Controlling factors in planktonic communities over a salinity gradient in high altitude lakes

DIEGO FRAU; YAMILA BATTAUZ; GISELA MAYORA; PATRICIA MARCONI

ANNALES DE LIMNOLOGIE-INTERNATIONAL JOURNAL OF LIMNOLOGY

EDP SCIENCES S A

Lugar: Paris; Año: 2015 vol. 52 p. 261 - 272

0003-4088

This study aimed to determine the factors affecting plankton structure along a salinity gradientduring the summer in high-altitude endorheic lakes in Catamarca Province (Argentina). During the summer2013, eight lakes located between 3000 and 4300 meters above sea level were sampled in a 6-day period beinganalysed plankton, limnological variables and flamingo abundance. Principal Component Analysis explained80% of the system variability, permitting lakes to be ordered by salinity: subhaline (SH), hypohaline (HH)and mesohaline (MH). A total of 101 phytoplankton taxa were registered, having Bacillariophyceae thehighest richness (43 species registered). HH lakes were dominated by Bacillariophyceae (between 65 and100%), while Chlorophyceae and Euglenophyceae were more abundant in SH and MH lakes. Zooplanktonwas poorly represented in richness (only 21 species were registered). MH lakes were dominated by Copepoda(>85% of total abundance) and HH lakes by Rotifera (>51% of total abundance). It was not found aclear pattern in SH lakes. The redundancy analysis explained 70.7% of phytoplankton variability and 75.7%of zooplankton variability. Bacillariophyceae presence was associated with availability of dissolved silica(Si), while Euglenophyceae and Chlorophyceae were associated with a higher nitrogen:phosphorus ratio.Cladocera and Copepoda abundance were linked to Euglenophyceae abundance and the area of lakes whileRotifera displayed a positive relation with the concentration of dissolved organic matter. We conclude thatboth phytoplankton and zooplankton abundance are mainly controlled by Bottom-Up forces includingdissolved Si for Bacillariophyceae, and availability of Euglenophyceae for zooplankton while salinity andaltitude have an effect on plankton richness distribution.