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Auteur Meddeb, M.; Niquil, N.; Grami, B.; Mejri, K.; Haraldsson, M.; Chaalali, A.; Pringault, O.; Hlaili, A.S.
Titre (up) A new type of plankton food web functioning in coastal waters revealed by coupling Monte Carlo Markov chain linear inverse method and ecological network analysis Type Article scientifique
Année 2019 Publication Revue Abrégée Ecol. Indic.
Volume 104 Numéro Pages 67-85
Mots-Clés Bacterial multivorous food web; biogenic carbon; Coastal waters; continental-shelf; Ecology; ecosystem attributes; flow networks; Food web modeling; grazing impact; gulf; mediterranean sea; model analysis; Network analysis; Seasonal variations; seasonal-dynamics; trophic network; Trophic structure
Résumé Plankton food webs (PFW) typology is based on different categories of functioning, according to the dominant processes and the role played by heterotrophic bacteria, small vs large phytoplankton, and small vs large zooplankton. Investigating the structure and the function of planktonic food webs in two SW Mediterranean waters (inshore and marine sites) at four seasons, using inverse (LIM-MCMC) and ecological network (ENA) analyses, we identified a new type of food web, called the “bacterial multivorous food web”. This food web adds to the conventional trophic continuum as previously reported. The “bacterial multivorous food web” present in winter showed the lowest primary production among seasons, but highest bacterial production. Several food web ratios characterized this new typology e.g. picophytoplankton net primary production to total primary production varied from 0.20 to 0.28; bacterial to primary production ratio is higher than values reported in global scale (congruent to 1); bacterial net production to the potential protozoan prey net production was high (>0.2). In this special food web, carbon was mostly recycled, with a moderate fraction channeled to deep waters, which lead to a higher retention of carbon inside the ecosystem. This winter PFW also seemed to be the most organized, specialized, stable and mature, as related to common interpretations of ENA. The spring was characterized by herbivorous food web, with highest activity coinciding with low stability. Although less usual, the herbivorous pathway was also observed during summer, in inshore waters. The autumn food webs, which functioned as multivorous or microbial food webs, appeared to be stable and mature. Finally, our study demonstrates the usefulness of food web models derived ratios combined with ecological network analysis indices to conduct evaluation of the structure and functioning of ecosystems and potentially to support management decisions in marine environment.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1470-160x ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2596
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Auteur Olokotum, M.; Mitroi, V.; Troussellier, M.; Semyalo, R.; Bernard, C.; Montuelle, B.; Okello, W.; Quiblier, C.; Humbert, J.-F.
Titre (up) A review of the socioecological causes and consequences of cyanobacterial blooms in Lake Victoria Type Article scientifique
Année 2020 Publication Revue Abrégée Harmful Algae
Volume 96 Numéro Pages 101829
Mots-Clés climate-change; Consequences of cyanobacterial blooms; Cyanobacteria; East Africa; Eutrophication; harmful algal blooms; introduced nile perch; Lake Victoria; land-use; lates-niloticus; microcystin concentrations; murchison bay; nutrient concentrations; nyanza gulf; oreochromis-niloticus; Potential toxicity; Socioecological analysis
Résumé Africa is experiencing high annual population growth in its major river basins. This growth has resulted in significant land use change and pollution pressures on the freshwater ecosystems. Among them, the Lake Victoria basin, with more than 42 million people, is a unique and vital resource that provides food and drinking water in East Africa. However, Lake Victoria (LV) has experienced a progressive eutrophication and substantial changes in the fish community leading to recurrent proliferation of water hyacinth and cyanobacteria. Based on an extensive literature review, we show that cyanobacterial biomasses and microcystin concentrations are higher in the bays and gulfs (B&Gs) than in the open lake (OL), with Microcystis and Dolichospermum as the dominant genera. These differences between the B&Gs and the OL are due to differences in their hydrological conditions and in the origins, type and quantities of nutrients. Using data from the literature, we describe the multiple ways in which the human population growth in the LV watershed is connected to the increasing occurrence of cyanobacterial blooms in the OL and B&Gs. We also described the consequences of cyanobacterial blooms on food resources and fishing and on direct water use and water supply of local populations, with their potential consequences on the human health. Finally, we discuss the actions that have been taken for the protection of LV. Although many projects have been implemented in the past years in order to improve the management of waste waters or to reduce deforestation and erosion, the huge challenge of the reduction of cyanobacterial blooms in LV by the control of eutrophication seems far from being achieved.
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Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1568-9883 ISBN Médium
Région Expédition Conférence
Notes WOS:000541912700007 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2822
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Auteur van der Heide, T.; Govers, L.L.; de Fouw, J.; Olff, H.; van der Geest, M.; van Katwijk, M.M.; Piersma, T.; van de Koppel, J.; Silliman, B.R.; Smolders, A.J.P.; van Gils, J.A.
Titre (up) A three-stage symbiosis forms the foundation of seagrass ecosystems Type Article scientifique
Année 2012 Publication Revue Abrégée Science
Volume 336 Numéro Pages 1432-1434
Mots-Clés mutualistic networks zostera-marina biodiversity bivalves sulfide architecture diversity sediments bacteria mollusca
Résumé Seagrasses evolved from terrestrial plants into marine foundation species around 100 million years ago. Their ecological success, however, remains a mystery because natural organic matter accumulation within the beds should result in toxic sediment sulfide levels. Using a meta-analysis, a field study, and a laboratory experiment, we reveal how an ancient three-stage symbiosis between seagrass, lucinid bivalves, and their sulfide-oxidizing gill bacteria reduces sulfide stress for seagrasses. We found that the bivalve-sulfide-oxidizer symbiosis reduced sulfide levels and enhanced seagrass production as measured in biomass. In turn, the bivalves and their endosymbionts profit from organic matter accumulation and radial oxygen release from the seagrass roots. These findings elucidate the long-term success of seagrasses in warm waters and offer new prospects for seagrass ecosystem conservation.
Adresse [van der Heide, Tjisse; Olff, Han] Univ Groningen, CEES, Community & Conservat Ecol Grp, NL-9700 CC Groningen, Netherlands. [Govers, Laura L.; van Katwijk, Marieke M.] Radboud Univ Nijmegen, Dept Environm Sci, Inst Water & Wetland Res, Fac Sci, NL-6525 AJ Nijmegen, Netherlands. [de Fouw, Jimmy; van der Geest, Matthijs; Piersma, Theunis; van Gils, Jan A.] NIOZ Royal Netherlands Inst Sea Res, Dept Marine Ecol, NL-1790 AB Den Burg, Texel, Netherlands. [Piersma, Theunis] Univ Groningen, CEES, Anim Ecol Grp, NL-9700 CC Groningen, Netherlands. [van de Koppel, Johan] NIOZ Royal Netherlands Inst Sea Res, Ctr Estuarine & Marine Ecol, NL-4400 AC Yerseke, Netherlands. [Silliman, Brian R.] Univ Florida, Dept Biol, Gainesville, FL 32611 USA. [Smolders, Alfons J. P.] Radboud Univ Nijmegen, Inst Water & Wetland Res, Dept Aquat Ecol & Environm Biol, Fac Sci, NL-6525 AJ Nijmegen, Netherlands. van der Heide, T (reprint author), Univ Groningen, CEES, Community & Conservat Ecol Grp, POB 11103, NL-9700 CC Groningen, Netherlands t.van.der.heide@rug.nl
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Langue English Langue du Résumé Titre Original
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ISSN 0036-8075 ISBN Médium
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Notes ISI Document Delivery No.: 958BT Times Cited: 0 Cited Reference Count: 27 van der Heide, Tjisse Govers, Laura L. de Fouw, Jimmy Olff, Han van der Geest, Matthijs van Katwijk, Marieke M. Piersma, Theunis van de Koppel, Johan Silliman, Brian R. Smolders, Alfons J. P. van Gils, Jan A. “Waddenfonds” program; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)-WOTRO[W.01.65.221.00]; NWO-VIDI[864.09.002]; NSF; Andrew Mellon Foundation; Royal Netherlands Academy We thank G. Quaintenne and H. Blanchet for their help with the collection of Loripes; J. Eygensteyn and E. Pierson for technical assistance; and G. J. Vermeij, H. de Kroon, T. J. Bouma, E. J. Weerman, and C. Smit for their comments on the manuscript. T.v.d.H. was financially supported by the “Waddenfonds” program; M.v.d.G. and T.P. by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)-WOTRO Integrated Programme grant W.01.65.221.00 awarded to T.P.; and J.d.F. and J.v.G. by the NWO-VIDI grant 864.09.002 awarded to J.v.G. B.S. was supported by an NSF CAREER award, the Andrew Mellon Foundation, and the Royal Netherlands Academy Visiting Professorship. The authors declare no conflicts of interest. A detailed description of all materials and methods, sources, as well as supplementary information are available as supplementary materials. The data are deposited in DRYAD at http://dx.doi.org/10.5061/dryad.210mp. Amer assoc advancement science Washington Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ 734 collection 1381
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Auteur Roques, C.; Grousset, E.; Troussellier, M.; Hermet, S.; Le Carrer, J.; Sar, C.; Caro, A.
Titre (up) A trade-off between mucocytes and bacteriocytes inLoripes orbiculatusgills (Bivalvia, Lucinidae): a mixotrophic adaptation to seasonality and reproductive status in a symbiotic species? Type Article scientifique
Année 2020 Publication Revue Abrégée Mar. Biol.
Volume 167 Numéro 10 Pages 154
Mots-Clés bacterial endosymbionts; carbon; chemoautotrophic symbionts; codakia-orbicularis; crassostrea-virginica; life-cycle; loripes-lucinalis; lucinoma-aequizonata; mytilus-edulis; particle processing mechanisms
Résumé In this study, we investigated the composition of the gill tissue relative to the reproductive status of the lucinid clamLoripes orbiculatus(sensus Poli, 1791) according to seasonal as well as biological parameters to provide insights into the physiological variability of this symbiotic bivalve. Temporal variation in population density was also studied. The species was investigated inZostera noltiiseagrass beds in the Thau lagoon (43 degrees 26 ' 52.27 '' N, 3 degrees 39 ' 6.25 '' E) in the south of France in a monthly sampling study from May 2013 to July 2015. A total of 257 individual adults of different sizes were analysed according to water temperature and salinity variations. The findings revealed a very stableLoripesdensity over time, with one single reproductive period during late spring/early summer. We also found that bacteriocytes and mucocytes in the gills were negatively correlated and highly variable in their respective proportions. Bacteriocytes remained dominant during cold periods, whereas mucocytes appeared mainly in the gills of large individuals when the water temperature increased in the spring. As mucocytes were also related with gonadal maturation, we hypothesize that these may allow the host to increase the proportion of heterotrophy in its nutrition during spring primary production to face the metabolic demands required for reproduction. It is possible that mucocytes may also be involved in host immunity.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0025-3162 ISBN Médium
Région Expédition Conférence
Notes WOS:000576898400001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2895
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Auteur Fouilland, E.; Tolosa, I.; Bonnet, D.; Bouvier, C.; Bouvier, T.; Bouvy, M.; Got, P.; Le Floc'h, E.; Mostajir, B.; Roques, C.; Sempéré, R.; Sime-Ngando, T.; Vidussi, F.
Titre (up) Bacterial carbon dependence on freshly produced phytoplankton exudates under different nutrient availability and grazing pressure conditions in coastal marine waters Type Article scientifique
Année 2014 Publication Revue Abrégée FEMS microbiology ecology
Volume 87 Numéro 3 Pages 757-769
Mots-Clés bacteria; carbon coupling; coastal waters; interactions; phytoplankton
Résumé The effects of grazing pressure and inorganic nutrient availability on the direct carbon transfer from freshly produced phytoplankton exudates to heterotrophic bacteria biomass production were studied in Mediterranean coastal waters. The short-term incorporation of (1)(3)C (H(1)(3)CO(3)) in phytoplankton and bacterial lipid biomarkers was measured as well as the total bacterial carbon production (BP), viral lysis and the microbial community structure under three experimental conditions: (1) High inorganic Nutrient and High Grazing (HN + HG), (2) High inorganic Nutrient and Low Grazing (HN + LG) and (3) under natural in situ conditions with Low inorganic Nutrient and High Grazing (LN + HG) during spring. Under phytoplankton bloom conditions (HN + LG), the bacterial use of freshly produced phytoplankton exudates as a source of carbon, estimated from (1)(3)C enrichment of bacterial lipids, contributed more than half of the total bacterial production. However, under conditions of high grazing pressure on phytoplankton with or without the addition of inorganic nutrients (HN + HG and LN + HG), the (1)(3)C enrichment of bacterial lipids was low compared with the high total bacterial production. BP therefore seems to depend mainly on freshly produced phytoplankton exudates during the early phase of phytoplankton bloom period. However, BP seems mainly relying on recycled carbon from viral lysis and predators under high grazing pressure.
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Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1574-6941 ISBN Médium
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Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 444
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