BIOGENIC SILICA IN THE WETLANDS ON THEIR RELATIONSHIP WITH SOIL AND GROUNDWATER BIOGEOCHEMISTRY IN THE SOUTHEARSTERM

BERNAVA GUSTAVO VICENTE; NATALIA BORRELI; M F ALVAREZ ; OSTERRIETH MARGARITA

ELSEVIER SCIENCE B. V.

MANAGER

Año: 2012

Springer-Verlag 2011Abstract Although phytoliths constitute part of the wet-land suspended load, there are few studies focused on thequantification of them in the biogenic silica (BSi) pool. So,the aim of this paper is both to determine BSi content(diatoms and phytoliths) and its relationship with dissolvedsilica in surface waters, and the influence of soil andgroundwater Si biogeochemistry in Los Padres wetland(Buenos Aires Province, Argentina). In the basin of theLos Padres wetland, dissolved silica (DSi) concentration isnear 840 ± 232 lmol/L and 211.83 ± 275.92 lmol/L ingroundwaters and surface waters, respectively. BSi repre-sents an 5.6–22.1% of the total suspension material, and8–34% of the total mineralogical components of the wet-land bottom sediments. DSi and BSi vary seasonally, withhighest BSi content (diatoms specifically) during thespring–summer in correlation to the lowest DSi concen-tration. DSi (660–917.5 lmol/L) and phytolith (3.35–5.84%) concentrations in the inflow stream are higher thanin the wetland and its outflow stream (19.1–113 lmol/L;0.45–3.2%, respectively), probably due to the high phyto-lith content in soils, the high silica concentration in the soilsolution, and the groundwater inflow. Diatom content(5–16.8%) in the wetland and its outflow stream is higherthan in the inflow stream (0.45–1.97%), controlling DSi inthis system. The understanding of the groundwater–surfacewater interaction in an area is a significant element fordetermining the different components and the role that theyplay on the local biogeochemical cycle of Si.Keywords Biomineralization - Diatom - PhytolithEN ESTE ARTICULO SE ME AGRADECE LA COLABORACION