What is the menu today in a subantarctic kelp food web from the Kerguelen Islands? Phytodetritus, phytoplankton and phytobenthos; not living kelp

Kelp forests dominated by Macrocystis pyrifera are widely distributed in coastal waters from boreal, temperate and subantarctic regions. This widespread distribution may result regional differences food web structure functioning. In northern regions, where most studies on kelp forest benthic webs have been conducted, grazing is a well-documented phenomenon can lead to the overgrazing of M. sea urchins when their predators (e.g., otters) absent. contrast, little known about counterparts areas. The present study aimed reconstruct environment using stable isotope analysis. Stable carbon (δ13C), nitrogen (δ15N) sulfur (δ34S) ratios were measured sources (macrophytobenthos, suspended particulate organic matter SPOM, sediment) consumers (sponges, bivalves, gastropods, sedentary mobile polychaetes, arthropods echinoderms) which sampled Kerguelen archipelago. Mixing models highlighted two interconnected trophic pathways either supported SPOM resuspended macrophytobenthos detritus (bentho-pelagic), or live micro/macrophytobenthos (phytobenthos-based). No major prey for several consumers, indicating existence potential supplementary pathways. consumer relying primarily living was mixing models. investigated hence complex ecosystem supporting multiple pathways, direct consumption limited. Nonetheless, other species constitute pool