NEWS The twelve mesocosms at Umeå Marine Sciences Centre are running at full speed. During five weeks experiments are performed by a research team led by Erik Björn and Agneta Andersson, Umeå University. They are hoping to find out how humic substances influence the accumulation of methyl mercury in the marine food web.
-Earlier experiments have shown that a climate change-related increase in humic substances can lead to a significant increase in concentrations of methyl mercury in zooplankton. We want to test three scenarios with levels of humic substance concentrations, and at the same time try to characterize the food web in detail, says Erik Björn.
The background to the research is that climate change is expected to lead to an increased transport of humic substances from land to sea. An increased concentration of humic substances in the seawater impairs the conditions for phytoplankton. Instead, the growth of bacteria will be favoured. A food web dominated by bacteria generally includes a larger number of steps, and thereby presumptive larger concentrations of mercury in the organisms at higher levels of the food web. In other words, zooplankton and fish probably will contain more mercury in the climate changed future.
Editor: Kristina Viklund