The acidic waters of Rio Agrio and Lago Caviahue at Volcan Copahue, Argentina.

GELLER, W.; BAFFICO, G.; DIAZ, M.; FRIESE, K.; KOSCHORRECK, M.; KRINGEL, R.; PEDROZO, F.; SCHIMMELE, M.; WENDT-POTTHOFF, K.; WOELFL, S.

VERH. INTERNAT. VEREIN LIMNOL.

E.Schweizerbart’sche Verlagsbuchhandlung

Lugar: Stuttgart; Año: 2006 vol. 29 p. 1583 - 1586

0368-0770

Many active volcanoes are sources of highly acidic waters that originate from volatile mineral acids. Several crater lakes and volcanic acid brines were chemically characterized (Varekamp et al. 2001), showing a very broad spectrum of dissolved elements, many heavy metals, and high temperatures. For more publications on crater lakes and given constraints in their physical and chemical properties see PASTERNACK & VAREKAMP (1997), Varekamp et al. (2000), and volume 97 (2000) of the Journal of Volcanology and Geothermal Research (”Crater Lakes”, edited by J.C. Varekamp and G.L. Rowe). For volcanoes and their state of activities see Jensen (2000). Copahue Volcano in Argentina has a crater lake near the summit at 2.700 m a.s.l.. Rio Agrio is an acidic river emerging from a geothermic source below the crater lake at the flank of Copahue volcano (DE MOOR et al. 2003). The 13-km-long Upper Rio Agrio flows into a glacial finger-lake, Lake Caviahue (1.600 m a.s.l.), the outflow of which is the Lower Rio Agrio. The system of river stretches and lakes (Fig.1)  shows an acidity gradient from pH 0 to 7 (Pedrozo et al. 2001). The extreme chemistry along this gradient of acidity was studied with an additional focus on microbiology and planktonic and epilithic algae.