This two-year award will support U.S.-Sweden cooperative research on the history of cyanobacterial blooms in the Baltic Sea between Thomas S. Bianchi of Tulane University and Ragnar Elmgren of Stockholm University. The objective of their research is to determine through paleoecological methods, the long-term record of cyanobacterial blooms in the Baltic Sea. They will use marker pigments from fossils, siliceous microfossils and biogenic amorphous silica to determine past phytoplankton assemblages. Petrogenic components and radionuclides will be used to determine sedimentation rates and resuspension events. Dr. Bianchi brings to this collaboration expertise in biomarkers as tracers of carbon. This is complemented by Swedish expertise in eutrophical studies in the Baltic and in geochemical assessment of sediments. Increased nutrient loading over the past four decades in the Baltic Sea has resulted in significant eutrophication problems. While there has been a concerted effort in recent years to control nutrient inputs, many problems still exist. For example, cyanobacterial blooms proliferate in the summer and the causes of these blooms remain largely unknown. The project will advance our understanding of why these blooms occur and whether they are a natural phenomena of the Baltic Sea that are not necessarily associated with anthropogenic inputs. Information about the origins of cyanobacterial blooms and the effects on long-term nutrient limitations will contribute to the development of an environmental management plan for the Baltic Sea.
