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Food web structure within kelp holdfasts ( Laminaria ): a stable isotope study
Author(s) -
Schaal Gauthier,
Riera Pascal,
Leroux Cédric
Publication year - 2012
Publication title -
marine ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 58
eISSN - 1439-0485
pISSN - 0173-9565
DOI - 10.1111/j.1439-0485.2011.00487.x
Subject(s) - kelp , food web , kelp forest , ecology , trophic level , ecosystem engineer , ecosystem , laminaria digitata , isotope analysis , fauna , primary producers , detritivore , biology , phytoplankton , nutrient
Kelp holdfasts are highly reticulated structures which host a large diversity of small fauna. These microhabitats have been reported to play a crucial role in the biodiversity associated to kelp forest ecosystems. This study aimed at identifying trophic links and the main food sources sustaining food webs within communities associated with kelp holdfasts, through a stable isotope (δ 13 C and δ 15 N) approach. Sampling of the main invertebrates inhabiting Laminaria digitata holdfasts, and of their potential food sources, took place in February and May 2007. Stable isotope results reveal that most of the primary consumers, including filter‐feeders and deposit‐feeders, rely on the particulate organic matter sedimented within kelp holdfasts. Only three grazers departed from this general pattern. The correspondence between the stable isotope ratios of predators and sediment consumers indicated that this source is at the base of the main pathway through which energy and matter transit in the food web. δ 15 N ranges found for consumers revealed that the food web associated with kelp holdfasts is composed of 3.5 levels. In spite of the low diversity of food sources at the base of the food web, these microhabitats can therefore be considered micro‐scale ecosystems, from a functional perspective.