GEO-03\INT-10 The geochemical and biological study of corals
 
 
 
Poster
Predicting the future of scleractinian corals under the influence of expected climate changes (pCO2 and temperature)
Tuesday 10th @ 1610-1730 , Conference Room 4
S-GEO-03\INT-10-01
Mohamed belasy ismail* , Department of zoology, Faculty of Science, Al Azher University, Egypt
Presenter Email: Mohamed_belasy1989@yahoo.com

Climatechangese.g.oceanacidificationandwarmingcausedbyanthropogenicemissionofCO2arethegreatestglobalthreattocoralreefecosystems.ThechangeintheseawatercarbonatechemistryduetoOAisalarmingbecauseitspotentialaffectstheabilityoftropicalreef-buildingcoralsandothermarineorganismstoform(CaCO3)skeletons.DatashowthatadecreaseinpHfromcurrent(8.2units)toend-of-centuryprojectedlevels(7.7-7.8units)resultsina20-40%declineincoralcalcificationandanincreaseinthedissolutionrateofcarbonateskeleton,duetothesaturationstatusofCaCO3inseawaternegativelyaffectedbychangesinseasurfacetemperatureand/orCO2concentration.Reducedcoralgrowth,combinedwithweakercoralskeletonsandreefsubstrata,willincreasetheprobabilityofdamagetostructurallycomplexcoralsduringextremeweatherevents,leadingtoalossofreefstructurecomplexity,severelyreductionincoralsresilienceandrapiddeclinesinreefecosystembiodiversity.Therefore,thepotentialcapacityofscleractiniancoralsforacclimatizationoradaptationtooceanacidification(OA)anditsassociatedwarmingisakeyfactordeterminingtheirresiliencetofutureclimatechange.Reef-buildingcoralsareinhabitedbyfunctionallydiversemicroorganisms,whichplayvitalrolesinmaintainingholobionthealthandecosystemresilienceunderAnthropocene.Changesincoralmicrobiomecompositionisapotentialmechanismthatmayassistcoralstothriveunderstressfulconditions.Forinstance,thenorthernRedSeacoralsinhabitunderextremetemperaturesanomalies,withoutanybleachingsigns,suggestingthattheymayhaveselectiveandendemicmicrobiomesdonatethemthisuniquetolerability.SingleeffectofOAhadnosignificantinfluenceonbothSymbiodiniaceae&prokaryotic,whilethesynergisticeffectofOAandwarmingexacerbatethebleachingofcoralholobionts.Atthisstage,thereisnoclearconsensusaboutthephysiologicalandmoleculartraitsthatunderliecoraltolerancetoOAand/orwarming,consequently,reliableprojectionsoftheeffectsofclimatechangeonreefecosystemscannotbemade.Sothecurrentstudyaimstounderstandwhetherandhowcoralsacclimatizationoradapttolong-termofOAand/orwarming.WeassumethatthetolerabilityofcoralscorrelatedtoSymbiodiniummetabolismandthestabilityofitsassociatedmicrobiome