|Biochemical studies on the production of marine zooplankton|
Corner, E.D.S.; Cowey, C.B. (1968). Biochemical studies on the production of marine zooplankton. Biol. Rev. 43: 393-426
In: Biological Reviews. Cambridge Philosophical Society: Cambridge. ISSN 1464-7931, more
|Authors|| || Top |
- Corner, E.D.S.
- Cowey, C.B.
1. Phytoplanktonic algae vary in their value as food for zooplankton and no single algal food can meet the full nutritional needs of zooplanktonic animals. Perhaps this is because optimal amounts of essential micronutrients are not all present in any one alga. The dietary requirements of planktonic Crustacea, as far as they are known, bear some resemblance to those of vertebrates.2. The proteins of phytoplankton are similar in amino acid composition to those of zooplankton. This circumstance should favour efficient synthesis of protein by the animal, for assuming amino acids are all released in the gut and absorbed at approximately the same rate, they will be presented to the tissues in roughly the right relative amounts for protein formation.3. Zooplankton are able to alter the characteristics of the fatty acids present in their diet by elongating the carbon chain length and by increasing the degree of unsaturation.4. Measurements of phosphorus and nitrogen excretion indicate that zooplankton are metabolically very active. Some of the very high rates of phosphorus excretion are questioned and it is suggested that some portion of the phosphorus compounds liberated by zooplankton have passed straight through the gut without being assimilated. It is unlikely that all forms of organically bound phosphorus are equally rapidly assimilated and turned over by zooplankton.5. Estimates of the rate of ammonia excretion by zooplankton differ markedly. This may be a matter of size/surface area of the animals concerned—smaller animals excreting more rapidly than larger animals. It has been claimed that a-amino nitrogen is released in considerable quantities by zooplankton but the evidence is not yet compelling.6. There is considerable disagreement on the efficiency of food assimilation and conversion by zooplankton. One view is that irrespective of the quantity of phyto-plankton ingested assimilation is uniformly high. The opposing view holds that when rapid ingestion of phytoplankton occurs the percentage assimilated falls. More information on the feeding behaviour of zooplankton and on the physiology of their digestive processes is required before this controversy can be satisfactorily resolved.