|Particle selection in filter-feeding bivalve molluscs: a new technique on an old theme|
Shumway, S.E.; Newell, R.C.; Crisp, D.J.; Cucci, T.L. (1990). Particle selection in filter-feeding bivalve molluscs: a new technique on an old theme, in: Morton, B. (Ed.) The Bivalvia: Proceedings of a Memorial Symposium in honour of Sir Charles Maurice Yonge (1899-1986) at the 9th International Malacological Congress, 1986, Edinburgh, Scotland, UK. pp. 151-165
In: Morton, B. (Ed.) (1990). The Bivalvia: Proceedings of a Memorial Symposium in honour of Sir Charles Maurice Yonge (1899-1986) at the 9th International Malacological Congress, 1986, Edinburgh, Scotland, UK. Hong Kong University Press: Hong Kong. ISBN 962-209-273-X. 355 pp., more
|Authors|| || Top |
- Shumway, S.E.
- Newell, R.C.
- Crisp, D.J.
- Cucci, T.L.
The efficiency of particle retention from algal suspensions, and its significance in the estimation of energetics of growth has been widely studied in bivalve molluscs. Whether filter-feeding organisms can (1) select; (2) preferentially ingest, and/or (3) preferentially digest suspended particles, is of major importance to our understanding of material flow through marine systems. The complex size overlap presented by natural populations of phytoplankton in the sea which once limited the scope and design of experiments on the differential utilization of particulate matter have been at least partially overcome through the use of flow cytometry. Until recently, investigations have been limited by the lack of techniques that can distinguish quantitatively between different particles of the same size. The methods are now available and by taking advantage of fluorescence and light scatter characteristics of particles, we have been able to examine differential use by consumer organisms of food resources, even when those resources are comprised of groups having similar sized cells. Using this technique, we have been able to estimate not only the clearance rate of individual cell types, but also their proportional occurrence in the pseudofaeces and faeces. In addition, bacteria can now be used experimentally, provided they have been stained with fluorescent materials prior to use. Through the use of flow cytometry, we have been able to demonstrate three different mechanisms of selection which may be present in isolation or in combination in filter-feeding bivalve molluscs: (a) preferential clearance on the ctenidia; (b) preingestive selection on the labial palps and (c) differential absorption in the gut. Flow cytometry thus presents a potentially manageable, sensitive and unified approach to the study of interrelated problems of particle selection, food preferences and material flow in marine organisms previously not approachable. This technique, coupled with other newly devised methods, allows investigators to carry out more complex feeding studies using a number of particles simultaneously, and will allow us to elucidate at least some of the mechanisms involved in particle selection in filter-feeding animals.