19 research outputs found
Twenty years of satellite and in situ observations of surface chlorophyll-a from the northern Bay of Biscay to the eastern English Channel. Is the water quality improving?
Get PDFThevariabilityofthephytoplanktonbiomassderivedfromdailychlorophyll-a(Chl-a)satelliteimageswasinvestigated over the period 1998â2017 in the surface waters of the English Channel and the northern Bay of Biscay. Merged satellite (SeaWiFS-MODIS/Aqua-MERIS-VIIRS) Chl-a wascalculated using the OC5 Ifremeralgorithm which is optimized for moderately-turbid waters. The seasonal cycle in satellite-derived Chl-a was comparedwithinsitumeasurementsmadeatsevencoastalstationslocatedinthesouthernsideoftheEnglish ChannelandinthenorthernBayofBiscay.TheresultsfirstlyshowedthatthesatelliteChl-aproduct,derived from a suite of space-borne marine reflectance data, is in agreement with the coastal observations. For compliancewiththedirectivesoftheEuropeanUniononwaterquality,time-seriesof6-yearmovingaverageofChlawereassessedovertheregion.Acleardeclinewasobservedinthemeanand90thpercentileofChl-aatstations locatedinthemixedwatersoftheEnglishChannel.Thetime-seriesatthestationslocatedintheBayofBiscay showedyearlyfluctuationswhichcorrelatedwellwithriverdischarge,butnooverallChl-atrendwasobserved. IntheEnglishChannel,theshapeoftheseasonalcycleinChl-achangedovertime.Narrowerpeakswereobservedinspringattheendofthestudiedperiod,indicatinganearlierlimitationbynutrients.Monthlyaverages of satellite Chl-a, over theperiods 1998â2003and2012â2017,exhibitedspatial andtemporalpatternsin the evolutionofthephytoplanktonbiomasssimilartotheseobservedatthesevencoastalstations.Boththeinsitu andsatelliteChl-atimes-seriesshowedadecreaseinChl-aintheEnglishChannelinMay,JuneandJuly.This trendinphytoplanktonbiomassiscorrelatedwithlowerriverdischargesattheendoftheperiodandaconstant reduction in the riverine input of phosphorus through improvements in the water quality of the surrounding rivercatchments
Seasonal variability of living benthic foraminifera from the outer continental shelf of the Bay of Biscay
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Occurrence and seasonality of Vibrio aestuarianus in sediment and Crassostrea gigas haemolymph at two oyster farms in France
No full textImpact of Oyster Farming on Diagenetic Processes and the Phosphorus Cycle in Two Estuaries (Brittany, France)
No full textPhosphorus dynamics and bioavailability in sediments of the Penzé Estuary (NW France): in relation to annual P-fluxes and occurrences of Alexandrium Minutum
No full textStrong gradient of benthic biogeochemical processes along a macrotidal temperate estuary: focus on P and Si cycles
No full textSpatial and Temporal Variability of Sediment Organic Matter Recycling in Two Temperate Eutrophicated Estuaries
No full textPhosphorus speciation in the marine sediment of Kalpakkam coast, southeast coast of India
No full textPhosphorus content and fractionation of phosphate in the surface sediments of the Daliao river system in China
No full textPhosphorus adsorption and release characteristics of surface sediments in Dianchi Lake, China
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