Organic matter ingestion and assimilation rates by the sea cucumber Holothuria (Holothuria) tubulosa (Gmelin, 1788) at different temperatures and potential effects on benthic trophic status.

We investigated the effects of different temperature anomalies (up to +12 °C) on the biochemical features of sediments offered to specimens of the sea cucumber Holothuria (Holothuria) tubulosa (Gmelin, 1788) and of its feces. We also estimated ingestion and assimilation rates of different classes of organic compounds after the different treatments. The exposure to temperature anomalies influenced the metabolism and organic matter assimilation efficiency of H. tubulosa. Counterintuitively, our results would suggest that H. tubulosa , irrespectively of temperature, might not be the best option for removing excess organic matter from eutrophicated sediments, though having consequences on the organic matter nutritional quality. Since oceans' temperature is projected to further increase by 2100 along with frequency, intensity and duration of marine heatwaves, H. tubulosa will most likely experience a potential contraction of its distribution areal, with cascading consequences on benthic trophic webs dynamics. • Detritivore sea cucumbers are strong benthic bioturbators • Temperature influences sea cucumbers feeding behavior and feces composition • Heat waves affect sea cucumbers metabolism and, thus, benthic trophic status • Temperature exceeding 30 °C represent the highest limit of their thermal tolerance • Future changes in sea cucumbers distribution might alter sedimentary biogeochemistry [ABSTRACT FROM AUTHOR]