What is the menu today in a subantarctic kelp food web from the Kerguelen Islands? Phytodetritus, phytoplankton and phytobenthos; not living kelp
Type | Article | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Date | 2022-09 | ||||||||||||
Language | English | ||||||||||||
Author(s) | Le Bourg Baptiste1, 2, Saucède Thomas3, Charpentier Anouk1, Lepoint Gilles1, Michel Loïc1, 4 | ||||||||||||
Affiliation(s) | 1 : Laboratory of Oceanology, Freshwater, and Oceanic Sciences Unit of reSearch (FOCUS), University of Liège, Allée du Six Août 13, 4000, Liège, Belgium 2 : Aix-Marseille Université and Université de Toulon, Mediterranean Institute of Oceanography (MIO), CNRS/INSU, IRD, UM 110, Campus universitaire de Luminy, case 901, 13288, Marseille, France 3 : Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 boulevard Gabriel, 21000, Dijon, France 4 : Ifremer, Centre de Bretagne, REM/EEP, Laboratoire Environnement Profond, 29280, Plouzané, France |
||||||||||||
Source | Marine Biology (0025-3162) (Springer Science and Business Media LLC), 2022-09 , Vol. 169 , N. 9 , P. 118 (16p.) | ||||||||||||
DOI | 10.1007/s00227-022-04105-z | ||||||||||||
WOS© Times Cited | 2 | ||||||||||||
Keyword(s) | Benthic communities, Food web, Kelp forests, Mixing models, Stable isotopes | ||||||||||||
Abstract | Kelp forests dominated by Macrocystis pyrifera are widely distributed in coastal waters from boreal, temperate and subantarctic regions. This widespread distribution may result in regional differences in food web structure and functioning. In temperate northern regions, where most studies on kelp forest benthic food webs have been conducted, kelp grazing is a well-documented phenomenon and can lead to the overgrazing of M. pyrifera by sea urchins when their predators (e.g., sea otters) are absent. In contrast, little is known about their counterparts in subantarctic areas. The present study aimed to reconstruct the benthic food web of a kelp forest dominated by M. pyrifera in a subantarctic environment using stable isotope analysis. Stable carbon (δ13C), nitrogen (δ15N) and sulfur (δ34S) isotope ratios were measured from food sources (macrophytobenthos, suspended particulate organic matter SPOM, and sediment) and consumers (sponges, bivalves, gastropods, sedentary and mobile polychaetes, arthropods and echinoderms) which were sampled in a kelp forest of the Kerguelen archipelago. Mixing models highlighted two interconnected trophic pathways which were either supported by SPOM and resuspended macrophytobenthos detritus (bentho-pelagic), or by live micro/macrophytobenthos (phytobenthos-based). No major prey were highlighted for several consumers, indicating the existence of potential supplementary trophic pathways. No consumer relying primarily on living M. pyrifera was highlighted by the mixing models. The investigated kelp forest is hence a complex ecosystem supporting multiple trophic pathways, and direct consumption of M. pyrifera is limited. Nonetheless, M. pyrifera and other macrophytobenthos species may constitute a pool of detritus supporting several trophic pathways. |
||||||||||||
Full Text |
|