@article {6869, title = {Fatty acids, C and N dynamics and stable isotope ratios during experimental degradation of shrimp pond effluents in mangrove water}, journal = {Marine Environmental Research}, volume = {150}, year = {2019}, month = {Jan-09-2019}, pages = {104751}, issn = {01411136}, doi = {10.1016/j.marenvres.2019.104751}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0141113619301953}, author = {Vivier, Baptiste and Frank David and Cyril Marchand and Thanh-Nho, Nguyen and Tarik Meziane} } @article {5984, title = {Short-term changes in the quality of suspended particulate matter in a human impacted and mangrove dominated tropical estuary (Can Gio, Vietnam)}, journal = {Continental Shelf Research }, volume = {178}, year = {2019}, month = {01/05/2019}, pages = {59-67}, abstract = {

Suspended particulate matter (SPM) is a key component of coastal food webs and a key variable of nutrient budgets. Understanding its variability across short time scales in estuaries may help ecologists understand seasonal and diurnal migration of estuarine organisms, and answer how their nutritional requirements are fulfilled. It may also inform biogeochemists regarding the factors that influence import and export of nutrients between terrestrial and coastal ecosystems. This study aimed to link the dynamics of fatty acids, stable isotopes (δ13C and δ15N) and C/N ratios of SPM, revealing organic matter quality, to rapidly varying factors (SPM concentration, salinity and presence of daylight) and comparing this variability to the seasonal variation induced by the alternation of dry and wet seasons in the studied region. Our results revealed that these rapidly varying factors had a strong influence on the bacterial and the phytoplanktonic compartments of SPM. They suggest that tidally resuspended particles are the site of intense heterotrophic activity and that estuarine phytoplankton store lipids during the daytime up to substantially modifying SPM quality. Our study also shows higher freshness of SPM during the wet season. We expect this study to raise the interest of both biologists and biogeochemists to introduce daily variability of SPM in food webs and nutrient budgets modelling.

}, doi = {10.1016/j.csr.2019.03.011}, author = {Frank David and Cyril Marchand and Najet Thiney and Tran-thi, N and Tarik Meziane} } @article {5769, title = {Trophic relationships and basal resource utilisation in the Can Gio Mangrove Biosphere Reserve (Southern Vietnam)}, journal = {Journal of Sea Research}, year = {2019}, abstract = {

Abstract Fatty acid biomarkers and dual stable isotopes (δ13C and δ15N) were used to identify the preferred food sources of consumers in a mangrove tidal creek and nearby unforested (mud bank) and forested areas located in the Can Gio Mangrove Biosphere Reserve (Southern Vietnam). We analysed 15 macro-invertebrates and 1 fish species representing primary consumers and their immediate predators in this area. Specific groups of fatty acids were used to trace the fate of various food sources (i.e., suspended particulate organic matter, mangrove litter and sedimentary organic matter). The δ13C and δ15N of consumers ranged from -26.9 to -18.8{\textperthousand} and from 1.1 to 9.9{\textperthousand}, respectively. The trophic pathway based on mangrove litter, characteristic of mangrove ecosystems, is nutritionally sustaining various crab and snail species. In contrast, it appears that the most mobile species (fish and shrimps), living in the water column and possibly migrating with tides, are mostly feeding on suspended particulate organic matter, suggesting that this trophic pathway is of great importance for connectivity among tropical coastal ecosystems. Our study suggests that snails and crabs mainly act as mineralisers, processing high quantities of detrital material to meet their nutritional needs and thus releasing nutrients through the production of faeces, that are further mineralised by microorganisms, while locally grown phytoplankton reintegrates these compounds into its biomass and feeds migrating species. We highlight here a possible link between mangrove litter and coastal food webs.

}, doi = {10.1016/j.seares.2018.12.006}, url = {https://www.sciencedirect.com/science/article/pii/S1385110118301679}, author = {Frank David and Cyril Marchand and Nguyen, Thanh-Nho and Pierre Taillardat and Tarik Meziane} } @article {5465, title = {Carbon biogeochemistry and CO2 emissions in a human impacted and mangrove dominated tropical estuary (Can Gio, Vietnam)}, journal = {Biogeochemistry}, year = {2018}, month = {27/04/2018}, pages = {1-15}, abstract = {

The quantitative contribution of tropical estuaries to the atmospheric CO2\ budget has large uncertainties, both spatially and seasonally. We investigated the seasonal and spatial variations of carbon biogeochemistry downstream of Ho Chi Minh City (Southern Vietnam). We sampled four sites distributed from downstream of a highly urbanised watershed through mangroves to the South China Sea coast during the dry and wet seasons. Measured partial pressure of CO2(pCO2) ranged from 660 to 3000\ μatm during the dry season, and from 740 to 5000\ μatm during the wet season. High organic load, dissolved oxygen saturation down to 17\%, and pCO2up to 5000\ μatm at the freshwater endmember of the estuary reflected the intense human pressure on this ecosystem. We show that releases from mangrove soils affect the water column pCO2\ in this large tropical estuary (~600\ m wide and 10{\textendash}20\ m deep). This study is among the few to report direct measurements of both water pCO2\ and CO2\ emissions in a Southeast Asian tropical estuary located in a highly urbanised watershed. It shows that the contribution of such estuaries may have been previously underestimated, with CO2\ emissions ranging from 74 to 876\ mmol\ m-2\ day-1\ at low current velocity (\<\ 0.2\ m\ s-1). Corresponding gas transfer velocities k600,\ ranging from 1.7 to 11.0\ m\ day-1,\ were about 2 to 4 times of k600\ estimated using published literature equations.

}, doi = {https://doi.org/10.1007/s10533-018-0444-z}, author = {Frank David and Tarik Meziane and Tran-thi, N and Truong Van, V and Th{\`a}nh-Nho, N and Pierre Taillardat and Cyril Marchand} } @article {5310, title = {Nutritional composition of suspended particulate matter in a tropical mangrove creek during a tidal cycle (Can Gio, Vietnam)}, journal = {Estuarine, Coastal and Shelf Science}, volume = {200}, year = {2018}, pages = {126-130}, doi = {10.1016/j.ecss.2017.10.017}, url = {https://doi.org/10.1016/j.ecss.2017.10.017}, author = {Frank David and Cyril Marchand and Pierre Taillardat and Th{\`a}nh-Nho, N and Tarik Meziane} } @article {4396, title = {Meiofauna distribution in a mangrove forest exposed to shrimp farm effluents (New Caledonia)}, journal = {Marine Environmental Research}, volume = {119}, year = {2016}, pages = {100 - 113}, abstract = {

Abstract Meiofauna abundance, biomass and individual size were studied in mangrove sediments subjected to shrimp farm effluents in New Caledonia. Two strategies were developed: i) meiofauna examination during the active (AP) and the non-active (NAP) periods of the farm in five mangrove stands characteristics of the mangrove zonation along this coastline, ii) meiofauna examination every two months during one year in the stand the closest to the pond (i.e. Avicennia marina). Thirteen taxonomic groups of meiofauna were identified, with nematodes and copepods being the most abundant ones. Meiofauna abundance and biomass increased from the land side to the sea side of the mangrove probably as a result of the increased length of tidal immersion. Abundance of total meiofauna was not significantly different before and after the rearing period. However, the effluent-receiving mangrove presented twice the meiofauna abundance and biomass than the control one. Among rare taxa, mites appeared extremely sensitive to this perturbation.

}, keywords = {New Caledonia}, issn = {0141-1136}, doi = {http://dx.doi.org/10.1016/j.marenvres.2016.05.028}, url = {http://www.sciencedirect.com/science/article/pii/S0141113616300976}, author = {L. Della Patrona and Cyril Marchand and C{\'e}dric Hubas and Nathalie Molnar and J. Deborde and Tarik Meziane} } @article {3559, title = {Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia)}, journal = {J. Mar. Sci. Eng.}, year = {2015}, month = {02/2015}, pages = {52-57}, type = {OPEN ACCESS}, abstract = {

In mangrove ecosystems, strong reciprocal interactions exist between plant and substrate. Under semi-arid climate, Rhizophora spp. are usually predominant, colonizing the seashore, and Avicennia marina develops at the edge of salt-flats, which is the highest zone in the intertidal range. Along this zonation, distribution and speciation of C, Fe, S, N, and P in sediments and pore-waters were investigated. From the land-side to the sea-side of the mangrove, sediments were characterized by I/ increase in: (i) water content; (ii) TOC; (iii) mangrove-derived OM; II/ and decrease in: (i) salinity; (ii) redox; (iii) pH; (iv) solid Fe and solid P. Beneath Avicennia and Rhizophora, TS accumulated at depth, probably as a result of reduction of iron oxides and sulfate. The loss of total Fe observed towards the sea-side may be related to sulfur oxidation and to more intense tidal flushing of dissolved components. Except the organic forms, dissolved N and P concentrations were very low beneath Avicennia and Rhizophora stands, probably as a result of their uptake by the root systems. However, in the unvegetated salt-flat, NH4+ can accumulate in organic rich and anoxic layers. This study shows: (i) the evolution of mangrove sediment biogeochemistry along the intertidal zone as a result of the different duration of tidal inundation and organic enrichment; and (ii) the strong links between the distribution and speciation of the different elements.

}, keywords = {biogeochemistry, Mangrove, New Caledonia, zonation}, issn = {2077-1312}, author = {Jonhatan Deborde and Cyril Marchand and Nathalie Molnar and Luc Della-Patrona and Tarik Meziane} } @article {3663, title = {Foraminiferal assemblages as bioindicators to assess potential pollution in mangroves used as a natural biofilter for shrimp farm effluents (New Caledonia)}, journal = {Marine Pollution Bulletin}, volume = {93}, year = {2015}, month = {15 April 2015}, pages = {103-120}, type = {Research}, abstract = {

In New Caledonia, semi-intensive shrimp farms release untreated effluents into the mangrove. Foraminiferal assemblages were analyzed for assessing the impact of effluent release on the benthic compartment. Comparison was made between samples collected (1) in an effluent receiving mangrove before and after the rearing cycle, and (2) for one-year monitoring an effluent receiving and a control mangrove. The distribution of foraminiferal assemblages was primarily driven by the gradient between\ Rhizophora\ stands and salt-flats, related to salinity and tidal elevation, and by seasonal cycles. The potential impact of effluent release was due to the combined effects of normal-saline effluents on surface salinity, and of nutrient input and microbial stimulation on food availability. Foraminiferal assemblages did not indicate a substantial impact of farm effluents and suggest that semi-intensive shrimp farming using mangrove for effluent discharge may appear as a sustainable solution in New Caledonia, when considering only the impact on the mangrove itself.

}, keywords = {Effluents, fatty acids, Foraminifera, Mangrove, Shrimp farming, SW Pacific}, doi = {10.1016/j.marpolbul.2015.02.009}, author = {Debenay, J-P and Cyril Marchand and Nathalie Molnar and Ad{\'e}laide Aschenbroich and Tarik Meziane} } @article {3522, title = {Spatio-temporal variations in the composition of organic matter in surface sediments of a mangrove receiving shrimp farm effluents (New Caledonia)}, journal = {Science of The Total Environment}, volume = {512{\textendash}513}, year = {2015}, pages = {296 - 307}, abstract = {

In order to investigate spatio-temporal variations in the composition and origin of the benthic organic matter (OM) at the sediment surface in mangrove receiving shrimp farm effluents, fatty acid (FA) biomarkers, natural stable isotopes (δ13C and δ15N), C:N ratios and chlorophyll-a (chl-a) concentrations were determined during the active and the non-active period of the farm. Fatty acid compositions in surface sediments within the mangrove forest indicated that organic matter inputs varied along the year as a result of farm activity. Effluents were the source of fresh particulate organic matter for the mangrove, as evidenced by the unsaturated fatty acid (UFA) distribution. The anthropogenic \{MUFA\} 18:1ω9 was not only accumulated at the sediment surface in some parts of the mangrove, but was also exported to the seafront. Direct release of bacteria and enhanced in situ production of fungi, as revealed by specific FAs, stimulated mangrove litter decomposition under effluent runoff condition. Also, microalgae released from ponds contributed to maintain high benthic chl-a concentrations in mangrove sediments in winter and to a shift in microphytobenthic community assemblage. Primary production was high whether the farm released effluent or not which questioned the temporary effect of shrimp farm effluent on benthic microalgae dynamic. This study outlined that mangrove benthic organic matter was qualitatively and quantitatively affected by shrimp farm effluent release and that responses to environmental condition changes likely depended on mangrove stand characteristics.

}, keywords = {Chlorophyll-a, fatty acids, Mangrove, Organic matter, Shrimp farming, Stable isotopes}, issn = {0048-9697}, doi = {http://dx.doi.org/10.1016/j.scitotenv.2014.12.082}, url = {http://www.sciencedirect.com/science/article/pii/S0048969714017938}, author = {Ad{\'e}laide Aschenbroich and Cyril Marchand and Nathalie Molnar and Jonhatan Deborde and C{\'e}dric Hubas and Herv{\'e} Rybarczyk and Tarik Meziane} } @article {3994, title = {Seasonal Pattern of the Biogeochemical Properties of Mangrove Sediments Receiving Shrimp Farm Effluents (New Caledonia)}, journal = {Journal of acquaculture research \& development}, volume = {05}, year = {2014}, issn = { 2155-9546}, author = {Cyril Marchand and Molnar, N and Deborde, J and Patrona, LC and Tarik Meziane} }