BALTOMS

Biotic and Abiotic Lability of Terrestrial Organic Matter in Seawater

MIO Participants : J-F Rontani, P. Bonin, S. Guasco, F. Vaultier et A. Portas

Partenaire: CEREGE (O. Radakovitch)

The BALTOMS project (2017-2019) is funded by Labex OT-MED.

It focuses on the study of the biotic degradation of terrestrial OM (MOPT) discharged by rivers into the sea. Indeed, until recent years this MOPT was considered refractory to degradation, whereas it undergoes intense biotic and abiotic degradation in estuaries.

Main results obtained

MOPT degradation favored at high salinity (change in bacterial community structure → selection of bacteria that degrade MOPT more efficiently).
MOPT degradation accelerated in the presence of potamoplankton (priming effect) (assimilation of recalcitrant substrates (MOPT) favored in the presence of easily assimilable co-substrates (freshwater diatoms)).
In situ confirmation (evidence of a priming effect induced by marine diatoms).
DNA/RNA isotope tagging of communities adapted to marine MOPT/MO degradation is currently underway (DNA - SIP) to identify the bacteria involved in MOPT degradation.

Publications

Master 2 internship report by M-H. PRIME (2017)
Bonin P., Prime A-H., Galeron M-A., Guasco S. et Rontani J-F. (2019) Enhancement of biotic degradation of terrestrial particulate organic matter in an estuarine salinity gradient: Interactive effects of organic matter pools and changes of bacterial communities. Aquatic Microbial Ecology 83: 147-159.