Bell J. J. auteur aut IRD Shaffer M. auteur aut IRD Luter H. M. auteur aut IRD Mana R. auteur aut IRD Rodolfo-Metalpa Riccardo auteur aut IRD text journalArticle eng text/pdf born digital access Sponges are major components of benthic communities across the world and have been identified as potential "winners" on coral reefs in the face of global climate change as result of their tolerance to ocean warming and acidification (OA). Previous studies have also hypothesised that photosymbiont-containing sponges might have higher productivity under future OA conditions as a result of photosymbionts having increased access to CO2 and subsequently greater carbon production. Here we test this hypothesis for a widespread and abundant photosymbiont-containing sponge species Lamellodysidea herbacea at a CO2 seep in Papua New Guinea simulating OA conditions. We found seep sponges had relatively higher cyanobacterial abundance, chlorophyll concentrations and symbiont photosynthetic efficiency than non-seep sponges, and a three-fold higher sponge abundance at the seep site. However, while gross oxygen production was the same for seep and non-seep sponges, seep sponge dark respiration rates were higher and instantaneous photosynthesis: respiration (P:R) ratios were lower. We show that while photosymbiont containing sponges may not have increased productivity under OA, they are able to show flexibility in their relationships with microbes and offset increased metabolic costs associated with climate change associated stress. specialized CO2 seep ocean acidification Papua New Guinea Porifera respiration PAPOUASIE NOUVELLE GUINEE 034 032 28 16 4900-4911 2022 1354-1013 https://www.documentation.ird.fr/hor/fdi:010085224 10.1111/gcb.16235 1354-1013 [F B010085224] https://www.documentation.ird.fr/hor/fdi:010085224 https://www.documentation.ird.fr/intranet/publi/2022-07/010085224.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2022-07-01 2024-09-02 fdi:010085224 fre