Bacterioplankton structure from shallow lakes located at the upper and lower Salado River Basin (Argentina) influenced by different land uses

SCHIAFFINO M.R.; LAGOMARSINO L.; TORREMORELL A.; SEOANE ROCHA C.; LLAMES M.E.; CASTRO-BERMAN M.; FERMANI P.; HUBER M.P.

Honolulu

Congreso; ASLO Aquatic Sciences Meeting - Mountains to the sea; 2017

American Society of Limnology and Oceanography

The Salado River basin is one of the largest and most important of Argentina and comprises one of the main toad producing areas. The Salado river runs along 700 km northwest-northeast across the Pampa Region. The upper basin is characterized by agricultural land uses (corn-soybeans-wheat rotations) in its surroundings, whereas the lower basin is influenced predominantly by livestock activities. We studied 4 Pampean shallow lakes located in the upper and lower Salado River 8asin in order to compare their core bacterioplankton biosphere. We found that shallow lakes located in the upper basin showed higher values of TP (790 ppb) and mainly as dissolved form (60% from the TP) than those of the lower basin (420 ppb and 40%). About 56% of the OTUs were shared between shallow lakes from upper and lower basins, whereas 15% were exclusive of upper basin and 29% of the lower basin shallow lakes. The upper basin showed an average of 19±6 OTUs per lake, whereas the lower basin an average of 27±5. The non-metric MDS based on the dominant bacterioplankton composition showed that shallow lakes from the upper basin ordered separately from those of the lower basin, being significantly different (ANOSIM R=0.72;p=0.0001). Similarity percentage analysis indicated an overall dissimilarity of bacterioplankton composition among basins of 77%. Redundancy analyses showed that environmental variables explained 45% of the variance and those lakes from the upper basin ordinated together with higher values of conductivity and TP, and separately from the shallow lakes of the lower basin, suggesting the influence of land uses on bacterioplankton composition.