ALBERT

Description: The Cap de Creus continental shelf and Cap de Creus canyon are located in the southern most sector of the Gulf of Lions, in the northwestern Mediterranean. The Cap de Creus continental shelf contains sandy and muddy sediments and an abrupt morpho­ logy, with rocky outcrops, relict bioherms, erosive features, and planar bedforms. The Cap de Creus canyon breaches the shelf at a depth of 110 m and denotes a marked dif­ ference in the morphology between the northern and the southern flank, reflecting a different depositional regime. The most common substrates correspond to coarse and medium sands (28%) and silty sediments (40%). The most common megabenthic assemblages of the shelf correspond to the communities of "offshore detritic" (31.95%) and "coastal terrigenous muds" (36.99%), mostly dominated by sea pens, alcyonaceans, and ceriantharians. The northern flank of the Cap de Creus canyon is predominantly depositional, whereas the southern flank is erosional. Rocky outcrops provide the sub­ stratum for cold­water coral (CWC) communities' development, in which the white coral Madrepora oculata is the most abundant species.

Description: Submarine groundwater discharge (SGD) into a shallow lagoon on the west coast of Mauritius Island (Flic-en-Flac) was investigated using radioactive (3H, 222Rn, 223Ra, 224Ra, 226Ra, 228Ra) and stable (2H, 18O) isotopes and nutrients. SGD intercomparison exercises were carried out to validate the various approaches used to measure SGD including radium and radon measurements, seepage rate measurements using manual and automated meters, sediment bulk conductivity and salinity surveys. SGD measurements using benthic chambers placed on the floor of the Flic-en-Flac Lagoon showed discharge rates up to 500 cm/day. Large variability in SGD was observed over distances of a few meters, which were attributed to different geomorphological features. Deployments of automated seepage meters captured the spatial and temporal variability of SGD with a mean seepage rate of 10 cm/day. The stable isotopic composition of submarine waters was characterized by significant variability and heavy isotope enrichment and was used to predict the contribution of fresh terrestrially derived groundwater to SGD (range from a few % to almost 100%). The integrated SGD flux, estimated from seepage meters placed parallel to the shoreline, was 35 m3/m day, which was in reasonable agreement with results obtained from a hydrologic water balance calculation (26 m3/m day). SGD calculated from the radon inventory method using in situ radon measurements were between 5 and 56 m3/m per day. Low concentrations of radium isotopes observed in the lagoon water reflected the low abundance of U and Th in the basalt that makes up the island. High SGD rates contribute to high nutrients loading to the lagoon, potentially leading to eutrophication. Each of the applied methods yielded unique information about the character and magnitude of SGD. The results of the intercomparison studies have resulted a better understanding of groundwater–seawater interactions in coastal regions. Such information is an important pre-requisite for the protection and management of coastal freshwater resources. Highlights ► Large fluctuations in SGD fluxes from 0 to 360 cm/day were observed. ► The integrated shoreline SGD fluxes were between 5 and 56 m3/m day. ► The groundwater contribution in SGD varied from a few % to almost 100%. ► The observed high SGD rates contributed to high nutrients loading to the lagoon.

Description: The boron isotope ratio (δ11B) of foraminifers and tropical corals has been proposed to record seawater pH. To test the veracity and practicality of this potential paleo-pH proxy in deep sea corals, samples of skeletal material from twelve archived modern Desmophyllum dianthus (D. dianthus) corals from a depth range of 274–1470 m in the Atlantic, Pacific, and Southern Oceans, ambient pH range 7.57–8.05, were analyzed for δ11B. The δ11B values for these corals, spanning a range from 23.56 to 27.88, are found to be related to seawater borate δ11B by the linear regression: δ11Bcoral=(0.76±0.28) δ11Bborate+(14.67±4.19) (1 standard error (SE)). The D. dianthus δ11B values are greater than those measured in tropical corals, and suggest substantial physiological modification of pH in the calcifying space by a value that is an inverse function of seawater pH. This mechanism partially compensates for the range of ocean pH and aragonite saturation at which this species grows, enhancing aragonite precipitation and suggesting an adaptation mechanism to low pH environments in intermediate and deep waters. Consistent with the findings of Trotter et al. (2011) for tropical surface corals, the data suggest an inverse correlation between the magnitude of a biologically driven pH offset recorded in the coral skeleton, and the seawater pH, described by the equation: ΔpH=pH recorded by coral−seawater pH=−(0.75±0.12) pHw+(6.88±0.93) (1 SE). Error analysis based on 95% confidence interval(CI) and the standard deviation of the regression residuals suggests that the uncertainty of seawater pH reconstructed from δ11Bcoral is ±0.07 to 0.12 pH units. This study demonstrates the applicability of δ11B in D. dianthus to record ambient seawater pH and holds promise for reconstructing oceanic pH distribution and history using fossil corals.

Description: Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr−1 (2.6 polyps per year). Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr−1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions.

Description: The purpose of this first synthesis is to summarize findings on the Yarlung Zangbo Suture Zone (YZSZ) ophiolites and discuss still remaining problems. The YZSZ studied for almost 30 years and is the youngest of the sutures recognized on Tibet Plateau. It is now acknowledged that the YZSZ is a complex assemblage of sedimentary, metamorphic and igneous rocks created during and shortly after the collision between India and Eurasia. The ages of the various lithologies span a time interval from the Jurassic to the Middle Miocene, with some Permian and Devonian exotic blocks from mélange zone. The YZSZ is characterized by ophiolitic complexes and ophiolitic mélange. The ophiolites are of two types: non dismembered and dismembered sections. The non disturbed sections, although tectonically reworked, are observed along the segment from Dazhuqu to Jiding in Xigaze area and Spontang ophiolite. The dismembered sequences are found in various locations such as Nidar, Kiogar, Jungbwa, Saga, Sangsang, Xigugabu, and Luobusa. The incomplete stratigraphic log could be connected to intraoceanic or orogenetic origins. The ophiolites are distributed into two groups of ages: the Luobusa, Zedang and Kiogar sequences being Jurassic-Lower Cretaceous whereas all other sequences are of Lower Cretaceous age. Compilation of geochronological data suggest that some ophiolite sequences might have evolved for over more than 70 My from their initial genesis to obduction which occurred around 70–90 My ago. Ophiolites differ in terms of petrological and geochemical aspects however, they were all generated in suprasubduction zone and more specifically in arc (few fore-arc) and back-arc settings. Synthesis of more than 700 geochemical analyses show variable mixing of components from N-MORB-type to IAT-CAB and to OIB end-members. The Jurassic ophiolites show the maximum of arc component while the Lower Cretaceous ones show little to strong mixing. In addition, most ophiolites were created in short lived (30 My) basins and generated close to the Eurasiatic continental margin. We propose that Ladakh–Tibet ophiolites were generated in a suprasubduction context similar to Mariana arc, interarc and back-arc or Tonga–Lau system. The variable arc signature of these ophiolites is directly related to their initial position within the suprasubduction system.

Description: The European sprat (Sprattus sprattus) was a main target species of the German GLOBEC program that investigated the trophodynamic structure and function of the Baltic and North Seas under the influence of physical forcing. This review summarizes literature on the ecophysiology of sprat with an emphasis on describing how environmental factors influence the life-history strategy of this small pelagic fish. Ontogenetic changes in feeding and growth, and the impacts of abiotic and biotic factors on vital rates are discussed with particular emphasis on the role of temperature as a constraint to life-history scheduling of this species in the Baltic Sea. A combination of field and laboratory data suggests that optimal thermal windows for growth and survival change during early life and are wider for eggs (5–17 °C) than in young (8- to 12-mm) early feeding larvae (5–12 °C). As larvae become able to successfully capture larger prey, thermal windows expand to include warmer waters. For example, 12- to 16-mm larvae can grow well at 16 °C and larger, transitional-larvae and early juveniles display the highest rates of feeding and growth at ∼18–22 °C. Gaps in knowledge are identified including the need for additional laboratory studies on the physiology and behavior of larvae (studies that will be particularly critical for biophysical modeling activities) and research addressing the role of overwinter survival as a factor shaping phenology and setting limits on the productivity of this species in areas located at the northern limits of its latitudinal range (such as the Baltic Sea). Based on stage- and temperature-specific mortality and growth potential of early life stages, our analysis suggests that young-of-the year sprat would benefit from inhabiting warmer, near-shore environments rather than the deeper-water spawning grounds such as the Bornholm Basin (central Baltic Sea). Utilization of warmer, nearshore waters (or a general increase in Baltic Sea temperatures) is expected to accelerate growth rates but also enhance the possibility for density-dependent regulation of recruitment (e.g., top-down control of zooplankton resources) acting during the late-larval and juvenile stages, particularly when sprat stocks are at high levels. Highlights ► Field, laboratory and modeling research on the ecophysiology of all sprat life stages is summarized. ► Environmental factors influencing growth and survival are revealed. ► Ontogenetic changes in thermal tolerance and prey requirements constrain life cycle scheduling. ► Gaps in knowledge are identified and future research efforts recommended on sprat recruitment dynamics. ► Exploring seasonal energy allocation will allow a mechanistic understanding of climate impacts.

Description: Throughout the last decades there has been a world-wide, general warming trend. In this study, we use the example of the Baltic Sea to resolve the overall estimated temperature trend into smaller, meso-scale spatial units. Afterwards, we investigate the spatially resolved potential impact of the temperature trend on larval survival for two important fish species, cod and sprat. We used two different sets of hydrographic data: (i) long-term temporally and depth-resolved data measured in situ originating from one geographic position and (ii) long-term horizontally resolved data, originating from a circulation model. In contrast to basin-wide integrated results, our modelling approach revealed different results related to smaller spatial scales. In shallow and coastal areas non-significant long-term temperature trends were observed. In some cases even decreasing temperature trends were found. Average distribution maps (1973–2010) of cod and sprat eggs and larvae confirmed the higher importance of central, deep basins as nursery grounds. Applying the temperature trends when calculating cod larval window of opportunity values, resulted in decreased durations of 1–3 days (~ 3–13%) in most areas. Sprat larval window of opportunity values mainly increased up to 4 days (~ 45%), indicating a potential reproduction advantage of sprat over cod under anticipated future temperature increase. Highlights ► We resolve the overall positive temperature trend in the Baltic into meso-scale spatial units and investigate the impact on larval survival for two important fish species, cod and sprat. ► In shallow and coastal areas non-significant or even negative temperature trends occurred. ► Cod larval window of opportunity values decreased by 1–3 days (~ 3–13%). ► Sprat larval window of opportunity values increased up to 4 days (~ 45%). ► Sprat will have a reproduction advantage over cod under anticipated future temperature change.

Description: Basin modeling and cross-section restoration from the northern East China Sea Shelf Basin reveal the timing of trap formation and petroleum generation. Cross-section restoration suggest that extension started in the Late Cretaceous and was interrupted by inversion at the end of Miocene that created large anticline structures, providing numerous petroleum traps. One-dimensional basin modeling of the JDZ-VII-I well show that the main phase of oil generation in the synrift fluvial shales in the Jeju Basin occurred during the Early Oligocene–middle Miocene period, predating the regional inversion. Thus, potential for large oil accumulations in the southern part of the basin is probably limited. Most of the petroleum are likely to have flowed toward the basin margin as well as basin center until the Late Miocene because no structures were available to capture them. The formation of anticline structures overlapped and/or postdated the main phase of gas generation in the Jeju Basin. This is probably why the JDZ-VII-1 is gas-prone with the gas trapped mainly in the anticlinal structures formed by the tectonic uplift. The source rocks in the southwestern part of the Domi Basin are immature for petroleum generation.

Description: The objective of the present study was to determine the action of beta-glucans as feed additives on the gene expression profile of some inflammatory-related cytokines from common carp (Cyprinus carpio L) during the early stages of a non-lethal bacterial infection with Aeromonas salmonicida. beta-glucan (MacroGard (R)), was administered daily to carp (6 mg per kg body weight) in the form of supplemented commercial food pellets for 14 days prior to infection. Control and treated fish were then intraperitoneally injected with PBS or 4 x 10(8) bacteria per fish and were sampled at time 0 and 6 h, 12 h, I day, 3 days and 5 days post-injection. Head kidney and gut were collected and the gene expression patterns for tnf alpha 1, tnf alpha 2, il1 beta, il6 and il10 were analyzed by quantitative PCR. Results obtained showed that treatment with beta-glucans generally down-regulated the expression of all measured genes when compared to their corresponding controls. After injection, highest changes in the gene expression levels were obtained at 6 h: particularly, in head kidney there was higher up-regulation of tnfa1 and tnfa2 in infected fish fed beta-glucans in comparison to control feed: however, in gut there was a significant down-regulation of tnf alpha 1, tnf alpha 2, il1 beta and il6 in infected fish fed beta-glucans. Analysis of carp specific antibodies against A. salmonicida 30 days after injection revealed their levels were reduced in the infected beta-glucan group. In conclusion, a diet supplemented with beta-glucan (MacroGard (R)) reduced the gene expression levels of some inflammation-related cytokines in common carp. Such a response appears to be dependent of organ studied and therefore the immunostimulant may be preventing an acute and potential dangerous response in gut, whilst enhancing the inflammatory response in head kidney when exposed to A. salmonicida

Description: Tectonic pseudotachylytes, i.e. quenched friction-induced silicate melts, record coseismic slip along faults and are mainly reported from the brittle crust in association with cataclasites. In this study, we document the occurrence of recrystallization of quartz to ultrafine-grained (grain size 1–2 μm) aggregates along microshear zones (50–150 μm thick) in the host rock adjacent to pseudotachylytes from two different faults within quartzite (Schneeberg Normal Fault Zone, Eastern Alps), and tonalite (Adamello fault, Southern Alps) in the brittle crust. The transition from the host quartz to microshear zone interior includes: (i) formation of high dislocation densities; (ii) fine (0.3–0.5 μm) polygonization to subgrains defined by disordered to well-ordered dislocation walls; (iii) development of a mosaic aggregate of dislocation-free new grains. The crystallographic preferred orientation (CPO) of quartz towards the microshear zone shows a progressive misorientation from the host grain, by subgrain rotation recrystallization, to a nearly random CPO possibly related to grain boundary sliding. These ultrafine aggregates appear to be typically associated with pseudotachylytes in nature. We refer the crystal plastic deformation of quartz accompanied by dramatic grain size refinement to the coseismic stages of fault slip due to high differential stress and temperature transients induced by frictional heating. Microshear zones localized on precursory fractures developed during the stages of earthquake rupture propagation and the very initial stages of fault slip. Thermal models indicate that the process of recrystallization, including recovery processes, occurred in a time lapse of a few tens of seconds.

Description: In this study we first evaluate the small-scale spatial variability of particulate export, using a set of synoptic thorium-234 activity observations sampled within a one-degree radius. These data show significant variability of surface thorium activity on scales of the order of 100 km (∼270–550 dpm m−3). This patchiness of export potentially affects the robustness of point observations and our interpretation of them. Motivated by these observations we subsequently couple an explicit model of thorium-234 dynamics to a coupled physical–biogeochemical basin model capable of resolving these small-scales. The model supports the observations in displaying marked thorium variability on spatial scales of the order of 100 km and smaller, with highest values in the regions of large eddy kinetic energy and large primary productivity. The model is also used to quantify the impact of small-scale variability on export estimates. Our model shows that the primary source of error associated with the presence of small-scale spatial variability is related to the standard assumptions of steady state and non-steady state (〉40% during bloom condition). The non-steady state method can misinterpret variations due to patchiness in thorium activity as temporal changes and lead to errors larger than those introduced by the simpler steady state approach. We show that the non-steady state approach could improve the flux estimates in some cases if the sampling was conducted in a Lagrangian framework. Undersampling the spatial variability results in further bias (〉20%) that can be reduced when the sampling density is increased. Finally, errors due to the dynamical transport of thorium associated with small-scale structures are relatively low (〈20%) except in regions of high eddy kinetic energy.

Description: Eclogites from the Tian Shan high-pressure/low-temperature (HP/LT) metamorphic belt show evidence for successively increasing metasomatic alteration with increasing retrograde, blueschist-facies overprint. To constrain the source(s) of the metasomatizing fluid and to evaluate elemental and isotopic changes during this overprint, two sequences of eclogite-blueschist transitions were investigated: A layered transition from eclogite to blueschist (FTS 9–1 sequence) and blueschist-facies overprinted pillow metabasalts (FTS 4 samples). Geochemical trends based on the relationships of K, Ba, Rb and Th are consistent with HP metasomatism, but distinct from typical seafloor alteration trends. In contrast, oxygen isotope ratios in garnet (δ18OV-SMOW = 7.3–8.7‰) and omphacite (δ18OV-SMOW = 8.2–9.7‰) are similar to δ18OV-SMOW in bulk low-temperature altered oceanic crust (AOC), suggesting O isotopic preservation of a seafloor alteration signature. Carbonate crystallization related to the metasomatic overprint demonstrate CO2 mobility during subduction and potential C storage in HP metamorphic rocks. Carbon isotope ratios in the two sequences differ markedly: Disseminated calcite in the layered FTS 9–1 sequence has δ13CV-PDB = − 9.14 ± 0.19‰, whereas vein-forming ankerite in the pillow metabasalts has δ13CV-PDB = − 2.08 ± 0.12‰. The ankerite reflects an inorganic marine/hydrothermal signature, as observed in ophiolites, whereas the low δ13CV-PDB values from the calcite point to a contribution of organic carbon. The time when the metasomatic overprint occurred is estimated to be ~ 320 ± 11 Ma based on a Rb-Sr isochron age of six blueschist samples from the pillow metabasalts, which is in agreement with active subduction in this region. Initial (T = 320 Ma) 87Sr/86Sr ratios for all HP/LT rocks range from 0.7059 – 0.7085, and εNd320Ma varies from − 0.4 to + 10.9. Both eclogite-blueschist sequences have initial Sr isotope compositions (87Sr/86Sr ~ 0.707) that are significantly higher than those of typical oceanic mantle-derived basalts. They are thought to derive from a fluid that preserved the Sr isotopic signature of seawater by fluid-rock interaction with seawater-altered oceanic lithosphere in a subduction channel. Mixing models between eclogite and various fluids suggest that the contribution of a sediment-derived fluid was likely less than 20%. A fluid predominantly derived from seawater-altered oceanic lithosphere is also supported by the calculated O isotope composition of the fluids (10.2 – 11.2‰). It is thus evident that subduction channel fluids carry complex, mixed elemental and isotopic signatures, which reflect the composition of their source rocks modified by interaction with various other lithologies. Highlights ► Eclogites from the Tian Shan show blueschist-facies metasomatic overprint ► Fluid-induced metasomatism occurred at 320 ± 11 Ma ► Fluid predominantly derived from seawater-altered oceanic lithosphere ► Carbonates reflect C sequestration of mixture of organic and inorganic components

Description: Cyanobacteria blooms in the Baltic Sea appear after upwelling events, which transport phosphate-rich intermediate water to the surface. The growth potential of diazotrophic cyanobacteria in upwelled water was studied in a mesocosm (tank) experiment in summer 2007. An Anabaena bloom was only induced in the tanks filled with upwelled surface water but not in those filled with surface water from outside the upwelling cell and with intermediate water. The low initial cyanobacteria biomass in the intermediate water could not grow to bloom concentrations within three weeks. It is concluded that mixing of upwelled water with surrounding surface water forms a precondition for a cyanobacteria bloom. An additional mesocosm experiment conducted in 2009 revealed that mixing of intermediate water with surface water had the same stimulating effect on nitrogen fixation and cyanobacteria growth as artificial phosphate input. Phosphate input stimulates the growth of Nodularia and Anabaena more than that of Aphanizomenon. We suggest that the upwelled phosphate-rich intermediate water has to be mixed with the surface water containing physiologically “young” cyanobacteria biomass of at least 20 mg/m3 as an inoculum in order to initiate a cyanobacteria bloom.

Description: In the Baltic Sea, excess phosphorus after the spring bloom or phosphorus input from deeper layers e.g. by upwelling are nutrient sources for the development of filamentous cyanobacteria. The objective of this study was to investigate the ability of filamentous cyanobacteria to accumulate phosphate in depths within or below the thermocline under stratified conditions in the water column. Inorganic nutrient concentrations, as well as phytoplankton composition, chlorophyll a, POC, PON and POP and the ratios between them of water samples and of isolated filamentous cyanobacteria were estimated in five horizons of the upper 30 m surface layer together with phosphorus uptake and nitrogen fixation. During the investigation period, the water column was stratified with a surface temperature of 16 °C–18 °C in the eastern Gotland Basin. Cyanobacteria surface blooms occurred and constituted between 28 and 68% of the total phytoplankton biomass in the upper 5 m surface layer. Deduced from POC:POP ratios of 264–977, cyanobacteria were phosphorus depleted here. The POC:POP ratios became lower with increasing depth. In depths below 15 m, the cyanobacteria indicated phosphorus enrichment by POC:POP ratio declining down to 75 due to a forced gross uptake of 0.62 nmol P μg−1 Chla h−1compared to an uptake rate of 0.13 nmol P μg−1 Chla h−1 measured in the surface layer. Thus, filamentous cyanobacteria can acquire phosphate in deeper layers which enables further growth when they reach the surface. However, they occurred in low abundances there. In 30 m depth, cyanobacteria accounted for only 0.3–10% of their biomass in the surface layer. This contribution to bloom formation may therefore be of minor importance compared to other sources.

Description: High-resolution sedimentary records of major and minor elements (Al, Ba, Ca, Sr, Ti), total organic carbon (TOC), and profiles of pore water constituents (View the MathML sourceSO42-, CH4, Ca2+, Ba2+, Mg2+, alkalinity) were obtained for two gravity cores (core 755, 501 m water depth and core 214, 1686 m water depth) from the northwestern Black Sea. The records were examined in order to gain insight into the cycling of Ba in anoxic marine sediments characterized by a shallow sulfate–methane transition (SMT) as well as the applicability of barite as a primary productivity proxy in such a setting. The Ba records are strongly overprinted by diagenetic barite (BaSO4) precipitation and remobilization; authigenic Ba enrichments were found at both sites at and slightly above the current SMT. Transport reaction modeling was applied to simulate the migration of the SMT during the changing geochemical conditions after the Holocene seawater intrusion into the Black Sea. Based on this, sediment intervals affected by diagenetic Ba redistribution were identified. Results reveal that the intense overprint of Ba and Baxs (Ba excess above detrital average) strongly limits its correlation to primary productivity. These findings have implications for other modern and ancient anoxic basins, such as sections covering the Oceanic Anoxic Events which Ba is frequently used as a primary productivity indicator. Our study also demonstrates the limitations concerning the use of Baxs as a tracer for downward migrations of the SMT: due to high sedimentation rates at the investigated sites, diagenetic barite fronts are buried below the SMT within a relatively short period. Thus, ‘relict’ barite fronts would only be preserved for a few thousands of years, if at all.

Description: Seismic coherency measures, such as similarity and dip of maximum similarity, were used to characterize mass transport deposits (MTDs) in the Ulleung Basin, East Sea, offshore Korea. Using 2-D and 3-D seismic data several slope failure masses have been identified near drill site UBGH1-4. The MTDs have a distinct seismic character and exhibit physical properties similar to gas hydrate bearing sediment: elevated electrical resistivity and P-wave velocity. Sediments recovered from within the MTDs show a reworked nature with chaotic assemblage of mud-clasts. Additionally, the reflection at the base of MTDs is polarity reversed relative to the seafloor, similarly to the bottom-simulating reflector commonly used to infer the presence of gas hydrates. The MTDs further show regional seismic blanking (absence of internal reflectivity), which is yet another signature often attributed to gas hydrate bearing sediments. At the drill site UBGH1-4, no gas hydrate was recovered in sediment-cores from inside a prominent MTD unit. Instead, pore-filling gas hydrate was recovered only within thin turbidite sand layers near the base of the gas hydrate stability zone. With the analysis of seismic attributes, the seismic character of the prominent MTD (Unit 3) was investigated. The base of the MTD unit exhibits deep grooves interpreted as gliding tracks from either outrunner blocks or large clasts that were dragged along the paleo-seafloor. Similar seismic features were identified on the seafloor although the length of the gliding tracks on the seafloor is much shorter (a few hundred meters to ∼1 km), compared to over 10 km long tracks at the base of the MTD. The seismic coherency attributes allowed to estimate the volume of the failed sediment as well as the direction of the flow of sediment. Tracking the MTD and extrapolating its spatial extent from the 3-D seismic volume to adjacent 2-D seismic profiles, a possible source region of this mass failure was defined ∼50 km upslope of Site UBGH1-4.

Description: Analytical challenges in obtaining high quality measurements of rare earth elements (REEs) from small pore fluid volumes have limited the application of REEs as deep fluid geochemical tracers. Using a recently developed analytical technique, we analyzed REEs from pore fluids collected from Sites U1325 and U1329, drilled on the northern Cascadia margin during the Integrated Ocean Drilling Program (IODP) Expedition 311, to investigate the REE behavior during diagenesis and their utility as tracers of deep fluid migration. These sites were selected because they represent contrasting settings on an accretionary margin: a ponded basin at the toe of the margin, and the landward Tofino Basin near the shelf's edge. REE concentrations of pore fluid in the methanogenic zone at Sites U1325 and U1329 correlate positively with concentrations of dissolved organic carbon (DOC) and alkalinity. Fractionations across the REE series are driven by preferential complexation of the heavy REEs. Simultaneous enrichment of diagenetic indicators (DOC and alkalinity) and of REEs (in particular the heavy elements Ho to Lu), suggests that the heavy REEs are released during particulate organic carbon (POC) degradation and are subsequently chelated by DOC. REE concentrations are greater at Site U1325, a site where shorter residence times of POC in sulfate-bearing redox zones may enhance REE burial efficiency within sulfidic and methanogenic sediment zones where REE release ensues. Cross-plots of La concentrations versus Cl, Li and Sr delineate a distinct field for the deep fluids (z 〉 75 mbsf) at Site U1329, and indicate the presence of a fluid not observed at the other sites drilled on the Cascadia margin. Changes in REE patterns, the presence of a positive Eu anomaly, and other available geochemical data for this site suggest a complex hydrology and possible interaction with the igneous Crescent Terrane, located east of the drilled transect.

Description: In western Canada gas hydrates have been thought to exist primarily in the Cascadia accretionary prism off southern Vancouver Island, British Columbia (BC). We present evidence for the existence of gas hydrate in folds and ridges of the Winona Basin up to 40 km seaward from the foot of the continental slope off northern Vancouver Island. The occurrence of a bottom-simulating reflector (BSR) observed in a number of vintage seismic reflection profiles is strongly correlated to faulted, and folded sedimentary ridges and buried folds. The observed tectonic structures of the Winona Basin are within the rapidly evolving Juan de Fuca – Cascadia – Queen Charlotte triple junction off BC. Re-processing of multi-channel data imaged mildly to strongly deformed sediments; the BSR is confined to sediments with stronger deformation. Changes in the amplitude character of sediment-reflections above and below the depth of the base of gas hydrate stability zone were also used as an indicator for the presence of gas hydrate. Additionally, regional amplitude and frequency reduction below some strong BSR occurrences may indicate free gas accumulations. Gas hydrate formation in the Winona Basin appears strongly constrained to folds and ridges and thus correlated to deeper-routed fluid-advection regimes. Methane production from in situ microbial activities as a source of gas to form gas hydrates, as proposed to be a major contributor for gas hydrates within the accretionary prism to the south, appears to be insufficient to produce the widespread gas hydrate occurrences in the Winona Basin. Potential reasons for the lack of sufficient in situ gas production may be that sedimentation rates are 5–100 times higher than those in the accretionary prism so that available organic carbon moves too quickly through the gas hydrate stability field. The confinement of BSRs to ridges and folds within the Winona Basin results in an areal extent of gas hydrate occurrences that is a factor of five less than what is expected from regional gas hydrate stability field mapping using water-depth (pressure) as the only controlling factor only.

Description: The Gibraltar arc, spans a complex portion of the Africa-Eurasia plate boundary marked by slow oblique convergence and intermediate and deep focus seismicity. The seemingly contradictory observations of a young extensional marine basin surrounded by an arcuate fold-and-thrust belt, have led to competing geodynamic models (delamination and subduction). Geophysical data acquired in the past decade provide a test for these models and support a narrow east-dipping, subduction zone. Seismic refraction studies indicate oceanic crust below the western Gulf of Cadiz. Tomography of the upper mantle reveals a steep, east-dipping high P-wave velocity body, beneath Gibraltar. The anisotropic mantle fabric from SKS splitting shows arc-parallel "fast directions", consistent with toroidal flow around a narrow, westward retreating subducting slab. The accompanying WSW advance of the Rif-Betic mountain belt has constructed a thick pile of deformed sediments, an accretionary wedge, characterized by west-vergent thrust anticlines. Bathymetric swath-mapping images an asymmetric embayment at the deformation front where a 2 km high basement ridge has collided. Subduction has slowed significantly since 5 Ma, but deformation of recent sediments and abundant mud volcanoes suggest ongoing activity in the accretionary wedge. Three possible origins for this deformation are discussed; gravitational spreading, overall NW-SE convergence between Africa and Iberia and finally a WSW tectonic push from slow, but ongoing roll-back subduction. In the absence of arc volcanism and shallow dipping thrust type earthquakes, evidence in favor of present-day subduction can only be indirect and remains the object of debate. Continued activity of the subduction offers a possible explanation for great (M〉8.5) earthquakes known to affect the area, like the famous 1755 Great Lisbon earthquake. Recent GPS studies show SW motion of stations in N Morocco at velocities of 3-6 mm/yr indicating the presence of an independent block, a "Rif-Betic-Alboran" microplate, situated between Iberia and Africa

Description: Mass-transport-deposits (MTDs) and hemipelagic mud interbedded with sandy turbidites are the main sedimentary facies in the Ulleung Basin, East Sea, offshore Korea. The MTDs show similar seismic reflection characteristics to gas-hydrate-bearing sediments such as regional seismic blanking (absence of internal reflectivity) and a polarity reversed base-reflection identical to the bottom-simulating reflector (BSR). Drilling in 2007 in the Ulleung Basin recovered sediments within the MTDs that exhibit elevated electrical resistivity and P-wave velocity, similar to gas hydrate-bearing sediments. In contrast, hemipelagic mud intercalated with sandy turbidites has much higher porosity and correspondingly lower electrical resistivity and P-wave velocity. At drill-site UBGH1-4 the bottom half of one prominent MTD unit shows two bands of parallel fractures on the resistivity log-images indicating a common dip-azimuth direction of about ∼230° (strike of ∼140°). This strike-direction is perpendicular to the seismically defined flow-path of the MTD to the north-east. At Site UBGH1-14, the log-data suggest two zones with preferred fracture orientations (top: ∼250°, bottom: ∼130°), indicating flow-directions to the north-east for the top zone, and north-west for the bottom zone. The fracture patterns may indicate post-depositional sedimentation that gave rise to a preferred fracturing possibly linked to dewatering pathways. Alternatively, fractures may be related to the formation of pressure-ridges common within MTD units. For the interval of observed MTD units, the resistivity and P-wave velocity log-data yield gas hydrate concentrations up to ∼10% at Site UBGH1-4 and ∼25% at Site UBGH1-14 calculated using traditional isotropic theories such as Archie's law or effective medium modeling. However, accounting for anisotropic effects in the calculation to honor observed fracture patterns, the gas hydrate concentration is overall reduced to less than 5%. In contrast, gas hydrate was recovered at Site UBGH1-4 near the base of gas hydrate stability zone (GHSZ). Log-data predict gas hydrate concentrations of 10–15% over an interval of 25 m above the base of GHSZ. The sediments of this interval are comprised of the hemipelagic mud and interbedded thin sandy turbidites, which did contain pore-filling gas hydrate as identified from pore-water freshening and core infra-red imaging. Seismically, this unit reveals a coherent parallel bedding character but has overall faint reflection amplitude. This gas-hydrate-bearing interval can be best mapped using a combination of regular seismic amplitude and seismic attributes such as Shale indicator, Parallel-bedding indicator, and Thin-bed indicator.

Description: Plant breeding and improved management options have made remarkable progress in increasing crop yields during the past century. However, climate change projections suggest that large yield losses will be occurring in many regions, particularly within sub-Saharan Africa. The development of climate-ready germplasm to offset these losses is of the upmost importance. Given the time lag between the development of improved germplasm and adoption in farmers’ fields, the development of improved breeding pipelines needs to be a high priority. Recent advances in molecular breeding provide powerful tools to accelerate breeding gains and dissect stress adaptation. This review focuses on achievements in stress tolerance breeding and physiology and presents future tools for quick and efficient germplasm development. Sustainable agronomic and resource management practices can effectively contribute to climate change mitigation. Management options to increase maize system resilience to climate-related stresses and mitigate the effects of future climate change are also discussed.

Description: Gas hydrate saturations were calculated based on Archie's relation and rock-physics modeling utilizing log measurements of electrical resistivity and P-wave velocity through the gas hydrate stability zone (GHSZ) at two sites in the Krishna Godavari (KG) basin off the East Coast of India. Acoustic impedance inversion was then performed around the well sites for regional extrapolation of the borehole data. Well-log based gas hydrate concentration estimates and core data are in general agreement with the seismic impedance inversion results at the individual well sites. However, the correlation with seismic data and thus the confidence in the extrapolation decreases with distance from the well site. To address the general problem of unknown regional confidence limits in the extrapolation and aid in regional gas hydrate assessment analyses, a new approach is introduced by calculating the running-sum of the seismic similarity attribute across the gas hydrate stability zone. The running-sum of the similarity attribute can be used locally on a 2D seismic line or 3D seismic volume for defining the limit of well-data extrapolation around a given well site. By normalizing the running-sum of the similarity attribute from all available 2D seismic data in the KG basin, a regional map was generated yielding effective confidence limits for extrapolation of well-log data. Such maps of regional confidence limits can be used strategically in basin-wide gas hydrate assessments as they provide a measure of probability to find a given gas hydrate concentration, and may also offer a guide for defining a minimum regional spacing between well-sites to address the overall structural complexity of the basin (which is reflected in the similarity of the seismic data).

Description: The eastward penetration of Atlantic-derived water (ADW) into the Eurasian Basin of the Arctic Ocean was investigated at the western Laptev Sea continental margin for the time since c. 17.6 ka. Using a high-resolution investigation of the lithology, geochemistry, planktic and benthic foraminifers, and ostracods on a sediment core from 270 m water depth major steps in the environmental evolution of the region are recognized. In general, ADW was continuously present in the study area. Between 17.6 and 15.4 ka ADW manifested itself through open-water polynyas and associated upwelling events. Comparison between the Laptev Sea and northern Svalbard shelf using Cassidulina neoteretis allows assuming an unmodified subsurface inflow of ADW within its northern branch between 15.4 and 13.2, which was strongest after 14.7-ka and in line with the overall climate amelioration. A local freshwater event at 13 ka followed by shelf flooding and the establishment of a freshened shelf water mass resulted in an off-shelf displacement of ADW from the studied site as suggested by the disappearance of C. neoteretis between 12 and 7 ka. As evidenced by an abundance peak in Nonion labradoricum, the sea-ice marginal zone was located at the site around 12–11 ka but then shifted northward during the early Holocene warming. Enhanced ADW inflow since 7 ka correlated with climate cooling and southward retreat of the seasonal drift-ice margin. The inflow of ADW during mid–late Holocene differed from deglacial times because of the combined influence of northern and eastern ADW branches.

Description: Four new cyclic lipopeptides, cyclo-(AFA-Ser-Gln-Asn-Tyr-Asn-Ser-Thr), named cyclodysidins A–D, were isolated from the broth culture of Streptomyces strain RV15 associated with the marine sponge Dysidea tupha. The sequences of the amino acid building blocks in the compounds and their structures were determined by 1D- and 2D-NMR techniques and CID-MS/MS experiments. The absolute configurations of all α-amino acids were determined by HPLC analysis after derivatization with Marfey’s reagent and comparison with commercially available reference samples, while those two of the β-amino fatty acids were determined by using racemic and enantiopure reference samples synthetically prepared.

Description: Most authigenic carbonates previously recovered from the Cascadia slope have 87Sr/86Sr signatures that reflect shallow precipitation in equilibrium with coeval seawater. There is also evidence for carbonate formation supported by fluids that have been modified by reactions with the incoming Juan de Fuca plate (87Sr/86Sr = 0.7071; Teichert et al., 2005) or with terrigenous turbidites (87Sr/86Sr = 0.70975 to 0.71279; Sample et al., 1993). We report on the strontium isotopic composition of carbonates and fluids from IODP Site U1329 and nearby Barkley Canyon (offshore Vancouver Island), which have strontium isotope ratios as low as 0.70539. Whereas the strontium and oxygen isotopic compositions of carbonates from paleoseeps in the uplifted Coast Range forearc indicate formation in ambient bottom seawater, several samples from the Pysht/Sooke Fm. show a 87Sr-depleted signal (87Sr/86Sr = 0.70494 and 0.70511) similar to that of the anomalous Site U1329 and Barkley Canyon carbonates. Our data, when analyzed in the context of published elemental and isotopic composition of these carbonates (Joseph et al., 2012), point to two formation mechanisms: 1) shallow precipitation driven by the anaerobic oxidation of methane (AOM) with δ13C values as low as − 50‰ and contemporaneous 87Sr/86Sr seawater ratios, and 2) carbonate precipitation driven by fluids that have circulated through the oceanic crust, which are depleted in 87Sr. Carbonates formed from the second mechanism precipitate both at depth and at sites of deep-sourced fluid seepage on the seafloor. The 87Sr-depleted carbonates and pore fluids found at Barkley Canyon represent migration of a deep, exotic fluid similar to that found in high permeability conglomerate layers at 188 mbsf of Site U1329, and which may have fed paleoseeps in the Pysht/Sooke Fm. These exotic fluids likely reflect interaction with the 52–57 Ma igneous Crescent Terrane, which supplies fluids with high calcium, manganese and strontium enriched in the non-radiogenic nucleide. Tectonic compression and dehydration reactions then force these fluids updip, where they pick up the thermogenic hydrocarbons and 13C-enriched dissolved inorganic carbon that are manifested in fluids and carbonates sampled at Barkley Canyon and at Site U1329. The Crescent Terrane may have sourced cold seeps in this margin since at least the late Oligocene.

Description: The association between beta-glucan (MacroGard (R)) supplemented feed and apoptosis in immune-related organs of common carp (Cyprinus carpio) was studied using fluorescence microscopy and real-time PCR. In addition the effect of Aeromonas salmonicida, LPS and Poly(I:C) injections on this relationship was evaluated. Whilst acridine orange staining revealed that apoptosis levels were independent of MacroGard (R) and LPS/Poly(1:C) administration or their combination, it was shown that injection with A. salmonicida increased the percentage of apoptotic cells irrespective of the feeding regime. It was apparent that in all the treatments gene expression profiles displayed organ and time dependency. For example no effect was observed at 7 days of MacroGard (R) administration while 25 days of feeding led to increased iNOS expression and differential up-regulation of anti- or pro-apoptotic genes depending on organ. This may indicate differences in NO sensitivity. MacroGard (R) also led to an elevation of pro- as well as anti-apoptotic genes in LPS or Poly(1:C) injected fish, while LPS/Poly(I:C) alone had little effect. A. salmonicida caused enhanced iNOS expression and it is possible that the type of apoptosis pathway induced is organ dependent as Caspase 9 is induced in mid-gut but not in pronephros. These results indicate that MacroGard (R) feeding alone or in combination with other pathogenic factors did not induce significant apoptosis in immune organs

Description: A reconstruction of Holocene sea ice conditions in the Fram Strait provides insight into the palaeoenvironmental and palaeoceanographic development of this climate sensitive area during the past 8500 years BP. Organic geochemical analyses of sediment cores from eastern and western Fram Strait enable the identification of variations in the ice coverage that can be linked to changes in the oceanic (and atmospheric) circulation system. By means of the sea ice proxy IP25, phytoplankton-derived biomarkers and ice rafted detritus (IRD) increasing sea ice occurrences are traced along the western continental margin of Spitsbergen throughout the Holocene, which supports previous palaeoenvironmental reconstructions that document a general cooling. A further significant ice advance during the Neoglacial is accompanied by distinct sea ice fluctuations, which point to short-term perturbations in either the Atlantic Water advection or Arctic Water outflow at this site. At the continental shelf of East Greenland, the general Holocene cooling, however, seems to be less pronounced and sea ice conditions remained rather stable. Here, a major Neoglacial increase in sea ice coverage did not occur before 1000 years BP. Phytoplankton-IP25 indices (“PIP25-Index”) are used for more explicit sea ice estimates and display a Mid Holocene shift from a minor sea ice coverage to stable ice margin conditions in eastern Fram Strait, while the inner East Greenland shelf experienced less severe to marginal sea ice occurrences throughout the entire Holocene. Highlights ► Biomarker and IRD data give insight into Holocene sea ice conditions in Fram Strait. ► We find increasing sea ice coverage off West Spitsbergen throughout the Holocene. ► Oceanic/atmospheric variability caused Neoglacial sea ice fluctuations. ► Ice conditions along East Greenland shelf remain rather stable until 1000 years BP.

Description: The influence of various wind and wave conditions on the variability of downwelling irradiance Ed (490 nm) in water is subject of this study. The work is based on a two-dimensional Monte Carlo radiative transfer model with high spatial resolution. The model assumes conditions that are ideal for wave focusing, thus simulation results reveal the upper limit for light fluctuations. Local wind primarily determines the steepness of capillary-gravity waves which in turn dominate the irradiance variability near the surface. Down to 3 m depth, maximum irradiance peaks that exceed the mean irradiance Ed by a factor of more than 7 can be observed at low wind speeds up to 5 m s−1. The strength of irradiance fluctuations can be even amplified under the influence of higher ultra-gravity waves; thereby peaks can exceed 11 Ed. Sea states influence the light field much deeper; gravity waves can cause considerable irradiance variability even at 100 m depth. The simulation results show that under realistic conditions 50% radiative enhancements compared to the mean can still occur at 30 m depth. At greater depths, the underwater light variability depends on the wave steepness of the characteristic wave of a sea state; steeper waves cause stronger light fluctuations.

Description: The impacts of natural atmospheric variability and anthropogenic climate change on the spatial distribution, seasonality, structure, and productivity of North Pacific plankton groups are investigated by means of an Earth System Model (ESM) that contains a plankton model with variable stoichiometry. The ESM is forced with observed greenhouse gases for the 20th century and with the Intergovernmental Panel on Climate Change A1B Emission Scenario for the 21st century. The impacts of the two main modes of variability – connected with the Aleutian Low (AL) strength and with the North Pacific Oscillation (NPO) – are considered. When the AL is strong, primary productivity and chlorophyll concentrations are higher in the central Pacific, the seasonality of plankton is enhanced, and the classical grazing chain is stimulated, whereas in the Alaskan Gyre the model simulates a chlorophyll decrease and a shift toward smaller phytoplankton species. A stronger NPO increases productivity and chlorophyll concentration at ∼45°N. In the anthropogenic climate change scenario, simulated sea surface temperature is 4 °C higher with respect to contemporary conditions, leading to reduced mixing and nutrient supply at middle-subpolar latitudes. The seasonal phytoplankton bloom is reduced and occurs one month earlier, the flow of carbon to the microbial loop is enhanced, and phytoplanktonic stoichiometry is nutrient-depleted. Primary productivity is enhanced at subpolar latitudes, due to increased ice-free regions and possibly to temperature-related photosynthesis stimulation. This study highlights that natural climate variability may act alternatively to strengthen or to weaken the human-induced impacts, and that in the next decades it will be difficult to distinguish between internal and external climate forcing on North Pacific plankton groups. Highlights ► A plankton model with variable stoichiometry has been used in a coupled climate study. ► Natural climate variations modify North Pacific plankton biomass by 10–30% while a warming scenario decreases primary production up to 50%. ► DOC production and the microbial foodweb will be favored in a warmer North Pacific. ► Positive phases of natural fluctuations counteract the impacts of global warming. ► Natural and anthropogenic impacts are distinguishable only in the second part of the 21st century.

Description: The copepod Calanus sinicus is a common and abundant species in the shelf waters of the western North Pacific from Japan to Vietnam, and is a main food source for crucial fish species. This study examined the effect of food and light on the swimming behavior of this species. The swimming activity was assessed by using 2 approaches that focused on the dynamics of swimming states and the statistical properties of their trajectories. We discovered that the complexity of swimming paths was reduced under illuminated conditions, and intensified in the absence of food. The swimming activity in such conditions was characterized by a less tortuous shape of trajectories, a lower instantaneous swimming velocity, and a lower recurrence of extreme events. In addition, the entropy of swimming paths decreased when food was included, and the minimal entropy was reached in dark conditions and presence of food, indicating predictable behavior. A general increase in swimming activity was dominated by the slow swimming state. The variations in the swimming activity of adult females exhibited an adaptive pattern that allowed maximizing the exploitation of the three-dimensional, and generally diluted environment that the copepods inhabit, as well as limiting the risk of the predation. ⺠We used robust numerical techniques to identify behavioral patterns of C. sinicus. ⺠The light and food availability plays key role in C. sinicus. ⺠C. Sinicus exhibits an adaptive strategy for feeding success and minimize risk. ⺠Mechanistic understanding of Calanus sinicus feeding ecology.

Description: The world's oceans are warming and becoming more acidic. Both stressors, singly or in combination, impact marine species, and ensuing effects might be particularly serious for early life stages. To date most studies have focused on ocean acidification (OA) effects in fully marine environments, while little attention has been devoted to more variable coastal ecosystems, such as the Western Baltic Sea. Since natural spatial and temporal variability of environmental conditions such as salinity, temperature or pCO(2) impose more complex stresses upon organisms inhabiting these habitats, species can be expected to be more tolerant to OA (or warming) than fully marine taxa. We present data on the variability of salinity, temperature and pH within the Kiel Fjord and on the responses of the barnacle Amphibalanus improvisus from this habitat to simulated warming and OA during its early development. Nauplii and cyprids were exposed to different temperature (12, 20 and 27 degrees C) and pCO(2) (nominally 400, 1250 and 3250 mu atm) treatments for 8 and 4 weeks, respectively. Survival, larval duration and settlement success were monitored. Warming affected larval responses more strongly than OA. Increased temperatures favored survival and development of nauplii but decreased survival of cyprids. OA had no effect upon survival of nauplii but enhanced their development at low (12 degrees C) and high (27 degrees C) temperatures. In contrast, at the intermediate temperature (20 degrees C), nauplii were not affected even by 3250 mu atm pCO(2). None of the treatments significantly affected settlement success of cyprids. These experiments show a remarkable tolerance of A. improvisus larvae to 1250 mu atm pCO(2), the level of OA predicted for the end of the century

Description: Fish stocks can be considered as natural capital stocks providing harvestable fish. Fishing at low stock sizes means borrowing from the natural asset. While fishing a particular quantity generates immediate profits and income, an interest rate has to be paid in terms of foregone future fishing income, as the fish stock's reproductive capacity remains low and fishing costs stay high. In this paper we propose to apply the concept of shadowinterest rate to quantify the degree of overfishing. It incorporates the relevant biological and economic information and compares across fish stocks.We calculate the shadow interest rates for 13major European fish stocks and find these rates to range from10% tomore than 200%. The concept of the shadow interest rate can be used to make the economic consequences of overfishing transparent and to evaluate the profitability of shortterm catch reductions as investments in natural capital stocks.

Description: The Cenozoic tectonic evolution of the South China Sea is reflected in diverse tectonic processes including continental rifting, seafloor spreading, subduction, terrane collision and strike-slip fault movement. A continent-ocean transition zone in the northern South China Sea caused by the lithospheric extension when the continent underwent break-up, rifting and later seafloor spreading, is clearly imaged in the multi-channel seismic data presented in this study. The morphological units of the continent-ocean transition zone are the rift-depression, the volcanic zone and tilted fault blocks. The volcanic zone represents a highest extension zone within the continent-ocean transition zone and is mainly distributed in the southern slope uplift zone along the northern passive margin of the South China Sea. The large listric-normal faults bounding the Dongsha Rise and Baiyun Sag are evidenced in the seismic image. The passive margin in the northern South China Sea underwent the wide-rift to narrow-rift process in the transition zone as inferred from the relation between the surface heat flow and initial rifted crustal thickness. The continent-ocean transition zone in the continental margin of the South China Sea is consistent with high heat flow zone (average 90 mW.m(-2)) observed in the previous heat flow measurements and at ODP Site 1148, and is manifested in a sharp change of the P-wave velocity. The rifted margin of the South China Sea is a non-typical magma poor passive margin or an intermediary form between the Iberian-type non-volcanic and the Greenland-type volcanic margin compared to the world's typical passive margins

Description: The Arctic featured the strongest surface warming over the globe during the recent decades, and the temperature increase was accompanied by a rapid decline in sea ice extent. However, little is known about Arctic sea ice change during the Early Twentieth Century Warming (ETCW) during 1920–1940, also a period of a strong surface warming, both globally and in the Arctic. Here, we investigate the sensitivity of Arctic winter surface air temperature (SAT) to sea ice during 1875–2008 by means of simulations with an atmospheric general circulation model (AGCM) forced by estimates of the observed sea surface temperature (SST) and sea ice concentration. The Arctic warming trend since the 1960s is very well reproduced by the model. In contrast, ETCW in the Arctic is hardly captured. This is consistent with the fact that the sea ice extent in the forcing data does not strongly vary during ETCW. AGCM simulations with observed SST but fixed sea ice reveal a strong dependence of winter SAT on sea ice extent. In particular, the warming during the recent decades is strongly underestimated by the model, if the sea ice extent does not decline and varies only seasonally. This suggests that a significant reduction of Arctic sea ice extent may have also accompanied the Early Twentieth Century Warming, pointing toward an important link between anomalous sea ice extent and Arctic surface temperature variability.

Description: 2-D seismic data from the top and the western slope of Mergui Ridge in water depths between 300 and 2200 m off the Thai west coast have been investigated in order to identify mass transport deposits (MTDs) and evaluate the tsunamigenic potential of submarine landslides in this outer shelf area. Based on our newly collected data, 17 mass transport deposits have been identified. Minimum volumes of individual MTDs range between 0.3 km3 and 14 km3. Landslide deposits have been identified in three different settings: (i) stacked MTDs within disturbed and faulted basin sediments at the transition of the East Andaman Basin to the Mergui Ridge; (ii) MTDs within a pile of drift sediments at the basin-ridge transition; and (iii) MTDs near the edge of/on top of Mergui Ridge in relatively shallow water depths (〈 1000 m). Our data indicate that the Mergui Ridge slope area seems to have been generally unstable with repeated occurrence of slide events. We find that the most likely causes for slope instabilities may be the presence of unstable drift sediments, excess pore pressure, and active tectonics. Most MTDs are located in large water depths (〉 1000 m) and/or comprise small volumes suggesting a small tsunami potential. Moreover, the recurrence rates of failure events seem to be low. Some MTDs with tsunami potential, however, have been identified on top of Mergui Ridge. Mass-wasting events that may occur in the future at similar locations may trigger tsunamis if they comprise sufficient volumes. Landslide tsunamis, emerging from slope failures in the working area and affecting western Thailand coastal areas therefore cannot be excluded, though the probability is very small compared to the probability of earthquake-triggered tsunamis, arising from the Sunda Trench.

Description: This study investigates the controls on organic carbon and molybdenum (Mo) accumulation in sediments deposited within the Western Interior Seaway across the Cenomanian–Turonian boundary interval (94.34–93.04 Ma) including Oceanic Anoxic Event 2 (OAE2). Carbon fluxes to the sediment–water interface (reflecting changes in primary productivity) and bottom-water oxygen concentrations (reflecting preservation effects) are reconstructed from field data and used to constrain a benthic model that simulates the geochemistry of unconsolidated sediments as they were deposited. The results show that increased availability of reactive iron prevents Mo sequestration as thiomolybdate (MoS42 −) during OAE2 (O2 ~ 105 μM) by (i) inhibiting sulfate reduction, and (ii) buffering any free sulfide that becomes available. In the post-OAE2 period (O2 ~ 50 μM), Mo accumulation is favored by a large reduction in iron flux. Importantly, this occurs in parallel with oxygenated bottom waters and high rates of aerobic carbon degradation in the surface sediments, implying that elevated Mo burial fluxes in ancient marine facies do not necessarily reflect euxinic or even anoxic conditions within the water column. Our findings suggest that both an increase in production and preservation lead to enrichment in organic carbon in the Western Interior Seaway. More generally, the results demonstrate that a careful consideration of the coupling between iron, carbon and oxygen cycles during the early stages of diagenesis is critical for interpreting geochemical proxies in modern and ancient settings.

Description: Observations and model runs indicate trends in dissolved oxygen (DO) associated with current and ongoing global warming. However, a large-scale observation-to-model comparison has been missing and is presented here. This study presents a first global compilation of DO measurements covering the last 50 yr. It shows declining upper-ocean DO levels in many regions, especially the tropical oceans, whereas areas with increasing trends are found in the subtropics and in some subpolar regions. For the Atlantic Ocean south of 20° N, the DO history could even be extended back to about 70 yr, showing decreasing DO in the subtropical South Atlantic. The global mean DO trend between 50° S and 50° N at 300 dbar for the period 1960 to 2010 is –0.066 μmol kg−1 yr−1. Results of a numerical biogeochemical Earth system model reveal that the magnitude of the observed change is consistent with CO2-induced climate change. However, the pattern correlation between simulated and observed patterns of past DO change is negative, indicating that the model does not correctly reproduce the processes responsible for observed regional oxygen changes in the past 50 yr. A negative pattern correlation is also obtained for model configurations with particularly low and particularly high diapycnal mixing, for a configuration that assumes a CO2-induced enhancement of the C : N ratios of exported organic matter and irrespective of whether climatological or realistic winds from reanalysis products are used to force the model. Depending on the model configuration the 300 dbar DO trend between 50° S and 50° N is −0.027 to –0.047 μmol kg−1 yr−1 for climatological wind forcing, with a much larger range of –0.083 to +0.027 μmol kg−1 yr−1 for different initializations of sensitivity runs with reanalysis wind forcing. Although numerical models reproduce the overall sign and, to some extent, magnitude of observed ocean deoxygenation, this degree of realism does not necessarily apply to simulated regional patterns and the representation of processes involved in their generation. Further analysis of the processes that can explain the discrepancies between observed and modeled DO trends is required to better understand the climate sensitivity of oceanic oxygen fields and predict potential DO changes in the future.

Description: Inorganic dissolved macronutrient (nitrogen, N, and phosphorus, P) supply to surface waters in the eastern tropical South Pacific is influenced by expanding oxygen minimum zones, since N loss occurs due to microbial processes under anoxic conditions while P is increasingly released from the shelf sediments. To investigate the impact of decreasing N:P supply ratios in the Peruvian Upwelling, we conducted nutrient manipulation experiments using a shipboard mesocosm setup with a natural phytoplankton community. In a first experiment, either N or P or no nutrients were added with mesozooplankton present or absent. In a second experiment, initial nutrient concentrations were adjusted to four N:P ratios ranging from 2.5 to 16 using two "high N" and two "high P" levels in combination (i.e., +N, +P, +N and P, no addition). Over six and seven days, respectively, microalgal biomass development as well as nutrient uptake was monitored. Phytoplankton biomass strongly responded to N addition, in both mesozooplankton-grazed and not grazed treatments. The developing diatom bloom in the "high N" exceeded that in the "low N" treatments by a factor of two. No modulation of the total biomass by P-addition was observed, however, species-specific responses were more variable. Notably, some organisms were able to benefit from low N:P fertilization ratios, especially Heterosigma sp. and Phaeocystis globosa which are notorious for forming blooms that are toxic or inadequate for mesozooplankton nutrition. After the decline of the diatom bloom, the relative contribution of unsaturated fatty acid to the lipid content of seston was positively correlated to diatom biomass in the peak bloom, indicating that positive effects of diatom blooms on food quality of the protist community to higher trophic levels remain even after the phytoplankton biomass was incorporated by grazers. Our results indicate an overall N-limitation of the system, especially in the case of dominating diatoms, which were able to immediately utilize the available nitrate (within two days) and develop a biomass maximum within three days of incubation. After the decline of diatom biomass, detection of the cyanobacterial marker pigment aphanizophyll indicated the occurrence of diazotrophs, especially in those enclosures initially provided with high N supply. This was surprising, as diazotrophs are thought to play a role in compensating to some extent the N deficit above OMZs in the succession of phytoplankton after an upwelling event

Description: Transport of liquid and gaseous hydrocarbons through focused fluid flow systems is a widespread process in continental margins and sedimentary basins, which is gaining increased attention in the assessment of geohazards, environment conservation, and securing fossil energy resources. Studying the abundance, distribution and drivers for this process is crucial for understanding its role in 1) the dynamics of gas hydrate accumulation and destabilization, 2) submarine slope stability and related tsunamis, 3) the plethora of chemosynthetic benthic ecosystems that develop in deep seep sites, and 4) the input of greenhouse gases (e.g. methane) into the ocean/atmosphere system, which may influence the atmospheric carbon budget and Earth's paleo- and present climate. New ocean exploration tools provide ever more data and improve our understanding of these systems. However, the subject still suffers from a lack of interdisciplinary knowledge dissemination. The ongoing international debate about the timing and the processes that control fluid expulsion in sedimentary basins is fuelled by their implications for structural and petroleum geology. Because fluids expelled at cold seeps originate at depth they represent open windows into the underlying petroleum systems and are valuable indicators for the reservoir systems. They may also help in deciphering past and predicting future climate change because worldwide release of large amounts of fluids may have an impact on the chemistry of the ocean and atmosphere. Highlights ► Special issue on hydrocarbon leakage through focused fluid flow systems. ► Imaging and interpretation of gas migration and flow structures. ► Polygonal fault systems and their implications on fluid and hydrocarbon migration. ► Ecosystems, methane-derived carbonates and geochemistry of seeps. ► Petroleum systems, thermogenic gas release, and Cenozoic hyper-thermal events.

Description: Anthropogenic CO2 emission will lead to an increase in seawater pCO(2) of up to 80-100 Pa (800-1000 mu atm) within this century and to an acidification of the oceans. Green sea urchins (Strongylocentrotus droebachiensis) occurring in Kattegat experience seasonal hypercapnic and hypoxic conditions already today. Thus, anthropogenic CO2 emissions will add up to existing values and will lead to even higher pCO(2) values 〉200 Pa (〉2000 mu atm). To estimate the green sea urchins' potential to acclimate to acidified seawater, we calculated an energy budget and determined the extracellular acid base status of adult S. droebachiensis exposed to moderately (102-145 Pa, 1007-1431 mu atm) and highly (284-385 Pa, 2800-3800 mu atm) elevated seawater pCO(2) for 10 and 45 days. A 45-day exposure to elevated pCO(2) resulted in a shift in energy budgets, leading to reduced somatic and reproductive growth. Metabolic rates were not significantly affected, but ammonium excretion increased in response to elevated pCO(2). This led to decreased O:N ratios. These findings suggest that protein metabolism is possibly enhanced under elevated pCO(2) in order to support ion homeostasis by increasing net acid extrusion. The perivisceral coelomic fluid acid-base status revealed that S. droebachiensis is able to fully (intermediate pCO(2)) or partially (high pCO(2)) compensate extracellular pH (pH(e)) changes by accumulation of bicarbonate (maximum increases 2.5 mM), albeit at a slower rate than typically observed in other taxa (10-day duration for full pH(e) compensation). At intermediate pCO(2), sea urchins were able to maintain fully compensated pH(e) for 45 days. Sea urchins from the higher pCO(2) treatment could be divided into two groups following medium-term acclimation: one group of experimental animals (29%) contained remnants of food in their digestive system and maintained partially compensated pH(e) (+2.3 mM HCO3-), while the other group (71%) exhibited an empty digestive system and a severe metabolic acidosis (-0.5 pH units, -2.4 mM HCO3-). There was no difference in mortality between the three pCO(2) treatments. The results of this study suggest that S. droebachiensis occurring in the Kattegat might be pre-adapted to hypercapnia due to natural variability in pCO(2) in its habitat. We show for the first time that some echinoderm species can actively compensate extracellular pH. Seawater pCO(2) values of 〉200 Pa, which will occur in the Kattegat within this century during seasonal hypoxic events, can possibly only be endured for a short time period of a few weeks. Increases in anthropogenic CO2 emissions and leakages from potential sub-seabed CO2 storage (CCS) sites thus impose a threat to the ecologically and economically important species S. droebachiensis.

Description: In the European Union (EU), subsidies to the fishing industry and lack of compliance and enforcement of fishing regulations have led to a chronic overcapacity and a general decline of commercial fish stocks. The entire fisheries sector (extractive fishing, fish canning and commercialization subsectors) is still affected, with all directly and indirectly employed people being impacted by the overfishing problem. However, fish populations could strongly increase and generate more economic output if they were left for only a few years under less fishing pressure. The papers published in this Special Issue are the products of recent research conducted by European fisheries scientists, economists, and lawyers. A window of opportunity for change is currently open under the current Common Fisheries Policy (CFP) reform. This Special Issue is an attempt to stimulate the debate by providing new findings and formulating new proposals to rebuild stocks, strengthen ecosystems resilience and better manage EU fisheries. The Special Issue consists of eight papers dealing with relevant biological and economic aspects of the management of European fisheries. Together these papers show that the EU fish stocks are under high fishing pressure and that their recovery will generate not only environmental or ecosystem benefits but also greater profitability for the fisheries sector. Highlights: ► Subsidies, lack of compliance and enforcement have lead to a decline of fish stocks. ► The fisheries sector is affected by the overfishing problem. ► The Special Issue provides valuable papers for the next Common Fisheries Policy reform.

Description: Deep crustal constraint is often carried out using deterministic inverse methods, sometimes using seismic refraction, gravity and electromagnetic datasets in a complementary or "joint" scheme. With increasingly powerful parallel computer systems it is now possible to apply joint inversion schemes to derive an optimum model from diverse input data. These methods are highly effective where the uncertainty in the system is small. However, given the complex nature of these schemes it is often difficult to discern the uniqueness of the output model given the noise in the data, and the application of necessary regularization and weighting in the inversion process means that the extent of user prejudice pertaining to the final result may be unclear. We can rigorously address the subject of uncertainty using standard statistical tools but these methods also become less feasible if the prior model space is large or the forward simulations are computationally expensive. We present a simple Monte Carlo scheme to screen model space in a fully joint fashion, in which we replace the forward simulation with a fast and uncertainty-calibrated mathematical function, or emulator. This emulator is used as a proxy to run the very large number of models necessary to fully explore the plausible model space. We develop the method using a simple synthetic dataset then demonstrate its use on a joint data set comprising first-arrival seismic refraction. MT and scalar gravity data over a diapiric salt body. This study demonstrates both the value of a forward Monte Carlo approach (as distinct from a search-based or conventional inverse approach) in incorporating all kinds of uncertainty in the modelling process, exploring the entire model space, and shows the potential value of applying emulator technology throughout geophysics. Though the target here is relatively shallow, the methodology can be readily extended to address the whole crust.

Description: The Giudicarie fault system represents the central, approximately NE–SW-trending segment of the Periadriatic fault system. Based on new fission track data the near surface evolution of the units bordering the Giudicarie fault system (GFS) is analysed. New and published zircon fission track (ZFT) data are compiled in an age-contour map of the area, and depict some first order features of cooling and exhumation pattern. Out of the three main Permian plutons located in the footwall of the GFS, the northern (Brixen pluton) and southernmost (Kreuzberg pluton) yielded ZFT ages of about 100 Ma, while the intermediate Ifinger pluton cooled through the zircon partial annealing zone only in the Miocene. The Ifinger granodiorite overthrusts the Southalpine basement and the Permian rocks of the Athesian Volcanic District along the NW dipping brittle Naif fault. Across this thrust an important age jump from Miocene to Permian ZFT ages is observed, suggesting that the deformation has jumped towards the southeast, thus deactivating the related segment of the GFS. The most eye-catching feature of the age-contour map is the corridor of young, Miocene ZFT ages from small tonalitic intrusions along the Northern Giudicarie fault. This corridor connects Early Miocene (17–23 Ma) ZFT ages of the NE-Adamello with the Middle–Late Miocene (19–9 Ma) ZFT ages of the Meran–Mauls basement and the western Tauern window and provides evidence for a polyphase deformation along the GFS. A three-step evolution model is proposed for the GFS: (a) shearing of the northern rim of the Adamello batholith along the dextral strike slip Periadriatic fault system; (b) bending of the central part of the fault to a NE direction together with the adjacent intrusive rocks; (c) Dissection of the bend part (Meran–Mauls fault) by the sinistral transpressive Northern Giudicarie fault and exhumation of small tonalitic bodies along this structure. Highlights ► Different exhumation history for Permian intrusions along the Giudicarie fault system. ► Very consistent ZFT ages of ~ 15 Ma for the entire Meran–Mauls basement. ► Corridor of Miocene zircon fission track ages along the Giudicarie fault system. ► Evidence for a polyphase deformation along the Giudicarie fault system.

Description: Dangerous climate change is best avoided by drastically and rapidly reducing greenhouse gas emissions. Nevertheless, geoengineering options are receiving attention on the basis that additional approaches may also be necessary. Here we review the state of knowledge on large-scale ocean fertilization by adding iron or other nutrients, either from external sources or via enhanced ocean mixing. On the basis of small-scale field experiments carried out to date and associated modelling, the maximum benefits of ocean fertilization as a negative emissions technique are likely to be modest in relation to anthropogenic climate forcing. Furthermore, it would be extremely challenging to quantify with acceptable accuracy the carbon removed from circulation on a long term basis, and to adequately monitor unintended impacts over large space and time-scales. These and other technical issues are particularly problematic for the region with greatest theoretical potential for the application of ocean fertilization, the Southern Ocean. Arrangements for the international governance of further field-based research on ocean fertilization are currently being developed, primarily under the London Convention/London Protocol. Highlights: ► Fertilization using iron can increase the uptake of CO2 across the sea surface. ► But most of this uptake is transient; long-term sequestration is difficult to assess. ► Unintended impacts of ocean fertilization may be far removed in space and time. ► For climate benefits, the Southern Ocean has most potential – also most problems. ► A regulatory framework for ocean fertilization research has been developed.

Description: The boron isotope systematics has been determined for azooxanthellate scleractinian corals from a wide range of both deep-sea and shallow-water environments. The aragonitic coral species, Caryophyllia smithii, Desmophyllum dianthus, Enallopsammia rostrata, Lophelia pertusa, and Madrepora oculata, are all found to have relatively high δ11B compositions ranging from 23.2‰ to 28.7‰. These values lie substantially above the pH-dependent inorganic seawater borate equilibrium curve, indicative of strong up-regulation of pH of the internal calcifying fluid (pHcf), being elevated by ∼0.6–0.8 units (ΔpH) relative to ambient seawater. In contrast, the deep-sea calcitic coral Corallium sp. has a significantly lower δ11B composition of 15.5‰, with a corresponding lower ΔpH value of ∼0.3 units, reflecting the importance of mineralogical control on biological pH up-regulation. The solitary coral D. dianthus was sampled over a wide range of seawater pHT and shows an approximate linear correlation with ΔpHDesmo = 6.43 − 0.71pHT (r2 = 0.79). An improved correlation is however found with the closely related parameter of seawater aragonite saturation state, where ΔpHDesmo = 1.09 − 0.14Ωarag (r2 = 0.95), indicating the important control that carbonate saturation state has on calcification. The ability to up-regulate internal pHcf, and consequently Ωcf, of the calcifying fluid is therefore a process present in both azooxanthellate and zooxanthellate aragonitic corals, and is attributed to the action of Ca2+-ATPase in modulating the proton gradient between seawater and the site of calcification. These findings also show that the boron isotopic compositions (δ11Bcarb) of aragonitic corals are highly systematic and consistent with direct uptake of the borate species within the biologically controlled extracellular calcifying medium. We also show that the relatively strong up-regulation of pH and consequent elevation of the internal carbonate saturation state (Ωcf ∼8.5 to ∼13) at the site of calcification by cold-water corals, facilitates calcification at or in some cases below the aragonite saturation horizon, providing a greater ability to adapt to the already low and now decreasing carbonate ion concentrations. Although providing greater resilience to the effects of ocean acidification and enhancing rates of calcification with increasing temperature, the process of internal pHcf up-regulation has an associated energetic cost, and therefore growth-rate cost, of ∼10% per 0.1 pH unit decrease in seawater pHT. Furthermore, as the aragonite saturation horizon shoals with rapidly increasing pCO2 and Ωarag 〈 1, increased dissolution of the exposed skeleton will ultimately limit their survival in the deep oceans.

Description: A 2-Dimensional mathematical reaction-transport model was developed to study the impact of the mud-dwelling frenulate tubeworm Siboglinum sp. on the biogeochemistry of a sediment (MUC15) at the Captain Arutyunov mud volcano (CAMV). By explicitly describing the worm in its surrounding sediment, we are able to make budgets of processes occurring in- or outside of the worm, and to quantify how different worm densities and biomasses affect the anaerobic oxidation of methane (AOM) and sulfide reoxidation (HSox). The model shows that, at the observed densities, the presence of a thin worm body is sufficient to keep the upper 10 cm of sediment well homogenised with respect to dissolved substances, in agreement with observations. By this "bio-ventilation" activity, the worm pushes the sulfate-methane transition (SMT) zone downward to the posterior end of its body, and simultaneously physically separates the sulfide produced during the anaerobic oxidation of methane from oxygen. While there is little scope for AOM to take place in the tubeworm's body, 70% of the sulfide that is produced by sulfate reduction processes or that is advected in the sediment is preferentially shunted via the organism where it is oxidised by endosymbionts providing the energy for the worm's growth. The process of sulfide reoxidation, occurring predominantly in the worm's body is thus very distinct from the anaerobic oxidation of methane, which is a diffuse process that takes place in the sediments in the methane-sulfate transition zone. We show how the sulfide oxidation process is affected by increasing densities and length of the frenulates, and by upward advection velocity. Our biogeochemical model is one of the first to describe tubeworms explicitly. It can be used to directly link biological and biogeochemical observations at seep sites, and to study the impacts of mud-dwelling frenulates on the sediment biogeochemistry under varying environmental conditions. Also, it provides a tool to explore the competition between bacteria and fauna for available energy resources.

Description: The risk and environmental impact assessments required for geological CO2 storage projects will have to rely on different types of numerical models, which will have to be calibrated and validated against measurements. Available measurements from ongoing demonstration projects are limited, hence it is necessary to turn to analog processes or laboratory experiments to estimate model parameters. In any case, parameter estimates will have uncertainties that will be important to assess when predicting future scenarios. We study a model for the rise velocity of droplets in the ocean, an important process sub-model for simulating gas seeps into marine waters. As the origin we use the parameters estimation study by Bigalke et al. (2010) based on a tank experiment. We illustrate how Linearized Covariance Analysis (LCA) can be used to assess the parameter uncertainties, and how to design a similar experiment that reduces these uncertainties. The linearity assumption underlying LCA is assessed using curvature measures. It is shown that up to ∼63% reduction in uncertainties is achieved by choosing the right droplet size distribution; by extending the range of droplet sizes to include larger droplets the uncertainties are reduced by another ∼88%.

Description: Magnesium calcites were synthesized from aqueous solutions supersaturated with respect to calcite at 25, 40, 60, and 80 °C in gas tight batch reactors for up to 35 days. Any amorphous material still present in the precipitates was removed using a partial dissolution treatment. Resulting purified Mg-calcite had Mg contents ranging from 6 to 32 mol% MgCO3. An isotopic steady-state was attained between the fluid and the precipitated solids within two weeks at 25 °C. δ18O values derived from the experiments at steady-state, depend on both temperature and the Mg content of the calcite in accord with: 1000lnαMg-calcite–H2O=18,030/T−32.42+(6×108/T3–5.47×106/T2+16,780/T−17.21)×CMg where αMg-calcite–H2O represents the calcite–water oxygen isotope fractionation factor, T refers to the temperature in °K and CMg denotes the mole percent of MgCO3 in the calcite. These results indicate that the addition of 5 mol% MgCO3 into the calcite increases 1000lnαMg-calcite–H2O by 0.88 as compared to that of pure calcite at 25 °C. This difference could lead to a 4.2 °C decrease in estimated formation temperature estimates. These results demonstrate that the accurate interpretation of oxygen isotope fractionation in magnesium calcites requires explicit provision for the effect of magnesium on oxygen isotope fractionation factors. Highlights ► The effect of Mg on calcite–aqueous fluid oxygen isotope fractionation was investigated. ► Mg incorporation is increasing the calcite–aqueous fluid oxygen isotope fractionation. ► This effect is reduced at higher temperatures. ► Obtained results are important for paleo-temperature estimation. Gadget timed out while loading

Description: Seismic oceanography is based on the passage of a regularly repeating acoustic impulsive source and an acquisition streamer along the surface of the ocean, and on summing together all signals reflected from temperature and salinity interfaces in the ocean (where there are acoustic impedance contrasts). Due to the inherent redundancy of the method, random noise is attenuated, while signal is preserved; however, if the original signal-to-noise ratio is large enough, one need not use data from the entire streamer to create a 2D profile. A processing scheme is here devised to obtain consecutive images, known as stacks, of the structure of the water column. The scheme, named Seismic Offset Groups (SOG), consists in splitting the data from the whole streamer at a given geographical position into data produced by different streamer subsets. The method is illustrated by partitioning data from a 5-km long streamer into 7 offset groups separated by 3.5 min in time, thereby imaging the same seafloor-referenced location over a period of 21 min. As the streamer passes over a fixed geographical point, motions within the water column are observed. Each stack, created with a subset of the complete streamer, can therefore be considered an image of the water column at a particular time step (animation frame). In this way each image shows a different thermohaline fabric and the animation allows us to visualize internal ocean motions.

Description: On 27 February 2010 the Mw 8.8 Maule earthquake in Central Chile ruptured a seismic gap where significant strain had accumulated since 1835. Shortly after the mainshock a dense network of temporary seismic stations was installed along the whole rupture zone in order to capture the aftershock activity. Here, we present the aftershock distribution and first motion polarity focal mechanisms based on automatic detection algorithms and picking engines. By processing the seismic data between 15 March and 30 September 2010 from stations from IRIS, IPGP, GFZ and University of Liverpool we determined 20,205 hypocentres with magnitudes Mw between 1 and 5.5. Seismic activity occurs in six groups: 1.) Normal faulting outer rise events 2.) A shallow group of plate interface seismicity apparent at 25–35 km depth and 50–120 km distance to the trench with some variations between profiles. Along strike, the aftershocks occur largely within the zone of coseismic slip but extend ~ 50 km further north, and with predominantly shallowly dipping thrust mechanisms. Along dip, the events are either within the zone of coseismic slip, or downdip from it, depending on the coseismic slip model used. 3.) A third band of seismicity is observed further downdip at 40–50 km depth and further inland at 150–160 km trench perpendicular distance, with mostly shallow dipping (~ 28°) thrust focal mechanisms indicating rupture of the plate interface significantly downdip of the coseismic rupture, and presumably above the intersection of the continental Moho with the plate interface. 4.) A deep group of intermediate depth events between 80 and 120 km depth is present north of 36°S. Within the Maule segment, a large portion of events during the inter-seismic phase originated from this depth range. 5.) The magmatic arc exhibits a small amount of crustal seismicity but does not appear to show significantly enhanced activity after the Mw 8.8 Maule 2010 earthquake. 6.) Pronounced crustal aftershock activity with mainly normal faulting mechanisms is found in the region of Pichilemu (~ 34.5°S). These crustal events occur in a ~ 30 km wide region with sharp inclined boundaries and oriented oblique to the trench. The best-located events describe a plane dipping to the southwest, consistent with one of the focal planes of the large normal-faulting aftershock (Mw = 6.9) on 11 March 2010.

Description: The south-central Chilean subduction zone has witnessed some of the largest earthquakes in history, making this region particularly important for understanding plate coupling. Here we present the results of a local earthquake tomography study from a temporary local seismic network in the Villarrica region between 39 and 40°S, where the largest coseismic displacement of the 1960 Valdivia earthquake occurred. A lowvelocity anomaly and high Vp/Vs values occur under the coastal region, indicating mantle serpentinisation and/or underthrusting of forearc material. Further east, a high-velocity anomaly is observed, interpreted as “normal” high-velocity mantle. Under the active volcanic arc a low-velocity anomaly together with high Vp/Vs ratios (1.8 and higher) likely images fluid ascent beneath the volcanoes. Close to the subducting Valdivia Fracture Zone, the coastal low-velocity anomaly extends further inland, where it interrupts and shifts the high-velocity anomalies associated with “normal” fast mantle velocities. This may indicate enhanced fluid presence along this part of the margin, probably caused by a stronger hydration of the incoming plate along the Valdivia Fracture Zone. This is consistent with geochemical fluid proxies (U/Th, Pb/Ce, Ba/Nb) in young volcanic rocks displaying peak values along the volcanic front at Llaima and Villarrica Volcanoes, and with recent GPS measurements, which suggested a local reduction in plate coupling in this region. The shift in the high-velocity anomaly underlying the central part may be caused by a north to south decrease in plate age and hydration across the Valdivia Fracture Zone, and may explain why a Central Valley is absent in this segment of the margin. The low La/Yb ratios in the volcanic rocks from Villarrica and Llaima suggest that the high slab-derived fluid flux causes elevated degrees of melting beneath these volcanoes, providing an explanation as to why these are amongst the most active volcanoes in South America.

Description: In the aftermath of an earthquake and tsunami on 11 March 2011 radioactive 137Cs was discharged from a damaged nuclear power plant to the sea off Fukushima Dai-ichi, Japan. Here we explore its dilution and fate with a state-of-the-art global ocean general circulation model, which is eddy-resolving in the region of interest. We find apparent consistency between our simulated circulation, estimates of 137Cs discharged ranging from 0.94 p Bq (Japanese Government, 2011) to 3.5 ± 0.7 p Bq (Tsumune et al., 2012), and measurements by Japanese authorities and the power plant operator. In contrast, our simulations are apparently inconsistent with the high 27 ± 15 p Bq discharge estimate of Bailly du Bois et al. (2012). Expressed in terms of a diffusivity we diagnose, from our simulations, an initial dilution on the shelf of 60 to 100 m2 s−1. The cross-shelf diffusivity is at 500 ± 300 m2 s−1 significantly higher and variable in time as indicated by its uncertainty. Expressed as an effective residence time of surface water on the shelf, the latter estimate transfers to 43 ± 16 days. As regards the fate of 137Cs, our simulations suggest that activities up to 4 mBq l−1 prevail in the Kuroshio-Oyashio Interfrontal Zone one year after the accident. This allows for low but detectable 0.1 to 0.3 m Bq l−1 entering the North Pacific Intermediate Water before the 137Cs signal is flushed away. The latter estimates concern the direct release to the sea only.

Description: The coelacanth, Latimeria chalumnae, occurs at the Eastern coast of Africa from South Africa up to Kenya. It is often referred to as a living fossil mainly because of its nearly unchanged morphology since the Middle Devonian. As it is a close relative to the last common ancestor of fish and tetrapods, molecular studies mostly focussed on their phylogenetic relationships. We now present a population genetic study based on 71 adults from the whole known range of the species. Despite an overall low genetic diversity, there is evidence for divergence of local populations. We assume that originally the coelacanths at the East African Coast derived from the Comoros population, but have since then diversified into additional independent populations: one in South Africa and another in Tanzania. Unexpectedly, we find a split of the Comoran coelacanths into two sympatric subpopulations. Despite its undeniably slow evolutionary rate, the coelacanth still diversifies and is therefore able to adapt to new environmental conditions.

Description: Hydrocarbon seeps are ubiquitous at gas-prone Cenozoic deltas such as the Nile Deep Sea Fan (NDSF2) where seepage into the bottom water has been observed at several mud volcanoes (MVs3) including North Alex MV (NAMV4). Here we investigated the sources of hydrocarbon gases and sedimentary organic matter together with biomarkers of microbial activity at four locations of NAMV to constrain how venting at the seafloor relates to the generation of hydrocarbon gases in deeper sediments. At the centre, high upward flux of hot (70 °C) hydrocarbon-rich fluids is indicated by an absence of biomarkers of Anaerobic Oxidation of Methane (AOM) and nearly constant methane (CH4) concentration depth-profile. The presence of lipids of incompatible thermal maturities points to mixing between early-mature petroleum and immature organic matter, indicating that shallow mud has been mobilized by the influx of deep-sourced hydrocarbon-rich fluids. Methane is enriched in the heavier isotopes, with values of δ13C∼−46.6‰VPDB and δD ∼−228‰VSMOW, and is associated with high amounts of heavier homologues (C2+) suggesting a co-genetic origin with the petroleum. On the contrary at the periphery, a lower but sustained CH4 flux is indicated by deeper sulphate–methane transition zones and the presence of 13C-depleted biomarkers of AOM, consistent with predominantly immature organic matter. Values of δ13C-CH4∼−60‰VPDB and decreased concentrations of 13C-enriched C2+ are typical of mixed microbial CH4 and biodegraded thermogenic gas from Plio-Pleistocene reservoirs of the region. The maturity of gas condensate migrated from pre-Miocene sources into Miocene reservoirs of the Western NDSF is higher than that of the gas vented at the centre of NAMV, supporting the hypothesis that it is rather released from the degradation of oil in Neogene reservoirs. Combined with the finding of hot pore water and petroleum at the centre, our results suggest that clay mineral dehydration of Neogene sediments, which takes place posterior to reservoir filling, may contribute to intense gas generation at high sedimentation rate deltas. Highlights ► Extensive seepage of biodegraded gas at the periphery of North Alex mud volcano. ► At the centre seepage of deeper-sourced hot water, oil and thermogenic gas. ► At the centre, degradation of reservoired-oil to gas is most likely. ► Multivariate statistics on biomarkers show oil degradation at the centre and AOM at the periphery. ► Shallow gas production is enhanced by hot water influx from actively dewatering clays.

Description: We employed coupled 3-D biophysical models to better understand the effects of physical forcing conditions as well as differences in vertical distribution and growth performance on the spatial distribution of larval sprat (Sprattus sprattus) in the North and the Baltic Sea. Our model simulations analysed the influence of abiotic and biotic forcing variability on larval transport and the seasonal and inter-annual variability in spatial distribution of larvae originating from different spawning areas in each of the two systems. Due to strong spatial and temporal differences in temperature, drift durations differed between the two ecosystems. During cold spring and warm summer periods, drift durations in the Baltic were ∼35 and 15 days, respectively, but were somewhat shorter (30 and 10 d) in the North Sea. Changes in larval feeding rates markedly impacted larval growth rate and stage duration, and, hence, environmental histories experienced by larvae as well as their final distribution. Generally, specific spawning sites were relatively well connected to specific juvenile nursery areas in the Baltic. However, in the North Sea, considerable mixing of sprat populations occurred with frontal areas acted as convergence zones for older larvae originating from different spawning sites. The mixing and/or co-occurrence of 18-mm larvae from different source regions were greatest (least) in the early spring (summer) for larvae at colder (warmer) temperatures having longer (shorter) drift durations. Generally, such high mixing probability would not promote small- or medium-scale population distinctness of North Sea sprat. The results of our coupled hydrodynamic/trophodynamic model simulations provide a baseline in quantifying and understanding larval sprat transport in these different ecosystems and exemplify the extent to which environmental variability (e.g., differences in temperature as well as prey availability) can influence spatial distributions of larval fish.

Description: The radiogenic isotope composition of the Rare Earth Element (REE) neodymium (Nd) is a powerful water mass proxy for present and past ocean circulation. The processes controlling the Nd budget of the global ocean are not quantitatively understood and in particular source and sink mechanisms are still under debate. In this study we present the first full water column data set of dissolved Nd isotope compositions and Nd concentrations for the Eastern Equatorial Pacific (EEP), where one of the globally largest Oxygen Minimum Zones (OMZ) is located. This region is of particular interest for understanding the biogeochemical cycling of REEs because anoxic conditions may lead to release of REEs from the shelf, whereas high particle densities and fluxes potentially remove the REEs from the water column. Data were obtained between 1°40′N and 16°S along a nearshore and an offshore transect. Near surface zonal current bands, such as the Equatorial Undercurrent (EUC) and the Subsurface Countercurrent (SSCC), which are supplying oxygen-rich water to the OMZ are characterized by radiogenic Nd isotope signatures (εNd=−2). Surface waters in the northernmost part of the study area are even more radiogenic (εNd=+3), most likely due to release of Nd from volcanogenic material. Deep and bottom waters at the southernmost offshore station (14°S) are clearly controlled by advection of water masses with less radiogenic signatures (εNd=−7) originating from the Southern Ocean. Towards the equator, however, the deep waters show a clear trend towards more radiogenic values of up to εNd=−2. The northernmost station located in the Panama basin shows highly radiogenic Nd isotope signatures in the entire water column, which indicates that particle scavenging, downward transport and release processes play an important role. This is supported by relatively low Nd concentrations in deep waters (3000–6000 m) in the EEP (20 pmol/kg) compared to locations in the Northern and Central Pacific (40–60 pmol/kg), which suggests enhanced removal of Nd in the EEP.

Description: The biomarker composition of dissolved organic carbon (DOC) of the six largest Arctic rivers was studied between 2003 and 2007 as part of the PARTNERS Project. Samples were collected over seasonal cycles relatively close to the river mouths. Here we report the lignin phenol and p-hydroxybenzene composition of Arctic river DOC in order to identify major sources of carbon. Arctic river DOC represents an important carbon conduit linking the large pools of organic carbon in the Arctic/Subarctic watersheds to the Arctic Ocean. Most of the annual lignin discharge (〉75%) occurs during the two month of spring freshet with extremely high lignin concentrations and a lignin phenol composition indicative of fresh vegetation from boreal forests. The three large Siberian rivers, Lena, Yenisei, and Ob, which also have the highest proportion of forests within their watersheds, contribute about 90% of the total lignin discharge to the Arctic Ocean. The composition of river DOC is also characterized by elevated levels of p-hydroxybenzenes, particularly during the low flow season, which indicates a larger contribution from mosses and peat bogs. The lignin composition was strongly related to the average 14C-age of DOC supporting the abundance of young, boreal-vegetation-derived leachates during spring flood, and older, soil-, peat-, and wetland-derived DOC during groundwater dominated low flow conditions, particularly in the Ob and Yukon Rivers. We observed significant differences in DOC concentration and composition between the rivers over the seasonal cycles with the Mackenzie River being the most unique, the Lena River being similar to the Yenisei, and the Yukon being most similar to the Ob. The observed relationship between the lignin phenol composition and watershed characteristics suggests that DOC discharge from these rivers could increase in a warmer climate under otherwise undisturbed conditions.

Description: The global Late Pliocene/Early Pleistocene cooling (~3.0–2.0 million years ago – Ma) concurred with extremely high diatom and biogenic opal production in most of the major coastal upwelling regions. This phenomenon was particularly pronounced in the Benguela upwelling system (BUS), off Namibia, where it is known as the Matuyama Diatom Maximum (MDM). Our study focuses on a new diatom silicon isotope (δ30Si) record covering the MDM in the BUS. Unexpectedly, the variations in δ30Si signal follow biogenic opal content, whereby the highest δ30Si values correspond to the highest biogenic opal content. We interpret the higher δ30Si values during the MDM as a result of a stronger degree of silicate utilisation in the surface waters caused by high productivity of mat-forming diatom species. This was most likely promoted by weak upwelling intensity dominating the BUS during the Late Pliocene/Early Pleistocene cooling combined with a large silicate supply derived from a strong Southern Ocean nutrient leakage responding to the expansion of Antarctic ice cover and the resulting stratification of the polar ocean 3.0–2.7 Ma ago. A similar scenario is hypothesized for other major coastal upwelling systems (e.g. off California) during this time interval, suggesting that the efficiency of the biological carbon pump was probably sufficiently enhanced in these regions during the MDM to have significantly increased the transport of atmospheric CO2 to the deep ocean. In addition, the coeval extension of the area of surface water stratification in both the Southern Ocean and the North Pacific, which decreased CO2 release to the atmosphere, led to further enhanced atmospheric CO2 drawn-down and thus contributed significantly to Late Pliocene/Early Pleistocene cooling.

Description: We present the first systematic study of the silicon isotope composition in the water column (δ30SiSi(OH)4) and in diatoms (δ30Sidiatom) from the underlying surface sediments in a coastal upwelling region. The surface waters upwelling on the shelf off Peru are mainly fed by southward flowing subsurface waters along the coast, which show a mean δ30SiSi(OH)4 of +1.5‰. The concentration of dissolved silicic acid (Si(OH)4) increases towards the south in these waters and with increasing water depth, suggesting lateral mixing with water masses from the south and intense remineralisation of particulate biogenic silica (bSiO2) in the water column and in the surface sediments. Surface waters in the realm of the most intense upwelling between 5°S and 15°S have only marginally elevated δ30SiSi(OH)4 values (δ30SiSi(OH)4 = +1.7‰) with respect to the source Si isotope composition, whereas further north and south, where upwelling is less pronounced, surface waters are more strongly fractionated (δ30SiSi(OH)4 up to +2.8‰) due to the stronger utilisation of the smaller amounts of available Si(OH)4. The degree of Si(OH)4 utilisation in the surface waters along the shelf estimated from the Si(OH)4 concentration data ranges from 51% to 93%. The δ30Sidiatom values of hand-picked diatoms in the underlying surface sediments vary from +0.6‰ to +2.0‰, which is within the range of the expected fractionation between surface waters and diatoms. The fractionation signal in the surface waters produced during formation of the diatoms is reflected by the δ30Sidiatom values in the underlying sediments, with the lowest δ30Sidiatom values in the main upwelling region. The silicon isotope compositions of bSiO2 (δ30SibSiO2) from the same surface sediment samples are generally much lower than the δ30Sidiatom signatures indicating a significant contamination of the bSiO2 with biogenic siliceous material other than diatoms, such as sponge spicules. This shift towards lighter δ30SibSiO2 values by up to −1.3‰ compared to δ30Sidiatom signatures for the same surface sediment samples potentially biases the interpretation of δ30Si paleorecords from sediments with low bSiO2 concentrations, and thus the reconstruction of past Si(OH)4 utilisation in surface waters.

Description: Calcareous foraminifera are well known for their CaCO3 shells. Yet, CaCO3 precipitation acidifies the calcifying fluid. Calcification without pH regulation would therefore rapidly create a negative feedback for CaCO3 precipitation. In unicellular organisms, like foraminifera, an effective mechanism to counteract this acidification could be the externalization of H+ from the site of calcification. In this study we show that a benthic symbiont-free foraminifer Ammonia sp. actively decreases pH within its extracellular microenvironment only while precipitating calcite. During chamber formation events the strongest pH decreases occurred in the vicinity of a newly forming chamber (range of gradient similar to 100 mu m) with a recorded minimum of 6.31 (〈10 mu m from the shell) and a maximum duration of 7 h. The acidification was actively regulated by the foraminifera and correlated with shell diameters, indicating that the amount of protons removed during calcification is directly related to the volume of calcite precipitated. The here presented findings imply that H+ expulsion as a result of calcification may be a wider strategy for maintaining pH homeostasis in unicellular calcifying organisms

Description: Density changes in the upper water column of the northern North Atlantic may enhance or reduce vertical convection of surface water with profound effects on meridional overturning and climate in the wider region. This study tests the capability of paired delta O-18 values of two planktonic foraminiferal species - Neogloboquadrina pachyderma (s) and Turborotalita quinqueloba - for the reconstruction of near-surface density stratification in high latitudes or the glacial ocean. Foraminiferal data from two sediment cores of crucial areas of the Nordic Seas were compared with insolation-induced thermal stratification changes as obtained by simulations with the general circulation model ECHO-G. The comparison suggests that insolation was the chief mechanism to change thermocline strength during most of the Holocene. Prior to that, stratification depended by and large on the varying amounts of meltwater injected at the sea surface. Similar to the modern central Arctic Ocean, a pronounced and thick halocline prevented surface waters from deep convection in the central Nordic Seas. Parts of the Norwegian Sea, however, were also stratified but more analogous to the modern Greenland Sea, where deep convection can occur in late winter as a result of the density increase upon a combination of cold temperatures and wind stress. Our findings thus support previous results of an active meridional overturning also in a glacial ocean.

Description: This paper is devoted to a study on the effects of different parameterisations of vertical turbulence – with a 3D hydrodynamic model COHERENS – on the accuracy of calculated temperature and salinity fields in a hydrodynamically complex test area – the Baltic Sea, Gulf of Finland. Two algebraic parameterisations and k–ε and k-models were used. For k-model four different sets of stability functions were used. Calculated vertical profiles of temperature and salinity were compared against CTD-profiles collected during a measurement campaign in the Gulf of Finland in summer 1996. The dataset has an outstanding spatial and temporal coverage including over 300 measured CTD profiles. The thermocline depth was underestimated throughout summer by all the vertical turbulence schemes. The selection of stability functions had significant effect on the accuracy of the k-model. Generally k-model performed better when the limiting conditions for mixing length were not applied. The k-model with stability functions based on the Munk–Anderson relation without limiting condition for mixing length showed best accuracy in the calculated profiles of temperature and in the thermocline depth. The improvement of the meteorological forcing had an impact on the exactness of the calculated thermocline depth. However, sensitivity tests showed that this impact was relatively small. Generally, calculated salinity was overestimated in the surface layer and underestimated in the bottom layers. Algebraic parameterisations had highest accuracy in the vertical salinity profiles. In the eastern Gulf of Finland the calculated values of salinity were overestimated. The accuracy of initial conditions, river runoff and bathymetry had significant effect on the accuracy of calculated salinity fields. Highlights: We studied the performance of the vertical turbulence parameterisations in the modeling of hydrodynamics in the Baltic Sea. ► We compared the calculated temperature and salinity fields against dataset having outstanding temporal and spatial coverage. ► The vertical turbulence parameterisations showed considerable differences in the accuracy of the calculated temperature. ► The mixed layer depth was underestimated by all vertical turbulence schemes used in this study. ► Selection of stability functions had significant effect on the accuracy of the turbulence closure schemes.

Description: Oxygen-deficient waters in the ocean, generally referred to as oxygen minimum zones (OMZ), are expected to expand as a consequence of global climate change. Poor oxygenation is promoting microbial loss of inorganic nitrogen (N) and increasing release of sediment-bound phosphate (P) into the water column. These intermediate water masses, nutrient-loaded but with an N deficit relative to the canonical N:P Redfield ratio of 16:1, are transported via coastal upwelling into the euphotic zone. To test the impact of nutrient supply and nutrient stoichiometry on production, partitioning and elemental composition of dissolved (DOC, DON, DOP) and particulate (POC, PON, POP) organic matter, three nutrient enrichment experiments were conducted with natural microbial communities in shipboard mesocosms, during research cruises in the tropical waters of the southeast Pacific and the northeast Atlantic. Maximum accumulation of POC and PON was observed under high N supply conditions, indicating that primary production was controlled by N availability. The stoichiometry of microbial biomass was unaffected by nutrient N:P supply during exponential growth under nutrient saturation, while it was highly variable under conditions of nutrient limitation and closely correlated to the N:P supply ratio, although PON:POP of accumulated biomass generally exceeded the supply ratio. Microbial N:P composition was constrained by a general lower limit of 5:1. Channelling of assimilated P into DOP appears to be the mechanism responsible for the consistent offset of cellular stoichiometry relative to inorganic nutrient supply and nutrient drawdown, as DOP build-up was observed to intensify under decreasing N:P supply. Low nutrient N:P conditions in coastal upwelling areas overlying O2-deficient waters seem to represent a net source for DOP, which may stimulate growth of diazotrophic phytoplankton. These results demonstrate that microbial nutrient assimilation and partitioning of organic matter between the particulate and the dissolved phase are controlled by the N:P ratio of upwelled nutrients, implying substantial consequences for nutrient cycling and organic matter pools in the course of decreasing nutrient N:P stoichiometry.

Description: The warm and saline North Atlantic inflow to the Arctic Ocean is a major component of high northern latitude circulation and the main mechanism of deep water renewal in the Arctic Ocean. Knowledge of its past variability is critical for understanding the high latitude feedback mechanisms of the climate system. Here we present the first combined seawater Hf and Nd isotope compositions of past Arctic Intermediate Water extracted from the authigenic Fe–Mn oxyhydroxide fraction of two sediment cores recovered near the North Pole, to reconstruct changes in contributions from glacial brines of the Eurasian shelf and past inflow of Atlantic waters. The Hf and Nd isotopic compositions obtained from leachates of the authigenic fraction show closely coupled and environmentally controlled variations over the past 14 million years. An observed offset of these data from seawater εHf and εNd compositions from other ocean basins (seawater array) is interpreted as the result of continuously prevailing glacial weathering conditions on the high latitude Eurasian continent. In the late Quaternary, large amplitude Hf and Nd isotopic variations of Arctic Intermediate Water (AIW) was characterized by more radiogenic isotope signatures generally prevailing under glacial conditions and less radiogenic values during interglacial periods. On the basis of the close coupling between Nd and Hf isotopes, we suggest that the evolution of Hf isotope compositions of central Arctic AIW has primarily been controlled by changes in ocean circulation and provenance of weathering inputs, rather than changes in weathering regime.

Description: Oceanic emissions of halogenated very short-lived substances (VSLS) are expected to contribute significantly to the stratospheric halogen loading and therefore to ozone depletion. The amount of VSLS transported into the stratosphere is estimated based on in-situ observations around the tropical tropopause layer (TTL) and on modeling studies which mostly use prescribed global emission scenarios to reproduce observed atmospheric concentrations. In addition to upper-air VSLS measurements, direct observations of oceanic VSLS emissions are available along ship cruise tracks. Here we use such in-situ observations of VSLS emissions from the West Pacific and tropical Atlantic together with an atmospheric Lagrangian transport model to estimate the direct contribution of bromoform (CHBr3), and dibromomethane (CH2Br2) to the stratospheric bromine loading as well as their ozone depletion potential. Our emission-based estimates of VSLS profiles are compared to upper-air observations and thus link observed oceanic emissions and in situ TTL measurements. This comparison determines how VSLS emissions and transport in the cruise track regions contribute to global upper-air VSLS estimates. The West Pacific emission-based profiles and the global upper-air observations of CHBr3 show a relatively good agreement indicating that emissions from the West Pacific provide an average contribution to the global CHBr3 budget. The tropical Atlantic, although also being a CHBr3 source region, is of less importance for global upper-air CHBr3 estimates as revealed by the small emission-based abundances in the TTL. Western Pacific CH2Br2 emission-based estimates are considerably smaller than upper-air observations as a result of the relatively low sea-to-air flux found in the West Pacific. Together, CHBr3 and CH2Br2 emissions from the West Pacific are projected to contribute to the stratospheric bromine budget with 0.4 pptv Br on average and 2.3 pptv Br for cases of maximum emissions through product and source gas injection. These relatively low estimates reveal that the tropical West Pacific, although characterized by strong convective transport, might overall contribute less VSLS to the stratospheric bromine budget than other regions as a result of only low CH2Br2 and moderate CHBr3 oceanic emissions.

Description: Hydrocarbon-rich fluids expelled at mud volcanoes (MVs) may contribute significantly to the carbon budget of the oceans, but little is known about the long-term variation in fluid fluxes at MVs. The Darwin MV is one of more than 40 MVs located in the Gulf of Cadiz, but it is unique in that its summit is covered by a thick carbonate crust that has the potential to provide a temporal record of seepage activity. In order to test this idea, we have conducted petrographic, chemical and isotopic analyses of the carbonate crust. In addition a 1-D transport-reaction model was applied to pore fluid data to assess fluid flow and carbonate precipitation at present. The carbonate crusts mainly comprise of aragonite, with a chaotic fabric exhibiting different generations of cementation and brecciation. The crusts consist of bioclasts and lithoclasts (peloids, intraclasts and extraclasts) immersed in a micrite matrix and in a variety of cement types (microsparite, botryoidal, isopachous acicular, radial and splayed fibrous). The carbonates are moderately depleted in 13C (δ13C = − 8.1 to − 27.9‰) as are the pore fluids (δ13C = − 19.1 to − 28.7‰), which suggests that their carbon originated from the oxidation of methane and higher hydrocarbons, like the gases that seep from the MV today. The carbonate δ18O values are as high as 5.1‰, and it is most likely that the crusts formed from 18O-rich fluids derived from dehydration of clay minerals at depth. Pore fluid modelling results indicate that the Darwin MV is currently in a nearly dormant phase (seepage velocities are 〈 0.09 cm yr− 1). Thus, the thick carbonate crust must have formed during past episodes of high fluid flow, alternating with phases of mud extrusion and uplift. Highlights ► Results of pore fluid modelling indicate low seepage activity at localised sites. ► Pore fluids are supersaturated with respect to hydrocarbons of thermogenic origin. ► AOM supports vent fauna and results in the formation of authigenic carbonates. ► The carbonate crust has a brecciated appearance and mainly consists of aragonite. ► The crust formation seems to be regulated by changes in fluid and mudflow activity.

Description: Large sedimentary deposits consisting of several major contourite drifts were studied by means of high-resolution multichannel seismic data at the middle slope along the Northern Argentina Continental Margin to determine their evolutionary stages as well as to identify and assess the possible impact of Northern Source Deep Water (NSDW) on the slope architecture. The imaged contouritic sediments allow decoding on the regional paleo-oceanographic setting of the last 32 Ma. Earliest contouritic sedimentation can be observed close to the Eocene/Oligocene boundary based on an aggradational stacking pattern with a complex and wavy seismic facies, pointing toward a hydrodynamically turbulent flow pattern. This facies is most likely related to the opening of the Drake Passage associated with global cooling and a strengthening of surface, intermediate and deep ocean currents in the Southern Ocean. During the Middle Miocene plastered drift sequences with an aggradational reflection pattern were deposited. Their depositional style indicates weak, non-turbulent current conditions, which are interpreted to be related to a vertical shift of water mass interfaces caused by the first formation of NSDW during the Mid-Miocene climatic optimum. On top, the formation of plastered drift sequences led to the modern extent of the Ewing Terrace, which was probably controlled by the continuous strengthening and thickening of NSDW until the final closure of the Central American Seaway (CAS). During the Pliocene and Quaternary, after the complete closure of the CAS and under the influence of the full force of the NSDW, mounded plastered drift sequences are built upon the Ewing Terrace generating the modern slope morphology. Therefore, we suggest that deep-water production in the northern hemisphere plays a significant role by controlling the shape of the continental slopes in the southwestern South Atlantic since the Middle Miocene. Highlights ► Slope of northern Argentine Continental margin is current controlled since 32 Ma. ► Variability of Northern Source Deep Water (NSDW) controls sedimentary processes. ► Sedimentary processes are susceptible to changes of the Brazil-Malvinas Confluence. ► Impact of NSDW on slope processes is underestimated in the southern hemisphere.

Description: In this study we present an initial dataset of Mn/Ca and Fe/Ca ratios in tests of benthic foraminifera from the Peruvian oxygen minimum zone (OMZ) determined with SIMS. These results are a contribution to a better understanding of the proxy potential of these elemental ratios for ambient redox conditions. Foraminiferal tests are often contaminated by diagenetic coatings, like Mn rich carbonate- or Fe and Mn rich (oxyhydr)oxide coatings. Thus, it is substantial to assure that the cleaning protocols are efficient or that spots chosen for microanalyses are free of contaminants. Prior to the determination of the element/Ca ratios, the distributions of several elements (Ca, Mn, Fe, Mg, Ba, Al, Si, P and S) in tests of the shallow infaunal species Uvigerina peregrina and Bolivina spissa were mapped with an electron microprobe (EMP). To visualize the effects of cleaning protocols uncleaned and cleaned specimens were compared. The cleaning protocol included an oxidative cleaning step. An Fe rich phase was found on the inner test surface of uncleaned U. peregrina specimens. This phase was also enriched in Al, Si, P and S. A similar Fe rich phase was found at the inner test surface of B. spissa. Specimens of both species treated with oxidative cleaning show the absence of this phase. Neither in B. spissa nor in U. peregrina were any hints found for diagenetic (oxyhydr)oxide or carbonate coatings. Mn/Ca and Fe/Ca ratios of single specimens of B. spissa from different locations have been determined by secondary ion mass spectrometry (SIMS). Bulk analyses using solution ICP-MS of several samples were compared to the SIMS data. The difference between SIMS analyses and ICP-MS bulk analyses from the same sampling sites was 14.0–134.8 μmol mol−1 for the Fe/Ca and 1.68(±0.41) μmol mol−1 for the Mn/Ca ratios. This is in the same order of magnitude as the variability inside single specimens determined with SIMS at these sampling sites (1σ[Mn/Ca] = 0.35–2.07 μmol mol−1; 1σ[Fe/Ca] = 93.9–188.4 μmol mol−1). The Mn/Ca ratios in the calcite were generally relatively low (2.21–9.93 μmol mol−1) but in the same magnitude and proportional to the surrounding pore waters (1.37–6.67 μmol mol−1). However, the Fe/Ca ratios in B. spissa show a negative correlation to the concentrations in the surrounding pore waters. Lowest foraminiferal Fe/Ca ratios (87.0–101.0 μmol mol−1) were found at 465 m water depth, a location with a strong sharp Fe peak in the pore water next to the sediment surface and respectively, high Fe concentrations in the surrounding pore waters. Previous studies found no living specimens of B. spissa at this location. All these facts hint that the analysed specimens already were dead before the Fe flux started and the sampling site just recently turned anoxic due to fluctuations of the lower boundary of the OMZ near the sampling site (465 m water depth). Summarized Mn/Ca and Fe/Ca ratios are potential proxies for redox conditions, if cleaning protocols are carefully applied. The data presented here may be rated as base for the still pending detailed calibration.

Description: The aim of this study is to determine cloud-type resolved cloud radiative budgets and cloud radiative effects from surface measurements of broadband radiative fluxes over the Atlantic Ocean. Furthermore, based on simultaneous observations of the state of the cloudy atmosphere, a radiative closure study has been performed by means of the ECHAM5 single column model in order to identify the model's ability to realistically reproduce the effects of clouds on the climate system. An extensive database of radiative and atmospheric measurements has been established along five meridional cruises of the German research icebreaker Polarstern. Besides pyranometer and pyrgeometer for downward broadband solar and thermal radiative fluxes, a sky imager and a microwave radiometer have been utilized to determine cloud fraction and cloud type on the one hand and temperature and humidity profiles as well as liquid water path for warm non-precipitating clouds on the other hand. Averaged over all cruise tracks, we obtain a total net (solar + thermal) radiative flux of 144 W m(-2) that is dominated by the solar component. In general, the solar contribution is large for cirrus clouds and small for stratus clouds. No significant meridional dependencies were found for the surface radiation budgets and cloud effects. The strongest surface longwave cloud effects were shown in the presence of low level clouds. Clouds with a high optical density induce strong negative solar radiative effects under high solar altitudes. The mean surface net cloud radiative effect is -33 W m(-2). For the purpose of quickly estimating the mean surface longwave, shortwave and net cloud effects in moderate, subtropical and tropical climate regimes, a new parameterisation was created, considering the total cloud amount and the solar zenith angle. The ECHAM5 single column model provides a surface net cloud effect that is more cooling by 17 W m(-2) compared to the radiation observations. This overestimation in solar cooling is mostly caused by the shortwave impact of convective clouds. The latter show a large overestimation in solar cooling of up to 114 W m(-2). Mean cloud radiative effects of cirrus and stratus clouds were simulated close to the observations.

Description: Growing interest in the structure and dynamics of animal social networks has stimulated major advances [1], [2] and [3], but recording reliable association data for wild populations has remained challenging. While animal-borne ‘proximity’ tags have been available for some time [4], earlier devices were comparatively heavy, had limited detection ranges and/or necessitated recovery for data retrieval. We have developed wireless digital transceiver technology (‘Encounternet') that enables automated mapping of social networks in wild birds, yielding datasets of unprecedented size, quality and spatio-temporal resolution. Miniature, animal-borne tags record the proximity and duration of bird encounters, and periodically transfer logs to a grid of fixed receiver stations, from which datasets can be downloaded remotely for real-time analysis. We used our system to chart social associations in New Caledonian crows Corvus moneduloides [5] and [6]. Analysis of ca. 28,000 encounter logs for 34 crows over a 7-day period reveals a substantial degree of close-range association between non-family birds, demonstrating the potential for horizontal and oblique information exchange.

Description: Tropical coral reefs are among the most diverse marine ecosystems. In order to better understand temporal and spatial variation in late Quaternary biodiversity, foraminiferal faunas of two fossil, raised reef terraces at the southern Sinai Peninsula were studied and compared to modern coral reef faunas. Eleven U-series dates of shell fragments of the giant clam Tridacna sp. indicates deposition largely during marine isotope stage 5 (MIS 5), 77–129 kyr BP, for the two raised terraces. In these terraces, Amphistegina (A. lessonii and A. lobifera) dominates the five fossil foraminiferal associations. The fossil reef-flat association 1 has common Gypsina plana, Homotrema rubra and Acervulina spp., and fossil reef-flat association 2 consists of Amphistegina spp. Of the three fossil fore-reef associations, one has abundant porcelaneous taxa including Sorites, Amphisorus, Peneroplis and Borelis, one has a mix of porcelaneous taxa and attached-arborescent taxa (Homotrema and Placopsilina) and one has abundant attached and arborescent taxa (Miniacina, Gypsina, Acervulina and Planogypsina). The modern fringing reef is dominated by porcelaneous foraminifera, and three modern associations are identified. These include a lagoonal association with abundant Peneroplis pertusus, a reef-flat association dominated by Sorites orbiculus and a fore-reef association with porcelaneous taxa plus common H. rubra, Amphistegina lessonii and A. lobifera. Based on our data and including additional published information on regional biodiversity it appears that during MIS 5 foraminiferal biodiversity was higher and community structure was different than within the modern reefs. These data and regional paleo-climate patterns indicate that oceanographic conditions in the Red Sea were probably closer to normal marine conditions during the last interglacial than they are today.

Description: The internal consistency of measurements and computations of components of the CO2-system, namely total alkalinity (AT), total dissolved carbon dioxide (CT), CO2 fugacity (fCO2), and pH, has been confirmed repeatedly in open ocean studies when the CO2 system had been over determined. Differences between measured and computed properties, such as ΔfCO2 (=fCO2(measured) – fCO2(computed from AT and CT))/ fCO2(measured)× 100), there are usually below 5%. Recently, Hoppe et al. (2010) provided evidence of significantly larger ΔfCO2 in experimental setups. These observations are currently not well understood. Here we discuss a case from a series of phytoplankton culture experiments with ΔfCO2 of up to about 25%. ΔfCO2 varied systematically during the course of these experiments and showed a clear correlation with the accumulation of dissolved organic carbon (DOC). Culture and mesocosm experiments are often carried out under very high initial nutrient concentrations, yielding high biomass concentrations that in turn often lead to a substantial build-up of DOC. DOC can reach concentrations much higher than typically observed in the open ocean. To the extent that DOC includes organic acids and bases, it will contribute to the alkalinity of the seawater contained in the experimental device. Our analysis suggests that whenever substantial amounts of DOC are produced during the experiment, standard computer programs used to compute CO2 fugacity can underestimate true fCO2 significantly when the computation is based on AT and CT. Alternative explanations for large ΔfCO2, e.g. uncertainties of pKs, are explored as well, but are found to be of minor importance. Unless the effect of DOC-alkalinity is accounted for, this might lead to significant errors in the interpretation of the system under consideration to the experimentally applied CO2 perturbation, which could misguide the development of parameterisations used in simulations with global carbon cycle models in future CO2-scenarios.

Description: The Chile Triple Junction (CTJ) is the place where the Chile Ridge (Nazca–Antarctic spreading center) is subducting beneath the continental South American plate. Sediment accretion is active to the south of the CTJ in the area where the northward migrating Chile Ridge has collided with the continent since 14 Ma. At the CTJ, tectonic erosion of the overriding plate narrows and steepens the continental slope. We present here a detailed tomographic image of the upper lithospheric Antarctic–South America subduction zone where the Chile Ridge collided with the continent 3–6 Ma off Golfo de Penas. Results reveal that a large portion of trench sediment has been scraped off and frontally accreted to the forearc forming a 70–80 km wide accretionary prism. The velocity–depth model shows a discontinuity at 30–40 km landward of the deformation front, which is interpreted as the contact between the frontal (poorly consolidated sedimentary unit) and middle (more compacted sedimentary unit) accretionary prism. The formation of this discontinuity could be related to a short term episode of reduced trench sedimentation. In addition, we model the shape of the continental slope using a Newtonian fluid rheology to study the convergence rate at which the accretionary prism was formed. Results are consistent with an accretionary prism formed after the collision of the Chile Ridge under slow convergence rate similar to those observed at present between Antarctic and South America (∼2.0 cm/a). Based on the kinematics of the Chile Ridge subduction during the last 13 Ma, we propose that the accretionary prism off Golfo de Penas was formed recently (∼5 Ma) after the collision of the Chile Ridge with South America.

Description: In order to apply Sr/Ca and 44Ca/40Ca fractionation during calcium carbonate (CaCO3) formation as a proxy to reconstruct paleo-environments, it is essential to evaluate the impact of various environmental factors. In this study, a CO2 diffusion technique was used to crystallize inorganic calcite from aqueous solutions at different ionic strength/salinity by the addition of NaCl at 25 °C. Results show that the discrimination of Sr2+ versus Ca2+ during calcite formation is mainly controlled by precipitation rate (R in μmol/m2/h) and is weakly influenced by ionic strength/salinity. In analogy to Sr incorporation, 44Ca/40Ca fractionation during precipitation of calcite is weakly influenced by ionic strength/salinity too. At 25 °C the calcium isotope fractionation between calcite and aqueous calcium ions (Δ44/40Cacalcite-aq = δ44/40Cacalcite − δ44/40Caaq) correlates inversely to log R values for all experiments. In addition, an inverse relationship between Δ44/40Cacalcite-aq and log DSr, which is independent of temperature, precipitation rate, and aqueous (Sr/Ca)aq ratio, is not affected by ionic strength/salinity either. Considering the log DSr and Δ44/40Cacalcite-aq relationship, Sr/Ca and δ44/40Cacalcite values of precipitated calcite can be used as an excellent multi-proxy approach to reconstruct environmental conditions (e.g., temperature, precipitation rate) of calcite growth and diagenetic alteration.

Description: The GLOBEC Germany program (2002–2007) had the ambitious goal to resolve the processes impacting the recruitment dynamics of Baltic sprat (Sprattus sprattus L.) by examining various factors affecting early life history stages. At the start of the research program, a number of general recruitment hypotheses were formulated, i.e. focusing on (1) predation, (2) food availability, (3) physical parameters, (4) the impact of current systems, and finally (5) the importance of top-down vs bottom-up effects. The present study synthesizes the results of field sampling (2002 and 2003), laboratory experiments, and modeling studies to re-evaluate these hypotheses for the Baltic sprat stock. Recruitment success was quite different in the 2 years investigated. Despite a lower spawning stock biomass in 2003, the total number of recruits was almost 2-fold higher that year compared to 2002. The higher recruitment success in 2003 could be attributed to enhanced survival success during the post-larval/juvenile stage, a life phase that appears to be critical for recruitment dynamics. In the state of the Baltic ecosystem during the period of investigation, we consider bottom-up control (e.g. temperature, prey abundance) to be more important than top-down control (predation mortality). This ranking in importance does not vary seasonally. Prevailing water circulation patterns and the transport dynamics of larval cohorts have a strong influence on sprat recruitment success. Pronounced transport to coastal areas is detrimental for year-class strength particularly at high sprat stock sizes. A suggested mechanism is density-dependant regulation of survival via intra- and inter-specific competition for prey in coastal areas. A documented change in larval vertical migration behavior between the early 1990s and early 2000s increased the transport potential to the coast, strengthening the coupling between inter-annual differences in the magnitude and direction of wind-driven surface currents and year-to-year changes in reproductive success. However, due to the strong linkages and feed-back loops in the Baltic Sea food web, the most robust projections of the future strength of the Baltic sprat stock will need to take into account climate-driven changes in both abiotic (e.g., drift trajectories) and biotic (trophodynamic) factors. Although our understanding of processes affecting pre-recruit (larval) growth and survival has been advanced by the integrated research conducted within the GLOBEC Germany program, key mechanisms potentially affecting life stages outside of the spawning basins remain to be explored including the dynamics of coastal habitats of juveniles and the feeding and overwintering grounds of adults. Highlights: ► Food limitation may contribute to the formation of seasonal ‘windows of survival’. ► Change in larval migration exalted the importance of transport. ► Temperature is the most important physical factor influencing sprat recruitment. ► Bottom-up control is more important than top-down control. ► Projected Baltic water temperature increase suggests higher sprat recruitment potential.

Description: Emiliania huxleyi (strain B 92/11) was exposed to different nutrient supply, CO2 and temperature conditions in phosphorus controlled chemostats to investigate effects on organic carbon exudation and partitioning between the pools of particulate organic carbon (POC) and dissolved organic carbon (DOC). 14C incubation measurements for primary production (PP) and extracellular release (ER) were performed. Chemical analysis included the amount and composition of high molecular weight (〉1 kDa) dissolved combined carbohydrates (HMW-dCCHO), particulate combined carbohydrates (pCCHO) and the carbon content of transparent exopolymer particles (TEP-C). Applied CO2 and temperature conditions were 300, 550 and 900 μatm pCO2 at 14 °C, and additionally 900 μatm pCO2 at 18 °C simulating a greenhouse ocean scenario. Enhanced nutrient stress by reducing the dilution rate (D) from D = 0.3 d−1 to D = 0.1 d−1 (D = μ) induced the strongest response in E. huxleyi. At μ = 0.3 d−1, PP was significantly higher at elevated CO2 and temperature and DO14C production correlated to PO14C production in all treatments, resulting in similar percentages of extracellular release (PER; (DO14C production/PP) × 100) averaging 3.74 ± 0.94%. At μ = 0.1 d−1, PO14C production decreased significantly, while exudation of DO14C increased. Thus, indicating a stronger partitioning from the particulate to the dissolved pool. Maximum PER of 16.3 ± 2.3% were observed at μ = 0.1 d−1 at elevated CO2 and temperature. While cell densities remained constant within each treatment and throughout the experiment, concentrations of HMW-dCCHO, pCCHO and TEP were generally higher under enhanced nutrient stress. At μ = 0.3 d−1, pCCHO concentration increased significantly with elevated CO2 and temperature. At μ = 0.1 d−1, the contribution (mol % C) of HMW-dCCHO to DOC was lower at elevated CO2 and temperature while pCCHO and TEP concentrations were higher. This was most pronounced under greenhouse conditions. Our findings suggest a stronger transformation of primary produced DOC into POC by coagulation of exudates under nutrient limitation. Our results further imply that elevated CO2 and temperature will increase exudation by E. huxleyi and may affect organic carbon partitioning in the ocean due to an enhanced transfer of HMW-dCCHO to TEP by aggregation processes.

Description: Increasing concentrations of dissolved inorganic carbon (DIC) in the interior ocean is expected as a direct consequence of increasing concentrations of CO2 in the atmosphere. This extra DIC is often referred to as anthropogenic carbon (Cant), and its inventory, or increase rate, in the interior ocean has previously been estimated by a multitude of observational approaches. Each of these methods are associated with hard to test assumptions since Cant cannot be directly observed. Results from a simpler concept with few assumptions applied to the Atlantic Ocean are reported on here using two large data collections of carbon relevant bottle data. The change in column inventory on decadal time scales, i.e. the storage rate, of DIC, respiration compensated DIC and oxygen is calculated for the Atlantic Ocean. The average storage rates for DIC and oxygen is calculated to 0.72 ± 1.22 (95% confidence interval of the mean trend: 0.65–0.78) mol m−2 yr−1 and −0.54 ± 1.64 (95% confidence interval of the mean trend: –0.64–(−0.45)) mol m−2 yr−1, respectively, for the Atlantic Ocean, where the uncertainties reflect station-to-station variability and where the mean trends are non-zero at the 95% confidence level. The standard deviation mainly reflects uncertainty due to regional variations, whereas the confidence interval reflects the mean trend. The storage rates are similar to changes found by other studies, although with large uncertainty. For the subpolar North Atlantic the storage rates show significant temporal variation of all variables. This seems to be due to variations in the prevalence of subsurface water masses with different DIC concentrations leading to sometimes different signs of storage rates for DIC and Cant. This study suggest that accurate assessment of the uptake of CO2 by the oceans will require accounting not only for processes that influence Cant but also additional processes that modify CO2 storage.

Description: The stable silicon isotopic composition (δ30Si) of waters and diatoms has increasingly been used to investigate the biogeochemical cycling of Si in the major ocean basins. Here we present the first Si isotope data set from the northern South China Sea (NSCS), a large marginal sea system in the western North Pacific to examine sources and utilization of silicic acid (Si(OH)4). During two cruises in July–August 2009 (summer) and January 2010 (winter), samples for isotope measurements of dissolved Si(OH)4 (δ30SiSi(OH)4) and of biogenic silica (δ30SiBSi) in suspended particles were collected along a transect perpendicular to the coast from the inner shelf to the deep-water slope, as well as at the South East Asian Time-series Study (SEATS) station located in the NSCS basin. Surface δ30SiSi(OH)4 generally increased from values ∼+2.3‰ on the inner shelf to ∼+2.8‰ above the deep basin, suggesting an increasing utilization of dissolved Si(OH)4 reflecting the transition from eutrophic to oligotrophic conditions. The δ30SiBSi values were systematically lower than the corresponding δ30SiSi(OH)4 in the euphotic zone (above 100 m) on the shelf and slope. In contrast at station SEATS in the NSCS basin, δ30SiBSi signatures in both seasons were within error equal to δ30SiSi(OH)4 in the surface mixed layer (above 50 m) and δ30SiBSi in waters below were significantly higher than the corresponding δ30SiSi(OH)4. By comparing the field data with the Si isotope fractionation revealed by the Rayleigh or the steady state models, we demonstrate the existence of variable Si(OH)4 origins in different areas of the NSCS. Surface waters on the inner shelf were largely fed by nutrients from the Pearl River input. While the primary source of Si(OH)4 for the euphotic zone on the outer shelf and slope was upwelling or vertical mixing from underlying waters, the Si(OH)4 in the surface mixed layer of the NSCS basin might have originated from horizontal mixing with other highly fractionated surface waters. As a consequence, the Si isotope dynamics in the NSCS are largely controlled by variable biological fractionation of Si in waters from different sources with different initial Si isotopic compositions rather than any single source water.

Description: We conducted measurements of the five important short-lived organic bromine species in the marine boundary layer (MBL). Measurements were made in the Northern Hemisphere mid-latitudes (Sylt Island, North Sea) in June 2009 and in the tropical Western Pacific during the TransBrom ship campaign in October 2009. For the one-week time series on Sylt Island, mean mixing ratios of CHBr3, CH2Br2, CHBr2Cl and CH2BrCl were 2.0, 1.1, 0.2, 0.1 ppt, respectively. We found maxima of 5.8 and 1.6 ppt for the two main components CHBr3 and CH2Br2. Along the cruise track in the Western Pacific (between 41° N and 13° S) we measured mean mixing ratios of 0.9, 0.9, 0.2, 0.1 and 0.1 ppt for CHBr3, CH2Br2, CHBrCl2, CHBr2Cl and CH2BrCl. Air samples with coastal influence showed considerably higher mixing ratios than the samples with open ocean origin. Correlation analyses of the two data sets yielded strong linear relationships between the mixing ratios of four of the five species (except for CH2BrCl). Using a combined data set from the two campaigns and a comparison with the results from two former studies, rough estimates of the molar emission ratios between the correlated substances were: 9/1/0.35/0.35 for CHBr3/CH2Br2/CHBrCl2/CHBr2Cl. Additional measurements were made in the tropical tropopause layer (TTL) above Teresina (Brazil, 5° S) in June 2008, using balloon-borne cryogenic whole air sampling technique. Near the level of zero clear-sky net radiative heating (LZRH) at 14.8 km about 2.25 ppt organic bromine was bound to the five short-lived species, making up 13% of total organic bromine (17.82 ppt). CH2Br2 (1.45 ppt) and CHBr3 (0.56 ppt) accounted for 90% of the budget of short-lived compounds in that region. Near the tropopause (at 17.5 km) organic bromine from these substances was reduced to 1.35 ppt, with 1.07 and 0.12 ppt attributed to CH2Br2 and CHBr3, respectively.

Description: Radiogenic isotopes of hafnium (Hf) and neodymium (Nd) are powerful tracers for water mass transport and trace metal cycling in the present and past oceans. However, due to the scarcity of available data the processes governing their distribution are not well understood. Here we present the first combined dissolved Hf and Nd isotope and concentration data from surface waters of the Atlantic sector of the Southern Ocean. The samples were collected along the Zero Meridian, in the Weddell Sea and in the Drake Passage during RV Polarstern expeditions ANTXXIV/3 and ANTXXIII/3 in the frame of the International Polar Year (IPY) and the GEOTRACES program. The general distribution of Hf and Nd concentrations in the region is similar. However, at the northernmost station located 200 km southwest of Cape Town a pronounced increase of the Nd concentration is observed, whereas the Hf concentration is minimal, suggesting much less Hf than Nd is released by the weathering of the South African Archean cratonic rocks. From the southern part of the Subtropical Front (STF) to the Polar Front (PF) Hf and Nd show the lowest concentrations (〈0.12 pmol/kg and 10 pmol/kg, respectively), most probably due to the low terrigenous flux in this area and efficient scavenging of Hf and Nd by biogenic opal. In the vicinity of landmasses the dissolved Hf and Nd isotope compositions are clearly labeled by terrigenous inputs. Near South Africa Nd isotope values as low as εNd = −18.9 indicate unradiogenic inputs supplied via the Agulhas Current. Further south the isotopic data show significant increases to εHf = 6.1 and εNd = −4.0 documenting exchange of seawater Nd and Hf with the Antarctic Peninsula. In the open Southern Ocean the Nd isotope compositions are relatively homogeneous (εNd ∼ −8 to −8.5) towards the STF, within the Antarctic Circumpolar Current, in the Weddell Gyre, and the Drake Passage. The Hf isotope compositions in the entire study area only show a small range between εHf = + 6.1 and +2.8 support Hf to be more readily released from young mafic rocks compared to old continental ones. The Nd isotope composition ranges from εNd = −18.9 to −4.0 showing Nd isotopes to be a sensitive tracer for the provenance of weathering inputs into surface waters of the Southern Ocean.

Description: The transit time distribution method was applied to dichlorodifluoromethane and sulfur hexafluoride measurements from four cruises to the tropical North Atlantic between 2006 and 2009 in order to estimate anthropogenic carbon (C-ant) concentrations. By assuming an Inverse Gaussian distribution of the transit time distribution the best fit to the data was achieved with the ratio of mean age to width equals 1. Significant differences in the mean age and C-ant concentrations between the equatorial belt (5 degrees S-5 degrees N) and the Guinea dome area (5 degrees-15 degrees N) was found. Mean ages are higher and C-ant concentrations are lower in the Guinea dome area than at same depths, or densities, in the equatorial belt. The mean column inventories in the upper 1200 m are higher by about 3 mol m(-2) in the equatorial belt compared to the Guinea dome area. The mean column inventory of C-ant, for the whole water column, in the tropical Atlantic is 32.2 mol m(-2) (error range: 30.6-45.2 mol m(-2)), which is significantly lower than the previous estimates. The total C-ant inventory in the eastern tropical Atlantic is 2.5 Pg (error range: 2.3-3.5 Pg) for an area of 6 x 10(6) km(2), comprising the Guinea dome region and the equatorial belt. The equatorial belt has 40% higher storage of C-ant compared to the Guinea dome area which reflects the occurrence of relatively young deep waters at the equator, being high in anthropogenic carbon. Our tracer based C-ant estimates were compared to C-ant concentrations calculated with the TrOCA method applied to measurements conducted in 1999. The TrOCA based estimates are significantly higher than our tracer based C-ant estimates. Comparison between tracer measurements in 1999 and the 2006-2009 time-frame revealed possible speed-up of ventilation in the upper water column, increasing the C-ant concentration in this depth range at a faster rate and a C-ant increase of 12.1 mu mol kg(-1) in the tropical surface water was found

Description: Earth System Climate Models (ESCMs) are valuable tools that can be used to gain a better understanding of the climate system, global biogeochemical cycles and how anthropogenically-driven changes may affect them. Here we describe improvements made to the marine biogeochemical ecosystem component of the University of Victoria's ESCM (version 2.9). Major changes include corrections to the code and equations describing phytoplankton light limitation and zooplankton grazing, the implementation of a more realistic zooplankton growth and grazing model, and the implementation of an iron limitation scheme to constrain phytoplankton growth. The new model is evaluated after a 10 000-yr spin-up and compared to both the previous version and observations. For the majority of biogeochemical tracers and ecosystem processes the new model shows significant improvements when compared to the previous version and evaluated against observations. Many of the improvements are due to better simulation of seasonal changes in higher latitude ecosystems and the effect that this has on ocean biogeochemistry. This improved model is intended to provide a basic new ESCM model component, which can be used as is or expanded upon (i.e., the addition of new tracers), for climate change and biogeochemical cycling research.

Description: The distribution of dissolved, soluble and colloidal fractions of Al and Ti was assessed by ultrafiltration studies in the upper water column of the eastern tropical North Atlantic. The dissolved fractions of both metals were found to be dominated by the soluble phase smaller than 10 kDa. The colloidal associations were very low (0.2–3.4%) for Al and not detectable for Ti. These findings are in some contrast to previous estimations for Ti and to the predominant occurrence of both metals as hydrolyzed species in seawater. However, low tendencies to form inorganic colloids can be expected, as in seawater dissolved Al and dissolved Ti are present within their inorganic solubility levels. In addition, association with functional organic groups in the colloidal phase is unlikely for both metals. Vertical distributions of the dissolved fractions showed surface maxima with up to 43 nM of Al and 157 pM of Ti, reflecting their predominant supply from atmospheric sources to the open ocean. In the surface waters, excess dissolved Al over dissolved Ti was present compared to the crustal source, indicating higher solubility and thus elevated inputs of dissolved Al from atmospheric mineral particles. At most stations, subsurface minima of Al and Ti were observed and can be ascribed to scavenging processes and/or biological uptake. The dissolved Al concentrations decreased by 80–90% from the surface maximum to the subsurface minimum. Estimated residence times in the upper 100 m of the water column ranged between 1.6 and 4 years for dissolved Al and between 14 and 17 years for dissolved Ti. The short residence times are in some contrast to the low colloidal associations of Al and Ti and the assumed role of colloids as intermediates in scavenging processes. This suggests that either the removal of both metals occurs predominantly via direct transfer of the hydrolyzed species into the particulate fraction or that the colloidal phase is rapidly turned over in the upper water column.

Description: Global change is associated with fast and severe alterations of environmental conditions. Superimposed onto existing salinity variations in a semi-enclosed brackish water body such as the Baltic Sea, a decrease in salinity is predicted due to increased precipitation and freshwater inflow. Moreover, we predict that heavy precipitation events will accentuate salinity fluctuations near shore. Here, we investigated how the immune function of the broad-nosed pipefish (Syngnathus typhle), an ecologically important teleost with sex-role reversal, is influenced by experimentally altered salinities (control: 18 PSU, lowered: 6 PSU, increased: 30 PSU) upon infection with bacteria of the genus Vibrio. Salinity changes resulted in increased activity and proliferation of immune cells. However, upon Vibrio infection, individuals at low salinity were unable to mount specific immune response components, both in terms of monocyte and lymphocyte cell proliferation and immune gene expression compared to pipefish kept at ambient salinities. We interpret this as resource allocation trade-off, implying that resources needed for osmoregulation under salinity stress are lacking for subsequent activation of the immune defence upon infection. Our data suggest that composition of small coastal fish communities may change due to elevated environmental stress levels and the incorporated consequences thereof. Highlights: ► We investigated immune function in a coastal fish under a global change scenario. ► Effects of salinity variation on immune cells and immune gene expression were studied. ► Individuals in low salinity delayed the activation the specific immune response. ► Salinity change can result in more time for bacterial replication and a more virulent infection. ► Possibly, resources for osmoregulation under salinity stress are lacking for immune responses.

Description: Temporal and spatial patterns in eastern North Atlantic sea-surface temperatures (SST) were reconstructed for marine isotope stage (MIS) 11c using a submeridional transect of five sediment cores. The SST reconstructions are based on planktic foraminiferal abundances and alkenone indices, and are supported by benthic and planktic stable isotope measurements, as well as by ice-rafted debris content in polar and middle latitudes. Additionally, the larger-scale dynamics of the precipitation regime over northern Africa and the western Mediterranean region was evaluated from iron concentrations in marine sediments off NW Africa and planktic δ13C in combination with analysis of planktic foraminiferal abundances down to the species level in the Mediterranean Sea. Compared to the modern situation, it is revealed that during entire MIS 11c sensu stricto (ss), i.e., between 420 and 398 ka according to our age models, a cold SST anomaly in the Nordic seas co-existed with a warm SST anomaly in the middle latitudes and the subtropics, resulting in steeper meridional SST gradients than during the Holocene. Such a SST pattern correlates well with a prevalence of a negative mode of the modern North Atlantic Oscillation. We suggest that our scenario might partly explain the longer duration of wet conditions in the northern Africa during MIS 11c compared to the Holocene.

Description: Detecting changes in the formation dynamics of biofilms stemming from bacteria and unicellular microorganisms in their natural environment is of prime interest for biological, ecological as well as anti-fouling technology research. We developed a robust optical fiber-based biofilm sensor ready to be applied in natural aquatic environments for on-line, in situ and non-destructive monitoring of large-area biofilms. The device is based on the detection of the natural fluorescence of microorganisms constituting the biofilm. Basically, the intrinsic fluorescence of the amino acid tryptophan is excited at a wavelength of λ=280 nm and detected at λ=350 nm utilising a numerically optimized sensor head equipped with a UV-LED light source and optical fiber bundles for efficient fluorescence light collection. Calibration was carried out with tryptophan solutions and two characteristic marine bacteria strains revealing linear signal response, satisfactory background suppression, wide dynamic range, and an experimental detection limit of 4 × 10(3)cells/cm(2). Successful field experiments in the Baltic Sea accomplished over a period of twenty-one days provided for the first time continuous observation of biofilm formation dynamics in a natural habitat. Starting from the first adhering bacteria, the measurement yielded the characteristic three phases of biofilm formation up to a fully developed biofilm. The sensor system holds potential for applications in aquatic sciences including deep sea research and, after further miniaturisation, in the industrial and biomedical field.

Description: New radiometric and magnetostratigraphic data from Quillagua and Calama basins (Atacama desert) indicate that the stratigraphic record over the last 10 Ma includes two hiatuses, lasting approximately 2 and 4 million years respectively. These sedimentary gaps are thought to represent prolonged periods of hyperaridity in the region, with absence of sediment production and accumulation in the central depressions. Their remarkable synchrony with Antarctic and Patagonian glacial stages, Humboldt cold current enhancement and cold upwelling waters lead us to suggest long-term climate forcing. Higher frequency climate (orbital precession and eccentricity) forcing is thought to control the sequential arrangement of the lacustrine units deposited at times of lower aridity. Hyperaridity trends appear to be modulated by the activity of the South American Summer Monsoon, which drives precipitation along the high altitude areas to the east of Atacama. This precipitation increase combined with the eastward enlargement of the regional drainage during the late Pleistocene enabled water transfer from these high altitude areas to the low lying closed Quillagua basin and resulted in the deposition of the last widespread saline lacustrine deposits in this depression, before its drainage was open to the Pacific Ocean.

Description: The Baltic Ice Lake, Yoldia Sea, Ancylus Lake and Littorina Sea stages of regression and transgression controlled the history of the Baltic Sea since the last glacial period. Many details regarding their development remain unknown, including the question whether the regression of the Ancylus Lake (between 10,700 and 10,200 cal yr BP) took place west of the Darss Sill, or elsewhere. This study addresses whether a drowned river system in Fehmarn Belt (SW Baltic Sea) can be related to the drainage of the Ancylus Lake. The river channel is cut into glacial till in the western part of Fehmarn Belt. Here, the channel reaches an incision depth of up to 12 m at a base level of 40 m b.s.l. (below sea level). Near Mecklenburg Bay, the buried channel is incised down to 60 m b.s.l. and widens rapidly from several hundred meters to more than 1 km, fading towards east. It was mainly shaped as part of a glacial meltwater system at a maximum water level of 30 m b.s.l., and is therefore not related to the Ancylus Lake drainage. During the lowstand of the Baltic Ice Lake, local shallow water bodies covered the study area. A previously reported westward directed drainage of a lake in the eastern Fehmarn Belt could be restricted to a time interval between the highstand of the Ancylus Lake and prior to the Littorina Transgression. Timing, water level and potential water discharge of this event suggest a connection to a partial drainage of the Ancylus Lake. It is concluded that the threshold separating the Ancylus Lake from the North Sea needs to be located west of Fehmarn Belt. Highlights ► A paleo-river channel is incised into the seafloor of Fehmarn Belt, SW Baltic Sea. ► This channel is unrelated to the drainage of the Ancylus Lake through the Dana River. ► Widespread erosion took place after the Ancylus Lake phase of the Baltic Sea. ► This event relates to a partial drainage of the Ancylus Lake. ► A new threshold of the Ancylus Lake west of Fehmarn Belt is suggested.

Description: Dust is a relatively unconstrained flux in the geochemical cycle of Ca. The isotopic composition of dust-derived Ca has not been studied, though it is an important part of any attempt at deciphering Ca isotope-based proxy records. Accordingly, this study reports the elemental and calcium isotope geochemistry of 30 surface (upper ∼0.5 cm) sediments from an arid dust producer, the Black Rock Desert in northwestern Nevada. Geochemical data for sequential water and 0.5 N HCl leaches, meant to sample mobile Ca, and selected leached residues are presented, along with X-ray diffraction (XRD) determinations of major mineralogy. Bulk playa sediments have Ca concentrations between 0.28 and 40 wt.% (median: 6.8 wt.%) and calcite concentrations of 2–32%. Isotopically, Ca sampled by water leaches (〈1% of total Ca) are, on average, +0.33 ± 0.16‰ (1 SD) heavier than acid leaches (〉60% of total Ca), though the degree of fractionation (Δw-a) varies between 0‰ and 0.6‰. Acid leaches, which are the primary component of mobile Ca in the sediments, have δ44CaSRM-915a values of 0.78 ± 0.08‰, similar to the δ44Ca of modern nannofossil ooze and modern rivers. This means that dust produced in closed continental basins likely has little isotopic leverage to change the ocean’s isotopic composition, and suggests that the Ca isotopic composition of dust is tied to rivers/weathering. In addition, while the Ca concentration data in the water leach suggest that evaporative evolution controls the amount of Ca in this reservoir, the isotope data are inconsistent with this conclusion. Instead, we hypothesize that adsorption of Ca on clays controls the Ca isotope systematics in the water leach. This hypothesis requires that there is no significant isotopic fractionation during evaporite mineral precipitation and may suggest that sorption at rates appropriate for natural systems might fractionate differently than sorption at laboratory rates.

Description: Lake Ohrid shared by the Republics of Albania and Macedonia is formed by a tectonically active graben within the south Balkans and suggested to be the oldest lake in Europe. Several studies have shown that the lake provides a valuable record of climatic and environmental changes and a distal tephrostratigraphic record of volcanic eruptions from Italy. Fault structures identified in seismic data demonstrate that sediments have also the potential to record tectonic activity in the region. Here, we provide an example of linking seismic and sedimentological information with tectonic activity and historical documents. Historical documents indicate that a major earthquake destroyed the city of Lychnidus (today: city of Ohrid) in the early 6th century AD. Multichannel seismic profiles, parametric sediment echosounder profiles, and a 10.08m long sediment record from the western part of the lake indicate a 2m thick mass wasting deposit, which is tentatively correlated with this earthquake. The mass wasting deposit is chronologically well constrained, as it directly overlays the AD472/AD 512 tephra. Moreover, radiocarbon dates and cross correlation with other sediment sequences with similar geochemical characteristics of the Holocene indicate that the mass wasting event took place prior to the onset of the Medieval Warm Period, and is attributed it to one of the known earthquakes in the region in the early 6th century AD.

Description: A sensitive method using Competitive Ligand Exchange-Adsorptive Cathodic Stripping Voltammetry (CLE-ACSV) has been developed to determine for the first time iron (Fe) organic speciation in rainwater over the typical natural range of pH. We have adapted techniques previously developed in other natural waters to rainwater samples, using the competing ligand 1-nitroso-2-naphthol (NN). The blank was equal to 0.17 +/- 0.05 nM (n = 14) and the detection limit (DL) for labile Fe was 0.15 nM which is 10-70 times lower than that of previously published methods. The conditional stability constant for NN under rainwater conditions was calibrated over the pH range 5.52-6.20 through competition with ethylenediaminetetraacetic acid (EDTA). The calculated value of the logarithm of beta'(FE3+(NN)3) increased linearly with increasing pH according to log beta'(FE3+(NN)3) = 2.4 +/- 0.6 x pH + 11.9 +/- 3.5 (salinity =2.9, T= 20 degrees C). The validation of the method was carried out using desferrioxamine mesylate B (DFOB) as a natural model ligand for Fe. Adequate detection windows were defined to detect this class of ligands in rainwater with 40 mu M of NN from pH 5.52 to 6.20. The concentration of Fe-complexing natural ligands was determined for the first time in three unfiltered and one filtered rainwater samples. Organic Fe-complexing ligand concentrations varied from 104.2 +/- 4.1 nM equivalent of Fe(III) to 336.2 +/- 19.0 nM equivalent of Fe(III) and the logarithm of the conditional stability constants, with respect to Fe3+, varied from 21.1 +/- 0.2 to 22.8 +/- 0.3. This method will provide important data for improving our understanding of the role of wet deposition in the biogeochemical cycling of iron.

Description: Confocal Raman microscopy (CRM) mapping was used to investigate the microstructural arrangement and organic matrix distribution within the skeleton of the coral Porites lutea. Relative changes in the crystallographic orientation of crystals within the fibrous fan-system could be mapped, without the need to prepare thin sections, as required if this information is obtained by polarized light microscopy. Simultaneously, incremental growth lines can be visualized without the necessity of etching and hence alteration of sample surface. Using these methods two types of growth lines could be identified: one corresponds to the well-known incremental growth layers, whereas the second type of growth lines resemble denticle finger-like structures (most likely traces of former spines or skeletal surfaces). We hypothesize that these lines represent the outer skeletal surface before another growth cycle of elongation, infilling and thickening of skeletal areas continues. We show that CRM mapping with high spatial resolution can significantly improve our understanding of the micro-structural arrangement and growth patterns in coral skeletons.

Description: We have investigated the strontium isotope fractionation (Δ88/86Srcarb–aq) between inorganic calcite and aqueous Sr2+ ions by precipitation experiments at a constant temperature of 25 °C and precipitation rates (R) ranging from 102.3 to 104.2 μmol/m2/h. Strontium isotope ratios were measured using the 87Sr–84Sr double spike technique. It was found that strontium isotope fractionation in these calcites is strongly dependent on the precipitation rate: View the MathML source The measured δ88/86Sr values are significantly correlated with previously measured δ44/40Ca and Sr/Ca values of the same calcite samples: Δ88/86Srcarb–aq=+0.18∗Δ44/40Cacarb–aq-0.01 View the MathML source The slope of 88Sr/86Sr versus 44Ca/40Ca fractionation is 0.18 ± 0.04 and compatible with a kinetic fractionation during dehydration of the strontium and calcium ions, but not with isotope fractionation in a diffusive boundary layer. Using published equilibrium Δ44/40Cacarb–aq and View the MathML source values we estimate the equilibrium isotope fractionation of strontium to be very close to zero (Δ88/86Sreq(carb–aq) = −0.01 ± 0.06‰). This estimate is confirmed by strontium isotope values of natural inorganic calcites that precipitated very slowly in basalts of the ocean crust. The results from the inorganic calcites are used to explain strontium isotope fractionation of planktic foraminifera. Specimens of two warm water species (Globigerinoides ruber and Globigerinoides sacculifer) were picked from the Holocene section of a Caribbean sediment core. We found no significant difference in δ88/86Sr between the two species. In addition, G. ruber specimens from Marine Isotope Stage 2 in the same core show δ88/86Sr values identical to the Holocene specimens. The strontium isotopes of both foraminifera species are strongly fractionated (Δ88/86Srcarb–aq = −0.248 ± 0.005‰) when compared to published data of other major marine calcifiers. Applying the results from the inorganic precipitation experiments we find that the strong foraminiferal strontium isotope fractionation can be explained by calcification in a largely open system at high precipitation rates, comparable in magnitude to rates known from scleractinian reef corals. This interpretation is in good agreement with the kinetic calcification model for planktic foraminifera by Kisakürek et al. (2011), which was based on calcium isotopes and elemental Sr/Ca ratios.

Description: The European Community Marine Strategy Framework Directive (MSFD) was established to provide guidelines for monitoring the quality of marine ecosystems. Monitoring the status of marine environments is traditionally based on macrofauna surveys, for which standardised methods have been established. Benthic foraminifera are also good indicators of environmental status because of their fast turnover rates, high degree of specialisation, and the preservation of dead assemblages in the fossil record. In spite of the growing interest in foraminiferal bio-monitoring during the last decades, no standardised methodology has been proposed until today. The aim of the FOraminiferal BIo-MOnitoring (FOBIMO) expert workshop, held in June 2011 at Fribourg, Switzerland, which assembled 37 scientists from 24 research groups and 13 countries, was to develop a suite of standard methods. This paper presents the main outcome of the workshop, a list of motivated recommendations with respect to sampling devices, sample storage, treatment, faunal analysis and documentation. Our recommendations fulfil the criteria imposed both by scientific rigour and by the practical limitations of routine studies. Hence, our aim is to standardise methodologies used in bio-monitoring only and not to limit the use of different methods in pure scientific studies. Unless otherwise stated, all recommendations concern living (stained) benthic foraminiferal assemblages. We have chosen to propose two types of recommendations. Mandatory recommendations have to be followed if a study wants to qualify as sound and compatible to the norms. The most important of these recommendations are the interval from 0 to 1 cm below the sediment surface has to be sampled, and an interface corer or box corer that keeps the sediment surface intact is to be used for offshore surveys. A grab sampler must not be deployed in soft sediments. Three replicate samples are to be taken and analysed separately. Samples are to be washed on a 63-mu m screen, and the living benthic foraminiferal fauna of the 〉 125 mu m fraction is to be analysed. Splits are to be picked and counted entirely, and all counted foraminifera from at least one replicate per station have to be stored in micropalaeontological slides. Census data, supplementary laboratory data and microslides have to be archived. Advisory recommendations are to sample in autumn, to have a sample size of 50 cm(2) or a tube of 8 cm inner diameter, to use 〉 70% ethanol as a preservative, rose Bengal at a concentration of 2 grams per litre for staining, and a staining time of at least 14 days. The split size should be defined by a target value of 300 specimens, heavy liquid separation should be avoided, and the 63-125 mu m fraction or deeper sediment levels may be considered in some environments. We are convinced that the application of this protocol by a large number of scientists is a necessary first step to a general acceptance of benthic foraminifera as a reliable tool in bio-monitoring studies

Description: The variability of the north-polar stratospheric vortex is a prominent aspect of the middle atmosphere. This work investigates a wide class of statistical models with respect to their ability to model geopotential and temperature anomalies, representing variability in the polar stratosphere. Four partly nonstationary, nonlinear models are assessed: linear discriminant analysis (LDA); a cluster method based on finite elements (FEM-VARX); a neural network, namely the multi-layer perceptron (MLP); and support vector regression (SVR). These methods model time series by incorporating all significant external factors simultaneously, including ENSO, QBO, the solar cycle, volcanoes, to then quantify their statistical importance. We show that variability in reanalysis data from 1980 to 2005 is successfully modeled. The period from 2005 to 2011 can be hindcasted to a certain extent, where MLP performs significantly better than the remaining models. However, variability remains that cannot be statistically hindcasted within the current framework, such as the unexpected major warming in January 2009. Finally, the statistical model with the best generalization performance is used to predict a winter 2011/12 with warm and weak vortex conditions. A vortex breakdown is predicted for late January, early February 2012.