Parochlus steinenii (Diptera: Chironomidae) as a bioindicator model of water quality in Antarctic freshwater ecosystems

Dr Enrique Morelli, Facultad de Ciencias

Faunal studies provide information on the functioning, structure, and natural variability of ecosystems, being a fundamental requirement for the establishment of monitoring programs. They are a basic tool for the conservation of biodiversity and anthropogenic impact assessment. The diversity of insects in Antarctica is restricted to two species of chironomid dipterans, Belgica antarctica Jacobs, 1900 (which has not yet been recorded for the area of influence of the Artigas Antarctic Scientific Base) and Parochlus steinenii Gerke, 1889 with a limited distribution to the South Shetland Islands. Of all organisms found within an aquatic ecosystem, insects offer advantages to be used as indicators of contamination since they are found in almost all habitats, are abundant, easy to collect and extremely sensitive to disturbances. Within aquatic insects, the Chironomidae family is one of the most abundant and diverse. Parochlus steinenii is a study model of several Antarctic research teams in the different Stations, either as an indicator of climate change or in studies of genetic interest. This research team evaluated the possible use of P. steinenii as a bioindicator model of water quality.

The first survey of Diptera fauna for the Uruguayan Basin was carried out in February 2015. A survey is currently being carried out on Lake Uruguay (Artigas Antarctic Scientific Base), Lake Kitiesh (Bellingshausen Base and President Eduardo Frei) and Great Wall Lake (Great Wall Base). Sampling is carried out using pitfall traps located in two transects parallel to the lakes edge with four traps each, with a one-meter interconnect between transects and at a distance of 2 meters each trap. The adults collected are preserved in 70% alcohol for later conditioning in the laboratory. Abundance is determined, physicochemical factors are analyzed and these are related among them in order to evaluate the state of the fresh water bodies used as a source of drinking water supply based on the presence of P. steinenii as a bioindicator model and to be able to establish a bioindex of water quality.