Microbial abundance patterns along a transparency gradient in Pampean shallow lakes

FERMANI P.; TORREMORELL A.; LAGOMARSINO L.; ESCARAY, R.; UNREIN F.; PÉREZ, G.

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2015 vol. 752 p. 103 - 123

0018-8158

We  studied  the  components  of  the  microbial food  web and  the  degree  of  coupling between heterotrophic flagellates (HF) and heterotrophic bacteria (HB) in a set of 40 shallow lakes of the Pampa Plain over a wide range of water transparency and nutrient levels. Our results showed that abundances of most components of microbial trophic web were very high. HB abundances ranged from 1.4x106 to 4.2x108 cells ml-1. Also HF and ciliates showed a wide range  of  abundances,  with  values  from 150 to  3.9x105 HF ml-1,and from  undetectable  values  to  910 ciliates  ml-1 respectively. We  founded  significant  relationships  between HB and  water  transparency,  chlorophyll-a and total phosphorus  concentrations;  while HF and  cliliates did  not  exhibit  significant  changes  with  increments  in  trophic status.  We  found several lakes  with  high HB  and  low  HF  abundances, which  suggest  that  these  components  often are not couple. Also, we found that the microbial community composition in lakes of the Pampa plain could not be segregated into two discrete groups according to current theories of shallow lakes, being distributed as a continuum.