Diatom distribution in a temporary pond from the Patagonian Andes (Fantasma Pond) during drought
Villanueva, Verónica Díaz
The distribution of diatoms along a transect from the shore to the centre of an Andean-Patagonian seasonal pond (Fantasma pond, 41°07'S, 71°27'W Argentina) was studied during the dry period. Additionally, during the wet period, communities from different substrates were analysed to evaluate species habitat preference. A total of 48 diatom taxa are reported. Ordination analysis of species from the dried period revealed different assemblages along the shore-centre gradient. The relative abundance of Staurosira pinnata was higher at the centre of the basin, and at the shore, Nitzschia perminuta and Gomphonema spp. dominated the community. Larger species, such as Pinnularia viridis, P. gibba var. gibba and P. acrosphaeria, were more abundant in the site between centre and shore. Low species affinity to any type of habitat (epipelon, epiphyton and phytoplankton) was found. Strictly phytoplanktonic diatom species were not observed. The analysis of species distribution according to species cell-size indicated differences between small and large species in their responses to environmental variables, such as soil water content and organic matter.