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Long-term exposure to increasing temperatures on scleractinian coral fragments reveals oxidative stress

Dias, Marta, Ferreira, Ana, Gouveia, Raúl, Madeira, Carolina, Jogee, Nadia, Cabral, Henrique, Diniz, Mário, Vinagre, Catarina
Marine environmental research 2019 v.150 pp. 104758
Scleractinia, catalase, chronic exposure, coral bleaching, corals, enzyme activity, global warming, glutathione transferase, heat stress, lipid peroxidation, mortality, oxidative stress, storms, temperature
Global warming is leading to increases in tropical storms' frequency and intensity, allowing fragmentation of reef-forming coral species, but also to coral bleaching and mortality. The first level of organism's response to an environmental perturbation occurs at the cellular level. This study investigated the long-term oxidative stress on fragments of nine Indo-Pacific reef-forming coral species exposed for 60 days to increasing temperatures (30 °C and 32 °C) and compared results with control temperature (26 °C). Coral overall condition (appearance), lipid peroxidation (LPO), catalase activity (CAT), and glutathione S-transferase (GST) were assessed. The species Turbinaria reniformis, Galaxea fascicularis, and Psammocora contigua were the most resistant to heat stress, presenting no oxidative damage at 30 °C. Unlike G. fasciularis, both T. reniformis and P. contigua showed no evidence of oxidative damage at 32 °C. All remaining species' fragments died at 32 °C. Stylophora pistillata and Pocillopora damicornis were the most susceptible species to heat stress, not resisting at 30 °C.