Spring has begun in the sea – R/V Aranda's cruise begins

11.4.2012 9:16

Researchers from the Finnish Meteorological Institute (FMI) and the Finnish Environment Institute (SYKE) set out after Easter on a research cruise to the Gulf of Finland and the Baltic Proper to investigate the importance of the algal bloom to the capture of carbon and nutrients.

Photo: Stefan Simis

Photo: Stefan Simis

During the ten-day cruise measurements and samples for research that supports the development of models that describes the impact of climate change are taken. The material will also be used for improving the interpretation of satellite observations of algal blooms.

While the remote parts of the Baltic Sea are still frozen over, spring has already started to colour the waters green in the south. The short-lived spring bloom of marine algae will progress north and grow in the cold waters as soon as sunlight, and for as long as nutrients, are available.

The oceans are an important sink for the carbon dioxide released to the atmosphere but the increasing carbon dioxide also leads to the acification of the seas. The exchange of the carbon dioxide between the sea and the atmosphere is not yet well understood and consequently affects the accuracy of climate and ecosystem models. Physical oceanographers of FMI will collect data to study the exchange processes and especially the role of waves in the carbon dioxide exchange during this biologically active season. SYKE ecologists measure the uptake of nutrients and the use of the still scarcely available sunlight for photosynthesis. Eventually, they aim to formulate accurate models of the sea ecosystem, that predict what will happen to the marine food web in a changing climate. Also, the measurements will be used to improve the interpretation of the satellite images that are used to monitor the algal blooms in the nutrient-rich Baltic Sea.

When the spring bloom subsides, the sea clears up for a short spell while zooplankton grazes and bacteria digest the first algae harvest of the year. What they don't catch, will sink to the bottom. Scientists from SYKE will take sediment samples from the sea-floor to study biogeochemical cycling of phosphorus in the open Baltic Sea. Samples will be analysed to examine sediment properties that affect phosphorus binding to the seafloor or, in contrast, its release from sediments to the water.

Further information:

Air-sea interaction studies: chief scientist, senior scientist Heidi Pettersson, FMI, tel. 040 5601534
Ecological studies, algal blooms: senior research scientist Stefan Simis, SYKE, tel. 040 1823319
Sediment chemistry: senior research scientist Kaarina Lukkari, SYKE, tel. 040 1823249

Chief editor, Web services Aira Saloniemi
SYKE´s communications, Baltic Sea issues
Tel. 0400 148875