Nodularin concentrations in Baltic Sea zooplankton and fish during a cyanobacterial bloom

• Published in: Marine biology 2008-10, Vol.155 (5), p.483-491
• Main Authors: Karjalainen, Miina, Pääkkönen, Jari-Pekka, Peltonen, Heikki, Sipiä, Vesa, Valtonen, Terhi, Viitasalo, Markku
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biomedical and Life Sciences; Cells; Cladocera; Community; Copepoda; Decapoda; Eurytemora affinis; Fish; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; Life Sciences; Marine; Marine & Freshwater Sciences; Marine biology; Microbiology; Nodularia spumigena; Oceanography; Original Paper; Phytoplankton; Plankton; Pleopsis polyphemoides; Sea water ecosystems; Synecology; Toxins; Trophic levels; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Waterfowl; Zoology; Zooplankton
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-008-1046-4

Toxic cyanobacterial blooms, dominated by Nodularia spumigena , are a recurrent phenomenon in the Baltic Sea during late summer. Nodularin, a potent hepatotoxin, has been previously observed to accumulate on different trophic levels, in zooplankton, mysid shrimps, fish as well as benthic organisms, even in waterfowl. While the largest concentrations of nodularin have been measured from the benthic organisms and the food web originating from them, the concentrations in the pelagic organisms are not negligible. The observations on concentrations in zooplankton and planktivorous fish are sporadic, however. A field study in the Gulf of Finland, northern Baltic Sea, was conducted during cyanobacterial bloom season where zooplankton (copepod Eurytemora affinis , cladoceran Pleopsis polyphemoides ) and fish (herring, sprat, three-spined stickleback) samples for toxin analyses were collected from the same sampling areas, concurrently with phytoplankton community samples. N. spumigena was most abundant in the eastern Gulf of Finland. In this same sampling area, cladoceran P. polyphemoides contained more nodularin than in the other areas, suggesting that this species has a low capacity to avoid cyanobacterial exposure when the abundance of cyanobacterial filaments is high. In copepod E. affinis nodularin concentrations were high in all of the sampling areas, irrespective of the N. spumigena cell numbers. Furthermore, nodularin concentrations in herring samples were highest in the eastern Gulf of Finland. Three-spined stickleback contained the highest concentrations of nodularin of all the three fish species included in this study, probably because it prefers upper water layers where also the risk of nodularin accumulation in zooplankton is the highest. No linear relationship was found between N. spumigena abundance and nodularin concentration in zooplankton and fish, but in the eastern area where the most dense surface-floating bloom was observed, the nodularin concentrations in zooplankton were high. The maximum concentrations in zooplankton and fish samples in this study were higher than measured before, suggesting that the temporal variation of nodularin concentrations in pelagic communities can be large, and vary from negligible to potentially harmful.