A review of oxygen supersaturation in Sivash Bay and globally in hypersaline waters: examining its origin and environmental effects

Context Review of oxygen supersaturation events in hypersaline waters, mechanisms contributing to their origin, and their influence on the ecosystems. Aims To understand how often oxygen supersaturation states occur in hypersaline waters, what mechanisms contribute to their origin, and how they influence the ecosystems. Methods Collection and examination of data on oxygen supersaturation events in Sivash Bay, the world’s largest hypersaline lagoon, as well as in hypersaline lakes and lagoons globally. Key results The summer oxygen supersaturation in water is a common characteristic of highly productive hypersaline water bodies, not just in Crimea but also in various regions of Europe, Asia, Australia, and America. The oxygen saturation of water, even at night, can reach up to 500% for several sunny days. This phenomenon is particularly noticeable in floating mats of filamentous green algae, where the oxygen saturation is higher and lasts longer. Conclusions This study shows that the largely neglected environmental hyperoxia is a common phenomenon and can have various effects on organisms and their populations, similar to other factors, which may be classified as threats or benefits. Implications These data are crucial for the environmental management of hypersaline water bodies, their exploitation, and the promotion of sustainable aquaculture in these environments.