Climate change induced shift in cyanobacterial mat species (psychro-tolerant - thermo-tolerant) in Antarctica and in cyanobacterial blooms in New Zealand
Zusammenfassung der Projektergebnisse
Cyanobacteria, especially from more temperate regions, are known to produce different toxic secondary metabolites and become problematic for human health when major blooms occur in fresh and saltwater bodies. The first part of the project was capable of demonstrating that cyanobacterial toxins are produced rather dynamically in a short time period and thus these preliminary data may indicate that these toxins are quorum-sensing molecule for cyanobacteria. The second part of the project was able to demonstrate that cyanobacterial cells as well as toxins are aerosolized from cyanobacterial blooms in freshwater lakes and thus provide for a human inhalatory exposure. The quantification of this exposure and thus the preliminary assessment of these data however suggest that the inhalatory exposures even when occurring chronically should not provide for an increased human health hazard. The third project dealt with the occurrence and diversity of cyanobacteria in polar-regions. Cyanobacteria are the main primary producers in the terrestrial (and on-ice) Arctic and Antarctic regions, where they occur in thick benthic mats in ponds, streams and lakes, that are inhabited by a large variety of metazoan species (e.g. nematodes, tardigrades, rotifers). However, diversity, dispersal and community structure in the polar-regions are still poorly understood. Mat communities from different Arctic and Antarctic locations were described at the level of species diversity and toxin production. In addition the effect of increased temperature on the capability of these mats to produce toxins was investigated. The preliminary assessment of cyanobacterial mats demonstrated a large heterogeneity with regard to species diversity amongst cyanobacterial mats occurring at nearby locations. Generally cyanobacterial mats of the Antarctic appeared more diverse than those of the Arctic. Toxin analysis demonstrated for the first time that Arctic cyanobacteria produced toxins and, although this cannot be generalized, that increased temperature could provide for a stimulus to produce higher concentrations of toxins. Moreover, first experiments in a flow-through biofilm chamber suggest that the production of toxins could influence cyanobacterial mat diversity. Generally speaking above experiments are a first step toward understanding of the effects of a small temperature increase (thus climate change) on cyanobacterial growth and toxins production and could provide for an improved understanding of cyanobacterial bloom dynamics and toxin production also in more temperate climates and freshwater bodies used for drinking water.
Projektbezogene Publikationen (Auswahl)
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(2010): Cyanobacterial Diversity and Toxin Production in Arctic and Antarctic Freshwater Ecosystems IPY Oslo Science Conference 2010, June 6-12, 2010, Oslo, Norway
Kleinteich, J., Quesada, A., Camacho, A., Küpper, F.C., Wood, S.A., and Dietrich, D.R.
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(2010): Quantitative assessment of aerosolized cyanobacterial toxins in two New Zealand lakes. 49th Annual Meeting of the Society of Toxicology, March 7-11, 2010, Salt Lake City, USA
Wood, S.A., and Dietrich, D.R.
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(2010): Switching toxin production on and off: intermittent microcystin synthesis in a Microcystis bloom, Environ. Microbiol. Reports
Wood, S.A., Rückert, A., Hamilton, D.P., Cary, S.C., and Dietrich, D.R.
