ALBERT

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: The knowledge of the phase behavior of carbon dioxide (CO2)-rich mixtures is a key factor to understand the chemistry and migration of natural volcanic CO2 seeps in the marine environment, as well as to develop engineering processes for CO2 sequestration coupled to methane (CH4) production from gas hydrate deposits. In both cases, it is important to gain insights into the interactions of the CO2-rich phase—liquid or gas—with the aqueous medium (H2O) in the pore space below the seafloor or in the ocean. Thus, the CH4-CO2 binary and CH4-CO2-H2O ternary mixtures were investigated at relevant pressure and temperature conditions. The solubility of CH4 in liquid CO2 (vapor-liquid equilibrium) was determined in laboratory experiments and then modelled with the Soave–Redlich–Kwong equation of state (EoS) consisting of an optimized binary interaction parameter kij(CH4-CO2) = 1.32 × 10−3 × T − 0.251 describing the non-ideality of the mixture. The hydrate-liquid-liquid equilibrium (HLLE) was measured in addition to the composition of the CO2-rich fluid phase in the presence of H2O. In contrast to the behavior in the presence of vapor, gas hydrates become more stable when increasing the CH4 content, and the relative proportion of CH4 to CO2 decreases in the CO2-rich phase after gas hydrate formation.

Description: In the frame of studies on secondary metabolites produced by fungi from deep-sea environments we have investigated inhibitors of enzymes playing key roles in signaling cascades of biochemical pathways relevant for the treatment of diseases. Here we report on a new inhibitor of the human protein tyrosine phosphatase 1B (PTP1B), a target in the signaling pathway of insulin. A new asperentin analog is produced by an Aspergillus sydowii strain isolated from the sediment of the deep Mediterranean Sea. Asperentin B (1) contains an additional phenolic hydroxy function at C-6 and exhibits an IC50 value against PTP1B of 2 μM in vitro, which is six times stronger than the positive control, suramin. Interestingly, asperentin (2) did not show any inhibition of this enzymatic activity. Asperentin B (1) is discussed as possible therapeutic agents for type 2 diabetes and sleeping sickness.

Description: A new cyclic dipeptide, petrocidin A (1), along with three known compounds—2,3dihydroxybenzoic acid (2), 2,3-dihydroxybenzamide (3), and maltol (4)—were isolated from the solid culture of Streptomyces sp. SBT348. The strain Streptomyces sp. SBT348 had been prioritized in a strain collection of 64 sponge-associated actinomycetes based on its distinct metabolomic profile using liquid chromatography/high-resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR). The absolute configuration of all α-amino acids was determined by HPLC analysis after derivatization with Marfey’s reagent and comparison with commercially available reference amino acids. Structure elucidation was pursued in the presented study by mass spectrometry and NMR spectral data. Petrocidin A (1) and 2,3-dihydroxybenzamide (3) exhibited significant cytotoxicity towards the human promyelocytic HL-60 and the human colon adenocarcinoma HT-29 cell lines. These results demonstrated the potential of sponge-associated actinomycetes for the discovery of novel and pharmacologically active natural products.

Description: As part of an international research project, the marine fungal strain collection of the Helmholtz Centre for Ocean Research (GEOMAR) research centre was analysed for secondary metabolite profiles associated with anticancer activity. Strain MF458 was identified as Tolypocladium geodes, by internal transcribed spacer region (ITS) sequence similarity and its natural product production profile. By using five different media in two conditions and two time points, we were able to identify eight natural products produced by MF458. As well as cyclosporin A (1), efrapeptin D (2), pyridoxatin (3), terricolin A (4), malettinins B and E (5 and 6), and tolypocladenols A1/A2 (8), we identified a new secondary metabolite which we termed tolypocladenol C (7). All compounds were analysed for their anticancer potential using a selection of the NCI60 cancer cell line panel, with malettinins B and E (5 and 6) being the most promising candidates. In order to obtain sufficient quantities of these compounds to start preclinical development, their production was transferred from a static flask culture to a stirred tank reactor, and fermentation medium development resulted in a nearly eight-fold increase in compound production. The strain MF458 is therefore a producer of a number of interesting and new secondary metabolites and their production levels can be readily improved to achieve higher yields

Description: This study explores non-metric multidimensional scaling (nMDS) as a tool for investigating parasites as indicators of the elasmobranch biology. An attractive feature of nMDS is its ability to allow assemblage-level parasite data to be simultaneously applied to questions of host biology. This method was examined using the tapeworm order Trypanorhyncha Diesing, 1863, which is known to be transmitted among their hosts through the marine food web (via predation), can unambiguously be identified in the intermediate and final hosts, and has the potential as an indicator of the host feeding biology. Our analyses focused on trypanorhynch assemblages in elasmobranchs as definitive hosts. The relationships between trypanorhynch assemblages and the depth, feeding ecology, habitat, and phylogeny for all sharks were complex, but we found that depth distribution, diet composition and habitat type were the major influencing factors. Several species of sharks showed different characters than known from their descriptions that could be attributed to the change of shark behavior or the trypanorhynch host path. The relationship between the trypanorhynch assemblage and factors for carcharhiniform species alone was more robust than for all sharks. In the carcharhiniform analysis, the relationship between habitat type and trypanorhynch assemblage was most remarkable. Overlapping host ecology was evident even in phylogenetically-distant related hosts.

Description: Mit der Neuauflage der Deutschen Nachhaltigkeitsstrategie hat die Bundesregierung die Wissenschaft zur Bildung einer Plattform aufgefordert, die systematisch in die Steuerungs-, Dialog- und Umsetzungsprozesse der Agenda 2030 und somit die neue Nachhaltigkeitsarchitektur eingebunden ist. Träger der Plattform sind die internationalen wissenschaftlichen Netzwerke Sustainable Development Solutions Network Germany (SDSN Germany), das Deutsche Komitee für Nachhaltigkeitsforschung in Future Earth (DKN Future Earth) sowie das Institute for Advanced Sustainability Studies (IASS), das zusätzlich die Geschäftsstelle der Wissenschaftsplattform beherbergt. Die inhaltliche und operative Ausgestaltung der Arbeit der Plattform liegt in der Verantwortung des Lenkungskreises aus derzeit 26 Mitgliedern aus Wissenschaft, Wirtschaft und organisierter Zivilgesellschaft. Der Lenkungskreis formuliert das Arbeitsprogramm und initiiert Arbeitsprozesse sowie die Vernetzung mit weiteren Akteuren aus Wissenschaft, Politik, Wirtschaft und Zivilgesellschaft, um eine effektive wie auch repräsentative und international verankerte Plattform aufzubauen. Die Plattform wird auf Seiten der Bundesregierung von einem für alle Ressorts offenen Kreis begleitet, in dem zurzeit BMBF, BMUB, BMZ, BMEL sowie Bundeskanzleramt mitwirken. Die Wissenschaftsplattform Nachhaltigkeit 2030 wurde am 8. Mai 2017 mit der konstituierenden Sitzung ihres Lenkungskreises etabliert und im Rahmen des 13. BMBF-Forums für Nachhaltigkeit am 9. Mai 2017 der Öffentlichkeit vorgestellt.

Description: Through the present report, we would like to share with you theinspiring outcomes of our joint experience at the Global Soil Week2017, and offer you an opportunity to reflect on the high potential ofpreparatory events to the HLPF, and of using its thematic reviews asmeans to achieve an integrated implementation of the SDGs.

Description: This document includes the main policy outcomes of the Global Soil Week 2017 by introducing 1) the principles and methods utilized, 2) the five key policy messages discussed in plenary with the participants and 3) considerations from the discussions at the Global Soil Week supporting the five key policy messages. We respectfully submit the messages below, for consideration by the High Level Political Forum (HLPF), and reinforce our commitment to contribute to strengthening the work and role of the HLPF. We also stand ready to work together with Member States aiming to strengthen the emphasis on soil- and land-related issues in their National Voluntary Reviews and also with platforms aiming to conduct similar reviews.

Description: Seit 2012 beschäftigt sich das Forschungsprojekt ClimPol (Climate Change and Air Pollution)am Institute for Advanced Sustainability Studies (IASS) in Potsdam mit dem Zusammenhängenzwischen Klimawandel und Luftverschmutzung. Mit unseren wissenschaftlichen Untersuchungenwollen wir diese Zusammenhänge besser verstehen. Wir engagieren uns aber auchan der Schnittstelle von Wissenschaft und Politik, indem wir koordinierte und effektiveMaßnahmen für Klimaschutz und bessere Luftqualität prüfen.

Description: The German energy transition (Energiewende) is the subject of intensive research, and thankfully so. We now have reliable estimates relating to the required deployment of technology, the costs for end consumers and society, and the expected consequences for health and the environment. It has been firmly established just how much CO2 we have already saved with the energy transition, and what is required in order to reduce CO2 emissions even further. There is also a range of scientific studies on the impact of the expansion of renewable energies on nature conservation and species protection. However, one question has received little academic attention to date: How does the energy transition affect society? It is astonishing that we know so little about this. After all, experts have long been agreed on the fact that sustainability does not just have an economic and ecological dimension, but also a social one. It is essential that we consider the social impact to the same extent as the economic or ecological effects. So it is high time to give the question of social sustainability a solid empirical base. The Institute for Advanced Sustainability Studies (IASS), together with the RWI – Leibniz Institute for Economic Research, conducted a panel survey of more than 7,500 households. Now, with the Social Sustainability Barometer for the German Energiewende 2017, we present the results for the first time.

Description: KEY MESSAGES1. Without strategic investment in soil rehabilitation and protectionpoor and food insecure households will be left behind and globalagendas will not be achieved! Targeting is of the essence.2. Public investment in soil protection and rehabilitation must beincreased; the private sector has little incentive in investing in soilrehabilitation by food insecure households.3. Cross-sectorial coordination is pivotal to create the right incentivesand to ensure that structural hindrances to SLM are addressedsystematically.4. Technologies for protecting and rehabilitating land and soil at plotand farm levels are well known but are seldom applied at largerscales. Successful adoption – and adaptation – at scale is conditionalon locally owned and driven processes.5. Supportive tenure systems and responsive agricultural advisoryservices are essential preconditions for achieving soil protection andrehabilitation at scale. They must be gender and youth sensitive, andcreate the necessary incentives to protect the soils.

Description: Klimawandel, Hungersnöte, Weltwirtschaftskrisen: Viele Risiken sind heute systemisch, vernetzt und nicht über geläufige Ursache-Wirkungs-Modelle erklärbar. Natürliche, technische und sozioökonomische Prozesse interagieren mit gesellschaftlichen. Die Risikoforschung braucht einen systemischen Blick.

Description: Die Energiewende wird intensiv beforscht – glücklicherweise. Wir haben inzwischen zuverlässige Abschätzungen zu Fragen des notwendigen Technikeinsatzes, der Kosten für Endverbraucher und Gesellschaft und der zu erwartenden Konsequenzen für Umwelt und Gesundheit. Es ist gut erfasst, wie viel CO2 wir mit der Energiewende bereits eingespart haben und was geboten ist, um die CO2-Emissionen weiter zu reduzieren. Auch über die Auswirkungen des Ausbaus der erneuerbaren Energien auf den Natur- und Artenschutz gibt es eine Reihe von wissenschaftlichen Studien. Es gibt aber eine Frage, die bislang wenig wissenschaftlich beleuchtet wurde: Was macht die Energiewende mit der Gesellschaft? Dass wir hierzu sehr wenig wissen, verblüfft. Denn schon lange herrscht im fachlichen Diskurs Einigung vor: Nachhaltigkeit hat nicht nur eine ökonomische und eine ökologische, sondern auch eine soziale Dimension. Daher gilt es, über die gesellschaftlichen Wirkungen der Energiewende genauso gut Bescheid zu wissen wie über die wirtschaftlichen oder ökologischen. Höchste Zeit also, der Frage nach der sozialen Nachhaltigkeit eine solide empirische Basis zu geben. Das Institut für transformative Nachhaltigkeitsforschung (IASS) hat gemeinsam mit dem RWI-Leibniz-Institut für Wirtschaftsforschung über 7.500 Haushalte in einer Panel Untersuchung befragen lassen. Mit dem „Sozialen Nachhaltigkeitsbarometer der Energiewende 2017“ legen wir nun erstmalig die Ergebnisse vor.

Description: In dieser Broschüre finden Sie die wichtigsten Zahlen und Fakten zum IASS auf einen Blick. Außerdem eine Auswahl an Zeitschriftenartikeln und Publikationen der Schriftenreihe aus den Jahren 2014 bis 2016.

Description: Fait réjouissant, la transition énergétique allemande, ou Energiewende, fait l’objet d’intenses activités de recherche. Nous disposons à présent d’estimations fiables sur les technologies, les coûts pour les consommateurs finaux et la société, et les conséquences auxquelles on peut s’attendre pour l’environnement et la santé. Nous savons combien les émissions de CO2 ont déjà été réduites grâce à la transition énergétique, et comment procéder pour les réduire encore davantage. Il existe également un certain nombre d’études scientifiques traitant des effets de l’expansion des énergies renouvelables sur la protection de la nature et des espèces. Une question reste cependant peu examinée : quells sont les effets de la transition énergétique sur la société? Il est surprenant que nous en sachions si peu sur ce sujet. Les spécialistes s’accordent depuis longtemps à dire que les dimensions du développement durable ne sont pas seulement économiques et écologiques, mais aussi sociales. Il est donc tout aussi important d’analyser les effets de la transition énergétique sur la société que sur l’économie ou l’écologie. Il est grand temps de donner un fondement empirique solide à la question de la durabilité sociale. L’Institute for Advanced Sustainability Studies (IASS) a mené, avec l’Institut RWI-Leibniz pour la recherche économique, une étude auprès de plus de 7 500 ménages. Avec le « Baromètre de la durabilité sociale de la transition énergétique allemande 2017 », nous présentons aujourd’hui les résultats pour la première fois.

Description: This brochure presents the most important facts and figures on the IASS as well as a selection of journal articles and publications from the IASS Series from 2014 to 2016.

Description: The Science Platform at a glance In the new version of the German Sustainable Development Strategy, the Federal Government called on the scientific community to create a platform that is systematically involved in the steering, dialogue and implementation processes of the 2030 Agenda and its sustainability architecture. In response to this, the Science Platform Sustainability 2030 was launched on 8 May 2017 and was presented to the public one day later at the 13th BMBF Forum for Sustainability. The platform is supported by three organising institutions: the Sustainable Development Solutions Network Germany (SDSN Germany), the German Committee Future Earth (DKN Future Earth) and the Institute for Advanced Sustainability Studies (IASS), which houses the platform’s secretariat. A steering committee consisting of 26 members from science, the business community, and civil society is responsible for the platform’s activities and operative management. The committee also links the platform with other actors from science, politics, economics and civil society in an effort to build an effective, representative and internationally anchored platform. Additional support is provided by a circle of government agencies (open to all federal ministries) – currently including the BMBF, the BMUB, the BMZ, the BMEL and the Federal Chancellery.

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 presence of sea-ice leads represents a key feature of the Arctic sea ice cover. Leads promote the flux of sensible and latent heat from the ocean to the cold winter atmosphere and are thereby crucial for air-sea-ice-ocean interactions. We here apply a binary segmentation procedure to identify leads from MODIS thermal infrared imagery on a daily time scale. The method separates identified leads into two uncertainty categories, with the high uncertainty being attributed to artifacts that arise from warm signatures of unrecognized clouds. Based on the obtained lead detections, we compute quasi-daily pan-Arctic lead maps for the months of January to April, 2003–2015. Our results highlight the marginal ice zone in the Fram Strait and Barents Sea as the primary region for lead activity. The spatial distribution of the average pan-Arctic lead frequencies reveals, moreover, distinct patterns of predominant fracture zones in the Beaufort Sea and along the shelf-breaks, mainly in the Siberian sector of the Arctic Ocean as well as the well-known polynya and fast-ice locations. Additionally, a substantial inter-annual variability of lead occurrences in the Arctic is indicated.

Description: Sharing and secondary analysis of data have become increasingly important for research. Especially in geography, the collection of digital data has grown due to technological changes. Responsible handling and proper documentation of research data have therefore become essential for funders, publishers and higher education institutions. To achieve this goal, universities offer support and training in research data management. This article presents the experiences of a pilot workshop in research data management, especially for geographers. A discipline-specific approach to research data management training is recommended. The focus of this approach increases researchers’ interest and allows for more specific guidance. The instructors identified problems and challenges of research data management for geographers. In regards to training, the communication of benefits and reaching the target groups seem to be the biggest challenges. Consequently, better incentive structures as well as communication channels have to be established.

Description: Underwater photogrammetry and in particular systematic visual surveys of the deep sea are by far less developed than similar techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), and the limitations of localization technologies (no GPS). The absence of natural light complicates energy budget considerations for deep diving flash-equipped drones. Refraction effects influence geometric image formation considerations with respect to field of view and focus, while attenuation and scattering degrade the radiometric image quality and limit the effective visibility. As an improvement on the stated issues, we present an AUV-based optical system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare it to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent deployment with 90,000 mapped square meters of deep ocean floor.

Description: Filamentous fungi are well known for their capability of producing antibiotic natural products. Recent studies have demonstrated the potential of antimicrobials with vast chemodiversity from marine fungi. Development of such natural products into lead compounds requires sustainable supply. Marine biotechnology can significantly contribute to the production of new antibiotics at various levels of the process chain including discovery, production, downstream processing, and lead development. However, the number of biotechnological processes described for large-scale production from marine fungi is far from the sum of the newly-discovered natural antibiotics. Methods and technologies applied in marine fungal biotechnology largely derive from analogous terrestrial processes and rarely reflect the specific demands of the marine fungi. The current developments in metabolic engineering and marine microbiology are not yet transferred into processes, but offer numerous options for improvement of production processes and establishment of new process chains. This review summarises the current state in biotechnological production of marine fungal antibiotics and points out the enormous potential of biotechnology in all stages of the discovery-to-development pipeline. At the same time, the literature survey reveals that more biotechnology transfer and method developments are needed for a sustainable and innovative production of marine fungal antibiotics.

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: During the past decades, tremendous advances have been made in the possibilities to study the diversity of microbial communities in the environment. The development of methods to study these communities on the basis of 16S rRNA gene sequences analysis was a first step into the molecular analysis of environmental communities and the study of biodiversity in natural habitats. A new dimension in this field was reached with the introduction of functional genes of ecological importance and the establishment of genetic tools to study the diversity of functional microbial groups and their responses to environmental factors. Functional gene approaches are excellent tools to study the diversity of a particular function and to demonstrate changes in the composition of prokaryote communities contributing to this function. The phylogeny of many functional genes largely correlates with that of the 16S rRNA gene, and microbial species may be identified on the basis of functional gene sequences. Functional genes are perfectly suited to link culture-based microbiological work with environmental molecular genetic studies. In this review, the development of functional gene studies in environmental microbiology is highlighted with examples of genes relevant for important ecophysiological functions. Examples are presented for bacterial photosynthesis and two types of anoxygenic phototrophic bacteria, with genes of the Fenna-Matthews-Olson-protein (fmoA) as target for the green sulfur bacteria and of two reaction center proteins (pufLM) for the phototrophic purple bacteria, with genes of adenosine-5′phosphosulfate (APS) reductase (aprA), sulfate thioesterase (soxB) and dissimilatory sulfite reductase (dsrAB) for sulfur oxidizing and sulfate reducing bacteria, with genes of ammonia monooxygenase (amoA) for nitrifying/ammonia-oxidizing bacteria, with genes of particulate nitrate reductase and nitrite reductases (narH/G, nirS, nirK) for denitrifying bacteria and with genes of methane monooxygenase (pmoA) for methane oxidizing bacteria.

Description: The properties and the production of new metabolites from the fungal strain LF657 isolated from the Herodotes Deep (2800 m depth) in the Mediterranean Sea are reported in this study. The new isolate was identified as Biscogniauxia mediterranea based on ITS1-5.8S-ITS2 and 28S rRNA gene sequences. A new isopyrrolonaphthoquinone with inhibitory activity against glycogen synthase kinase (GSK-3β) was isolated from this fungus. This is the first report of this class of compounds from a fungus isolated from a deep-sea sediment, as well as from a Biscogniauxia species.

Description: European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis total precipitation estimates are validated against ten years of in situ precipitation measurements onboard of ships over the Baltic Sea. A statistical analysis for binary forecasts and mean rain rates derived from all data show a good agreement with observations. However, a closer look reveals an underestimation of ERA-Interim total precipitation in spring and an overestimation in autumn, obviously related to stability. Deriving stability and evaporation by a bulk flux scheme it could be shown, in fact, that ERA-Interim underestimates precipitation for conditions with low evaporation and strongly overestimates it for conditions with high evaporation. Since ERA-Interim surface fields become too dry with increasing evaporation compared to independent synoptic ship observations, uncertainties in the ECMWF convection scheme may possibly cause these biases in seasonal precipitation.

Description: Marine fungi represent a huge potential for new natural products and an increased number of new metabolites have become known over the past years, while much of the hidden potential still needs to be uncovered. Representative examples of biodiversity studies of marine fungi and of natural products from a diverse selection of marine fungi from the author's lab are highlighting important aspects of this research. If one considers the huge phylogenetic diversity of marine fungi and their almost ubiquitous distribution, and realizes that most of the published work on secondary metabolites of marine fungi has focused on just a few genera, strictly speaking Penicillium, Aspergillus and maybe also Fusarium and Cladosporium, the diversity of marine fungi is not adequately represented in investigations on their secondary metabolites and the less studied species deserve special attention. In addition to results on recently discovered new secondary metabolites of Penicillium species, the diversity of fungi in selected marine habitats is highlighted and examples of groups of secondary metabolites produced by representatives of a variety of different genera and their bioactivities are presented. Special focus is given to the production of groups of derivatives of metabolites by the fungi and to significant differences in biological activities due to small structural changes.

Description: Lake Urmia, the second largest saline Lake on earth and a highly endangered ecosystem, is on the brink of a serious environmental disaster similar to the catastrophic death of the Aral Sea. Progressive drying has been observed during the last decade, causing dramatic changes to Lake Urmia’s surface and its regional water supplies. The present study aims to improve monitoring of spatiotemporal changes of Lake Urmia in the period 1975–2015 using the multi-temporal satellite altimetry and Landsat (5-TM, 7-ETM+ and 8-OLI) images. In order to demonstrate the impacts of climate change and human pressure on the variations in surface extent and water level, Lake Sevan and Van Lake with different characteristics were studied along with the Urmia Lake. Normalized Difference Water Index-Principal Components Index (NDWI-PCs), Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI), Normalized Difference Moisture Index (NDMI), Water Ratio Index (WRI), Normalized Difference Vegetation Index (NDVI), Automated Water Extraction Index (AWEI), and MultiLayer Perceptron Neural Networks (MLP NNs) classifier were investigated for the extraction of surface water from Landsat data. The presented results revealed that MLP NNs has a better performance in the cases where the other models generate poor accuracy. The results show that the area of Lake Sevan and Van Lake have increased while the area of Lake Urmia has decreased by ~65.23% in the past decades, far more than previously reported (~25% to 50%). Urmia Lake’s shoreline has been receding severely between 2010 and 2015 with no sign of recovery, which has been partly blamed on prolonged droughts, aggressive regional water resources development plans, intensive agricultural activities, and anthropogenic changes to the system. The results also indicated that (among the proposed factors) changes in inflows due to overuse of surface water resources and constructing dams (mostly during 1995–2005) are the main reasons for Urmia Lake’s shoreline receding. The model presented in this manuscript can be used by managers as a decision support system to find the effects of building new dams or other infrastructures

Description: The glycogen-synthase-kinase 3 (GSK-3) is an important target in drug discovery. This enzyme is involved in the signaling pathways of type 2 diabetes, neurological disorders, cancer, and other diseases. Therefore, inhibitors of GSK-3 are promising drug candidates for the treatment of a broad range of diseases. Here we report pannorin (1), alternariol (2), and alternariol-9-methylether (3) to be promising inhibitors of the isoform GSK-3β showing sub-μM IC50 values. The in vitro inhibition is in the range of the known highly active GSK-3β inhibitor TDZD-8. Compounds 1–3 have a highly oxygenated benzocoumarin core structure in common, which suggests that this may be a new structural feature for efficient GSK-3β inhibition

Description: Ocean Acidification (OA) represents a major field of research and increased efforts are being made to elucidate its repercussions on biota. Species survival is ensured by successful reproduction, which may be threatened under detrimental environmental conditions, such as OA acting in synergy with other climate change related stressors. Achieving successful gametogenesis, fertilization, and the development of larvae into healthy juveniles and adults is crucial for the perpetuation of species and, thus, ecosystems’ functionality. The considerable vulnerability of the abovementioned developmental stages to the adverse conditions that future OA may impose has been shown in many species, including sea urchins which are commonly used due to the feasibility of their maintenance in captivity and the great amount of gametes that a mature adult is able to produce. In the present review, the latest knowledge about the impact of OA on various stages of the life cycle of sea urchins is summarized with remarks on the possible impact of other stressors. The cellular physiology of the gametes before, at fertilization and, at early development, is extensively described with a focus on the complex enzymatic machinery and the intracellular pH (pHi) and Ca2+ homeostasis for their vulnerability when facing adverse conditions such as acidification, temperature variations, or hypoxia.

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: Carbon dioxide (CO2) is a fundamental component of all life on Earth. Due to the considerable increase in emissions, particularly industrial emissions, CO2has, however, become a waste product and greenhouse gas damaging to the climate and, consequently, a threat to both humanity and nature. For almost 50years, chemical research has been pursuing the idea of making the CO2 molecule useful as a raw material(Aresta and Dibenedetto 2010). Within the context of the oil crises of the 1970s, and contingent on the currentneed for climate protection, there has been a rise in global interest in the research and development oftechnologies which could make CO2 useful as a source of carbon. Several regions in Europe, but also in North America and Asia have started sponsorship programmes to support the development of such technologies (BMBF 2014, Climate-KIC 2014, U.S. Department of Energy [DOE] n.d.).The goal of these efforts is to integrate this climatedamaging gas in extremely diverse industrial productionprocesses as a raw material. The use of CO2 would not only allow for the production of useful raw materials and products, such technologies could alsoemulate a natural carbon cycle (Peters et al. 2011). At the same time, they have the potential to reduce the consumption of other fossil resources and, in so doing, they might not only contribute to the extension of the resource base, but also reduce missionswhilst providing protection for natural resources (von der Assen et al. 2013). Technological breakthroughs and advancements are currently observedin carbon capture technologies in the catalysis and transformation of CO2 (Aresta 2010, Mikkelsen et al. 2010, Peters et al. 2011, Styring et al. 2011, Wilcox 2012, Smit et al. 2014, Klankermayer and Leitner 2015), and the first innovative CO2-based productsare already coming onto the markets.

Description: Kohlenstoffdioxid (CO2) ist ein Grundbaustein allen Lebens auf der Erde. Mittlerweile ist CO2 jedochdurch den starken Anstieg vor allem industrieller Emissionen als klimaschädlicher Abfall und Treibhausgas zu einer Bedrohung für Menschheit und Natur geworden. Bereits seit fast 50 Jahren verfolgt die chemische Forschung die Idee, das Molekül CO2 als Rohstoff nutzbar zu machen (Aresta & Dibenedetto 2010). Im Kontext der Ölkrisen in den 1970er-Jahren und bedingt durch die Erfordernisse des aktuellen Klimaschutzes stieg weltweit das Interesse an der Erforschung und Entwicklung von Technologien, die CO2 als Kohlenstoffquelle nutzen könnten.Etliche Regionen in Europa, aber auch in Nordamerika und Asien haben Förderprogramme ins Leben gerufen, die solche Technologieentwicklungen unterstützen (BMBF 2013, Climate-KIC 2014, US DOE o. D.-b).Das Ziel dieser Bemühungen ist es, das klimaschädliche Gas als Rohstoff in ganz unterschiedliche industrielleProduktionsprozesse einzubinden. Hiermit könnten mithilfe von CO2 nicht nur nützliche Grundstoffe und Produkte hergestellt werden. Vielmehr imitieren diese Technologien auch einen natürlichen Kohlenstoffkreislauf (Peters et al. 2011). Gleichzeitighaben sie das Potenzial, den Verbrauch anderer fossiler Ressourcen zu verringern und somit möglicherweisenicht nur zur Erweiterung der Rohstoffbasis, sondern auch zur Schonung natürlicher Ressourcenund zur Emissionsverminderung beizutragen (von der Assen, Jung & Bardow 2013). Technologische Durchbrüche und Fortschritte sind derzeit sowohl in den Abscheidungstechnologien als auch in der Katalyse und Umwandlung von CO2 zu beobachten (Aresta 2010, Klankermayer & Leitner 2015, Mikkelsen, Jorgensen& Krebs 2010, Peters et al. 2011, Smit, Park & Gadikota 2014, Styring et al. 2011, Wilcox 2012). Erste neuartige CO2-basierte Produkte erreichen aktuelldie Märkte.

Description: This IASS study considers the potential of the G20 to shape a global transition to sustainable energy, urgentlyneeded in order to achieve the UN’s climate and sustainability goals. The G20, a group of major emerging andindustrialised economies, is a high-level political forum that brings together a heterogeneous set of members.The Group carries great weight in international energy governance, and accounts for 80 percent of the world’s totalprimary energy consumption and 82 percent of global energy-related CO2 emissions. Thus, decisions and actions ofthe G20 and its members have the capacity to significantly impact global energy systems.The study analyses the energy sector developments of 14 G20 members (Argentina, Brazil, China, European Union,France, Germany, India, Indonesia, Japan, Russia, Saudi Arabia, South Africa, Turkey and the United States).Short case studies trace major trends and policy initiatives in the countries and identify both potential conflictsof interest and existing common ground within the G20. Each study offers an assessment of potential impulsesoriginating from the respective case, and how these might help foster international cooperation for advancing aglobal energy transition.

Description: Table of Contents1. Introduction and Main Insights from the Study - Sybille Roehrkasten, Sonja Thielges and Rainer Quitzow http://publications.iass-potsdam.de/pubman/item/escidoc:19069032. The G20 and its Role in Global Energy Governance - Sybille Roehrkasten and Kirsten Westphal http://publications.iass-potsdam.de/pubman/item/escidoc:19069073. Argentina: From an Energy Stalemate Towards Shale Gas Expansion and Creating a Renewables Market - Moïra Jimeno http://publications.iass-potsdam.de/pubman/item/escidoc:19069104. Brazil: Long Tradition of Renewables-Based Energy Supply and Ethanol Diplomacy - Sybille Roehrkasten http://publications.iass-potsdam.de/pubman/item/escidoc:19069135. China: Emerging Global Power in Clean Energy? - Rainer Quitzow http://publications.iass-potsdam.de/pubman/item/escidoc:19088896. The EU: In the Midst of Crisis – Downgraded SustainableEnergy Ambitions - Kirsten Westphal http://publications.iass-potsdam.de/pubman/item/escidoc:19108887. France: Reducing Nuclear Dominance and Promoting a Low-Carbon Energy System - Carole Mathieu http://publications.iass-potsdam.de/pubman/item/escidoc:19108918. Germany: Promoting an Energiewende Domestically and Globally - Sybille Roehrkasten and Karoline Steinbacher http://publications.iass-potsdam.de/pubman/item/escidoc:19108959. India: Meeting Energy Needs for Development While Addressing Climate Change - Madhura Joshi and Radhika Khosla http://publications.iass-potsdam.de/pubman/item/escidoc:191089710. Indonesia: A Long Way to Low-Carbon Development - Jens Marquardt http://publications.iass-potsdam.de/pubman/item/escidoc:191090011. Japan: Dominated by Fukushima and Tackling Hard Problemsin Decarbonisation - Llewelyn Hughes http://publications.iass-potsdam.de/pubman/item/escidoc:191090312. Russia: A Gas Superpower Striving for Nuclear Expansion and Starting to Support Renewables - Alexander Gusev http://publications.iass-potsdam.de/pubman/item/escidoc:191090713. Saudi Arabia: Oil as a Burden in the Struggle for Energy Diversification - Sebastian Sons http://publications.iass-potsdam.de/pubman/item/escidoc:191091014. South Africa: Carbon-Intensive Economy and a Regional Renewable Energy Frontrunner - Agathe Maupin http://publications.iass-potsdam.de/pubman/item/escidoc:191091315. Turkey: Great Potential, Missing Will - Jörn Richert http://publications.iass-potsdam.de/pubman/item/escidoc:191091616. The United States: Domestic Transitions and International Leadership Towards Low-Carbon Energy - Karoline Steinbacher http://publications.iass-potsdam.de/pubman/item/escidoc:1910919

Description: Der Beteiligung von Bürgerinnen und Bürgern, Gemeinden und Städten an der Gestaltung undUmsetzung gesellschaftlicher Großprojekte wie der Energiewende wird vielerorts eine großeBedeutung beigemessen. Dies zeigt sich besonders da, wo die deutlich dezentraleren Strukturen desneuen Energiesystems die Planung von Windenergie- und Biomasseanlagen oder auch neuenÜbertragungsnetzen erforderlich machen. Bürgerbeteiligung wird hierfür als ein Modus gesehen, umKonflikte um Infrastrukturprojekte zu lösen und Akzeptanz herzustellen. Denn es zeigt sich, dass dierechtlich verankerten Formen der Öffentlichkeitsbeteiligung nicht hinreichend sind, um sachorientiertewie emotionale Aspekte mit Betroffenen zu erörtern und Probleme lösen zu können.Zunehmend werden erweiterte Mitsprachemöglichkeiten bei Planungen und politischen Entscheidungsprozesseneingefordert, die zudem über die lokale Ebene und Planungsdetails konkreterEinzelprojekte hinausreichen. Der Blick in die Praxis zeigt, dass vielerorts in der Tat ergänzende Forender Meinungsbildung und Mitwirkung eröffnet werden. Wie dies konkret geschieht, ist jedoch eineoffene Frage. Denn insgesamt besteht nur wenig systematisches Wissen über die Praktiken undMethoden, mit denen Bürgerinnen und Bürger in die Erörterung von Zielen und Gestaltungsprinzipiender Energiewende, von Handlungsoptionen und konkreten Standortfragen eingebundenwerden. Will man derartige informelle Beteiligungsformen stärken, ist deshalb die Erarbeitung einesdifferenzierten Überblicks zu den angewandten Vorgehensweisen ein wichtiger Schritt. Dervorliegende Beitrag setzt hier an und legt in Form einer Beteiligungsmatrix eine Grundlage vor, nachder eine Systematisierung von Beteiligungsverfahren erfolgen kann.

Description: Deutschland wird weltweit als führend in der Förderung von erneuerbaren Energien und Energieeffizienz wahrgenommen. Die Energiewende ist international ein Vorbild. Mit seinen gewaltigen Potenzialen im Energiesektor ist Nordafrika ein lohnendes Ziel für die Entwicklungszusammenarbeit.

Description: Der globale Wasserbedarf im Energiesektor ist enorm. Ohne Politikwechsel wird er weiter stark wachsen. Dabei gefährdet Wassermangel schon jetzt die weltweite Energieversorgung. Vielerorts musste die Stromerzeugung aufgrund von Dürren oder Hitzewellen bereits vorübergehend zurückgefahren werden.

Description: The deep sea is the largest and least understood ecosystem on Earth. Nevertheless, the ocean floor could soon become the site of deep seabed mining operations. Efforts to develop an appropriate regulatory framework are well under way. Greater transparency will be critical to safeguarding ocean sustainability.

Description: Oceans, coasts, and marine resources are critical to the well-being of millions of people. Safeguarding ocean sustainability depends on the development of effective governance frameworks supported by strong capacities and institutions.

Description: Germany is widely acknowledged as a leader in the promotion of renewable energies and energy efficiency. The German energy transition is a source of inspiration worldwide. With its vast potential, North Africa is an important partner for development cooperation in the energy sector.

Description: The global water needs of the energy sector are large. Without policy changes, they will continue to grow. But already today, water constraints pose a threat to a secure electricity supply. In many parts of the world, droughts and heat waves have led to forced reductions in power generation.

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: We have developed a transportable spectroscopic nitrogen isotopic analyzer. The spectrometer is based on dual-modulation Faraday rotation spectroscopy of nitric oxide isotopologues with near shot-noise limited performance and baseline-free operation. Noise analysis indicates minor isotope (15NO) detection sensitivity of 0.36 ppbv·Hz−1/2, corresponding to noise-equivalent Faraday rotation angle (NEA) of 1.31 × 10−8 rad·Hz−1/2 and noise-equivalent absorbance (αL)min of 6.27 × 10−8 Hz−1/2. White-noise limited performance at 2.8× the shot-noise limit is observed up to ~1000 s, allowing reliable calibration and sample measurement within the drift-free interval of the spectrometer. Integration with wet-chemistry based on acidic vanadium(III) enables conversion of aqueous nitrate/nitrite samples to gaseous NO for total nitrogen isotope analysis. Isotopic ratiometry is accomplished via time-multiplexed measurements of two NO isotope transitions. For 5 μmol potassium nitrate samples, the instrument consistently yields ratiometric precision below 0.3‰, thus demonstrating potential as an in situ diagnostic tool for environmental nitrogen cycle studies.

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: 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: An unusual polyketide with a new carbon skeleton, lindgomycin (1), and the recently described ascosetin (2) were extracted from mycelia and culture broth of different Lindgomycetaceae strains, which were isolated from a sponge of the Kiel Fjord in the Baltic Sea (Germany) and from the Antarctic. Their structures were established by spectroscopic means. In the new polyketide, two distinct domains, a bicyclic hydrocarbon and a tetramic acid, are connected by a bridging carbonyl. The tetramic acid substructure of compound 1 was proved to possess a unique 5-benzylpyrrolidine-2,4-dione unit. The combination of 5-benzylpyrrolidine-2,4-dione of compound 1 in its tetramic acid half and 3-methylbut-3-enoic acid pendant in its decalin half allow the assignment of a new carbon skeleton. The new compound 1 and ascosetin showed antibiotic activities with IC50 value of 5.1 (±0.2) µM and 3.2 (±0.4) μM, respectively, against methicillin-resistant Staphylococcus aureus.

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: The Water and Global Change (WATCH) forcing datasets have been created to support the use of hydrological and land surface models for the assessment of the water cycle within climate change studies. They are based on 40-yr ECMWF Re-Analysis (ERA-40) or ECMWF interim reanalysis (ERA-Interim) with temperatures (among other variables) adjusted such that their monthly means match the monthly temperature dataset from the Climatic Research Unit. To this end, daily minimum, maximum, and mean temperatures within one calendar month have been subjected to a correction involving monthly means of the respective month. As these corrections can be largely different for adjacent months, this procedure potentially leads to implausible differences in daily temperatures across the boundaries of calendar months. We analyze day-to-day temperature fluctuations within and across months and find that across-months differences are significantly larger, mostly in the tropics and frigid zones. Average across-months differences in daily mean temperature are typically between 10% and 40% larger than their corresponding within-months average temperature differences. However, regions with differences up to 200% can be found in tropical Africa. Particularly in regions where snowmelt is a relevant player for hydrology, a few degrees Celsius difference can be decisive for triggering this process. Daily maximum and minimum temperatures are affected in the same regions, but in a less severe way.

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: 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: 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: 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: Several acoustic and optical techniques have been used for characterizing natural and anthropogenic gas leaks (carbon dioxide, methane) from the ocean floor. Here, single-camera based methods for bubble stream observation have become an important tool, as they help estimating flux and bubble sizes under certain assumptions. However, they record only a projection of a bubble into the camera and therefore cannot capture the full 3D shape, which is particularly important for larger, non-spherical bubbles. The unknown distance of the bubble to the camera (making it appear larger or smaller than expected) as well as refraction at the camera interface introduce extra uncertainties. In this article, we introduce our wide baseline stereo-camera deep-sea sensor bubble box that overcomes these limitations, as it observes bubbles from two orthogonal directions using calibrated cameras. Besides the setup and the hardware of the system, we discuss appropriate calibration and the different automated processing steps deblurring, detection, tracking, and 3D fitting that are crucial to arrive at a 3D ellipsoidal shape and rise speed of each bubble. The obtained values for single bubbles can be aggregated into statistical bubble size distributions or fluxes for extrapolation based on diffusion and dissolution models and large scale acoustic surveys. We demonstrate and evaluate the wide baseline stereo measurement model using a controlled test setup with ground truth information.

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: Antifungal bioactivity-guided fractionation of the organic extract of the sponge Polymastia boletiformis, collected from the west coast of Ireland, led to the isolation of two new sulfated steroid-amino acid conjugates (1 and 2). Extensive 1D and 2D NMR analyses in combination with quantum mechanical calculations of the electronic circular dichroism (ECD) spectra, optical rotation, and 13C chemical shifts were used to establish the chemical structures of 1 and 2. Both compounds exhibited moderate antifungal activity against Cladosporium cucumerinum, while compound 2 was also active against Candida albicans. Marine natural products containing steroidal and amino acid constituents are extremely rare in nature.

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: 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.

Description: Extreme, abrupt Northern Hemisphere climate oscillations during the last glacial cycle (140,000 years ago to present) were modulated by changes in ocean circulation and atmospheric forcing. However, the variability of the Atlantic meridional overturning circulation (AMOC), which has a role in controlling heat transport from low to high latitudes and in ocean CO2 storage, is still poorly constrained beyond the Last Glacial Maximum. Here we show that a deep and vigorous overturning circulation mode has persisted for most of the last glacial cycle, dominating ocean circulation in the Atlantic, whereas a shallower glacial mode with southern-sourced waters filling the deep western North Atlantic prevailed during glacial maxima. Our results are based on a reconstruction of both the strength and the direction of the AMOC during the last glacial cycle from a highly resolved marine sedimentary record in the deep western North Atlantic. Parallel measurements of two independent chemical water tracers (the isotope ratios of 231Pa/230Th and 143Nd/144Nd), which are not directly affected by changes in the global cycle, reveal consistent responses of the AMOC during the last two glacial terminations. Any significant deviations from this configuration, resulting in slowdowns of the AMOC, were restricted to centennial-scale excursions during catastrophic iceberg discharges of the Heinrich stadials. Severe and multicentennial weakening of North Atlantic Deep Water formation occurred only during Heinrich stadials close to glacial maxima with increased ice coverage, probably as a result of increased fresh-water input. In contrast, the AMOC was relatively insensitive to submillennial meltwater pulses during warmer climate states, and an active AMOC prevailed during Dansgaard–Oeschger interstadials (Greenland warm periods).

Description: The North Water (NOW) Polynya is a regularly-forming area of open-water and thin-ice, located between northwestern Greenland and Ellesmere Island (Canada) at the northern tip of Baffin Bay. Due to its large spatial extent, it is of high importance for a variety of physical and biological processes, especially in wintertime. Here, we present a long-term remote sensing study for the winter seasons 1978/1979 to 2014/2015. Polynya characteristics are inferred from (1) sea ice concentrations and brightness temperatures from passive microwave satellite sensors (Advanced Microwave Scanning Radiometer (AMSR-E and AMSR2), Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave Imager/Sounder (SSM/I-SSMIS)) and (2) thin-ice thickness distributions, which are calculated using MODIS ice-surface temperatures and European Center for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis data in a 1D thermodynamic energy-balance model. Daily ice production rates are retrieved for each winter season from 2002/2003 to 2014/2015, assuming that all heat loss at the ice surface is balanced by ice growth. Two different cloud-cover correction schemes are applied on daily polynya area and ice production values to account for cloud gaps in the MODIS composites. Our results indicate that the NOW polynya experienced significant seasonal changes over the last three decades considering the overall frequency of polynya occurrences, as well as their spatial extent. In the 1980s, there were prolonged periods of a more or less closed ice cover in northern Baffin Bay in winter. This changed towards an average opening on more than 85% of the days between November and March during the last decade. Noticeably, the sea ice cover in the NOW polynya region shows signs of a later-appearing fall freeze-up, starting in the late 1990s. Different methods to obtain daily polynya area using passive microwave AMSR-E/AMSR2 data and SSM/I-SSMIS data were applied. A comparison with MODIS data (thin-ice thickness ≤ 20 cm) shows that the wintertime polynya area estimates derived by MODIS are about 30 to 40% higher than those derived using the polynya signature simulation method (PSSM) with AMSR-E data. In turn, the difference in polynya area between PSSM and a sea ice concentration (SIC) threshold of 70% is fairly low (approximately 10%) when applied to AMSR-E data. For the coarse-resolution SSM/I-SSMIS data, this difference is much larger, particularly in November and December. Instead of a sea ice concentration threshold, the PSSM method should be used for SSM/I-SSMIS data. Depending on the type of cloud-cover correction, the calculated ice production based on MODIS data reaches an average value of 264.4 ± 65.1 km 3 to 275.7 ± 67.4 km 3 (2002/2003 to 2014/2015) and shows a high interannual variability. Our achieved long-term results underline the major importance of the NOW polynya considering its influence on Arctic ice production and associated atmosphere/ocean processes.