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2. List of Contributors

Author

Abbas, B., primary, Abreu, A., additional, Adams, R., additional, Adolfsson-Erici, M., additional, Afonso, A., additional, Afonso-Olivares, C., additional, Agirbas, E., additional, Aguiló, J.M., additional, Airoldi, L., additional, Aksoy, H., additional, Albentosa, M., additional, Alcaro, L., additional, Aliani, S., additional, Al-Maslamani, I., additional, Alomar, C., additional, Altin, D., additional, Álvarez, E., additional, Amaral-Zettler, L.A., additional, Amato, E., additional, Anderson, A., additional, Andrady, A.L., additional, Andrius, G., additional, Angel, D., additional, Ariese, F., additional, Arp, H.P., additional, Asensio, M., additional, Assidqi, K., additional, Avio, C.G., additional, Aytan, U., additional, Bahri, T., additional, Baini, M., additional, Bakir, A., additional, Ball, H., additional, Baranyi, C., additional, Barboza, L.G.A., additional, Barg, U., additional, Bargelloni, L., additional, Barras, H., additional, Barrera, C., additional, Barria, P., additional, Barrows, A., additional, Barth, A., additional, Batel, A., additional, Baztan, J., additional, Baztan, P., additional, Beiras, R., additional, Benedetti, M., additional, Berber, A.A., additional, Berber, N., additional, Bergmann, M., additional, Berlino, M., additional, Berrow, S., additional, Bessa, F., additional, Besseling, E., additional, Beyer, B., additional, Binaglia, M., additional, Bizjak, T., additional, Bjorndal, K.A., additional, Blust, R., additional, Boertien, M., additional, Bolten, A.B., additional, Booth, A.M., additional, Bounoua, B., additional, Bourseau, P., additional, Brahimi, N., additional, Bramini, M., additional, Brennholt, N., additional, Breuninger, E., additional, Bried, J., additional, Broderick, A., additional, Broglio, E., additional, Browne, M.A., additional, Bruzaud, S., additional, Buceta, J., additional, Buchinger, S., additional, Budimir, S., additional, Budzin-ski, H., additional, Butter, E., additional, Cachot, J., additional, Caetano, M., additional, Callaghan, A., additional, Camedda, A., additional, Capella, S., additional, Cardelli, L., additional, Carpentieri, S., additional, Carrasco, A., additional, Carriço, R., additional, Caruso, A., additional, Cassone, A.-L., additional, Castillo, A., additional, Castro, R.O., additional, Catarino, A.I., additional, Cazenave, P.W., additional, Çelik, İ., additional, Cerralbo, P., additional, César, G., additional, Chouinard, O., additional, Chubarenko, I., additional, Chubarenko, I.P., additional, Cicero, A.M., additional, Clarindo, G., additional, Clarke, B., additional, Clérandeau, C., additional, Clüsener-Godt, M., additional, Codina-García, M., additional, Cole, M., additional, Collard, F., additional, Collignon, A., additional, Collins, T., additional, Compa, M., additional, Conan, P., additional, Constant, M., additional, Cordier, M., additional, Courtene-Jones, W., additional, Cousin, X., additional, Covelo, P., additional, Cózar, A., additional, Crichton, E., additional, Crispi, O., additional, Cronin, M., additional, Croot, P.L., additional, Cruz, M.J., additional, d’Errico, G., additional, Dâmaso, C., additional, Das, K., additional, de Alencastro, L.F., additional, de Araujo, F.V., additional, de Boer, J.F., additional, de Lucia, G.A., additional, Debeljak, P., additional, Dehaut, A., additional, Deudero, S., additional, Devrieses, L., additional, Di Vito, S., additional, Díaz, A., additional, Donohue, J., additional, Doumenq, P., additional, Doyle, T.K., additional, Dris, R., additional, Druon, J.-N., additional, Duarte, C.M., additional, Duflos, G., additional, Dumontier, M., additional, Duncan, E., additional, Dussud, C., additional, Eckerlebe, A., additional, Egelkraut-Holtus, M., additional, Eidsvoll, D.P., additional, Ek, C., additional, Elena, S., additional, Elineau, A., additional, Enevoldsen, H., additional, Eppe, G., additional, Eriksen, M., additional, Ernsteins, R., additional, Espino, M., additional, Estévez-Calvar, N., additional, Ewins, C., additional, Fabre, P., additional, Faimali, M., additional, Fattorini, D., additional, Faure, F., additional, Ferrando, S., additional, Ferreira, J.C., additional, Ferreira-da-Costa, M., additional, Fileman, E., additional, Fischer, M., additional, Fortunato, A.B., additional, Fossi, M.C., additional, Foulon, V., additional, Frank, A., additional, Frenzel, M., additional, Frère, L., additional, Frias, J.P.G.L., additional, Frick, H., additional, Froneman, P.W., additional, Gabet, V.M., additional, Gabrielsen, G.W., additional, Gago, J., additional, Gajst, T., additional, Galgani, F., additional, Gallinari, M., additional, Galloway, T.S., additional, Gamarro, E.G., additional, Gambardella, C., additional, Garaventa, F., additional, Garcia, S., additional, Garrabou, J., additional, Garrido, P., additional, Gary, S.F., additional, Gasperi, J., additional, Gaze, W., additional, Geertz, T., additional, Gelado-Caballero, M.D., additional, George, M., additional, Gercken, J., additional, Gerdts, G., additional, Ghiglione, J.-F., additional, Gies, E., additional, Gilbert, B., additional, Giménez, L., additional, Glassom, D., additional, Glockzin, M., additional, Godley, B., additional, Goede, K., additional, Goksøyr, A., additional, Gómez, M., additional, Gómez-Parra, A., additional, González-Marco, D., additional, González-Solís, J., additional, Gorbi, S., additional, Gorokhova, E., additional, Gorsky, G., additional, Gosch, M., additional, Grose, J., additional, Guebitz, G.M., additional, Guedes-Alonso, R., additional, Guijarro, B., additional, Guilhermino, L., additional, Gundry, T., additional, Gutow, L., additional, Haave, M., additional, Haeckel, M., additional, Haernvall, K., additional, Hajbane, S., additional, Hamann, M., additional, Hämer, J., additional, Hamm, T., additional, Hansen, B.H., additional, Hardesty, B.D., additional, Harth, B., additional, Hartikainen, S., additional, Hassellöv, M., additional, Hatzky, S., additional, Healy, M.G., additional, Hégaret, H., additional, Henry, T.B., additional, Hermabessiere, L., additional, Hernández-Brito, J.J., additional, Hernandez-Gonzalez, A., additional, Hernandez-Milian, G., additional, Hernd, G., additional, Herrera, A., additional, Herring, C., additional, Herzke, D., additional, Heussner, S., additional, Hidalgo-Ruz, V., additional, Himber, C., additional, Holland, M., additional, Hong, N.-H., additional, Horton, A.A., additional, Horvat, P., additional, Huck, T., additional, Huhn, M., additional, Huvet, A., additional, Iglesias, M., additional, Igor, C., additional, Isachenko, I.A., additional, Ivar do Sul, J-A., additional, Jahnke, A., additional, Janis, B., additional, Janis, K., additional, Janis, U., additional, Jemec, A., additional, Jiménez, J.C., additional, Johnsen, H., additional, Jorgensen, B., additional, Jørgensen, J.H., additional, Jörundsdóttir, H., additional, Jung, Y.-J., additional, Kedzierski, M., additional, Keiter, S., additional, Kershaw, P., additional, Kerhervé, P., additional, Kesy, K., additional, Khan, F., additional, Khatmullina, L.I., additional, Kirby, J., additional, Kiriakoulakis, K., additional, Klein, R., additional, Klunderud, T., additional, Knudsen, C.M.H., additional, Knudsen, T.B., additional, Kochleus, C., additional, Koelmans, A.A., additional, Kögel, T., additional, Koistinen, A., additional, Kopke, K., additional, Korez, Š., additional, Kowalski, N., additional, Kreikemeyer, B., additional, Kroon, F., additional, Krumpen, T., additional, Krzan, A., additional, Kržan, A., additional, Labrenz, M., additional, Lacroix, C., additional, Ladirat, L., additional, Laforsch, C., additional, Lagarde, F., additional, Lahive, E., additional, Lambert, C., additional, Lapucci, C., additional, Lattin, G., additional, Law, K.L., additional, Le Roux, F., additional, Le Souef, K., additional, Le Tilly, V., additional, Lebreton, L., additional, Leemans, E., additional, Lehtiniemi, M., additional, Lenz, M., additional, Leskinen, J., additional, Leslie, H., additional, Leslie, H.A., additional, Levasseur, C., additional, Lewis, C., additional, Licandro, P., additional, Lind, K., additional, Lindeque, P., additional, Lindeque, P.K., additional, Lips, I., additional, Liria, A., additional, Liria-Loza, A., additional, Llinás, O., additional, Loiselle, S.A., additional, Long, M., additional, Lorenz, C., additional, Lorenzo, S.M., additional, Loubar, K., additional, Luna-Jorquera, G., additional, Lusher, A.L., additional, Macchia, V., additional, MacGabban, S., additional, Mackay, K., additional, MacLeod, M., additional, Maes, T., additional, Magaletti, E., additional, Maggiore, A., additional, Magnusson, K., additional, Mahon, A.M., additional, Makorič, P., additional, Mallow, O., additional, Marques, J., additional, Marsili, L., additional, Martí, E., additional, Martignac, M., additional, Martin, J., additional, Martínez, I., additional, Martínez, J., additional, Martinez-Gil, M., additional, Martins, H.R., additional, Matiddi, M., additional, Maximenko, N., additional, Mazlum, R., additional, Mcadam, R., additional, Mcknight, L., additional, McNeal, A.W., additional, Measures, J., additional, Mederos, M.S., additional, Mendoza, J., additional, Meyer, M.S., additional, Miguelez, A., additional, Milan, M., additional, Militão, T., additional, Miller, R.Z., additional, Mino-Vercellio-Verollet, M., additional, Mir, G., additional, Miranda-Urbina, D., additional, Misurale, F., additional, Montesdeoca-Esponda, S., additional, Mora, J., additional, Morgana, S., additional, Moriceau, B., additional, Morin, B., additional, Morley, A., additional, Morrison, L., additional, Murphy, F., additional, Naidoo, T., additional, Näkki, P., additional, Napper, I.E., additional, Narayanaswamy, B.E., additional, Nash, R., additional, Negri, A., additional, Nel, H.A., additional, Nerheim, M.S., additional, Nerland, I.L., additional, Neto, J., additional, Neves, V., additional, Nies, H., additional, Noel, M., additional, Nor, N.H.M., additional, Noren, F., additional, O’ Connell, B., additional, O’ Connor, I., additional, Obbard, J.P., additional, Oberbeckmann, S., additional, Obispo, R., additional, Officer, R., additional, Ogonowski, M., additional, Orbea, A., additional, Ortlieb, M., additional, Osborn, A.M., additional, Ostiategui-Francia, P., additional, Packard, T., additional, Pahl, S., additional, Palatinus, A., additional, Palmqvist, A., additional, Pannetier, P., additional, Panti, C., additional, Parmentier, E., additional, Pasanen, P., additional, Patarnello, T., additional, Pattiaratchi, C., additional, Pauletto, M., additional, Paulus, M., additional, Pavlekovsky, K., additional, Pedersen, H.B., additional, Pedrotti, M.-L., additional, Peeken, I., additional, Peeters, D., additional, Peeters, E., additional, Pellegrini, D., additional, Perales, J.A., additional, Perez, E., additional, Perz, V., additional, Petit, S., additional, Pflieger, M., additional, Pham, C.K., additional, Piazza, V., additional, Pinto, M., additional, Planells, O., additional, Plaza, M., additional, Pompini, O., additional, Potthoff, A., additional, Prades, L., additional, Primpke, S., additional, Proietti, M., additional, Proskurowski, G., additional, Puig, C., additional, Pujo-Pay, M., additional, Pullerits, K., additional, Queirós, A.M., additional, Quinn, B., additional, Raimonds, E., additional, Ramis-Pujol, J., additional, Rascher-Friesenhausen, R., additional, Reardon, E., additional, Regoli, F., additional, Reichardt, A.M., additional, Reifferscheid, G., additional, Reilly, K., additional, Reisser, J., additional, Riba, I., additional, Ribitsch, D., additional, Rinnert, E., additional, Rios, N., additional, Rist, S.E., additional, Rivadeneira, M.M., additional, Rivière, G., additional, Robbens, J., additional, Robertson, C.J.R., additional, Rocher, V., additional, Rochman, C.M., additional, Rodrigues, M., additional, Rodriguez, Y., additional, Rodríguez, A., additional, Rodríguez, G., additional, Rodríguez, J.R.B., additional, Rodríguez, S., additional, Rodríguez, Y., additional, Rogan, E., additional, Rojo-Nieto, E., additional, Romeo, T., additional, Ross, P.S., additional, Roveta, A., additional, Rowland, S.J., additional, Ruckstuhl, N.A., additional, Ruiz-Fernández, A-C., additional, Ruiz-Orejón, L.F., additional, Runge, J., additional, Russell, M., additional, Saavedra, C., additional, Saborowski, R., additional, Sahin, B.E., additional, Sailley, S., additional, Sakaguchi-Söder, K., additional, Salaverria, I., additional, Sánchez-Arcilla, A., additional, Sánchez-Nieva, J., additional, Sanderson, W., additional, Santana-Rodríguez, J.J., additional, Santana-Viera, S., additional, Santos, M.B., additional, Santos, M.R., additional, Sanz, M.R., additional, Sardá, R., additional, Savelli, H., additional, Schoeneich-Argent, R., additional, Scholz-Böttcher, B.M., additional, Sciacca, F., additional, Scofield, R.P., additional, Setälä, O., additional, Selenius, M., additional, Sempere, R., additional, Senturk, Y., additional, Shashoua, Y., additional, Sherman, P., additional, Sick, C., additional, Siegel, D., additional, Sierra, J.P., additional, Silva, F., additional, Silvestri, C., additional, Sintija, G., additional, Sire, O., additional, Slat, B., additional, Smit, A., additional, Sobral, P., additional, Sorvari, J., additional, Sosa-Ferrera, Z., additional, Sotillo, M.G., additional, Soudant, P., additional, Speidel, L., additional, Spurgeon, D.J., additional, Steer, M.K., additional, Steindal, C.C., additional, Stifanese, R., additional, Štindlová, A., additional, Stuurman, L., additional, Suaria, G., additional, Suazo, C.G., additional, Sureda, A., additional, Surette, C., additional, Svendsen, C., additional, Syberg, K., additional, Tairova, Z., additional, Talvitie, J., additional, Tassin, B., additional, Tazerout, M., additional, Tekman, M.B., additional, ter Halle, A., additional, Thiel, M., additional, Thomas, K.V., additional, Thompson, R.C., additional, Tinkara, T., additional, Tirelli, V., additional, Tomassetti, P., additional, Toorman, E., additional, Toppe, J., additional, Tornambè, A., additional, Torres, R., additional, Torres-Padrón, M.E., additional, Underwood, A.J., additional, Urbina, M., additional, Usategui-Martín, A., additional, Usta, R., additional, Valdés, L., additional, Valente, A., additional, Valentina, T., additional, van Arkel, K., additional, Van Colen, C., additional, Van Der Hal, N., additional, van Franeker, J.A., additional, Van Herwerden, L., additional, Van Loosdrecht, M., additional, van Oyen, A., additional, Vandeperre, F., additional, Vanderlinden, J-P., additional, Vani, D., additional, Vasconcelos, L., additional, Vega-Moreno, D., additional, Ventero, A., additional, Vethaak, A.D., additional, Vianello, A., additional, Vicioso, M., additional, Vieira, L.R., additional, Viršek, M.K., additional, Vos, M., additional, Wahl, M., additional, Wallace, N., additional, Walton, A., additional, Waniek, J.J., additional, Watts, A., additional, Webster, L., additional, Wesch, C., additional, Whitfield, E., additional, Wichels, A., additional, Wieczorek, A.M., additional, Wilcox, C., additional, Williams, R.J., additional, Wong-Wah-Chung, P., additional, Wright, S., additional, Wyles, K.J., additional, Young, R., additional, Yurtsever, M., additional, Yurtsever, U., additional, Zada, L., additional, Zamani, N.P., additional, and Zampetti, G., additional

Published
2017
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8. Bi-decadal variability in physico-biogeochemical characteristics of temperate coastal ecosystems: from large-scale to local drivers

Author

Lheureux, A, primary, Savoye, N, additional, Del Amo, Y, additional, Goberville, E, additional, Bozec, Y, additional, Breton, E, additional, Conan, P, additional, L’Helguen, S, additional, Mousseau, L, additional, Raimbault, P, additional, Rimelin-Maury, P, additional, Seuront, L, additional, Vuillemin, R, additional, Caparros, J, additional, Cariou, T, additional, Cordier, MA, additional, Corre, AM, additional, Costes, L, additional, Crispi, O, additional, Crouvoisier, M, additional, Derriennic, H, additional, Devesa, J, additional, Durozier, M, additional, Ferreira, S, additional, Garcia, N, additional, Grossteffan, E, additional, Gueux, A, additional, Lafont, M, additional, Lagadec, V, additional, Lecuyer, E, additional, Leroux, C, additional, Macé, E, additional, Maria, E, additional, Mornet, L, additional, Nowaczyk, A, additional, Parra, M, additional, Petit, F, additional, and David, V, additional

Published
2021
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9. Steam and gas emission rates from La Soufrière of Guadeloupe (Antilles arc): implications for the magmatic supply degassing during unrest

Author

Allard, P, AIUPPA, Alessandro, Beauducel, F, CALABRESE, Sergio, DI NAPOLI, Rossella, Crispi, O, Gaudin, D, PARELLO, Francesco, Hammouya, G, TAMBURELLO, Giancarlo, Allard, P, Aiuppa, A, Beauducel, F, Calabrese, S, Di Napoli, R, Crispi, O, Gaudin, D, Parello, F, Hammouya, G, and Tamburello, G

Subjects
Guadeloupe, volcanoes, volcanic degassing, Settore GEO/08 - Geochimica E Vulcanologia
Abstract

Since its last magmatic eruption in 1530 AD, La Soufrière andesitic volcano in Guadeloupe has displayed intense hydrothermal activity and six phreatic eruptive crises (the last of which, in 1976-1977, with 73000 evacuees). Here we report on the first direct quantification of gas plume emissions from La Soufrière summit vents, which gradually intensified during the past 20 years. Gas fluxes were determined in 2006 then 2012 [1] by measuring the horizontal and vertical distribution of volcanic gas concentrations in the air-diluted plume, the composition of the hot fumarolic fluid at exit (108°C), and scaling to the speed of plume transport (in situ measurements and FLIR imaging). We first demonstrate that all fumarolic vents of La Soufrière are fed by a common H2O-rich (97-98 mol %) fluid end-member, emitted almost unmodified at the most active South Crater while affected by secondary alterations (steam condensation, sulphur scrubbing) at other vents. Daily fluxes in 2012 (200 tons of H2O, 15 tons of CO2, ~4 tons of H2S and 1 ton of HCl) were augmented by a factor ~3 compared to 2006, in agreement with increasing activity. Summit fumarolic degassing contributes most of the bulk volatile and heat budget (8 MW) of the volcano. Isotopic evidences demonstrate that La Soufrière hydrothermal emissions are sustained by continuous heat and gas supply from an andesitic magma reservoir confined at 6-7 km depth. This magmatic supply mixes with abundant groundwater of tropical meteoric origin in the hydrothermal system. Based on petro-geochemical data for the erupted magma(s), we assess that the volcanic gas fluxes in 2012 can be accounted for by the release of free magmatic gas derived from about 1000 m3 per day of the basaltic melt replenishing the reservoir at depth. In terms of mass budget, the current degassing unrest is compatible with enhanced free gas release from that reservoir, without requiring any (actually undetected) magma intrusion. We recommend a regular survey of the fumarolic gas flux from La Soufrière in order to anticipate the evolution of the magma reservoir. [1] P. Allard et al., Chemical Geology 384, 76-93, 2014.

Published
2015

10. Steam and gas emission rate from La Soufriere volcano, Guadeloupe (Lesser Antilles): implications for the magmatic and hydrothermal fluid supply during degassing unrest

Author

Allard, P., Aiuppa, A., Beauducel, F., Gaudin, D., Di Napoli, R., Crispi, O., Calabrese, S., Parello, F., Hammouya, G., Tamburello, G., Allard, P, Aiuppa A, Beauducel, F, Gaudin, D, Di Napoli, R, Crispi, O, Calabrese, S, Parello, F, Hammouya, G, and Tamburello, G

Subjects
Soufrière of Guadeloupe, Volcanic gas fluxes, Heat output, Magma degassing budget, Volcanic hazard, Settore GEO/08 - Geochimica E Vulcanologia
Abstract

Since its last magmatic eruption in 1530 AD, La Soufrière andesitic volcano in Guadeloupe has displayed intense hydrothermal activity and six phreatic eruptive crises. Here we report on the first direct quantification of gas plume emissions from its summit vents,which gradually intensified during the past 20 years. Gas fluxes were determined in March 2006 and March 2012 by measuring the horizontal and vertical distributions of volcanic gas concentrations in the air-diluted plume and scaling to the speed of plume transport. Fluxes in 2006 combine realtime measurements of volcanic H2S concentrations and plume parameters with the composition of the hot (108.5 °C) fumarolic fluid at exit. Fluxes in 2012 result from MultiGAS analysis of H2S, H2O, CO2, SO2 and H2 concentrations, combined with thermal imaging of the plume geometry and dynamics. Measurementswere not only focused on the most active South crater (SC) vent, but also targeted Tarissan crater and other reactivating vents. We first demonstrate that all vents are fed by a common H2O-rich (97–98 mol%) fluid end-member, emitted almost unmodified at SC but affected by secondary shallow alterations at other vents. Daily fluxes in 2012 averaged 200 tons of H2O, 15 tons of CO2, ~4 tons of H2S and 1 ton of HCl, increased by a factor ~3 compared to 2006. Even though modest, such fluxes make La Soufrière the second most important volcanic gas emitter in the Lesser Antilles arc, after Soufriere Hills of Montserrat. Taking account of other hydrothermal manifestations (hot springs and diffuse soil degassing), the summit fumarolic activity is shown to contribute most of the bulk volatile and heat budget of the volcano. The hydrothermal heat output (8MW) exceeds by orders of magnitude the contemporaneous seismic energy release. Isotopic evidences support that La Soufrière hydrothermal emissions are sustained by a variable but continuous heat and gas supply from a magma reservoir confined at 6–7 km depth. By using petro-geochemical data for La Soufrière magma(s) and their dissolved volatile content, and assuming a magmatic derivation of sulfur, we estimate that the volcanic gas fluxes measured in 2012 could result from the underground release of magmatic gas exsolved from ~1400 m3 d−1 of basaltic melt feeding the system at depth. We recommend that fumarolic gas flux at La Soufrière becomes regularly measured in the future in order to carefully monitor the temporal evolution of that magmatic supply.

Published
2014

11. Controls on chemical weathering on a mountainous volcanic tropical island: Guadeloupe (French West Indies)

Author

Dessert, C., Lajeunesse, 'E., Lloret, Emily, Clergue, C., Crispi, O., Gorge, C., Quidelleur, X., Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Génie Civil et Géo-Environnement [Béthune] (LGCgE), Université d'Artois (UA), Laboratoire GéoSciences Réunion (LGSR), Université de La Réunion (UR)-Institut de Physique du Globe de Paris, Géosciences Paris Sud (GEOPS), and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU]Sciences of the Universe [physics]
Abstract

International audience; Guadeloupe Island is a natural laboratory, ideally suited to the study of biogeochemical processes in tropical and mountainous volcanic environments. The island’s east–west rainfall gradient (1200–8000 mm/yr) is superimposed on a north–south age gradient (2.7 Ma to present), providing a unique opportunity to investigate the influence of rainfall and rock age on the chemical weathering of volcanic terrains. Taking advantage of this configuration, we present the first temporal survey (2007–2013) of the geochemical composition of the dissolved load of rain and river waters in Guadeloupe. Our data demonstrate that the chemical composition of river water is influenced by rainfall abundance, hydrothermal alteration (from active or fossilized volcanic systems) and interactions between water and minerals during chemical weathering processes. The contribution of rain to the overall chemical balance is especially significant in the older northern part of the island, where the ferralitic soils are base-cation-depleted. Between 15% and 65% of the Ca or Mg riverine budgets comes from atmospheric deposits, highlighting the major role of rainfall in the geochemical budgets of small tropical and mountainous watersheds. The river water dataset indicates that different chemical weathering processes dominate the budget depending on the age of the local bedrock. In the younger, southern part of the island, a pool of easily-weatherable andesitic minerals from the bedrock dominates. The contribution from this pool decreases significantly (to 5–15 wt.% of the bulk soil) towards the older terrains in the north. The northern rivers are characterized by low Ca/Mg ratios (0.5–1.0), intermediate between those of fresh rocks (1.7–3.3) and soil (0.1). Weathering in the northern part of the island is therefore dominated by the dissolution of depleted secondary minerals into soils. The Ca/Mg ratio of the river water increases from north to south, eventually reaching values similar to those of the bedrocks, arguing for congruent dissolution of the youngest volcanic rocks. The magnesium isotopic composition of river water (δ26Mg) reflects inputs from both rain and weathering processes. In southern and central rivers, the Mg isotopic value of waters after correction for rain inputs (δ26Mgwea) is systematically depleted in heavy isotopes (mean value of −0.34‰) relative to that of the bedrock (−0.24‰ to −0.15‰). In the north, the δ26Mgwea of the river water (−0.09‰) is heavier than that of the andesitic bedrock, possibly reflecting the dissolution of 26Mg-rich secondary minerals (ferralitic soil measured around +0.13‰). The robustness of δ26Mg and Ca/Mg as proxies of the degree of soil weathering should be investigated further via more detailed sampling campaigns in the future. By combining high-frequency monitoring of river discharge with measurements of concentration–discharge relationships for a wide range of chemical elements, we estimate the mean annual chemical weathering fluxes for three rivers that belong to the OBSERA critical zone observatory. Fluxes vary from 51.7 to 91.8 t/km2/yr north to south along the bedrock age gradient, and are among the highest recorded in volcanic tropical regions. Flash floods can explain 21–31% of the annual chemical weathering fluxes. The results highlight the importance of monitoring rivers over periods of several years in order to obtain accurate estimates of chemical exports in tropical and mountainous environments.

Published
2015

14. Comparison of dissolved inorganic and organic carbon export in the rivers of tropical volcanic island; example from Guadeloupe, French West Indies

Author

Lloret, E., Dessert, C., Gaillardet, J., Albéric, Patrick, Crispi, O., Chaduteau, C., Benedetti, M. F., Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), and Université de Tours-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Carbon cycling, [0454] BIOGEOSCIENCES, [0428] BIOGEOSCIENCES, Erosion, [SDE.MCG]Environmental Sciences/Global Changes, Isotopic composition and chemistry, [1806] HYDROLOGY, Chemistry of fresh water, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [1815] HYDROLOGY
Abstract

International audience; Organic matter is an important factor that cannot be neglected when considering global carbon cycle. New data including organic matter geochemistry at the small watershed scale are needed to elaborate more constrained carbon dynamic and climatic models. The objectives are to estimate the DOC and DIC fluxes in well constrained geochemical systems that are small tropical rivers and to characterize and identify the different sources of the organic carbon exported under different hydrological regime (i.e. low water level vs flood level). To answer these questions, we have studied the geochemistry of eleven small watersheds around Basse-Terre Island in the French West Indies during different hydrological regime from 2006 to 2008. Together with water discharge, DOC concentrations, DIC concentrations were measured as well as their isotopic composition (δ13CDOC and δ13CDIC). Spectroscopic indicators of the nature of the organic matter are used to characterize the sources of DOC in the rivers. The ratio DOC/DIC varied between 0.070 and 1.971, with the highest values corresponding to flood conditions, indicating that these rivers export more organic matter during the flood events. The isotopic composition of DOC, ranged from -33.5 to -29.5 ‰ during low water level and from -30.1 to -27.2 ‰ during flood levels, indicates that rivers are fed by different sources during these two hydrological stages. During low water level the rivers were mainly fed by perennial groundwater flow, while during flood level the rivers were fed by lixiviation of top soil solutions. The mean annual fluxes ranged from 2.5 to 5.7 t km-2 yr-1 for the DOC and from 4.8 to 19.6 t km-2 yr-1 for the DIC. The DOC/DIC ratios exhibit a non-linear relationship with the slopes of watershed. Our results emphasize the importance of DOC fluxes in the carbon mass balance in small tropical rivers.

Published
2010

17. Are small mountainous tropical watersheds of oceanic islands important for carbon export?

Author

Lloret, E., Dessert, C., Lajeunesse, E., Crispi, O., Pastor, L., Gaillardet, J., and Benedetti, M. F.

Subjects
WATERSHEDS, OCEANOGRAPHY, METEOROLOGY, SOIL erosion, HYDRODYNAMICS, VOLCANISM
Abstract

In the tropic, the small watersheds are affected by intense meteorological events playing an important role on the erosion of soils and therefore on the associated organic carbon fluxes. We studied the geochemistry of three small watersheds around the Basse-Terre volcanic Island (FWI) during a four years period, by measuring DOC, POC and DIC concentrations. The mean annual yields ranged 8.1-15.8tCkm-2 yr -1, 1.9-8.6tCkm-2yr-1 and 8.1-25.5tCkm-2 yr-1 for DIC, DOC and POC, respectively. Floods and extreme floods represent 45 to 70 % of the annual DOC flux, and more than 80 % of the annual POC flux. The DIC flux occurs essentially during the low water level, only 43% of the annual DIC flux is exported during floods. The distribution of the dissolved carbon between the inorganic and the organic fraction is correlated to the hydrody-namic of rivers. During low water level and floods, the dissolved carbon is exported under the inorganic form (DIC/DOC = 2.6±2.1), while during extreme floods, the dissolved carbon transported is mostly organic (DIC/DOC = 0.7 ± 0.2). The residence time s of the organic carbon in Guadeloupean soils may vary from 381 to 1000yr, and is linked to the intensity of meteorological events than the frequency of meteorological events. Looking at the global carbon mass balance, the total export of organic carbon coming from small tropical and volcanic mountainous rivers is estimated about 2.0-8.9TgCyr-1 for DOC and about 8.4-26.5TgCyr-1 for POC, emphasizing that these carbon fluxes are significant and should be included in global carbon budgets. [ABSTRACT FROM AUTHOR]

Published
2012
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19. Effects of Phosphorus Limitation on the Bioavailability of DOM Released by Marine Heterotrophic Prokaryotes.

Author

Bouchachi N, Obernosterer I, Carpaneto Bastos C, Li F, Scenna L, Marie B, Crispi O, Catala P, and Ortega-Retuerta E

Subjects
Biological Availability, Bacteria, Mediterranean Sea, Dissolved Organic Matter, Phosphorus analysis
Abstract

Heterotrophic prokaryotes (HP) contribute largely to dissolved organic matter (DOM) processing in the ocean, but they also release diverse organic substances. The bioavailability of DOM released by HP under varying environmental conditions has not been fully elucidated. In this study, we investigated the bioavailability of DOM released by a single bacterial strain (Sphingopyxis alaskensis) and 2 natural HP communities grown under P-replete and P-limited conditions. The released DOM (HP-DOM) was used as a substrate for natural HP communities at a coastal site in the Northwestern Mediterranean Sea. We followed changes in HP growth, enzymatic activity, diversity, and community composition together with the consumption of HP-DOM fluorescence (FDOM). HP-DOM produced under P-replete and P-limited conditions promoted significant growth in all incubations. No clear differences in HP-DOM lability released under P-repletion and P-limitation were evidenced based on the HP growth, and P-limitation was not demonstrated to decrease HP-DOM lability. However, HP-DOM supported the growth of diverse HP communities, and P-driven differences in HP-DOM quality were selected for different indicator taxa in the degrading communities. The humic-like fluorescence, commonly considered recalcitrant, was consumed during the incubations when this peak was initially dominating the FDOM pool, and this consumption coincided with higher alkaline phosphatase activity. Taken together, our findings emphasize that HP-DOM lability is dependent on both DOM quality, which is shaped by P availability, and the composition of the consumer community., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Published
2023
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20. Trajectories of nutrients concentrations and ratios in the French coastal ecosystems: 20 years of changes in relation with large-scale and local drivers.

Author

Lheureux A, David V, Del Amo Y, Soudant D, Auby I, Bozec Y, Conan P, Ganthy F, Grégori G, Lefebvre A, Leynart A, Rimmelin-Maury P, Souchu P, Vantrepote V, Blondel C, Cariou T, Crispi O, Cordier MA, Crouvoisier M, Duquesne V, Ferreira S, Garcia N, Gouriou L, Grosteffan E, Le Merrer Y, Meteigner C, Retho M, Tournaire MP, and Savoye N

Subjects
Humans, Human Activities, Nutrients, Ecosystem, Climate Change
Abstract

Along with their important diversity, coastal ecosystems receive various amounts of nutrients, principally arising from the continent and from the related human activities (mainly industrial and agricultural activities). During the 20th century, nutrients loads have increased following the increase of both the global population and need of services. Alongside, climate change including temperature increase or atmospheric circulation change has occurred. These processes, Ecosystem state changes are hard to monitor and predict. To study the long-term changes of nutrients concentrations in coastal ecosystems, eleven French coastal ecosystems were studied over 20 years as they encompass large climatic and land pressures, representative of temperate ecosystems, over a rather small geographical area. Both univariate (time series decomposition) and multivariate (relationships between ecosystems and drivers) statistical analyses were used to determine ecosystem trajectories as well as typologies of ecosystem trajectories. It appeared that most of the French coastal ecosystems exhibited trajectories towards a decrease in nutrients concentrations. Differences in trajectories mainly depended on continental and human influences, as well as on climatic regimes. One single ecosystem exhibited very different trajectories, the Arcachon Bay with an increase in nutrients concentrations. Ecosystem trajectories based on ordination techniques were proven to be useful tools to monitor ecosystem changes. This study highlighted the importance of local environments and the need to couple uni- and multi-ecosystem studies. Although the studied ecosystems were influenced by both local and large-scale climate, by anthropogenic activities loads, and that their trajectories were mostly similar based on their continental influence, non-negligible variations resulted from their internal functioning., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Published
2023
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21. Organic Phosphorus Scavenging Supports Efficient Growth of Diazotrophic Cyanobacteria Under Phosphate Depletion.

Author

Rabouille S, Tournier L, Duhamel S, Claquin P, Crispi O, Talec A, Landolfi A, and Oschlies A

Abstract

Considering the reported significant diazotrophic activities in open-ocean regions where primary production is strongly limited by phosphate, we explored the ability of diazotrophs to use other sources of phosphorus to alleviate the phosphate depletion. We tested the actual efficiency of the open-ocean, N 2 -fixer Crocosphaera watsonii to grow on organic phosphorus as the sole P source, and observed how the P source affects the cellular C, N, and P composition. We obtained equivalent growth efficiencies on AMP and DL-α-glycerophosphate as compared with identical cultures grown on phosphate, and survival of the population on phytic acid. Our results show that Crocosphaera cannot use all phosphomonoesters with the same efficiency, but it can grow without phosphate, provided that usable DOP and sufficient light energy are available. Also, results point out that organic phosphorus uptake is not proportional to alkaline phosphatase activity, demonstrating that the latter is not a suitable proxy to estimate DOP-based growth yields of organisms, whether in culture experiments or in the natural environment. The growth parameters obtained, as a function of the P source, will be critical to improve and calibrate mathematical models of diazotrophic growth and the distribution of nitrogen fixation in the global ocean., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Rabouille, Tournier, Duhamel, Claquin, Crispi, Talec, Landolfi and Oschlies.)

Published
2022
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22. Dissolved organic matter released by two marine heterotrophic bacterial strains and its bioavailability for natural prokaryotic communities.

Author

Ortega-Retuerta E, Devresse Q, Caparros J, Marie B, Crispi O, Catala P, Joux F, and Obernosterer I

Subjects
Biological Availability, Photobacterium, Sphingomonadaceae metabolism
Abstract

Marine heterotrophic prokaryotes (HP) play a key role in organic matter processing in the ocean; however, the view of HP as dissolved organic matter (DOM) sources remains underexplored. In this study, we quantified and optically characterized the DOM produced by two single marine bacterial strains. We then tested the availability of these DOM sources to in situ Mediterranean Sea HP communities. Two bacterial strains were used: Photobacterium angustum (a copiotrophic gammaproteobacterium) and Sphingopyxis alaskensis (an oligotrophic alphaproteobacterium). When cultivated on glucose as the sole carbon source, the two strains released from 7% to 23% of initial glucose as bacterial derived DOM (B-DOM), the quality of which (as enrichment in humic or protein-like substances) differed between strains. B-DOM induced significant growth and carbon consumption of natural HP communities, suggesting that it was partly labile. However, B-DOM consistently promoted lower prokaryotic growth efficiencies than in situ DOM. In addition, B-DOM changed HP exoenzymatic activities, enhancing aminopeptidase activity when degrading P. angustum DOM, and alkaline phosphatase activity when using S. alaskensis DOM, and promoted differences in HP diversity and composition. DOM produced by HP affects in situ prokaryotic metabolism and diversity, thus changing the pathways for DOM cycling (e.g. respiration over biomass production) in the ocean., (© 2020 Society for Applied Microbiology and John Wiley & Sons Ltd.)

Published
2021
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23. Seasonal dynamics of prokaryotes and their associations with diatoms in the Southern Ocean as revealed by an autonomous sampler.

Author

Liu Y, Blain S, Crispi O, Rembauville M, and Obernosterer I

Subjects
Bacteria classification, Bacteria genetics, Bacteria isolation & purification, Carbon analysis, Diatoms classification, Diatoms growth & development, Eutrophication, Iron analysis, RNA, Ribosomal, 16S genetics, Seasons, Seawater chemistry, Diatoms microbiology, Microbiota physiology, Oceans and Seas, Seawater microbiology
Abstract

The Southern Ocean remains one of the least explored marine environments. The investigation of temporal microbial dynamics has thus far been hampered by the limited access to this remote ocean. We present here high-resolution seasonal observations of the prokaryotic community composition during phytoplankton blooms induced by natural iron fertilization. A total of 18 seawater samples were collected by a moored remote autonomous sampler over 4 months at 5-11 day intervals in offshore surface waters (central Kerguelen Plateau). Illumina sequencing of the 16S rRNA gene revealed that among the most abundant amplicon sequence variants, SAR92 and Aurantivirga were the first bloom responders, Pseudomonadaceae, Nitrincolaceae and Polaribacter had successive peaks during the spring bloom decline, and Amylibacter increased in relative abundance later in the season. SAR11 and SUP05 were abundant prior to and after the blooms. Using network analysis, we identified two groups of diatoms representative of the spring and summer bloom that had opposite correlation patterns with prokaryotic taxa. Our study provides the first seasonal picture of microbial community dynamics in the open Southern Ocean and thereby offers biological insights to the cycling of carbon and iron, and to an important puzzling issue that is the modest nitrate decrease associated to iron fertilization., (© 2020 Society for Applied Microbiology and John Wiley & Sons Ltd.)

Published
2020
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