珊瑚与虫黄藻

CoralReefScience

StrategyforEcosystemSymbiosisandCoexistencewithHumansunderMultipleStresses

珊瑚与虫黄藻第1页Fig.1Multiplescalesofsymbioticsystemamongcoral-algalsymbionts,coralreefsandhumansFig.2Degradationofthecoralreefsymbioticsystembyglobalandlocalhumanstressors珊瑚与虫黄藻第2页Fig.3Coral-reefscenesinthemid-1970s.AsquotedinJackson(),SylviaEarlenotedin1972that“...tropicalreefs,notablefortheirdazzlingprofusionofanimallife,arealmostdevoidofconspicuousplants”.Brunoetal.()foundthatinnaturalundisturbedbaselineconditions,benthicalgaeispatchilydistributedandcanoccupyupto10–30%ofthesubstratum,averaging22%.Clockwisefromupperleft:UcubsuiReef,SanBlasIslands,CaribbeanPanama;IslasSecas,PacificPanama;ArekabesanIsland,Palau;Aunu’uIsland,AmericanSamoa;alsoAunu’u.Thesearenotarandomselectionofphotographs,butwereselectedtoshowhoweasyitwastobeimpressedwiththeprevalenceofanimaltissueinthe1970s.OdumandOdum(1955)arguedthatmany,ifnotmost,ofthealgaewereendolithicandoutofsight珊瑚与虫黄藻第3页Fig.4ACaribbeanboringsponge(Clionacfcaribbea)coveringanderodingseveralsquaremetersofreefsubstrate,SanBlas,Panama,3mdepth(30June1993).Arrowsdenoteperimeterofspongepatch珊瑚与虫黄藻第4页Fig.5

Reproductivemodesofscleractiniancorals.Upper:spawningcoralreleasingegg–spermbundles.Lower:broodingcoralreleasingplanulalarva(IllustrationbyDwiHaryanti)Fig.8

AphotoshowingdifferentialbleachingsusceptibilityofadjacentcoloniesofPoritesrandalliintheOfubackreefinAmericanSamoa.Bleachingiscommonlypatchyacrossareefandbleachedandunbleachedcoloniesareoftenobservedincloseproximity.WhetherthisvariabilityiscausedbyadaptationoracclimatizationofthehostorSymbiodiniumremainstobedetermined珊瑚与虫黄藻第5页Fig.6Typesofzooxanthellaeobservedincoraltissue.

(a,b)Healthycellswithasphericalshapeandexpandedchloroplast.(c,d)Shrunken,darklycoloredcellswithreducedsizesandpartiallyfragmentedchloroplasts.(e)Bleachedcellswithpaleandcolorlesschloroplasts.(f)Threecategoriesofzooxanthellae.(g)Whitelightmicrographand(h)fluorescenceimageofhealthyandshrunkencells(shrunkencellsareindicatedbyarrowheads)珊瑚与虫黄藻第6页Fig.7Newconceptofcoralbleachingrevealedfromcountingandobservationofzooxanthellae珊瑚与虫黄藻第7页Fig.8High-throughputRNAsequencingisincreasinglyusedasatooltounderstandthephysiologicalresponseofcoralstostressors.Libroetal.(,abovefromFigs.1and2)investigatedtheimmuneresponseofAcroporacervicornistoWhite-BandDisease(upperphoto)bycomparingRNA-seqprofilesofhealthyandinfectedtissues.Theirapproachidentifiedaseriesup-anddown-regulatedgenesthatrepre-sent4%ofthecoraltranscriptome(plottedinredbelow)Fig.9Molecularanalyseshavehadaprofoundimpactonourunderstandingofevolutionaryrelationshipsofmanycoralreeforganisms,includingcorals.Kitaharaetal.(,treeabovefromFig.1),inarecentcomprehensivephylogeneticanalysisofscleractiniancorals,showedthatdeep-seaazooxanthellatespeciesarebasaltothegroupandmostrecognizedshallow-waterzooxanthellatefamiliesarepolyphyletic.Insomecases,AtlanticandPacificspeciesoncethoughttobelongtothesamegenus,arenowplacedindifferentfamilies,suchasHomophyl