M EJI O RTI G ERMA EZ M ARILU PEZ M EJI 13 AND STEBAN ARZA G ONZA LEZ Abstract Cozumel Island is a Caribbean locale having karst as the main component of i ts surface Known caves are steepsided waterfilled sinkholes cenotes and almost all of them a ID: 15820
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A CKNOWLEDGEMENTS ThisworkwassupportedbythePROMEP-SEPPro- gramwithagranttotheproject,Loscrusta ´ceos cavern ´ colasdelaIsladeCozumel,andbytheUniversity ofQuintanaRooCampusCozumel.Theauthorsare gratefultoA.Antonio,A.Mun oz,L.May,andG.Mena, studentsfromtheundergraduateprogramofManejode RecursosNaturalesUQROOCozumel,fortheirassis- tanceduringthefieldwork,andtoO.Frausto-Mart ´ nezfor providingtheaerialphotographs.Theauthorsaregrateful toG.W.Mooreandananonymousreviewerforcriticisms andsuggestionstoimprovethispaper. R EFERENCES Bowman,T.E.,1987, Bahalanamayana ,anewtroglobiticcirolanid isopodfromCozumelIslandandtheYucatanPeninsula,Mexico, in BiologicalSocietyofWashingtonProceedings,v.100,p.659 663. Gaona-Vizcayno,S.,GordillodeAnda,T.,andVillasuso-Pino,M.,1980, Cenotes,karstcaracter ´ stico:Mecanismodeformacio ´n:Institutode Geolog ´ aRevista,v.4,p.3236. Hall,F.G.,1936,PhysicalandchemicalsurveyofcenotesofYucata ´n: CarnegieInstitutionofWashingtonPublication457,p.516. Hobbs,Jr.,H.H.,Hobbs,III.,H.H.,andDaniel,M.A.,1977,Areviewof thetroglobiticdecapodcrustaceansoftheAmericas:Smithsonian ContributionstoZoology244,p.1154. Holsinger,J.R.,1992,Twonewspeciesofthesubterraneanamphipod Bahadzia (Hadziidae)fromtheYucata ´nPen ´ nsularegionofsouthern Mexico,withananalysisofphylogenyandbiogeographyofthegenus: Stygologia,v.7,p.85102. Illife,T.M.,1992,Anannotatedlistofthetroglobiticanchialineand freshwaterfaunaofQuintanaRoo, in Navarro,D.,andSua ´rez-Morales, E.,eds.,Diversidadbiolo ´gicaenlaReservadelaBiosferadeSianKaan, QuintanaRoo,Me ´xico,ChetumalCIQRO/Sedesol,v.3,p.197217. Illife,T.M.,1993,Faunatroglobiaacua ´ticadelaPen ´ nsuladeYucata ´n, p.673686, in Salazar-Vallejo,S.I.,andGonza ´lez,N.E.,eds.,Biodiver- sidadmarinaycosteradeMe ´xico,CONABIOyCICROMe ´xico,867p. Kensley,B.,1988,Newspeciesandrecordsofcaveshrimpsfromthe YucatanPeninsula(Decapoda:AgostocarididaeandHippolytidae): JournalofCrustaceanBiology,v.8,p.688699. Milhollin,R.D.,1996,ArtifactsfromChuu-haCenote,Cozumel,Mexico: UnderwaterSpeleology,v.23,p.3031. Mej ´ a-Ort ´ z,L.M.,Yan ez,G.,andLo ´pez-Mej ´ a,M.,2006,Faunaoffive anchialinecavesinCozumelIsland,Me ´xico:NationalAssociationfor CaveDivingJournal,v.39,no.1,p.1115. Mej ´ a-Ort ´ z,L.M.,Yan ez,G.,andLo ´pez-Mej ´ a,M.,inpress,Echino- dermsinananchialinecaveinMexico:MarineEcology. Reddell,J.R.,1977,ApreliminarysurveyofthecavesoftheYucatanPenin sula: AssociationforMexicanCaveStudiesBulletin,v.6,p.215296. Figure3.ProfilesatanentrancetothehorizontalQuebradaSystem(Chank anaab)forinstrumentdivingtime,dissolved oxygen,percentageofoxygen,temperature,salinity,andpH. C ENOTES ( ANCHIALINECAVES ) ON C OZUMEL I SLAND ,Q UINTANA R OO ,M E ´ XICO 254 N JournalofCaveandKarstStudies, August2007 arecordofotherfeaturesnotpreviouslyreported.Wealso foundasignificantnumberofaguadas.Itisevidentthat thedensetropicalforestmakesthecenoteentrances difficulttofind.Despitethefactthattheroadnetwork correlatessomewhatwiththepreviouslyknowncenotes, ourapproachresultedinidentificationofthebiggest sinkholesonthewestsideoftheisland.Theislandis mainlycomposedoflimestone(WurlandGiese,2005),and theformationofallthecenotesisduetocarbonate dissolution.Wehaveinsufficientdatatosuggestapattern ofdistributionofthesesystemsontheisland. Atsomesites,thefreshwatertableisshallowand superficial.Thisisimportant,becausethehumanpopula- tionoftheislandhasbeenincreasingduringthepast 5years,withaconsequentincreaseinwaterdemand.At thesametime,thisincreaseinpopulationalsoincreases residualwasteandcontaminationthatcouldpercolateinto subterraneanenvironments.Thissituationcouldcause alossofwaterqualityandalsodamageunderground biodiversity.Thiscouldbethereasonwefoundseveral specieslivingonlyinthebrackishwaterinalmostallofthe cenotes. Inthephysicalanalyses,wefoundthattheground waterofCozumelhasseveralzones.IntheAerolitoand Quebradahorizontalsystems,themixingflowtotheseais important.Conversely,intheTresPotrillosandXkan-ha verticalholes,stratificationwithfewmixingperiodsduring theyearwasfound.Thehaloclineandthermoclineare clearlydefinedinthesesystems. Althoughfreshwaterfishareimportantinthecenotesof Cozumel,theyliveinthesuperficialwaterlayer(Schmitter- Soto,1999).Wereportaspeciesrichnessfromeach sinkholemainlycomposedofcrustaceans,includingspecies specializedtocavelife.Thesespecieshaveslightrelation- shipswithspeciesfromotherplaces.Forexample,during therecentexplorations,werecordedthreecenotesin- habitedbymembersofthegenus Procaris ,buttheyall areprobablydifferentspecies(Mej ´ a-Ort ´ zetal.,2006). Thesespeciesareinterestingbecausetheyarephylogeneti- calyrelatedtoorganismsfromtheBahamasandHawaii. Untilnow,theseanimalshavenotbeenrecordedonthe Yucata ´nPeninsula(SternbergandShotte,2004),butwe cannotexcludethattheymightbelivinginunderwater cavesthere. Severalgeneraoftermobaenacenshavebeenreported mainlyinItaly,andinsomecases,ontheBahamasIslands. Termobaenaceansconsideredofthemonotypicgenus Tulumella havebeenreportedpreviouslyattwolocalities inMe ´xico,innearbysystemsofTulum,Yucata ´n(Illife, 1992and1993),andonCozumelIsland,specificallyinthe CuevaQuebradaSystem.Butindividualspecieshavenot beendeterminedthere.Inthisstudywereportasecond cenotewherethesecrustaceanslive,anddeterminedthat theyaremembersofthegenus Tulumella ,butpresumably ofanundescribedspecies. Otherinterestingcrustaceansthatwefoundinacen- oteonCozumelIslandarethoseofthegenus Barbouria . Todate,thisgenushasonlyauniquespecies Barbouria cubensis ,andithasbeenreportedonotherislands(Hobbs etal.,1977).Wehavealsoidentifiedorganismsofthe genus Bahalana insinkholesthatareapparentlyuncon- nected. C ONCLUSIONS Withthisstudyweincreasetheknownnumberof identifiedcenotesonCozumelIsland,andforthefirsttime givetheirexactgeographicpositions.Itisimportanttosay thatseveralcenotesareundercoverinthetropicalforest, andthisinaccessibilityhaslimitedsurveysthere.Becauseof thehumanpopulationincreaseanditsincreasingwater demand,theseenvironmentsarepotentiallyindangerof severedamage.Also,wereportforthefirsttimethe physicalwaterparametersofthreecenotesontheisland, andconcludethatthemaincomponentofthesewatersis salineatshallowdepths. Figure2.OnCozumelIsland,crosseslocatethelargest aguadas(shallowwaterbodies),andletterskeyedtoTable1 locatecenotes. L.M.M EJI ´ A -O RTI ´ Z ,G.Y A ´ N EZ ,M.L O ´ PEZ -M EJI ´ A , AND E.Z ARZA -G ONZA ´ LEZ JournalofCaveandKarstStudies, August2007 N 253 Table1.CenotesonCozumelIsland. Cenote a Latitude ( u N) Longitude ( u W) Length (m) Depth (m)FaunaReference (a)RanchoSanMiguelCenote20 u 30 40 86 u 53 55 8.03.0Freshwaterfish (b)RanchoSanMiguel120 u 30 15 86 u 53 55 9.02.0Freshwaterfish (c)CenotedelDr.Villanueva20 u 30 20 86 u 53 10 12.04.0Cavecrustaceans (d)CenoteBambu20 u 29 35 86 u 52 30 61.051.8Freshwaterfish,turtles,snakes (e)UniversidaddeQuintana Roo 20 u 29 30 86 u 56 45 15.01.5Freshwaterfish,landcrabs,turtles (f)CenoteChu-ha(San Francisco) 20 u 29 25 86 u 57 20 38.118.3FreshwaterfishMilhollin,1996 (g)Aerolito a 20 u 28 00 86 u 58 45 18.37.0Cavecrustaceans,marinefish,Cave echinoderms,caveworms Kensley,1988;Mej ´ a-Ort ´ zet al.,2006,inpress (h)Xkan-ha20 u 27 55 86 u 57 15 80.035.0Cavecrustaceans,freshwaterfish, turtles Kensley,1988;Mej ´ a-Ort ´ zet al.,2006 (i)TresPotrillos20 u 27 05 86 u 59 15 94.038.1Cavecrustaceans,freshwaterfishYan ez-Mendoza,1999; Mej ´ a-Ort ´ zetal.,2006 (j)Km1(QuebradaSystem) b 20 u 26 40 86 u 59 45 6.05.0Cavecrustaceans,freshwaterfishBowman,1987;Holsinger, 1992;SternbergandShotte, 2004;Mej ´ a-Ort ´ zetal., 2006 (k)RokaBomba(Quebrada System) b 20 u 26 40 86 u 59 40 2.05.0Cavecrustaceans,freshwaterfishBowman,1987;Holsinger, 1992;SternbergandShotte, 2004;Mej ´ a-Ort ´ zetal., 2006 (l)Cilpa(QuebradaSystem) b 20 u 26 45 86 u 59 20 2.04.0Marinecrustaceans,freshwaterfishBowman,1987;Holsinger, 1992;SternbergandShotte, 2004;Mej ´ a-Ort ´ zetal., 2006 (m)CenoteCocodrilo b 20 u 23 00 87 u 01 10 2493.017.4CavecrustaceansMej ´ a-Ort ´ zetal.,2006 (n)SanAndre ´sElCedral20 u 22 50 87 u 00 30 15.04.0Freshwaterfish,crustaceans (o)RanchoJuvencioElCedral20 u 21 20 86 u 59 55 8.03.0Freshwaterfish,crustaceans (p)Cenote1,RanchoElChino ElCedral 20 u 20 20 86 u 59 40 12.05.0Freshwaterfish,turtles (q)Cenote2,RanchoelChino ElCedral 20 u 19 10 86 u 56 05 3.01.0Freshwaterfish,turtles (r)Cenote3,RanchoelChino ElCedral 20 u 21 20 86 u 55 20 5.01.5Freshwaterfish,turtles a LettersinfrontofeachcenotecorrespondstolocationonFigure2. b Denotesseaconnection. C ENOTES ( ANCHIALINECAVES ) ON C OZUMEL I SLAND ,Q UINTANA R OO ,M E ´ XICO 252 N JournalofCaveandKarstStudies, August2007 locationsandexaminethemainfeatures.Geographic positionswereregisteredusingaGarminGlobalPosition- ingSystem(GPSSummit12channels)usingtheNAD27 MapDatum,andallpositionswereroundedtotheclosest 5seconds.Weobtainedmapsforthreelargecenotesfrom theliterature,andthenweexploredtheminorderto corroboratethemapsurveysofthesesinkholes.Wealso recordedphysicaldatausingaHydrolabDataSonde5to measuretemperature,salinity,dissolvedoxygen,depth, light,andpH,andcollectedanimalslivingthere.Allthe cenoteswereplottedonamapandlisted. R ESULTS Weregistered18cenotes,mostofthemhavingsalt waterintheirdeeperlayers,whicharelistedinTable1, includingtheirgeographiclocationsandfauna.Wealso registered250shallowwaterbodies(cenotes-aguadas), fromwhichonlythelargerareshownonFigure2.The mainwaterbodiesareclosetothecoast,andothersthatlie intheinnerpartoftheislandaredifficulttoidentify becausethetropicalforestisverydense.Duringour explorations,wefoundfreshwaterfishandturtlesasthe mainfaunainalmostalltheaguadas.Inmostofthe cenotes,however,werecordedsaltorbrackishwaterat deeperlevels.Asexamples,weshowhereverticaland horizontalprofilesfromthreecenotes:TresPotrillos, Xkan-ha,andCenoteKm1(QuebradaSystem)(Figs.3 and4respectively).Duringtheanalyseswefoundlight penetrationtooccuronlyinthesuperficialwater(23m) oftheverticalcenotes,andalsotoaveryshallowdepth (3m)ofthehorizontalsystem.Thehaloclineappearson thegraphs,anddissolvedoxygenwasrecordedatverylow concentrations(Figs.3and4).OnlytheQuebradaand AerolitoSystemshavedirectseaconnectionsfromwhere wecollectedcrustaceans,echinoderms,worms,andmainly marinespeciesoffish. D ISCUSSION Thisstudydealswithseveralwaterbearingfeatures aroundCozumelIsland.Otherauthorshavereported previouslyondifferentfeaturesontheisland(Yan ez- Mendoza,1999;Bowman1987;Kensley,1988;Reddell, 1977,1981).Here,wereportthepreciselocationofthese features,thephysicalparametersofthreeofthem,and Figure1.IndexmapstothestateofQuintanaRooandCozumelIsland. L.M.M EJI ´ A -O RTI ´ Z ,G.Y A ´ N EZ ,M.L O ´ PEZ -M EJI ´ A , AND E.Z ARZA -G ONZA ´ LEZ JournalofCaveandKarstStudies, August2007 N 251 CENOTES(ANCHIALINECAVES)ONCOZUMELISLAND, QUINTANAROO,ME ´ XICO L UIS M.M EJI ´ A -O RTI ´ Z 1 ,G ERMA ´ N Y A ´ N EZ 2 ,M ARILU ´ L O ´ PEZ -M EJI ´ A 1,3 , AND E STEBAN Z ARZA -G ONZA ´ LEZ 4 Abstract: CozumelIslandisaCaribbeanlocalehavingkarstasthemaincomponentofi ts surface.Knowncavesaresteep-sided,water-filledsinkholes(cenotes) ,andalmostallofthem areconsideredtobeanchialinecavesbecausetheyhaveseawaterconnecti ons.Inorderto identifythelocationofasmanycenotesaspossibleontheisland,webased ourstudyinitially onaerialphotographs.Thiswasfollowedbyvisitstoeachsiteforfieldve rificationand collectionofphysicaldataandbiologicalspecimens.Weexploredsevera lcenotestorecord physicaldatasuchastemperature,salinity,dissolvedoxygen,depth,pH ,light,andtocollect theanimalslivingthere.Asaresult,wereportoneighteencenotesonCozu melIsland,their locationandfauna.Physicaldatafromthreecenotesshowedthatthefresh waterisverythin atthetopofthewatertable.Mostofthesystemsaremarinewater-filled.V aryingdegreesof connectionexistbetweenthesesinkholesandtheocean.Inaddition,othe rwaterbodieswere foundnottobecenotes,butaguadas(shallowwaterbasins). I NTRODUCTION InMe ´xicoabout20percentofthelandconsistsof karst,andby1981about1024caveswereknownaround thecountry(Reddell,1981).ParticularlyontheYucata ´n Peninsula,theunderlyingrockisexclusivelycalcareous.In thatregion,cenotesarethemainwaterbodies.Gaona- Vizcaynoetal.(1980)definedthemassubterraneanwater bodieswithsomeconnectiontothesurface.Hall(1936) classifiedthecenotesonthepeninsulaintofourtypes: cenotes-ca ´ntaro(surfaceconnectionnarrowerthanthe diameterofthewaterbody),cenotes-cil ´ ndricos(vertical walls),cenotes-aguadas(shallowwaterbasins),andgrutas (horizontalentrancewithdrysections). ThetopographyofCozumelIslandismainlykarstic, andithasallfourkindsofcenotes.Whentheseconduits haveseaconnections,weknowthemasanchialinecaves. Thelocalpeopleusethefreshwaterfromtheseholesto satisfytheirbasicwaternecessities.Somecenoteson CozumelIslandhavebeenpreviouslyreported,suchas CuevaRanchoSantaRita(Reddell,1977),CuevaQueb- radaParquedeChankanaab(Bowman,1987;Holsinger, 1992),CenoteXkan-haandCenoteAerolito(Kensley, 1988).OnCozumel,wealsofindshallowsediment-floored bodiesofsuperficialwatercalledaguadas.CozumelIsland iscoveredbytropicalforest,sotheshallowwaterbodies (aguadas)andthedeepholes(cenotes)arenotalways easilyfound.Inaccessibilityisthemainreasonthatfew cenoteshavebeenpreviouslycatalogued. Thisworkaimedtoidentifythecenotesandaguadason CozumelIsland,theirgeographiclocation,fauna,and somephysicalqualities.Wealsoconductedsurveysto obtainverticalprofilesofphysicaldataintwodeeperholes (TresPotrillosandXkan-ha),andonefromtheQuebrada System(ahorizontalcenote). S TUDY A REA CozumelIslandliesbetween20 u 16 12 and20 u 35 15 N latitude,andbetween87 u 01 48 and86 u 43 48 Wlongi- tude,andhasanareaof482km 2 .TheIslandisoffthe northeasterntipoftheYucata ´nPeninsula,intheMexican partoftheCaribbeanSea,anditsmainfreshwatersources arethecenotesandsubterraneanwaterconduits(Fig.1). CozumelispartoftheEastMayaPlatewith sedimentaryrocksformedonawideplatform.Wurland Giese(2005)reportthatcoredrillingsindicatethatthe islandisformedfromreefsedimentwithathicknessof 100mormore,whichdatesfromtheOligoceneand QuaternaryEpochs.Akarsticaquiferhasbeendeveloped intheselimestonebeds. M ATERIALSAND M ETHODS Weanalyzedaerialphotographstakenduringthedry season(Feb.9,2000)at1:75,000fromInstitutoNacionalde Estad ´ sticaGeograf ´ aeInformatica:SistemaNacionalde Fotograf ´ aAe ´rea(INEGISINFA),andidentifiedbodies ofsurfacewater.Inaddition,wereviewedtheliteratureof speciesdescriptionsfromCozumel,andwelistedthe cenotesreported.Subsequently,wemadeseveralvisits during2005tothoseplacestocorroboratetheirgeographic 1 Lab.deBioespeleolog ´ ayCarcinolog ´ a,Divisio ´ndeDesarolloSustentable,Depto. CienciasyHumanidades,UniversidaddeQuintanaRooCozumel,Av.Andre ´s QuintanaRoos/n,Col.SanGervasio,Cozumel,QuintanaRoo,CP77640Me ´xico luismejia@uqroo.mx 2 YucatechExpeditions,AP533,CozumelQuintanaRoo,CP77600Me ´xico german@yucatech.net 4 PostgradoenCienciasdelMaryLimnolog ´ a,InstitutodeCienciasdelMary Limnolog ´ a,Un ´ versidadNacionalAnto ´nomadeMe ´xico,Me ´xicoestebanzarza76@ yahoo.es 3 marlopez@uqroo.mx L.M.Mej ´ a-Ort ´ z,G.Ya ´n ez,M.Lo ´pez-Mej ´ a,andE.Zarza-Gonza ´lezCenotes(anchialinecaves)onCozumelIsland,QuintanaRoo, Me ´xico. JournalofCaveandKarstStudies, v.69,no.2,p.250255. 250 N JournalofCaveandKarstStudies, August2007 Reddell,J.R.,1981,AreviewofthecavernicolefaunaofMexico, Guatemala,andBelize:TexasMemorialMuseumBulletin,v.27, p.1327. Schmitter-Soto,J.J.,1999,Distributionofcontinentalfishesinnorth ern QuintanaRoo,Mexico:SouthwesternNaturalist,v.44,p.166 172. Sternberg,R.,andShotte,M.,2004,Anewanchialineshrimpofthegenus Procaris (Crustacea:Decapoda:Procarididae)fromtheYucatan Peninsula, in BiologicalSocietyofWashingtonProceedings,v.117, p.514522. Yan ez-Mendoza,G.,1999,Cozumelsunderground:Sources,Journalof UnderwaterEducation,v.11,no.3,p.3435. Wurl,J.,andGiese,S.,2005,GroundwaterqualityresearchonCozumel Island,StateofQuintanaRoo,Mexico, in FraustoMart ´ nez,O.,ed., DesarrolloSustentable:Turismo,costasyeducacio ´n,Universidadde QuintanaRoo,p.171176. Figure4.VerticalprofilesatCenoteTresPotrillos(a,b,andc)andCenot eXkan-ha(d,e,andf)fordissolvedoxygen( o ) percentageofoxygen(*)temperature( X ),salinity( % ),andpH( D ). L.M.M EJI ´ A -O RTI ´ Z ,G.Y A ´ N EZ ,M.L O ´ PEZ -M EJI ´ A , AND E.Z ARZA -G ONZA ´ LEZ JournalofCaveandKarstStudies, August2007 N 255