The seas cover more than 70% of the surface of our planet, and hosts a great variety of habitats – e.g. artic ice landscapes, Baltic Sea archipelagos, tidal flats, coral reefs and trenches deeper that Mount Everest is high. Off shore areas are sometimes referred to as marine deserts due to their low productivity, but with their vastness it is where most of the marine production takes place. The sea’s variable environment is the home of a fascinating biological diversity from microbes and plankton to fish and whales. Understanding the processes in the sea and its regulating factors is a prerequisite for a global understanding of ecology and environment. Research at our department addresses both basic and applied science, with a focus on the Baltic Sea, but also with research on the Swedish west coast, Africa, Central America and Southeast Asia.
Research areas with contact people
Nutrients and Eutrophication
Without nutrients (nitrogen and phosphorus) there would be no life in the sea. Nutrients are used by plants to produce the organic matter that constitute the basis of the food webs. To understand the “functioning” of the sea, we thus need knowledge on nutrient dynamics and regulation. In many areas, humans have increase nutrient concentrations in the sea (eutrophication) and this may have resulted in unwanted impacts like nuisance algal blooms and “dead bottoms” (areas with little or no oxygen)
Contact person: Sven Blomqvist
The SEABASED Project (Seabased Measures in Baltic Sea Nutrient Management)
The goal of the SEABASED Project was to reduce the consequences of eutrophication in the Baltic Sea. The project piloted and assessed measures that seek to improve the status of the selected sea bays by reducing the internal load of the sea. Some of the measures can also support the circular economy by recycling nutrients from sea to land. In the project recycling of the nutrient-rich water for irrigation of fields, binding of phosphorus in the seabed sediment by using natural, limestone-based material (heat-treated marl) and fishing stickleback to enhance predatory fish populations were piloted in Finland, Åland and Sweden. In addition, artificial reefs, and instructions for making a pike factory, a wetland to enhance pike populations, were made in Sweden, and a concept for aquatic compensations was designed, related to the renovation of the Water Act in Åland. The potential of sediment top-layer removal for phosphorus uptake and reducing the oxygen demand in the bottom was studied with incubation tests in laboratory scale.
The SEABASED Project engaged various stakeholders of the society in an open dialogue on the benefits and risks of the measures, and their applicability for the Baltic Sea, and produced information on the feasibility, risks, monitoring, cost-effectiveness, and development needs of different sea-based measures aiming to reduce the internal nutrient load in the sea. The knowledge along with practical experiences was compiled into Practical Guidelines to help Baltic Sea protection in the future. The guidelines are available via this link.
The SEABASED Project was carried out in 2018-2021. The project was led by the John Nurminen Foundation and project partners were the Centre for Economic Development, Transport and the Environment for Southwest Finland, Government of Åland, the Åland Fishfarmers’ Association, Stockholm University and County Administrative Board of Östergötland. The project was co-financed by the EU Interreg Central Baltic Programme.
The results from the field pilots along with other material produced by the SEABASED Project are available on the project’s website. The work by DEEP at Stockholm University in the SEABASED project was coordinated by Sven Blomqvist and Eva Björkman.
Food webs and fisheries
Plants and animals interact in various ways, and complex food webs result when some species feed on other. Humans interact in these food webs through different mechanisms. Eutrophication increases the plant production, which can favor some plants on the expense of other. Indirectly this influences also the fauna. Humans may impact these food webs also by massively killing certain species of animals (=fishing).
Contact person: Sture Hansson
Long term ecological research (LTER) in the Baltic Sea
The very basis to understand marine ecosystems and their dynamics are quantitative data of high quality, on nutrient concentrations and plant and animal abundances. Data on temperature, salinity and other environmental conditions are also needed. In our LTER projects we collect this kind of information from both the water and the bottoms, and from coastal as well as off shore areas. Some types of samples are collected year around (20 times/year) and some sampling programs started 40 years ago.
Contact person: Jakob Walve
Ocean colour remote sensing and bio-optical observations
Remote Sensing provides us with synoptic data of the whole Baltic Sea basin which helps to improve our understanding of phytoplankton blooms. The advantage of remote sensing is its improved spatial and temporal resolution which makes it a good complement to conventional monitoring methods
Contact person: Susanne Kratzer
Open ocean nitrogen (N) cycling
Open ocean nitrogen (N) cycling with an emphasis on N2 fixing microorganisms: free-living and symbiotic cyanobacteria. We focus on the activity, distribution, diversity, and interactions between the N2 fixing cyanobacteria and their environment and/or their respective hosts
Contact person: Rachel Foster
Seagrass and marine ecosystems
Multidisciplinary approach to coastal seas, focus on intertidal zone, seagrass, fisheries, mapping, women and natural resource management.
Contact person: Lina Mtwana Nordlund
Ecosystem-based management of the Baltic Sea
Baltic cyanobacterial blooms and Baltic benthos.
Contact person: Ragnar Elmgren
