LIFE OF THE BAYSA film lecure by Richard KernPresented at your school on: ___________

A Supplement for Teachers

Encounters in Excellence presents

sponsored by The Batchelor Foundation

Life of the Bays

Thefollowingsupplementwillclarifyandprovidedepth tosubjects focusedupon in“Lifeof theBays.” If thesematerialscanbetaughtintheclassroomafewdayspriortothestudentsseeingthefilm,thestudentswillgainmorefrom

thepresentation.

Introduction

In discussions of the major ecosystems ofSouth Florida, the Everglades steals much of thespotlight. However, Florida Bay, Biscayne Bayand theFlorida Keys are equally fascinating andequally important when considering the overallenvironmental health of our region. They facemany of the same problems including pollution, redirected water flowandexotic invasive speciesthatarecontributingtotheirdeterioration. In the movie LIFE OF THE BAYS therelationshipofthevarioushabitatsfoundinthebaysandkeyswillbeexplored.Attentionwillbegiventomanyofthefascinatinglife-formsthatresidethere,aswellas the impacthumanbeingshaveon theirfuture.

Habitats

1.Florida’sCORALREEFScanbefoundtotheeastandsouthoftheFloridaKeysjustbeyondtheseagrasscommunities.Tinyseaanimalscalledcoralpolypsbuildthesereefsbysecretingcalciumcarbonate,creatingstonyskeletonsoneupontheotherovermanyyears.Coralsareancient,thefirstknowncoralsappearingover500millionyearsago.WegetasenseofhowthegeologyandclimateoftheearthhasshiftedovertimewhenwerealizethatmostoftheFloridaKeysarebuiltuponexposed,ancientcoralreefs. Inandaroundthereefslivealargevarietyofbeautifultropicalfish,aswellascolorfulspongesandexoticsoft corals(seawhips,searodsandseafans,alsocalledgorgonians), sea anemones,marinewormsandahostofother interestingcreatures. Manyof thesecreatureshave,over time,adapteduniquelytothecomplexlandscapeofthereefinordertosurvive.Theballoonfish,forexamplehasadaptedthedefensiveabilitytoinflateitsbody,revealingdozensofspines.Thegreen moray eelisanambushpredatorthatlikestohideinthecrevassesofthecoralreefs.Ithasasecondsetofjawsinthebackofitsthroattopreventpreyfromescapingitsgrip. Inorder for coral reefs togrow, several environmental factorsareessential. Only inwarm,shallow,andclear,andfairlycalmwaterswillcoralsthrive.Therefore,thewatersofSouthFloridaaretheonlyplacesoffthecontinentalU.S.coastwherelivecoralreefsexist.(SC.7.E.6.4, SC.7.L.15.2)

2.TheSEAGRASScommunitybeginsjustbeyondtheshadowofthemangrovetreeswherethewater is shallowenough for sunlight topenetrateandcalmenough for thegrasses to stay rooted.Threespeciesofgrassesgrowhere:Cubanshoalgrass,manateegrass,andturtle grass-turtlegrassbeingbyfarthemostimportant. ThesebedsofmostlyturtlegrassareconsideredtobethemainnurserygroundsforfishandinvertebratesinAmericantropicalwater.Hereinthegrassbedsjuvenilefishgrowanddevelop.As

1.

adultstheyfindtheirhomelargelyonthecoralreefs.Long,flatgrassbladesprovidelotsofsurfaceareaforattachmentoffilamentousalgaeplusmanytiny invertebrates likehydroids, tunicates,andtubeworms.Hostsofminutemolluskscrawlontheblades,andsofoodsuppliesareplentifulforfish.Sincethegrassgrowsdensely,itprovidesgoodcoverfrompredatorstoo. Inadditiontoprovidingastructureforothermarinelifetogrowandflourish,seagrassesarealsoavaluablefoodsourceformanyimportantresidentsofthebay.Turtlegrassconstitutesthemaindietofthegreen sea turtle,the West Indian manateeandthevariegated sea urchin,whichconsumesmoreseagrassthaneithertheturtleorthemanatee. Animportantroleplayedbyseagrasscommunitiesnearcoralreefsistostrainoutsedimentdriftingtowardstheoceanandhelpkeepthewaterclear.Aswelearnedearlier,clearwaterisimportantforthegrowthofcorals.(SC.912.L.17.3)

3.TheMANGROVEFRINGE,linkinglandandwaterenvironments,consistsof4speciesoftrees.On the landsideare thebuttonwoodsandwhite mangroves. Closer to thewaterare theblack mangrovesandlastlythemostimportantspecies-thered mangrove-growsdirectlyinthesaltwater.Twocharacteristicsmakemangrovetreesuniquelysuitedforshorelinegrowth:theytoleratesaltandtheycansurvive,evenflourish,invariouslevelsoffloodingandtidalsurge. Mangrovesareimportantinstabilizingtheland.Theyalsohelptoblocktheflowofsaltwaterwhichhelpstocreateestuarieswhicharetransitionalzoneswherefreshwaterfromtheinlandmixeswithsaltwaterfromtheocean,importantfeedinggroundsformanyspeciesofwadingbirds.Mangrovesalsoprovideprotectionandnutritionformanyspeciesofyoungfish,shrimpandlobsters. Thecoralreefs,grassbedsandmangrovefringearelinkedtogetherinacomplexrelationshipthatsustainsallof the lifeof thebays. Mangrovesarethe linkbetweenlandandsea. Theirprop-rootscreateabuffer-zonethatprotectsthemainlandandthehardwoodhammocks(anotherimportantecosystemofthekeysandcoastalmainland)fromstormwinds.Theerosivepropertiesofwateraremonumental.Themangrovestakerootalongthecoastlineandalsohelptopreventcoastalerosioncausedbythepowerfultidesandcurrents. The leaf of the red mangrove is the base of the food web for the bay ecosystem. Themangrovesshedtheirleaves,whichfallintothewaterandarebrokendownbybacteriaandfungi.Theresultingwastematerialwashesoutwith thetidesandcurrents to theseagrassesandcoral reefs.Thenutrients fromthemangrove leavesareconsumedbyplanktonwhich in turn feedtinyfishandinvertebratesinthegrassbeds.(SC.6.E.6.1, SC.912.L.17.3, SC.912.L.17.9)

2.

Life Cycle of the Coral Polyp

CoralsbelongtotheanimalphylumCnidaria.Cnidarianshaveradialsymmetrywithsimplebodycavities,andtheyallhavestingingcellscallednematocysts.Hydroids,jellyfishandseaanemonesareotherexampleofcnidarians. Thereefbuildingcorals,sometimescalled“hardcorals”or“stonycorals,”createacup-shapedexternalskeletonwhichtheybuildbysecretingcalciumcarbonate.Thesoftbodyofthecoral,calledapolyp,canwithdrawitsmanytentaclesintothecupforprotection.Atnightthetentaclesareextendedtocatchplankton. Coralscanreproducesexuallyorasexually.Insexualreproductionspermarereleasedfromthemouthofthebodycavityintotheseawheretheymaydriftintothemouthofanotherpolyptofertilizetheeggsthere.Thisiscalled“broadcastspawning.”Later,thefertilizedeggleavesthroughthemouthofthepolypandbecomesafree-swimminglarvacalleda“planula.” After swimming for several weeks, the planula attachesitselftoahardsurface.Atfirstjustasmalldepressionformsontheunattachedend.Thentinytentaclesbegintopopuparoundthisdepressionwhichsoonbecomesthebodycavityofanadultpolyp. When the polyp is completely formed, it then beginssecretingitshardskeleton. There is an interesting relationship betweenmost coralvarietiesanda typeofalgacalledzooxanthellae. Thesingle-celledalgaeactuallylivewithinthetissueofthecoralpolyp.Thealgaeproducenutrients throughphotosynthesiswhich requireslight.Thisiswhyclear,shallowwaterisimportantforcoralgrowth.Thecoralsuseoxygengivenoffby thezooxanthellaeasaby-productofphotosynthesis. Thealgaealsohelp in thebuildingofthecoralskeletonandintransportingcertainnutrientswithinthecoralpolyp.Thisisanexampleofsymbioticmutualism,arelationshipinwhichbothorganismsbenefit.Zooxanthellaearealsousedbyotherformsofcnidarianlifesuchascertainvarietiesofseaanemonesandjellyfish,suchasthecassiopea,whichisalsocalledthe“upside-downjellyfish.” Coralsaredelicatecreatures,andthelandscapeofthereefcanshiftdramaticallywithchangesinclimate.Coral bleachingcanoccurwitharapidshiftinoceantemperatures.Theshockedpolypsexpelthezooxanthellaefromtheirtissues,whichusuallyresultsinthedeathofthepolyp.Oceanic acidification istheresultoftheriseofcarbondioxidelevels inthesea.Theoceansareimportantforabsorbingcarbonfromtheatmosphereandstoringit.Toomuchacidityinthewater,however,cancausetheexternalcalciumcarbonateskeletonsofthecoralpolypstodeteriorate. Itisworthnotingthatgorgonians(softcorals),althoughgrowingonandaddingmuchbeautytothereefs,differfromthestony,“reef-building”corals.Theyformflexibleskeletons,andtheirpolyptentacles

always number 8, with each tentacle often having tinybranches.Hardcoralshavesmoothtentacles,numbering6 or some multiple of 6, on each polyp. (SC.7.L.17.2, SC.912.L.17.4, SC912.E.7.9)

Life Cycle of the Red Mangrove

Fromthe tinyyellowflowerof theredmangrove treegrowsalong,thinpropagule.Thepropaguleisnotlikeatypicalfruit.Instead,itisactuallyayoungplantgrowingontheparenttree,sometimesforoverayear.Likemammals,

3.

mangrovesareviviparous,meaningtheyproduceliveembryonicyounginsteadofdormantseedslikemostplants. Whenthepropaguleisreadytofall,itcanbeasmuchas16incheslong.Whenitdoesfall,oftenitsinksintosoftmudnexttotheparenttreeandimmediatelybeginstogrow.Sometimes,however,thepropagulefloatsawayandiscarriedalongforasmuchasayearwiththecourseofthecurrents.Finally,oneendofthepropagulebecomeswaterloggedenoughtopull thepropaguleintoaverticalposition.Ifthewaterinthisnewlocationisshallowenoughandfreefrommuchturbulence,thenewmangrovewillsinkintothesoilbelow,sproutrootsandleaves,andbeginlife,sometimesveryfarfromwhereitsjourneybegan.(SC.912.L.17.3)

Some Facts on the American Crocodile

Although still listed as endangered,the American Crocodile has rebounded inrecent years. Theremay be close to 2000in South Florida now. They also live, butnot abundantly, in other locations aroundtheCaribbean, Central and SouthAmerica.Still,thecrocodileisfarout-numberedbyhiscloserelative,theAmericanAlligator,whoseFloridapopulationisestimatedtobeoveronemillion. Thenarrowerpointedsnoutisthemostobviousdifferencebetweenthecrocodileandthealligator.Thecolorationofthecrocodileisalsoslightlydifferent,showingbrownerandmoreolivehuescomparedtothegraysandblacksofthealligator. Crocodiles live in the brackish (saltmixedwith fresh)waters ofBiscayne andFloridaBays.AlligatorspreferthefreshwateroftheEverglades,riversandcanals. Disappearinghabitatisprobablythebiggestdangertothecrocodile’ssurvival;therefore,inspiteofrecentincreases,theirfutureisstilluncertain.Hypersalinityofthebaysisalsoastressfactor.Althoughcrocodileshavesaltglandsintheirmouthsforremovingsaltfromthewater,theycanstilldehydrateifthesaltconcentrationistoohigh.Youngcrocodilesareparticularlysusceptibletodehydration. American crocodilesareprimarily hole-nesters. Anaverageof 40 three-inch, oval eggsaredepositedinaholeduginthebeachsand.Approximatelytwomonthslaterthemotherhelpsthemhatchbydiggingthemoutandgentlycrackingtheeggsandcarryingthebabiestothenearbywaterjustasthealligatordoes.Itisestimatedthatonlyoneoutoffouroftheyoungthathatchwillsurvivetoadulthood. Interestingly,inrecentyearssuccessfulnestinghasoccurredintheprotectedcoolingcanalsoftheTurkeyPointNuclearPowerPlantinHomestead,Florida.Itisnowbelievedthat10%oftheannualviablehatchlingsarecomingfromtheTurkeyPointnests…arefreshingexampleofman’spotentialtoco-existwithnatureinapositiveway.(SC.912.L.17.12)

The Life of the Bays

AsresidentsofSouthFlorida,wehaveacloseconnectiontothewatersandlifeofourbays.Theoceanconnectsuswithmuchoftheworld.Itsupportsoureconomybyencouragingtrade,andtourism.We’refedbyitssea-life,andinspiredbyitsbeauty.Aswecontinuetopopulatethisarea,however,wearecompetingmoreandmoreforlandandresources.Asourappetitefortechnologyandmaterial

4.

5.

goodsrises,sodoesourneedforenergy.Muchofthisenergycomesfromburningfossilfuels,which

Answers to Quiz (last page)

1.b6.F2.a,c,d7.T3.b8.T4.d9.F5.c10.F

SuggestedWebsites:www.reefrelief.org

www.biscayne.national-park.com

spewscarbonintoouratmosphere.Wearebeginningtoseetheeffectsofcarbonandgreenhousegassesonourenvironment,climateandweatherpatterns. Algaeblooms(oftenduetopollutionandrunofffromthemainland)andturtlegrassdie-offsinbothbayshavebroughtaboutdramaticdecreases infish,shrimpand lobsterpopulations,ashaveover-fishing.Offthekeys,thedelicateandslowgrowingcoralreefsaresufferingconstantdamagefrombleaching,acidificationandotherstress-relateddiseases.Dragginganchorsandcarelessdiversalsodestroythecoralpolyps,andpropellerscarsfromspeedingboatshavecausedseriousdamagetotheseagrassbeds.Infact,mostoftheenvironmentalproblemsfacingourbayscanbedirectlyorindirectlyattributedtohumanpressure. Alongwith thekey deeroveradozenspeciesofplantsandanimals in thekeys’hammocksalonearethreatenedorendangeredduetothespreadofhumanpopulationandinfrastructure.ThesesamefactorshaveharmedthemangroveshorelinesandbeacheswheretheAmerican Crocodileandseveralsea turtlespeciesnowfightforsurvival.Inthewatersoffshorealovableseamammal,theWest Indian Manatee,hasmadesomesmallgainsbutstillhasalongstruggleahead.Heislarge,slow,andfrequentlysurfacesforairwhichmeansheispoorlyadaptedtothehundredsofboatsthatcrossourwaters.Manymanateesarestruckandkilledeachyear,theirgreatestthreat. All is not lost, however, and there are efforts tomitigate and hopefully reverse someof thedamagetothesedelicateecosystems.Artificialreefsprovidenewhomesforsealifewhileattractingrecreationaldivers,takingsomeofthepressureoffourcoralreefs.Also,experimentingwithmethodsto cultivate and transplant coral fragments and sea grassesmay lead to revitalization of our reefsandgrassbeds.Technologyhasthepossibilitytodevelopandutilizenew,cleanmethodsofenergyproduction,suchaswindandsolar. As individuals,wecan takesmall steps to reduceourcarbonfootprintandtoadvocateforresponsibleandsustainablewaystoliveinandenjoySouthFlorida,whileencouragingthehealthofourenvironmentandprotectingthelifeofthebays. (SC.7.E.6.6, SC.7.L.15.3, SC.912.L.17.15, SC.912.L.17.16, SC.912.L.17.17, SC.912.L.17.18, SC.912.E.6.6)

Quiz

Multiple choice

1.WhatisconsideredtobethebaseofthefoodwebforFloridaBayandBiscayneBay?(a)shrimplarvae(b)mangroveleaves(c)fisheggs(d)turtlegrass

2.Name3conditionsthatoceanenvironmentsmusthaveforcoralreefstogrowwell.(a)warmtemperatures(b)higherthanusualsalinity(saltiness)(c)shallowwater(d)clearwater(e)deepwater(f)fastcurrents

3.Newredmangrovetreesstartfrom….(a)seacucumbers(b)propagules(c)proproots(d)anemones(e)planula

4.Coralreefsaremadelargelyfrom….(a)tinyshellspressedtogetherovermanyyears(b)hugebouldersuponwhichmanyseaplantshavebeguntogrow(c)skeletonsofcoralshrimp(d)exoskeletonsoftinypolyps

5.Whichspeciesofanimalconsumesthemostturtlegrass?(a)WestIndianmanatee(b)lettuceseaslug(c)variegatedseaurchin(d)greenseaturtle

True or False

6.TheAmericanalligatorhasanarrower,morepointedsnoutthantheAmericancrocodile.____

7.Atypeofalgacalledzooxanthellaeliveswithinthetissuesofthecoralpolypinanimportantsymbioticrelationship.____

8.Coralreefsoftenprotectseagrassbedsfromdestructivestrongcurrents.____

9.Undertheproprootsofmangrovetreesonlytwospeciesoffishcansurvive.____

10.Wheremangrovetreesgrowalongashoreline,loosesedimenterodesaway,andtheshorelinerecedes.____

6.