ALBERT

Description: Physical, chemical, biological research and fishery oceanography This multidisciplinary cruise extended a long-term data series on (eco-)system composition and functioning of the Baltic Sea, with a focus on the deeper basins. The series has been collected in similar form since 1986. A key characteristic of the cruise is the integration of oceanographic and biological information to enhance understanding of environmental and (fish) population fluctuations, and evolutionary processes in this system. The resulting data- and sample sets support ongoing projects in the Research Unit Marine Evolutionary Ecology at GEOMAR, as well as the EU Horizon 2020 project GoJelly and several international collaborations. The spatial focus lay on the Bornholm Basin as most important spawning area of Baltic cod, but also included the Western Baltic Sea, Arkona and Gotland Basin, Gdansk Deep, and Stolpe Trench. Specific investigations included a detailed hydrological survey (oxygen, salinity, temperature) of the cruise area, plankton surveys (zoo- and ichthyplankton including gelatinous plankton, with the goal to determine the composition and the abundance and vertical and horizontal distribution of species, and to take samples for later measurements of nutritional condition), and pelagic fishery hauls. The latter served to determine stock structure, gonadal maturation, stomach contents, and egg production of sprat and cod, and to sample tissue and otolith samples for individual-level genetic and ecological analyses of cod. The abundance and distribution of fishes in the cruise area was also assessed with hydroacoustic methods. Additional cruise components were: (i) cod gonad sampling for fecundity studies and liver sampling for parasite studies, (ii) vertically resolved phytoplankton and zooplankton sampling for studies of plankton phenology (iii) in-depth sampling of planktonic food webs for dietary tracer work, (iv) sampling and experimental work of photosynthesis and respiration rates of different phytoplankton fractions.

Description: This multidisciplinary cruise extended a long-term data series on ecosystem composition and functioning of the deeper basins of the Baltic Sea that has been collected in similar form since 1987. The key characteristic of the cruise was the integration of oceanographic and biological information to enhance understanding of environmental, plankton dynamics and fish population fluctuations, and ultimately, evolutionary processes in this system. The spatial focus lay on the Bornholm Basin as most important spawning area of Baltic cod, but also included the Western Baltic Sea, Arkona and Gotland Basin, Gdansk Deep, and Stolpe Trench. All objectives of the cruise were achieved, benefiting from perfect weather conditions and flawless performance of all instruments and gear. The detailed hydrological survey (oxygen, salinity, temperature) of the entire cruise area showed higher water temperatures and an improvement of the oxygen situation in deep water layers compared to the same time period in 2018. Plankton surveys (zoo- and ichthyplankton including gelatinous plankton, with the goal to determine the composition and the abundance and vertical and horizontal distribution of species, and to take samples for later measurements of nutritional condition) showed a much higher abundance of jellyfish larvae (“ephyrae”) and small adults than in 2018. Regarding fish larvae, sprat and flounder larvae were abundant but very few cod larvae were present throughout the cruise area, both of which was consistent with the situation in previous years. Pelagic fishery hauls were carried out as planned to determine stock structure and to obtain a range of different samples (gonads, livers, stomachs, tissue samples, otoliths) for cod, whiting, sprat and herring as well as different flatfish species, and are the foundation for a range of different individual-level genetic and ecological analyses to be carried out in the laboratory on land. The abundance and distribution of fishes in the cruise area was also assessed continuously over the duration of the cruise with hydroacoustic methods. As in previous years, cod, herring, sprat and flounder dominated catches. Catches of cod increased compared to 2018, but the absence of large cod individuals in particular in Bornholm Basin was consistent with observations in previous years. Finally, the work for all additional collaborative projects, including in-depth sampling of planktonic food webs for dietary tracer work, sampling and experimental work of photosynthesis and respiration rates of different phytoplankton fractions and finally, pelagic fish stomach and plankton sampling for eDNA assessments was carried out successfully. The resulting data- and sample sets support ongoing projects in the Research Unit Marine Evolutionary Ecology at GEOMAR, as well as the EU Horizon 2020 project GoJelly and several international collaborations.

Description: Poseidon cruise 518 (leg 1 and 2) took place in the framework of the Horizon 2020 project STEMM-CCS of the EU. The project’s main goal is to develop and test strategies and technologies for the monitoring of subseafloor CO2 storage operations. In this context a small research-scale CO2 gas release experiment is planned for 2019 in the vicinity of the Goldeneye platform located in the British EEZ (central North Sea). Cruise POS518 aimed at collecting necessary oceanographic and biogeochemical baseline data for this release experiment. During Leg 1 ROV PHOCA was used to deploy MPI’s tool for high-precision measurements of O2, CO2 and pH in the bottom water at Goldeneye. In addition, ROV push cores and gravity cores were collected in the area for sediment biogeochemical analyses, and video-CTD casts were conducted to study the water column chemistry. The stereo-camera system and a horizontally looking multibeam echosounder, both, for determining gas bubble emissions at the seafloor were deployed at the Figge Maar blowout crater in the German Bight. Investigations were complemented by hydroacoustic surveys detecting gas bubble leakages at several abandoned wells in the North Sea as well as the Figge Maar. Surface water alkalinity as well as CH4, CO2, and water partial pressures in the air above the sea surface were measured continuously during the cruise. During Leg 2 three different benthic lander systems were deployed to obtain baseline data of oceanographic and biogeochemical parameters for a small research-scale CO2 gas release experiment planned for 2019. The first lander was equipped with an acoustic Doppler current profiler (ADCP), a CTD and an O2 optode. It was deployed for 6 days close to Goldeneye to obtain high resolution data which can be linked to the long-term measurements of the NOC-Lander. This lander is equipped with a suite of sensors to monitor temperature, conductivity, pressure, current speed and direction, hydro-acoustic, pH, pCO2, O2 and nutrients over a period of about 10 months with popup telemetry units for data transmission via IRIDIUM satellite telemetry every 3 months. Two short-term deployments of the Biogeochemical Observatory (BIGO) were conducted to study the molar ratio between oxygen and CO2-fluxes at the seafloor. Sediment cores obtained by gravity and multi corer were collected for sediment biogeochemical analyses and video-CTD casts were used to study the chemistry of the water column.

Description: Expedition M143 is a replacement for the originally scheduled expedition to the Marmara Sea to retrieve long term monitoring geodetic equipment. A short proposal to extend bathymetric mapping and imaging of active gas seepage in the Danube Delta region was approved and permission to operate in Romanian waters was successfully secured. Based on the results of mapping completed during the previous expedition M142 and other earlier missions to the same region, a set of survey lines and imaging targets were defined for M143. Objectives for expedition M143 were twofold and include the of use a dedicated 38 kHz single beam echo sounder installed in the moonpool of the research vessel METEOR for gas emission quantification and to complete bathymetric mapping for the detection of sub marine slope failures and mass transport deposits in associated with gas seepage and the occurrence of gas hydrates. During the active data acquisition phase of expedition M143 (December 12 to December 17, 2017) three sub-regions for gas flare imaging were visited (Lander Site from M142, S2 channel eastern flank, and shallow shelf region). A total of 1,189 line kilometers (642 nautical miles) of data were acquired. Out of these, a total of 238 km were acquired using the 38 kHz EK80 and EM710 (and partially EM122) multibeam data. Also, a full calibration of the 38 kHz echo sounder was accomplished and sound velocity data were recorded at the Lander and shallow shelf region survey sites. Bathymetric mapping using both EM systems EM122 and EM710 combined with the PARASOUND sub bottom profiler was completed in two main regions filling in data gaps in the existing multibeam coverage prior to M143. The first region was visited during the initial transit to the study region (December 14) around the region of the S2 channel head in water depths ~120 m. Here, a set of six parallel lines were acquired, totaling 70 km line lengths and covering an area of 11.5 square kilometers. The second region was in the eastern part of the Danube delta region, close to the Ukrainian border. In total 805 line kilometers and 472 square kilometers of multibeam data were acquired.

Description: The R/V SONNE expedition SO265 is the central activity of the research project "Shatsky Evolution" that is funded by the Federal Ministry of Education and Research and conducted by the GEOMAR Helmholtz Centre for Ocean Research Kiel in collaboration with international partners. The goal of the project is the investigation of the late stage evolution of Shatsky Rise, a vast, submarine volcanic plateau (Large Igneous Province) in the northwest Pacific. In particular, the project aims to investigate the transition from plateau volcanism (the main body of Shatsky Rise) to postulated hotspot track volcanism (Papanin Ridge and/or Ojin Rise seamounts). Applied methods included bathymetric mapping with the ship's own multi-beam echosounder (KONGSBERG EM 122), subbottom profiling (ATLAS PARASOUND DS P70), and rock sampling with chain bag dredges. The main working areas were the Papanin Ridge (the northern extension of Shatsky Rise) and the Ojin Rise Seamount Province (a broad belt of individual seamounts to the east of Shatsky Rise). Dredge hauls were conducted between ~36°N and ~44°N and ~163°E and ~170°E covering the entire geographic extent of both working areas. A third working area, the northern part of Shatsky Rise dominated by its Shirshov Massif, served as a contingency area and only a few dredge hauls were conducted there. In addition, sampling was successfully executed at Hokkaido Trough (45°06'N, 162°27'E), located ~320 km northwest of Papanin Ridge. A total of 72 dredge hauls in average water depths of 4,640 m were carried out during SO265. Of these, 49 (= 68%) delivered in situ volcanic rocks samples. No deployed equipment was lost or damaged. Post-cruise investigations at GEOMAR and cooperating institutions will include volcanological/petrological, geochronological, and geochemical studies. Furthermore, macro-benthic organisms were collected from the surfaces of the recovered rocks to study the diversity of deep-see invertebrates, and sediment sampling (by small sediment traps installed in the dredges) was conducted for meiofauna studies.

Description: GEOMAR's project was integrated into the large-scale collaborative project SUGAR-III with 19 partners from industry and academia that was also coordinated by GEOMAR. The ain of the project was to characterize the gas hydrate accumulations in the Danube deep-sea fan geophysically and geochemically, to develop a three-dimensional geological model of the deposit and simulate its formation over geological time scales using the hydrate module developed in the PetroMod software, to investigate the problem of geomechanical destabilization and sand production occurring during hydrate exploitation by means of high-pressure experiments, to further develop the SUGAR gas hydrate technologies on geophysical data analysis, geological basin modelling and geomechanical test units in collaboration with the industrial project partners.

Description: In the marine environment elevated electrical conductivities may be caused by sulfide mineralizations within the seafloor as well as hot saline pore fluids. Such conductive targets may be studied with suitable electromagnetic systems like the novel coil-system MARTEMIS1, which we previously used to investigate a known zone of sediment covered mineralization at the Palinuro Seamount (cruises POS483 & POS509) and in the vicinity of the TAG hydrothermal mound at the Mid Atlantic Ridge (cruise JC138). Both the Palinuro site as well as the sites in the vicinity of the TAG hydrothermal mound (Shinkai, Double Mound, MIR) are hydrothermally inactive and, thus, allowed to study, how the responses of an inductive EM system is influenced and shaped by mineralizations within the seafloor without having to consider the effect of of heated pore fluids. In the interpretation of the collected data at these inactive sites we learned that the MARTEMIS system is able to detect conductivity anomalies in the vicinity of mineralizations. (...)

Description: Infections arising from multidrug-resistant pathogenic bacteria are spreading rapidly throughout the world and threaten to become untreatable. The origins of resistance are numerous and complex, but one underlying factor is the capacity of bacteria to rapidly export drugs through the intrinsic activity of efflux pumps. In this Review, we describe recent advances that have increased our understanding of the structures and molecular mechanisms of multidrug efflux pumps in bacteria. Clinical and laboratory data indicate that efflux pumps function not only in the drug extrusion process but also in virulence and the adaptive responses that contribute to antimicrobial resistance during infection. The emerging picture of the structure, function and regulation of efflux pumps suggests opportunities for countering their activities.

Description: The Eastern Baltic cod abundance started rapidly to increase in the mid-2000s as evidenced by analytical stock assessments, due to increased recruitment and declining fishing mortality. Since 2014, the analytical stock assessment is not available, leaving the present stock status unclear and casting doubts about the magnitude of the recent increase in recruitment. Earlier studies identified main factors impacting on cod reproductive success to be related to the loss of two out of three spawning areas in the 1980s caused by lack of major Baltic inflows with a concurrent reduction in salinity and oxygen. Other important factors include prey availability for first-feeding larvae, egg predation by sprat and herring and cannibalism on juveniles, all in one way or the other related to the prevailing hydrographic conditions. These factors cannot explain increased reproductive success in the last decade, as the period was characterized by an absence of large-scale Baltic inflows since 2003 and persistent anoxic conditions in the bottom water of the deep Baltic basins. This questions the perception of the increased recruitment in later years and challenges our present understanding of cod recruitment dynamics in the Baltic Sea. In this contribution, we review evidence from the recent literature supplemented by information from latest research cruises to elucidate whether cod reproductive success indeed has increased during the last decade, and we suggest the key processes responsible for the recent dynamics in cod recruitment and outline directions for future research.

Description: Naturally produced polybrominated diphenyl ethers (PBDEs) pervade the marine environment and structurally resemble toxic man-made brominated flame retardants. PBDEs bioaccumulate in marine animals and are likely transferred to the human food chain. However, the biogenic basis for PBDE production in one of their most prolific sources, marine sponges of the order Dysideidae, remains unidentified. Here, we report the discovery of PBDE biosynthetic gene clusters within sponge-microbiome-associated cyanobacterial endosymbionts through the use of an unbiased metagenome-mining approach. Using expression of PBDE biosynthetic genes in heterologous cyanobacterial hosts, we correlate the structural diversity of naturally produced PBDEs to modifications within PBDE biosynthetic gene clusters in multiple sponge holobionts. Our results establish the genetic and molecular foundation for the production of PBDEs in one of the most abundant natural sources of these molecules, further setting the stage for a metagenomic-based inventory of other PBDE sources in the marine environment.

Description: Bacterial biofilms provide cues for the settlement of marine invertebrates such as coral larvae, and are therefore important for the resilience and recovery of coral reefs. This study aimed to better understand how ocean acidification may affect the community composition and diversity of bacterial biofilms on surfaces under naturally reduced pH conditions. Settlement tiles were deployed at coral reefs in Papua New Guinea along pH gradients created by two CO2 seeps. Biofilms on upper and lower tiles surfaces were sampled 5 and 13 months after deployment. Automated Ribosomal Intergenic Spacer Analysis was used to characterize 240 separate bacterial communities, complemented by amplicon sequencing of the bacterial 16S rRNA gene of 16 samples. Bacterial biofilms consisted predominantly of Alpha-, Gamma-, and Delta-proteobacteria, as well as Cyanobacteria, Flavobacteriia, and Cytophagia, whereas taxa that induce settlement of invertebrate larvae only accounted for a small fraction of the community. Bacterial biofilm composition was heterogeneous, with on average only ∼25% of operational taxonomic units shared between samples. Among the observed environmental parameters, pH was only weakly related to community composition (R2 ∼ 1%), and was unrelated to community richness and evenness. In contrast, biofilms strongly differed between upper and lower tile surfaces (contrasting in light exposure and grazing intensity). There also appeared to be a strong interaction between bacterial biofilm composition and the macroscopic components of the tile community. Our results suggest that on mature settlement surfaces in situ, pH does not have a strong impact on the composition of bacterial biofilms. Other abiotic and biotic factors such as light exposure and interactions with other organisms may be more important in shaping bacterial biofilms on mature surfaces than changes in seawater pH.

Description: At present, investigations of submarine massive sulfides (SMS) are mostly limited to active systems due to the available methods and technologies, which rely on the detection of water column anomalies (tempera - ture or chemical tracers) and the study of seafloor's morphology. They fail to detect sites where hydrothermal activity has ceased and former landmarks such as black smokers have been eroded or are covered by sediments. During RV Poseidon cruises POS483 (“ElectroPal”) and POS484 (”MARSITE”) we have successfully collected EM and airgun seismic data over an inactive and sediment covered SMS site at Palinuro, which had previously been found by chance in 1986 and was drilled to 5m depth during research cruise M73/2. EM measurements, carried out with the novel system MARTEMIS1, not only showed high conductivities in the vicinity of the SMS deposit, but also revealed a second anomaly, possibly a zone of buried mineralization at greater depth. During cruise POS509 previous measurements were continued and extended to get a full areal coverage of the structure to fully delineate and characterize the SMS sites. EM investigations were accompanied by measurements of the ambient electrical field (→ selfpotential (SP)) and additional geophysical (heat probe) and geological (gravity core) measurements for ground truthing and further structural insight. The combination of experiments proved to be convenient in terms of handling on the ship, as EM experiments on the one hand and measurements with heat probe and gravity coring on the other hand were performed in an alternating manner each other day. This alternating style of experiments gave each method time for adjust - ments and repairs as well as time to take a first look at results so that following investigations could be directly aimed at a specific target. As an example, an anomaly detected in the SP measurements in the NNW was used to guide the last gravity coring, which then found sulfide muds in an area where sulfides were previously not expected.

Description: A hydrodynamic model coupled with a Lagrangian particle tracking technique was utilized to simulate spatially and temporally resolved long-term environmentally related (i) size of habitat suitable for reproduction, (ii) egg/yolk-sac larval survival, (iii) separation of causes of mortality, and (iv) connectivity between spawning areas of Baltic flounder with pelagic eggs. Information on reproduction habitat requirements and mortality sources were obtained from field or laboratory studies. In our modelling study we only quantified physical processes generating heterogeneity in spatial distribution of eggs and yolk-sac larvae, as e.g. predation is not accounted for. The spatial extent of eggs and larvae represented as modelled particles is primarily determined by oxygen and salinity conditions. The reproduction habitat most suitable was determined for the Gdansk Deep, followed by the Bornholm Basin. Relatively low habitat suitability was obtained for the Arkona Basin and the Gotland Basin. The model runs also showed yolk-sac larval survival to be to a large extent affected by sedimentation. Eggs initially released in the Arkona Basin and Bornholm Basin are strongly affected by sedimentation compared with those released in the Gdansk Deep and Gotland Basin. Highest relative survival of eggs occurred in the Gdansk Deep and in the Bornholm Basin. Relatively low survival rates in the Gotland Basin were attributable to oxygen-dependent mortality. Oxygen content had almost no impact on survival in the Arkona Basin. For all spawning areas mortality caused by lethally low temperatures was only evident after severe winters. Buoyancy of eggs and yolk-sac larvae in relation to topographic features appear as a barrier for the transport of eggs and yolk-sac larvae and potentially limits the connectivity of early life stages between the different spawning areas.

Description: The round goby (Neogobius melanostomus) is extremely invasive fish species, capable to reach high abundance and make significant impact on invaded ecosystem. First round gobies occured in the Lithuanian part of the Baltic Sea in 2002. The population passed establishment (2002-2010), expansion (2011-2012) and adjustment (2013-2015) phases. Rapid round goby abundance increment induced dramatic decline of its major prey - the blue mussel (Mytilus edulis), which in turn negatively affected population of wintering long-tailed duck (Clangula hyemalis). Food competition between round goby and long-tailed duck was evaluated analysing changes in their diet composition, feeding efficiency and feeding niche overlap during different round goby invasion phases. During establishment both species preyed mainly on M. edulis; during expansion, the diet of round goby was dominated by M. edulis, Crangon crangon and Macoma balthica, while in the last invasion period it shifted to polychaetes. Long-tailed duck shifted its diet from epibenthic blue mussel to fish prey during round goby expansion and adjustment phases. Feeding efficiency of the round goby decreased from 100% (percentage of full guts) determined during establishment to 80% and 68% during expansion and adjustment phases, respectively. The highest percentage of feeding long-tailed ducks was observed in the beginning of round goby invasion (74%), it dramatically declined during 2011-2012 (26%) and recovered (53%) during 2015-2016. Feeding niche overlap between round goby and long-tailed duck was biologically significant during round goby establishment, but it lost significance after drastic decline of the blue mussel in natural environment.

Description: Der Dorschbestand in der westlichen Ostsee befindet sich seit Jahren außerhalb sicherer biologischer Grenzen. Diese Situation hat sich jetzt weiter verschlechtert, so dass im Jahr 2016 die Anzahl der einjährigen Jungdorsche nur 3.5% des durchschnittlichen Nachwuchses betrug. Der Internationale Rat für Meeresforschung (ICES) hat deshalb eine drastische Reduzierung der kommerziellen Fänge im Jahr 2017 angeraten. Leider ist die Politik dieser Empfehlung nicht gefolgt und es sind etwa doppelt so hohe Fänge erlaubt worden. In Deutschland beschlossene finanzielle Hilfsmittel für die Fischer tragen ebenfalls nicht zur Verringerung dieser Fänge bei. Die wenigen einjährigen Dorsche von 2016 werden daher in 2017 stark befischt, bevor sie im Jahr 2018 den Elternbestand stellen. Es ist zu befürchten, dass der Nachwuchs von diesem viel zu kleinen Elternbestand ganz ausbleibt und der westliche Dorschbestand im Jahr 2019 zusammenbricht, mit den entsprechenden drastischen Folgen für Berufs- und Angelfischerei. Um den Fortbestand des westlichen Dorsches zu sichern, schlagen wir vor, die Fischerei und Angelei auf Dorsch in der westlichen Ostsee für zwei Jahre einzustellen, mit Ausgleichszahlungen für Berufsfischer und Angelkutter.

Description: Practical course at sea for students of Biological Oceanography (MNF-bioc-301)

Description: The majority of M〉8.5 active plate boundary earthquakes has hypocenters located beneath the oceans in subduction zones. Post-hoc analysis shows that most of the surface deformation related to co-seismic stress release takes place on the seafloor, in many cases unleashing major tsunamis. The structure and morphology of the seafloor and shallow subbottom thus stores crucial information on sub-seafloor processes, such as permanent deformation by seismic slip or aseismic creep within the overriding plate and earthquake and tsunami generation. We have mapped the seafloor seaward of the Northern Chilean coast between about 19°S and 22°S down to the Northern Chile deep sea trench, using the ship-based Multibeam Echosounder EM122, Parasound, and AUV (autonomous underwater vehicle) – in selected subareas - at sufficient resolution to identify active tectonic fault structures and submarine mass wasting structures, to quantitatively assess young and active deformation of the overriding plate in the area, and quantify the extent of recent catastrophic downslope mass movements of sediment. Furthermore, the investigations serve as a site survey for the deployment of the GeoSEA seafloor geodetic array, to be installed immediately after completion of this cruise. The investigations were made timely by the 1st April 2014 Pisagua M=8.2 earthquake, that ruptured the plate interface in the northern part of the area of investigation. The central and southern parts are located in the last remaining locked seimotectonic segment along the Chilean active margin. In addition to providing the first data base for geomorphological and tectonic interpretation of geo-processes at the seafloor, the bathymetric mapping done during SO244 Leg 1 will provide an important data reference for possible post-earthquake surveys once this seismotectonic segment will have broken in the future.

Description: To the Editor: We congratulate Halsey et al. for their important discussion of the random nature of P values in an earlier issue of this journal1. P values from identical experiments can differ greatly in a way that is surprising to many2, 3, 4, 5, 6. The failure to appreciate this…

Description: The approach to fisheries termed “balanced harvesting” (BH) calls for fishing across the widest possible range of species, stocks, and sizes in an ecosystem, in proportion to their natural productivity, so that the relative size and species composition is maintained. Such fishing is proposed to result in higher catches with less negative impact on exploited populations and ecosystems. This study examines the models and the empirical evidence put forward in support of BH. It finds that the models used unrealistic settings with regard to life history (peak of cohort biomass at small sizes), response to fishing (strong compensation of fishing mortality by reduced natural mortality), and economics (uniform high cost of fishing and same ex-vessel price for all species and sizes), and that empirical evidence of BH is scarce and questionable. It concludes that evolutionary theory, population dynamics theory, ecosystem models with realistic assumptions and settings, and widespread empirical evidence do not support the BH proposal. Rather, this body of evidence suggests that BH will not help but will hinder the policy changes needed for the rebuilding of ecosystems, healthy fish populations, and sustainable fisheries.

Description: Cruise Report POS493 (AUV DeDAVE) – Canary Islands, January 26th to February 1st, 2016 - Test cruise for AUV “DeDAvE” around the Canary Islands

Description: High-throughput techniques based on restriction site-associated DNA sequencing (RADseq) are enabling the low-cost discovery and genotyping of thousands of genetic markers for any species, including non-model organisms, which is revolutionizing ecological, evolutionary and conservation genetics. Technical differences among these methods lead to important considerations for all steps of genomics studies, from the specific scientific questions that can be addressed, and the costs of library preparation and sequencing, to the types of bias and error inherent in the resulting data. In this Review, we provide a comprehensive discussion of RADseq methods to aid researchers in choosing among the many different approaches and avoiding erroneous scientific conclusions from RADseq data, a problem that has plagued other genetic marker types in the past.

Description: The R/V SONNE expedition SO-249 is part of the research project BERING, conducted in the framework of the Russian-German Agreement on Marine and Polar Research and in close cooperation with U.S. American colleagues. The overarching goal of BERING is to elucidate the magmatic and tectonic evolution of the Bering Sea and its margins over the past ≥50 m.y. In particular, BERING investigates the physical and chemical conditions that control the development of subduction zones, including subduction initiation, evolution of mature arc systems, and the impact of subduction volcanism on the environment. R/V SONNE cruise SO- 249 BERING conducted geological, morphological, and biological studies in the in western the Aleutians, the Pacific seafloor subducting beneath the Aleutians and northern Kamchatka, and in the western Bering Sea. Besides extensive multi-beam mapping and sediment echo-sounder profiling, total of 150 dredge hauls have been conducted on the two legs of cruise SO-249. Of these, 91 delivered massive magmatic and/or metamorphic rocks, 34 volcaniclastic rocks including breccias containing lava fragments, 64 sedimentary rocks, and 19 Mn-Fe-Oxide crusts and nodules. No equipment was lost or seriously damaged. SO-249 achieved its major goals and the SO-249 sample set represents the most detailed sampling of the working areas to date. The on shore work program at Russian, German, and U.S.-American institutions includes geochronological, petrological and geochemical studies on igneous samples obtained during the cruise. The results of BERING will be integrated with those of previous campaigns (e.g. KOMEX, KALMAR), and work carried out within the World Oceans and GeoPRISMS initiatives. The main goal of biological sampling was to survey the benthic biodiversity in the study area. In addition, fresh specimens pertaining to specific taxa (Cnidaria, Brachiopoda, Cephalopoda, Echinodermata) were collected to supplement ongoing research projects. Of the 150 dredges taken, 150 (100%) contained sediment and 112 (74.7%) contained macrofauna. In addition to the 150 sediment samples, almost 1,500 single benthic, benthopelagic, and pelagic macrofaunal organisms were obtained. The majority of the objectives of biological sampling were reached, in particular with regard to obtaining fresh tissue for immunohistochemical, genomic, and transcriptomic analysis from various brachiopod and ophiuroid species.

Description: Dates of Cruise: 28. September to 01. October 2015 Projects: Student course CAU Kiel (MNF-Pher-110b)

Description: Remarkable technological advances have revealed ever more properties and behaviours of individual microorganisms, but the novel data generated by these techniques have not yet been fully exploited. In this Opinion article, we explain how individual-based models (IBMs) can be constructed based on the findings of such techniques and how they help to explore competitive and cooperative microbial interactions. Furthermore, we describe how IBMs have provided insights into self-organized spatial patterns from biofilms to the oceans of the world, phage–CRISPR dynamics and other emergent phenomena. Finally, we discuss how combining individual-based observations with IBMs can advance our understanding at both the individual and population levels, leading to the new approach of microbial individual-based ecology (μIBE).

Description: Bacteria use quorum sensing to orchestrate gene expression programmes that underlie collective behaviours. Quorum sensing relies on the production, release, detection and group-level response to extracellular signalling molecules, which are called autoinducers. Recent work has discovered new autoinducers in Gram-negative bacteria, shown how these molecules are recognized by cognate receptors, revealed new regulatory components that are embedded in canonical signalling circuits and identified novel regulatory network designs. In this Review we examine how, together, these features of quorum sensing signal–response systems combine to control collective behaviours in Gram-negative bacteria and we discuss the implications for host–microbial associations and antibacterial therapy.

Description: Mesoscale ocean eddies are ubiquitous coherent rotating structures of water with radial scales on the order of 100 kilometers. Eddies play a key role in the transport and mixing of momentum and tracers across the World Ocean. We present a global daily mesoscale ocean eddy dataset that contains ~45 million mesoscale features and 3.3 million eddy trajectories that persist at least two days as identified in the AVISO dataset over a period of 1993–2014. This dataset, along with the open-source eddy identification software, extract eddies with any parameters (minimum size, lifetime, etc.), to study global eddy properties and dynamics, and to empirically estimate the impact eddies have on mass or heat transport. Furthermore, our open-source software may be used to identify mesoscale features in model simulations and compare them to observed features. Finally, this dataset can be used to study the interaction between mesoscale ocean eddies and other components of the Earth System.

Description: Microorganisms produce a wealth of structurally diverse specialized metabolites with a remarkable range of biological activities and a wide variety of applications in medicine and agriculture, such as the treatment of infectious diseases and cancer, and the prevention of crop damage. Genomics has revealed that many microorganisms have far greater potential to produce specialized metabolites than was thought from classic bioactivity screens; however, realizing this potential has been hampered by the fact that many specialized metabolite biosynthetic gene clusters (BGCs) are not expressed in laboratory cultures. In this Review, we discuss the strategies that have been developed in bacteria and fungi to identify and induce the expression of such silent BGCs, and we briefly summarize methods for the isolation and structural characterization of their metabolic products.

Description: Cultivable Actinobacteria are the largest source of microbially derived bioactive molecules. The high demand for novel antibiotics highlights the need for exploring novel sources of these bacteria. Microbial symbioses with sessile macro-organisms, known to contain bioactive compounds likely of bacterial origin, represent an interesting and underexplored source of Actinobacteria. We studied the diversity and potential for bioactive-metabolite production of Actinobacteria associated with two marine lichens ( Lichina confinis and L. pygmaea ; from intertidal and subtidal zones) and one littoral lichen ( Roccella fuciformis ; from supratidal zone) from the Brittany coast (France), as well as the terrestrial lichen Collema auriforme (from a riparian zone, Austria). A total of 247 bacterial strains were isolated using two selective media. Isolates were identified and clustered into 101 OTUs (98% identity) including 51 actinobacterial OTUs. The actinobacterial families observed were: Brevibacteriaceae, Cellulomonadaceae, Gordoniaceae, Micrococcaceae, Mycobacteriaceae, Nocardioidaceae, Promicromonosporaceae, Pseudonocardiaceae, Sanguibacteraceae and Streptomycetaceae. Interestingly, the diversity was most influenced by the selective media rather than lichen species or the level of lichen thallus association. The potential for bioactive-metabolite biosynthesis of the isolates was confirmed by screening genes coding for polyketide synthases types I and II. These results show that littoral lichens are a source of diverse potentially bioactive Actinobacteria.

Description: Vital processes relevant for exploited stocks, for example growth, predation and recruitment are closely related to the environmental conditions. Here, we present a generic method to include state of the art knowledge on environmental impacts and environmental forecasting into short-term predictions and the formulation of environment-based harvest control rules for exploited stocks. The method consists of three elements: First, the linkage between environmental parameters and stock dynamics, second the short-term prediction of both environment and stock dynamics, and third the scaling of otherwise constant reference values for fishing mortality in accordance with the environmental situation. The method is exemplified for Eastern Baltic cod. Recruitment is treated as dependent on oxygen conditions, and the formulation of the proposed fishing intensity is accounting for the actual oxygen conditions and predicted conditions for the year following the assessment year. Finally, the resulting advice is compared to advice that has been given not accounting for the oxygen conditions.

Description: Large amounts of the greenhouse gas methane are released from the seabed to the water column1, where it may be consumed by aerobic methanotrophic bacteria2. The size and activity of methanotrophic communities, which determine the amount of methane consumed in the water column, are thought to be mainly controlled by nutrient and redox dynamics3–7. Here, we report repeated measurements of methanotrophic activity and community size at methane seeps west of Svalbard, and relate them to physical water mass properties and modelled ocean currents. We show that cold bottom water, which contained a large number of aerobic methanotrophs, was displaced by warmer water with a considerably smaller methanotrophic community within days. Ocean current simulations using a global ocean/sea-ice model suggest that this water mass exchange is consistent with short-term variations in the meandering West Spitsbergen Current. We conclude that the shift from an offshore to a nearshore position of the current can rapidly and severely reduce methanotrophic activity in the water column. Strong fluctuating currents are common at many methane seep systems globally, and we suggest that they affect methane oxidation in the water column at other sites, too.

Description: Climate change is altering oceanic conditions in a complex manner, and the concurrent amendment of multiple properties will modify environmental stress for primary producers. So far, global modelling studies have focused largely on how alteration of individual properties will affect marine life. Here, we use global modelling simulations in conjunction with rotated factor analysis to express model projections in terms of regional trends in concomitant changes to biologically influential multi-stressors. Factor analysis demonstrates that regionally distinct patterns of complex oceanic change are evident globally. Preliminary regional assessments using published evidence of phytoplankton responses to complex change reveal a wide range of future responses to interactive multi-stressors with 〈20–300% shifts in phytoplankton physiological rates, and many unexplored potential interactions. In a future ocean, provinces will encounter different permutations of change that will probably alter the dominance of key phytoplankton groups and modify regional productivity, ecosystem structure and biogeochemistry. Consideration of regionally distinct multi-stressor patterns can help guide laboratory and field studies as well as the interpretation of interactive multi-stressors in global models.

Description: Reflection on the rapidly growing field of ocean acidification research highlights priorities for future research on the changing ocean.

Description: Thin oceanic crust is formed by decompression melting of the upper mantle at mid-ocean ridges, but the origin of the thick and buoyant continental crust is enigmatic. Juvenile continental crust may form from magmas erupted above intraoceanic subduction zones, where oceanic lithosphere subducts beneath other oceanic lithosphere. However, it is unclear why the subduction of dominantly basaltic oceanic crust would result in the formation of andesitic continental crust at the surface. Here we use geochemical and geophysical data to reconstruct the evolution of the Central American land bridge, which formed above an intra-oceanic subduction system over the past 70Myr. We find that the geochemical signature of erupted lavas evolved from basaltic to andesitic about 10Myr ago - coincident with the onset of subduction of more oceanic crust that originally formed above the Galápagos mantle plume. We also find that seismic P-waves travel through the crust at velocities intermediate between those typically observed for oceanic and continental crust. We develop a continentality index to quantitatively correlate geochemical composition with the average P-wave velocity of arc crust globally. We conclude that although the formation and evolution of continents may involve many processes, melting enriched oceanic crust within a subduction zone - a process probably more common in the Archaean - can produce juvenile continental crust.

Description: The stomachs of most vertebrates operate at an acidic pH of 2 generated by the gastric H+/K+-ATPase located in parietal cells. The acidic pH in stomachs of vertebrates is believed to aid digestion and to protect against environmental pathogens. Little attention has been placed on whether acidic gastric pH regulation is a vertebrate character or a deuterostome ancestral trait. Here, we report alkaline conditions up to pH 10.5 in the larval digestive systems of ambulacraria (echinoderm + hemichordate), the closest relative of the chordate. Microelectrode measurements in combination with specific inhibitors for acid-base transporters and ion pumps demonstrated that the gastric alkalization machinery in sea urchin larvae is mainly based on direct H+ secretion from the stomach lumen and involves a conserved set of ion pumps and transporters. Hemichordate larvae additionally utilized HCO 3- transport pathways to generate even more alkaline digestive conditions. Molecular analyses in combination with acidification experiments supported these findings and identified genes coding for ion pumps energizing gastric alkalization. Given that insect larval guts were also reported to be alkaline, our discovery raises the hypothesis that the bilaterian ancestor utilized alkaline digestive system while the vertebrate lineage has evolved a strategy to strongly acidify their stomachs.

Description: Symbiotic relationships between phytoplankton and N-2-fixing microorganisms play a crucial role in marine ecosystems. The abundant and widespread unicellular cyanobacteria group A (UCYN-A) has recently been found to live symbiotically with a haptophyte. Here, we investigated the effect of nitrogen (N), phosphorus (P), iron (Fe) and Saharan dust additions on nitrogen (N-2) fixation and primary production by the UCYN-A-haptophyte association in the subtropical eastern North Atlantic Ocean using nifH expression analysis and stable isotope incubations combined with single-cell measurements. N-2 fixation by UCYN-A was stimulated by the addition of Fe and Saharan dust, although this was not reflected in the nifH expression. CO2 fixation by the haptophyte was stimulated by the addition of ammonium nitrate as well as Fe and Saharan dust. Intriguingly, the single-cell analysis using nanometer scale secondary ion mass spectrometry indicates that the increased CO2 fixation by the haptophyte in treatments without added fixed N is likely an indirect result of the positive effect of Fe and/or P on UCYN-A N-2 fixation and the transfer of N-2-derived N to the haptophyte. Our results reveal a direct linkage between the marine carbon and nitrogen cycles that is fuelled by the atmospheric deposition of dust. The comparison of single-cell rates suggests a tight coupling of nitrogen and carbon transfer that stays balanced even under changing nutrient regimes. However, it appears that the transfer of carbon from the haptophyte to UCYN-A requires a transfer of nitrogen from UCYN-A. This tight coupling indicates an obligate symbiosis of this globally important diazotrophic association.

Description: Quasi-decadal variability in solar irradiance has been suggested to exert a substantial effect on Earth’s regional climate. In the North Atlantic sector, the 11-year solar signal has been proposed to project onto a pattern resembling the North Atlantic Oscillation (NAO), with a lag of a few years due to ocean-atmosphere interactions. The solar/NAO relationship is, however, highly misrepresented in climate model simulations with realistic observed forcings. In addition, its detection is particularly complicated since NAO quasi-decadal fluctuations can be intrinsically generated by the coupled ocean-atmosphere system. Here we compare two multi-decadal ocean-atmosphere chemistry-climate simulations with and without solar forcing variability. While the experiment including solar variability simulates a 1–2-year lagged solar/NAO relationship, comparison of both experiments suggests that the 11-year solar cycle synchronizes quasi-decadal NAO variability intrinsic to the model. The synchronization is consistent with the downward propagation of the solar signal from the stratosphere to the surface.

Description: Dissolved oxygen in sea water affects marine habitats and biogeochemical cycles. Oceanic zones with oxygen deficits represent 7% of the volume and 8% of the area of the oceans, and are thought to be expanding. One of the most pronounced lies in the region off Peru, where mesoscale activity in the form of fronts and eddies is strong. Here, we study the dynamics of the Peruvian oxygen minimum zone in a Lagrangian framework, using a coupled physical-biogeochemical numerical model and finite-size Lyapunov exponent fields, to evaluate the role of mesoscale activity. We find that, at depths between 380 and 600 m, mesoscale structures have two distinct roles. First, their mean positions and paths delimit and maintain the oxygen minimum zone boundaries. Second, their high-frequency fluctuations inject oxygen across the oxygen minimum zone boundaries and eddy fluxes are one order of magnitude higher than mean oxygen fluxes. We conclude that these eddy fluxes contribute to the ventilation of the Peruvian oxygen minimum zone.

Description: The symbiotic association of corals and unicellular algae of the genus Symbiodinium in the southern Persian/Arabian Gulf (PAG) display an exceptional heat tolerance, enduring summer peak temperatures of up to 36 °C. As yet, it is not clear whether this resilience is related to the presence of specific symbiont types that are exclusively found in this region. Therefore, we used molecular markers to identify the symbiotic algae of three Porites species along 〉1000 km of coastline in the PAG and the Gulf of Oman and found that a recently described species, Symbiodinium thermophilum, is integral to coral survival in the southern PAG, the world’s hottest sea. Despite the geographic isolation of the PAG, we discovered that representatives of the S. thermophilum group can also be found in the adjacent Gulf of Oman providing a potential source of thermotolerant symbionts that might facilitate the adaptation of Indian Ocean populations to the higher water temperatures expected for the future. However, corals from the PAG associated with S. thermophilum show strong local adaptation not only to high temperatures but also to the exceptionally high salinity of their habitat. We show that their superior heat tolerance can be lost when these corals are exposed to reduced salinity levels common for oceanic environments elsewhere. Consequently, the salinity prevailing in most reefs outside the PAG might represent a distribution barrier for extreme temperature-tolerant coral/Symbiodinium associations from the PAG.

Description: The scientific work during SO242/2 (28. August - 01. October 2015) was part of the JPIO Pilot Action ‘Ecological Aspects of Deep-Sea Mining‘. The main goal was to study the potential long-term ecological impact of anthropogenic disturbances on the deep-sea floor from mining polymetallic Mn-nodules. The expedition SO242 built on studies of the former German TUSCH projects (1989-1996) with four RV SONNE cruises to the DISCOL Experimental Area in the Peru Basin, South Pacific (7°S, 88.5° W; 4150 m water depth) between 1989 and 1996 (DISCOL and ATESEPP projects). The integrated ecological studies were carried out within and next to plough tracks of the original DISCOL experiment 1989, which mimicked seafloor disturbances similar to those occurring during nodule mining. Leg 242/2 extended the investigations started during leg 242/1 with a focus on biogeochemical and biological sampling and observations, including comparative studies of the composition of benthic communities (all size classes) as well as of ecosystem functions (remineralization rates, transfer of matter and energy in food webs, ecotoxicology). In addition, observations were continued of the physicochemical characteristics of the DEA, including the overlying benthic boundary layer. The nodule fields surrounding the DEA were used as references for undisturbed areas. A large proportion of the work was based on autonomous instruments and sensor modules that were deployed by means of ROV and lander systems. In addition, ROV-manipulated and telemetryguided instruments such as the Ocean Floor Observatory System were used for targeted sampling and surveys. Food-web experiments including some small-scale disturbances were carried out and sampled directly at the seafloor by the ROV.

Description: Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12 degrees latitudes featuring a steep temperature gradient between the northern (28.5 degrees N, 21-27 degrees C) and southern (16.5 degrees N, 28-33 degrees C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28-29 degrees C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals

Description: Over the past 60 years, both average daily precipitation intensity and extreme precipitation have increased in many regions1, 2, 3. Part of these changes, or even individual events4, 5, have been attributed to anthropogenic warming6, 7. Over the Black Sea and Mediterranean region, the potential for extreme summertime convective precipitation has grown8 alongside substantial sea surface temperature increase. A particularly devastating convective event experienced in that region was the July 2012 precipitation extreme near the Black Sea town of Krymsk9. Here we study the effect of sea surface temperature (SST) increase on convective extremes within the region, taking the Krymsk event as a showcase example. We carry out ensemble sensitivity simulations with a convection-permitting atmospheric model and show the crucial role of SST increase in the extremeness of the event. The enhancement of lower tropospheric instability due to the current warmer Black Sea allows deep convection to be triggered, increasing simulated precipitation by more than 300% relative to simulations with SSTs characteristic of the early 1980s. A highly nonlinear precipitation response to incremental SST increase suggests that the Black Sea has exceeded a regional threshold for the intensification of convective extremes. The physical mechanism we identify indicates that Black Sea and Mediterranean coastal regions may face abrupt amplifications of convective precipitation under continued SST increase, and illustrates the limitations of thermodynamical bounds for estimating the temperature scaling of convective extremes.

Description: To date, the parameters that determine the rupture area of great subduction zone earthquakes remain contentious. On 1 April 2014, the Mw 8.1 Iquique earthquake ruptured a portion of the well-recognized northern Chile seismic gap but left large highly coupled areas un-ruptured. Marine seismic reflection and swath bathymetric data indicate that structural variations in the subducting Nazca Plate control regional-scale plate-coupling variations, and the limited extent of the 2014 earthquake. Several under-thrusting seamounts correlate to the southward and up-dip arrest of seismic rupture during the 2014 Iquique earthquake, thus supporting a causal link. By fracturing of the overriding plate, the subducting seamounts are likely further responsible for reduced plate-coupling in the shallow subduction zone and in a lowly coupled region around 20.5°S. Our data support that structural variations in the lower plate influence coupling and seismic rupture offshore Northern Chile, whereas the structure of the upper plate plays a minor role.

Description: Oceanic dissolved organic carbon (DOC) is an important carbon pool, similar in magnitude to atmospheric CO2, but the fate of its oldest forms is not well understood. Hot hydrothermal circulation may facilitate the degradation of otherwise un-reactive dissolved organic matter, playing an important role in the long-term global carbon cycle. The oldest, most recalcitrant forms of DOC, which make up most of oceanic DOC, can be recovered by solid-phase extraction. Here we present measurements of solid-phase extractable DOC from samples collected between 2009 and 2013 at seven vent sites in the Atlantic, Pacific and Southern oceans, along with magnesium concentrations, a conservative tracer of water circulation through hydrothermal systems. We find that magnesium and solid-phase extractable DOC concentrations are correlated, suggesting that solid-phase extractable DOC is almost entirely lost from solution through mineralization or deposition during circulation through hydrothermal vents with fluid temperatures of 212-401°C. In laboratory experiments, where we heated samples to 380°C for four days, we found a similar removal efficiency. We conclude that thermal degradation alone can account for the loss of solid-phase extractable DOC in natural hydrothermal systems, and that its maximum lifetime is constrained by the timescale of hydrothermal cycling, at about 40 million years

Description: The cruise SO239 EcoResponse took place between 11th of March and 30th of April 2015. Aim of the cruise was to study the biodiversity, geological and geochemical settings across a productivity gradient in the CCZ. Also to study the genetic connectivity between distant deepsea populations, to compare the fauna from seamounts with the fauna living attached to the nodules and to sample an APEI for the first time. The AUV was used to test the usefulness of photographic and side-scan sonar survey for future monitoring of mining activities. We visited 6 working areas in 4 ISA contractor areas (from BGR, IOM, DEME, Ifremer) and the APEI number 3. On all sites sediment samples were taken with the Multicorer, Box-Corer and Gravity Corer. Additionally epibenthic fauna and scavengers were sampled with the Epibenthic Sledge and Amphipod Trap, respectively. CTD cast and water samples were taken on each of the areas. An AUV was used to perform detail bathymetric mapping in addition to side-scan sonar and photographic surveys. ROV was used to sample megafauna organisms, to sample sediments inside dredge tracks, and to perform video transect.

Description: Cold-water corals (CWC) are widely distributed around the world forming extensive reefs at par with tropical coral reefs. They are hotspots of biodiversity and organic matter processing in the world’s deep oceans. Living in the dark they lack photosynthetic symbionts and are therefore considered to depend entirely on the limited flux of organic resources from the surface ocean. While symbiotic relations in tropical corals are known to be key to their survival in oligotrophic conditions, the full metabolic capacity of CWC has yet to be revealed. Here we report isotope tracer evidence for efficient nitrogen recycling, including nitrogen assimilation, regeneration, nitrification and denitrification. Moreover, we also discovered chemoautotrophy and nitrogen fixation in CWC and transfer of fixed nitrogen and inorganic carbon into bulk coral tissue and tissue compounds (fatty acids and amino acids). This unrecognized yet versatile metabolic machinery of CWC conserves precious limiting resources and provides access to new nitrogen and organic carbon resources that may be essential for CWC to survive in the resource-depleted dark ocean.

Description: The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, ‘Agulhas leakage’, forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870–2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. This is relevant for climate in the North Atlantic

Description: Sea-level rise1 is one of the most pressing aspects of anthropogenic global warming with far-reaching consequences for coastal societies. However, sea-level rise did2, 3, 4, 5, 6, 7 and will strongly vary from coast to coast8, 9, 10. Here we investigate the long-term internal variability effects on centennial projections of dynamic sea level (DSL), the local departure from the globally averaged sea level. A large ensemble of global warming integrations has been conducted with a climate model, where each realization was forced by identical CO2 increase but started from different atmospheric and oceanic initial conditions. In large parts of the mid- and high latitudes, the ensemble spread of the projected centennial DSL trends is of the same order of magnitude as the globally averaged steric sea-level rise, suggesting that internal variability cannot be ignored when assessing twenty-first-century DSL trends. The ensemble spread is considerably reduced in the mid- to high latitudes when only the atmospheric initial conditions differ while keeping the oceanic initial state identical; indicating that centennial DSL projections are strongly dependent on ocean initial conditions.

Description: Restructure data-gathering and evaluation networks to address climate change, energy, food, health and water provision, say Yonglong Lu and colleagues.

Description: Global mean surface warming has stalled since the end of the twentieth century1, 2, but the net radiation imbalance at the top of the atmosphere continues to suggest an increasingly warming planet. This apparent contradiction has been reconciled by an anomalous heat flux into the ocean3, 4, 5, 6, 7, 8, induced by a shift towards a La Niña-like state with cold sea surface temperatures in the eastern tropical Pacific over the past decade or so. A significant portion of the heat missing from the atmosphere is therefore expected to be stored in the Pacific Ocean. However, in situ hydrographic records indicate that Pacific Ocean heat content has been decreasing9. Here, we analyse observations along with simulations from a global ocean–sea ice model to track the pathway of heat. We find that the enhanced heat uptake by the Pacific Ocean has been compensated by an increased heat transport from the Pacific Ocean to the Indian Ocean, carried by the Indonesian throughflow. As a result, Indian Ocean heat content has increased abruptly, which accounts for more than 70% of the global ocean heat gain in the upper 700 m during the past decade. We conclude that the Indian Ocean has become increasingly important in modulating global climate variability.

Description: An index of water-circulation strength in the North Atlantic Ocean has been derived from sea-level measurements. This provides fresh evidence of the ocean's leading role in multidecadal climate variability. See Letter p.508

Description: Increasingly, spatial geochemical zonation, present as geographically distinct, subparallel trends, is observed along hotspot tracks, such as Hawaii and the Galapagos. The origin of this zonation is currently unclear. Recently zonation was found along the last B70 Myr of the Tristan-Gough hotspot track. Here we present new Sr–Nd–Pb–Hf isotope data from the older parts of this hotspot track (Walvis Ridge and Rio Grande Rise) and re-evaluate published data from the Etendeka and Parana flood basalts erupted at the initiation of the hotspot track. We show that only the enriched Gough, but not the less-enriched Tristan, component is present in the earlier (70–132 Ma) history of the hotspot. Here we present a model that can explain the temporal evolution and origin of plume zonation for both the Tristan-Gough and Hawaiian hotspots, two end member types of zoned plumes, through processes taking place in the plume sources at the base of the lower mantle.

Description: As a result of the raising CO2-emissions and the resultant ocean acidification (decreasing pH and carbonate ion concentration), the impact on marine organism that build their skeletons and protective shells with calcium carbonate (e.g., mollusks, sea urchins, coccolithophorids, and stony corals) becomes more and more detrimental. In the last few years, many experiments with tropical reef building corals have shown, that a lowering of the carbonate ion concentration significantly reduces calcification rates and therefore growth (e.g., Gattuso et al. 1999; Langdon et al. 2000, 2003; Marubini et al. 2001, 2002). In the middle of this century, many tropical coral reefs may well erode faster than they can rebuild. Cold-water corals are living in an environment (high geographical latitude, cold and deep waters) already close to a critical carbonate ion concentration below calcium carbonate dissolves. Actual projections indicate that about 70% of the currently known Lophelia reef structures will be in serious danger until the end of the century (Guinotte et al. 2006). Therefore L. pertusa was cultured at GEOMAR to determine its long-term response to ocean acidification. Our work has revealed that – unexpectedly and controversially to the majority of warm-water corals – this species is potentially able to cope with elevated concentrations of CO2. Whereas short-term (1 week) high CO2 exposure resulted in a decline of calcification by 26-29 % for a pH decrease of 0.1 units and net dissolution of calcium carbonate, L. pertusa was capable to acclimate to acidified conditions in long-term (6 months) incubations, leading to slightly enhanced rates of calcification (Form & Riebesell, 2012). But all these studies were carried out in the laboratory under controlled conditions without considering natural variability and ecosystem interactions with the associated fauna. Moreover, only very little is known about the nutrition (food sources and quantity) of cold-water corals in their natural habitat. In a multifactorial laboratory study during BIOACID phase II we could show that food availability is one of the key drivers that promote the capability of these organisms to withstand environmental pressures such as alterations in the carbonate chemistry and temperature (Büscher, Form & Riebesell, in prep.). To take into account the influences of natural fluctuations and interactions (e.g. bioerosion), we aim to merge in-situ results from the two research cruises POS455 and POS473 with laboratory experimental studies for a comprehensive understanding of likely ecosystem responses under past, present and future environmental conditions.

Description: This manual represents a review of the potential sources and methods to be applied when providing prior information to Bayesian stock assessments and marine risk analysis. The manual is compiled as a product of the EC Framework 7 ECOKNOWS project (www.ecoknows.eu). The manual begins by introducing the basic concepts of Bayesian inference and the role of prior information in the inference. Bayesian analysis is a mathematical formalization of a sequential learning process in a probabilistic rationale. Prior information (also called ”prior knowledge”, ”prior belief”, or simply a ”prior”) refers to any existing relevant knowledge available before the analysis of the newest observations (data) and the information included in them. Prior information is input to a Bayesian statistical analysis in the form of a probability distribution (a prior distribution) that summarizes beliefs about the parameter concerned in terms of relative support for different values. Apart from specifying probable parameter values, prior information also defines how the data are related to the phenomenon being studied, i.e. the model structure. Prior information should reflect the different degrees of knowledge about different parameters and the interrelationships among them. Different sources of prior information are described as well as the particularities important for their successful utilization. The sources of prior information are classified into four main categories: (i) primary data, (ii) literature, (iii) online databases, and (iv) experts. This categorization is somewhat synthetic, but is useful for structuring the process of deriving a prior and for acknowledging different aspects of it. A hierarchy is proposed in which sources of prior information are ranked according to their proximity to the primary observations, so that use of raw data is preferred where possible. This hierarchy is reflected in the types of methods that might be suitable – for example, hierarchical analysis and meta-analysis approaches are powerful, but typically require larger numbers of observations than other methods. In establishing an informative prior distribution for a variable or parameter from ancillary raw data, several steps should be followed. These include the choice of the frequency distribution of observations which also determines the shape of prior distribution, the choice of the way in which a dataset is used to construct a prior, and the consideration related to whether one or several datasets are used. Explicitly modelling correlations between parameters in a hierarchical model can allow more effective use of the available information or more knowledge with the same data. Checking the literature is advised as the next approach. Stock assessment would gain much from the inclusion of prior information derived from the literature and from literature compilers such as FishBase (www.fishbase.org), especially in data-limited situations. The reader is guided through the process of obtaining priors for length–weight, growth, and mortality parameters from FishBase. Expert opinion lends itself to data-limited situations and can be used even in cases where observations are not available. Several expert elicitation tools are introduced for guiding experts through the process of expressing their beliefs and for extracting numerical priors about variables of interest, such as stock–recruitment dynamics, natural mortality, maturation, and the selectivity of fishing gears. Elicitation of parameter values is not the only task where experts play an important role; they also can describe the process to be modelled as a whole. Information sources and methods are not mutually exclusive, so some combination may be used in deriving a prior distribution. Whichever source(s) and method(s) are chosen, it is important to remember that the same data should not be used twice. If the 2 | ICES Cooperative Research Report No. 328 plan is to use the data in the analysis for which the prior distribution is needed, then the same data cannot be used in formulating the prior. The techniques studied and proposed in this manual can be further elaborated and fine-tuned. New developments in technology can potentially be explored to find novel ways of forming prior distributions from different sources of information. Future research efforts should also be targeted at the philosophy and practices of model building based on existing prior information. Stock assessments that explicitly account for model uncertainty are still rare, and improving the methodology in this direction is an important avenue for future research. More research is also needed to make Bayesian analysis of non-parametric models more accessible in practice. Since Bayesian stock assessment models (like all other assessment models) are made from existing knowledge held by human beings, prior distributions for parameters and model structures may play a key role in the processes of collectively building and reviewing those models with stakeholders. Research on the theory and practice of these processes will be needed in the future.

Description: Increasing atmospheric CO2 concentrations are causing ocean acidification (OA), altering carbonate chemistry with consequences for marine organisms. Here we show that OA increases by 46–212% the production of phenolic compounds in phytoplankton grown under the elevated CO2 concentrations projected for the end of this century, compared with the ambient CO2 level. At the same time, mitochondrial respiration rate is enhanced under elevated CO2 concentrations by 130–160% in a single species or mixed phytoplankton assemblage. When fed with phytoplankton cells grown under OA, zooplankton assemblages have significantly higher phenolic compound content, by about 28–48%. The functional consequences of the increased accumulation of toxic phenolic compounds in primary and secondary producers have the potential to have profound consequences for marine ecosystem and seafood quality, with the possibility that fishery industries could be influenced as a result of progressive ocean changes

Description: Coexisting bacteria form various microbial communities in human body parts. In these ecosystems they interact in various ways and the properties of the interaction network can be related to the stability and functional diversity of the local bacterial community. In this study, we analyze the interaction network among bacterial OTUs in 11 locations of the human body. These belong to two major groups. One is the digestive system and the other is the female genital tract. In each local ecosystem we determine the key species, both the ones being in key positions in the interaction network and the ones that dominate by frequency. Beyond identifying the key players and discussing their biological relevance, we also quantify and compare the properties of the 11 networks. The interaction networks of the female genital system and the digestive system show totally different architecture. Both the topological properties and the identity of the key groups differ. Key groups represent four phyla of prokaryotes. Some groups appear in key positions in several locations, while others are assigned only to a single body part. The key groups of the digestive and the genital tracts are totally different.

Description: A sustainable global ocean observation system requires timely implementation of the framework for ocean observing. The recent Qingdao Global Ocean Summit highlighted the need for a more coherent institutional response to maintain an integrated ocean-observing system.

Description: Fossils of marine microorganisms such as planktic foraminifera are among the cornerstones of palaeoclimatological studies. It is often assumed that the proxies derived from their shells represent ocean conditions above the location where they were deposited. Planktic foraminifera, however, are carried by ocean currents and, depending on the life traits of the species, potentially incorporate distant ocean conditions. Here we use high-resolution ocean models to assess the footprint of planktic foraminifera and validate our method with proxy analyses from two locations. Results show that foraminifera, and thus recorded palaeoclimatic conditions, may originate from areas up to several thousands of kilometres away, reflecting an ocean state significantly different from the core site. In the eastern equatorial regions and the western boundary current extensions, the offset may reach 1.5 °C for species living for a month and 3.0 °C for longer-living species. Oceanic transport hence appears to be a crucial aspect in the interpretation of proxy signals.

Description: Microbiota provide their hosts with a range of beneficial services, including defense from external pathogens. However, host-associated microbial communities themselves can act as a source of opportunistic pathogens depending on the environment. Marine poikilotherms and their microbiota are strongly influenced by temperature, but experimental studies exploring how temperature affects the interactions between both parties are rare. To assess the effects of temperature, temperature stress and infection on diversity, composition and dynamics of the hemolymph microbiota of Pacific oysters (Crassostrea gigas), we conducted an experiment in a fully-crossed, three-factorial design, in which the temperature acclimated oysters (8 or 22 °C) were exposed to temperature stress and to experimental challenge with a virulent Vibrio sp. Strain. We monitored oyster survival and repeatedly collected hemolymph of dead and alive animals to determine the microbiome composition by 16s rRNA gene amplicon pyrosequencing. We found that the microbial dynamics and composition of communities in healthy animals (including infection survivors) were significantly affected by temperature and temperature stress, but not by infection. The response was mediated by changes in the incidence and abundance of operational taxonomic units (OTUs) and accompanied by little change at higher taxonomic levels, indicating dynamic stability of the hemolymph microbiome. Dead and moribund oysters, on the contrary, displayed signs of community structure disruption, characterized by very low diversity and proliferation of few OTUs. We can therefore link short-term responses of host-associated microbial communities to abiotic and biotic factors and assess the potential feedback between microbiota dynamics and host survival during disease.

Description: The useful energy services and energy density value of fossil carbon fuels could be retained for longer timescales into the future if their combustion is balanced by CO2 recapture and storage. We assess the global balance between fossil carbon supply and the sufficiency (size) and capability (technology, security) of candidate carbon stores. A hierarchy of value for extraction-to-storage pairings is proposed, which is augmented by classification of CO2 containment as temporary (〈1,000 yr) or permanent (〉100,000 yr). Using temporary stores is inefficient and defers an intergenerational problem. Permanent storage capacity is adequate to technically match current fossil fuel reserves. However, rates of storage creation cannot balance current and expected rates of fossil fuel extraction and CO2 consequences. Extraction of conventional natural gas is uniquely holistic because it creates the capacity to re-inject an equivalent tonnage of carbon for storage into the same reservoir and can re-use gas-extraction infrastructure for storage. By contrast, balancing the extraction of coal, oil, biomass and unconventional fossil fuels requires the engineering and validation of additional carbon storage. Such storage is, so far, unproven in sufficiency.

Description: Ocean islands, seamounts and volcanic ridges are thought to form above mantle plumes. Yet, this mechanism cannot explain many volcanic features on the Pacific Ocean floor and some might instead be caused by cracks in the oceanic crust linked to the reorganization of plate motions. A distinctive bend in the Hawaiian–Emperor volcanic chain has been linked to changes in the direction of motion of the Pacific Plate, movement of the Hawaiian plume, or a combination of both. However, these links are uncertain because there is no independent record that precisely dates tectonic events that affected the Pacific Plate. Here we analyse the geochemical characteristics of lava samples collected from the Musicians Ridges, lines of volcanic seamounts formed close to the Hawaiian–Emperor bend. We find that the geochemical signature of these lavas is unlike typical ocean island basalts and instead resembles mid-ocean ridge basalts. We infer that the seamounts are unrelated to mantle plume activity and instead formed in an extensional setting, due to deformation of the Pacific Plate. 40Ar/39Ar dating reveals that the Musicians Ridges formed during two time windows that bracket the time of formation of the Hawaiian–Emperor bend, 53–52 and 48–47 million years ago. We conclude that the Hawaiian–Emperor bend was formed by plate–mantle reorganization, potentially triggered by a series of subduction events at the Pacific Plate margins.

Description: Today’s predictions are tomorrow’s priors

Description: Carbon dioxide removal (CDR) from the atmosphere has been proposed as a measure for mitigating global warming and ocean acidification. To assess the extent to which CDR might eliminate the long-term consequences of anthropogenic CO2 emissions in the marine environment, we simulate the effect of two massive CDR interventions with CO2 extraction rates of 5 GtC yr(-1) and 25 GtC yr(-1), respectively, while CO2 emissions follow the extended RCP8.5 pathway. We falsify two hypotheses: the first being that CDR can restore pre-industrial conditions in the ocean by reducing the atmospheric CO2 concentration back to its pre-industrial level, and the second being that high CO2 emissions rates (RCP8.5) followed by CDR have long-term oceanic consequences that are similar to those of low emissions rates (RCP2.6). Focusing on pH, temperature and dissolved oxygen, we find that even after several centuries of CDR deployment, past CO2 emissions would leave a substantial legacy in the marine environment.

Description: Oxygen minimum zones are increasing, yet the effects of these zones on the genetic composition of marine fish stocks has been neglected. We assessed the combined effects of stock size and structure, and the prevailing oxygen situation, on Eastern Baltic cod (ICES SD25) genetic diversity. For this purpose, we used an integrative long-term otolith sample and data series (1995-2013) to (1) calculate the approximate number of females with surviving eggs in a given year, i.e., contributing to reproduction (n F), and (2) the annually resolved cohort mean allelic richness as proxy of genetic diversity, based on 12 microsatellite markers. Cohort mean allelic richness showed strong year-to-year fluctuations though no permanent decline. Importantly, it was highly correlated with n F, but with an unexpected 1.5 year time lag that may be an artefact of Eastern Baltic cod ageing problems. Our findings indicated that environmental pressure can effect rapid alterations in exploited fish stock genetic composition, and pointed to the importance of large females for Eastern Baltic cod reproduction during stagnation periods. Considering the importance of standing genetic variation for the evolutionary potential of populations, this is relevant for projections of the future state of cod stocks under global change.

Description: Cruise SO242/1 ran from 28 July to 25 August 2015 starting and ending in Guayaquil, Ecuador. In total, 40 scientists from five European countries took part in this cruise of the JPIO project ‚Ecological Aspects of Deep‐Sea Mining‘ to study the ecological long‐term impact of deep sea disturbances. The working area, the DISCOL area in the Peru Basin, was ploughed in 1989 and thoroughly studied in the years thereafter, the last cruise, SO106, happened in 1996. SO242/2 aimed at mapping the DISCOL Experimental Area (DEA) in great detail using ship‐based and AUV‐based hydroacoustic and optical methods. To see changes between differently disturbed areas and study the possible recovery of the ecosystem, biological sampling occurred with TV‐guided multi‐coring (MUC), box coring (BC) and epi‐benthic sledge tracks (EBS). Additional biological sampling for scavenging animals occurred with baited Amphipod‐Traps within and further outside the DEA. For geochemical sampling, multi‐, box and gravity coring (BC) was used. Two lander systems equipped with physical sensors such as ADCPs and CTDs were used for current measurements and to monitor sediment plume dispersal created by the EBS. Additional visual studies of the fauna distribution occurred with camera tows (OFOS). Five main sampling areas were selected, two within the DEA targeting heavily disturbed (ploughed) locations and three reference areas 3 to 4 nmi outside the DEA. All five areas had been sampled in the past and can be directly compared concerning ecological changes. Despite a four‐day break due to medical reasons the work program could almost be completed. Four of the working areas were at least sampled with five BCs and MUCs each, and one GC. Box coring could not be performed in the western reference area. In total, 5 CTDs, 27 MUCs, 25 BCs, 7 GCs, 8 EBSs, 5 Amphipod‐Traps, 6 lander deployments and 6 OFOS tracks were successfully undertaken and one thermistor mooring was deployed. In addition, 16 AUV dives clearly showed that plough marks are still well visible after 26 years. There is a slight sediment cover next to the plough tracks, but first analyses of the faunal distribution show that the sessile fauna has not yet recolonised the tracks. Stalked sponges, corals and anemones can be found outside the tracks but still within the DEA. Their distribution patterns inside the DEA do not vary clearly from those on reference sites. The Mn‐nodule distribution is not homogenous; there are areas inside the DEA that do not have nodules at the seafloor surface; they are typically linked to depressions that show low backscatter intensity in the AUV side scan sonar data pointing towards less dense sediment infill. In gravity cores, nodules could be recovered even in 9m sediment depth, finding several more or less intact nodules throughout the entire sediment column was common. Water current measurements show slow currents (max. 6cm/s) and a strong tide‐influenced current direction, whereas no general direction could be observed. Two ‘disturbance experiments’ demonstrated that sediment plumes can be monitored using high frequency ADCPs (1200 kHz). The disturbance by the EBS created a sediment plume that stayed close to the seafloor. First analyses of current trajectories showed that the sediment resettled rather quickly. It became clear that plume behaviour during large‐scale mining cannot be extrapolated from these small‐scale and short‐term experiments. In resume, cruise SO242/1 was very successful and research should continue in the DEA area, which is undoubtedly the best studied long‐term deep sea disturbance site in the ocean.

Description: Natural products have been a rich source of compounds for drug discovery. However, their use has diminished in the past two decades, in part because of technical barriers to screening natural products in high-throughput assays against molecular targets. Here, we review strategies for natural product screening that harness the recent technical advances that have reduced these barriers. We also assess the use of genomic and metabolomic approaches to augment traditional methods of studying natural products, and highlight recent examples of natural products in antimicrobial drug discovery and as inhibitors of protein–protein interactions. The growing appreciation of functional assays and phenotypic screens may further contribute to a revival of interest in natural products for drug discovery.

Description: Crossover recombination reshuffies genes and prevents errors in segregation tha't Iead to extra or missing chromosomes (aneuploidy) in human eggs, a major cause of pregnancy failure and congenital disorders. Here we generate genome-wide maps of cro~sovers and chromosome segregation patterns by recovering all three products of single female meioses. Genotyping 〉4 millioninformative SNPs from 23 complete meioses allowed us to map 2,032 maternal and 1,342 paternal crossovers and to infer the segregation patterns of 529 chromosome pairs. We uncover a new reverse chromosome segregation pattern in which both homologsseparate their sister chromatids at meiosis I; detect selection for higher recombination rates in the female germ line by the elimination of aneuploid embryos; and report chromosomal drive against non recombinant chromatids at meiosis II. Collectively, our findings show !hat recombination not only affects homolog segregation at meiosis I but also the fate of sister chromatids at meiosis II.

Description: Thiomicrospira species are ubiquitously found in various marine environments and appear particularly common in hydrothermal vent systems. Members of this lineage are commonly classified as sulfur-oxidizing chemolithoautotrophs. Although sequencing of Thiomicrospira crunogena's genome has revealed genes that encode enzymes for hydrogen uptake activity and for hydrogenase maturation and assembly, hydrogen uptake ability has so far not been reported for any Thiomicrospira species. We isolated a Thiomicrospira species (SP-41) from a deep sea hydrothermal vent and demonstrated that it can oxidize hydrogen. We show in vivo hydrogen consumption, hydrogen uptake activity in partially purified protein extracts and transcript abundance of hydrogenases during different growth stages. The ability of this strain to oxidize hydrogen opens up new perspectives with respect to the physiology of Thiomicrospira species that have been detected in hydrothermal vents and that have so far been exclusively associated with sulfur oxidation.

Description: The identification of an exchange of nutrients and signalling molecules between a planktonic alga and a bacterium demonstrates that targeted mutualistic interactions occur across domains of life in the oceans. See Letter p.98

Description: Particles in aquatic environments host distinct communities of microbes, yet the evolution of particlespecialized taxa and the extent to which specialized microbial metabolism is associated with particles is largely unexplored. Here, we investigate the hypothesis that a widely distributed and uncultivated microbial group - the marine group II euryarchaea (MGII) - interacts with living and detrital particulate organic matter (POM) in the euphotic zone of the central California Current System. Using fluorescent in situ hybridization, we verified the association of euryarchaea with POM. We further quantified the abundance and distribution of MGII 16S ribosomal RNA genes in size-fractionated seawater samples and compared MGII functional capacity in metagenomes from the same fractions. The abundance of MGII in free-living and 〈3 μm fractions decreased with increasing distance from the coast, whereas MGII abundance in the 0.8-3 lm fraction remained constant. At several offshore sites, MGII abundance was highest in particle fractions, indicating that particle-attached MGII can outnumber free-living MGII under oligotrophic conditions. Compared with free-living MGII, the genome content of MGII in particleassociated fractions exhibits an increased capacity for surface adhesion, transcriptional regulation and catabolism of high molecular weight substrates. Moreover, MGII populations in POM fractions are phylogenetically distinct from and more diverse than free-living MGII. Eukaryotic phytoplankton additions stimulated MGII growth in bottle incubations, providing the first MGII net growth rate measurements. These ranged from 0.47 to 0.54 d-1. However, MGII were not recovered in wholegenome amplifications of flow-sorted picoeukaryotic phytoplankton and heterotrophic nanoflagellates, suggesting that MGII in particle fractions are not physically attached to living POM. Collectively, our results support a linkage between MGII ecophysiology and POM, implying that marine archaea have a role in elemental cycling through interactions with particles. © 2015 International Society for Microbial Ecology. All rights reserved.

Description: Algae with secondary plastids of a red algal origin, such as ochrophytes (photosynthetic stramenopiles), are diverse and ecologically important, yet their evolutionary history remains controversial. We sequenced plastid genomes of two ochrophytes, Ochromonas sp. CCMP1393 (Chrysophyceae) and Trachydiscus minutus (Eustigmatophyceae). A shared split of the clpC gene as well as phylogenomic analyses of concatenated protein sequences demonstrated that chrysophytes and eustigmatophytes form a clade, the Limnista, exhibiting an unexpectedly elevated rate of plastid gene evolution. Our analyses also indicate that the root of the ochrophyte phylogeny falls between the recently redefined Khakista and Phaeista assemblages. Taking advantage of the expanded sampling of plastid genome sequences, we revisited the phylogenetic position of the plastid of Vitrella brassicaformis, a member of Alveolata with the least derived plastid genome known for the whole group. The results varied depending on the dataset and phylogenetic method employed, but suggested that the Vitrella plastids emerged from a deep ochrophyte lineage rather than being derived vertically from a hypothetical plastid-bearing common ancestor of alveolates and stramenopiles. Thus, we hypothesize that the plastid in Vitrella, and potentially in other alveolates, may have been acquired by an endosymbiosis of an early ochrophyte.