2011 update Dan Bogan Alaska Natural Heritage … Natural Heritage Program University of Alaska...
Transcript of 2011 update Dan Bogan Alaska Natural Heritage … Natural Heritage Program University of Alaska...
WhatisDidymo? Freshwater,stalkeddiatomcommonlycalled“RockSnot”
NativetoAlaska’scoldoligotrophicwaters
Canformdensematsonstream/lakebottoms
Tendstothriveinwaterswithabundantlight,stableflowregimes,highN:Pratios
Shouldwe(inAK)beconcerned? TheincidenceofdidymocoveredstreamshasincreasedinNorthAmericaoverthelast20years,notablyinwarmermoremesotrophicwaters
Unsightlydensemats(“nuisanceblooms”)arenotwelldocumentedinAlaskastreams
Anecdotally,matsareshowingupinstreamswheretheyhaven’tbeenseenbefore
Potentialnegativeecologicalimpact(s)ofdidymomats
Poten<alroleoffishermen Bothwelletal.(2009)madeaconvincingcaseforincreasedfishingpressureinfluencingthespreadofdidymoinBCrivers.
FirstappearanceofnusiancebloomsinBCriversintheearly1990scorrespondedwithincreasedfishingpressurefromnon‐Canadiansandtheadventoffelt‐soledwaders(1988).
Manyofthebloomshavesincesubsided.
DidymohistoryinAlaska Pite,etal.(2009)lookedatdiatomsfromsedimentcorestakenfromNaknekLakein2003.
Theyfounddidymovalvesthroughoutthecoredatingbackto1218,withnotrendsinabundancevariation
Varianceinvalvemorphologymaybepromisingindistinguishingnuisancestrains.
DidymohistoryinAlaska 2007wasthefirstreportednuisancebloomontheBrooksRiver
WeobtainedanothersedimentcorefromNaknekLakein2009
AimedforBrooksRiverdepositionzone
DidymohistoryinAlaska Wealsofoundnosignificantvariationindidymoabundancethroughoutthecore
IndexdiatomsfromBrooksRiverwerenotpresentinthecoreindicatingthatwemissedthetarget(BrooksR.depositionzone)
WouldliketotryagainandalsodosomemorphometricworktocompareBrooksRiverdidymovalveswithothernuisancedidymo
Geneticresearchison‐goingbySpaulding(percomm)attemptingtodetectdifferencesinnuisancestrains
beenattemptingtoverifyanddocumentaccountsofnuisancebloomsthroughoutthestate.
receivedsevenverifiedsamplesoverthepastfouryearsfromvariousagencypersonnel.
documentedseveralothernuisancebloomsinsouthcentral,interior,andsouthwestAlaska.
ReferencesBothwell,M.L.etal.2009.Onthebootsoffishermen:Thehistoryofdidymobloomson
VancouverIsland,BritishColumbia.Fisheries,vol.34,no.8:382‐388.Bothwell,M.L.etal.2008.DidbloomsofDidymospheniageminataaffectrunsof
anadromoussalmonidsonVancouverIsland?InBothwell,M.L.&S.A.Spaulding(eds),Proceedingsofthe2007InternationalWorkshoponDidymospheniageminata.CanadianTechnicalReportonFisheriesandAquaticSciences2795:50–53.
Pite,D.P.etal.2009.HistoricalabundanceandmorphologyofDidymospheniaspeciesinNaknekLake,Alaska.ActaBotanicaCroatica,Vol.68,No.2
Spaulding,S.&L.Elwell,2007.IncreaseinnuisancebloomsandgeographicexpansionofthefreshwaterdiatomDidymospheniageminata.Recommendationsforresponse.UnitedStatesGeologicalSurveyWhitePaperwebpublication,January2007:33pp.
Spaulding,S.A.etal.2008.ConfirmeddistributionofDidymosopheniageminata(Lyngbe)SchmidtinNorthAmerica.InBothwell,M.L.&S.A.Spaulding(eds),Proceedingsofthe2007InternationalWorkshoponDidymospheniageminata.CanadianTechnicalReportonFisheriesandAquaticSciences2795:26–29.
Sundareshwar,P.V.etal.2011.Didymospheniageminata:Algalbloomsinoligotrophicstreamsandrivers.GeophysicalResearchLetters,Vol.38
Whitton,B.A.etal.2009.BiologyofthefreshwaterdiatomDidymosphenia:areview.Hydrobiologia,630:1‐37.