|Zooplankton grazing in natural water with high concentration of 14C bicarbonate: variable live controls and gut passage time|
Baars, M.A.; Oosterhuis, S.S. (1985). Zooplankton grazing in natural water with high concentration of 14C bicarbonate: variable live controls and gut passage time. Hydrobiol. Bull. 19(1): 71-80
In: Hydrobiological Bulletin. Netherlands Hydrobiological Society: Amsterdam. ISSN 0165-1404, more
Digestion; Food intake; Food intake; Grazing; Ingestion; Measurement; Radioactive labelling; Zooplankton; Calanus finmarchicus (Gunnerus, 1770) [WoRMS]; Marine
|Authors|| || Top |
- Baars, M.A.
- Oosterhuis, S.S.
In grazing experiments with high concentrations of 14C bicarbonate in the medium, live controls were kept in the dark in filtered seawater with the radioisotope added. Calanus finmarchicus stages CIV - CVI females showed uptake of soluble tracer dependent on size. Radioactivity linearly increased with time and after 1 hour specific activities of the animals probably were not yet equal to that of the medium. During a bloom of Chaetoceros spp. radioactivity of the latter category of animals was much higher than that of the former, pointing to sincere adherence of labelled matter to mouthparts and body. Later, when Thalassiosira conferta and the flagellate Corymbellus aureus dominated, no such differences were found. Variable results in these changing field conditions also occurred in experiments with grazing periods ranging from 5 to 75 min. Sharp drops in animal radioactivity were observed between 15 and 30 minutes after the start of feeding on prelabelled water in the Chaetoceros period, probably due to the egestion of the first radioactive faecal pellets. During the Corymbellus period filtering rates were much lower and animal radioactivity linearly increased up to 60 or 75 min.