The Fauna of Sand and Mud Banks Near the Mouth of the Exe Estuary

Holme, N. A.

doi:10.1017/s0025315400055284

Cited by 80 publications

(41 citation statements)

References 35 publications

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“…All the major species are well-known representatives of the Macoma community, except for Ampharete which is not usually associated with this assemblage elsewhere and appears to be peculiar to south-west England. It is common in regions of higher salinity in the Tamar (Spooner & Moore, 1940) and Exe (Holme, 1949). The dominance of the errant polychaete Nephtys hombergi rather than Nereis diversicolor is typical of the Macoma community at the higher end of its salinity range.…”

Section: Species Compositionmentioning

confidence: 99%

Macrofauna production in an estuarine mud-flat

1975

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(Text-figs. 1-6)The macrofauna of an intertidal Macoma community has been studied by monthly sampling over the period October 1972 to October 1973. Production estimates have been made for the six major species present by computing mortality and residual biomass. The major producer was Nephtys hombergi. Three year-classes of this species were present. The biomass, averaged over the year, was 3-947 g/m 2 and the production 7-335 g/m 2 /year, giving a P:B ratio of 1-9:1. Ampharete acutifrons is an annual species with a mean biomass of 0-426 g/m 2 and a production of 2-322 g/m 2 /year (P:B ratio 5-5:1). The most productive bivalve was Mya arenaria, with a mean biomass of 5-537 g/m 2 and a production of 2-659 g/m 2 /year (P:B ratio 0-5:1). This species has invaded southwest England within the last ten years and the population has not reached a stable state. The other bivalves are Scrobicularia plana (mean biomass 2-146 g/m 2 , production 0-482 g/m 2 /year, P:B ratio 0-2:1), Macoma balthica (mean biomass 0-337 g/m 2 , production 0-308 g/m 2 /year, P:B ratio 0-9:1) and Cerastoderma edule (mean biomass 0-847 g/ m2 > production 0-205 g/m 2 /year, P:B ratio 0-2:1).The total production was 13-311 g/m 2 /year, which coincidentally almost exactly equalled the total mean biomass of 13-240 g/m 2 . Comparison with other areas shows that this production figure is about average for benthic communities. However, it is thought that the meiofauna production must be high in this situation because the top macrofauna producer, Nephtys hombergi, is a carnivore. I N T R O D U C T I O NThe importance of the extensive intertidal mud-flats to the energy budget of estuaries has frequently been stressed, but seldom quantified. Smidt (1951) has discussed the production of both macro-and meiofauna from the Danish Waddens in general terms but, because of the wide coverage, his information is not detailed enough to quantify annual production in terms of g/m 2 . The present study was designed to compare the productive importance of macrofauna and meiofauna in detail at a single site. This paper deals only with the first phase of this study, the macrofauna, which are retained on a 0-5 mm sieve for the major part of their productive life.Population studies on several species typical of intertidal mud-flats have been undertaken previously by various authors, but production of the total macrofauna assemblage of a given area has not been estimated. It should be stressed that the present estimate is applicable only to the site studied and to the year of the study, but serves to illustrate the order of magnitude to be expected and, following later work on the meiofauna, will illustrate the relative importance of the two size-components of the fauna. The data obtained provide production estimates, and no effort has been made to derive complete life-histories. For example, the exact spawning period is often not known, except where disappearance of gametes has been observed incidentally or where inferences can be drawn from the appearance of 'O' group settl...

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Section: Species Compositionmentioning

confidence: 99%

Macrofauna production in an estuarine mud-flat

1975

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“…A descriptive account of the estuary has been given by Holme (1949), to which little can be added. Four transects along the eastern shore were selected for quantitative sampling, two across the muddy shores at Topsham (To) and Lympstone (Ly), and two across the sands at Shelly Bank (Sh) and Orcombe Point (Op) level could not be sampled.…”

Section: Description Of Study Areamentioning

confidence: 99%

Nematode associations in the Exe estuary

Warwick¹

1971

J. Mar. Biol. Ass.

106

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INTRODUCTIONThe problems involved in the identification of freeliving marine nematodes have stood in the way of ecologists for some time. Although considerable advances are now being made on the continent (particularly in Kiel Bay and the Mediterranean) and in North America, our lack of knowledge of the British species is still lamentable. In order to rectify this state of affairs to some extent, a study of the distribution of nematodes in the Exe estuary was planned to cover as wide a spectrum of physical and chemical conditions as possible, ranging from fine muds with a low interstitial salinity at the head of the estuary to coarse sands with a high salinity at the mouth. It is hoped that the characterization of the fauna of various habitats in the estuary will form a basis for further ecological studies in other areas. Not surprisingly, a large proportion of the species found were new British records, and some new to science. The fourteen species of this latter group discussed in this paper are described elsewhere (Warwick, 1970).

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“…Synthesizing existing data on communities from the North Sea, Jones (1950) placed "communities" and "zones" into specific sediment types, noting that differences in the supply of detritus and organism mobility might contribute to observed patterns. Still, when Thorson (1957) synthesized the available data on infaunal distributions, developing the concept of "parallel levelbottom communities", very few studies actually included quantitative information on the sediments (e.g., grain-size distributions) in which the organisms were collected (some exceptions include, for example, Ford, 1923;Sparck, 1933;Stephen, 1933;Thorson & Ussing, 1934;Holme, 1949). In fact, it was the dual effect of Thorson's (1957) generalisations and Sanders ' (1958) observation that different infaunal feeding types tended to dominate sandy versus muddy sediments that prompted the plethora of -subsequent studies of the relationship between distributions of infauna and sediments (e.g., Table 1).…”

Section: Infauna and Sediments Historical Perspectivementioning

confidence: 99%

The importance of fine-scale flow processes and food availability in the maintenance of soft-sediment communities

Snelgrove¹

1993

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The Fauna of Sand and Mud Banks Near the Mouth of the Exe Estuary

Cited by 80 publications

References 35 publications

Macrofauna production in an estuarine mud-flat

Macrofauna production in an estuarine mud-flat

Nematode associations in the Exe estuary

The importance of fine-scale flow processes and food availability in the maintenance of soft-sediment communities

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