ISSN:
1432-1793
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Clearance, ingestion and incorporation rates of the copepod Acartia tonsa were measured using the diatom Nitzschia closterium and Fucus vesiculosus detritus. Mean clearance rates ranged from 1.5 to 3.7 ml copepod-1 day-1 on N. closterium and from 1.6 to 5.3 ml copepod-1 day-1 on 28 day-aged F. vesiculosus detritus. The copepods ingested from 0.05 to 0.29 μgC μg copepod C-1 day-1 feeding on N. closterium and from 0.06 to 0.81 μgC μg copepod C-1 day-1 on 28 day-aged F. vesiculosus detritus. N. closterium (4 to 6 μm diameter) is at the lower size limit of retention efficiency of A. tonsa as compared to the F. vesiculosus detritus used (10 to 24 μm diameter). Therefore, the greater feeding rate of A. tonsa on detritus was probably due to greater particle size. Relative levels of incorporation efficiency measured over several food concentrations ranged from 18 to 55% for P32-labelled N. closterium and 10 to 45% for 28 day-aged Zn65-labelled F. vesiculosus detritus. Incorporation rates of A. tonsa fed differently aged F. vesiculosus (0, 14, 28 and 56 days) ranged from 2.92 μg F. vesiculosus μg copepod-1 day-1 for unaged detritus to 0.06 μg F. vesiculosus μg copepod-1 day-1 for 56 day-aged F. vesiculosus detritus. Although the percent nitrogen of the detritus increased with age, A. tonsa had a greater incorporation rate on fresh detritus, which had a larger mean particle diameter than older detritus. As both P32 and Zn65 are not as metabolically labile as carbon, incorporation rates are probably underestimates of the true values. While A. tonsa was able to grow and reproduce on N. closterium, they did not survive on variously aged F. vesiculosus detritus. Cannibalism occurred in the A. tonsa cultures, so growth results are relative.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00391565
