Some abiotic characteristics of shallow ponds included in an Andean peatland of the transitional desert of Chile

Abstract

The study ponds are part of a peatland located in the Elqui river basin of the Andes. They turned out to be heliotropic (homoeothermic), mesotrophic and mesopoikilohaline microlimnotopes. The ponds showed high content of dissolved metals, mainly Ca (mean ~205 mg/l), Na (~60 mg/l), Mg (~60 mg/l) and K (~13 mg/l), and the inorganic non-metals sulfate (~976 mg/l), chloride (~34.2 mg/l), phosphate (~23 mg/l), bicarbonate (~11 mg/l) and nitrate (~3.3 mg/l). Excluding Hg, Se and nitrite, trace elements were represented by Al, As, Cd, CN, Cu, Cr, Fe, Ba, Be, Co, Zn, Mo, Ni, Pb, Li, Ag, and V. The cationic pattern of ponds was Ca > Na > Mg > K >Mn; whereas the anionic pattern was sulfate > chloride > phosphate > carbonate > Fl. Although we did not study, the hydrochemical characteristics of these water bodies seem to reflect the characteristics of the geological substrate of the mountains through which the water drains into the peatland.