Grazing rates in relation to food supply.

RIEBESELL, U., SCHIEL, S., SCHLOSS, I.R.

Berichte zur Polarforschung Reports on Polar Research

Alfred-Wegener-Institut

Año: 1989 p. 160 - 164

Zooplankton is exposed to a great variety of food organisms andconcentrations. Both the abundance and size of food particles influencefeeding rates. Preferential grazing On certain size classes of phytoplanktoncan lead to an alteration of the phytoplankton species composition.Euphausiids and many copepods, for example, feed most efficiently Onlarger particles, thereby changing both the cell size spectrum and,consequently, the phytoplankton species composition in the direction ofsmaller species. With decreasing food abundance, however, selectivefeeding becornes less important.The general scope of this study is to gain a deeper understanding of thefeeding behaviour of the Krill Euphausia superba and the dominantcopepod species in Antarctic waters. Specific objectives were to determine,for different species of copepods and different size classes of Euphausiasuperba., the following:1) the relationship between particle size and feeding rates, and2) the effect of decreasing concentrations of various sizes of food particlesOn feeding rates