When riverine dissolved organic matter (DOM) meets labile DOM in coastal waters: changes in bacterial community activity and composition
|Author(s)||Blanchet Marine1, Pringault Olivier2, Panagiotopoulos Christos3, Lefevre Dominique3, Charriere Bruno3, 5, Ghiglione Jean-Francois1, Fernandez Camila1, Aparicio Fran L.4, Marrase Celia4, Catala Philippe1, Oriol Louise1, Caparros Jocelyne1, Joux Fabien1|
|Affiliation(s)||1 : UPMC Univ Paris 06, Sorbonne Univ, CNRS, Lab Oceanog Microbienne LOMIC,Observ Oceanol, F-66650 Banyuls Sur Mer, France.
2 : Univ Sci & Tech Languedoc Montpellier 2, Ecol Syst Marins Cotiers ECOSYM UMR5119, CNRS, UM2,UM1, F-34095 Montpellier 5, France.
3 : Univ Sud Toulon Var, Aix Marseille Univ, Mediterranean Inst Oceanog MIO, CNRS INSU IRD UM 110, F-13288 Marseille 09, France.
4 : Inst Ciencies Mar CSIC, Passeig Maritim Barceloneta 37, Barcelona 08003, Spain.
5 : Univ Perpignan, CEFREM, CNRS, UMR 5110, Bat U,Via Domitia UPVD, F-66860 Perpignan, France.
|Source||Aquatic Sciences (1015-1621) (Springer Basel Ag), 2017-01 , Vol. 79 , N. 1 , P. 27-43|
|WOS© Times Cited||27|
|Keyword(s)||Dissolved organic matter, Biodegradation, Coastal waters, Bacterial community composition, Priming effect|
|Abstract||Heterotrophic bacterial communities in marine environments are exposed to a heterogeneous mixture of dissolved organic compounds with different bioreactivity that may control both their activity and composition. The coastal environment is an example of a mixing area where recalcitrant allochthonous organic matter from rivers can encounter labile organic matter from marine phytoplanktonic blooms. The objective of this study was to explore the effects of mixed qualities of dissolved organic matter (DOM) on bacterial community activity (BCA) and bacterial community composition (BCC) and to test for a priming effect when DOM sources are added in combination. Coastal marine bacterial communities were incubated separately with a mixture of amino acids and with natural riverine DOM or with both sources together for 42 days. Addition of amino acids alone or in combination with riverine DOM led to a similar stimulation of BCA compared to control condition, whereas addition of riverine DOM alone did not modify BCA compared to the control. On the contrary, BCC analyzed by 16S rRNA gene pyrosequencing was not affected by the addition of amino acids alone, but changed dramatically with riverine DOM alone or in combination with amino acids. Our results show that changes in BCA and BCC can be driven by different types of DOM, but that these changes are not necessarily coupled. Moreover, the addition of labile DOM did not modify the microbial decomposition of riverine DOM, nor the BCC, suggesting that a priming effect did not occur under these experimental conditions.|