Grazing ofEuphausia superbaDana on natural phytoplankton populations

✍ Scribed by M. A. Meyer; S. Z. El-Sayed

• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 483 KB
• Volume: 1
• Category: Article
• ISSN: 0722-4060
• DOI: 10.1007/bf00443187

✦ Synopsis

Euphausia superba (krill) has been suggested from stomach content analysis (Nemoto 1971(Nemoto /1972) and from the comparison of krill and phytoplankton species distribution (Kawamura 1981). Laboratory experiments can help determine whether krill selectively graze certain phytoplankton species. Grazing experiments were conducted at Palmer Station, Antarctica, during the austral summer 1977/1978. Krill, collected from waters surrounding the Antarctic Penninsula, were maintained in flow-thru aquaria at Palmer Station. E. superba were added to glass bottles (4.48 1), containing 220 ~tm mesh filtered sea water. Bottles, with and without krill, were incubated in the dark at sea surface temperature, for two to twenty-seven hours. End point determinations were made for phytoplankton cell number. The cell counts were divided into size and species categories, and the calculated filtering rates were compared through analysis of variance. These experiments led to the conclusion that krill "selectivity" for phytoplankton species is probably size dependent, with solitary cells smaller than 20 ~m (maximum diameter) being filtered less rapidly than larger diatoms and chain forming species.