V. Creach et al., STABLE ISOTOPES AND GUT ANALYSES TO DETERMINE FEEDING RELATIONSHIPS IN SALT-MARSH MACROCONSUMERS, Estuarine, coastal and shelf science, 44(5), 1997, pp. 599-611
While some saltmarsh Vegetation is exported by tides to coastal waters
, most saltmarsh vegetation remains and decomposes on site. After micr
obial action, this plant material can be assimilated by macro-inverteb
rates. Diets of the amphipods Orchestia gammarellus and Corophium volu
tator, the polychaete Hediste diversicalor and the pulmonate Ovatella
bidentata were analysed using isotopic analysis, together with direct
description of gut contents for 0. gammarellus. Analysis of carbon and
nitrogen isotopic compositions, as well as of gut analyses, showed th
at the diet of 0. gammarellus consisted of more than 50% plant detritu
s, although its origin was difficult to identify in gut contents. For
other species studied, benthic diatoms were the most important food so
urce, sometimes exclusively so for 0. bidentata and C. volutator, and
were otherwise sometimes associated with plant detritus for H. diversi
color. In this study, isotopic analyses provided a good indication of
macro-invertebrate diets. The results confirm those of other studies w
hich indicate that these four invertebrates are deposit feeders. (C) 1
997 Academic Press Limited.