Effects of diatom diets on the reproduction of the planktonic copepod Calanus finmarchicus
Starr, M.; Runge, J.A.; Therirault, J.-C. (1999). Effects of diatom diets on the reproduction of the planktonic copepod Calanus finmarchicus. Sarsia 84: 379-389
In: Sarsia. University of Bergen. Universitetsforlaget: Bergen. ISSN 0036-4827; e-ISSN 1503-1128, more
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| Authors | | Top |
- Starr, M.
- Runge, J.A.
- Therirault, J.-C.
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| Abstract |
The potential for an adverse influence of diatom diets on the reproductive success of the planktonic copepod Calanus finmarchicus was investigated experimentally under laboratory conditions. A monospecific diet of the common diatom Thalassiosira nordenskioldii significantly reduced the viability of Calanus eggs, which either failed to hatch or hatched into deformed nauplii. The production of nonviable eggs increased with increasing Thalassiosira concentration and was proportional to the female ingestion rate. At a cell concentration of 10 4 ml Ð1 (typical bloom concentration in the St. Lawrence Estuary), the proportion of nonviable eggs was as high as 83 % of the total daily production. Nonviable egg production was also induced by a diatom of the genus Navicula, but not by two other diatoms, Skeletonema costatum and Chaetoceros debilis. Among non-diatom diets, maternal feeding on a dinoflagellate (Prorocentrum micans) and two flagellates (Isochrysis galbana, Pavlova lutheri) at food-saturated conditions resulted in the production of normal eggs, more than 70 % of which hatched into healthy nauplii. The hatching success of eggs was independent of the daily egg production rate, as only three of the algal species (T. nordenskioldii, S. costatum, and P. micans) supported maximum egg production at superabundant food concentrations. A failure of embryonic development also occurred when females were exposed to a diversified diet composed of Thalassiosira, Chaetoceros and Skeletonema, even though T. nordenskioldii contributed less than 60 % of total ingested carbon. We conclude from these experiments that extended feeding on certain extremely common diatom species, by themselves and apparently also in mixtures where they predominate, could have a negative impact on C. finmarchicus recruitment rates. |
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