Hostname: page-component-77c89778f8-rkxrd Total loading time: 0 Render date: 2024-07-22T19:19:17.131Z Has data issue: false hasContentIssue false

Molluscan grazing of sublittoral algal-bored shells and the production of carbonate mud in the Firth of Clyde, Scotland

Published online by Cambridge University Press:  06 July 2012

George E. Farrow
Affiliation:
Department of Geology, University of Glasgow
Julian Clokie
Affiliation:
Department of Botany, University of Glasgow, Marine Station, Millport, Isle of Cumbrae

Synopsis

The limpet Acmaea virginea is an important agent of erosion of bivalve shells within the photic zone. This lower limit is governed by the depth range of shell-boring algae on which it feeds, the dominant alga being conchocelis. Any authigenic ferromanganese coatings on shells are removed by the grazing and the shells may become wafer thin and highly fragmented. The chiton Lepidopleurus also grazes shell surfaces but feeds more on superficial detritus than on the boring algae, and so its depth range is not so restricted. Both molluscs leave highly distinctive radula marks on shells which are potentially preservable in the fossil record. Acmaea virginea produces broad scoops, six-pronged, with very sharp narrow interstitial ridges. Lepidopleurus produces short, sharp scratches in sets of two, three or four, with wide interstitial ungrazed plateaux.

The faecal pellets of both species contain 5–10 μm sized carbonate particles. Whereas there is little else in Acmaea pellets, which are white, cylindrical and only loosely held together, chiton pellets include much fine manganiferous material, detrital quartz and broken diatom frustules, and are well bound with mucilage which makes them dirty brown-grey in colour and ovoid. The data indicate that physical processes need no longer be assumed to be the major factor in the recycling of carbonate from shells, and in their fragmentation.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1979

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barnes, H. and Klepal, W. 1976. The transmission of radiation through cirripede shells: its relation to the penetration of endolithic algae and photic responses. J. Exp. Mar. Biol. Ecol., 21, 235248.CrossRefGoogle Scholar
Boekschöten, G. J., 1967. Palaeoecology of some Mollusca from the Tielrode Sands (Pliocene, Belgium). Palaeogeogr., Palaeoclimatol., Palaeoecol., 3, 311362.CrossRefGoogle Scholar
Conway, E. and Cole, K. 1977. Studies in the Bangiaceae: structure and reproduction of the conchocelis of Porphyra and Bangia in culture. Phycologia, 16, 205216.CrossRefGoogle Scholar
Deegan, C. E., Kirby, R., Rae, I. and Floyd, R., 1973. The superficial deposits of the Firth of Clyde and its sea lochs. Rep. Inst. Geol. Sci., No. 73/9.Google Scholar
Farrow, G. E., Cucci, M. and Scoffin, T. P., 1978. Calcareous sediments on the nearshore continental shelf of western Scotland. Proc. Roy. Soc. Edinb., 76B, 5575.Google Scholar
Farrow, George, Scoffin, Terence, Brown, Brian and Cucci, Maurice, 1979. An underwater television survey of facies variation on the inner Scottish shelf between Colonsay, Islay and Jura, Inner Hebrides. Scott. J. Geol., 15, 1329.CrossRefGoogle Scholar
Fütterer, D. K., 1974. Significance of the boring sponge Cliona for the origin of fine grained material of carbonate sediments. J. Sedim. Petrol., 44, 7984.Google Scholar
Gobbett, D. J. and Hutchison, C. S. 1973. Geology of the Malay Peninsula {West Malaysia and Singapore). New York: Wiley, 438 pp.Google Scholar
Golubić, S., Perkins, R. D. and Lukas, K. J., 1975. Boring microorganisms and microborings in carbonate substrates. In The Study of Trace Fossils, ed. Frey, R. W., pp. 229259. Berlin: Springer.CrossRefGoogle Scholar
Knight, J. B. et al. , 1960. Treatise on Invertebrate Paleontology. Part 1: Mollusca 1. Geol. Soc. America and Univ. Kansas Press. 351 pp.Google Scholar
Krishnamurthy, V., 1969. The conchocelis phase of 3 species of Porphyra in culture. J. Phycol., 5, 4247.CrossRefGoogle ScholarPubMed
Neumann, A. C. and Land, L. S. 1975. Lime mud deposition and calcareous algae in the bight of Abaco, Bahamas: a budget. J. Sedim. Petrol., 45, 763786.Google Scholar
Schneider, J., 1976. Biological and inorganic factors in the destruction of limestone coasts. Contr. Sedimentology, no. 6. 112 pp.Google Scholar
Stockman, K. W., Ginsburg, P. N. and Shinn, E. A., 1967. The production of lime mud by algae in South Florida. J. Sedim. Petrol., 37, 633648.Google Scholar
Voigt, E., 1977. On grazing traces produced by the radula of fossil and Recent gastropods and chitons. In Trace fossils 2 eds Crimes, T. P. and Harper, J. C., pp. 335346. Geol. J. Sp. Issue No. 9. Seel House Press.Google Scholar
Warme, J. E., 1975. Borings as trace fossils, and the processes of marine bioerosion. The Study of Trace Fossils, ed. Frey, R. W., pp. 181227. Berlin: Springer.CrossRefGoogle Scholar