On the nutrition and metabolism of zooplankton. VIII. the grazing of Biddulphia cells by Calanus helgolandicus

Abstract

The rations removed by adult and stage V Calanus helgolandicus (Claus) feeding on large cells of the diatom Biddulphia sinensis Grev. were measured using an apparatus especially designed to keep the plant cells in suspension and estimated to reach a maximum of 1800 cells/animal/day at a food concentrationof 11,300 cells/1. A continual flow method was used to study feeding at very low algal concentrations and it was found that the animals still captured Biddulphia at a food level of only 270 cells/1.The animals in the feeding experiments were used at a very low population density (6 copepods/1350 ml.) and the maximum value found for the volume of sea water swept clear – 700 ml./animal/day - was unusually high.The maximum daily rations consumed by each animal were also high, being equivalent to 47–5 % of the body nitrogen and 46–4 % of the body phosphorus. The number of faecal pellets released by the animals increased with the size of ration captured, but the percentage of the ration lost as faecal pellets was fairly constant. In terms of dietary nitrogen the average value was 65–9% and that for dietary phosphorus 59·6%.The percentage of the daily ration of nitrogen excreted in soluble form was 266% and that of phosphorus 41–2%, these values being significantly higher than those found using unfed animals. Nearly 90 % of the nitrogen excreted by the animals, whether feeding or unfed, was in the form of ammonia. The amounts of excreted ammonia and total soluble phosphorus increased significantly when the animals fed; but the small quantities of nitrogen released in forms other than ammonia did not change.

Inefficient feeding by Calanus helgolandicus and Temora longicornis on Coscinodiscus wailesii: quantitative estimation using chlorophyll-type pigments and effects on dissolved free amino acids

“…Total debris production due to copepod grazing (corrected for debris present in the control bottles) represented 26 % of pigments in cells removed from the flasks for Calanus helgolandicus and 35 YO for Temora longicornis. These losses are somewhat larger than those calculated by Conover (1966) Corner et al (1972), studying C. helgolandicus feeding on the diatom Biddulphia sinensis, found no evidence of damage to these cells outside the copepod, and no loss of soluble nitrogen and phosphorus was observed. However, B. sinensis has significantly smaller cells (100 X 4 pm) than those used in our experiments.…”

Ontogenetic change of foraging behaviour during copepodite development of Acartia clausi

“…(Reeve & Walter 1977, Kiørboe et al 1985, Paffenhöfer & Stearns 1988 Vertical bars are ± SD al. 1992), as well as in other calanoid copepods (Corner et al 1972, Frost 1975, Frost et al 1983, Price & Paffenhöfer 1986, Paffenhöfer 1988. In A. tonsa, the lower feeding rate -below the threshold -is the result of a decrease in mouthpart movements (time spent feeding) and a lower fraction of encountered cells being captured (Paffenhöfer & Stearns 1988).…”

Zooplankton grazing and growth: Scaling within the 2‐2,‐μm body size range

“…Gaines unpubl. Hansen 1992Jeong and Latz 1994Jacobson and Anderson 1993Strom 1991Strom and Buskey 1993Anderscn 1988/l 989 Fenchel 1982Geider and Leadbeatcr 1988Rivier et al 1985Jonsson 1986Sheldon et al 1986Verity 1985 Verily 199 1 Boraas I983 Droop and Scott 1978Hansen et al 1997Schltiter et al 1987Scott 1980Helm 1977Jespersen and Olsen 1982Sprung 1983Sprung I984d Berggreen et al 1988Corner et al 1965Corner et al 1967 with an scaling exponent broadcast spawners.…”