Recent environmental changes inferred from sediments in a shallow lake of the Argentinian pampas

PLASTANI, MARÍA SOFÍA; LAPRIDA, CECILIA; MONTES DE OCA, FERNANDA; MASSAFERRO, JULIETA; PANARELLO, HÉCTOR OSVALDO; RAMÓN MERCAU, JOSEFINA; LAMI, ANDREA

JOURNAL OF PALEOLIMNOLOGY

SPRINGER

Lugar: Berlin; Año: 2018

0921-2728

The Pampas are fertile lowland plains that extend across east-central Argentina and are renowned for their agricultural importance. The low geomorphologicrelief of the region accounts for the occurrence of numerous shallow lakes whose sediments constitute paleoenvironmental archives of the outcomes of natural processes and human activities in the Pampas. We identified the main forcing factors behind hydrological shifts during the past ca. 200 years in LaBarrancosa, a shallow lake located in the southeastern Pampas. The data provide a historical context to better understand environmental changes in the area during the twentieth century. Variations in biological (ostracods, chironomids and pigments), geochemical and sedimentological variables were interpreted interms of lake level and trophic state changes. The low diversity of biological assemblages and the autoecology of the ostracod and chironomid taxa suggest thatduring parts of the record assigned to the nineteenth century, near the end of the Little Ice Age, La Barrancosa was a shallow, ephemeral, subsalinewetland, indicating drier-than-present conditions. Thereafter, a hiatus from ca. AD 1860?1940 is attributed to denudation processes during the PampasDust Bowl drought of the 1930s. The onset of wetter