ALBERT

Description: Mud diapirism has recently been recognized in several modern accretionary wedges. It provides an important means of dewatering accretionary wedges and should be regarded as an important process for producing the melanges found in both modern and ancient accretionary terranes. Mud diapirism affects a large area of the Barbados Ridge Accretionary Complex. The distribution of the mud diapirs appears to be primarily controlled by the presence of underconsolidated terrigenous submarine fan deposits that are being accreted to the complex. The frequency of diapir occurrence decreases northward as the fan becomes thinner. Mud diapirs are absent from the very eastern most part of the complex formed from sediments accreted at its toe, with the exception of a few mud volcanoes on the ocean floor in front of the complex. The initiation of diapirism appears to be spatially coincident with the onset of subcretion, or underplating, of sediment to the base of the complex at a ramp between two levels of decollement. It is proposed that the release of mud and pore water from the subcreted sediments is a direct or indirect cause of most of the mud diapirism in the accretionary complex. There is a range of diapiric form dependent on the viscosity of the mud, from mud volcanoes fed by low viscosity mud, to higher viscosity mud ridges. The diapirs in the eastern areas of the complex are generally mud volcanoes with narrow conduits feeding a surface mound. Mud ridges are prominent in the western parts of the complex. This is interpreted as reflecting a general westward decrease in the fluid content of the accretionary complex. Bottom-simulating seismic reflectors formed by gas hydrate are commonly developed in the areas of mud volcano occurrences. The presence of the hydrate indicates that large volumes of methane are being generated at depth in these regions. The generation of methane may be contributing to zones of overpressuring in the wedge. Methane may also be partly responsible for driving the diapiric material to the surface to form mud volcanoes. Ridges in the subducting oceanic crust beneath the accretionary complex locally enhance diapirism above their crests and southern flanks. Faults formed later in the development of the complex are more commonly associated with diapirism than those resulting from accretion at the toe of the wedge. These later faults play an important role in controlling the sites of individual mud volcanoes, chains of mud volcanoes, and mud ridges.

Description: Structure I methane hydrates are formed in situ from water-in-mineral oil emulsions in a high pressure rheometer cell. Viscosity is measured as hydrates form, grow, change under flow, and dissociate. Experiments are performed at varying water volume fraction in the original emulsion (0–0.40), temperature (0–6 °C), and initial pressure of methane (750–1500 psig). Hydrate slurries exhibit a sharp increase in viscosity upon hydrate formation, followed by complex behavior dictated by factors including continued hydrate formation, shear alignment, methane depletion/dissolution, aggregate formation, and capillary bridging. Hydrate slurries possess a yield stress and are shear-thinning fluids, which are described by the Cross model. Hydrate slurry viscosity and yield stress increased with increasing water volume fraction. As driving force for hydrate formation decreases (increasing temperature, decreasing pressure), hydrate slurry viscosity increases, suggesting that slower hydrate formation leads to larger and more porous aggregates. In total, addition of water to a methane saturated oil can cause more than a fifty-fold increase in viscosity if hydrates form.

Description: The relationship between the biomass of reproductively mature individuals (spawning stock) and the resulting offspring added to the population (recruitment), the stock–recruitment relationship, is a fundamental and challenging problem in all of population biology. The steepness of this relationship is commonly defined as the fraction of recruitment from an unfished population obtained when the spawning stock biomass is 20% of its unfished level. Since its introduction about 20 years ago, steepness has become widely used in fishery management, where it is usually treated as a statistical quantity. Here, we investigate the reproductive ecology of steepness, using both unstructured and age‐structured models. We show that if one has sufficient information to construct a density‐independent population model (maximum per capita productivity and natural mortality for the unstructured case or maximum per capita productivity, natural mortality and schedules of size and maturity at age for the structured model) then one can construct a point estimate for steepness. Thus, steepness cannot be chosen arbitrarily. If one assumes that the survival of recruited individuals fluctuates within populations, it is possible, by considering the early life history, to construct a prior distribution for steepness from this same demographic information. We develop the ideas for both compensatory (Beverton–Holt) and over‐compensatory (Ricker) stock–recruitment relationships. We illustrate our ideas with an example concerning bluefin tuna (Thunnus thynnus/orientalis, Scombridae). We show that assuming that steepness is unity when recruitment is considered to be environmentally driven is not biologically consistent, is inconsistent with a precautionary approach, and leads to the wrong scientific inference (which also applies for assigning steepness any other single value).

Description: The total length, the dorsal mantle length and the weight of the lens of Octopus vulgaris Lamarck have been related to the live body weight. The effect of fixation on the body weight and dorsal mantle length has been tested on six small octopuses.

Description: Two discontinuous tephra layers were discovered at Burney Spring Mountain, northern California. Stratigraphic relationships suggest that they are two distinct primary fall tephras. The geochemistries of these tephras from electron probe microanalysis were compared with those of known layers found in the area to test for potential correlations, using clustering analysis on geochemistry. In most cases, geochemical data from a tephra layer can be assigned to a single cluster, but in some cases the analyses are spread over several clusters. This spreading is a direct result of mixing and reworking of several tephra layers. The mixing, in turn, appears to be related to the influence of wind in a marshy environment.

Description: Four primary glass populations, well defined by their Sr, Ba and Y concentrations, occur in the Youngest Toba Tuff (YTT), which was deposited during a Supereruption of the Toba caldera complex in northern Sumatra 75 ka. Average concentrations of major and trace elements indicate a coherent, systematic Variation of glass composition across populations. No clear pattern in the areal distribution of these four glass groups can be discerned. The multiple glass populations of the YTT easily distinguish it from the single homogeneous glass population of the Middle Toba Tuff (~500 ka), as represented by its basal vitrophyre, and that of the Oldest Toba Tuff (~800 ka), as represented by ash Layer D at the Ocean Drilling Program site 758 in the Indian Ocean.

Description: The relationship between the biomass of reproductively mature individuals (spawning stock) and the resulting offspring added to the population (recruitment), the stock–recruitment relationship, is a fundamental and challenging problem in all of population biology. The steepness of this relationship is commonly defined as the fraction of recruitment from an unfished population obtained when the spawning stock biomass is 20% of its unfished level. Since its introduction about 20 years ago, steepness has become widely used in fishery management, where it is usually treated as a statistical quantity. Here, we investigate the reproductive ecology of steepness, using both unstructured and age‐structured models. We show that if one has sufficient information to construct a density‐independent population model (maximum per capita productivity and natural mortality for the unstructured case or maximum per capita productivity, natural mortality and schedules of size and maturity at age for the structured model) then one can construct a point estimate for steepness. Thus, steepness cannot be chosen arbitrarily. If one assumes that the survival of recruited individuals fluctuates within populations, it is possible, by considering the early life history, to construct a prior distribution for steepness from this same demographic information. We develop the ideas for both compensatory (Beverton–Holt) and over‐compensatory (Ricker) stock–recruitment relationships. We illustrate our ideas with an example concerning bluefin tuna (Thunnus thynnus/orientalis, Scombridae). We show that assuming that steepness is unity when recruitment is considered to be environmentally driven is not biologically consistent, is inconsistent with a precautionary approach, and leads to the wrong scientific inference (which also applies for assigning steepness any other single value).

Description: Stock‐based and ecosystem‐based indicators are used to provide a new diagnosis of the fishing impact and environmental status of European seas. In the seven European marine ecosystems covering the Baltic and the North‐east Atlantic, (i) trends in landings since 1950 were examined; (ii) syntheses of the status and trends in fish stocks were consolidated at the ecosystem level; and (iii) trends in ecosystem indicators based on landings and surveys were analysed. We show that yields began to decrease everywhere (except in the Baltic) from the mid‐1970s, as a result of the over‐exploitation of some major stocks. Fishermen adapted by increasing fishing effort and exploiting a wider part of the ecosystems. This was insufficient to compensate for the decrease in abundance of many stocks, and total landings have halved over the last 30 years. The highest fishing impact took place in the late 1990s, with a clear decrease in stock‐based and ecosystem indicators. In particular, trophic‐based indicators exhibited a continuous decreasing trend in almost all ecosystems. Over the past decade, a decrease in fishing pressure has been observed, the mean fishing mortality rate of assessed stocks being almost halved in all the considered ecosystems, but no clear recovery in the biomass and ecosystem indicators is yet apparent. In addition, the mean recruitment index was shown to decrease by around 50% in all ecosystems (except the Baltic). We conclude that building this kind of diagnosis is a key step on the path to implementing an ecosystem approach to fisheries management.

Description: Teleost fish grow continuously throughout their lifespan, and this growth includes visual system components: eyes, optic nerves, and brain. As fish grow, the optic nerve lengthens and neural signals must travel increasing distances from the eye to the optic tectum along thousands of retinal ganglion cell (RGC) axons. Larger fish have better vision that enhances their ability to capture prey, but they are faced with the potential computational problem of changes in the relative timing of visual information arriving at the brain. Optic nerve conduction delays depend on RGC axon conduction velocities, and velocity is primarily determined by axon diameters. If axon diameters do not increase in proportion to body length, then absolute and relative conduction delays will vary with fish size. We have measured optic nerve lengths and axon diameter distributions in different sized zebrafish (Danio rerio) and goldfish (Carassius auratus) and find that, as both species of fish grow, axon diameters increase to reduce average conduction delays by about half and to keep relative delays constant. This invariance of relative conduction delays simplifies computational problems faced by the optic tectum.

Description: As sessile filter feeders, sponges rely on a highly efficient fluid transport system. Their physiology depends on efficient water exchange, which is performed by the aquiferous system. This prominent poriferan anatomical character represents a dense network of incurrent and excurrent canals on which we lack detailed 3D models. To overcome this, we investigated the complex leucon‐type architecture in the demosponge Tethya wilhelma using corrosion casting, microtomography, and 3D reconstructions. Our integrative qualitative and quantitative approach allowed us to create, for the first time, high‐resolution 3D representations of entire canal systems which were used for detailed geometric and morphometric measurements. Canal diameters lack distinct size classes, and bifurcations are non‐uniformly ramified. A relatively high number of bifurcations show previously unknown and atypical cross‐sectional area ratios. Scaling properties and topological patterns of the canals indicate a more complex overall architecture than previously assumed. As a consequence, it might be more convenient to group canals into functional units rather than hierarchical clusters. Our data qualify the leucon canal system architecture of T. wilhelma as a highly efficient fluid transport system adapted toward minimal flow resistance. Our results and approach are relevant for a better understanding of sponge biology and cultivation techniques.

Description: The tephrostratigraphy of lake sediments in the Endinger Bruch provides the first robust age model for the Lateglacial palynological records of Vorpommern (north-east Germany). Cryptotephra investigations revealed six tephra layers within sediments spanning from Open vegetation phase I (∼Bølling, ∼15 ka) to the Early Holocene Betula/Pinus forest phase (∼Pre-boreal, ∼10.5 ka). Four of these layers have been correlated with previously described tephra layers found in sites across Europe. The Laacher See Tephra (Eifel Volcanic Field) is present in very high concentrations within sediments of the Lateglacial Betula (/Pinus) forest phase (∼Allerød). The Vedde Ash (Iceland) lies midway through Open vegetation phase III (∼Younger Dryas). The Hässeldalen and the Askja tephras (Iceland) lie in the Early Holocene Betula/Pinus forest phase (∼Preboreal). These tephra layers have independently derived age estimates, which have been imported into the Endinger Bruch record. Furthermore, the layers facilitate direct correlation of the regional vegetation record with other palaeoenvironmental archives, which contain one or more of the same tephra layers, from Greenland to Southern Europe. In doing this, localized variations are confirmed in some aspects of the pollen stratigraphy; however, transitions between the main vegetation phases appear to occur synchronously (within centennial errors) with the equivalent environmental transitions observed in sites across the European continent.

Description: Here we present a tephrostratigraphic record (core Co1202) recovered from the northeastern part of Lake Ohrid (Republics of Macedonia and Albania) reaching back to Marine Isotope Stage (MIS) 6. Overall ten horizons (OT0702-1 to OT0702-10) containing volcanic tephra have been recognised throughout the 14.94m long sediment succession. Four tephra layers were visible at macroscopic inspection (OT0702-4, OT0702-6, OT0702-8 and OT0702-9), while the remaining six are cryptotephras (OT0702-1, OT0702-2, OT0702-3, OT0702-5, OT0702-7 and OT0702-10) identified from peaks in K, Zr and Sr intensities, magnetic susceptibility measurements, and washing and sieving of the sediments. Glass shards of tephra layers and cryptotephras were analysed with respect to their major element composition, and correlated to explosive eruptions of Italian volcanoes. The stratigraphy and the major element composition of tephra layers and cryptotephras allowed the correlation of OT0702-1 to AD 472 or AD 512 eruptions of Somma-Vesuvius, OT0702-2 to the FL eruption of Mount Etna, OT0702-3 to the Mercato from Somma-Vesuvius, OT0702-4 to SMP1-e/Y-3 eruption from the Campi Flegrei caldera, OT0702-5 to the Codola eruption (Somma-Vesuvius or Campi Flegrei), OT0702-6 to the Campanian Ignimbrite/Y-5 from the Campi Flegrei caldera, OT0702-7 to the Green Tuff/Y-6 eruption from Pantelleria Island, OT0702-8 to the X-5 eruption probably originating from the Campi Flegrei caldera, OT0702-9 to the X-6 eruption of generic Campanian origin, and OT0702-10 to the P-11 eruption from Pantelleria Island. The fairly well-known ages of these tephra layers and parent eruptions provide new data on the dispersal and deposition of these tephras and, furthermore, allow the establishment of a chronological framework for core Co1202 for a first interpretation of major sedimentological changes.

Description: Innate immunity is the front line of self-defense against microbial infection. After searching for natural substances that regulate innate immunity using an ex vivo Drosophila culture system, we identified a novel dimeric chromanone, gonytolide A, as an innate immune promoter from the fungus Gonytrichum sp. along with gonytolides B and C. Gonytolide A also increased TNF-α-stimulated production of IL-8 in human umbilical vein endothelial cells.

Description: Hundreds of Sepia officinalis were hatched and cultured through the life cycle in each of 13 populations. Two genetic lines were maintained: one for an unprecedented seven generations and another presently in its fourth. All generations—save one—produced animals in excess of 1·0 kg body weight. Seven of eight generations with adequate data records had mean weights of 1–2 kg, and the largest cuttlefish reared were a male 2·6 kg and a female 2·9 kg. Fecundity levels were high, but there was a trend towards decreased fertility in later generations, with fertilization rates dropping below 10%. In the 7th generation, most mature animals failed to engage in agonistic courtship and mating behaviour. Almost no normal eggs were laid and none was fertile, thus ending the lineage. Most culture took place at 20–24°C and temperature generally explained variations in life span duration: being of shorter length at higher temperatures. Life spans were consistently longer at 20°C and sizes were greater than predicted from previously published literature. In both lines there was a trend towards larger individuals and longer life spans in subsequent generations. Survival of hatchlings typically exceeded 90% for two months post-hatching, and survival averaged 50% or higher to sexual maturity when corrected for animals removed from the populations for experimental use.

Description: Conceptual models predict a unimodal effect of consumer abundance on prey diversity with the highest diversity at intermediate consumer abundance (intermediate disturbance hypothesis). Consumer selectivity and prey productivity are assumed to be further important determinants. Preferential grazing on dominant prey species favoured by high nutrient supply is supposed to increase prey diversity, whereas the effect of consumers on prey diversity may be negative under low nutrient conditions (grazer reversal hypothesis). We tested the effect of four common consumers the isopod Idotea baltica, the amphipod Gammarus oceanicus, and the gastropods Littorina littorea and Rissoa membranacea on diversity and composition of epiphytes growing on eelgrass Zostera marina. Consumer density was manipulated (four levels: grazer free control, low, medium, high) based on abundances observed in eelgrass systems. Additionally, we manipulated nutrient supply (three levels) and the presence of Idotea in a factorial experiment. The impact of consumer abundance on epiphyte diversity varied depending on consumer identity and epiphyte evenness was affected rather than species number in this short-term experiment. Idotea reduced epiphyte diversity (Shannon-Wiener index H') and Gammarus increased epiphyte diversity. Littorina had no effect at low and medium abundance, but a negative effect in the high density treatment. Only Rissoa supported the conceptual models as it caused the proposed unimodal pattern in epiphyte diversity. The varying species-specific selectivity of the studied consumers is likely to explain their diverse impact on epiphyte diversity. Nutrients enhanced epiphyte diversity at medium enrichment, whereas higher nutrient supply reduced epiphyte diversity. The effect of Idotea changed from negative at low nutrient concentration to positive at higher nutrient supply, supporting the grazer reversal hypothesis. This study implies that consumer species identity and nutrient concentrations are important in controlling prey diversity and composition. Different consumer selectivity and changes in selectivity with growing consumer abundance and nutrient concentration are the causal factors for this effect.

Description: Climate change will increase both average temperatures and extreme summer temperatures. Analyses of the fitness consequences of climate change have generally omitted negative fitness and population declines associated with heat stress. Here, we examine how seasonal and interannual temperature variability will impact fitness shifts of ectotherms from the past (1961–1990) to future (2071–2100), by modelling thermal performance curves (TPCs) for insect species across latitudes. In temperate regions, climate change increased the length of the growing season (increasing fitness) and increased the frequency of heat stress (decreasing fitness). Consequently, species at mid-latitudes (20–40°) showed pronounced but heterogeneous responses to climate change. Fitness decreases for these species were accompanied by greater interannual variation in fitness. An alternative TPC model and a larger data set gave qualitatively similar results. How close maximum summer temperatures are to the critical thermal maximum of a species – the thermal buffer – is a good predictor of the change in mean fitness expected under climate change. Thermal buffers will decrease to near or below zero by 2100 for many tropical and mid-latitude species. Our forecasts suggest that mid-latitude species will be particularly susceptible to heat stress associated with climate change due to temperature variation

Description: Abstract Aims Bacterially induced calcium carbonate precipitation from various isolates was investigated aiming at developing an environmentally friendly technique for ornamental stone protection and restoration. Methods and Results Microorganisms isolated from stone samples and identified using 16S rDNA and biochemical tests promoted calcium carbonate precipitation in solid and novel liquid growth media. Biomineral morphology was studied on marble samples with scanning electron microscopy. Most isolates demonstrated specimen weight increase, covering partially or even completely the marble surfaces mainly with vaterite. The conditions under which vaterite precipitated and its stability throughout the experimental runs are presented. Conclusions A growth medium that facilitated bacterial growth of different species and promoted biomineralization was formulated. Most isolates induced biomineralization of CaCO3. Microorganisms may actually be a milestone in the investigation of vaterite formation facilitating our understanding of geomicrobiological interactions. Pseudomonas, Pantoea and Cupriavidus strains could be candidates for bio‐consolidation of ornamental stone protection. Significance and Impact of the Study Characterization of biomineralization capacity of different bacterial species improves understanding of the bacterially induced mineralization processes and enriches the list of candidates for bio‐restoration applications. Knowledge of biomineral morphology assists in differentiating mineral from biologically induced precipitates.

Description: The round goby Neogobius melanostomus is one of the most wide-ranging invasive fish on earth, with substantial introduced populations within the Laurentian Great Lakes watershed, the Baltic Sea and several major European rivers. Rapid expansion and deleterious ecosystem effects have motivated extensive research on this species; here this research is synthesized. Maps of the global distribution are provided and the invasion history of N. melanostomus, which spread more rapidly at first in North America, but has undergone substantial expansion over the past decade in the Baltic Sea, is summarized. Meta-analyses comparing their size at age, diet, competitors and predators in North American and European ecosystems are provided. Size at age is region specific, with saline habitats typically supporting larger and faster growing individuals than fresh water. Neogobius melanostomus prey differs substantially between regions, demonstrating a capacity to adapt to locally abundant food sources. Neogobius melanostomus comprise at least 50% of the diet of eight taxa in at least one site or life stage; in total, 16 predator taxa are documented from the Laurentian Great Lakes v. five from Eurasia. Invasive N. melanostomus are the only common forage fish to heavily exploit mussels in the Laurentian Great Lakes and the Baltic Sea, facilitating the transfer of energy from mussels to higher trophic levels in both systems. Neogobius melanostomus morphology, life history, reproduction, habitat preferences, environmental tolerances, parasites, environmental effects, sampling strategies and management are also discussed. Neogobius melanostomus inhabit a wide range of temperate freshwater and brackish-water ecosystems and will probably continue to spread via ballast water, accidental bait release and natural dispersal worldwide. Climate change will probably enhance N. melanostomus expansion by elevating water temperatures closer to its energetic optimum of 26° C. Future research needs are presented; most pressing are evaluating the economic effects of N. melanostomus invasion, determining long-term population level effects of egg predation on game-fish recruitment and comparing several variables (density, ecological effects morphology and life history) among invaded ecosystems. This review provides a central reference as researchers continue studying N. melanostomus, often as examples for advancing basic ecology and invasion biology.

Description: Fluvial processes dominate sediment flux from most cold environments and as such are particularly sensitive to environmental change. However, these systems demonstrate high variability in flow and sediment transfer rates in both the short and long-term which presents specific problems for establishing integrated sediment flux studies. The objective of this paper is to briefly review the nature of fluvial and floodplain sediment sources in cold environments and to make recommendations on the measurement of fluvial sediment fluxes from these sources to sinks. The paper outlines a framework for examining fluvial sediment fluxes in cold environments including: sources of sediment in glacial and periglacial environments; techniques for measuring fluvial sediment transfers; and methods for measuring contemporary deposition in lacustrine sediment sinks. Within this framework, we stress that it is particularly important to provide consistency in methods for monitoring sediment flux and to adopt appropriate sampling frequencies. We recommend that the most appropriate methods for establishing integrated sediment flux studies in these cold environments are: repeat surveys and terrestrial laser scanning of valley and slope sediment stores on a monthly – daily frequency; weekly-daily sediment budgeting of bedload transfer using rapid resurvey methods; hourly or better time series of suspended and solute transport using data logger acquisition systems; and monitoring of lacustrine sedimentation using sediment accumulation sensors and/or weekly-daily estimates from passive sediment traps. Application of the proposed integrated framework will improve our understanding of sediment flux in cold environments and allow us to better assess the sensitivity of cold environments to environmental change within the context of contemporary and past sediment flux.

Description: Mussel aquaculture is a growing industry in Scotland, dominated by the production of Mytilus edulis. However, Mytilus trossulus, Mytilus galloprovincialis, and their hybrids with M. edulis have recently been detected in Scotland. At some farms, M. trossulus have been associated with significant losses in production because of presenting low meat yields and fragile shells. In the present study, M. edulis, M. trossulus, and their hybrids were examined from three cultivation areas in order to investigate shell and meat characteristics and advise on future management of mixed-species areas in Scotland. Results suggest that M. edulis is likely to consistently outperform M. trossulus and hybrids in mixed-species areas, but that M. trossulus meat yields from different areas can vary considerably. The ability to classify mussels into two (M. edulis and non-edulis) groups suggests that separation of M. trossulus genotypes could potentially be achieved by grading the harvested mussels. In the most affected areas, however, the fallowing of cultivation sites and importation of unispecific M. edulis spat appear as an alternative. Management of this problem in Scotland is likely to involve the implementation of area-specific measures, and the establishment of clear guidance on good practice aiming at preventing further distribution of M. trossulus.

Description: In both terrestrial and aquatic environments introductions of non-indigenous species are continuing and represent one important component of global change. Negative biotic interactions by resident species may prevent successful invaders from becoming pests. Few experimental data are available on the presence and significance of such biotic resistance other than predation or competition. This study addresses the role of habitat structure provided by a native eelgrass (Zostera marina) canopy on growth and survival of the non-indigenous mussel Musculista senhousia, a habitat-modifying gregarious suspension feeder with strong effects on native infauna and eelgrass. In 2 southern California bays, a series of transplantation experiments using tagged mussels revealed that inside an eelgrass canopy, Musculista growth rates were reduced by more than half in 3 of 4 experiments compared to adjacent unvegetated areas. Musculista survival also decreased inside the vegetation in a 4-mo experiment. As one element of habitat structure, we tested the effects of eelgrass patch size, using natural (1 site) and planted (1 site) eelgrass patches of defined sizes. Growth rates of Musculista were highest outside the vegetation and decreased as eelgrass patch size increased. As a potential mechanism for the canopy effects, we suggest that Musculista receives less food inside the vegetation. In the experimental plots, the presence and spatial extent of the macrophyte canopy strongly affected near bottom (10 cm) horizontal water flow assessed with a direct dye tracking method. Reduced mussel growth rates were linearly associated with lower water flow, and presumably, food flux. Over a period of 7 mo, food resources (particulate chlorophyll a) were consistently lower 1 and 5 cm above the sea floor inside eelgrass patches compared to the sand flat. The reduction in food availability matched the growth reduction of Musculista. Also, mussel condition (dry flesh mass/shell mass) was worse in individuals growing in eelgrass than in the sand flat. Previous experiments revealed that dense beds of Musculista impede the rhizome growth and vegetative propagation of eelgrass, yet mussels attain abundances sufficient for interference only if eelgrass beds are patchy. Thus, anthropogenic disturbances on eelgrass beds, which often result in meadow fragmentation, and the proliferation of Musculista may have synergistic negative effects on the persistence of eelgrass beds.

Description: Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is used widely to analyse single volcanic glass shards from Quaternary tephra deposits for stratigraphic correlation. As yet, no generally accepted protocol for these analyses exists and published methods report significant differences in crater size and calibration strategies. Using Ca as the ‘internal standard’ (CaI.S.), and not SiI.S., for the analysis of rhyolitic glass can cause significant problems, because of ablation of (i) Ca-rich phenocrysts, notably ‘ubiquitous’ plagioclase, but also calcic-amphibole, apatite and allanite or (ii) mounting epoxy resin which can contribute to the Ca internal standard signal. Using CaI.S. can cause underreporting of many elements which concentrate in Ca-rich phenocrysts, making their ablation difficult to recognize, but when using SiI.S., no such underreporting occurs. Additionally, larger ablation craters (50mm diameter) potentially incorporate even small volumes of phenocryst material, whereas smaller craters (〈20mm diameter) more frequently miss phenocrysts. Thus, for the LA-ICP-MS analysis of rhyolitic glass shards, smaller ablation craters should be employed and calibrated using SiI.S., allowing recognition and removal of analyses incorporating Ca-rich phenocrysts and avoiding issues related to the ablation of the mounting resin.

Description: The use of stable isotope analysis in ecological and wildlife studies is rapidly increasing. Studies include evaluating flow of nutrients in ecosystems and studying dietary composition of individual animals. Several mixing models have been developed to evaluate the relative contribution of different foods to the diet of consumers. All these mixing models require that all prey types will be significantly different in bivariate space. This requirement usually poses a problem in analyzing data of stable isotope ratios because sample sizes in most studies are small and seldom normally distributed. We propose a randomization test that we based on the K nearest-neighbor approach. Results from our simulations of power revealed that the K nearest-neighbor test appears to have high power even with small sample sizes and comparatively low displacement. The K nearest-neighbor test described here provides the preliminary statistical analysis necessary for the use of the mixing models, and therefore is a new, powerful tool for analyzing stable isotope data. In evaluating the test performance on data collected from American martens (Martes americana) and their prey on Chichagof Island, Southeast Alaska, we were able to reject our null hypothesis that all samples of prey were drawn from identical populations (P = 0.05). A program written in Pascal or S-Plus is available from the authors to evaluate the K nearest-neighbor statistic for several groups.

Description: We analyse the fluid flow regime within sediments on the Eastern levee of the modern Mississippi Canyon using 3D seismic data and downhole logging data acquired at Sites U1322 and U1324 during the 2005 Integrated Ocean Drilling Program (IODP) Expedition 308 in the Gulf of Mexico. Sulphate and methane concentrations in pore water show that sulphate–methane transition zone, at 74 and 94 m below seafloor, are amongst the deepest ever found in a sedimentary basin. This is in part due to a basinward fluid flow in a buried turbiditic channel (Blue Unit, 1000 mbsf), which separates sedimentary compartments located below and above this unit, preventing normal upward methane flux to the seafloor. Overpressure in the lower compartment leads to episodic and focused fluid migration through deep conduits that bypass the upper compartment, forming mud volcanoes at the seabed. This may also favour seawater circulation and we interpret the deep sulphate–methane transition zones as a result of high downward sulphate fluxes coming from seawater that are about 5–10 times above those measured in other basins. The results show that geochemical reactions within shallow sediments are dominated by seawater downwelling in the Mars-Ursa basin, compared to other basins in which the upward fluid flux is controlling methane-related reactions. This has implications for the occurrence of gas hydrates in the subsurface and is evidence of the active connection between buried sediments and the water column.

Description: This paper contains the results of an extensive isotopic study of United States Geological Survey GSD-1G and MPI-DING reference glasses. Thirteen different laboratories were involved using high-precision bulk (TIMS, MC-ICP-MS) and microanalytical (LA-MC-ICP-MS, LA-ICP-MS) techniques. Detailed studies were performed to demonstrate the large-scale and small-scale homogeneity of the reference glasses. Together with previously published isotopic data from ten other laboratories, preliminary reference and information values as well as their uncertainties at the 95% confidence level were determined for H, O, Li, B, Si, Ca, Sr, Nd, Hf, Pb, Th and U isotopes using the recommendations of the International Association of Geoanalysts for certification of reference materials. Our results indicate that GSD-1G and the MPI-DING glasses are suitable reference materials for microanalytical and bulk analytical purposes.

Description: Transverse sections of otoliths from Atlantic cod Gadus morhua from the Baltic Sea revealed narrow growth increments. The widths of these increments corresponded to daily increments from fish with known otolith growth rates and were therefore assumed to be daily increments. They exhibited a distinct pattern with increasing distance from the primary primordium. A series of zones with clearly distinguishable increments, first with increasing then with decreasing widths in a dome-shaped pattern, were separated by zones where no regular increment structure was visible. Increment width seemed to be tightly coupled to the annual cycle in environmental temperature at a depth of 30–60 m, where G. morhua predominantly reside. Between 135 and 200 increments occurred within the different zones, with a non-significant trend towards lower increment numbers and widths with distance from the primary primordium of the otolith. Increment formation apparently ceased at temperatures 〈 5–6° C, but growth during the cold months corresponded closely with estimated growth rates. The increment patterns seemed to reflect annual cycles in environmental temperature, and the count of the increment cycles may thus be a promising tool for the determination of the true age of Baltic G. morhua.

Description: In situ experiments were run with the seastar Asterias rubens to investigate the influence of epibiosis on predation preferences. Mussels (Mytilus edulis) monospecifically fouled by different epibiont species (the barnacle Balanus improvisus, the red filamentous alga Ceramium strictum, the sponge Halichondria panicea and the hydrozoan Laomedea flexuosa) and macroscopically clean mussels were exposed and seastar predation was monitored by SCUBA. Asterias rubens preferred macroscopical unfouled mussels as prey. Fouling generally reduced predation pressure on the mussel hosts (associational resistance). Barnacles protected mussels less efficiently than hydrozoans or algae. We hypothesize that in top-down controlled communities this influence of epibiosis on predation pressure should affect mussel community patterns. A survey of natural mussel-epibiont distribution in the presence or absence of A. rubens showed that the prevalence of differently fouled mussels differed between predation-exposed and predation-protected habitats. Natural mussel-epibiont associations reflected the preferential predation of the major local predators. Additionally, higher epibiotic diversity and evenness could be observed at locations accessible to benthic predators as compared with habitats protected from predation. As blue mussels and seastars are important structuring and controlling elements in the shallow water community of Kiel Fjord, major consequences of epibiosis on the entire system are discussed.

Description: Newly hatched Baltic cod Gadus morhua larvae are typically found at depths 〉60 m. This is a region of low light and prey availability, hence generating the hypothesis that larvae have to migrate from hatching depth to the surface layer to avoid starvation and improve their nutritional condition. To test this hypothesis, Baltic cod larvae were sampled during the spawning seasons of 1994 and 1995 with depth-resolving multiple opening/closing nets. Each larva was aged by otolith readings and its RNA/DNA ratio was determined as a measure of nutritional condition. The RNA/DNA ratios of these larvae aged 2-25 days (median 10 days) ranged from 0.4 to 6.2, corresponding to levels exhibited by starving and fast-growing larvae in laboratory calibration studies (starvation, protein growth rate, Gpi= -12.2% day−1; fastgrowing larvae, Gpi=14.1%day−1) respectively. Seventy per cent of the field caught larvae had RNA/DNA ratios between the mean values found for starving and fed laboratory larvae. Only larvae aged 8-11 days had higher mean RNA/DNA ratios above 45 m than below (t-test, P〈0.05). However, the instantaneous protein growth rates were significantly higher for all larval age groups in the surface layers (t-test, P〈0.05). Starving larvae were found in all depths sampled (10-85 m), whereas growing larvae (positive Gpi) were restricted to samples taken shallower than 45 m. These superior growth rates above 45 m corroborate the hypothesis and imply that migration to the shallow water layers is a prerequisite for good nutritional condition, growth and survival of Baltic cod larvae. The frequent occurrence of cod larvae older than 8 days in the deep water in poor condition suggests that a proportion of the larvae will die from Starvation in the deep layers of the Baltic Sea.

Description: The relative roles of temperature and food availability on the seasonal and daily growth of whitefish Coregonus lavaretus larvae were investigated in the oligotrophic peri-alpine Lake Annecy, France. During the spring from 2004 to 2007, surface water temperature and density of potential zooplankton prey were monitored, and 2688 larvae were caught and measured. In addition, the daily growth of 130 larvae was estimated retrospectively by investigating the microstructure of their otoliths. Temperature played the predominant role in controlling both seasonal and daily growth of early larvae. In contrast, the abundance of Mesocyclops leuckarti and larval density was only slightly correlated to larval growth, suggesting no food limitation nor strong interindividual competition over the study period. Overall, these findings run counter to concerns about potential food limitation, but sound a warning about the potential impact of climate change on fish ecology and fisheries management.

Description: Understanding the ecological mechanisms that underlie species diversity decline in response to environmental change has become an urgent objective in current ecological research. Not only direct (lethal) effects on single species but also indirect effects altering biotic interactions between species within and across trophic levels comprise the driving force of ecosystem change. In an experimental marine benthic microalgae–grazer system we tested for indirect effects of moderate temperature change on algal diversity by manipulation of temperature, nutrient supply and grazer density. In our model system warming did not exert indirect effects on microalgal diversity via effects on resource competition. However, moderate warming strengthened consumer control and thereby indirectly affected algal community structure which ultimately resulted in decreased diversity. Only in low temperature and low nutrient regimes did the antagonizing mechanisms of bottom–up and top–down regulation establish a balancing effect on algal diversity within 29 days (corresponding to 15–29 algae generations). Effects of thermal habitat change did not appear before 9–18 algae generations, which points to the relevance of longer-term experiments and ecological monitoring in order to separate transient biotic responses and subtle changes of community dynamics in consequence to global change.

Description: Molybdenum concentration and δ98/95Mo values for NIST SRM 610 and 612 (solid glass), NIST SRM 3134 (lot 891307; liquid) and IAPSO seawater reference material are presented based on comparative measurements by MC-ICP-MS performed in laboratories at the Universities of Bern and Oxford. NIST SRM 3134 and NIST SRM 610 and 612 were found to have identical and homogeneous 98Mo/95Mo ratios at a test portion mass of 0.02 g. We suggest, therefore, that NIST SRM 3134 should be used as reference for the δ–Mo notation and to employ NIST SRM 610 or 612 as solid silicate secondary measurement standards, in the absence of an isotopically homogeneous solid geological reference material for Mo. The δ98/95MoJMC Bern composition (Johnson Matthey ICP standard solution, lot 602332B as reference) of NIST SRM 3134 was 0.25 ± 0.09‰ (2s). Based on five new values, we determined more precisely the mean open ocean δ98/95MoSRM 3134 value of 2.09 ± 0.07‰, which equals the value of δ98/95MoJMC Bern of 2.34 ± 0.07‰. We also refined the Mo concentration data for NIST SRM 610 to 412 ± 9 μg g−1 (2s) and NIST SRM 612 to 6.4 ± 0.7 μg g−1 by isotope dilution. We propose these concentration data as new working values, which allow for more accurate in situ Mo determination using laser ablation ICP-MS or SIMS.

Description: Individual migration behaviour during the juvenile and adult life phase of the anadromous twaite shad Alosa fallax in the Elbe estuary was examined using otolith Sr:Ca and Ba:Ca profiles. Between hatching and the end of the first year of life, juveniles showed two migration patterns. Pattern one exhibited a single downstream migration from fresh water to the sea with no return into fresh water. In contrast, pattern two showed a first migration into the sea, then a return into fresh water and, finally, a second downstream migration into marine water. This first report of migration plasticity for A. fallax points to different exposure times to estuarine threats depending on the migration strategy. In adults, high Sr:Ca and low Ba:Ca in the majority of individuals confirmed prior reports of a primarily marine habitat use. Patterns reflecting spawning migrations were rarely observed on otoliths, possibly due to the short duration of visits to fresh water.

Description: Process length variation of cysts of the dinoflagellate Protoceratium reticulatum (Claparède et Lachmann) Bütschli in surface sediments from the North Pacific was investigated. The average process length showed a significant inverse relation to annual seawater density: σt annual = −0.8674 × average process length + 1029.3 (R2 = 0.84), with a standard error of 0.78 kg m−3. A sediment trap study from Effingham Inlet in British Columbia revealed the same relationship between average process length and local seawater density variations. In the Baltic–Skagerrak region, the average process length variation was related significantly to annual seawater density: σt annual = 3.5457 × average process length − 993.28 (R2 = 0.86), with a standard error of 3.09 kg m−3. These calibrations cannot be reconciled, which accentuates the regional character of the calibrations. This can be related to variations in molecular data (small subunit, long subunit and internal transcribed spacer sequences), which show the presence of several genotypes and the occurrence of pseudo-cryptic speciation within this species.

Description: In this study, the impact of oceanic data assimilation on ENSO simulations and predictions is investigated. The authors’ main objective is to compare the impact of the assimilation of sea level observations and three-dimensional temperature measurements relative to each other. Three experiments were performed. In a control run the ocean model was forced with observed winds only, and in two assimilation runs three-dimensional temperatures and sea levels were assimilated one by one. The root-mean-square differences between the model solution and observations were computed and heat content anomalies of the upper 275 m compared to each other. Three ensembles of ENSO forecasts were performed additionally to investigate the impact of data assimilation on ENSO predictions. In a control ensemble a hybrid coupled ocean–atmosphere model was initialized with observed winds only, while either three-dimensional temperatures or sea level data were assimilated during the initialization phase in two additional forecast ensembles. The predicted sea surface temperature anomalies were averaged over the eastern equatorial Pacific and compared to observations. Two different objective skill measures were computed to evaluate the impact of data assimilation on ENSO forecasts. The authors’ experiments indicate that sea level observations contain useful information and that this information can be inserted successfully into an oceanic general circulation model. It is inferred from the forecast ensembles that the benefit of sea level and temperature assimilation is comparable. However, the positive impact of sea level assimilation could be shown more clearly when the forecasted temperature differences rather than the temperature anomalies themselves were compared with observations.

Description: The seasonal cycle over the tropical Pacific simulated by 11 coupled ocean–atmosphere general circulation models (GCMs) is examined. Each model consists of a high-resolution ocean GCM of either the tropical Pacific or near-global means coupled to a moderate- or high-resolution atmospheric GCM, without the use of flux correction. The seasonal behavior of sea surface temperature (SST) and eastern Pacific rainfall is presented for each model. The results show that current state-of-the-art coupled GCMs share important successes and troublesome systematic errors. All 11 models are able to simulate the mean zonal gradient in SST at the equator over the central Pacific. The simulated equatorial cold tongue generally tends to be too strong, too narrow, and extend too far west. SSTs are generally too warm in a broad region west of Peru and in a band near 10°S. This is accompanied in some models by a double intertropical convergence zone (ITCZ) straddling the equator over the eastern Pacific, and in others by an ITCZ that migrates across the equator with the seasons; neither behavior is realistic. There is considerable spread in the simulated seasonal cycles of equatorial SST in the eastern Pacific. Some simulations do capture the annual harmonic quite realistically, although the seasonal cold tongue tends to appear prematurely. Others overestimate the amplitude of the semiannual harmonic. Nonetheless, the results constitute a marked improvement over the simulations of only a few years ago when serious climate drift was still widespread and simulated zonal gradients of SST along the equator were often very weak.

Description: At least half of the global warming observed during the 20th century of about 0.8°C is of anthropogenic origin and mostly due to enhanced atmospheric carbon dioxide levels in response to the burning of fossil fuels. The climate problem is therefore closely linked to the way we produce energy. Climate models predict a massive warming by the end of the century should global greenhouse gas emissions not be strongly reduced. The Intergovernmental Panel on Climate Change (IPCC) reports that the warming can amount to up to 4°C in a worst case scenario, which would be unprecedented in speed and extent in man's history. This can lead to an increase of extreme weather events and a rise of global sea level by up to 1m. A less known impact of increasing atmospheric carbon dioxide is ocean acidification, as the oceans take up large amounts of carbon dioxide. Ocean acidification potentially threatens marine life and global food production.

Description: Landscape connectivity can increase the capacity of communities to maintain their function when environments change by promoting the immigration of species or populations with adapted traits. However, high immigration may also restrict fine tuning of species compositions to local environmental conditions by homogenizing the community. Here we demonstrate that dispersal generates such a tradeoff between maximizing local biomass and the capacity of model periphyton metacommunities to recover after a simulated heat wave. In non-disturbed metacommunities, dispersal decreased the total biomass by preventing differentiation in species composition between the local patches making up the metacommunity. On the contrary, in metacommunities exposed to a realistic summer heat wave, dispersal promoted recovery by increasing the biomass of heat tolerant species in all local patches. Thus, the heat wave reorganized the species composition of the metacommunities and after an initial decrease in total biomass by 38.7%, dispersal fueled a full recovery of biomass in the restructured metacommunities. Although dispersal may decrease equilibrium biomass, our results highlight that connectivity is a key requirement for the response diversity that allows ecological communities to adapt to climate change through species sorting.

Description: This paper focuses on the marine foundation eelgrass species, Zostera marina, along a gradient from the northern Baltic Sea to the north-east Atlantic. This vast region supports a minimum of 1480 km2 eelgrass (maximum 〉2100 km2), which corresponds to more than four times the previously quantified area of eelgrass in Western Europe. Eelgrass meadows in the low salinity Baltic Sea support the highest diversity (4–6 spp.) of angiosperms overall, but eelgrass productivity is low (〈2 g dw m-2 d-1) and meadows are isolated and genetically impoverished. Higher salinity areas support monospecific meadows, with higher productivity (3–10 g dw m-2 d-1) and greater genetic connectivity. The salinity gradient further imposes functional differences in biodiversity and food webs, in particular a decline in number, but increase in biomass of mesograzers in the Baltic. Significant declines in eelgrass depth limits and areal cover are documented, particularly in regions experiencing high human pressure. The failure of eelgrass to re-establish itself in affected areas, despite nutrient reductions and improved water quality, signals complex recovery trajectories and calls for much greater conservation effort to protect existing meadows. The knowledge base for Nordic eelgrass meadows is broad and sufficient to establish monitoring objectives across nine national borders. Nevertheless, ensuring awareness of their vulnerability remains challenging. Given the areal extent of Nordic eelgrass systems and the ecosystem services they provide, it is crucial to further develop incentives for protecting them.

Description: Molybdenum isotopes are increasingly widely applied in Earth Sciences. They are primarily used to investigate the oxygenation of Earth's ocean and atmosphere. However, more and more fields of application are being developed, such as magmatic and hydrothermal processes, planetary sciences or the tracking of environmental pollution. Here, we present a proposal for a unifying presentation of Mo isotope ratios in the studies of mass-dependent isotope fractionation. We suggest that the Mo-98/95 of the NIST SRM 3134 be defined as +0.25. The rationale is that the vast majority of published data are presented relative to reference materials that are similar, but not identical, and that are all slightly lighter than NIST SRM 3134. Our proposed data presentation allows a direct first-order comparison of almost all old data with future work while referring to an international measurement standard. In particular, canonical Mo-98/95 values such as +2.3 parts per thousand for seawater and -0.7 parts per thousand for marine Fe-Mn precipitates can be kept for discussion. As recent publications show that the ocean molybdenum isotope signature is homogeneous, the IAPSO ocean water standard or any other open ocean water sample is suggested as a secondary measurement standard, with a defined Mo-98/95 value of +2.34 +/- 0.10 parts per thousand (2s).

Description: This study investigated growth, condition and development of American eels Anguilla rostrata that were introduced into a European river to estimate their competitive potential in a non-native habitat. Results demonstrate that A. rostrata develops normally in European waters and successfully competes with the native European eel Anguilla anguilla. In addition, A. rostrata appears to be more susceptible to the Asian swimbladder nematode Anguillicola crassus than A. anguilla and could support the further propagation of this parasite. Detected differences in fat content and gonad mass between Anguilla species are assumed to reflect species-specific adaptations to spawning migration distances. This study indicates that A. rostrata is a potential competitor for the native fauna in European fresh waters and suggests strict import regulations to prevent additional pressure on A. anguilla and a potential further deterioration of its stock situation.

Description: Ecosystem functioning is affected by horizontal (within trophic groups) and vertical (across trophic levels) biodiversity. Theory predicts that the effects of vertical biodiversity depend on consumer specialization. In a microcosm experiment, we investigated ciliate consumer diversity and specialization effects on algal prey biovolume, evenness and composition, and on ciliate biovolume production. The experimental data was complemented by a process-based model further analyzing the ecological mechanisms behind the observed diversity effects. Overall, increasing consumer diversity had no significant effect on prey biovolume or evenness. However, consumer specialization affected the prey community. Specialist consumers showed a stronger negative impact on prey biovolume and evenness than generalists. The model confirmed that this pattern was mainly driven by a single specialist with a high per capita grazing rate, consuming the two most productive prey species. When these were suppressed, the prey assemblage became dominated by a less productive species, consequently decreasing prey biovolume and evenness. Consumer diversity increased consumer biovolume, which was stronger for generalists than for specialists and highest in mixed combinations, indicating that consumer functional diversity, i.e. more diverse feeding strategies, increased resource use efficiency. Overall, our results indicate that consumer diversity effects on prey and consumers strongly depend on species-specific growth and grazing rates, which may be at least equally important as consumer specialization in driving consumer diversity effects across trophic levels.

Description: We compared the development and fatty acid content of the harpacticoid copepods Tachidius discipes and Tisbe sp. fed with different microalgal species (Dunaliella tertiolecta, Rhodomonas sp., Phaeodactylum tricornutum, Isochrysis galbana and a concentrate of Pavlova sp.), which differed in cell size and fatty acid composition. Tisbe could develop in 11 days with every alga to the same average stage, whereas Tachidius developed poorly when fed with Isochrysis and Dunaliella. Feeding with Phaeodactylum resulted in a fast development of both copepods at low algal concentrations. However, reproduction was higher with Rhodomonas as food than with the other algae. Fatty acid compositions of copepods were influenced by their food source, but both were able to convert docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) from precursors. Tachidius fed with Rhodomonas or Phaeodactylum was closest to the DHA/EPA/arachidonic acid (ARA) ratio of 10 : 5 : 1 considered optimal for some marine fish larvae. Tachidius showed similar development and reproduction capacity as Tisbe, but requested higher absolute fatty acid contents in the diet. Tisbe was superior in the utilization of bacteria as additional food source and the bioconversion of precursor fatty acids. Phaeodactylum and Rhodomonas are recommendable food sources for both copepod species, but Phaeodactylum is more easily cultured.

Description: El Niño–Southern Oscillation (ENSO) in the Pacific and the analogous Atlantic Niño mode are generated by processes involving coupled ocean–atmosphere interactions known as the Bjerknes feedback. It has been argued that the Atlantic Niño mode is more strongly damped than ENSO, which is presumed to be closer to neutrally stable. In this study the stability of ENSO and the Atlantic Niño mode is compared via an analysis of the Bjerknes stability index. This index is based on recharge oscillator theory and can be interpreted as the growth rate for coupled modes of ocean–atmosphere variability. Using observational data, an ocean reanalysis product, and output from an ocean general circulation model, the individual terms of the Bjerknes index are calculated for the first time for the Atlantic and then compared to results for the Pacific. Positive thermocline feedbacks in response to wind stress forcing favor anomaly growth in both basins, but they are twice as large in the Pacific compared to the Atlantic. Thermocline feedback is related to the fetch of the zonal winds, which is much greater in the equatorial Pacific than in the equatorial Atlantic due to larger basin size. Negative feedbacks are dominated by thermal damping of sea surface temperature anomalies in both basins. Overall, it is found that both ENSO and the Atlantic Niño mode are damped oscillators, but the Atlantic is more strongly damped than the Pacific primarily because of the weaker thermocline feedback.

Description: Analysis of maximum depth of occurrence of 11 952 marine fish species shows a global decrease in species number (N) with depth (x; m): log10 N = -0·000422x + 3·610000 (r(2)  = 0·948). The rate of decrease is close to global estimates for change in pelagic and benthic biomass with depth (-0·000430), indicating that species richness of fishes may be limited by food energy availability in the deep sea. The slopes for the Classes Myxini (-0·000488) and Actinopterygii (-0·000413) follow this trend but Chondrichthyes decrease more rapidly (-0·000731) implying deficiency in ability to colonize the deep sea. Maximum depths attained are 2743, 4156 and 8370 m for Myxini, Chondrichthyes and Actinopterygii, respectively. Endemic species occur in abundance at 7-7800 m depth in hadal trenches but appear to be absent from the deepest parts of the oceans, 〉9000 m deep. There have been six global oceanic anoxic events (OAE) since the origin of the major fish taxa in the Devonian c. 400 million years ago (mya). Colonization of the deep sea has taken place largely since the most recent OAE in the Cretaceous 94 mya when the Atlantic Ocean opened up. Patterns of global oceanic circulation oxygenating the deep ocean basins became established coinciding with a period of teleost diversification and appearance of the Acanthopterygii. Within the Actinopterygii, there is a trend for greater invasion of the deep sea by the lower taxa in accordance with the Andriashev paradigm. Here, 31 deep-sea families of Actinopterygii were identified with mean maximum depth 〉1000 m and with 〉10 species. Those with most of their constituent species living shallower than 1000 m are proposed as invasive, with extinctions in the deep being continuously balanced by export of species from shallow seas. Specialized families with most species deeper than 1000 m are termed deep-sea endemics in this study; these appear to persist in the deep by virtue of global distribution enabling recovery from regional extinctions. Deep-sea invasive families such as Ophidiidae and Liparidae make the greatest contribution to fish fauna at depths 〉6000 m.

Description: We propose that ocean conditions of the Near Islands in the western Atleutian Arc mimic those of the shallow continental shelf of the eastern Bering Sea to the extent that the marine community, including assemblages of forage fishes and their avian predators, has disinctly coastal characteristics. In contrast, marine avifauna and their prey at neighbouring Buldir Island are distinctly oceanic. For example, at the Near Islands, the ratio of thick-billed to common murres, Uria lomvia and U. aalge, is low and black.legged kittiwakes, Rissa tridacytla, but not red-legged kittiwakes, R. brevirostris, nest there. Diets of murres and kittiwkaes are dominated by sand lance, Ammodytes hexapterus, an abundant coastal species. At Buldir Island, thick-billed murres greatly outnumber common murres, red-legged kittiwakes and black-legged kittiwakes are both abundant, and diets of the birds consist primarily of oceanic squid and lantern-fish (Myctophidae). This mesoscale difference in food webs is apparently a consequence of the local physiography. A broad escarpment on the Near physiographic block creates a comparatively expansive, shallow, shelf-like habitat around the Near Islands, where a pelagic community typical of coastal regions flourished. Buldir Island is the only emergent feature of the Buldir physiographic block, with little shallow water surrounding it and, apparently, little opportunity for other than oceanic species to exist. Patterns in the distribution of fishes, and thus of sea birds, throughout the Atleutian Islands might be largely explained by the relationship between physical environments and food webs. In the larger context of fisheries oceanography, this model for the Aleutian Islands improves our ability to interpret physical and biological heterogeneity in the ocean and its relationship to regional community dynamics and trends in the abundance and productivity of individual species at higher tropic levels.

Description: A number of rapid climate oscillations occur during the Lateglacial–Early Holocene, 15–8 ka BP period and a well-developed tephrostratigraphy in association with these oscillations increases the possibilities to correlate climate archives around the North Atlantic. This paper presents a tephrostratigraphy for Fosen peninsula, Central Norway. Both the Vedde Ash ca.12.1 ka BP and the Saksunarvatn Ash ~10.3 ka BP are important isochrones for correlations of Late Quaternary palaeoenvironmental records in the North Atlantic region and have been assigned ages in GICC05. Beside these tephras we have also identified a new tephra, the Fosen Tephra, with a Borrobol-type geochemistry that occurs above both the Vedde Ash and the Saksunarvatn Ash with an age ~10.2 ka BP. Several tephras with Borrobol-type geochemistry have been identified around the North Atlantic. One group is the Borrobol/Penifiler tephras dated to Greenland Interstadial-1 and another group is dated to the Early Holocene. We suggest that some of the Early Holocene Borrobol-type tephras and the Fosen Tephra may actually be the same layer. If so, the Fosen Tephra is spread over a large area of the North Atlantic and has the potential to become an important marker for short-term climate variability in Scandinavia and in the northern hemisphere.

Description: The temperature relationship of routine metabolic rate (Rr) of non-feeding, non-growing Coregonus lavaretus larvae between 2 and 15°C is characterized by Q10-values ranging from l.8-2.45. The rate of growth, based on weight determinations, of first-feeding larvae amounted to 3.5, 7.6 and 9.4% day-1 at 5, 10 and 12°C respectively, from which Q10-values between 4.0 and 4.8 can be calculated. The rate of increase of muscle mass between 5 and 10°C, based on the determination of the cross-sectional area of inner muscle fibres, resulted in a Q10-value of 4.5. Water temperature influenced the pattern of growth of the inner muscle fibres. At hatching, after 360 day degrees, total muscle mass of larvae reared at 4 and 8°C was independent of temperature, but at 4°C the rate of mass increase owed more to hyperplasia (increase in fibre number) than to hypertrophy (increase in fibre mass), whereas at 8°C the opposite was the case. The calculation of power budgets (including the metabolic cost of growth) of first-feeding larvae yielded net conversion efficiencies (K2) increasing with temperature from 46.3% at 5°C to 54.7% at 12°C. Comparing our data with literature data two general conclusions can be drawn. (1) In first-feeding larvae the net, but not the gross, conversion efficiency of food energy increases with temperature. This is due to net energy input being characterized by a much higher Q10-value than energy expenditures. (2) In embryos of freshwater fish so far investigated hyperplasia plays a greater role in the increase of fibre mass than hypertrophy at the lower temperature, whereas in embryos of marine fish hyperplasia prevails at the higher temperature. It is suggested that this discrepancy correlates with the high concentration of free amino acids in the eggs of marine species which provide an additional, easily available, source of metabolic energy absent in freshwater species.

Description: In experimental metacommunities with marine benthic microalgae, we tested whether heat stress changes effects of connectivity and habitat heterogeneity on metacommunity structure and functioning, by manipulating a simulated heat wave, dispersal frequency and a light intensity gradient. We found that all measures of mean local and regional diversity and community biomass significantly declined after the heat wave and showed no sign of recovery. Additionally, dispersal decreased diversity and increased dominance in both the heat stressed and control communities. Together the heat wave and high dispersal frequency induced a dominance shift by spreading a temperature tolerant but low yielding species from its source patches with low light intensity across the metacommunity, an effect that increased with time. Although different species became dominant at high dispersal frequency with and without the heat wave, the shift towards a temperature tolerant species was not sufficient to maintain total community biomass. Thus, short-term disturbance may cause longer-term loss of ecosystem function due to dominance shifts in the composition of communities. This study illustrates the importance of employing multispecies approaches when attempting to predict responses of communities to environmental changes.

Description: In this paper the performance of the global coupled general circulation model (CGCM) ECHO-2, which was integrated for 10 years without the application of flux correction, is described. Although the integration is rather short, strong and weak points of this CGCM can be clearly identified, especially in view of the model's performance of the annual cycle in the tropical Pacific. The latter is simulated with more success relative to the earlier version, ECHO-I. A better representation of the low-level stratus clouds in the atmosphere model associated with a reduction in the shortwave radiative flux at the air-sea interface improved the coupled model's performance in the southeastern tropical oceans, with a strongly reduced warm bias in these regions. Modifications in the atmospheric convection scheme also eliminated the AGCM's tendency to simulate a double ITCZ, and this behavior is maintained in the CGCM simulation. Finally, a new numerical scheme for active tracer advection in the ocean model strongly reduced the numerical mixing, which seems to enhance considerably the level of interannual variability in the equatorial Pacific. One weak point is an overall cold bias in the Tropics and midlatitudes, which typically amounts to 1°C in open ocean regions. Another weak point is the still too strong equatorial cold tongue, which penetrates too far into the western equatorial Pacific. Although this model deficiency is not as pronounced as in ECHO-1, the too strong cold tongue reduces the level of interannual rainfall variability in the western and central equatorial Pacific. Finally, the interannual fluctuations in equatorial Pacific sea surface temperatures (SSTs) are too equatorially trapped, a problem that is also found in ocean-only simulations. Overall, however, the authors believe that the ECHO-2 CGCM has been considerably improved relative to ECHO-1.

Description: The microbial communities were analyzed from commercially available dried dairy nutraceutical products, including 4 brands of dried colostrum, 2 brands of dried whey, and 1 brand of nonfat dry milk. A culture‐dependent 16S rRNA sequencing approach was utilized to elucidate the identity of individual isolates recovered from each dried dairy product. Approximately 69% of all bacterial isolates were members the genus of Bacillus, while approximately 14% of all bacterial isolates were identified as members of the genus Pseudomonas. Members of the Kocuria, Microbacterium, and Enterococcus genera were identified as well.