ALBERT

Description: Using a portable gas analyzer system, the geogenic gas regime below and around an ancient gate to hell at Hierapolis/Phrygia was characterized. The site was first described by Strabo and Plinius as a gate to the underworld. During centuries, it attracted even ancient tourists. In a grotto below the temple of Pluto, CO2 was found to be at deadly concentrations of up to 91%. Astonishingly, these vapors are still emitted in concentrations that nowadays kill insects, birds, and mammals. The concentrations of CO2 escaping from the mouth of the grotto to the outside atmosphere are still in the range of 4–53% CO2 depending on the height above ground level. They reach concentrations during the night that would easily kill even a human being within a minute. These emissions are thought to reflect the Hadean breath and/or the breath of the hellhound Kerberos guarding the entrance to hell. The origin of the geogenic CO2 is the still active seismic structure that crosses the old town of ancient Hierapolis as part of the Babadag fracture zone. Our measurements confirm the presence of geogenic CO2 in concentrations that explain ancient stories of killed bulls, rams, and songbirds during religious ceremonies. They also strongly corroborate that at least in the case of Hierapolis, ancient writers like Strabo or Plinius described a mystic phenomenon very exactly without much exaggeration. Two thousand years ago, only supernatural forces could explain these phenomena from Hadean depths whereas nowadays, modern techniques hint to the well-known phenomenon of geogenic CO2 degassing having mantle components with relatively higher helium and radon concentrations.

Description: Continental rifting and ocean basin formation can be observed at the present day in the Red Sea, which is used as the modern analogue for the formation of mid-ocean ridges. Competing theories for how spreading begins—either by quasi-instantaneous formation of a whole spreading segment or by initiation of spreading at multiple discrete “nodes” separated by thinned continental lithosphere—have been put forward based, until recently, on the observations that many seafloor features and geophysical anomalies (gravity, magnetics) along the axis of the Red Sea appeared anomalous compared to ancient and modern examples of ocean basins in other parts of the world. The latest research shows, however, that most of the differences between the Red Sea Rift (RSR) and other (ultra)slow-spreading mid-ocean ridges can be related to its relatively young age and the presence and movement of giant submarine salt flows that blanket large portions of the rift valley. In addition, the geophysical data that was previously used to support the presence of continental crust between the axial basins with outcropping oceanic crust (formerly named “spreading nodes”) can be equally well explained by processes related to the sedimentary blanketing and hydrothermal alteration. The observed spreading nodes are not separated from one another by tectonic boundaries but rather represent “windows” onto a continuous spreading axis which is locally inundated and masked by massive slumping of sediments or evaporites from the rift flanks. Volcanic and tectonic morphologies are comparable to those observed along slow and ultra-slow spreading ridges elsewhere and regional systematics of volcanic occurrences are related to variations in volcanic activity and mantle heat flow. Melt-salt interaction due to salt flows, that locally cover the active spreading segments, and the absence of large detachment faults as a result of the nearby Afar plume are unique features of the RSR. The differences and anomalies seen in the Red Sea still may be applicable to all young oceanic rifts, associated with plumes and/or evaporites, which makes the Red Sea a unique but highly relevant type example for the initiation of slow rifting and seafloor spreading and one of the most interesting targets for future ocean research.

Description: Coral reefs in the Red Sea belong to the most diverse and productive reef ecosystems worldwide, although they are exposed to strong seasonal variability, high temperature, and high salinity. These factors are considered stressful for coral reef biota and challenge reef growth in other oceans, but coral reefs in the Red Sea thrive despite these challenges. In the central Red Sea high temperatures, high salinities, and low dissolved oxygen on the one hand reflect conditions that are predicted for ‘future oceans’ under global warming. On the other hand, alkalinity and other carbonate chemistry parameters are considered favourable for coral growth. In coral reefs of the central Red Sea, temperature and salinity follow a seasonal cycle, while chlorophyll and inorganic nutrients mostly vary spatially, and dissolved oxygen and pH fluctuate on the scale of hours to days. Within these strong environmental gradients micro- and macroscopic reef communities are dynamic and demonstrate plasticity and acclimatisation potential. Epilithic biofilm communities of bacteria and algae, crucial for the recruitment of reef-builders, undergo seasonal community shifts that are mainly driven by changes in temperature, salinity, and dissolved oxygen. These variables are predicted to change with the progression of global environmental change and suggest an immediate effect of climate change on the microbial community composition of biofilms. Corals are so-called holobionts and associate with a variety of microbial organisms that fulfill important functions in coral health and productivity. For instance, coral-associated bacterial communities are more specific and less diverse than those of marine biofilms, and in many coral species in the central Red Sea they are dominated by bacteria from the genus Endozoicomonas. Generally, coral microbiomes align with ecological differences between reef sites. They are similar at sites where these corals are abundant and successful. Coral microbiomes reveal a measurable footprint of anthropogenic influence at polluted sites. Coral-associated communities of endosymbiotic dinoflagellates in central Red Sea corals are dominated by Symbiodinium from clade C. Some corals harbour the same specific symbiont with a high physiological plasticity throughout their distribution range, while others maintain a more flexible association with varying symbionts of high physiological specificity over depths, seasons, or reef locations. The coral-Symbiodinium endosymbiosis drives calcification of the coral skeleton, which is a key process that provides maintenance and formation of the reef framework. Calcification rates and reef growth are not higher than in other coral reef regions, despite the beneficial carbonate chemistry in the central Red Sea. This may be related to the comparatively high temperatures, as indicated by reduced summer calcification and long-term slowing of growth rates that correlate with ocean warming trends. Indeed, thermal limits of abundant coral species in the central Red Sea may have been exceeded, as evidenced by repeated mass bleaching events during previous years. Recent comprehensive baseline data from central Red Sea reefs allow for insight into coral reef functioning and for quantification of the impacts of environmental change in the region.

Description: The Laptev and Eastern Siberian shelves are the world’s broadest shallow shelf systems. Large Siberian rivers and coastal erosion of up to meters per summer deliver large volumes of terrestrial matter into the Arctic shelf seas. In this chapter we investigate the applicability of Ocean Colour Remote Sensing during the ice-free summer season in the Siberian Laptev Sea region. We show that the early summer river peak discharge may be traced using remote sensing in years characterized by early sea-ice retreat. In the summer time after the peak discharge, the spreading of the main Lena River plume east and north-east of the Lena River Delta into the shelf system becomes hardly traceable using optical remote sensing methods. Measurements of suspended particulate matter (SPM) and coloured dissolved organic matter (cDOM) are of the same magnitude in the coastal waters of Buor Khaya Bay as in the Lena River. Match-up analyses of in situ chlorophyll-a (Chl-a) show that standard Medium Resolution Imaging Spectrometer (MERIS) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived Chl-a is not a valid remote sensing product for the coastal waters and the inner shelf region of the Laptev Sea. All MERIS and MODIS-derived Chl-a products are overestimated by at least a factor of ten, probably due to absorption by the extraordinarily high amount of non-algal particles and cDOM in these coastal and inner-shelf waters. Instead, Ocean Colour remote sensing provides information on wide-spread resuspension over shallows and lateral advection visible in satellite-derived turbidity. Satellite Sea Surface Temperature (SST) data clearly show hydrodynamics and delineate the outflow of the Lena River for hundreds of kilometres out into the shelf seas.

Description: The size of current plankton image datasets renders manual classification virtually infeasible. The training of models for machine classification is complicated by the fact that a large number of classes consist of only a few examples. We employ the recently introduced weight imprinting technique in order to use the available training data to train accurate classifiers in absence of enough examples for some classes. The model architecture used in this work succeeds in the identification of plankton using machine learning with its unique challenges, i.e. a limited number of training examples and a severely skewed class size distribution. Weight imprinting enables a neural network to recognize small classes immediately without re-training. This permits the mining of examples for novel classes.

Description: This review article aims to provide an overview and insight into the most relevant aspects of wind energy development and current state-of-the-art. The industry is in a very mature stage, so it seems to be the right time to take stock of the relevant areas of wind energy use for power generation. For this review, the authors considered the essential aspects of the development of wind energy technology: research, modeling, and prediction of wind speed as an energy source, the technology development of the plants divided into the mechanical and electrical systems and the plant control, and finally the optimal plant operation including the maintenance strategies. The focus is on the development in Europe, with a partial focus on Germany. The authors are employees of the Fraunhofer Institutes, Institute for Energy Economics and Energy Systems Technology and Institute for Wind Energy Systems, who have contributed to the development of this technology for decades.

Description: The Alpine orogeny is well recorded onshore and offshore by tectonic inversion of the Mesozoic rift basins. Large scale linear seamounts (more than 250 km long and with up to 5 km of uplift) involving oceanic and continental lithosphere were carried on top of thrusts, such as the Gorringe seamount and the Estremadura Spur in the SouthWest and West Iberia Margin, respectively. The SouthWest Iberia Margin also recorded the westward migration of the Gibraltar Oceanic slab as the westwards propagation of the Neo-Tethys subduction. Rotation of the tectonic compression from NW-SE to WNW-ESE inPliocene times caused the development of large scale dextral wrench faults as the present day Africa-Iberia plate boundary. Neotectonics of this plate boundary caused large to mega-scale destructive earthquakes and tsunamis.

Description: Hydrothermal circulation at mid-ocean ridges and assimilation of hydrothermally altered crust or hydrothermal fluids by rising magma can be traced by measuring chlorine (Cl) excess in erupted lavas. The Red Sea Rift provides a unique opportunity to study assimilation of hydrothermally altered crust at an ultra-slow spreading ridge (maximum 1.6 cm yr−1 full spreading rate) by Cl, due to its saline seawater (40–42‰, cf. 35‰ in open ocean water), the presence of (hot) brine pools (up to 270‰ salinity and 68 °C) and the thick evaporite sequences that flank the young rift. Absolute chlorine concentrations (up to 1300 ppm) and Cl concentrations relative to minor or trace elements of similar mantle incompatibility (e.g., K, Nb) are much higher in Red Sea basalts than in basalts from average slow spreading ridges. Mantle Cl/Nb concentrations can be used to calculate the Cl-excess, above the magmatic Cl, that is present in the samples. Homogeneous within-sample Cl concentrations, high Cl/H2O, the decoupling of Cl-excess from other trace elements and its independence of the presence of highly saline seafloor brines at the site of eruption indicate that Cl is not enriched at the seafloor. Instead we find basaltic Cl-excess to be spatially closely correlated with evidence of hydrothermal activity, suggesting that deeper assimilation of hydrothermal Cl is the dominant Cl-enrichment process. A proximity of samples to both evaporite outcrops and bathymetric signs of volcanism on the seafloor enhance Cl-excess in basalts. The basaltic Cl-excess can be used as a tracer together with new bathymetric maps as well as indications of hydrothermal venting (hot brine pools, metalliferous Hydrothermal circulation at mid-ocean ridges and assimilation of hydrothermally altered crust or hydrothermal fluids by rising magma can be traced by measuring chlorine (Cl) excess in erupted lavas. The Red Sea Rift provides a unique opportunity to study assimilation of hydrothermally altered crust at an ultra-slow spreading ridge (maximum 1.6 cm yr−1 full spreading rate) by Cl, due to its saline seawater (40–42‰, cf. 35‰ in open ocean water), the presence of (hot) brine pools (up to 270‰ salinity and 68 °C) and the thick evaporite sequences that flank the young rift. Absolute chlorine concentrations (up to 1300 ppm) and Cl concentrations relative to minor or trace elements of similar mantle incompatibility (e.g., K, Nb) are much higher in Red Sea basalts than in basalts from average slow spreading ridges. Mantle Cl/Nb concentrations can be used to calculate the Cl-excess, above the magmatic Cl, that is present in the samples. Homogeneous within-sample Cl concentrations, high Cl/H2O, the decoupling of Cl-excess from other trace elements and its independence of the presence of highly saline seafloor brines at the site of eruption indicate that Cl is not enriched at the seafloor. Instead we find basaltic Cl-excess to be spatially closely correlated with evidence of hydrothermal activity, suggesting that deeper assimilation of hydrothermal Cl is the dominant Cl-enrichment process. A proximity of samples to both evaporite outcrops and bathymetric signs of volcanism on the seafloor enhance Cl-excess in basalts. The basaltic Cl-excess can be used as a tracer together with new bathymetric maps as well as indications of hydrothermal venting (hot brine pools, metalliferous sediments) to predict where hydrothermal venting or now inactive hydrothermal vent fields can be expected. Sites of particular interest for future hydrothermal research are the Mabahiss Deep, the Thetis-HadarbaHatiba Deeps and Shagara-Aswad-Erba Deeps (especially their large axial domes), and Poseidon Deep. Older hydrothermal vent fields may be present at the Nereus and Suakin Deeps. These sites significantly increase the potential of hydrothermal vent field prospection in the Red Sea.

Description: The deep-sea brines of the Red Sea are unusual extreme environments and form characteristically steep gradients across the brine-seawater interfaces. Due to their unusual nature and unique combination of physical-chemical conditions these interfaces provide an interesting source of new findings in the fields of geochemistry, geology, microbiology, biotechnology, virology, and general biology. The current chapter summarizes recent and new results in the study of geochemistry and life at the interfaces of brine-filled deeps of the Red Sea.

Description: This paper addresses visual navigation of autonomous underwater vehicles (AUVs) with and without a given map, where the latter is called Simultaneous Localization and Mapping (SLAM). We summarize the challenges and opportunities in underwater environments that make visual navigation different from land navigation and also briefly survey the current state-of-the-art in this area. Then as a position paper we argue why many of these challenges could be met by a proper modeling of uncertainties in the SLAM representation. This would in particular allow the SLAM algorithm to thoroughly handle the ambiguity between “I see the same feature again.”, “I see a different but similar looking feature.” and “The environment has changed and the feature moved.”.

Description: The application of acoustic techniques, such as multibeam echosounders, has permitted the identification of Maltese submarine landscapes and landforms that were progressively inundated during the postglacial sea-level rise. Remarkably, geomorphological features due to fluvial, gravity-induced and karst processes that took place under former subaerial conditions can be clearly recognised on the present seafloor around the Maltese archipelago, and they were only slightly modified by sea action during the postglacial transgression phases. The analysis of the submerged landforms described in this chapter is crucial for understanding the evolution of the Maltese Islands during the last ca. 20,000 years.

Description: The study presents the results of continuous measurements of carbon dioxide concentration in the atmospheric surface layer at Tiksi and Cape Baranov Arctic stations over the period of August 2010–May 2017 and over the whole 2016, respectively. The amplitude of diurnal variations in the CO2 concentration in Tiksi from June to September is 1.1 ± 1.3, 2.4 ± 2.0, 4.1 ± 2.3, and 2.0 ± 2.4 ppm. Diurnal variations in CO2 at Cape Baranov station are absent. The observed seasonal variations in the CO2 concentration are compared with the data of the MBL empirical model for the marine atmospheric boundary layer of the Arctic region. In 2016, the difference between the observed and model concentrations at Tiksi and Cape Baranov stations amounted to 1.7 and 0.5 ppm, respectively, in winter and −3.0 and −1.9 ppm, respectively, in summer. It is shown that wildfires in Siberia caused a long synchronous increase in the CO2 concentration by 20 ppm in Tiksi and by 15 ppm at Cape Baranov station.

Description: The water of Atlantic origin (Atlantic water) is of special importance for the formation of the hydrological regime of the Arctic Ocean and provides a “building material” for the main water masses in the surface and intermediate layers. Atlantic water are structurally included to the Arctic Transpolar System (ATS); it is a multicomponent physical object whose state defines the role of the Arctic Ocean in the planetary climate. The recent advances in the Atlantic water research are discussed, in particular, the role of Atlantic water in the Arctic sea ice reduction. Particular attention is paid to the possible activation of feedbacks in ATS that may result in an accelerated Arctic sea ice loss recorded after 2007.

Description: Three most common Arctic foraminiferal species of the family Cassidulinidae from the Laptev Sea sediment cores were analyzed for paleoenvironmental reconstructions. This paleontological study is focused on morphological characteristics of apertural elements and the wall structure. The species Cassidulina neoteretis is considered an indicator of the Atlantic influence in contrast to the Arctic species Cassidulina reniforme and Islandiella norcrossi.

Description: The ecology and taxonomy of Islandiella norcrossi (Cushman, 1933), a typical representative of the Arctic calcareous benthic foraminifers, are analyzed based on microfossils from the Late Pleistocene-Holocene deposits of the Laptev Sea. This species is distributed on the shelf and continental slope of the Arctic seas, and indicates normal marine conditions with a seasonal ice cover and cold Arctic water masses. The species is also associated with a high seasonal productivity in sea-ice marginal zone. Tests are abundant in the Laptev Sea sediments, and show some variability in the size and shape of chambers, which was possibly caused by harsh environmental conditions of the Arctic (limited period of growth and reproduction); aberrant forms with an additional aperture being also present. The population contains tests of macrospherical and microspherical generations, as well as juveniles.

Description: Dome ports act as spherical windows in underwater housings through which a camera can observe objects in the water. As compared to flat glass interfaces, they do not limit the field of view, and they do not cause refraction of light observed by a pinhole camera positioned exactly in the center of the dome. Mechanically adjusting a real lens to this position is a challenging task, in particular for those integrated in deep sea housings. In this contribution a mechanical adjustment procedure based on straight line observations above and below water is proposed that allows for accurate alignments. Additionally, we show a chessboard-based method employing an underwater/above-water image pair to estimate potentially remaining offsets from the dome center to allow refraction correction in photogrammetric applications. Besides providing intuition about the severity of refraction in certain settings, we demonstrate the methods on real data for acrylic and glass domes in the water.

Description: We discuss the results of measurements in the region of Cape Baranov (the Severnaya Zemlya archipelago) of the set of physicochemical characteristics of atmospheric aerosol: aerosol optical depth, aerosol and black carbon concentrations, elemental and ion compositions of aerosol, organic and elemental carbon contents in aerosol, as well as the isotopic composition of carbon in the aerosol and snow samples. It is shown that the average values of most aerosol characteristics, measured in April–June 2018, are a little lower than in the Arctic settlement Barentsburg (Spitsbergen archipelago) and several-fold smaller than in the south of Western Siberia in the same period.

Description: Plastic has become indispensable for human life. When plastic debris is discarded into waterways, these items can interact with organisms. Of particular concern are microscopic plastic particles (microplastics) which are subject to ingestion by several taxa. This review summarizes the results of cutting-edge research about the interactions between a range of aquatic species and microplastics, including effects on biota physiology and secondary ingestion. Uptake pathways via digestive or ventilatory systems are discussed, including (1) the physical penetration of microplastic particles into cellular structures, (2) leaching of chemical additives or adsorbed persistent organic pollutants (POPs), and (3) consequences of bacterial or viral microbiota contamination associated with microplastic ingestion. Following uptake, a number of individual-level effects have been observed, including reduction of feeding activities, reduced growth and reproduction through cellular modifications, and oxidative stress. Microplastic-associated effects on marine biota have become increasingly investigated with growing concerns regarding human health through trophic transfer. We argue that research on the cellular interactions with microplastics provide an understanding of their impact to the organisms’ fitness and, therefore, its ability to sustain their functional role in the ecosystem. The review summarizes information from 236 scientific publications. Of those, only 4.6% extrapolate their research of microplastic intake on individual species to the impact on ecosystem functioning. We emphasize the need for risk evaluation from organismal effects to an ecosystem level to effectively evaluate the effect of microplastic pollution on marine environments. Further studies are encouraged to investigate sublethal effects in the context of environmentally relevant microplastic pollution conditions.

Description: Stable carbon isotopes of sediment organic matter (δ13COM) are widely applied in paleoenvironmental studies. Interpretations of δ13COM, however, remain challenging and factors that influence δ13COM may not apply across all lakes. Common explanations for stratigraphic shifts in δ13COM include changes in lake productivity or changes in inputs of allochthonous OM. We investigated the influence of different oxygen conditions (oxic versus anoxic) on the δ13COM values in the sediments of Lake Tiefer See. We analysed (1) a long sediment core from the deepest part of the lake, (2) two short, sediment–water interface cores from shallower water depths, and (3) OM in the water column, i.e. from sediment traps. Fresh OM throughout the entire water column showed a relatively constant δ13COM value of approximately − 30.5‰. Similar values, about − 31‰, were obtained for well-varved sediments in both the long and short, sediment–water interface cores. In contrast, δ13COM values from non-varved sediments in all cores were significantly less negative (− 29‰). The δ13COM values in the sediment–water interface cores from different water depths differ for sediments of the same age, if oxygen conditions at the time of deposition were different at these sites, as suggested by the state of varve preservation. Sediments deposited from AD 1924 to 1980 at 62 m water depth are varved and exhibit δ13COM values around − 31‰, whereas sediments of the same age in the core from 35 m water depth are not varved and show less negative δ13COM values of about − 29‰. The relation between varve occurrence and δ13COM values suggests that δ13COM is associated with oxygen conditions because varve preservation depends on hypolimnetic anoxia. A mechanism that likely influences δ13COM is selective degradation of OM under oxic conditions, such that organic components with more negative δ13COM are preferably decomposed, leading to less negative δ13COM values in the remaining, undegraded OM pool. Greater decomposition of OM in non-varved sediments is supported by lower TOC concentrations in these deposits (~ 5%) compared to well-varved sediments (~ 15%). Even in lakes that display small variations in productivity and terrestrial OM input through time, large spatial and temporal differences in hypolimnetic oxygen concentrations may be an important factor controlling sediment δ13COM.

Description: In den tropischen und subtropischen Meeren existieren in mittleren Tiefen riesige sauerstoffarme Zonen. Im Zuge des Klimawandels dehnen sie sich immer stärker aus. Auch in Küstenregionen entstehen durch Stickstoffbelastung aus der Landwirtschaft lebensfeindliche Zonen ohne Sauerstoff – mit verheerenden Folgen für das marine Ökosystem.

Description: The invasive round goby has established a viable population within 9 years of its first introduction to Lithuanian coastal waters (SE Baltic Sea). During its expansion phase, abundances increased 23-fold, which led to the near complete eradication of its main prey, the blue mussel, at 〈 20 m depth. The round goby population showed a stabilizing trend after blue mussel biomass was depleted; however, their abundance has not declined. The round goby feeds efficiently on newly settled mollusks, causing a severe constraint for blue mussel recovery. Changes in blue mussel availability and size structure induced a dietary shift in wintering long-tailed duck towards fish prey. An energetically dense food source sustains a good body condition in long-tailed ducks, however the change in trophic position (from 3.1 to 4.3 trophic level) suggests the potential for a reduction in their carrying capacity. Results from this study also show that coastal habitats with low and unpredictable population dynamics of blue mussel become less attractive wintering sites for long-tailed duck in the Baltic Sea. We also document a cascading effect of invasive species in the food web.

Description: We introduce a new parallelizable numerical multiscale method for advection-dominated problems as they often occur in engineering and geosciences. State of the art multiscale simulation methods work well in situations in which stationary and elliptic scenarios prevail but are prone to fail when the model involves dominant lower order terms which is common in applications. We suggest to overcome the associated difficulties through a reconstruction of subgrid variations into a modified basis by solving many independent (local) inverse problems that are constructed in a semi-Lagrangian step. Globally the method looks like a Eulerian method with multiscale stabilized basis. The method is extensible to other types of Galerkin methods, higher dimensions, nonlinear problems and can potentially work with real data. We provide examples inspired by tracer transport in climate systems in one and two dimensions and numerically compare our method to standard methods.

Description: Natural polysaccharides of marine origin are gaining interest in biomedical applications. Seaweeds are most abundant source of polysaccharides, as alginates, agar and agarose as well as Carrageenans. Even cellulose and amylose have been extracted from the macroalgae. Chitin and chitosan are derived from the exoskeleton of marine crustaceans. Interdisciplinary fields involving various science and technology aspects such as cell sciences, biomaterials, medical sciences and engineering are referred to as tissue engineering, which is an upcoming new field intended to replace biological functions in human body. Tissue engineered scaffolds and artificial organs developed by such technique has replace injured parts in human body. Technological advancements have made it possible to obtain active ingredient in marine organisms by controlling the growth and isolation conditions. Present review has focused on progress in discovering and producing new applications of marine polysaccharides in biomedical and tissue engineering.

Description: Differences in habitat and diet between species are often associated with morphological differences. Habitat and trophic adaptation have therefore been proposed as important drivers of speciation and adaptive radiation. Importantly, habitat and diet shifts likely impose changes in exposure to different parasites and infection risk. As strong selective agents influencing survival and mate choice, parasites might play an important role in host diversification. We explore this possibility for the adaptive radiation of Lake Tanganyika (LT) cichlids. We first compare metazoan macroparasites infection levels between cichlid tribes. We then describe the cichlids’ genetic diversity at the major histocompatibility complex (MHC), which plays a key role in vertebrate immunity. Finally, we evaluate to what extent trophic ecology and morphology explain variation in infection levels and MHC, accounting for phylogenetic relationships. We show that different cichlid tribes in LT feature partially non-overlapping parasite communities and partially non-overlapping MHC diversity. While morphology explained 15% of the variation in mean parasite abundance, trophic ecology accounted for 16% and 22% of the MHC variation at the nucleotide and at the amino acid level, respectively. Parasitism and immunogenetic adaptation may thus add additional dimensions to the LT cichlid radiation.

Description: Common problems in state-of-the-art climate models are a cold sea surface temperature (SST) bias in the equatorial Pacific and the underestimation of the two most important atmospheric feedbacks operating in the El Niño/Southern Oscillation (ENSO): the positive, i.e. amplifying wind-SST feedback and the negative, i.e. damping heat flux-SST feedback. To a large extent, the underestimation of those feedbacks can be explained by the cold equatorial SST bias, which shifts the rising branch of the Pacific Walker Circulation (PWC) too far to the west by up to 30°, resulting in an erroneous convective response during ENSO events. Based on simulations from the Kiel Climate Model (KCM) and the 5th phase of Coupled Model Intercomparison Project (CMIP5), we investigate how well ENSO dynamics are simulated in case of underestimated ENSO atmospheric feedbacks (EAF), with a special focus on ocean–atmosphere coupling over the equatorial Pacific. While models featuring realistic atmospheric feedbacks simulate ENSO dynamics close to observations, models with underestimated EAF exhibit fundamental biases in ENSO dynamics. In models with too weak feedbacks, ENSO is not predominantly wind-driven as observed; instead ENSO is driven significantly by a positive shortwave radiation feedback. Thus, although these models simulate ENSO, which in terms of simple indices is consistent with observations, it originates from very different dynamics. A too weak oceanic forcing on the SST via the positive thermocline, the Ekman and the zonal advection feedback is compensated by weaker atmospheric heat flux damping. The latter is mainly caused by a biased shortwave-SST feedback that erroneously is positive in most climate models. In the most biased models, the shortwave-SST feedback contributes to the SST anomaly growth to a similar degree as the ocean circulation. Our results suggest that a broad continuum of ENSO dynamics can exist in climate models and explain why climate models with less than a half of the observed EAF strength can still depict realistic ENSO amplitude.

Description: Diseases increasingly threaten aquaculture of kelps and other seaweeds. At the same time, protection concepts that are based upon application of biocides are usually not applicable, as such compounds would be rapidly diluted in the sea, causing ecological damage. An alternative concept could be the application of immune stimulants to prevent and control diseases in farmed seaweeds. We here present a pilot study that investigated the effects of oligoalginate elicitation on juvenile and adult sporophytes of Saccharina japonica cultivated in China and on adult sporophytes of Saccharina latissima cultivated in Germany. In two consecutive years, treatment with oligoalginate clearly reduced the detachment of S. japonica juveniles from their substrate curtains during the nursery stage in greenhouse ponds. Oligoalginate elicitation also decreased the density of endobionts and the number of bacterial cells on sporophytes of S. latissima that were cultivated on sea-based rafts. However, the treatment increased the susceptibility of kelp adults to settlement of epibionts (barnacles in Germany and filamentous algal epiphytes in China). In addition, oligoalginate elicitation accelerated the aging of S. japonica adults. Based upon these findings, oligoalginate elicitation could be a feasible way to provide “environmentally friendly” protection of kelp juveniles in nurseries. The same treatment causes not only beneficial, but also unwanted effects in adult kelp sporophytes. Therefore, it is not recommended as a treatment after the juvenile stage is completed. Future tests with other elicitors and other cultivated seaweed species may allow for the development of more feasible applications of targeted defense elicitation in seaweed aquaculture.

Description: The present study details the effects of basin-scale hydrographic characteristics of the Red Sea on the macroecology of Chaetognatha, a major plankton component in the pelagic realm. The hydrographic attributes and circulation of the Red Sea as a result of its limited connection with the northern Indian Ocean make it a unique ecohydrographic region in the world ocean. Here, we aimed to identify the prime determinants governing the community structure and vertical distribution of the Cheatognatha in this ecologically significant world ocean basin. The intrusion of Gulf of Aden Water influenced the Chaetognatha community composition in the south, whereas the overturning circulation altered their vertical distribution in the north. The existence of hypoxic waters (〈 100 µmol kg−1) at mid-depth also influenced their vertical distribution. The detailed evaluation of the responses of the different life stages of Chaetognatha revealed an increased susceptibility of adult individuals to hypoxic waters compared to immature stages. Higher oxygen demands of the adults for the egg and sperm production might have prevented them from inhabiting the oxygen-deficient mid-depth zones. The carbon and nitrogen content of the Copepoda and Chaetognatha communities and the quantification of the predation impact of Chaetognatha on Copepoda based on the feeding rate helped in corroborating the significant trophic link between these two prey–predator taxa. The observed influences of physical and chemical attributes on the distribution of Chaetognatha can be used as a model example for the role of the hydrography on the zooplankton community of the Red Sea.

Description: As coastal areas become increasingly vulnerable to climate change, the study of nearshore sediment textures along the littoral cell of the Medjerda delta in the Gulf of Tunis, southern Mediterranean coast can provide valuable information (i) on the origin (continental or marine) of the sediment, (ii) its transport direction, and (iii) constitutes an important tool in the assessment of coastal sensitivity. A total of 120 sediments samples underwent grain size analysis and statistic parameters have been calculated. These allowed the identification of five different Sedimentary Types (ST). Accordingly, using grain size indexes (i.e. Mz, SKI and Ku), Sediment Trend Analysis (STA) modeling tools were applied to define the seasonal sediment transport pathways throughout the nearshore of the Medjerda sedimentary cell. Results show that grain size distribution (GSD) and STA model pathways are determined by cross-shore geomorphology, location of the sediment-cell, seasonal incident wave and local terrestrial supply. The appearance in an atypical seabed location of the finer (Mo = 0.1 mm) and the coarser STs (Mo = 0.8 mm) can be indicative of human influence since the coarser particles are usually retained by dam structures. Moreover, the bimodality and the increased distribution of mud are also related to the seasonal incident wave winnowing of the historic deltaic plain submerged by the relative rise in sea level. The evolution of the sediment pattern towards a greater proportion of very fine grains indicates a deficit of sediment supply, particularly of the coarser grains, and demonstrates the coastal vulnerability of the Gulf of Tunis due to anthropic effects.

Description: A broad variety of materials of biological origin have been successfully used in recent decades for the removal of pollutants from waters. These biosorbents include natural polymers that play a key role for adsorption. It is therefore critical to understand the physicochemical properties of the chemical groups of these biopolymers. The acid–base properties of biomass are affected by pH, ionic strength and medium composition. Nevertheless, these parameters are not always considered during biosorption studies. According to the literature, less than 3% of biosorption reports include studies on proton binding. Moreover, in 60% of these papers, there is key experimental information missing such as the calibration of the electrodes employed for potentiometric titrations. We consider therefore that there is an important need for reviewing the role of proton binding in biosorption studies. This review outlines the major advances on data interpretation and modelling of proton binding on biosorbents. In addition, we discuss issues concerning the acid–base properties of biosorbents.

Description: Hydrothermal fluids on the modern seafloor are important carriers of base and precious metals in a wide range of volcanic and tectonic settings. The concentrations and distribution, especially of gold and silver, in associated seafloor massive sulfide (SMS) deposits are strongly influenced by variable source rocks, fluid chemistry, and precipitation mechanisms. Compositional data of 130 SMS deposits around the world show a large range of gold and silver grades, in part reflecting strong buffering of the hydrothermal fluids by their host rocks. Geochemical reaction-path modeling shows that in most cases the investigated hydrothermal fluids are undersaturated with gold and silver, and solubilities can be orders of magnitude higher than the Au and Ag concentrations measured in the corresponding fluids. Precipitation of gold during conductive cooling of mid-ocean ridge black smoker (MOR) fluids occurs at low temperatures but can be very rapid, with 〉 90% of the gold deposited in the first 25 °C of cooling below ~ 150 °C. The result is a Zn–Au polymetallic assemblage with Au and Ag deposited at the same time together with Pb and sulfosalts. In ultramafic-dominated (UM) systems, the strongly reduced hydrothermal fluids promote the deposition of gold at higher temperatures and explain the correlation between gold and copper in these deposits. In this case, the lower stability of the AuHS° complex at low ƒO2 (buffered by fayalite, magnetite, and quartz) results in gold deposition at 〉 250 °C with early bornite and chalcopyrite and before sphalerite and silver, producing a high-temperature Cu–Au assemblage. In sediment-hosted (SED) systems, the much higher pH stabilizes Au(HS)2− and keeps gold in solution to very low temperatures, after the precipitation of chalcopyrite, sphalerite, and galena, resulting in Au-poor polymetallic sulfides and very late-stage deposition of gold, commonly with amorphous silica. In arc-related (ARC) systems, gold deposition occurs at somewhat higher temperatures than in the MOR case, in part because the fluids start with higher gold concentrations. This can be explained by probable direct magmatic contributions, and the high ƒO2 of the fluids, which promotes the solubility of gold at the source. During cooling, gold precipitates at about 160 °C with sphalerite, tennantite, silver, and galena, resulting in an Au-rich polymetallic sulfide assemblage. The mixing of hydrothermal fluids with seawater generally causes oxidation and eventually a decrease in the pH at a mixing ratio of 1:1, causing an initial increase in the solubility of gold and silver. This can delay gold deposition from aqueous species to very low temperatures. These complex systematics make prediction of Au and Ag grades difficult. However, important new data are coming to light on the actual concentrations of the precious metals in hydrothermal fluids. In particular, the input of magmatic volatiles and leaching of pre-existing gold can lead to significant increases in the Au and Ag concentrations of the venting fluids and earlier deposition. In several cases, it appears that at least part of the gold load is present as nanoparticles in suspension, allowing bulk gold concentrations that may be far in excess of liquid saturation. Boiling at the seafloor is now widely observed, even at great water depths close to the critical point of seawater. Model calculations of phase separation during boiling show the competing effects on gold solubility of H2, H2S, and CO2 partitioning into the vapor, which can result in highly variable gold-to-base metal ratios in the deposits. Flashing of the vent fluids into steam at high temperatures is also commonly observed and can lead to spectacular Au grades, with a strong Cu–Au association in the deepest and hottest vents.

Description: The ecological approach to comparative cognition emphasizes that the ecological and social environment are important predictors of cognitive performance. We used this approach to test whether differences in habitat use and social behavior in the facultative Caribbean cleaning goby Elacatinus prochilos predict differences in learning performance in two discriminatory two-choice tasks. This species has two behavioral ecotypes: one that frequently engages in cleaning interactions and inhabits corals in male–female pairs (cleaning gobies) and another that rarely engages in cleaning interactions and inhabits barrel sponges in large groups (sponge-dwellers). We predicted that cleaning gobies would outperform sponge-dwellers in a pattern-cued task, which consisted of identifying the pattern on a plate that consistently provided food, while sponge-dwellers would outperform cleaning gobies in a spatial task, which consisted of identifying the location of the plate. Contrary to our predictions, there was no difference in performance between the two ecotypes. Most of the gobies performed poorly in the pattern-cued task and well in the spatial task. A possible explanation for these results is that the association of a pattern with positive and negative reinforcement may not be a pre-requisite for engaging in cleaning interactions, while spatial skills might be equally required in both ecotypes. Alternatively, the two ecotypes can flexibly adjust to new feeding conditions, which would explain their similar performance in the spatial task. Further research should investigate which aspects of E. prochilos’ social and ecological environment might impose challenges that require spatial cognition and whether individuals can flexibly adjust to new habitats and feeding conditions.

Description: Precipitation in California is modulated by variability in the tropical Pacific associated with El Nino/Southern Oscillation (ENSO): more rainfall is expected during El Nino episodes, and reduced rainfall during La Nina. It has been suggested that besides the shape and location of the sea surface temperature ( SST) anomaly this remote connection depends on the strength and location of the atmospheric convection response in the tropical Pacific. Here we show in a perturbed physics ensemble of the Kiel Climate Model and CMIP5 models that due to a cold equatorial SST bias many climate models are in a La Nina-like mean state, resulting in a too westward position of the rising branch of the Pacific Walker Circulation. This in turn results in a convective response along the equator during ENSO events that is too far west in comparison to observations. This effect of the equatorial cold SST bias is not restricted to the tropics, moreover it leads to a too westward SLP response in the North Pacific and too westward precipitation response that does not reach California. Further we show that climate models with a reduced equatorial cold SST bias have a more realistic representation of the spatial asymmetry of the teleconnections between El Nino and La Nina.

Description: The spatial pattern of the first mode of interannual variability associated with the East Asian summer monsoon (EASM), obtained from a multivariate Empirical Orthogonal Functions (MV-EOF) analysis, corresponds to the Pacific–Japan (PJ) pattern and is referred to as the PJ-mode. The present study investigates the interannual variation of the PJ-mode from the perspective of the intraseasonal timescale. In particular, the impact of the Madden–Julian oscillation (MJO) on the interannual variation of the PJ-mode is investigated. The results show that the MJO has a significant influence on the interannual variation of the PJ-mode mainly in the lower troposphere (850 hPa) and that the former accounts for approximately 11% of the amplitude of the latter. The major part of the contribution comes from a change in frequency of the different phases of the MJO, especially that of MJO phase 6. This suggests that intraseasonal variation of the convection anomalies over the tropical eastern Indian and western Pacific Oceans plays an important role in the interannual variation of the PJ-mode. In addition, MJO phase 7 also contributes to the interannual variability of the PJ-mode, in this case induced by both the change in frequency and the change in circulation anomalies associated with MJO phase 7.

Description: This book includes invited contributions presenting the latest research on the oceanography and environment of the Red Sea. In addition to covering topics relevant to research in the region and providing insights into marine science for non-experts, it is also of interest to those involved in the management of coastal zones and encourages further research on the Red Sea

Description: The nature of the warm climates of the Cretaceous has been enigmatic since the first numerical climate models were run in the late 1970s. Quantitative simulations of the paleoclimate have consistently failed to agree with information from plant and animal fossils and climate sensitive sediments. The ‘cold continental interior paradox’ (first described by DeConto et al. in Barrera E, Johnson C (eds) Evolution of the Cretaceous Ocean/climate system, vol 332. Geological Society of America Special Paper, Boulder, pp 391–406, 1999), has been an enigma, with extensive continental interiors, especially in northeast Asia, modeled as below freezing in spite of plant and other evidence to the contrary. We reconsider the paleoelevations of specific areas, particularly along the northeastern Siberian continental margin, where paleofloras indeed indicate higher temperatures than suggested by current climate models. Evidence for significant masses of ice on land during even the otherwise warmest times of the Cretaceous is solved by reinterpretation of the δ18O record of fossil plankton. The signal interpreted as an increase in ice volume on land is the same as the signal for an increase in the volume of groundwater reservoirs on land. The problem of a warm Arctic, where fossil floras indicate that they never experienced freezing conditions in winter, could not be solved by numerical simulations using higher CO2 equivalent greenhouse gas concentrations. We propose a solution by assuming that paleoelevations were less than today and that there were much more extensive wetlands (lakes, meandering rivers, swamps, bogs) on the continents than previously assumed. Using ~ 8 × CO2 equivalent greenhouse gas concentrations and assuming 50–75% water surfaces providing water vapor as a supplementary greenhouse gas on the continents reduces the meridional temperature gradients. Under these conditions the equatorial to polar region temperature gradients produce conditions compatible with fossil and sedimentological evidence.

Description: Climate model components involve both high-dimensional input and output fields. It is desirable to efficiently generate spatio-temporal outputs of these models for applications in integrated assessment modelling or to assess the statistical relationship between such sets of inputs and outputs, for example, uncertainty analysis. However, the need for efficiency often compromises the fidelity of output through the use of low complexity models. Here, we develop a technique which combines statistical emulation with a dimensionality reduction technique to emulate a wide range of outputs from an atmospheric general circulation model, PLASIM, as functions of the boundary forcing prescribed by the ocean component of a lower complexity climate model, GENIE-1. Although accurate and detailed spatial information on atmospheric variables such as precipitation and wind speed is well beyond the capability of GENIE-1’s energy-moisture balance model of the atmosphere, this study demonstrates that the output of this model is useful in predicting PLASIM’s spatio-temporal fields through multi-level emulation. Meaningful information from the fast model, GENIE-1 was extracted by utilising the correlation between variables of the same type in the two models and between variables of different types in PLASIM. We present here the construction and validation of several PLASIM variable emulators and discuss their potential use in developing a hybrid model with statistical components.

Description: There is a controversy about the origin of the recent decadal Atlantic Meridional Overturning Circulation (AMOC) slowing observed at 26.5°N and concurrent sea surface temperature cooling in the central and eastern mid-latitude North Atlantic. We investigate decadal AMOC slowing events simulated in a multi-millennial preindustrial control integration of the Kiel Climate Model (KCM), providing an estimate of internal AMOC variability. Preindustrial control integrations of 15 models participating in the Coupled Model Intercomparison Project phase 5 also are investigated, as well as historical simulations with them providing estimates of AMOC variability during 1856–2005. It is shown that the recent decadal AMOC decline is still within the range of the models’ internal AMOC variability and thus could be of natural origin. In this case, the decline would represent an extreme realization of internal variability provided the climate models yield realistic levels of AMOC variability. The model results suggest that internal decadal AMOC variability is large, requiring multi-decadal observational records to detect an anthropogenic AMOC signal with high confidence. When analyzing the strongest decadal AMOC slowing events in the KCM, which have amplitudes similar to or larger than the recently observed decadal AMOC decline, the following composite picture emerges: a very strong decadal AMOC decline is preceded by a decadal rise in atmospheric surface pressure over large parts of the mid-latitude North Atlantic. The change in low-level atmospheric circulation drives reduced oceanic heat loss over and diminished upper-ocean salt content in the Labrador Sea. In response, oceanic deep convection and subsequently the AMOC and northward oceanic heat transport weaken, and anomalously cold sea surface temperatures develop in the central and eastern mid-latitude North Atlantic

Description: Climate engineering (CE) deployment would alter prevailing relationships between Earth system variables, making indicators and metrics used so far in the climate change assessment context less appropriate to assess CE measures. Achieving a comprehensive CE assessment requires a systematic and transparent reevaluation of the indicator selection process from Earth system variables. Here, we provide a first step towards such a systematic assessment of changes in correlations between Earth system variables following simulated deployment of different CE methods. We therefore analyze changes in the correlation structure of a broad set of Earth system variables for two conventional climate change scenarios without CE and with three idealized CE model experiments: (i) solar radiation management, (ii) large-scale afforestation, and (iii) ocean alkalinity enhancement. First, we investigate how the three CE scenarios alter prevailing correlations between Earth system variables when compared to an intermediate-high and a business-as-usual future climate change scenario. Second, we contrast the indicators identified for the non-CE climate change scenarios and the indicators identified when all five scenarios are considered. Finally, we use the identified indicator sets for an evaluation of the five climate change scenarios. We find that the additional indicators provide valuable information for the assessment of the CE measures, and their application hence allows for a more comprehensive and a comparative assessment of the mitigation and CE deployment scenarios.

Description: Reproductive systems of rare adult specimens of the deep-sea squid genera Chiroteuthis, Mastigoteuthis, Liocranchia, and Bathoteuthis were collected in 2006 and 2015 in the different research surveys in the Atlantic Ocean between 46 degrees 40'S and 17 degrees 11'N. Whole squids were preserved in 4% buffered formaldehyde solution, subsequently transferred into 70% ethanol and studied in laboratory condition providing initial observations on spawning pattern in these animals. The potential fecundity of Ch. cf. joubini was similar to 45,000-50,000, the maximum egg size was 1.6-1.7 mm, while those of M. agassizii were similar to 8000-16,000 and 1.7-1.9 mm respectively. A maturing female of B. skolops had similar to 4800 eggs of which some similar to 1200 were atretic. The ovary of a spent L. reinhardti contained similar to 116,500 post-ovulatory follicles and no residual egg. Mature females of Chiroteuthis and Mastigoteuthis had spematangia implanted externally in the mantle, whereas Liocranchia had a specialised spermatangia receptacle on the inside of the mantle. Reproductive adaptations of these genera are discussed in relation to spawning habits of other deep-sea squids. Synchronous ovulation was found to be a prevailing type of the gonad development with all eggs being spawned as a single batch, with ot without brooding. In some species, this single batch is not released at once but in several consequent portions exhibiting 'extended synchronous' spawning.

Description: Easter Island is an isolated volcanic island in the Pacific Ocean. Despite the extended knowledge about its origin, flora, and fauna, little is known about the bacterial diversity inhabiting this territory. Due to its isolation, Easter Island can be considered as a suitable place to evaluate microbial diversity in a geographically isolated context, what could shed light on actinobacterial occurrence, distribution, and potential novelty. In the present study, we performed a comprehensive analysis of marine Actinobacteria diversity of Easter Island by studying a large number of coastal sampling sites, which were inoculated into a broad spectrum of different culture media, where most important variations in composition included carbon and nitrogen substrates, in addition to salinity. The isolates were characterized on the basis of 16S ribosomal RNA gene sequencing and phylogenetic analysis. High actinobacterial diversity was recovered with a total of 163 pure cultures of Actinobacteria representing 72 phylotypes and 20 genera, which were unevenly distributed in different locations of the island and sample sources. The phylogenetic evaluation indicated a high degree of novelty showing that 45% of the isolates might represent new taxa. The most abundant genera in the different samples were Micromonospora, Streptomyces, Salinispora, and Dietzia. Two aspects appear of primary importance in regard to the high degree of novelty and diversity of Actinobacteria found. First, the application of various culture media significantly increased the number of species and genera obtained. Second, the geographical isolation is considered to be of importance regarding the actinobacterial novelty found.

Description: Dramatic changes from a cold and dry last glacial to a warm and wet Holocene period intensified the Indian summer monsoon (ISM), resulting in vigorous hydrology and increased terrestrial erosion. Here we present seawater neodymium (Nd) data (expressed in εNd) from Andaman Sea sediments to assess past changes in the ISM and the related impact of Irrawaddy–Salween and Sittoung (ISS) river discharge into the Andaman Sea in the northeastern Indian Ocean. Four major isotopic changes were identified: (1) a gradual increase in εNd toward a more radiogenic signature during the Last Glacial Maximum (22–18 ka), suggesting a gradual decrease in the ISS discharge; (2) a relatively stable radiogenic seawater εNd between 17.2 and 8.8 ka, perhaps related to a stable reduced outflow; (3) a rapid transition to less radiogenic εNd signature after 8.8 ka, reflecting a very wet early–mid-Holocene with the highest discharge; and (4) a decrease in εNd signal stability in the mid–late Holocene. Taking into account the contribution of the ISS rivers to the Andaman Sea εNd signature that changes proportionally with the strengthening (less radiogenic εNd) or weakening (more radiogenic εNd) of the ISM, we propose a binary model mixing between the Salween and Irrawaddy rivers to explain the εNd variability in Andaman Sea sediments. We hypothesize that the Irrawaddy river mainly contributed detrital sediment to the northeastern Andaman Sea for the past 24 ka. Our εNd data shed new light on the regional changes in Indo-Asian monsoon systems when compared with the existing Indian and Chinese paleo-proxy records.

Description: The genus Tabrizicola with its type species and strain Tabrizicola aquatica RCRI19T was previously described as a purely chemotrophic genus of Gram-negative, aerobic, non-motile and rod-shaped bacteria. With the present study, we expand the description of the metabolic capabilities of this genus and the T. aquatica type strain to include chlorophyll-dependent phototrophy. Our results confirmed that T. aquatica, does not grow under anaerobic photoautotrophic or photoheterotrophic conditions. However, the presence of the photosynthesis-related genes pufL and pufM could be demonstrated in the genomes of several Tabrizicola strains. Additionally, photosynthetic pigments (bacteriochlorophyll a) were formed under aerobic, heterotrophic and low light conditions in T. aquatica strain RCRI19T. Furthermore, all the genes necessary for a fully operational photosynthetic apparatus and bacteriochlorophyll a are present in the T. aquatica type strain genome. Therefore, we suggest categorising T. aquatica RCRI19T, isolated from freshwater environment of Qurugöl Lake, as an aerobic anoxygenic phototrophic (AAP) bacterium.

Description: Warming is one of the most dramatic aspects of climate change and threatens future ecosystem functioning. It may alter primary productivity and thus jeopardize carbon sequestration, a crucial ecosystem service provided by coastal environments. Fucus vesiculosus is an important canopy-forming macroalga in the Baltic Sea, and its main consumer is Idotea balthica. The objective of this study is to understand how temperature impacts a simplified food web composed of macroalgae and herbivores to quantify the effect on organic carbon storage. The organisms were exposed to a temperature gradient from 5 to 25 °C. We measured and modeled primary production, respiration, growth and epiphytic load on the surface of Fucus and respiration, growth and egestion of Idotea. The results show that temperature affects physiological responses of Fucus and Idotea separately. However, Idotea proved more sensitive to increasing temperatures than the primary producers. The lag between the collapse of the grazer and the decline of Fucus and epiphytes above 20 °C allows an increase of carbon storage of the primary productivity at higher temperatures. Therefore, along the temperature gradient, the simplified food web stores carbon in a non-monotonic way (reaching minimum at 20 °C). Our work stresses the need of considering the combined metabolic performance of all organisms for sound predictions on carbon circulation in food webs.

Description: This study applied the Systems Approach Framework (SAF) to address the issue of declining Atlantic cod fishery in coastal areas. Interviews of 58 fishers from 26 harbours and meetings with national fisheries organisations and managers revealed the perception of an offshore movement of coastal cod. Numerical modelling based on fishing survey data did not substantiate these perceptions in the data-poor coastal waters. However, Data Storage Tag (DST) information combined with bottom sea water temperature data from the spatio-temporal hydrodynamic Baltic Sea Ice-Ocean Model showed changes in potential cod habitat distribution in the Skagerrak-Kattegat and western Baltic from 1979 to 2016. Subsequently, cod habitats were defined in three categories: (i) potentially suitable (T 〈= 12 degrees C); (ii) episodic (12 〈 T 〈= 16 degrees C); and (iii) unsuitable (T 〉 16 degrees C). The environmental changes were linked to the socio-economic component of cod fishery. Cod catches (weight and monetary value) were retrieved using logbook information and data from the Vessel Monitoring System (VMS, 2005-2016) and the Automatic Identification System (AIS, 2006-2016). General additive modelling significantly showed the largest proportion of catches took place in the potentially suitable habitat whereas catches were lower in the episodic habitat and rare in the unsuitable habitat. The results of this first large-scale SAF application are highly valuable for adapting existing fisheries management by: (i) providing information on habitat shrinkage for Maximum Sustainable Yield (MSY) based stock assessments; (ii) adding a spatio-temporal dimension for coastal productivity relative to the vessel-based Individual Transferable Quota (ITQ) system; and (iii) providing a predictive scenario simulation tool for sustainable management under changing environmental conditions.

Description: The enactment of the Water Framework Directive (WFD) initiated scientific efforts to develop reliable methods for comparing prevailing lake conditions against reference (or nonimpaired) states, using the state of a set biological elements. Drawing a distinction between impaired and natural conditions can be a challenging exercise. Another important aspect is to ensure that water quality assessment is comparable among the different Member States. In this context, the present paper offers a constructive critique of the practices followed during the WFD implementation in Greece by pinpointing methodological weaknesses and knowledge gaps that undermine our ability to classify the ecological quality of Greek lakes. One of the pillars of WDF is a valid lake typology that sets ecological standards transcending geographic regions and national boundaries. The national typology of Greek lakes has failed to take into account essential components. WFD compliance assessments based on the descriptions of phytoplankton communities are oversimplified and as such should be revisited. Exclusion of most chroococcal species from the analysis of cyanobacteria biovolume in Greek lakes/reservoirs and most reservoirs in Spain, Portugal, and Cyprus is not consistent with the distribution of those taxa in lakes. Similarly, the total biovolume reference values and the indices used in classification schemes reflect misunderstandings of WFD core principles. This hampers the comparability of ecological status across Europe and leads to quality standards that are too relaxed to provide an efficient target for the protection of Greek/transboundary lakes such as the ancient Lake Megali Prespa.

Description: The order Botryosphaeriales includes many latent fungal pathogens with a wide range of woody hosts. The taxonomy of these pathogens has been difficult due to the use of poorly informing markers in phylogenetic analyses and the lack of good morphological characters. Many genera and families in this order have not yet been systematically studied in different hosts and from different regions. In this study, a total of 29 fungal strains from the Aplosporellaceae and Botryosphaeriaceae were isolated from branches or twigs with symptoms of canker and dieback disease in Mount Yudu of China. Morphology and multigene analyses (ITS, LSU and TEF1-α) indicated five distinct lineages, including Aplosporella javeedii, Botryosphaeria dothidea, Diplodia quercicola sp. nov., Phaeobotryon aplospora sp. nov. and Phaeobotryon rhois. Diplodia quercicola is characterized by multiloculate conidiomata, producing oblong to cylindrical, thick-walled, hyaline, aseptate conidia. Phaeobotryon aplospora is characterized by pulvinate, multiloculate conidiomata, producing ellipsoid to oblong, brown, aseptate conidia. The new species differ from related species phylogenetically and ecologically and in morphological features.

Description: We have studied iron (Fe)-isotope signals in particles (〉 0.22 µm) and the dissolved phase (〈 0.22 µm) in two subarctic, boreal rivers, their estuaries and the adjacent sea in northern Sweden. Both rivers, the Råne and the Kalix, are enriched in Fe and organic carbon (up to 29 µmol/L and up to 730 µmol/L, respectively). Observed changes in the particulate and dissolved phase during spring flood in May suggest different sources of Fe to the rivers during different seasons. While particles show a positive Fe-isotope signal during winter, during spring flood, the values are negative. Increased discharge due to snowmelt in the boreal region is most times accompanied by flushing of the organic-rich sub-surface layers. These upper podzol soil layers have been shown to be a source for Fe-organic carbon aggregates with a negative Fe-isotope signal. During winter, the rivers are mostly fed by deep groundwater, where Fe occurs as Fe(oxy)hydroxides, with a positive Fe-isotope signal. Flocculation during initial estuarine mixing does not change the Fe-isotope compositions of the two phases. Data indicate that the two groups of Fe aggregates flocculate diversely in the estuaries due to differences in their surface structure. Within the open sea, the particulate phase showed heavier δ56Fe values than in the estuaries. Our data indicate the flocculation of the negative Fe-isotope signal in a low salinity environment, due to changes in the ionic strength and further the increase of pH.

Description: The climate system can potentially switch from one stable state to another. The closer a system is to a bifurcation point (i.e., ‘tipping point’), the more likely it is that even small perturbations can force the system to experience a state shift, e.g., a collapsing Atlantic meridional overturning circulation (AMOC) and associated cooling in parts of the North Atlantic. Here, we present an abrupt state transition from a warm to a cold North Atlantic climate state with expanded sea ice during an orbitally forced transient Holocene simulation performed with the Community Climate System Model version 3. The state transition is associated with a weakening of the AMOC by about 33% in this simulation. The changing background climate induced by slow external orbital forcing plays an important role for the abrupt climate shift. The model allows the identification of regions and variables that play a key role for a potential climate transition and show early-warning signals. Increase in autocorrelation and standard deviation as well as trends in skewness especially for sea-surface salinity in the northern North Atlantic are identified as robust early-warning signals, whereas no early-warning signals are found in the time series of the AMOC stream function.

Description: Beside its global effects, climate change is manifested in many regionally pronounced features mainly resulting from changes in the oceanic and atmospheric circulation. Here we investigate the influence of the North Atlantic SST on shaping the winter-time response to global warming. Our results are based on a long-term climate projection with the Max Planck Institute Earth System Model (MPI-ESM) to investigate the influence of North Atlantic sea surface temperature pattern changes on shaping the atmospheric climate change signal. In sensitivity experiments with the model’s atmospheric component we decompose the response into components controlled by the local SST structure and components controlled by global/remote changes. MPI-ESM simulates a global warming response in SST similar to other climate models: there is a warming minimum—or ”warming hole”—in the subpolar North Atlantic, and the sharp SST gradients associated with the Gulf Stream and the North Atlantic Current shift northward by a few a degrees. Over the warming hole, global warming causes a relatively weak increase in rainfall. Beyond this, our experiments show more localized effects, likely resulting from future SST gradient changes in the North Atlantic. This includes a significant precipitation decrease to the south of the Gulf Stream despite increased underlying SSTs. Since this region is characterised by a strong band of precipitation in the current climate, this is contrary to the usual case that wet regions become wetter and dry regions become drier in a warmer climate. A moisture budget analysis identifies a complex interplay of various processes in the region of modified SST gradients: reduced surface winds cause a decrease in evaporation; and thermodynamic, modified atmospheric eddy transports, and coastal processes cause a change in the moisture convergence. The changes in the the North Atlantic storm track are mainly controlled by the non-regional changes in the forcing. The impact of the local SST pattern changes on regions outside the North Atlantic is small in our setup.

Description: Solar signals in the atmosphere and the ocean, especially in tropopause temperatures and lower stratospheric water vapour are investigated using recent observational and reanalyses data sets for the period from 1958 through 2013. Previous observational and modeling studies demonstrated solar influences in the lower stratosphere resembling a positive Northern Annular Mode due to the top-down mechanism involving enhanced solar UV radiation in the stratosphere during solar maxima and dynamical amplification mechanisms in the atmosphere. We found that these stratospheric changes might propagate down to the troposphere and become zonally asymmetric with characteristic pressure and wind pattern over the North Atlantic and North Pacific. Such changes in tropospheric circulation are related to anomalous positive SST anomalies in the central Pacific which resemble an El Niño Modoki event. We show for the first time with ocean reanalysis data that these SST anomalies are amplified by a positive feedback through oceanic subsurface currents and heat transport in the equatorial Pacific. Anomalous warm SSTs in the equatorial central Pacific change the zonal SST gradient and lead to anomalous westerly winds and currents in the western Pacific and easterly winds and currents in the eastern Pacific. This indicates a convergence and less upwelling and therefore enhances the positive SST anomalies in the equatorial central Pacific. Such a positive feedback results in a peak of El Niño Modoki events about 2 years after the solar maximum. These solar-induced signals in the ocean in turn modify the circulation and convection in the troposphere, resulting in lagged solar signals of anomalous high tropopause heights and negative anomalies in tropopause temperatures as well as in lower stratospheric water vapour over the equatorial Pacific which are in agreement with a time evolving solar-induced El Niño Modoki-like SST pattern. We demonstrate a solar modulation of intrinsic decadal climate variability over the Pacific which is amplified by positive feedbacks between the ocean and the atmosphere.

Description: Dosidicus gigas (the Humboldt squid) is a widely distributed and ecologically important predator in the eastern Pacific Ocean, but its mating behaviour is poorly understood. Individuals of this species have undergone a drastic change in size at maturity in the last years. We investigated mating activity of Humboldt squid in the Gulf of California in 2013, 2014, and 2015 by quantifying spermatangia deposited in the tissue of the buccal area. In 2015, we encountered the smallest mean mantle length of mature specimens recorded to date in the Gulf of California. In all years, numerous males were encountered that had been mated by other males. Spermatangia in males were deposited on the tissue in similar numbers and in the same location as normally occurs in females (the buccal area), suggesting that male-to-male mating behaviour is similar to male-to-female. This behaviour is referred to as same-sex sexual behaviour and has been described for various taxa, including other cephalopods. Overall similarity in mating frequency between males and females and in body size of mated individuals (in 2015) suggests non-discriminative and brief encounters with body size being a cue for mating. This mating strategy may be beneficial for males, as Humboldt squid live in groups where competition for mates is likely high. The energetic costs of male-to-male mating events may be counterbalanced by the fitness profits of indiscriminate mating behaviour.

Description: Gelatinous zooplankton (GZ) such as medusae, ctenophores, siphonophores, pyrosomes and salps are important components of oceanic pelagic communities and small calycophoran siphonophores (CS) are typically abundant at shallow depths. The Sargasso Sea spawning area of the Atlantic catadromous freshwater eels has a regular pattern of shallow autumn to spring temperature fronts. There is limited information about the southern Sargasso Sea GZ fauna, and it is not known which species are distributed across these frontal zones. Plankton samples from a survey of larval European eel (Anguilla anguilla) abundance in March and April 2017 using an Isaacs-Kidd Midwater Trawl (0–300 m, 35 stations, three transects) were used to examine the distribution and abundance of net-captured CS and other GZ species in relation to oceanographic characteristics. More than 2200 specimens of 15 taxa were sub-sampled, with five CS (Abylopsis tetragona, A. eschscholtzii, Chelophyes appendiculata, Eudoxoides spiralis and E. mitra) dominating catches at every station. GZ were most abundant around the 22 and 24 °C isotherms, and higher abundances of CS in the north were correlated with lower water temperature. The widespread presence of CS across the European eel spawning area is consistent with a recent study detecting their DNA sequences in the gut contents of young eel larvae collected in the Sargasso Sea, suggesting CS material was either eaten directly or as part of ingested marine snow particles. The present study shows that both types of organisms occupy the southern Sargasso Sea during the European eel spawning season.

Description: Climate change has been altering the ocean environment, affecting as a consequence the biological communities including microorganisms. We performed a mesocosm experiment to test whether biodiversity loss caused by one stressor would influence plankton community sensitivity to a subsequent stressor, as envisioned in Vinebrooke's multiple stressor concept. A natural Baltic Sea diatom-dominated phytoplankton assemblage was used as a model system where we examined whether a preceding heat shock would affect the community's response to changing salinity. Initially, the community was treated by a short-term temperature increase of 6 °C, which resulted in a loss of species compared to the control. Thereafter, the control and the heat-shocked communities were subject to a salinity change (- 5 psu, control, + 5 psu). The species Skeletonema dohrnii, Thalassiosira anguste-lineata, Thalassiosira nordenskioeldii, Chaetoceros socialis and Ditylum brightwellii were major components of the control and heat-shocked assemblages (〉 80% of the total biomass). We examined the effect on species composition and biodiversity (morphospecies and operational taxonomic units (OTUs) related to phytoplankton) and on phytoplankton biomass. In addition, we explored the single species response of five dominant diatoms on these environmental perturbations. Our results showed that increased salinity significantly reduced the OTUs richness both in the control and the less diverse heated community as well as the phytoplankton biomass in the heated community. On the other hand, decreased salinity significantly increased species richness and phytoplankton biomass in both communities and OTUs richness in the control community. The five dominant diatoms reached their highest biomass under decreased salinity and responded negatively to increased salinity (lower biomass than ambient salinity). Contrary to Vinebrooke's multiple stressor concept, there was no indication that the heat treatment had altered the community's sensitivity to the salinity stress in our study system.

Description: This manuscript reports the first sightings and collection of the swimming crab Cronius ruber (Lamarck, 1818) on the coast of Madeira Island, Portugal. After the recent record in the Canary Islands, this represents a further step northward on this species’ expansion in distribution in the eastern Atlantic. The crab was first spotted during underwater visual census surveys done by scuba diving in July 2018 and was repeatedly observed during the following months, in different locations on the south coast of Madeira. Analysis of temperature data from several geographic locations where C. ruber is present was performed to assess how thermal regimes and ongoing changes may influence this recent distribution shift. Current temperature trends in Madeira suggest that the arrival and establishment of C. ruber to Madeira might have been facilitated this thermophilic species, adding evidence for the ongoing tropicalization of this area. Finally, the current spread of C. ruber in both Canaries and Madeira island systems highlights the need for a long-term monitoring program targeting this and other non-indigenous species (NIS).

Description: Clonal behavior has been hypothesized to provide an escape from allometric metabolic scaling that limits the maximum mass achieved by a single individual. Here, we demonstrate the capacity of a wide-spread, non-native sea anemone to buffer its colony biomass accumulation rate across environments by modulating ramet body size through environmentally dependent growth, fission, and catabolism. In 2015, thermal reaction norms for growth and fission behavior were constructed using clonal lines of the sea anemone Diadumene lineata. In 2018, variation in growth patterns under a factorial cross of temperature level and oxygen availability was examined to test the hypothesis that individual ramet size is regulated by oxygen limitation in accordance with optimal size theory. Across a wide range of temperatures, colonies accumulated a similar amount of biomass despite a radical shift from unitary to clonal growth, supporting fission as a mechanism to buffer growth rates over a range of conditions. Individual body size appears to be regulated by the environment with increased temperature and reduced oxygen modifying fission and mass-specific growth patterns, leading to the production of smaller-bodied ramets in warm conditions. However, whether anemones in common garden conditions reduce individual body size through catabolism or fission depends on the region of origin and may relate to differences in seasonal temperature patterns among coastlines, which influence the energetic benefits of fission rate plasticity.

Description: The Osborn Plateau is a large intraplate rise in the eastern part of the Indian Ocean, which has been poorly studied by the geological and geophysical methods. In cruise SO258/1 on the R/V Sonne, new data were collected using Parasound seismic profiling and a multibeam echo-sounder survey. Faults in the sedimentary cover, which extend to the bottom surface, indicate high neotectonic activity in the Osborn Plateau area. It may continue up to the present, as well as in the adjacent segment of the Ninetyeast Ridge, where strong earthquakes have been recorded. Two reflectors in the upper part of the sedimentary cover mark the global lowering of the World Ocean level at the Miocene/Pliocene and Pliocene/Pleistocene boundaries. The reflector in the sediments at the Lower/Upper Pliocene boundary is associated with a change in the regional hydrodynamic regime that occurred at that time in the eastern Indian Ocean. The rocks dredged on Osborn Plateau are identical to some volcanic rocks of the Ninetyeast Ridge, confirming their assumed genetic link, but they are more similar to the basalts of the Kerguelen Plateau. Extremely altered vitroclastic tuffs appear to have been formed as a result of explosive volcanic eruptions of alkali basalts or foidites under subaeral or relatively shallow water conditions and represent the most recent eruptions in the region.

Description: Biodiversity is critical for maintaining and stabilizing ecosystem processes. There is a need for high-resolution biodiversity maps that cover large sea areas in order to address ecological questions related to biodiversity-ecosystem functioning relationships and to provide data for marine environmental protection and management decisions. However, traditional sampling-point-wise field work is not suitable for covering extensive areas in high detail. Spatial predictive modeling using biodiversity data from sampling points and georeferenced environmental data layers covering the whole study area is a potential way to create biodiversity maps for large spatial extents. Random forest (RF), generalized additive models (GAM), and boosted regression trees (BRT) were used in this study to produce benthic (macroinvertebrates, macrophytes) biodiversity maps in the northern Baltic Sea. Environmental raster layers (wave exposure, salinity, temperature, etc.) were used as independent variables in the models to predict the spatial distribution of species richness. A validation dataset containing data that was not included in model calibration was used to compare the prediction accuracy of the models. Each model was also evaluated visually to check for possible modeling artifacts that are not revealed by mathematical validation. All three models proved to have high predictive ability. RF and BRT predictions had higher correlations with validation data and lower mean absolute error than those of GAM. Both mathematically and visually, the predictions by RF and BRT were very similar. Depth and seabed sediments were the most influential abiotic variables in predicting the spatial patterns of biodiversity.

Description: A long-standing difficulty of climate models is to capture the annual cycle (AC) of eastern equatorial Pacific (EEP) sea surface temperature (SST). In this study, we first examine the EEP SST AC in a set of integrations of the coupled Kiel Climate Model, in which only atmosphere model resolution differs. When employing coarse horizontal and vertical atmospheric resolution, significant biases in the EEP SST AC are observed. These are reflected in an erroneous timing of the cold tongue’s onset and termination as well as in an underestimation of the boreal spring warming amplitude. A large portion of these biases are linked to a wrong simulation of zonal surface winds, which can be traced back to precipitation biases on both sides of the equator and an erroneous low-level atmospheric circulation over land. Part of the SST biases also is related to shortwave radiation biases related to cloud cover biases. Both wind and cloud cover biases are inherent to the atmospheric component, as shown by companion uncoupled atmosphere model integrations forced by observed SSTs. Enhancing atmosphere model resolution, horizontal and vertical, markedly reduces zonal wind and cloud cover biases in coupled as well as uncoupled mode and generally improves simulation of the EEP SST AC. Enhanced atmospheric resolution reduces convection biases and improves simulation of surface winds over land. Analysis of a subset of models from the Coupled Model Intercomparison Project phase 5 (CMIP5) reveals that in these models, very similar mechanisms are at work in driving EEP SST AC biases.

Description: Methane gas hydrates have increasingly become a topic of interest because of their potential as a future energy resource. There are significant economical and environmental risks associated with extraction from hydrate reservoirs, so a variety of multiphysics models have been developed to analyze prospective risks and benefits. These models generally have a large number of empirical parameters which are not known a priori. Traditional optimization-based parameter estimation frameworks may be ill-posed or computationally prohibitive. Bayesian inference methods have increasingly been found effective for estimating parameters in complex geophysical systems. These methods often are not viable in cases of computationally expensive models and high-dimensional parameter spaces. Recently, methods have been developed to effectively reduce the dimension of Bayesian inverse problems by identifying low-dimensional structures that are most informed by data. Active subspaces is one of the most generally applicable methods of performing this dimension reduction. In this paper, Bayesian inference of the parameters of a state-of-the-art mathematical model for methane hydrates based on experimental data from a triaxial compression test with gas hydrate-bearing sand is performed in an efficient way by utilizing active subspaces. Active subspaces are used to identify low-dimensional structure in the parameter space which is exploited by generating a cheap regression-based surrogate model and implementing a modified Markov chain Monte Carlo algorithm. Posterior densities having means that match the experimental data are approximated in a computationally efficient way.

Description: A strong warm event occurred in the southeastern tropical Atlantic Ocean off Angola and Namibia in January and February 2016 with sea surface temperature anomalies reaching 3 °C. In contrast to classical Benguela Niño events, the analysis of various direct observations indicates that the warming was not predominantly forced by an equatorial Kelvin wave exciting a coastally trapped wave but instead resulted from a combination of local processes that are related to (1) a weakening of the alongshore, i.e. mainly southerly, winds and (2) enhanced freshwater input through local precipitation and river discharge. Consistent with the weakened winds, we find a reduction in latent heat loss from the ocean and a poleward surface current anomaly. The surface freshening, which is detected in satellite observations of sea surface salinity, caused a very shallow mixed layer and enhanced upper ocean stratification. This is supported by the analysis of the velocity structure of the Angola Current at 11°S, which shows that at the time of the event subsurface velocities were directed northward while surface velocities were directed southward. The shallow layer of warm and fresh surface water was thus advected poleward by the surface current. In addition, a reduction of the local upwelling and the formation of a barrier layer that inhibits the entrainment of cool subsurface waters into the surface mixed layer might have contributed to the warm surface anomaly. The sudden termination of the warm event was accompanied by a re-intensification of southerly winds in March

Description: Almost all the inorganic carbon on Earth is converted into biomass via the Calvin–Benson–Bassham (CBB) cycle. Here, the central carboxylation reaction is catalyzed by ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), which can be found in numerous primary producers including plants, algae, cyanobacteria, and many autotrophic bacteria. Although RubisCO possesses a crucial role in global biomass production, it is not a perfect catalyst. Therefore, research interest persists on accessing the full potential of yet unexplored RubisCOs. We recently developed an activity-based screen suited to seek active recombinant RubisCOs from the environment—independent of the native host’s culturability. Here, we applied this screen to twenty pre-selected genomic fosmid clones from six cultured proteobacteria to demonstrate that a broad range of phylogenetically distinct RubisCOs can be targeted. We then screened 12,500 metagenomic fosmid clones from six distinct hydrothermal vents and identified forty active RubisCOs. Additional sequence-based screening uncovered eight further RubisCOs, which could then also be detected by a modified version of the screen. Seven were active form III RubisCOs from yet uncultured Archaea. This indicates the potential of the activity-based screen to detect RubisCO enzymes even from organisms that would not be expected to be targeted.

Description: Fluctuations in abundance of dominant species can cause competitive release of resources with consequences on community structure and functioning. In the present study, changes in the intertidal macroinfauna community of an exposed sandy beach were evaluated during two contrasting periods characterized by low and high densities of the yellow clam Amarilladesma mactroides. The increase in clam abundance and biomass was associated with a significant decrease in abundance of the rest of the community. In particular, a decline was observed for the pea crab Austinixa patagoniensis, a commensal species that lives in the burrows of the shrimp Sergio mirim. Our study demonstrates that fluctuations in clam abundance lead to long-term changes in community structure, suggesting the presence of competitive interactions. The environmental stability over the two periods strengthens the hypothesis that the competition between species is crucial for shaping the ecological community. Stable isotope analysis allows discarding trophic competition as mechanism of exclusion. Image maps reveal complementary distribution of species, showing the relevance of the spatial competition, which is mediated by changes in abundance of a third species. Indeed, high densities of A. mactroides reduce the available area for the establishment of the S. mirim burrows, limiting the foraging behavior of its commensal, the pea crab. Such an interaction drives density-dependent exclusion of the pea crab from the intertidal zone following the establishment of the yellow clam population. This study illustrates that spatial competition triggered by the increase of a bed-forming species can have community-wide consequences in exposed sandy beaches

Description: The NW-SE striking volcanic front in Nicaragua is dissected into a western and an eastern segment separated by 20 km of N-S offset. The Chiltepe volcanic complex lies at the eastern end of the western segment and at the northern tip of the Nejapa-Miraflores tectonic and volcanic lineament that traces the arc offset. The Chiltepe peninsula attained its present shape and composition during highly explosive and effusive volcanic activity through the Late Pleistocene and Holocene, which formed the Chiltepe Formation (CF) and culminated in the 1.9 ka plinian eruption of the Chiltepe tephra. The previous evolution of this volcanic system is recorded in the volcaniclastic Mateare Formation (MF) exposed west (downwind) of the peninsula and separated from the CF by a large regional erosional unconformity. We divide the MF into the lower MF-1 member (22 volcaniclastic units) and the upper MF-2 member (17 volcaniclastic units), which are separated by a major erosional unconformity. The MF-1 was formed by variably evolved (basalt to dacite) magmas from a mantle source that was moderately metasomatized by fluids derived from subducted sediments. These high-Al moderately hydrous magmas fractionated in a tholeiitic fashion, with early plagioclase but delayed magnetite fractionation (initial Fe-Ti enrichments). Apart from the variable degree of differentiation, magmatic conditions during MF-1 remained fairly constant. While MF-1 contains several erosional unconformities suggesting tectonic activity, MF-2 is conformably stratified and the tholeiitic magmas persisted during this time. However, during MF-2, Al-poor tholeiitic compositions gradually replaced the Al-rich of MF-1 without significant changes in metasomatism or degree of melting at their mantle sources. At the same time, a different mantle source was tapped that was richer in the sediment components, and which produced more hydrous magmas that differentiated in a calc-alkaline fashion with early fractionation of both plagioclase and magnetite. Hence, two mantle source compositions were active during MF-2. The erosional interval between MF and CF, associated with strike-slip motion at the Mateare Fault, correlates with initiation of Nejapa-Miraflores volcanism. We postulate that extension along the Najapa-Miraflores fault system facilitated rapid ascent of mafic magmas from a mantle source laterally away from the arc axis that was less metasomatized than sources directly below the arc. On the Chiltepe peninsula, the Nejapa-Miraflores and Chiltepe magma systems interacted to form tholeiitic, less hydrous types of magmas (andesite to dacite) that erupted intermittently with the dominant calc-alkaline hydrous dacites. While associations of tholeiitic and calc-alkaline magmas at other subduction zones have often been attributed to variable intracrustal processes, we here argue for changes in the mantle source, particularly hydration by slab-derived fluids, as the main control on subsequent differentiation behavior. We further attribute the long-term changes in mantle source conditions through MF and CF, possibly over about 1 My, to result from temporal heterogeneity caused by mantle wedge solid flow and possibly variable fluid flow from the slab.

Description: The increasing use of rare earth elements (REEs) in diverse technological applications has augmented the demand and exploitation of these worldwide, leading to a higher input of REEs + Yttrium (Y) in the marine environment. The present study investigated the ecotoxicity of Lanthanum (La) and Y to Mytilus galloprovincialis developing embryos and juveniles. This was achieved by quantifying the embryogenesis success after 48 h, and survival of juveniles after 96 h of exposure to different concentrations of La and Y. Results show that both La and Y are more toxic to developing embryos and larvae than to juveniles of M. galloprovincialis. Predicted no-effect concentration (PNEC) values were also derived for the embryo development as a preliminary approach to assess the environmental risk for these compounds to marine organisms. Results revealed that La is more toxic than Y. The high sensitivity of the early developmental stages to these compounds highlight the relevance of including these stages when evaluating the toxicity of chemicals where little information is available. Although older life stages may be more tolerant to toxicants, the population survival will be compromised if new recruits are not viable, with implications to the whole ecosystem health and functioning of the impacted area. Information on the ecotoxicity of chemicals with expanded technological use and that may be released during deep-sea mining activities is urgent in order to help estimate environmental impacts.

Description: Abyssal plains of the Clarion Clipperton Fracture Zone (CCZ) in the NE Pacific Ocean probably harbour one of the world’s most diverse ecosystems. Gaining a basic understanding of the mechanisms underlying the evolution and persistence of CCZ biodiversity in terms of biogeography and connectivity has both scientific merit and informs the development of policy related to potential future deep-sea mining of mineral resources at an early stage in the process. Existing archives of polychaetes and isopods were sorted using a combined molecular and morphological approach, which uses nucleotide sequences (cytochrome c oxidase subunit I (COI)) and morphological information to identify appropriate sample sets for further investigations. Basic patterns of genetic diversity, divergence and demographic history of five polychaete and five isopod species were investigated. Polychaete populations were found to be genetically diverse. Pronounced long- and short-distance dispersal produces large populations that are continuously distributed over large geographic scales. Although analyses of isopod species suggest the same, spatial genetic structuring of populations do imply weak barriers to gene flow. Mining-related, large-scale habitat destruction has the potential to impact the continuity of both isopod and polychaete populations as well as their long-term dispersal patterns, as ecosystem recovery after major impacts is predicted to occur slowly at evolutionary time scales.

Description: The Earth will exhibit continued global surface warming in response to a sustained increase of atmospheric carbon dioxide (CO2) levels. Massive meltwater input from the Antarctic ice sheet into the Southern Ocean could be one consequence of this warming. Here we investigate the impacts which this meltwater input may have on Earth’s surface climate and ocean circulation in a warming world. To this end a set of ensemble experiments has been conducted with a global climate model forced by increasing atmospheric CO2-concentration and an idealized Antarctic meltwater input to the Southern Ocean with varying amplitude and spatial pattern. As long as the atmospheric CO2-concentration stays moderate, i.e. below approximately twice the preindustrial concentration, and if a strong meltwater forcing of either 0.05 or 0.1 Sv is applied, enhanced Antarctic sea–ice cover and surface air temperature cooling over most parts of the Southern Ocean is observed. When the atmospheric CO2-concentration becomes larger than twice the preindustrial concentration, the meltwater only plays a minor role. The Antarctic meltwater drives significant slowing of the Southern Ocean meridional overturning circulation (MOC). Again, the meltwater influence only is detectable as long as the CO2-forcing is moderate. Much larger MOC changes develop in response to highly elevated atmospheric CO2-levels independent of whether or not a meltwater forcing is applied. The response of the Antarctic circumpolar current (ACC) is nonlinear. Substantial and persistent ACC slowing is simulated when solely the meltwater forcing of 0.1 Sv is applied, which is due to the halt of Weddell Sea deep convection and subsequent collapse of the Southern Ocean MOC. When the increasing atmospheric CO2-concentration additionally drives the model the ACC partly recovers in the long run. The partial recovery is due to strengthening westerly wind stress over the Southern Ocean, which intensifies the Ekman Cell. This study suggests that Southern Hemisphere climate projections for the twenty-first century could benefit from incorporating interactive Antarctic ice sheet.

Description: An interactive (multi-access) global identification key (OncIdent) has been developed for the pelagic marine microcopepod family Oncaeidae and made accessible online. Details of the general approach and development of the key are given in Bottger-Schnack and Schnack (J Nat Hist 49:2727-2741, 2015). After beta-testing, new additions include illustrations for all species and feature attributes considered, plus a textual summary of each species' feature states in the key. Additional taxonomic notes are given where required, highlighting morphological or molecular genetic peculiarities or problems, with links to large data bases leading directly to more comprehensive information about each species. The present paper briefly reviews the taxonomic background for key construction, summarizes the opportunities and limitations of the current online version OncIdent2.0, and provides guidance for its practical use.

Description: Recent work has shown that glaciers are a globally significant source of the micronutrient Fe to the ocean. Polar regions are particularly susceptible to climate change and have been subject to pronounced warming in the past few decades. In response to this warming, the volume of glacial meltwater runoff from Greenland has increased. This meltwater has a relatively high particulate and dissolved Fe content. Seasonal Fe limitation of marine ecosystems has been found in parts of the North Atlantic, so it has been proposed that increasing fluxes of Fe rich meltwater from Greenland to the North Atlantic could alleviate this Fe limitation and thereby increase marine primary production. However, here we use a synthesis of biogeochemical and physical oceanography studies to suggest that the physical circulation around Greenland does not favour direct export of dissolved or particulate Fe from inshore to offshore waters. The Fe budget in surface waters of the North Atlantic may therefore be insensitive to increasing meltwater fluxes from Greenland.

Description: While the geometries of diatom frustules have been investigated in detail, the processes leading to their formation—morphogenesis and biomineralization—are not well understood. The study of organic templates, which are suspected to be important for biosilicification of diatoms, have been mainly investigated on the basis of diverse demineralization techniques. In contrast to naturally occurring dissolution of diatom cell walls in natural habitats, all experiments in vitro were based on chemical reagents including HF- or alkali-based techniques with addition of some additives as presented in this chapter. Mostly, the amino acids (serine, threonine, hydrohyproline) diverse proteinaceous materials (frustulins, pleuralins, silaffins, silacidins, circulins) as well as polyamines have been proposed to regulate biosilicification in vivo in diatoms. In this chapter, we review the biochemical pathways and potential functions of these chemical compounds and their roles in the biomineralization process. In addition, we demonstrate the presence of chitin and discuss its potential as scaffolding as well as a template material in siliceous cell walls of diatoms. The current findings show that a complex network of different organic components is responsible for the biomineralization of diatoms. Since both the organic network and the precipitated silica are integrated in the material which forms the diatom frustule, the material properties must differ from that of pure silica. As the material properties are a crucial factor for the defensive performance of the frustule and thus their survival, it is likely that organic templates for silicification play a role both for the development process and for the improvement of the material properties of the finished shells.

Description: Pteropods are important organisms in high-latitude ecosystems, and they are expected to severely suffer from climate change in the near future. In this study, sedimentation patterns of two pteropod species, the polar Limacina helicina and the subarctic boreal L. retroversa, are presented. Time series data received by moored sediment traps at the Long-Term Ecological Research (LTER) Observatory HAUSGARTEN in eastern Fram Strait were analyzed during the years 2008 to 2012. Results were derived from four different deployment depths (~200, 1,250, 2,400, and 2,550 m) at two different sites (79°N 04°20′E; 79°43′N 04°30′E). A species-specific sedimentation pattern was present at all depths and at both sites showing maximal flux rates during September/October for L. helicina and in November/December for L. retroversa. The polar L. helicina was outnumbered by L. retroversa (55–99 %) at both positions and at all depths supporting the recently observed trend toward the dominance of the subarctic boreal species. The largest decrease in pteropod abundance occurred within the mesopelagic zone (~200–1,250 m), indicating loss via microbial degradation and grazing. Pteropod carbonate (aragonite) amounted up to ~75 % of the total carbonate flux at 200 m and 2–13 % of the aragonite found in the shallow traps arrived at the deep sediment traps (~160 m above the seafloor), revealing the significance of pteropods in carbonate export at Fram Strait. Our results emphasize the relevance and the need for continuation of long-term studies to detect and trace changes in pteropod abundances and community composition and thus in the vertical transport of aragonite.

Description: Radiolaria are unicellular holoplanktonic protozoa with siliceous or strontium sulfate skeletons. Mainly studied by micropaleontologists because of their excellent fossil record, they are also key members of planktonic communities and play important roles in various oceanic ecosystems. This chapter presents an overview of the current knowledge on living Radiolaria (orders Acantharia, Collodaria, Nassellaria, Spumellaria and Taxopodia). Besides general considerations on Radiolaria as a whole, it focuses on the taxonomy, biology, and ecology of each radiolarian order. Finally this chapter provides insights on research perspectives to improve our knowledge of living radiolarians and their ecological role in marine ecosystems.

Description: Integrated multi-trophic aquaculture (IMTA) is being explored on both economic and environmental grounds in many traditional aquaculture regions. To test a variety of suitable macroalgae species and management scenarios, a numerical model is developed to quantify the remediation of dissolved nutrients and production of macroalgae near a nutrient source. Differences in the morphological, physiological, and economic characteristics of different macroalgae species can provide flexibility when considering the cost and benefit of farming macroalgae. Results show that of the three species studied, Macrocystis pyrifera removed 75 % of dissolved inorganic nitrogen (DIN) input from a point source, while Porphyra umbilicalis and Ulva lactuca removed 5 %. Both M. pyrifera and P. umbilicalis have reduced bioremediation capacity at increasing flow rates. U. lactuca showed increased bioremediation potential as flow rate increased from low to moderate flows. Increasing the optical depth increased the bioremediation potential of M. pyrifera for moderate values of the light attenuation coefficient, whereas bioremediation was unaffected by optical depth for both U. lactuca and P. umbilicalis. Harvesting increased bioremediation capacity of all species by up to 25-fold dependent on the establishment phase and harvesting frequency. We conclude that the choice of macroalgae species greatly affects the success of IMTA and that both harvesting and farm arrangements can be used to greatly optimize bioremediation.

Description: Hydrothermal vents on mid-oceanic ridges are patchily distributed and host many taxa endemic to deep-sea chemosynthetic environments, whose dispersal may be constrained by geographical barriers. The aim of this study was to investigate the connectivity of three populations of the ‘scaly-foot gastropod’ (Chrysomallon squamiferum Chen et al., 2015), a species endemic to hydrothermal vents in the Indian Ocean, amongst two vent fields on the Central Indian Ridge (CIR) and Longqi field, the first sampled vent field on the Southwest Indian Ridge (SWIR). Connectivity and population structure across the two mid-oceanic ridges were investigated using a 489-bp fragment of the cytochrome oxidase c subunit I (COI) gene. Phylogeographical approaches used include measures of genetic differentiation (FST), reconstruction of parsimony haplotype network, mismatch analyses and neutrality tests. Relative migrants per generation were estimated between the fields. Significant differentiation (FST = 0.28–0.29, P 〈 0.001) was revealed between the vent field in SWIR and the two in CIR. Signatures were detected indicating recent bottleneck events followed by demographic expansion in all populations. Estimates of relative number of migrants were relatively low between the SWIR and CIR, compared with values between the CIR vent fields. The present study is the first to investigate connectivity between hydrothermal vents across two mid-ocean ridges in the Indian Ocean. The phylogeography revealed for C. squamiferum indicates low connectivity between SWIR and CIR vent populations, with implications for the future management of environmental impacts for seafloor mining at hydrothermal vents in the region, as proposed for Longqi.

Description: Mature organisms often have to trade reproductive opportunities against the need to survive, especially in species with exaggerated, sexually selected traits. Life history theory predicts that old males with low residual reproductive value (RRV) would accept greater risk for current reproduction than their younger counterparts. Accordingly, we tested the prediction that, under predation risk, old males of the rock shrimp Rhynchocinetes typus pair with females faster and for a longer time than young males do. We exposed young and old dominant males (in the final ontogenetic stage, called “robustus”) to a female in the absence and presence of a predator. As predicted, older robustus males modified their mating behavior when exposed to a predator. However, in contrast to the prediction, they delayed female seizure under predation risk, possibly to carefully assess the actual threat before initiating female guarding. Once they had established the mate-guarding position, old robustus males did not interrupt it until the end of female spawning and, in the presence of predators, even guarded the female significantly longer than in predator-free treatments. In contrast, younger robustus males did not delay female seizure but abandoned the female repeatedly when a predator was present, suggesting that they perceived and responded to the predation risk. Our results suggest that older robustus males have the experience to assess threats before engaging in risky behaviors that bolster their reproductive success. Although consistent with the theory that low RRV individuals should accept greater reproductive risk, we suggest that old individuals do not recklessly engage in risky behaviors but rather cautiously evaluate the threats before investing in a potentially terminal reproductive event.

Description: The serine/threonine kinase glycogen synthase kinase-3 (GSK-3) is involved in a broad range of cellular processes including cell proliferation, apoptosis and inflammation. It is now also increasingly acknowledged as having a role to play in cognitive-related processes such as neurogenesis, synaptic plasticity and neural cell survival. Cognitive impairment represents a major debilitating feature of many neurodegenerative and psychiatric disorders, including Alzheimer's disease, mood disorders, schizophrenia and fragile X syndrome, as well as being a result of traumatic brain injury or cranial irradiation. Accordingly, GSK-3 has been identified as an important therapeutic target for cognitive impairment, and recent preclinical studies have yielded important evidence demonstrating that GSK-3 inhibitors may be useful therapeutic interventions for restoring cognitive function in some of these brain disorders. The current review summarises the role of GSK-3 as a regulator of cognitive-dependent functions, examines current preclinical and clinical evidence of the potential of GSK-3 inhibitors as therapeutic agents for cognitive impairments in neuropsychiatric disorders, and offers some insight into the current obstacles that are impeding the clinical use of selective GSK-3 inhibitors in the treatment of cognitive impairment.

Description: The European water framework directive and the marine strategy framework directive have the objective to establish at least ‘good’ ecological status in all European waters by 2015. Therefore a classification system has to be established in each European country, in order to assess their water bodies. For the German coastal waters of the Baltic Sea, a classification system for phytoplankton based on the abundance of Cyanophyceae and Chlorophyceae was already presented. This system has been successfully adapted in regions with low salinity levels (〈10 PSU). With this study, we present the results trying to develop a classification system for our German region of the Baltic Sea characterized by higher salinity (〉15 PSU). All present taxonomic groups, most common species and functional groups were tested. It could be shown that all tested correlations to nitrogen concentration as eutrophication descriptor are relatively week. Nevertheless, the biovolume of Cryptophyceae was found to be the most reliable phytoplankton composition indicator, which could serve as future assessment criterion. Furthermore, as proposed by some experts, the use of maximal dissolved winter nitrogen concentration as eutrophication descriptor might be an advantage over using the total nitrogen concentrations in summer.

Description: A comparison of micropaleontological data on the distribution of the Cycladophora davisiana radiolarian species in the surface sediment layer and the Late Quaternary sediments from the Subarctic Pacific and Far East marginal seas allowed conclusions concerning the possible conditions and occurrence of intermediate waters during the last glacial maximum. We used the modern data on the C. davisiana species, which is a micropaleontological indicator of the cold oxygen-rich upper intermediate water mass, which is now forming only in the Sea of Okhotsk. The high amount of C. davisiana in sediments of the last glacial maximum may point to the possible formation and expansion of the ventilated intermediate water in the most part of the Subarctic paleo-Pacific: the Bering Sea, the Sea of Okhotsk, within the NW Gyre, and in the Gulf of Alaska.

Description: Coral reefs are the most abundant shallow water ecosystems in the Red Sea, harboring a high species diversity and habitat complexity over large environmental gradients. At the same time the semi-enclosed ocean basin and its partly extreme environmental conditions may promote species evolution being distinct from Indo-Pacific coral reefs. Extreme conditions are found in the southern Red Sea, where temperatures reach up to 33 °C in summer and where nutrient input is high. Mechanisms of organism adjustment to these conditions are of particular interest in the light of climate change research. Towards the north, conditions become more ‘coral-promoting’ finally reaching temperatures between 21–27 °C (winter-summer) and clear waters at the northern end of the Red Sea (Gulf of Aqaba). In this chapter, we summarize the current knowledge about the biology of shallow water, symbiotic, reef-building corals of the Red Sea. We start with an overview on the environmental conditions of the Red Sea, the history of coral reef research in this region and a general introduction into coral biology, before we describe the ecophysiology of Red Sea corals. Coral ecophysiology is presented in the context of varying environmental conditions over depth (e.g., light), between seasons, and over latitudes (e.g., light, temperature, nutrients). Mechanisms and patterns of coral reproduction are discussed in the context of seasonal and latitudinal environmental changes. Finally, we briefly describe anthropogenic influences on Red Sea coral reefs. Acclimatization mechanisms of corals to changing conditions over a depth gradient (mainly light reduction) have been well studied in the Gulf of Aqaba and include the following metabolic adjustments with depth: (i) an upregulation of light-harvesting pigments (chlorophyll a) and a downregulation of photo-protective pigments (xanthophyll), (ii) an increase of heterotrophy, and (iii) a decrease of metabolic activity (e.g., calcification and growth). In addition, a change in the symbiont composition (Symbiodinium clade and/or type) over depth was observed in some coral species. Seasonal environmental changes (mainly light availability, temperature, nutrients) lead to various metabolic responses of the corals, including (i) changes in zooxanthellae pigmentation and density and (ii) changes in the metabolic activity. In particular, changes in calcification and growth rates can be observed with lowest rates during low temperatures in winter. Interestingly, however, this reverses in the southern Red Sea, where calcification rates are higher in winter than in summer. This kind of latitudinal shift is also evident in the timing of reproduction, which occurs earlier in the year (January–March) in the south compared to the north (March–August). This indicates that growth and reproduction are strongly linked to temperature, following a single temperature optimum, which occurs at different times throughout the year from north to south. Furthermore, this hints towards a high phenotypic plasticity (acclimatization) rather than local genetic adaptation of the investigated coral species. A clear shift in the genetic population structure from north to south in another coral species, however, indicates local adaption. Adjusting mechanisms need to be further understood in order to provide indication for predicted climate change effects.

Description: Sub-micron marine aerosol particles (PM1) were collected over the period 22 June–21 July 2011 during the RV MARIA S. MERIAN cruise MSM 18/3, which travelled from the Cape Verdean island of São Vicente to Gabon, in the process crossing the tropical Atlantic Ocean with its equatorial upwelling regime. According to air mass origin and the chemical composition of the sampled aerosol particles, three main regimes could be established. Aerosol particles in the first part of the cruise were mainly of marine origin (Region I). In the second part of the cruise, marine influences mixed with increasing influence from biomass burning (Region II). In the final part of the cruise, which approached the African mainland, the biomass burning influence became dominant (Region III). Generally, aerosol particles were dominated by sulfate (caverage = 2.0 μg m−3) and ammonium ions (caverage = 0.7 μg m−3), which were well-correlated and increased slightly over the duration of the cruise. High concentrations of water-insoluble organic carbon (WISOC; caverage = 0.4 μg m−3) were found, most likely as a result of the high oceanic productivity in this region. Water-soluble organic carbon (WSOC) concentrations increased from 0.26 μg m−3 in Region I to 2.3 μg m−3 in Region III, most likely as a result of biomass burning influences. The major organic aerosol constituents were oxalic acid, methanesulfonic acid (MSA), and aliphatic amines. MSA concentrations were quite constant during the cruise (caverage = 42 ng m−3). Aliphatic amines were most abundant in Region I, with concentrations of ~ 20 ng m−3. Oxalic acid showed the opposite trend, with average concentrations of 12 ng m−3 in Region I and 158 ng m−3 in Region III. The α-dicarbonyl compounds glyoxal and methylglyoxal were detected in the aerosol particles in the low ng m−3 range and were closely correlated with oxalic acid. MSA and aliphatic amines arise from biogenic marine sources, whereas oxalic acid and the α-dicarbonyl compounds were attributed to biomass burning. Concentrations of n-alkanes increased from 0.8 to 4.7 ng m−3 over the duration of the cruise. PAHs and hopanes were abundant only in Region III (caverage of PAHs = 0.13 ng m−3; caverage of hopanes = 0.19 ng m−3). Levoglucosan was identified in several samples obtained in Region III, with caverage = 1.9 ng m−3, which points to (aged) biomass burning influences. The organic compounds quantified in this study could explain 8.3 % of WSOC in Regions I, where aliphatic amines and MSA dominated, 3.7 % of WSOC in Region II and 2.5 % of WSOC in Region III, where oxalic acid dominated.

Description: An ocean circulation model is run using two different idealized equatorial basin configurations under steady wind forcing. Both model versions produce bands of vertically alternating zonal flow at depth, similar to observed Equatorial Deep Jets (EDJs) and with a time scale corresponding to that of the gravest equatorial basin mode for the dominant baroclinic vertical normal mode. Both model runs show evidence for enhanced variability in the surface signature of the North Equatorial Counter Current (NECC) with the same time scale. We also find the same link between the observed NECC and the EDJs in the Atlantic by comparing the signature of the EDJ in moored zonal velocity data at 23° W on the equator with the signature of the NECC in geostrophic velocities from altimeter data. We argue that the presence of a peak in variability in the NECC associated with the EDJ basin mode period is evidence that the influenceatthis time scale is upward, from the EDJ to the NECC

Description: Ocean acidification studies in the past decade have greatly improved our knowledge of how calcifying organisms respond to increased surface ocean CO2 levels. It has become evident that, for many organisms, nutrient availability is an important factor that influences their physiological responses and competitive interactions with other species. Therefore, we tested how simulated ocean acidification and eutrophication (nitrate and phosphate enrichment) interact to affect the physiology and ecology of a calcifying chlorophyte macroalga (Halimeda opuntia (L.) J.V. Lamouroux) and its common noncalcifying epiphyte (Dictyota sp.) in a 4-week fully crossed multifactorial experiment. Inorganic nutrient enrichment (+NP) had a strong influence on all responses measured with the exception of net calcification. Elevated CO2 alone significantly decreased electron transport rates of the photosynthetic apparatus and resulted in phosphorus limitation in both species, but had no effect on oxygen production or respiration. The combination of CO2 and +NP significantly increased electron transport rates in both species. While +NP alone stimulated H. opuntia growth rates, Dictyota growth was significantly stimulated by nutrient enrichment only at elevated CO2, which led to the highest biomass ratios of Dictyota to Halimeda. Our results suggest that inorganic nutrient enrichment alone stimulates several aspects of H. opuntia physiology, but nutrient enrichment at a CO2 concentration predicted for the end of the century benefits Dictyota sp. and hinders its calcifying basibiont H. opuntia.

Description: Metals constitute an important group of abiotic stressors that elicit stress responses in marine algae that include the production of reactive oxygen species (ROS). Silver (Ag) is a highly toxic metal to organisms but despite this there are relatively few studies on how it affects marine macroalgae (seaweeds). In a landmark study published in 1977 the first information was provided on the accumulation of Ag in Fucus spp. (Phaeophyceae) from the Looe estuary, located in south-west England, an area with a long history of mining activity. In the present study, the estuary has been re-visited and the patterns of Ag accumulation in two Fucus spp. and sediment re-examined after 35 years. We conclude that Ag concentrations in sediment and macroalgae from specific sites within the catchment remain high, but more generally sediment concentrations have declined by approximately 65 % and the dissolved, bioavailable fraction by 24 % over this period. In addition, from laboratory studies we provide data on the speciation and toxic effects of Ag under different salinity regimes in the euryhaline brown seaweed, Fucus ceranoides. From these exposure experiments, it was found that with increasing Ag concentrations growth was inhibited and lipid peroxidation associated with ROS production increased. The magnitude of the toxic effects was greater at a salinity of 10 than 28 psu which reflects the greater bioavailability of the toxic species of Ag (Ag+ and AgCl0) at reduced salinities. These findings emphasise the importance of investigating the effects of metal pollution in conjunction with other, natural, environmental stressors such as salinity.

Description: Aurelia spp. is a cosmopolite scyphozoan species and likely the most studied jellyfish in the world. Its pelagic–benthic life cycle is complex, and the benthic asexual reproducing stage (polyp) is acknowledged fundamentally in bloom onset. Despite this, field investigations remain scarce and are mainly restrained to the western Pacific Ocean. Thau lagoon (43°23′59.10″ N 3°36′37.15″ E), a semi-enclosed system that harbours a resident population of Aurelia sp., is in essence a natural laboratory that offers an ideal framework to investigate the life cycle of the species. We here used a non-destructive approach consisting on a field survey over the entire lagoon (ca. 7 ha) and several substrate types by free diving to examine the distribution and habitat use of Aurelia sp. benthic population. We show that polyps were largely distributed over the entire lagoon, settled mainly on artificial hard substrates, thereby stressing the promoting role of anthropogenic perturbations in coastal areas, i.e. habitat modification, for jellyfish proliferations. Therefore, our study suggest a potential increase in Aurelia sp. benthic populations as an outcome of mounting coastal constructions in the near future; the consequences of which ultimately might promote an increase in jellyfish outbreaks.

Description: Estuarine systems play a critical role as nursery areas for some fish species. Nursery function, nevertheless, is likely to vary among estuaries, mostly due to differences in habitat quality. High quality nursery habitats are those in which growth and survival of early stages of fish are enhanced. The nutritional condition of larval fishes has vital implications for their mortality and growth, and thereby their recruitment. This study aimed to compare the nutritional condition of Gichristella aestuaria larvae, using individual RNA-DNA ratios and growth rates in the upper reaches of six estuaries in South Africa to find the environmental factors that better determine the nutritional condition of fish larvae. Physico-chemical factors as well as calorific value of zooplankton were used to correlate to fish body condition. Results showed that the larvae of G. aestuaria from the freshwater rich Gamtoos and the Sundays estuaries were in better nutritional condition than the larvae from other estuaries, while larvae from the Swartkops Estuary, a highly eutrophic system, presented the worst nutritional condition of all studied larvae. Salinity and the abundance of zooplankton were the major factors determining the nutritional condition of G. aestuaria larvae in these warm temperate estuaries. In addition, our results suggest that the match-mismatch hypothesis might also be important in estuarine systems. This study represents one of the few studies worldwide that applied a multispecies growth model for fish larvae in warm temperate estuaries

Description: Many exploited fish species are threatened with collapse and the European eel is no exception. Its abundance has declined dramatically and various reasons account for this, among them the introduction of the invasive swim bladder nematode Anguillicola crassus. For developing an adequate immune response against this parasite, variation at the genes of the major histocompatibility complex (MHC), a key component of the adaptive immune system, might be essential and assessing their diversity might provide critical information for improving conservation strategies. Here, we characterized the MHC class II of the European eel. We provide evidence for relatively high diversity at both MHC IIA and MHC IIB, which contrasts with findings for other endangered species. Furthermore, both genes show signs of site-specific positive selection. The absence of overall positive selection at MHC IIB might, however, suggests that demographic shifts have negatively impacted that gene, thereby possibly reducing the adaptive potential of the European eel.

Description: Stable carbon isotopes of dissolved inorganic carbon (δ13CDIC) in the ocean are generally not well understood as they are governed by a complex interplay of biological processes and air–sea exchange. In the Arctic Ocean, δ13CDIC values are prone to change in the near future with rapidly changing climate conditions. This study provides a baseline to assess the δ13CDIC of the Arctic Ocean with a focus on upper to intermediate waters (to ~500 m). Measured δ13CDIC values in the Arctic Ocean range from ~−0.6 to +2.2 ‰. In the Eurasian Basin, the δ13CDIC values lie between ~1 and 1.5 ‰ and exhibit little variation within the upper layers. In the Canada Basin, δ13CDIC values reach 2 ‰ in the surface layer, with lowest values of ~−0.6 ‰ found at ~200 m water depth. At greater depth, δ13CDIC values range from ~1 to 1.5 ‰ within both basins. In the Canada Basin, nutrient levels are higher than in the Eurasian Basin and associated variations in δ13CDIC are clearly related to biological processes. However, low δ13CDIC values in the Canada Basin are also strongly influenced by non-equilibrium air–sea exchange processes. The different δ13CDIC patterns between the Canada Basin and the Eurasian Basin appear to be linked to differences in transport processes within the Arctic Ocean halocline. The upper layers in the Canada basins have direct contributions of waters from the Laptev, East Siberian and Chukchi shelves, which contain elevated fractions of river waters and sea-ice related brines, whereas their counterparts, in the Eurasian Basin, are mostly formed by halocline waters from the Barents and Kara seas. River waters have low δ13CDIC of ~−8 ‰ on average, but in the Arctic basins this signal is mostly lost and δ13CDIC values show only a weak correlation to river water fractions contained in the water mass. No relation between δ13CDIC and sea-ice related brine contribution is apparent.

Description: Definition Ocean acidification refers to the process of increasing seawater acidity by dissolving additional carbon dioxide (CO2) from the atmosphere. As CO2 dissolves in seawater, it forms carbonic acid (H2CO3), which readily dissociates into bicarbonate (HCO3−) and hydrogen (H+) ions. The hydrogen ion concentration determines the acidity of seawater, expressed by the pH scale. Part of the hydrogen ions released in this process is buffered by the seawater carbonate system by consuming carbonate ions (CO32−) and forming additional bicarbonate. As pH is defined as the negative logarithm of the hydrogen ion concentration, pH decreases as the acidity increases (Fig. 1). Fig. 1 The process of ocean acidification: (1) atmospheric carbon dioxide (CO2) dissolving in seawater; (2) dissolved CO2 reacting with water to form carbonic acid (H2CO3); (3) carbonic acid dissociating to bicarbonate (HCO3−) and hydrogen ion (H+); and (4) hydrogen ion reacting with carbonate (CO3 ... This is an excerpt from the content

Description: The ~16-ka-long record of explosive eruptions from Shiveluch volcano (Kamchatka, NW Pacific) is refined using geochemical fingerprinting of tephra and radiocarbon ages. Volcanic glass from 77 prominent Holocene tephras and four Late Glacial tephra packages was analyzed by electron microprobe. Eruption ages were estimated using 113 radiocarbon dates for proximal tephra sequence. These radiocarbon dates were combined with 76 dates for regional Kamchatka marker tephra layers into a single Bayesian framework taking into account the stratigraphic ordering within and between the sites. As a result, we report ~1,700 high-quality glass analyses from Late Glacial–Holocene Shiveluch eruptions of known ages. These define the magmatic evolution of the volcano and provide a reference for correlations with distal fall deposits. Shiveluch tephras represent two major types of magmas, which have been feeding the volcano during the Late Glacial–Holocene time: Baidarny basaltic andesites and Young Shiveluch andesites. Baidarny tephras erupted mostly during the Late Glacial time (~16–12.8 ka BP) but persisted into the Holocene as subordinate admixture to the prevailing Young Shiveluch andesitic tephras (~12.7 ka BP–present). Baidarny basaltic andesite tephras have trachyandesite and trachydacite (SiO2 〈 71.5 wt%) glasses. The Young Shiveluch andesite tephras have rhyolitic glasses (SiO2 〉 71.5 wt%). Strongly calc-alkaline medium-K characteristics of Shiveluch volcanic glasses along with moderate Cl, CaO and low P2O5 contents permit reliable discrimination of Shiveluch tephras from the majority of other large Holocene tephras of Kamchatka. The Young Shiveluch glasses exhibit wave-like variations in SiO2 contents through time that may reflect alternating periods of high and low frequency/volume of magma supply to deep magma reservoirs beneath the volcano. The compositional variability of Shiveluch glass allows geochemical fingerprinting of individual Shiveluch tephra layers which along with age estimates facilitates their use as a dating tool in paleovolcanological, paleoseismological, paleoenvironmental and archeological studies. Electronic tables accompanying this work offer a tool for statistical correlation of unknown tephras with proximal Shiveluch units taking into account sectors of actual tephra dispersal, eruption size and expected age. Several examples illustrate the effectiveness of the new database. The data are used to assign a few previously enigmatic wide-spread tephras to particular Shiveluch eruptions. Our finding of Shiveluch tephras in sediment cores in the Bering Sea at a distance of ~600 km from the source permits re-assessment of the maximum dispersal distances for Shiveluch tephras and provides links between terrestrial and marine paleoenvironmental records.

Description: Increasing anthropogenic CO2 concentration in the atmosphere is altering sea water carbonate chemistry with unknown biological and ecological consequences. Whereas some reports are beginning to emerge on the effects of ocean acidification (OA) on fish, very little is known about the impact of OA on jellyfish. In particular, the benthic stages of metagenetic species are virtually unstudied in this context despite their obvious importance for bloom dynamics. Hence, we conducted tri-trophic food chain experiments using the algae Rhodomonas salina as the primary producer, the copepod Acartia tonsa as the primary consumer and the benthic life stage of the scyphozoans Cyanea capillata and Chrysaora hysoscella as secondary consumers. Two experiments were conducted examining the effects of different levels of CO2 and food quality (experiment 1) and the effect of food quality and quantity (experiment 2) on the growth and respiration of scyphozoan polyps. Polyp growth and carbon content (µg polyp−1) were not affected by the CO2 treatments, but were significantly negatively affected by P limitation of the food in C. capillata but not in Ch. hysoscella. Growth and carbon content were reduced in low-food treatments, but increased with decreasing P limitation in high- and low-food treatments in C. capillata. Respiration was not significantly influenced by food quality and quantity in C. capillata. We conclude that phosphorus can be a limiting factor affecting the fitness of scyphopolyps and that P-limited food is of poor nutritional quality. Furthermore, OA, at least using realistic end-of-century scenarios, will have no direct effect on the growth of scyphistomae

Description: Current pressures to mine polymetallic sulfide deposits pose threats to the animal communities found at deep-sea hydrothermal vents. Management plans aimed at preserving these unusual communities require knowledge of historical and contemporary forces that shaped the distributions and connectivity of associated species. As most vent research has focused on the eastern Pacific and mid-Atlantic ridge systems less is known about Indo-Pacific vents, where mineral extraction activities are imminent. Deep-sea mussels (Bivalvia: Mytilidae) of the genus Bathymodiolus include the morphotypic species B. septemdierum, B. brevior, B. marisindicus, and B. elongatus which are among the dominant vent taxa in western Pacific back-arc basins and the Central Indian Ridge. To assess their interpopulational relationships, we examined multilocus genotypes based on DNA sequences from four nuclear and four mitochondrial genes, and allozyme variation encoded by eleven genes. Bayesian assignment methods grouped mussels from seven widespread western Pacific localities into a single cluster, whereas the Indian Ocean mussels were clearly divergent. Thus, we designate two regional metapopulations. Notably, contemporary migration rates among all sites appeared to be low despite limited population differentiation, which highlights the necessity of obtaining realistic data on recovery times and fine-scale population structure to develop and manage conservation units effectively. Future studies using population genomic methods to address these issues in a range of species will help to inform management plans aimed at mitigating potential impacts of deep-sea mining in the Indo-Pacific region.

Description: The Atlantic meridional overturning circulation (AMOC) and the subpolar gyre (SPG) are important elements in mechanisms for multidecadal variability in models in the North Atlantic Ocean. In this study, a 2000-year long global ocean model integration forced with the atmospheric patterns associated with a white noise North Atlantic Oscillation (NAO) index is shown to have three distinct timescales of North Atlantic Ocean variability. First, an interannual timescale with variability shorter than 15 years, that can be related to Ekman dynamics. Second, a multidecadal timescale, on the 15- to 65-year range, that is mainly concentrated in the SPG region and is controlled by constructive interference between density anomalies around the gyre and the changing NAO forcing. Finally, the centennial timescales, with variability longer than 65 years, that can be attributed to the ocean being in a series of quasi-equilibrium states. The relationship between the ocean’s response and the NAO index differs for each timescale; the 15-year and shorter timescales are directly related to the NAO of the same year, 15- to 65-year timescales are dependent on the NAO index in the last 25–30 years in a sinusoidal sense while the 65-year and longer timescales relate to a sum of the last 50–80 years of the NAO index.

Description: Extraordinarily strong El Niño events, such as those of 1982/1983 and 1997/1998, cause havoc with weather around the world, adversely influence terrestrial and marine ecosystems in a number of regions and have major socio-economic impacts. Here we show by means of climate model integrations that El Niño events may be boosted by global warming. An important factor causing El Niño intensification is warming of the western Pacific warm pool, which strongly enhances surface zonal wind sensitivity to eastern equatorial Pacific sea surface temperature anomalies. This in conjunction with larger and more zonally asymmetric equatorial Pacific upper ocean heat content supports stronger and longer lasting El Niños. The most intense events, termed Super El Niños, drive extraordinary global teleconnections which are associated with exceptional surface air temperature and rainfall anomalies over many land areas.

Description: The hypothesis that the tropical oceans lead the global warming at the Termination I and II by ~2,000 to ~3,000 years (Visser et al. 2003) whereas melting of the northern continental ice masses is lacking behind challenges the Milankovitch theory of climate change and emphasizes the role of the tropics for global climate change. Although the simultaneous multi-proxy approach of planktonic foraminiferal Mg/Ca, δ18O and δ44/40Ca from tropical sediment core SO-164-03-4 (16° 32.37′ N; 72° 12.31′ W; 2,744 m) from the Caribbean tend to confirm the observation by Visser et al. (2003) we interpret the shift between Mg/Ca and δ18O in core SO-164-03-4 to be due to local changes in sea-surface salinity (SSS) variations triggered by glacial/interglacial related shifts of the Inter-tropical Convergence Zone (ITCZ).

Description: Biologists studying animals in their natural environment are increasingly using sensors such as accelerometers in animal-attached ‘smart’ tags because it is widely acknowledged that this approach can enhance the understanding of ecological and behavioural processes. The potential of such tags is tempered by the difficulty of extracting animal behaviour from the sensors which is currently primarily dependent on the manual inspection of multiple time series graphs. This is time consuming and error-prone for the domain expert and is now the limiting factor for realising the value of tags in this area. We introduce TimeClassifier, a visual analytic system for the classification of time series data for movement ecologists. We deploy our system with biologists and report two real-world case studies of its use

Description: A seasonal forecast system is presented, based on the global coupled climate model MPI-ESM as used for CMIP5 simulations. We describe the initialisation of the system and analyse its predictive skill for surface temperature. The presented system is initialised in the atmospheric, oceanic, and sea ice component of the model from reanalysis/observations with full field nudging in all three components. For the initialisation of the ensemble, bred vectors with a vertically varying norm are implemented in the ocean component to generate initial perturbations. In a set of ensemble hindcast simulations, starting each May and November between 1982 and 2010, we analyse the predictive skill. Bias-corrected ensemble forecasts for each start date reproduce the observed surface temperature anomalies at 2–4 months lead time, particularly in the tropics. Niño3.4 sea surface temperature anomalies show a small root-mean-square error and predictive skill up to 6 months. Away from the tropics, predictive skill is mostly limited to the ocean, and to regions which are strongly influenced by ENSO teleconnections. In summary, the presented seasonal prediction system based on a coupled climate model shows predictive skill for surface temperature at seasonal time scales comparable to other seasonal prediction systems using different underlying models and initialisation strategies. As the same model underlying our seasonal prediction system—with a different initialisation—is presently also used for decadal predictions, this is an important step towards seamless seasonal-to-decadal climate predictions.

Description: Keilhack reported his impressions from his participation at the International Geological Congress in Russia in 1897 in several consecutive articles. In the more than 100 years since that time, a lot has changed. Apart from the totally different style of scientific presentations, with almost no illustrations, except maps, being shown during a talk, field trips were also a very special event, involving huge amounts of logistics. More than 200 people were transported to very remote areas of the European part of Russia. As well as organizing transportation by coaches and horses, places to stay overnight had to be found in large numbers and special regulations had to be issued by the government to allow access to various outcrops. Keilhacks visit of the oil-producing sites around Baku are of special interest, since they belonged obviously to the most productive ones on the globe at that time.

Description: Different genetic types of marine sediments that were deposited on the continental slope of the Kronotskii Peninsula with the rate of several tens of centimeters per thousand years during the last 20 ka have been investigated. It is established that their lithological, mineral, and chemical compositions were determined by climate changes.