R08: Evolving Ocean

Evolution of calcification in extant coccolithophores
Dr. Magdalena A. Gutowska,  read more We have recently identified a unique morphological characteristic in the Isochrysidale coccolithophore Emiliania huxleyi [13]: E. huxleyi cells appear to be surrounded by a cell wall analogous structure. Such a morphology is unique among haptophyte species described to date and will have implications for differing mechanisms of substrate transport supporting coccolithogenesis. Our results support the earlier findings of Van der Wal et al. (1985) that proposed a multi-layer cell cover in E. huxleyi. Were this morphology limited to certain orders of haptophytes, it could be used as a defining trait to help resolve haptophyte phylogeny. Specifically, it could be used to clarify the divergence of the Isochrysidales and Syracosphaerales+Zygodiscales after their divergence from the Prymnesiales. Definitive characterisation of the cell wall analogous structure in E. huxleyi is necessary to understand its significance for the cellular biology of the species. In addition, detailed comparative morphological analysis of other coccolithophores is necessary to place these findings in an evolutionary context.

The role of metabolic rate depression phases in determining the maximum life span of Arctica islandica - molecular and biogeochemical investigations
Dr. Eva Philipp,  read more Elucidating the mechanisms underlying longevity is a pivotal challenge in biomedical sciences. The bivalve Arctica islandica is a unique model for ageing research as it is one of the longest-lived complex animal species on earth with a maximum life span of > 400 years. A repeatedly presumed strategy leading to the extreme longevity in A. islandica is the occurrence of self-induced phases of metabolic rate depression (MRD). Duration and frequency of MRD phases may vary between populations due to different environmental conditions like temperature or oxygen and thus might be one factor determining the difference in maximum life span observed between A. islandica populations. While a maximum age of 410 years is found for the Iceland population, A. islandica from the Baltic Sea population show a shorter life span of < 50 years. To investigate the role of MRD phases to attain a long life span and for a comprehensive overview of transcriptional changes under different oxygen/metabolic conditions, transcriptomes of normoxic, anoxic and reoxygenation treated individuals of A. islandica from the long lived Iceland population will be generated by pyrosequencing (Illumina). Gene expression changes will be analyzed with the help of a previously generated A. islandica transcriptome (2.9 mio reads, 454 technology). Gene expression analysis (qPCR) of selected candidate genes from the transcriptome approach will then be used to investigate population specific MRD responses under different oxygen (normoxia, anoxia, reoxygenation) and temperature (4, 7, 14 °C) regimes. Old individuals of both populations will be used for this approach and individual ages will be determined by age rings counts in the shell. Transcriptional responses will be compared with environmental temperature and oxygen conditions of the two populations, deduced from measurements of respective shell proxies (IFM-Geomar) and data-mining of literature and public databases. The results will provide insight whether MRD phases may be beneficial to attain a long life span and elucidate the role of environmental factors on modulating MRD patterns and maximum life span in A. islandica.

Transcriptome comparison of different Emiliania huxleyi morphotypes: identification of calcification related genes and determination if they are under selective pressure in a changing ocean
read more Together with photosynthesis and respiration, calcification is one of the key processes that impacts dissolved CO2 in the ocean. Coccolithophores are known to handle the main amount of calcification in the pelagic. A recent study has shown that type-R E. huxleyi morphotypes maintain highly calcified states despite low seawater pH, the reverse of general experimental findings. These recent results introduce an excellent experimental system to identify genes correlated to calcification. These genes will be analyzed for their phylogenetic relationship and then tested for selective pressure under future ocean conditions in different strains of E. huxleyi. General Aims - Identify genes responsible for different coccolith morphotypes and their reaction to changes in seawater carbonate chemistry. - Answer the question if we can expect changes in coccolith calcification and/or a shift in morphotype under future ocean conditions and therefore detect selective pressure. - Describe a puzzle piece in the process of coccolithophore calcification and decipher the sensitivity of a key process considering rising CO2-levels.

The drivers of algal invasion success: adaptation and co-evolution of resistance towards foulers?
Dr. Mahasweta Saha,  read more Biological invasions have become one of the most prominent elements of global change and are occurring with increasing frequency both in terrestrial and aquatic ecosystems. Spread of macroalgae beyond their native habitat has become an increasing ecological and economical problem. The interactions between introduced species and their enemies have been often proposed as key processes that determine invasion success. and three main hypotheses have been postulated. A species introduced to an exotic area may leave behind many of its enemies (e.g. herbivores, foulers, pathogens), but it may also encounter a new set of potential enemies in the invaded area. When the new potential enemies fail to recognize the introduced species as a suitable host the invader may experience a decrease in regulation by herbivores and other natural enemies (e.g. foulers, pathogens) compared both to the native range and to competitors from the new range, which may then result in a rapid increase in distribution and abundance (Enemy Release Hypothesis (ERH)). On the other hand, when the new enemies are able to attack the newly arrived un-adapted non-native species, they have the potential to prevent the successful establishment and spread of the introduced species (Biotic Resistance Hypothesis). But even when the enemies in the new area recognize the introduced species as potential prey, the latter may possess defensive mechanisms which the enemies do (not yet) tolerate (Novel Weapon Hypothesis, NWH). Thus, well defended individuals or populations are more likely to be able to establish themselves and spread in a new environment even when intense pressure from its major enemies i.e. herbivores, pathogens and foulers exists. To date, quite a few studies have been able to demonstrate that certain invasive algal species have invested in increased defense (towards herbivores) when compared to their native range. Even though both herbivores and foulers can exert selective pressures and regulate the establishment and spread of exotic seaweeds, no attempt has been made yet to understand whether exotic seaweeds might also regulate their antifouling chemical defense to cope with the native foulers existing in the new habitat. Goal of this proposal is to determine how the antifouling defense capacity of invasive algal species (using the East Asian invasive red alga (Gracilaria vermiculophylla)) has evolved during the invasion process?

Emerging marine diesease: why to shift from friendly to nasty
Prof. Hinrich Schulenburg,  read more Pathogens exert extreme selective pressure on their hosts and are highly prevalent in the marine realm and thus of central importance for marine ecosystem dynamics. Yet, to date, we still lack precise understanding on the complexity of environmental changes that determine shifts in pathogen virulence and thus influence the dynamics of host-pathogen interactions in the oceans. We here aim at developing a “virulence-atlas” for the most abundant marine pathogens from the genus Vibrio. We will take a multidisciplinary approach by integrating several virulence parameters in over 200 isolated Vibrio strains, infection experiments in two established host systems, and candidate virulence gene analysis, in each case under alternative environmental conditions. This project will yield a comprehensive baseline data set essential for an in-depth understanding of the consequences of emerging marine diseases under future scenarios of global change.

Measuring and modeling the effect of calcification on seawater carbonate chemistry in Kiel mussel reefs
Dr. Claas Hiebenthal,  read more Ocean acidification caused by human emissions of CO2 rose as a major thread threat to calcifiers like the mussel Mytilus edulis. This species is a key reef builder of the European nearshores and is of paramount commercial importance. However, the fluctuations of the carbonate system in those reefs, induced by the mussel physiology, remain unknown. Filling this gap of knowledge is essential for evaluating the impact of ocean acidification on these crucial ecosystems. To do so, in a synergistic effort between marine chemists, ecologists and physiologists from academic and private sector, we will 1) combine state-of-the-art technologies to create an in-situ high accuracy and precision carbonate sensor 2) deploy it in mussel beds of the western Baltic Sea at key periods of the Baltic CO2 annual cycle 3) explain the variations with a statistical model.

Insight to the Evolution of Metaorganisms from an ancient Ocean Invader
Prof. Philip Rosenstiel,  read more Understanding the evolution of metaorganisms, composed of a multicellular host and its associated microbiota, is a fundamental topic in biology and medicine. Basal marine invertebrates allow an insight into the early co-evolution between bacteria and innate immune response machinery. Genetically distinct invasion waves of the ctenophore Mnemiopsis leidyi offer the opportunity to test immune learning and pre-adaptation to associated microbiota in this unexplored phylum. In a common garden experiment ctenophores of different genotypes will be repeatedly exposed to previously known or unknown (novel) bacteria. Expression of immune genes together with microbiota composition after this treatment will be assessed through next generation sequencing. The results will allow new insight into the plasticity of the very basal immune pathways in co-evolution with associated microbiota.

Automated high-­resoluton imaging system for non-invasive in situ measurements of marine partcles and zooplankton
Dr. Rainer Kiko,  read more Automated underwater imaging systems offer the unique opportunity for non-invasive determination of plankton composition and particle size distribution in the natural environment. In situ imaging systems have a number of advantages over traditional net-based approaches, including high spatial resolution (e.g. to obtain vertical gradients), detection of unperturbed particle size spectra, and automated data analysis. Because existing systems were engineered for deep-water deployment and ship-based operations, their size and weight precludes their use in mesocosm studies and their operation from small boats. Moreover, the rapid development in CCD chip technology makes it possible now to design imaging systems with much higher resolution than presently available. We propose to work jointly with the group of Prof. R. Koch (Multimedia Information Processing) and a local industrial partner (Develogic GmbH, Hamburg) to develop an automated lightweight underwater high-resolution imaging system (KielVision) for in situ determination of zooplankton composition and particle size spectra. During the next three years, the newly developed system will be used during KOSMOS experiments off Sweden, Gran Canary, and Peru, time-series measurements at Boknis Eck and in the Kiel Fjord, and an SFB754 cruise to the tropical Eastern North Atlantic.

Invasion of Mediterranean mussels into a warming Baltic Sea: will hybridization with local mussels impact emerging aquaculture enterprises?
read more Recent evidence for the occurence of invasive Mediterranean blue mussels (Mytilus galloprovincialis) in the Baltic Sea1 indicates that in the future, local mussel communities might become a mixture of hybrids between M. galloprovincialis and the native M. edulis x M. trossulus hybrids, particularly when considering future climate change scenarios. As hybridization can affect many ecologically and economically relevant traits, it is paramount to obtain a deeper understanding of the current genetic composition of Baltic Sea mussel populations. We propose to test for reproductive barriers between the three species and to study, whether emerging aquaculture enterprises might be endangered by extensive hybridization of mussels. Hybridization can lead to mussels with reduced shell strength and growth performance, a significant economical problem for mussel aquacultures. We propose to analyze population genetics of local hybrids using next generation transcriptome sequencing and crossing experiments. Further, we propose to measure fitness of generated hybrid offspring under different abiotic conditions, model larval drift to estimate population connectivity in the Baltic Sea and test for performance of hybrids in a local aquaculture enterprise.

Evolutionary feedback in a tripartite species interaction
Dr. Carolin Wendling,  read more In the marine environment animals are constantly subjected to a cocktail of microbes of which some pose a major threat as they can establish severe infections. The propensity of a bacterium to shift its virulence is often initiated by a third biological player i.e. bacteriophages that integrate into the genome of mutualistic bacteria and turn them into severe diseases (i.e. lysogenic conversion). However, interactions between more than two players are complex and have largely been neglected in empirical host-parasite research, and thus little is known about the evolutionary consequences of such altered interactions. I suggest studying a tripartite interaction using a well-established model system consisting of pipefish, Vibrio and their temperate phages. Looking at dual interactions, host local adaptation was discovered between pipefish and Vibrio bacteria. In a cross-infection matrix of Vibrio and temperate phages two distinct groups of phages, i.e. generalists (broad host range) and specialists (narrow host range) were found. I now propose to integrate these findings and combine both dual systems into a tripartite interaction. To achieve this aim, I will use experimental evolution to let generalist phages evolve into specialists and vice versa. Next, I want to identify genomic changes during host range evolution by means of whole genome sequencing on both bacteria and phages. I will then determine the evolutionary feedback of such altered species interactions to test two hypotheses: (1) generalist phages will increase Vibrio virulence due to lysogenic conversion which will ultimately result in an increased disease risk for pipefish and (2) such altered species interactions at the phage-bacteria level will disrupt local host adaptation at the bacteria-pipefish level.

From genes to holobiont: identifying unifying physiological processes that determine sensitivities in times of climate change
Dr. Marian Hu,  read more Large scale predictions regarding species sensitivities in a changing ocean require identification and understanding of common physiological principles that determine the degree of sensitivity in marine organisms. Larval stages are often the weakest link when a species is exposed to challenging environmental conditions making these life stages particularly interesting for this research. However, very little is known regarding physiological aspects of marine larval stages, primarily due to the fact that these organisms are very small. Recently developed techniques allowed us to study physiological processes in larval stages, and demonstrated that digestive processes in larval stages of early deuterostomes (echinoderms and hemichordates) seem to represent a critical factor for sensitivity towards ocean acidification. Interestingly, the digestive milieu of these organisms is highly alkaline (~pH 10) and acidified conditions decrease digestion abilities, and thus, food assimilation [1]. Thus, the first part (WP1) of the present project aims at deepening our current understanding regarding the mechanisms and energetics of gastric alkalization in selected echinoderms. In a second step (WP2) this knowledge will be transferred to other protostome groups such as lophotrochozoans (e.g. mollusks) in order to create a wider comparative basis to identify unifying physiological processes responsible for sensitivity towards environmental pH/pCO2 fluctuations. There is increasing evidence that the gastrointestinal microbiome is an essential part and specifically influences the performance of organisms. Digestion ability and pH may be determinants of this microbiome. Therefore, this project will identify and characterize bacteria associated with alkaline larval digestive systems (WP3) in order to broaden our knowledge regarding potential host-symbiont interactions under acidified conditions. WP1-3 are well embedded in the cluster of excellence The future ocean, and will integrate scientists from different research areas (e.g. R3 and R4) as well as national and international collaborators.

Deciphering the Lost Years, novel in‐situ/silico tracking of neonate seaturtles
Dr. Arne Biastoch,  read more The dispersal of juvenile organisms drives the life-history evolution, dynamics and habitats of many endangered marine vertebrate populations. However, the movements/behaviours of small organisms, like hatchling sea turtles, remain enigmatic. We thus propose a novel interdisciplinary campaign to utilise advances in the miniaturisation of animal tracking devices and conduct the first multi-day hatchling tracking study to gain crucial information on their movements/swimming behaviours whilst dispersing offshore. Custom-made “hatchling shaped drifters” will also be released into the ocean to acquire in-situ Lagrangian data on surface currents experienced by hatchlings and to track passive dispersal trajectories. These observations will be analysed in-silico with currents and particle drift simulated using ocean models that resolve current variability down to length scales of c.10 km.

The extra‐cellular genetic capacity of marine microbial communities
Dr. Anne Kupczok,  read more Lateral gene transfer (LGT) is an important mechanism of natural variation in prokaryotes. Here we propose to develop a novel methodology, termed fractionated metagenomics, for the characterization of mobile DNA elements within a given microbial community. Our method will enable the comparison of genetic connectivity features across different environments and within-host microbiota in a cultivation-independent manner. This includes the transferable genetic content, gene transfer mechanisms and the distribution of genetic content among DNA vessels. Applications of our approach to the same microbial community in a time-dependent manner, under similar or varying environmental conditions, will be useful for quantifying spatiotemporal dynamics of genetic connectivity. Our method will be highly useful for researching stress response and adaptation processes of free-living and host-related microbial communities in the changing ocean.

Parametric rotated sonar as a new tool for versatile seafloor classification
read more Acoustic surveying using singlebeam echosounders represents one state of the art technology for seafloor classifications by echo shape analyses. In turn swath sonar multibeam offers an alternative by inversion of acoustic angular response into seafloor properties. We suggest combining both approaches for the first time with a novel technique providing swath capabilities to singlebeam systems. The new approach additionally targets near-subbottom volume scattering as a potentially reliable habitat proxy that has been neglected so far. The approach has the potential for a much improved seabed classification compared to previous approaches by introducing angular response and nearsubbottom scattering analyses together with statistical tools.

Single cell genomic insights into phytoplankton‐virus interactions
Prof. Ute Hentschel Humeida,  read more Primary production losses by viruses are about as high as those via grazing (consumption), yet phytoplankton-virus interactions are only poorly understood. Single-cell genomics is one promising new tool to address directly diversity and specificity of such interactions. We will sample Emiliania huxleyi genotypes during phytoplankton blooms that are killed upon attack by Phycodnaviruses. In doing so, we will address viral diversity in E. hux cells in an unbiased approach. Such data are urgently needed to model the ecology of the infection as well as to analyze co-evolutionary patterns, which will ultimately lead to a better understanding of the genomics of viral lysis of phytoplankton blooms.

All‐in‐focus: Combining lightfields and shadowgraphs for advanced underwater imaging
Dr. Kevin Köser,  read more Underwater imaging has emerged as a valuable tool in biological oceanography, allowing for non-invasive in situ quantification and classification of organisms and particles at high spatial and temporal resolution. Qualitative and quantitative information encompassing multiple trophic levels is crucial to improve our mechanistic understanding of food-web dynamics and the vertical flux of organic matter to the deep ocean. However, despite significant progress over the last decades, no instrument exists that can obtain high-resolution images of marine organisms over a wide size spectrum (few μm to several cm). We will solve this interdisciplinary problem by constructing the All-In-Focus imaging system (AIF), a single unconventional and novel imaging system that will unify a lightfield camera system and a shadowgraph approach in one single system. The lightfield camera system allows the retrieval of three-dimensional information and greatly enhances the depth of field in comparison to standard cameras whereas the shadowgraph imaging approach allows to image a wide size spectrum of objects in a large image volume. This project is attended with high risk, since lightfield technology is still a novel area subject to research and has never been used before in underwater settings and is therefore unlikely to be funded by 3rd party organization. As a result of our institutional partnership, we will combine our domain specific knowledge, computational camera systems and lightfield imaging at the CAU and the experience in underwater imaging at the GEOMAR, in this solution-oriented project to significantly improve our abilities to image the ocean.

Matching and the origin of marine species
Prof. Oscar Puebla,  read more The award of the 2012 Nobel Prize in Economic Sciences to the two main founders of matching theory, Alvin E. Roth and Lloyd S. Shapley, corroborates the fundamental importance and specificity of this theoretical framework. Yet matching theory has been largely ignored in the biological sciences, notwithstanding the potential provided by this approach to address mate choice and sexual selection. Here, we propose to use matching theory to explore the role played by sexual selection in the origin of species. We will consider the hamlets (Hypoplectrus spp), brightly coloured reef fishes from the tropical western Atlantic, as a marine model system. Preliminary data suggest that this approach has the potential to challenge current paradigms about speciation and, in the longer term, open up an entirely new research area. In the midst of a global extinction crisis, an understanding of speciation - the only counterbalancing force to extinction - is not only a fundamental question, but also a pressing issue.

Life in a toxic environment: How do extreme redox conditions affect oceanic N2 fixation?
Dr. Hermann Bange,  read more Nitrogen (N) is a limiting element of life in the ocean. Nitrogen fixation, the biological reduction of dinitrogen gas (N2) to ammonium, is quantitatively the most important external source of new nitrogen to the ocean and mostly depends on the availability of a phosphorous (P) and iron (Fe) source. While oxygen (O2) depletion favors N2 fixation, the presence of hydrogen sulfide (H2S) under conditions of extreme anoxia may hinder that process by (i) a direct toxic effect on the diazotrophic community and (ii) immobilization of Fe through precipitation of Fe sulfide minerals. In order to explore the sensitivity of N2 fixation to changes in O2 and H2S, we propose an interdisciplinary field study at the time series station Boknis Eck, located in the Eckernförde Bay (www.bokniseck.de), serving as a natural laboratory. This allows an incomparably detailed monitoring of the diazotrophic response to naturally occurring extreme changes in redox conditions. We further aim to explore the potential of the responsible microbial community to adapt to rapidly changing redox conditions in a chemostat. The results are crucial to understand basic controls of N2 fixation and primary productivity over various geological timescales and to further predict them in a changing ocean.

The role of hybridization and microbial associations for invasion success in a comb jelly
Dr. Cornelia Jaspers,  read more Marine invasive species have globally increasing biological and economic impacts. However, the role of hybridization and subsequent changes in microbiota structure, favoring range expansion and invasiveness remain poorly understood. In controlled experiments, recently formed hybrid populations along with ancestral control lines will be exposed to stress. We will investigate fitness effects of hybridization as well as microbiota changes using tagged amplicon sequencing in one of the most notorious marine invasive species, the comb jelly Mnemiopsis leidyi. Results will reveal whether or not hybridization leads to outbreeding depression or increased hybrid vigor and to what degree the microbiota differs among native, invasive and hybrid populations. This will help to understand fitness consequences due to hybridization and its possible contribution to acceleration of invasion success.

Experimental evolution going wild
Prof. Rüdiger Schulz,  read more A major unknown in predicting the consequences of ocean change for marine life is the ability of organisms to adapt to changing environmental conditions. The question hereby is not whether adaptation can occur but whether it can occur rapidly enough to maintain ecosystem function and services unchanged1. The adaptive potential is proportional to the population size and generation time, with highest adaptation rates expected for species with large population sizes and short generation times2. While these two criteria are met by many taxa in the pelagic and benthic realms, a surprisingly small number of studies have investigated the evolutionary adaptation of marine organisms to ocean change3-8. Existing approaches in experimental evolution generally involve laboratory culture experiments on isolated species, leading to a trade-off between uncovering general evolutionary mechanisms and understanding how they apply in complex natural environments. To overcome this limitation, we propose to take experimental evolution into the wild by conducting a long-term in situ CO2 perturbation experiment with natural plankton communities under close to natural conditions. From this experiment, which will be the first of its kind, we expect to provide a unique data set on the potential for evolutionary adaptation to ocean acidification in key plankton groups within their natural environment.

From one‐ to three‐ dimensional thinking in global change research: Adding fluctuations to the usual static treatments may drastically change our understanding of pending environmental shifts.
Dr. Andreas Lehmann,  read more Climate change is projected to not only shift environmental means but to also increase variability around means and the intensity of extreme events. This may exert additional stress to organisms, or, in contrast, provide transient refuges from stress. We hypothesize that (i) fluctuating temperature stress will very differently affect marine organisms as compared to constant stress of the same mean intensity, and that (ii) the two additional dimensions of a stress regime, stress intensity (amplitude) and stress duration (frequency), will determine the biological impact. We will also analyse temperature time series of coastal Baltic Sea habitats with respect to shifts in any of these dimensions. By analysing on-going shifts in fluctuations in the context of sensitivities of organisms, observed from the lab experiments, we will be able to make more realistic predictions of climate change impacts on ecosystems.

How important is epigenetic variation for adaptation to global change?
Prof. Hinrich Schulenburg,  read more In the course of climate change, salinity levels inside the Baltic Sea are predicted to decrease drastically, and Baltic Sea species will face environmental shifts. To maintain viability confronted with changing conditions, adaptive potential is essential. Besides genetic diversity, epigenetic mechanisms are thought to contribute to phenotypes, due to their function in transcriptional regulation, and thus provide a possible machinery to influence the adaptive potential. We plan to screen epigenetic marks, i.e. DNA methylation, in three-spined stickleback populations from locations with different salinity regimes and to compare this to the genome-wide distribution of genetic variability. With the inference of the contribution of epigenetic variation to adaptation processes and its interrelationship with the underlying genetic diversity, we want to understand how species cope with the predicted climate change.

Seeing is believing ‐ localisation of quorum sensing secondary metabolites on seaweed holobiont by imaging techniques
Prof. Ruth Schmitz-Streit,  read more This project aims to map spatial localization and identification of quorum sensing (QS) secondary metabolites on the Baltic seaweed Fucus vesiculosus. A combination of three powerful visualization techniques, scanning electron microscopy (SEM), catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) and desorption electrospray ionization mass spectrometry (DESI-MS) imaging will be used to analyze the complex assemblage of surface microbiome and to describe hot spots producing QS metabolites. Secondary metabolites (SMs) of the i. microbial epibiota, ii. epibiont-free algal surface and iii. interior algal tissues will be differentially located and identified by highly sensitive metabolite profiling. The identified phylogenetic information and genetic pathway identification of the surface microbiome will be related to with QS activity and spatial distribution. We aim to pinpoint secondary metabolite locations of F. vesiculosus to shed light into chemical communications between hostmicrobe and potentially intermicrobial interactions on selected seaweed microregions.

Characterizing trophic links in pelagic ecosystems with stable isotope fingerprinting of amino acids
Dr. Nils Andersen,  read more We propose investigating major trophic pathways within the pelagic system of the Sargasso Sea by applying a novel set of amino acid
13C and
15N markers. These provide a powerful tool for inferring major source of primary production, trophic position of consumers, and potentially also the macromolecular composition of the diets. In contrast to bulk isotopes, the compound specific markers can be used without adjusting for variable isotopic baseline values. Developing sensitive in situ markers for pelagic ecosystems is important in light of anthropogenic disturbance and global change.

Autonomous oceanic turtle drifters
Dr. Rebecca Scott,  read more Dispersal is a key life history trait amongst marine species. However many organisms, like hatchling sea turtles, are too small to be tracked. Here, we plan to develop novel autonomous oceanic turtle drifters that can be tracked via satellite to collect vital data on surface ocean currents and the impacts of active directional swimming on the dispersion of small organisms reliant on ocean currents for their survival and long distance dispersal. These observations will be analysed in-silico with currents and particle drift simulated using ocean models and key biological data.

MicroZooImager: An integrated optical system for microzooplankton analysis
Dr. Jan Taucher,  read more Microzooplankton, a group of heterotrophic organisms in the size range of 20-200 μm, are major consumers of marine primary production in the world oceans. Data on their taxonomy and biomass is traditionally obtained by microscopy, which is very labor- and time-intensive. This impedes a high spatial and temporal resolution of data, which would be needed to improve our mechanistic understanding of the role of microzooplankton in marine ecosystems and carbon cycling. To solve this problem, we propose to develop a novel imaging system for rapid data acquisition on microzooplankton abundance, biomass, body size and taxonomy. The instrumental design will be based on a high-resolution line-scan camera with telecentric optics and illumination and provide high-quality images of the multitude of microzooplankton specimen contained in natural plankton samples. Acquired images will be analyzed with existing software for image processing and automated classification, thus allowing for a swift workflow and acquisition of final data. Our interdisciplinary project unifies marine ecology, optical engineering, and computer sciences with the ultimate goal of establishing a rapid and efficient method for studying microzooplankton communities.

Mercury and dimethylmercury pollution in the ecosystem of the Kieler Förde as a result of historical use of air defence ammunition
Prof. Edmund Maser,  read more This project will study the distribution and fate of elemental mercury (Hg) and methylated Hg in the southwest Baltic Sea, and the biomagnification of these toxic substances in the aquatic food chain. These Hg compounds are anthropogenic pollutants and pose a threat to ecosystem and public health, and are thus of concern to regulatory authorities of Schleswig-Holstein. We will investigate strongly polluted and control sites, with a specific focus on a region off Kiel where >1.2 million mercurycontaining anti-aircraft grenades were shot from World War II artillery training grounds and now litter the seabed. The main aim of this study is to determine the distribution of Hg in the waters and sediments of the southwest Baltic Sea derived from munitions deployed >70 years, and how much has moved into the food chain. The project will provide direct policy relevant information to the Schleswig-Holstein government on compliance of this EU Water Framework Directive Priority Compound.

Understanding physiological processes to improve animal welfare and production capacity of shrimp aquaculture systems in Schleswig-Holstein
Dr. Marian Hu,  read more Shrimp aquaculture leaves a tremendous footprint on the coastal zone of many tropical countries (e.g. via deforestation of mangrove ecosystems) and animals are often treated with heavy doses of antibiotics to fight bacterial diseases1. Recently, a recirculating shrimp aquaculture farm has established itself in Kiel that produces animals that are free from antibiotics. However, due to the high stocking densities necessary to operate economically, the system accumulates CO2, which impacts animal physiology and welfare, as well as system productivity. Here, we propose a transdisciplinary approach to investigate how high CO2 experienced in shrimp farms influences animal acid-base status and how this impacts animal behavior, growth performance, shrimp palatability and shrimp susceptibility to bacterial disease. In addition, we propose to characterize the carbonate system dynamics within the shrimp farm in order to develop measures to help stakeholders create carbonate system conditions that increase animal well–being, productivity and product sensory quality at the same time.

Otolith time machines: unlocking the potential of historic fish sample archives to reconstruct the past
Prof. Ulrich Sommer,  read more Rapid shifts of entire ecosystems, termed “regime shifts”, are severe but poorly understood consequences of global change. To understand such shifts, we propose to investigate the processes underlying the Baltic regime shift in the 1980s using archived otoliths. Specifically, we aim to retroactively characterize long-term (1978-2016) changes in benthic vs. pelagic feeding of the top predator cod by applying traditional bulk sulfur and nitrogen stable isotope and novel single compound carbon stable isotope analyses to otolith protein samples for the first time. If successful, the resulting case study will set a precedent for the use of historical sample collections to elucidate biological implications of global change.

Revealing Cape Verdean marine hotspots: Multidisciplinary, long-term and high-resolution observations with a novel Modular Ecosystem Observatory
Dr. Sascha Flögel,  read more Cape Verde (CV) waters are the habitat of unique populations of pelagic predatory fishes and sharks. A poor understanding of key regions for these predators and their prey prevents proper management and conservation and underlines the need for ecosystem data. We propose to develop an interlinked, multidisciplinary and modular ecosystem observatory that will enable the assessment of temporal dynamics of predators and prey in their biogeochemical and physical environment, using seamounts as testbeds for our proof of concept.

Can assisted evolution help restore heat-wave damaged coral reefs?
Prof. Frank Melzner,  read more Coral reefs provide goods, services and revenue for many tropical countries. Yet they are degrading at unprecedented rates due to climate change. Thus, urgent actions are necessary to protect and restore these fragile ecosystems. We propose a transdisciplinary project that aims at identifying coral populations that are genetically adapted to cope with higher heat stress. We then want to use these genotypes in a novel selective breeding approach to facilitate reef restoration through assisted evolution. The Andaman Sea (Thailand), harboring one of the most diverse coral reef assemblages, will serve as our natural laboratory. Here, large amplitude internal waves (LAIW) have rendered some coral populations more heat stress-resistant1,2,3. We will test, whether these populations are genetically distinct from more vulnerable populations and will scan genomes for targets of selection to high temperature stress. In parallel, we will evaluate the potentials and risks of assisted evolution approaches4 to reef restoration by organizing a stakeholder workshop with governmental and non-governmental organizations to establish a long-term road map to protect reef ecosystems along the Thai coast.

Ammonia tolerant, diapausing copepods as model system for hepatic encephalopathy
Prof. Markus Bleich,  read more Hepathic encephalopathy (HE) is a common and potentially life threatening disease that results from impaired liver function or liver failure. Liver failure causes high plasma ammonia levels, which have been associated with swelling of glial cells (astrocytes), brain edema, and, subsequently, severe neurological damage due to increased intracranial pressure and mortality. While detrimental plasma ammonium levels in mammals typically are <1 mM, recent findings indicate that diapausing copepods accumulate plasma ammonium in excess of 200 mM for months. Owing to similarities in basic central nervous system (CNS) architecture, we believe that understanding mechanisms of high ammonia tolerance in copepods can aid in a better understanding of HE pathophysiology and contribute towards improved disease treatment in humans. We propose to use a range of techniques to characterize ammonia detoxification pathways, brain ultrastructure and brain functional impairment in copepods exposed to high plasma ammonia concentrations. This research is important for understanding diapause biology in copepods, the most important zooplankton group, and will help us learn more about how cells cope with high ammonium concentrations.