MEPS 260:151-159 (2003)  -  doi:10.3354/meps260151

ABSTRACT: Spatial and temporal diversity of food sources of intertidal nematodes of 3 different feeding habitats (estuarine muddy sediments, Spartina maritima and Juncus maritimus marshes) in the Roscoff Aber Bay, France, was assessed by the use of δ¹³C and δ¹⁵N values. Within the bay, nematodes largely dominated within the total meiofauna. Throughout the 3 sampling periods, the δ¹³C and δ¹⁵N values for nematodes and sources showed that the dominant sedimentary organic matter sources within the 3 microhabitats considered, namely terrigeneous inputs, detrital Spartina maritima or Juncus maritimus and marine POM, did not contribute a significant part of the diet to locally occurring nematodes. In fact, the δ¹³C and δ¹⁵N values indicate that organic matter derived from stranded macroalgae, mostly Enteromorpha sp. and Fucus spiralis, was the primary contributor to the assimilated food sources of nematodes; more readily utilisable sources (i.e. benthic diatoms) are virtually absent. The present work provides evidence that detrital pathways, including stranded macroalgae from nearby rocks and free-living nematodes, play a key role in the trophic ecology of intertidal flat areas.

KEY WORDS: Nematodes · Feeding ecology · Intertidal bay · Stranded algae · Stable isotopes