@article {5916, title = {Variation of the isotopic composition of dissolved organic carbon during the runoff cycle in the Amazon River and the floodplains}, journal = {Comptes Rendus Geoscience}, volume = {350}, year = {2018}, pages = {65{\textendash}75}, doi = {10.1016/j.crte.2017.11.001}, url = {https://doi.org/10.1016/j.crte.2017.11.001}, author = {Patrick Alb{\'e}ric and Marcela A.P. P{\'e}rez and Patricia Moreira-Turcq and Marc F Benedetti and Steven Bouillon and Gwena{\"e}l Abril} } @article {4340, title = {The fate of C4 and C3 macrophyte carbon in central Amazon floodplain waters: Insights from a batch experiment}, journal = {Limnologica - Ecology and Management of Inland Waters}, volume = {59}, year = {2016}, pages = {90-98}, abstract = {

The central Amazon floodplains are particularly productive ecosystems, where a large diversity of organic carbon sources are available for aquatic organisms. Despite the fact that C4 macrophytes generally produce larger biomasses than C3 macrophytes, food webs in the central Amazon floodplains appear dominantly based on a C3 carbon source.

In order to investigate the respective fate and degradation patterns of C4 and C3 aquatic plant-derived material in central Amazon floodplains, we developed a 23-days batch experiment. Fatty acid and carbon concentrations as well as stable isotope compositions were monitored over time in 60\ L tanks. These tanks contained Amazon water, with different biomasses of C3 and C4 macrophyte, representative of in situ densities occurring in central Amazon floodplains.

In the C4Paspalum repens treatments, organic (POC, DOC) and inorganic carbon (DIC) got rapidly enriched in 13C, whereas in the C3Salvinia auriculata treatments, POC and DOC showed little change in concentration and isotopic composition, and DIC got depleted in 13C. The contribution of P. repens to POC and DOC was estimated to reach up to 94.2 and 70.7\%, respectively. In contrast, no differences were reported between the C3S. auriculata and control treatments, an observation attributed to the lower C3 biomass encountered in the field, to a slower degradation rate of C3 compared to C4 compounds, and to similar isotopic compositions for river POC and DOC, and C3 compounds.

The 13C enrichments of POC, DOC, and DIC from P. repens treatments were attributed to an enhanced bacterially-mediated hydrolysis and mineralization of C4 material. Evolutions of bacterial abundance and branched fatty acid concentrations confirmed the role of heterotrophic microbial communities in the high P. repens decomposition rate. Our experiment highlights the predominant role of C4 aquatic plants, as a large source of almost entirely biodegradable organic matter available for heterotrophic activity and CO2 outgassing to the atmosphere.

}, keywords = {Central amazon, Degradation, fatty acids, Floodplains, Macrophytes, Stables isotopes}, doi = {doi:10.1016/j.limno.2016.03.008}, author = {Jean-Michel Mortillaro and Passarelli, C and Gwena{\"e}l Abril and C{\'e}dric Hubas and Luis Felipe Artigas and Marc F Benedetti and Najet Thiney and Moreira-Turcq, P and P{\'e}rez, M A and Vidal, L and Tarik Meziane} } @article {Abril2014, title = {{Amazon River carbon dioxide outgassing fuelled by wetlands}}, journal = {Nature}, volume = {505}, year = {2014}, pages = {395-398}, publisher = {Nature}, doi = {10.1038/nature12797}, author = {Gwena{\"e}l Abril and Martinez, Jean Michel and Luis Felipe Artigas and Moreira-Turcq, Patricia and Marc F Benedetti and Vidal, Luciana and Tarik Meziane and Kim, Jung-Hyun and Bernardes, Marcelo C and Savoye, Nicolas and Deborde, Jonathan and Lima Souza, Edivaldo and Alb{\'e}ric, Patrick and Fernandes, Marcelo and de Souza, Landim and Roland, Fabio} }