Benthos of a prerennially-astatic, saline, soda lake in Mexico

Abstract

Abstract. The effects of multiple stressors on the benthic macroinvertebrate community were monitored in Tecuitlapa Norte, a shallow, perennially-astatic, warm, mesosaline, sodaalkaline lake in Mexico. Physico-chemical and biological variables were determined monthly for one year. Tecuitlapa Norte displayed a clear seasonal environmental pattern (dry and rainy seasons). The benthic macroinvertebrate community consisted of five species: Culicoides occidentalis sonorensis Jorgensen, Ephydra hians Say, Stratiomys sp., Eristalis sp., and Limnophora sp. of which the first two were dominant and the rest scarce. C. occidentalis was the most important species numerically (76 percent of the total), while E. hians dominated the biomass (73 percent of the total). Primarily salinity and secondarily pH appear to be the most important environmental factors controlling dominance of benthic organisms in Tecuitlapa Norte. Seasonal abundance dynamics of the dominant organisms was associated with phases in their reproductive cycles: environmentally-triggered (i.e., temperature rise, water-level descent) pupation and emergence periods. We concluded that whereas physical and chemical factors (i.e., salinity, pH) exerted the primary control on benthic macroinvertebrate community composition in Tecuitlapa Norte, another assembly of variables (e.g., water-level, temperature) influenced species distribution and abundance.

Alkaliphilism and Carbonate Transport in Alkaliphilic Cyanobacteria (Phormidium sp.) Isolated from Alkaline Lake Lonar, India

“…This is the reason that the two transport systems found in the Phormidium sp isolated from Lonar Lake differ in their pH optima. During the process of desalinization the pH may shift to lower values (Alcocer et al, 1999). Thus during the rainy season as desalinization takes place the TS-I, whose pH optima is lower, becomes the main transport system and during the period of drought the carbonate content in the lake increases which results in the increase in the pH level.…”

The keystone role of anostracans and copepods in European soda pans during the spring migration of waterbirds

“…The terms 'pan' and 'playa' are interchangeable according to Thomas (2011), both referring to shallow, temporary wetlands. Similar soda pans or playa lakes can be found, for example, in Central America and East and South Africa (Hammer, 1986;Alcocer et al, 1999;Verschuren et al, 1999), although information about this habitat type is still scarce (Alcocer et al, 1999).…”