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Current Projects

  • CDRmare: Research Mission of the German Marine Research Alliance (DAM) »Marine carbon sinks in decarbonisation pathways«

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    In order to support pathways to mitigate the increasingly drastic consequences of human-made climate change and to achieve the Paris Agreement goals, the removal of CO2 from the atmosphere will be an important measure alongside massive CO2 emission reductions.

    The research mission CDRmare (CDR: Carbondioxide Removal – CO2removal) will investigate whether and to what extent the ocean can play a significant role in the removal and storage of CO2 from the atmosphere. It will also consider the linkages with and impacts on the marine environment, Earth system, and society, as well as appropriate approaches for monitoring, attributing, and accounting for marine carbon storage in a changing environment.

    The research mission will establish relevant assessment criteria and, in the long term, a Marine Carbon Roadmap for the sustainable use of marine carbon storage at regional to global scales, in close dialogue with stakeholders.

  • ASMASYS: Unified ASsessment framework for proposed methods of MArine CDR and interim knowledge SYnthesiS 

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    Within ASMASYS, a transdisciplinary evaluation framework for marine CDR options will be developed as the base for a uniform evaluation of the different marine CDR options, and as a nucleus for further homogenization with the evaluation of CDR options on land. Strong emphasis will be put on non-natural science aspects, including criteria addressing legal, social, and ethical aspects, as well as political framing and policy-inherent internal mechanisms. Current gaps in the evaluation chain will be analysed. ASMASYS will also address the current hurdles with respect to the permission of demonstration projects involving field studies, which are an indispensable prerequisite for full scale technical application. In particular, sustainability will be a strong component of the assessment framework, using the UN Sustainable Development Goals (SDGs) as criteria. The current knowledge on some marine CDR-options not covered by the joint projects of the DAM mission will be compiled, including recent progress and development in other international initiatives. Knowledge of methods addressed within the research mission will be requested from the funded projects of the FM and compiled with regard to the assessment framework. The marine CDR options under consideration in the mission will be assessed in detail using the developed assessment framework. Based on this, an interim synthesis will be provided, and potential new directions for the 2nd funding phase of the Research Mission will be identified. During the entire course of ASMASYS, strong interaction and exchange is foreseen with all projects of the mission, currently active international research activities, stakeholders, and the synthesis project of the CDR-funding-line. The transfer component within ASMASYS will assure involvement of specialists and stakeholders during the development of the evaluation framework, and provide tailored dissemination products for the scientific community, decision makers, and the public. Special attention will be paid to ensure that the work results and products of ASMASYS are of relevance for the national climate strategy of Germany.
  • RETAKE: CO2 removal by alkalinity enhancement: potential, benefits and risks

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    The research consortia RETAKE will assess the potential, feasibility and side effects of various forms of marine alkalinity enhancement (AE) as a means to reliably and sustainably remove CO2from the atmosphere. Increased ocean alkalinity reduces the activity of CO2 in seawater, and prompts an enhanced flux of CO2 from the atmosphere into the ocean, thereby reducing the atmospheric CO2 concentrations. REATKE will examine a range of mineral alkalinity sources with respect to dissolution kinetics, CO2 sequestration potential and side effects on chemistry and biology. 

    Laboratory studies and mesocosm experiments of AE in benthic and pelagic systems will simulate realistic environments with focus on the Baltic and the North Sea. A hierarchy of numerical models will be used to simulate deployment in German coastal waters and elsewhere, and to extrapolate experimental results from local to regional and global scales. Permanence and accounting of carbon storage as well as monitoring, detection and attribution issues will be examined against the background natural variability. An investigation of economic aspects and the relation to the U.N. sustainability goals will complete the comprehensive assessment in order to inform policymakers about the feasibility, overall sequestration potential and environmental risks of ocean alkalinity enhancement.


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    CARBOSTORE (Carbon Storage in German Coastal Seas - Stability, Vulnerability and Perspectives for Manageability) is a joint project funded by the Federal Ministry of Education and Research (BMBF) in the research program "MARE: N - Coastal, Marine and Polar Research for Sustainability” under the umbrella of the Research Framework Program“ Research for Sustainable Development” (FONA).

    With reference to the BMBF tender of July 26, 2019, CARBOSTORE is particularly dedicated to the “analysis of interactions between physically conditioned and biogeochemical cycles (especially CO2 uptake / biological pump) under the combined influence of global change and other directly anthropogenic influencing factors”. This question is being investigated for the two marginal seas, the North Sea and the Baltic Sea, whose coastline runs partly through German territory.

    The main goal of CARBOSTORE is to investigate the stability and vulnerability of various carbon stores in the German tributaries of the North and Baltic Seas. For this purpose, it is checked whether and to what extent processes that are responsible for carbon storage are or will be influenced. Based on these studies of vulnerability, and taking into account the relevant legal and socio-economic framework conditions, perspectives are developed that allow the targeted increase in carbon storage in the North and Baltic Seas, ie, net negative CO2emissions, have the objective.
  • (For details click here)
    Methane is a known greenhouse gas that severely enhances climate change on earth, yet not all methane sources into atmosphere have been identified. A process that might be of importance is the production of methane by microorganisms within the anoxic guts of certain zooplankton species and their fecal pellets. This production takes place in the upper oxygenated water column and thus could have a direct impact on the methane flux between ocean and atmosphere. We hypothesize that highly productive regions like marginal seas, which have never been studied in detail in this context before, are areas of enhanced zooplankton-mediated methane production, which most probably causes the subthermocline methane anomaly that have been sporadically identified in the oxygenated water column of the Baltic Sea. In the ZooM project, we will combine methane chemistry, microbiology, and zooplanktology in a multidisciplinary approach to investigate zooplankton-associated methanogenesis in detail using the Baltic Sea as a model system. We plan to investigate the following key questions: (1) Is the subthermocline methane anomaly a widespread phenomenon in the Baltic Sea, which shows a temporal and spatial variability? (2) Does zooplankton-associated methane production have the potential to support the methane anomaly in the shallow water and how are copepod species and environmental factors like food composition influencing methane production? (3) Which microbes are involved in zooplankton-associated methane production and can we detect differences in methanogenic assemblages and their activities between copepod guts and their fecal pellets?
  • (For details click here)
    Within BONUS INTEGRAL, the partners from eight institutions and five nations aimed to: (1) Integrate the different data streams of ICOS and related infrastructure in the pan-Baltic area, (2) Provide better charts of seasonal carbon dioxide and GHG flux over the Baltic Sea, including advanced remote sensing approaches, (3) Integrate the carbon system into a high-resolution 3D-model, which will contribute to a better description of the biogeochemical coupling of eutrophication and deoxygenation, (4) Demonstrate the added value for a better biogeochemical ecosystem status description of the Baltic Sea, (5) Advise the implementation of ICOS in the south-eastern countries of the Baltic, and actively promote components strengthening the value for Baltic Sea ecosystem status assessment, (6) Develop, in close interaction with stakeholders, strategies for a better, cost-efficient monitoring approach for the Baltic Sea by integration of ICOS and related data. The rationale for the work carried out in BONUS INTEGRAL is the conviction that for the Baltic Sea, cause-reaction relations between measures to combat eutrophication and the ecosystem response cannot properly be evaluated and predicted without a sound understanding of the carbon cycle. Moreover, monitoring carbon system parameters is a prerequisite for any attempt to trace acidification in the Baltic Sea. Lastly, in the era of greenhouse gas accounting, a budget of greenhouse gas fluxes between the Baltic Sea and the atmosphere and its human- and climate induced changes should be known as an indicator of ecosystem health.

Concluded Projects

  • (For Details click here!)
    The process of microbial methane oxidation in the water column is only insufficiently investigated. Water column studies in the vicinity of gas bubble releasing seep sites show, that the majority of dissolved methane is immediately oxidized by microbes after its injection into the water body, and that only a small fraction of methane is reaching the surface water and the atmosphere. In this project, our multidisciplinary approach is investigating the link between sedimentary and pelagic methanotrophy at gas bubble releasing seep sites (study area: Coal Oil Point, Santa Barbara Basin, California). We hypothesize that at these sites methane oxidizing microbes are transport by gas bubbles from the sediment into the water column. In detail we use gas chemistry and molecular biology to (1) identify the zone of methane oxidation and the organisms responsible for the turnover of methane in the sediment, (2) prove the process of methane oxidation within the surrounding water column, and (3) verify the transport of sedimentary methane oxidizing microbes by gas bubbles through the collection of gas bubbles in different water depths.
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    In the year 2006, ICOS was recognized as an important research infrastructure by the Council of the European Union Research Ministers and it was added to the priority list (“roadmap”) of the European Strategy Forum on Research Infrastructures (ESFRI). ICOS aims to create an atmosphere, land and ocean monitoring network, able to reliably quantify sinks and sources of greenhouse gases and its catchment areas throughout Europe, and thus to identify and to document changes in the carbon cycle, for at least 20 years. ICOS allows to monitor and to assess the impact of human activities on the climate as well as the success and efficiency of avoidance and abatement strategies. The german component of ICOS (ICOS-D) is in its pilot phase since 2012. The entire installation of the monitoring network should be completed by 2016. In the framework of ICOS-D, the IOW further expands the required instrumentation installed on a ferry, operating on a regular and direct link between Travemünde and Helsinki (the FINNMAID, owned and operated by the shipping company Finnlines). Currently, hydrographical and biological basic parameters are being collected by the Finnish side (Project ALGALINE) whereas measurements of pCO2, pCH4 and oxygen content in the surface water are being conducted by the IOW. Being the only observation line established in a marginal sea, the „BALTIC-VOS“ line plays an important in connecting land and sea based observations in ICOS-D (VOS = voluntary observing ships). Due to anthropogenic impacts (eutrophication, warming), the already over decades documented changes in the Baltic Sea ecosystem are particularly strong and make this observation line especially suited to examine effects of a change in use or adopted environmental strategies on trace gas fluxes. Furthermore, it plays a key role in the development of a seagoing data acquisition system for the “Big Three” of trace gases relevant for the climate: CO2, CH4, N2O. Involved persons (IOW): Gregor Rehder (PI), Wanda Gülzow (project-funded scientist), Michael Glockzin (project-funded engineer).
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    “Ocean acidification” due to increasing atmospheric CO2 levels has become an important issue in chemical and biological oceanography. This refers in particular to the Baltic Sea which in most regions is characterized by a low buffer capacity. Thus the need for precise, accurate, and traceable pH measurements on a uniform and internationally accepted scale has gained importance during the last decades. Additionally, investigation and determination of the entire marine CO2 system are useful tools to study biogeochemical processes in the Baltic Sea. However, using pH for the calculations of the CO2 system requires a high accuracy and must refer to the “total” scale which is the basis for the currently best available dissociation constants. In the Baltic pH-monitoring was carried out during recent decades. Attempts were undertaken to detect trends in pH. But the results were ambiguous and revealed severe inconsistencies. To meet the demands for both effective monitoring and biogeochemical research, we propose to develop and to construct a flow-through pH measurement device suitable for continuous measurements on platforms such as VOS lines as well as for the measurement of discrete samples. The determination of the pH will be based on spectrophotometry using m-cresol purple as indicator dye. The method has been successfully applied to ocean waters. However, additional investigations are required to adapt spectrophotometric pH measurements to the specific hydrochemical characteristics of the Baltic Sea. The outcome of the project will be the development of a prototype system for accurate pH-measurements, investigations of chemical parameters and their theoretical and mathematical description and additionally the further hard- and software development. The project has a duration of 3 years (4/2014 - 3/2017), a budget of 415.000 €, and is funded by the EU and the national research councols of Germany, Poland, and Sweden. The project is coordinated by Prof Dr. Gregor Rehder (IOW). PINBAL is funded by the Bonus programme through the European Community's Seventh Framework Programme (FP/2007-2013) under implementation agreement n R&I/I3/2012/BONUS made with BONUS, the joint Baltic Sea research and development programme.

  • The service of sediments in German coastal seas – evaluating the function of marine benthic systems in the context of human use – Service functions of the Baltic Sea- (SECOS): WP 2.4 "Gas exchange at the sediment water interface"
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    Coastal and marginal seas operate as natural reaction sites for the processing and accumulation of land-derived discharges, e.g. nutrients, toxic substances, biotic/abiotic material. The main locations of accumulation as well as chemical/biological modification are almost the sediments. Surprisingly, their key position in the complex land-sea interaction is insufficiently studied and assessed so far. Within the framework of the BMBF-project SECOS („The service of sediments in German coastal seas“), the distribution and quantitative relevance of sedimentary services will be mapped and modelled in the range of the German Baltic Sea waters. Existing management tools for marine coastal systems will be improved, including human impacts and projections of future scenarios. This will be realised by the functional assessment of those sedimentary areas that are most relevant contributors to desired feedbacks to the environment and society. Thus, a first approach of a monetary “ecosystem service” assessment will be generated and all results will be presented in summarised habitat maps. Within the work package 2.4 “Gas exchange at the sediment- water interface”, fluxes of the greenhouse gases CH4, N2O and CO2 will be determined for key sediment types. This aims for a mechanistic understanding of the loss of CH4 and N2O from sediments as a first step towards implementation in the model framework. Therefore, modern analytic methods will be applied such as gas chromatography and mass spectrometry. The sampling will be performed at 20-30 m water depths with a benthic chamber lander system. A first ship cruise with “RV Alkor” is planned for March 2014.
  • (For details please klick here)
    ...under construction...
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    Methane is an important atmospheric trace gas with a relevant impact on earth’s climate. Although aquatic systems represent the most significant source of atmospheric methane, the importance of the marine system seems to be marginal. One effective mechanism that is limiting the flux of methane from the sedimentary reservoir into the atmosphere is the microbial oxidation of methane in the sediment. Compared to the number of studies on the microbial processes of methane oxidation in sediments, water column studies are scarce. Long-time stagnation periods within the deep basins of the central Baltic Sea (Gotland- and Landsort-Deep) have caused anoxic conditions in the deep water with strongly elevated methane concentrations. The transition zone between the oxic and anoxic water bodies (redoxcline) allows a systematic sampling of the water depth that is relevant for the turnover of methane. Thus, the detailed study of the microbial methane oxidation in the Gotland- and Landsort-Deep enables us to get new insights into the cycle of methane in the Baltic Sea that may can be used for a better understanding of the methane turnover in other anoxic/oxic basins in the world. In our multidisciplinary approach we (1) quantify the processes of the turnover of methane in the water column of the Gotland- and Landsort-Deep, (2) identify the organisms which are relevant for the turnover of methane in the water column and study their footprint in the sedimentary geological record, (3) integrate our results into hydrodynamic-biochemical numerical model.
  • (For details please klick here)
    Our objective in the third phase of the SPP is to determine the transport of methane, hydrogen and3-helium in the plumes originating from the Logatchev vent field on the Mid-Atlantic Ridge. We(IFM-GEOMAR and IOW) intend to conduct tow-yo CTD surveys of these dissolved gases within adistance of a few kilometers from these vents. We will combine this information with long-term currentmonitoring measurements that will be carried out by Fischer and Visbek (IFM-GEOMAR). The tow-yo surveys will be conducted at the beginning and at the end of the moored profiler/current metermonitoring, on F/S MERIAN cruises 06/2 and 10/3, in order to provide cross-sectional snap shots of the gas distributions in conjunction with these time-series records. Additional vertical CTD-rosette sampling stations will be placed along the 100 km length of the rift valley axis that starts from the 15°20’N Fracture Zone in order to obtain an estimate of the inventories of these gases in this segment. Methane and hydrogen will be measured on board these expeditions; helium isotope measurements will be conducted at the University of Bremen subsequently. We will also measure dissolved methane and hydrogen concentrations in the vent fluids collected during these expeditions, and we shall measure the methane 13C/12C ratio in all gas samples collected on these expeditions. We will be working with M. Perner on kinetic incubation experiments for the purpose of measuring hydrogen consumption rates due to the activity of bacteria found in the vent fluids.
  • (For details please klick here)
    BALTIC GAS aims to understand how climate change and long-term eutrophication affect the accumulation of shallow gas and the emission of methane and hydrogen sulfide from the seabed to the water column and atmosphere. The outcome of the project will be a new understanding and quantitative synthesis of the dynamics and budget of methane in the seabed, an important but poorly understood component of the Baltic ecosystem response to natural and human- induced impacts. The project aims to develop a predictive model of gas accumulation and emission under realistic scenarios of climate change and eutrophication, which will improve the knowledge base for necessary future policy actions. The multidisciplinary project will involve 12 partner institutions from 5 nations and will apply modern advanced technology and novel combinations of approaches.
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    Under construction...
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    The Gotland Deep Environmental Sampling Station (GODESS) is a profiling mooring, meaning that a profiling body with the payload (the instruments making measurements) is ascending and descending through the water column at predefined times or intervals. During a deployment of the mooring (typically between 3 and 6 months) repeated profiles of the measured parameters are registered so that we gain an insight of the changes and dynamics during this deployment period. A special interest for this station is the redoxcline in the Gotland Basin between the oxygenated surface layers and the anoxic deep layer.

Working group leader

Prof. Dr. Gregor Rehder



Dr. Oliver Schmale

Dr. Bita Sabbaghzadeh

Dr. Henry Bittig

Dr. Luiz Cotovicz Jr.

Dr. Teresa Morganti

Dr. Jannine M. Lencina Avila


Technical staff

Dr. Stefan Otto

Dipl.Ing. (FH) Michael Glockzin

Bernd Sadkowiak


PhD students

Daniel Pönisch

Malin Waern

Sören Iwe

H. M. Kusala M. Premaratne








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