Linking shifts in bacterial community with changes in dissolved organic matter pool in a tropical lake

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  • Marcelo P. Ávila, Minas Gerais Federal University
  • ,
  • Luciana P.M. Brandão, Departamento de Biologia Geral, Minas Gerais Federal University
  • ,
  • Ludmila S. Brighenti, Minas Gerais Federal University
  • ,
  • Denise Tonetta
  • Mariana P. Reis, Minas Gerais Federal University
  • ,
  • Peter A. Stæhr
  • Eero Asmala, Helsingin yliopisto
  • ,
  • André M. Amado, Universidade Federal do Rio Grande do Norte
  • ,
  • Francisco A.R. Barbosa, Minas Gerais Federal University
  • ,
  • José F. Bezerra-Neto, Minas Gerais Federal University
  • ,
  • Andréa M.A. Nascimento, Minas Gerais Federal University

Bacterioplankton communities have a pivotal role in the global carbon cycle. Still the interaction between microbial community and dissolved organic matter (DOM) in freshwater ecosystems remains poorly understood. Here, we report results from a 12-day mesocosm study performed in the epilimnion of a tropical lake, in which inorganic nutrients and allochthonous DOM were supplemented under full light and shading. Although the production of autochthonous DOM triggered by nutrient addition was the dominant driver of changes in bacterial community structure, temporal covariations between DOM optical proxies and bacterial community structure revealed a strong influence of community shifts on DOM fate. Community shifts were coupled to a successional stepwise alteration of the DOM pool, with different fractions being selectively consumed by specific taxa. Typical freshwater clades as Limnohabitans and Sporichthyaceae were associated with consumption of low molecular weight carbon, whereas Gammaproteobacteria and Flavobacteria utilized higher molecular weight carbon, indicating differences in DOM preference among clades. Importantly, Verrucomicrobiaceae were important in the turnover of freshly produced autochthonous DOM, ultimately affecting light availability and dissolved organic carbon concentrations. Our findings suggest that taxonomically defined bacterial assemblages play definite roles when influencing DOM fate, either by changing specific fractions of the DOM pool or by regulating light availability and DOC levels.

Original languageEnglish
JournalScience of the Total Environment
Volume672
Pages (from-to)990-1003
Number of pages14
ISSN0048-9697
DOIs
Publication statusPublished - 2019

    Research areas

  • Bacterioplankton, CDOM, Community structure, Mesocosm, Verrucomicrobiaceae

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