anonymous 16352 Seawater carbonate chemistry and calcification rates of tropical zooxanthellate corals (Stylophora pistillata, Pocillopora damicornis, and Seriatopora hystrix) and cold-water coral (Lophelia pertusa) Cameron, Louise P; Reymond, Claire E; Bijma, Jelle; Büscher, Janina Vanessa; de Beer, Dirk; Guillermic, Maxence; Eagle, Robert A; Gunnell, John; Müller-Lundin, Fiona; Schmidt-Grieb, Gertraud M; Westfield, Isaac T; Westphal, Hildegard; Ries, Justin B (2022): Seawater carbonate chemistry and calcification rates of tropical zooxanthellate corals (Stylophora pistillata, Pocillopora damicornis, and Seriatopora hystrix) and cold-water coral (Lophelia pertusa) [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.952475 Corals are globally important calcifiers that exhibit complex responses to anthropogenic warming and acidification. Although coral calcification is supported by high seawater pH, photosynthesis by the algal symbionts of zooxanthellate corals can be promoted by elevated pCO2. To investigate the mechanisms underlying corals' complex responses to global change, three species of tropical zooxanthellate corals (Stylophora pistillata, Pocillopora damicornis, and Seriatopora hystrix) and one species of asymbiotic cold-water coral (Desmophyllum pertusum, syn. Lophelia pertusa) were cultured under a range of ocean acidification and warming scenarios. Under control temperatures, all tropical species exhibited increased calcification rates in response to increasing pCO2. However, the tropical species' response to increasing pCO2 flattened when they lost symbionts (i.e., bleached) under the high-temperature treatments—suggesting that the loss of symbionts neutralized the benefit of increased pCO2 on calcification rate. Notably, the cold-water species that lacks symbionts exhibited a negative calcification response to increasing pCO2, although this negative response was partially ameliorated under elevated temperature. All four species elevated their calcifying fluid pH relative to seawater pH under all pCO2 treatments, and the magnitude of this offset (Δ[H+]) increased with increasing pCO2. Furthermore, calcifying fluid pH decreased along with symbiont abundance under thermal stress for the one species in which calcifying fluid pH was measured under both temperature treatments. This observation suggests a mechanistic link between photosymbiont loss ('bleaching') and impairment of zooxanthellate corals' ability to elevate calcifying fluid pH in support of calcification under heat stress. This study supports the assertion that thermally induced loss of photosymbionts impairs tropical zooxanthellate corals' ability to cope with CO2-induced ocean acidification. 16360 https://doi.org/10.1594/PANGAEA.952475 2022-12-19T03:06:20+0000 2022 20212 20210 20208 20206 20204 20202 20200 19854 20198 14790 20196 20194 19894 20192 14710 20190 20188 14791 15131 18912 18726 20186 21817 20182 20180 20178 20176 20174 20172 20170 14046 18909 20168 20166 20164