Koski, M. University of Helsinki, makoski@touko.helsinki.fi
Engstrom, J. University of Helsinki, jonna@engstrom@helsinki.fi
Viitasalo, M. University of Helsinki, markku.viitasalo@helsinki.fi

 
THE EFFECT OF BLUE-GREEN ALGAE ON EGG PRODUCTION AND HATCHING SUCCESS OF A CALANOID COPEPOD EURYTEMORA AFFINIS
 
Egg production, hatching success and carbon and nitrogen content of a calanoid copepod Eurytemora affinis were measured in five concentrations (ca 50, 100, 200, 400 and 600 mg C l-1) of toxic and non-toxic blue-green algae Nodularia sp. and green algae Brachiomonas submarina. In addition, females with egg-sacs were collected from the sea and exposed to different concentrations of Nodularia sp., to find out if blue-green algae disturb hatching of eggs produced in natural (food) conditions. With B. submarina, copepod egg production was high (ca 7 eggs f-1 day-1), and increased with increasing food concentration, while with both toxic and non-toxic Nodularia sp. egg production was comparable to that in filtered sea water (0-2 eggs f-1 day-1), irrespective of food concentration. With both Nodularia sp. strains copepods produced deformed egg-sacs, and hatching success was low, while eggs produced in natural conditions hatched generally well. In experiments with toxic Nodularia sp. carbon and nitrogen content of E. affinis was low and mortality high, but with high concentrations of non-toxic Nodularia sp. mortality was low, and carbon and nitrogen content high. Our results suggest that copepods were able to survive with non-toxic Nodularia sp. if it was offered in high concentration; however, this species did not support copepod egg production.
 
Day: Wednesday, Feb. 3
Time: 11:00 - 11:15am
Location: Hilton of Santa Fe
 
Code: SS21WE1100H