Acid Rain Effects on Adirondack Streams—
Transcript of Acid Rain Effects on Adirondack Streams—
U.S. Department of the InteriorU.S. Geological Survey
Fact Sheet 2009-3075 October 2009Printed on recycled paper
Key Findings
Acidrainhasacidifiedsoilsresultingintoxicaluminumin66percentof565assessedstreams.
Diatoms,anenvironmentallysensitivegroupofalgae,weremoderatelytoseverelyaffectedbyacidrainin80percentofassessedstreams.
Aquaticinsectsandrelatedorganismsreferredtoasmacroinvertebratesweremoderatelytoseverelyaffectedin52percentofassessedstreams.
Recoveryfromacidificationhasbeenminimalin11of12Adirondackstreamssampledpreviouslyintheearly1980s.
Thebase-cationsurplus,anewacidificationindexdevelopedforthisproject,indicatedthatnotmorethanone-thirdofmeasuredstreamaciditywasfromnaturalsources.
TraditionallylakeshavebeenthefocusofacidrainassessmentsintheAdirondackregionofNewYork.However,thereisagrowingrecognitionoftheimportanceofstreamsasenvironmentalindicators.Streams,likelakes,alsoprovideimportantaquatichabitat,butstreamsmorecloselyreflectacidraineffectsonsoilsandforestsandaremorepronetoacidificationthanlakes.Therefore,alarge-scaleassessmentofstreamswasundertakeninthedrainagebasinsoftheOswegatchieandBlackRivers;anareaof4,585km2inthewesternAdirondackregionwhereacidrainlevelstendtobehighestinNewYorkState.High flows such as seen in this Adirondack stream tend to have the most acidic stream water.
Acid Rain Effects on Adirondack Streams— Results from the 2003–05 Western Adirondack Stream Survey (the WASS Project)
Purpose of the Western Adirondack Stream Survey (WASS)AcidifiedsurfacewaterswerefirstdiscoveredintheAdirondackregion
ofNewYorkinthe1970s.ComprehensivemonitoringandassessmentofAdirondacklakes,ongoingsincetheearly1980s,hasidentifiedthisregionasoneofthemostaffectedbyacidicdepositioninNorthAmerica.However,assessmentsofstreamacidificationintheAdirondackregionhavebeenlimitedtoalargesurveyintheearly1980sandintermittentdatacollectiononafewstreamsthroughthe1980sand1990s.
Lakechemistryandstreamchemistryaregenerallysimilarwithinaregion,butlakechemistrycanbeanunreliableindicatorofstreamchemistrywhenassessingtheeffectsofacidicdeposition.Streamsaremorepronetoacidificationthanlakesbecausetheyreceivealargerfractionofwaterfromshallowsoilsthatareoftenineffectiveatneutralizingacidity.Lakesarealsoabletobuffertheacidityofstoredwaterbyin-lakeprocesses.
Streamacidificationismostprevalentduringperiodsofhighflow.Thetransientnatureofhighflow,whichcanlastfromafewhourstoafewweeks,resultsinepisodicacidificationthatisdifficulttomeasure.Thechemistryduringbaseflow(periodsbetweenstormsorrapidsnowmeltwhenchemicalconcentrationstendtoberelativelystable)iseasiertomeasure,butunderestimatestheextentoftheproblem.Forexample,inaCatskillMountainwatershed,thetotallengthofacidifiedstreamswasfoundtoincreasefrom16percentatbaseflowto82percentathighflow(Lawrence,2002).Harmfuleffectsonaquaticlifefromepisodicacidificationcanbesimilarorworsethanthosefromchronicacidification(McComickandLeino,1999;Passyandothers,2006).
ToassessthecurrentchemicalandbiologicalconditionsofstreamsintheregionoftheAdirondacksconsideredmostaffected,theWesternAdirondackStreamSurvey(WASS)wasconductedbytheU.S.GeologicalSurvey(USGS)incollaborationwiththeAdirondackLakesSurveyCorporation,theNewYorkStateDepartmentofEnvironmentalConservation,andtheUniversityofTexasatArlington,withfundingsupportfromtheNewYorkStateEnergyResearchandDevelopmentAuthority.ThisprojectisthefirstregionalassessmentofAdirondackstreamssincetheearly1980sandtheonlyassessmentconductedintheUnitedStatestocharacterizeepisodicacidificationonaregionallevel.
Project Objectives
• Developanimprovedmethodfordistinguishingbetweenthechemicaleffectsofacidicdepositionandtheeffectsofacidityfromnaturalsources.
• Determinethecurrentextentofeffectsofacidicdepositiononstreamchemistryandaquaticlifeinthisregion.
• Evaluatetheroleofsoilchemistryasacontrolofstreamchemistry.
• Determinetotheextentpossiblechangesinstreamchemistryoverthepasttwodecades.
Study ApproachThestudywasundertakeninthedrainagebasinsoftheOswegatchie
andBlackRivers,anareaof4,585squarekilometers(km2)inthewesternpartoftheAdirondackregionofNewYork.Atotalof200streamsrepresentingapopulationof565accessiblestreamswererandomlyselectedforsampling.Thepopulationofstreamshadminimalupstreaminfluencesfromlakesandponds.
Figure 1. Collection of a water sample from Buck Creek, Inlet, NY, during spring snowmelt. Ongoing monitoring of flow and water chemistry at this site provided valuable data on how variations in flow affected stream chemistry.
Fivesurveyswereconductedduringspringsnowmelt,summerlowflow,andfallhighflowtoaccountforvariationsinchemistrythatoccurredbothepisodicallyandseasonally.Allsamplesforeachsurveywerecollectedwithin3days(withafewexceptions)duringperiodswhenflowswereeitherelevatedorremainedlow.BuckCreek(drainagearea3.1km2),theonlystreaminthestudyregionmonitoredyear-roundforflowandchemistry,wasusedasanindexstreamtoplaceresultswithinthecontextofvariationsthroughoutthestudy(fig.1).
A New Chemical Index for Measuring AcidificationAssessmentsofacidicdepositioneffectsandrecoveryhave
reliedonANCGandpHastheprimarychemicalindicators.However,bothofthesemeasurementscanbesubstantiallyinfluencedbynaturallyproducedorganicacidity,whichisabundantinmanyAdirondackstreams.Tobetterdistinguishbetweenacidicdepositionandnaturalorganicacidity,anewchemicalindex,termedthebase-cationsurplus(BCS),wasdevelopedinthisproject.TheBCSisbasedonthemobilizationofinorganicaluminum(thetoxicform)withinthesoil,whichdoesnotoccurintheabsenceofacidrain.ABCSvaluelessthan0microequivalentsperliter(µeq/L)instreamwaterindicatesthatthesoilhasbecomesufficientlyacidifiedbyacidraintoenabletoxicformsofaluminumtomovefromthesoilintostreams(fig.2).MeasurementsoftheBCSinstreamsvariedseasonallyandwithchangesinflow.ResultsshowedthatstreamswithaBCSvaluebelow25µeq/LduringanyofthestreamsurveyswerelikelytohavenegativeBCSvaluesatsometimeoverthecourseofagivenyearandwerethereforedefinedaspronetoacidification.
Effects on the Chemistry of Stream and SoilsResultsshowedthat66percentofassessedstreams
werepronetoacidificationbyacidrain(BCSvalueslessthan25µeq/L).Ofthesestreams,approximatelyone-halfwerechronicallyacidifiedandone-halfwereepisodicallyacidified(acidifiedduringhighflows).Theprevalenceofacidifiedstreamsincreasedfromwesttoeastacrossthestudyregion(fig.3).Resultsalsoshowedthat718kilometers(km)oftotalstreamlengthwaspronetoacidificationwithinthestudyregion,althoughmorethan3,000kmofstreamsinthestudyregionwerenotassessedduetoinaccessibility.Naturalsourcesofaciditywerefoundtocontributeonly16to34percentoftheaciditymeasuredbytheBCS.
NeutralizationofacidityisdependentonrapidreactionsinthesoilthatbufferthepHofsoilwaterthroughthereleaseofbases(mostlycalcium)adsorbedtoparticlesurfaces(Lawrence,
ChemicalmeasurementsincludedpHandacid-neutralizingcapacitybyGrantitration(ANCG),themostcommonlyusedmeasuresofacidificationeffects.However,pHandANCG donotdistinguishbetweennaturalorganicacidity,whichiscommoninAdirondackwaters,andthatderivedfromacidicdeposition.Therefore,anewmeasure,termedthebase-cationsurplus(BCS),wasdevelopedtorelateacidicdepositioninputstothebufferingthresholdofsoilsbelowwhichtoxicaluminumismobilizedandenterssurfacewaters.Soilsamplesalsowerecollectedin11smallwatershedstoidentifylinksbetweensoilchemistryandstreamchemistry.
Diatoms,ahighlydiversegroupofalgaewithvariableenvironmentaltolerances,andmacroinvertebrates(insectsandotheraquaticlifesuchaswormsandcrustaceans)wereusedasbiologicalindicatorsinthisstudy.Diatomsampleswerecollectedineachofthe200surveystreamsduringthesurveysconductedinAugust2003,October2003,March2004,andAugust2004.Macroinvertebrateswerecollectedin36streamsthatrepresentedtherangeofacidification.
HistoricalmeasurementsofANCG,pH,andspecificconductancewereavailableintheearly1980sfor18Adirondackstreamsandlakeoutletswithinthestudyregion.Thehistoricalsamplingwasreplicatedinthisstudyduring2003–2005todetermineifwaterchemistrydifferedbetweenthetwoperiods.Becausestreamchemistryisstronglyinfluencedbyflow,datafromtheUSGSstreamgageontheIndependenceRiveratDonnattsburgwereusedtoaccountforflowvariationsduringbothsamplingperiods.
Figure 2. Concentrations of inorganic aluminum (the form toxic to aquatic life) plotted against values of the base-cation surplus to illustrate the threshold below which aluminum is mobilized in soils and transported into streams.
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Figure 4. A typical upper soil profile in Adirondack soil. The Oa horizon, comprised mostly of humus-like material, lies directly below the litter and decomposing leaves of the forest floor. The upper B horizon, comprised primarily of mineral matter formed from the breakdown of rocks lies directly below the gray, relatively inert E horizon.
Figure 3. Acidification categories of sites sampled in the March 2004 survey. Sites not acidified had base-cation surplus (BCS) values greater than 25 microequivalents per liter (µeq/L); sites prone to acidification had BCS values greater than 0 µeq/L but less than 25 µeq/L; acidified sites had BCS values less than 0 µeq/L.
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Figure 5. The percent of streams in each of three categories of acid impact, derived from the mean diatom acidification index (ACI) values across the four diatom surveys. ACI represents the proportion of species in a diatom community with preference for acidic conditions. (NON, non-impacted; MOD, moderately impacted; HIGH, highly impacted).
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2002).Ifinsufficientcalciumisavailable,toxicformsofaluminumareinsteadreleased.Soilsamplinginselectedwatershedsshowedacloserelationshipbetweentheavailabilityofbasesinthesoil,referredtoasthebasesaturation,andtheBCSinstreamwater.Throughthisrelationship,basesaturationintheupperBhorizonwasestimatedtobeinsufficienttopreventaluminummobilizationin90percentoftheassessedwatersheds.TheupperBhorizonhadbeengenerallyconsideredtheprimarysourceofcalciumforbufferingduringhighflows,butWASSresultsindicatedthattheorganicsoilhorizonclosetothesurface(Oahorizon)playsagreaterrolethantheupperBhorizon(fig.4)intheneutralizationofacidity.TheneutralizingcapacityoftheupperBhorizonhasbeenloweredbythedepletionofcalciumfromacidrain.
Effects on Aquatic lifeAssessmentofdiatomsshowedthatonlythemostacid-
tolerantspecieswerefoundbelowaBCSvalueof10µeq/L,whichapproachesthethresholdformobilizationofinorganicaluminum(BCS=0µeq/L).Thepercentageofstreamsinwhichdiatomcommunitiesweremoderatelyorseverelyimpactedbyacidicdepositionrangedfrom66to80percent(fig.5).Limitedvariationwasobservedinvaluesofthemeandiatomacidificationindex(ACI)amongthefoursurveysdespitetheconsiderablevariationinflow,season,andwaterchemistry.Whereasawatersamplereflectschemicalconcentrationsat
Figure 6. Collection of macroinvertebrates in an Adirondack stream by a scientist in the Stream Biomonitoring Unit of the New York State Department of Conservation.
themomentofcollection,thepresenceorabsenceofadiatomindividualreflectsenvironmentalconditions,includingwaterchemistry,overtheorganism’slifespan.ThesimilarityinACIvaluesfortheOctober2003andMarch2004surveysmostlikelyreflectsacidificationduringtheseveraldaysthatthesurveysoccurred.However,theACIvaluesfortheAugust2004survey,whichwassimilartotheOctober2003andMarch2004surveys,indicatesexposuretoacidificationatsometimepriortothesurvey.Thetimebetweentheexposureandthesurveywastooshortforrecoveryoftheacid-sensitivediatomspecies.Therefore,thediatomresultsreflectedvariationsinstreamchemistryoverapriorperiodofuptoseveralweeks,acharacteristicthatmakesdiatomshighlyvaluableintheassessmentofstreamacidificationwherewaterchemistrycanvarysubstantiallyoverafewhours.IntheAugust2003survey,33ofthe162samplestreamsweredryduetoextremelydryconditions.
Macroinvertebratesamplingof36streams(fig.6)withvaryingchemistrywasusedtocharacterizetherangeofacidificationimpactsonmacroinvertebratecommunitiesandtodefinecategoriesofbiologicalimpactbasedontherelationshipsamongBCS,aluminum,andanewAcidBiologicalAssessmentProfile(acidBAP)indexthatrelatesthemacroinvertebratecommunitytowaterchemistry.UsingtheMarch2005surveyresultsasthemedianchemicalcondition,52percentofthestreamshadmacroinvertebratecommunitiesthatweremoderatelytoseverelyaffectedbyacidrain.
Changes in Stream Chemistry Since the Early 1980sAcomparisonwithhistoricalstreamchemistrydata
showedstatisticallyhigherpHvaluesin2003–2005thanintheearly1980sin8ofthe12streamsand4ofthe6lakeoutlets,butlessthanone-halfofthesestreamsandoutletshadahigher
ANCGin2003–2005thanintheearly1980s.Theamountofchangewasrelativelysmall,andnearlyallthestreamsandoutletsexhibitedepisodicacidificationduringperiodsofhighstreamflowin2003–2005.
TheresultsindicatedthatrecoveryfromacidificationintheseAdirondackstreamsandoutletshasbeenminimal,withtheexceptionofBaldMountainBrookandFlyPondOutlet.However,eveninthesewaters,BCSvaluesduringthemostacidicsamplingconditionsin2003–2005approached0µeq/L;thethresholdformobilizationoftoxicaluminum.TheoverallincreaseinANCGforthe12streamswas13µeq/Lover23years.Thedegreeofchemicalrecoveryobservedinthishistoricalcomparisonprobablyresultedinlittleornobiologicalrecoveryinmostofthestreamsandoutlets.
ConclusionsTheWASS,thelargeststreamsurveyconductedin
theUnitedStatestocharacterizeepisodicacidification,hassubstantiallyexpandedourknowledgeofthecurrentconditionsofAdirondacksurfacewaters.Currenteffortstomodelchangesinsoilandwaterchemistryinresponsetochangesinatmosphericdepositionwillbenefitfromthedatacollectedinthisstudy,butadditionaldatawillbeneededtodocumenttheeffectsofenvironmentalchanges.Futuretrendsinatmosphericdepositionareuncertain,andupwardtrendsintemperatureandprecipitationinthestudyregion(Dello,2007)areexpectedtocontinue(Hayhoeandothers,2007).WASSresultswillbevaluableinthisregardbecausethestudycanberepeatedtoevaluatefuturechangesinstreamchemistryandbiotaunderbothbaseflowandepisodicconditions.
References Cited
Dello,K.,2007,TrendsinClimateinnorthernNewYorkandwesternVermont:Albany,NY.,StateUniversityofNewYork,UniversityatAlbany,M.S.thesis.
Hayhoe,K.,Wake,C.P.,Huntington,T.G.,Luo,L.,Schwartz,M.D.,Sheffield,J.,Wood,E.,Anderson,B.,Bradbury,J.,DeGaetano,A.,TroyT.J.,andWolfe,D.,2007,PastandfuturechangesinclimateandhydrologicalindicatorsintheUSNortheast:ClimateDynamics,v.28,p.238–407.
Lawrence,G.B.,2002,Persistentepisodicacidificationofstreamslinkedtoacidraineffectsonsoil:AtmosphericEnvironment,v.36,p.1589–1598.
McComick,J.H.,andLeino,R.L.,1999,Factorscontributingtofirst-yearrecruitmentfailureoffishesinacidifiedwaterswithsomeimplicationsforenvironmentalresearch:TransactionsoftheAmericanFisheriesSociety,v.128,p.265–277.
Passy,S.I.,Ciugulea,I.,andLawrence,G.B.,2006,DiatomdiversityinchronicallyversusepisodicallyacidifiedAdirondackstreams:InternationalReviewofHydrobiology,v.91,p.594–608.
AcknowledgmentsSupportfortheWesternAdirondackStreamSurveywasprovidedbytheNewYorkStateEnergyResearchand
DevelopmentAuthority(NYSERDA);theU.S.GeologicalSurvey(USGS);theNewYorkStateDepartmentofEnvironmentalConservation,DivisionofAirResourcesandDivisionofFish,WildlifeandMarineResources;andtheAdirondackLongTermMonitoringProgramconductedbytheAdirondackLakesSurveyCorporation.WatershedmonitoringdataatBuckCreekwasprovidedbytheAdirondackEffectsAssessmentProgramconductedbytheRensselaerPolytechnicInstituteincooperationwiththeUSGS.AdditionalsupportfortheBuckCreekWatershedStudywasprovidedbyNYSERDA.
Additional information on the Western Adirondack Stream Survey can be found in the following publications:Baldigo,B.P.,Lawrence,G.B.,Bode,R.W.,Simonin,H.A.,Roy,K.M.,andSmith,A.J.,2009,ImpactsofacidificationonmacroinvertebratecommunitiesinstreamsofthewesternAdirondackMountains,NewYork,USA:EcologicalIndicators, v.9,p.226–239.
Lawrence,G.B.,Roy,K.M.,Baldigo,B.P.,Simonin,H.A.,Capone,S.B.,Sutherland,J.S.,Nierswicki-Bauer,S.A.,andBoylen,C.W.,2008,ChronicandepisodicacidificationofAdirondackstreamsfromacidrainin2003–2005:JournalofEnvironmentalQuality,v.37,p.2264–2274.
Lawrence,G.B.,Roy,K.M.,Baldigo,B.P.,Simonin,H.A.,Passy,S.I.,Bode,R.W.,andCapone,S.B.,2008,Resultsfromthe2003–2005westernAdirondackstreamsurvey:NewYorkStateEnergyResearchandTechnologyAuthorityFinalReport08–22(November2008),variouslypaged,availableonlineathttp://www.nyserda.org/programs/Environment/EMEP/finalreports.asp.
Lawrence,G.B.,Sutherland,J.W.,Boylen,C.W.,Nierzwicki-Bauer,S.A.,Momen,B.,Roy,K.M.,Baldigo,B.P.,Simonin,H.A.,andCapone,S.B.,2007,Acidraineffectsonaluminummobilizationclarifiedbyinclusionofstrongorganicacids:EnvironmentalScienceandTechnology,v.41,p.93–98.
By Gregory B. Lawrence1, Karen M. Roy2, Barry P. Baldigo1, Howard A. Simonin3, Sophia I. Passy4, Robert W. Bode3, and Susan B. Capone5
1 U.S. Geological Survey.
2 New York State Department of Environmental Conservation.
3 Retired, formerly New York State Department of Environmental Conservation.
4 The University of Texas at Arlington.
5Adirondack Lakes Survey Corporation.
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