NWAdriaticSeabiogeochemicalvariabilityinthelast20years (1986-2005)

Thispaperpresentsalong-termtimeseries(1986- 2005)ofhydrologicalandbiogeochemicaldata,bothpub- lishedandunpublished.Datawerecollectedinthenorth- westernareaoftheAdriaticSea,attwostationsthatare consideredhydrodynamicallyandtrophicallydifferent.The timeserieshavebeenstatisticallyandgraphicallyanalysed onamonthlyscaleinordertostudytheannualclimatolo- gies,linksbetweentheconcentrationsofchlorophyll-aand thevariabilityintheenvironment,trophicdifferencesbe- tweenthetwoareasandchlorophyll-atrendsovertime.Ba- sically,thetwoareashavesimilarhydrologicalfeatures,yet theypresentsignificantdifferencesintheamountofnutrient inputs:theseareinfacthigheratthecoastalsite,whichis characterizedbyaprevalenceofsurfaceblooms,whilethey arelowerattheoffshorestation,whichismainlyaffected bybloomsatintermediatedepths.Nonetheless,through- outthewholewatercolumn,chlorophyll-aconcentrations areonlyslightlydifferent.Bothareasareaffectedbyriver- inedischarge,thoughchlorophyll-aconcentrationsarealso drivenstronglybytheseasonalcycleatthestationcloserto thecoast.Resultsshowthatthetwostationsarenottroph- icallydifferent,althoughsomecontrollingfactors,suchas zooplanktongrazinginonecaseandlightattenuationinthe other,mayfurtherregulatethegrowthofphytoplankton.In bothcasesnosignificanttrendsaredetectedineithertheav- eragechlorophyll-avaluesorindispersionofthedata,in contrastwithsignificanttrendsintemperatureandsalinity.