Modern diatom assemblages in surface sediments from shallow lakes and streams in southern Pampas (Argentina)

HASSAN, GABRIELA S.; TIETZE, ELEONOR; DE FRANCESCO, CLAUDIO G.

Aquatic Sciences

Birkhäuser Verlag

Lugar: Basel; Año: 2009 vol. 71 p. 487 - 499

1015-1621

Diatom assemblages preserved in continental sedimentary successions of the southern Pampas (Argentina) can provide useful indicators of past environmental changes. Ecological data, however, are scarce. In order to provide modern data for diatom-based paleoenvironmental reconstructions, sediments from shallow lakes and streams of the region were analyzed. A total of 131 diatom species were identified. Canonical  correspondence analysis was used to identify the physical and chemical environmental parameters that best explained the distribution of taxa. Cocconeis placentula, Hippodonta hungarica, Navicula  veneta, Cyclotella meneghiniana and Nitzschia amphibia occoneis placentula, Hippodonta hungarica, Navicula  veneta, Cyclotella meneghiniana and Nitzschia amphibia , Cyclotella meneghiniana and Nitzschia amphibia  were the most widely extended species. The highest percentage variance in diatom data was explained by conductivity and nutrient concentrations. Diatom assemblage composition was more variable in shallow  lakes than in streams, which is in agreement with the different hydrological and geomorphological characteristics of these environments. The results obtained in the present work provide useful analogues for paleoenvironmental reconstructions of water bodies in southern Pampas. occoneis placentula, Hippodonta hungarica, Navicula  veneta, Cyclotella meneghiniana and Nitzschia amphibia , Cyclotella meneghiniana and Nitzschia amphibia  were the most widely extended species. The highest percentage variance in diatom data was explained by conductivity and nutrient concentrations. Diatom assemblage composition was more variable in shallow  lakes than in streams, which is in agreement with the different hydrological and geomorphological characteristics of these environments. The results obtained in the present work provide useful analogues for paleoenvironmental reconstructions of water bodies in southern Pampas.