@article {8409, title = {Carbon dynamics driven by seawater recirculation and groundwater discharge along a forest-dune-beach continuum of a high-energy meso-macro-tidal sandy coast}, journal = {Geochimica et Cosmochimica Acta}, volume = {317}, year = {2022}, month = {Jan-01-2022}, pages = {18 - 38}, issn = {00167037}, doi = {10.1016/j.gca.2021.10.021}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0016703721006244}, author = {Charbonnier, C{\'e}line and Anschutz, Pierre and Gwena{\"e}l Abril and Mucci, Alfonso and Deirmendjian, Loris and Poirier, Dominique and Bujan, St{\'e}phane and Lecroart, Pascal} } @article {8644, title = {Coastal ocean acidification in Brazil: a brief overview and perspectives}, journal = {Arquivos de Ci{\^e}ncias do Mar}, volume = {55}, year = {2022}, month = {Sep-03-2023}, pages = {345 - 368}, issn = {0374-5686}, doi = {10.32360/acmar.v55iEspecial10.32360/acmar.v55iEspecial.78514}, url = {http://periodicos.ufc.br/arquivosdecienciadomar/issue/view/1159}, author = {Cotovicz Jr., Luiz C and Valente Marins, Rozane and Gwena{\"e}l Abril} } @article {8845, title = {Contrasting organic matter composition in pristine and eutrophicated mangroves revealed by fatty acids and stable isotopes (Rio de Janeiro, Brazil)}, journal = {Estuarine, Coastal and Shelf Science}, year = {2022}, month = {Jan-09-2022}, pages = {108061}, abstract = {Mangrove sediments have a high capacity of carbon storage, as the result of larger organic matter (OM) inputs from mangrove trees (litter fall and fine roots production) than OM microbial degradation and export to coastal waters. Mangrove sediments also act as traps for suspended matter and particulate OM (POM) from surrounding water masses. Fatty acids (FAs) markers, δ13C and δ15N signatures were used here to characterize the OM composition in three mangroves located in three coastal embayments of the Rio de Janeiro state (Brazil) with increasing urbanization from a pristine mangrove M1 to a moderately impacted mangrove M2 and a highly impacted mangrove M3. In these mangroves, the δ15N signature of tree leaves and sediments increases with anthropogenic influence, consistent with a large-scale eutrophication gradient along the three regions. At mangrove M1, predominant OM inputs from mangrove trees are highlighted by high proportions of long-chain fatty acids, particularly in the inland station, where high organic carbon concentrations (126\ {\textpm}\ 108\ mg\ g-1) indicate limited sedimentation of mineral particles and high carbon storage capacities. The sedimentary OM of M3 mangrove was more labile as confirmed by the higher proportions of algal fatty acids, enriched δ13C signature and the C/N ratio 1.6 times lower (p\ \<\ 0.001) than in the pristine mangrove M1. At the M2 mangrove site, high contribution of bacterial FAs (around 20\%) to sedimentary OM and high proportion of poorly biodegradable saturated fatty acids suggest that bacteria degrade algal labile OM in surface sediments but do not mineralize the most refractory fraction of OM. At the eutrophic M3 site, our findings suggest that deposition of labile POM induced an increase of fungal biomass on the sediment, apparently enhancing the microbial loop, and potentially leading to mineralization of refractory OM and carbon losses through a priming effect.}, issn = {02727714}, doi = {10.1016/j.ecss.2022.108061}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0272771422003195}, author = {Chynel, Mathias and Rockomanovic, Sofia and Gwena{\"e}l Abril and Barroso, Glenda and Marotta, Humberto and Machado, Wilson and Sanders, Christian J. and Najet Thiney and Tarik Meziane} } @article {8855, title = {Linking eutrophication to carbon dioxide and methane emissions from exposed mangrove soils along an urban gradient}, journal = {Science of The Total Environment}, volume = {850}, year = {2022}, month = {Jan-12-2022}, pages = {157988}, issn = {00489697}, doi = {10.1016/j.scitotenv.2022.157988}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0048969722050872}, author = {Barroso, Glenda C. and Gwena{\"e}l Abril and Machado, Wilson and Abuchacra, Rodrigo C. and Peixoto, Roberta B. and Bernardes, Marcelo and Marques, Gabriela S. and Sanders, Christian J. and Oliveira, Gabriela B. and Oliveira Filho, Silvio R. and Amora-Nogueira, Leonardo and Marotta, Humberto} } @article {8854, title = {Seasonal, Diurnal, and Tidal Variations of Dissolved Inorganic Carbon and pCO2 in Surface Waters of a Temperate Coastal Lagoon (Arcachon, SW France)}, journal = {Estuaries and Coasts}, year = {2022}, month = {Apr-09-2023}, issn = {1559-2723}, doi = {10.1007/s12237-022-01121-6}, url = {https://link.springer.com/10.1007/s12237-022-01121-6}, author = {Polsenaere, Pierre and Delille, Bruno and Poirier, Dominique and Charbonnier, C{\'e}line and Deborde, Jonathan and Mouret, Aur{\'e}lia and Gwena{\"e}l Abril} } @article {8643, title = {SPREADING EUTROPHICATION AND CHANGING CO2 FLUXES IN THE TROPICAL COASTAL OCEAN: A FEW LESSONS FROM RIO DE JANEIRO}, journal = {Arquivos de Ci{\^e}ncias do Mar}, volume = {55}, year = {2022}, month = {Sep-03-2023}, pages = {461 - 476}, issn = {0374-5686}, doi = {10.32360/acmar.v55iEspecial10.32360/acmar.v55iEspecial.78518}, url = {http://periodicos.ufc.br/arquivosdecienciadomar/issue/view/1159}, author = {Gwena{\"e}l Abril and C. Cotovicz Jr., Luiz and Nepomuceno, Aguinaldo and Erbas, Tha{\'\i}s and Costa, Suzan and V. Ramos, Vinicius and Moser, Gleyci and Fernandes, Alexandre and Negri, Eduardo and A. Knoppers, Bastiaan and Brandini, Nilva and Machado, Wilson and Bernardes, Marcelo and Vantrepotte, Vincent} } @article {8408, title = {A CO2 sink in a tropical coastal lagoon impacted by cultural eutrophication and upwelling}, journal = {Estuarine, Coastal and Shelf Science}, volume = {263}, year = {2021}, month = {Jan-12-2021}, pages = {107633}, issn = {02727714}, doi = {10.1016/j.ecss.2021.107633}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0272771421004820}, author = {Erbas, Tha{\'\i}s and Marques, Aguinaldo and Gwena{\"e}l Abril} } @proceedings {8068, title = {Establishing water sample protocols for radiocarbon analysis at LAC-UFF, Brazil}, year = {2021}, month = {09/2021}, pages = {1-8}, abstract = {Since the establishment of the first radiocarbon accelerator mass spectrometry facility in Latin America in 2009, the Radiocarbon Laboratory team of Universidade Federal Fluminense (LAC-UFF) has worked to improve sample preparation protocols and increase the range of environmental matrices to be analyzed. We now present the preliminary results for DIC sample preparation protocols. The first validation tests include background evaluation with pMC value (0.35 {\textpm} 0.04) using bicarbonate dissolved in water. We also analyzed surface seawater resulting in pMC value (101.38 {\textpm} 0.38) and a groundwater previously dated from LEMA AMS-Laboratory with pMC value (12.30 {\textpm} 0.15).}, issn = {0033-8222}, doi = {10.1017/RDC.2021.1}, url = {https://www.cambridge.org/core/product/identifier/S0033822221000011/type/journal_article}, author = {Bragan{\c c}a, Daniela and Oliveira, Fabiana and Macario, Kita and Nunes, Vinicius and Muniz, Marcelo and Lamego, Fernando and Gwena{\"e}l Abril and Nepomuceno, Aguinaldo and Sol{\'\i}s, Corina and Rodr{\'\i}guez-Ceja, Mar{\'\i}a} } @article {8106, title = {Eutrophication overcoming carbonate precipitation in a tropical hypersaline coastal lagoon acting as a CO2 sink (Araruama Lagoon, SE Brazil)}, journal = {Biogeochemistry}, year = {2021}, month = {Jun-08-2022}, issn = {0168-2563}, doi = {10.1007/s10533-021-00842-3}, url = {https://link.springer.com/10.1007/s10533-021-00842-3}, author = {Cotovicz, Luiz C. and Knoppers, Bastiaan A. and R{\'e}gis, Carolina R. and Tremmel, Daniel and Costa-Santos, Suzan and Gwena{\"e}l Abril} } @article {8067, title = {Greenhouse gas emissions (CO2 and CH4) and inorganic carbon behavior in an urban highly polluted tropical coastal lagoon (SE, Brazil)}, journal = {Environmental Science and Pollution Research}, year = {2021}, month = {04/2021}, issn = {0944-1344}, doi = {10.1007/s11356-021-13362-2}, url = {http://link.springer.com/10.1007/s11356-021-13362-2}, author = {Cotovicz, Luiz C. and Ribeiro, Renato P. and R{\'e}gis, Carolina Ramos and Bernardes, Marcelo and Sobrinho, Rodrigo and Vidal, Luciana Oliveira and Tremmel, Daniel and Knoppers, Bastiaan A. and Gwena{\"e}l Abril} } @article {8066, title = {Thermodynamic uptake of atmospheric CO2 in the oligotrophic and semiarid S{\~a}o Francisco estuary (NE Brazil)}, journal = {Marine Chemistry}, volume = {233}, year = {2021}, month = {01/2021}, pages = {103983}, issn = {03044203}, doi = {10.1016/j.marchem.2021.103983}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0304420321000682}, author = {Gwena{\"e}l Abril and Libardoni, Bruno G. and Brandini, Nilva and Cotovicz, Luiz C. and Medeiros, Paulo R.P. and Cavalcante, Ge{\'o}rgenes H. and Knoppers, Bastiaan A.} } @article {7203, title = {Carbon dioxide sources and sinks in the delta of the Para{\'\i}ba do Sul River (Southeastern Brazil) modulated by carbonate thermodynamics, gas exchange and ecosystem metabolism during estuarine mixing}, journal = {Marine Chemistry}, volume = {226}, year = {2020}, month = {Jan-10-2020}, pages = {103869}, issn = {03044203}, doi = {10.1016/j.marchem.2020.103869}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0304420320301237}, author = {Cotovicz, Luiz C. and Vidal, Luciana O. and de Rezende, Carlos Eduardo and Bernardes, Marcelo C. and Knoppers, Bastiaan A. and Sobrinho, Rodrigo L. and Cardoso, Renan P. and Muniz, Marcelo and dos Anjos, Roberto Meigikos and Biehler, Antoine and Gwena{\"e}l Abril} } @article {7204, title = {Denitrification and associated nitrous oxide and carbon dioxide emissions from the Amazonian wetlands}, journal = {Biogeosciences}, volume = {17}, year = {2020}, month = {Jan-01-2020}, pages = {4297 - 4311}, doi = {10.5194/bg-17-4297-2020}, url = {https://bg.copernicus.org/articles/17/4297/2020/}, author = {Guilhen, J{\'e}r{\'e}my and Al Bitar, Ahmad and Sauvage, Sabine and Parrens, Marie and Martinez, Jean-Michel and Gwena{\"e}l Abril and Moreira-Turcq, Patricia and S{\'a}nchez-P{\'e}rez, Jos{\'e}-Miguel} } @article {6579, title = {Comparing the efficiency of hypoxia mitigation strategies in an urban, turbid tidal river via a coupled hydro-sedimentary biogeochemical model}, journal = {Natural Hazards and Earth System Sciences}, volume = {19}, year = {2019}, month = {Jan-01-2019}, pages = {2551 - 2564}, doi = {10.5194/nhess-19-2551-2019}, url = {https://www.nat-hazards-earth-syst-sci.net/19/2551/2019/https://www.nat-hazards-earth-syst-sci.net/19/2551/2019/nhess-19-2551-2019.pdf}, author = {Lajaunie-Salla, Katixa and Sottolichio, Aldo and Schmidt, Sabine and Litrico, Xavier and Binet, Guillaume and Gwena{\"e}l Abril} } @article {5861, title = {Ideas and perspectives: Carbon leaks from flooded land: do we need to replumb the inland water active pipe?}, journal = {Biogeosciences}, volume = {16}, year = {2019}, month = {feb}, pages = {769{\textendash}784}, doi = {10.5194/bg-16-769-2019}, url = {https://doi.org/10.5194/bg-16-769-2019}, author = {Gwena{\"e}l Abril and Alberto V. Borges} } @article {5858, title = {Importance of the vegetation-groundwater-stream continuum to understand transformation of biogenic carbon in aquatic systems {\textendash} A case study based on a pine-maize comparison in a lowland sandy watershed (Landes de Gascogne, {SW} France)}, journal = {Science of The Total Environment}, volume = {661}, year = {2019}, month = {apr}, pages = {613{\textendash}629}, doi = {10.1016/j.scitotenv.2019.01.152}, url = {https://doi.org/10.1016/j.scitotenv.2019.01.152}, author = {Loris Deirmendjian and Pierre Anschutz and Christian Morel and Alain Mollier and Laurent Augusto and Denis Loustau and Luiz Carlos Cotovicz and Damien Buquet and Katixa Lajaunie and Gwena{\"e}lle Chaillou and Baptiste Voltz and C{\'e}line Charbonnier and Dominique Poirier and Gwena{\"e}l Abril} } @article {5998, title = {In vitro simulation of oscillatory redox conditions in intertidal sediments: N, Mn, Fe, and P coupling}, journal = {Continental Shelf Research}, year = {2019}, author = {Pierre Anschutz and Bouchet, Sylvain and Gwena{\"e}l Abril and Bridou, Romain and Tessier, Emmanuel and Amouroux, David} } @article {5868, title = {Sources and sinks of dissolved inorganic carbon in an urban tropical coastal bay revealed by δ13C-DIC signals}, journal = {Estuarine, Coastal and Shelf Science}, year = {2019}, author = {L.C. CotoviczJr and Knoppers, Bastiaan A and Deirmendjian, Loris and Gwena{\"e}l Abril} } @article {5860, title = {The transformation of macrophyte-derived organic matter to methane relates to plant water and nutrient contents}, journal = {Limnology and Oceanography}, year = {2019}, month = {mar}, doi = {10.1002/lno.11148}, url = {https://doi.org/10.1002/lno.11148}, author = {Charlotte Grasset and Gwena{\"e}l Abril and Raquel Mendon{\c c}a and Fabio Roland and Sebastian Sobek} } @article {5918, title = {Aragonite saturation state in a tropical coastal embayment dominated by phytoplankton blooms (Guanabara Bay - Brazil)}, journal = {Marine Pollution Bulletin}, volume = {129}, year = {2018}, pages = {729{\textendash}739}, doi = {10.1016/j.marpolbul.2017.10.064}, url = {https://doi.org/10.1016/j.marpolbul.2017.10.064}, author = {Luiz C. Cotovicz and Bastiaan A. Knoppers and Nilva Brandini and Dominique Poirier and Suzan J. Costa Santos and Gwena{\"e}l Abril} } @article {5920, title = {Carbon dioxide degassing at the groundwater-stream-atmosphere interface: isotopic equilibration and hydrological mass balance in a sandy watershed}, journal = {Journal of Hydrology}, volume = {558}, year = {2018}, pages = {129{\textendash}143}, doi = {10.1016/j.jhydrol.2018.01.003}, url = {https://doi.org/10.1016/j.jhydrol.2018.01.003}, author = {Loris Deirmendjian and Gwena{\"e}l Abril} } @article {5920, title = {Carbon dioxide degassing at the groundwater-stream-atmosphere interface: isotopic equilibration and hydrological mass balance in a sandy watershed}, journal = {Journal of Hydrology}, volume = {558}, year = {2018}, pages = {129{\textendash}143}, doi = {10.1016/j.jhydrol.2018.01.003}, url = {https://doi.org/10.1016/j.jhydrol.2018.01.003}, author = {Loris Deirmendjian and Gwena{\"e}l Abril} } @article {5917, title = {Carbon dynamics and CO2 and CH4 outgassing in the Mekong delta}, journal = {Biogeosciences}, volume = {15}, year = {2018}, pages = {1093{\textendash}1114}, doi = {10.5194/bg-15-1093-2018}, url = {https://doi.org/10.5194/bg-15-1093-2018}, author = {Alberto V. Borges and Gwena{\"e}l Abril and Steven Bouillon} } @article {5863, title = {Future intensification of summer hypoxia in the tidal Garonne River ({SW} France) simulated by a coupled hydro sedimentary-biogeochemical model}, journal = {Environmental Science and Pollution Research}, volume = {25}, year = {2018}, month = {sep}, pages = {31957{\textendash}31970}, doi = {10.1007/s11356-018-3035-6}, url = {https://doi.org/10.1007/s11356-018-3035-6}, author = {Katixa Lajaunie-Salla and Aldo Sottolichio and Sabine Schmidt and Xavier Litrico and Guillaume Binet and Gwena{\"e}l Abril} } @article {5921, title = {Hydro-ecological controls on dissolved carbon dynamics in groundwater and export to streams in a temperate pine forest}, journal = {Biogeosciences}, volume = {15}, year = {2018}, pages = {669{\textendash}691}, doi = {10.5194/bg-15-669-2018}, url = {https://doi.org/10.5194/bg-15-669-2018}, author = {Loris Deirmendjian and Denis Loustau and Laurent Augusto and S{\'e}bastien Lafont and Christophe Chipeaux and Dominique Poirier and Gwena{\"e}l Abril} } @article {5921, title = {Hydro-ecological controls on dissolved carbon dynamics in groundwater and export to streams in a temperate pine forest}, journal = {Biogeosciences}, volume = {15}, year = {2018}, pages = {669{\textendash}691}, doi = {10.5194/bg-15-669-2018}, url = {https://doi.org/10.5194/bg-15-669-2018}, author = {Loris Deirmendjian and Denis Loustau and Laurent Augusto and S{\'e}bastien Lafont and Christophe Chipeaux and Dominique Poirier and Gwena{\"e}l Abril} } @article {5862, title = {Invasive Aquatic Plants as Ecosystem Engineers in an Oligo-Mesotrophic Shallow Lake}, journal = {Frontiers in Plant Science}, volume = {9}, year = {2018}, month = {dec}, doi = {10.3389/fpls.2018.01781}, url = {https://doi.org/10.3389/fpls.2018.01781}, author = {Cristina Ribaudo and Juliette Tison-Rosebery and Damien Buquet and Gwilherm Jan and Aur{\'e}lien Jamoneau and Gwena{\"e}l Abril and Pierre Anschutz and Vincent Bertrin} } @article {5864, title = {{OZCAR}: The French Network of Critical Zone Observatories}, journal = {Vadose Zone Journal}, volume = {17}, year = {2018}, doi = {10.2136/vzj2018.04.0067}, url = {https://doi.org/10.2136/vzj2018.04.0067}, author = {J. Gaillardet and I. Braud and F. Hankard and S. Anquetin and O. Bour and N. Dorfliger and J.R. de Dreuzy and S. Galle and C. Galy and S. Gogo and L. Gourcy and F. Habets and F. Laggoun and L. Longuevergne and T. Le Borgne and F. Naaim-Bouvet and G. Nord and V. Simonneaux and D. Six and T. Tallec and C. Valentin and Gwena{\"e}l Abril and P. Allemand and A. Ar{\`e}nes and B. Arfib and L. Arnaud and N. Arnaud and P. Arnaud and S. Audry and V. Bailly Comte and C. Batiot and A. Battais and H. Bellot and E. Bernard and C. Bertrand and H. Bessi{\`e}re and S. Binet and J. Bodin and X. Bodin and L. Boithias and J. Bouchez and B. Boudevillain and I. Bouzou Moussa and F. Branger and J. J. Braun and P. Brunet and B. Caceres and D. Calmels and B. Cappelaere and H. Celle-Jeanton and F. Chabaux and K. Chalikakis and C. Champollion and Y. Copard and C. Cotel and P. Davy and P. Deline and G. Delrieu and J. Demarty and C. Dessert and M. Dumont and C. Emblanch and J. Ezzahar and M. Est{\`e}ves and V. Favier and M. Faucheux and N. Filizola and P. Flammarion and P. Floury and O. Fovet and M. Fournier and A. J. Francez and L. Gandois and C. Gascuel and E. Gayer and C. Genthon and M. F. G{\'e}rard and D. Gilbert and I. Gouttevin and M. Grippa and G. Gruau and A. Jardani and L. Jeanneau and J. L. Join and H. Jourde and F. Karbou and D. Labat and Yvan Lagadeuc and E. Lajeunesse and R. Lastennet and W. Lavado and E. Lawin and T. Lebel and C. Le Bouteiller and C. Legout and Y. Lejeune and E. Le Meur and N. Le Moigne and J. Lions and A. Lucas and J. P. Malet and C. Marais-Sicre and J. C. Mar{\'e}chal and C. Marlin and P. Martin and J. Martins and J. M. Martinez and N. Massei and A. Mauclerc and N. Mazzilli and J. Mol{\'e}nat and P. Moreira-Turcq and E. Mougin and S. Morin and J. Ndam Ngoupayou and G. Panthou and C. Peugeot and G. Picard and M. C. Pierret and G. Porel and A. Probst and J. L. Probst and A. Rabatel and D. Raclot and L. Ravanel and F. Rejiba and P. Ren{\'e} and O. Ribolzi and J. Riotte and A. Rivi{\`e}re and H. Robain and L. Ruiz and J. M. Sanchez-Perez and W. Santini and S. Sauvage and P. Schoeneich and J. L. Seidel and M. Sekhar and O. Sengtaheuanghoung and N. Silvera and M. Steinmann and A. Soruco and G. Tallec and E. Thibert and D. Valdes Lao and C. Vincent and D. Viville and P. Wagnon and R. Zitouna} } @article {5919, title = {Predominance of phytoplankton-derived dissolved and particulate organic carbon in a highly eutrophic tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil)}, journal = {Biogeochemistry}, volume = {137}, year = {2018}, pages = {1{\textendash}14}, doi = {10.1007/s10533-017-0405-y}, url = {https://doi.org/10.1007/s10533-017-0405-y}, author = {Luiz C. Cotovicz and Bastiaan A. Knoppers and Nilva Brandini and Dominique Poirier and Suzan J. Costa Santos and Renato C. Cordeiro and Gwena{\"e}l Abril} } @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 {4176, title = {Spatial and seasonal contrasts of sedimentary organic matter in floodplain lakes of the central Amazon basin}, journal = {Biogeosciences}, volume = {13}, year = {2016}, type = {original}, abstract = {
In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter (SOM) in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Cana{\c c}ari, Mirituba and Curuai) which have different morphologies, hydrodynamics and vegetation coverages. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We inves-tigated commonly used bulk geochemical tracers such as the C/N ratio and the stable isotopic composition of organic carbon (13Cor). These results were compared with lignin phenol parameters as an indicator of vascular plant detritus and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the input of soil organic matter (OM) from land to the aquatic settings. We also applied the crenarchaeol as an indi- cator of aquatic (rivers and lakes) OM. Our data showed that during the RW and FW seasons, the surface sediments were enriched in lignin and brGDGTs in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of allochthonous, C3 plant-derived OM. However, a downstream increase in C4 macrophyte-derivedOM contribution was observed along the gradient of increas-ing open waters {\textendash} i.e., from upstream to downstream. Accordingly, we attribute the temporal and spatial difference in SOM composition to the hydrological dynamics between the floodplain lakes and the surrounding flooded forests.
\