Expansion of new toxic dinoflagellate blooms in the Baltic Sea: sensitivity to environmental change and ecosystem consequences


Recent evidence suggests a growing role of toxic dinoflagellates in the planktonic ecosystem of the Baltic Sea. Alexandrium ostenfeldii (Paulsen) Balech et Tangen is presently the most dramatically expanding species, which produces potent neurotoxins (spirolides and PSP toxins). The Baltic blooms have been exceptionally dense with cell concentrations far exceeding reported values elsewhere. This project investigates the causes and mechanisms of the recent spreading and bloom formation of A. ostenfeldii in coastal northern Baltic waters. Our objectives are:

  1. to analyze the spreading pattern to and within the Baltic Sea, and thereby determine if the species  has invaded or simply become more abundant;
  2. perform field surveys on the population dynamics and distribution patterns in relation to environmental parameters to better understand the role of changing environmental conditions in the expansion;
  3. examine the role of specific ecophysiological adaptations, such as resting cyst formation, mixotrophy and allelopathy in the success of the species; and
  4. study genetic and physiological diversity and the potential of the local A. ostenfeldii populations to adapt to environmental pressures imposed by climate change and eutrophication. 

The other objective of this project is the assessment of the risk which toxic dinoflagellate pose on the northern Baltic ecosystem. We study the occurrence of dinoflagellate toxins in the food web and examine the effects they have on higher trophic levels and the pelagic food web. The generated knowledge will facilitate a better prediction of toxic Alexandrium blooms in coastal waters and provide a realistic assessment of their risks to the environment and human health.

More information

Dr. Anke Kremp, senior researcher, Finnish Environment Institute SYKE, firstname.surneme@ymparisto.fi

Published 2013-04-24 at 10:02, updated 2013-04-24 at 12:18

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