Ecophysiology of Kuwaiti macroalgae with special emphasis on temperature and salinity tolerance related to the conditions at desalination plant outfalls

Abstract Brine discharged from seawater desalination plants impacts marine life by exposure to increased salinity and, in some cases, temperature. However, the responses of individual species to such stress remains poorly known yet their understanding is essential for assessing and predicting the impacts of seawater desalination plants. In this study, unialgal cultures obtained by the germling emergence method of 34 taxa representative of the Rhodophyta, Chlorophyta and Phaeophyceae seaweeds in the Arabian Gulf, and isolated from the vicinity of two large desalination plants in Kuwait, were subjected to increased temperature and salinity under experimental conditions in the laboratory. The dataset is complemented by measurements of seawater temperature and salinity obtained at increasing distances from the outfalls of desalination plants and along the Kuwaiti coastline including from two pristine areas, Boubiyan and Fintas. Chlorophyta, especially Ulva spp., and Phaeophyceae displayed remarkable tolerance against hypersaline and thermal stress, suggesting that this group can cope better with adverse environmental conditions. Members of the Rhodophyta were considerably more sensitive to temperature increases.