Variations in some physico-chemical parameters in a hypersaline coastal lagoon of Baja California, Mexico

Abstract

San Jose lagoon is a hypersaline body of water located in Mexico in the Baja California Peninsula. The lagoon belongs to a system that lies between the fault ridge known as San Jose Creek. Because of its marine origin, it can be considered as thalassohaline, but its isolation from the ocean has brought about changes in its salt composition. It has an area of 13,500 m², a mean depth of 80 cm and a total volume of 10,000 m³. It does not desiccate and can be considered as a permanent lagoon. Seasonal variations are small. TheArtemia population in San Jose produces cysts all year. To determine the physico-chemical conditions inducing permanent production of cysts, temperature, salinity, dissolved oxygen, and pH of the lagoon were monitored, as well as relative humidity and wind conditions in the region in different seasons of the year. From spring to summer, differences of 1 mg L⁻¹ of O₂, 1°C in water temperature, and 8 g L⁻¹ in salinity were observed, and from summer to winter differences of 3.3 mg L⁻¹, 6.5°C, and 14 g L⁻¹, respectively. Despite small seasonal variations, the lagoon exhibits strong spatial and daily changes that are important for cyst production.