TEMPORETTI pedro Felix
Iron buffer systemin the water column and partitioning in the sediments of the naturally acidic Lake Caviahue, Neuquén, Argentina
CABRERA, J.M.; DIAZ, M.; SHULTZ, S.; TEMPORETTI, P; PEDROZO, F.
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
ELSEVIER SCIENCE BV
Lugar: Amsterdam; Año: 2017 vol. 318 p. 19 - 26
Sedimentary iron partitioning was studied for five sediment strata (16 cm depth) at three sampling sites of the naturally-occurring acidic Lake Caviahue (Patagonia, Argentina). Additionally, water column iron was modeled based on five-year period input loadings to study a possible iron buffer system. The partition coefficient between thewater column and the total iron content of the sedimentswas also addressed. Sedimentary ironwas found to be distributed, on average, in the following forms: exchangeable (6%), iron oxides (4%), pyrite and reactive organic matter (38%) and residual (non-andesitic) materials with a high content of humic acids (52%). Furthermore,we found that the dissolved iron in the lake was nearly constant throughout the five year period we studied. This is consistent with the existence of an iron buffer system in the lake at pH between 2.0 and 3.0, which may cause differential iron precipitation at the delta of the volcanic river with respect to the deeper northern and southern arms. Sedimentary iron measurements taken at the delta further support the existence of a buffer system, where it was found that the iron content in the sub-superficial stratum (2 cm) was double that of the remainder of the vertical profile at the same site.