Person in charge: Anke Kremp

Other persons: Sanna Suikkanen, Johanna Oja

Financiers: Academy of Finland

Summary

Phytoplankton algae form seasonal blooms which fuel aquatic systems. In variable environments like the Baltic Sea, conditions in the water support algal growth only for short periods of time. Many species enter dormancy and spend adverse conditions resting in the sediments at the sea floor. The sediments integrate individuals and species over time and form a genetic reservoir, equivalent to seed banks of higher plants. Such reservoirs are expected to function as buffers against environmental variability. Here we investigate how the diversity reservoir supports the capacity of Baltic algae to deal with environmental change. The project characterizes resting stage diversity of the benthic seed banks using modern sequencing approaches, and examines the relationship between seed banks and phytoplankton stability in lab experiments and long term data analyses. This project will contribute to a better assessment of the resilience of Baltic plankton under conditions of ongoing environmental change.

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https://cordis.europa.eu/project/rcn/195794/reporting/en

Person in charge: Anke Kremp

Other persons: Conny Sjöqvist, Johanna Oja

Financiers: Academy of Finland Research Fellowship

Partners: University of Gothenburg (Sweden), Lund University (Sweden), Technical University of Denmark, Japanese Fisheries Research Agency

Summary

Person in charge: Anke Kremp 

Summary

Pelagic microalgae (or phytoplankton) are primary producers and form the base of the aquatic food web. Consequently they have a major impact on the food web, energy flow and biogeochemical cycles. Some microalgae can also form harmful blooms which can lead to substantial economic losses and health issues by causing toxicity of mussels, fish kills, odors, unattractive water color, or by making freshwater unsuitable as drinking supply. Populations of harmful algae are genetically highly structured and may show remarkable differentiation among and within local populations. Diversity patterns may indicate colonization and invasion patterns, reveal mechanisms of adaptation and speciation and provide insights into the evolutionary history of phytoplankton species in relation to environmental change. 

The aim of the proposed Nordic network is to foster collaboration in the ongoing studies on patterns, mechanisms the ecological consequences of intra-specific diversity of aquatic photosynthetic protists. We will compare phytoplankton species and populations from different taxonomic groups and habitats spanning from freshwater lakes to the brackish Baltic Sea and North Atlantic waters. This will advance the general understanding of population genetic, ecological and evolutionary principles in aquatic protists which are still poorly known compared to other organism groups. During the 3 years of the network we will share materials, methods and instrument facilities, perform joint surveys and experiments, exchange knowledge and expertise, integrate information and offer joint training possibilities for PhD students and post-docs (workshops and lab visits). This will support the development of research on the subject of protist diversity in the Nordic countries considerably and facilitate solid future cooperation.

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Person in charge Anke Kremp

Other persons Sanna Suikkanen, Outi Setälä, Pia Mäenpää, Päivi Hakanen, Sari Lehtinen

Summary

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. ostenfeldiiin 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.

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