Table Of ContentDOES CONSIDERATIONOFTHEWINDFIELDIMPROVEPREDICTIONS OF
ZOOPLANKTONABUNDANCEINHARP LAKE,ONTARIO?
MELANIEB.GORAL
ATHESIS SUBMITTEDTOTHEFACULTYOFGRADUATESTUDIES IN
PARTIALFULFILMENTOFTHEREQUIREMENTS FOR THEDEGREEOF
MASTER OFSCIENCE
GRADUATEPROGRAM INBIOLOGY
YORKUNIVERSITY
TORONTO,ONTARIO
AUGUST2012
©MELANIEB.GORAL, 2012
Abstract
Thepredictabilityofzooplanktonabundanceunderwind-drivencurrents has
rarelybeenexploredandfurtherstudycan helpimprovetheunderstandingof
zooplanktoncommunities inaquaticecosystems. Inthis study,wesought relationships
betweenthewindfieldandfortnightlyabundances of8zooplanktonspecies at amid-lake
stationinHarpLake,Ontariofrom 1980to2004.Overthestudyperiod,averagewind
speedhas declinedby25%,whiledirectionhas shifted21degrees towards thenorth.
Multiplelinearregressions weregeneratedtopredict seasonal andinterannual changes in
dailyzooplanktonabundancecombiningyear,Julianday,chemistryand,finally,wind
speedanddirection.Thewindfieldwas successfullyloadedintothesemodels for6ofthe
8species, althoughimprovements inpredictivepowerweremodest.Wesuspect that the
decreaseinwindspeedhas contributedtoachangeinzooplanktonheterogeneityinthe
lake,andthus achangeinbias oflake-wideabundanceestimates derivedfrom asingle
station.Zooplanktonarepatchilydistributed,but most long-term monitoringprograms
sampleonlyat onestation.Ourworksuggests that wemaywell beabletocorrect forany
bias emanatingfrom achangingwindfieldandimprovethepredictabilityofabundance.
ii
Acknowledgments
Afterall thework,turmoil andchaos, Ifinallymanagedtoachievemygoals, all
thanks toso manypeople. First ofall,toNormanYanwhogavemethewell-needed
constructivecriticisms, his patienceandunderstandingofmychaoticlife. ToKeith
Somers forhis constant statistical input whenIhadmylittlebrainlapses. ToRoberto
Quinlanforhis wonderful adviceandexpertisethat contributedtothesuccess ofmy
thesis. Tomyfamilywhowouldkeepmecompanyduringmyall-nighters and5am
epiphanies. Especially,IwouldliketothankJoewhoremainedbymysidewheneverI
felt likegivinguporneededtoheartheright thingtomotivateme! Most ofall,Iwould
liketodedicatemyentirethesis andits success tomylovinganddeparteddog,Holly.
Shewas theloveofmylifeandIcouldnot havedoneit without her,keepingme
companyandmakingmehappywhenIwas feelingstressed. Ithankyouso muchmy
angel.
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TABLE OFCONTENTS
Abstract……………………………………………………………………………….….ii
Acknowledgments……………………………………………………………………….iii
Tableof Contents………………………………………………………………………..iv
Listof Tables……………………………………………………………………………..v
Listof Figures…………………………………………………………………………..vii
Listof Appendices…………………………………………………………….…………ix
GENERAL INTRODUCTION………………………………………………………….1
References………………………………………….……………………………..7
CHAPTERONE
Thewindfielddoes not improvepredictions ofannual averagezooplanktonabundancein
HarpLake,Ontario
Abstract…………………………………………………………………….…....11
Introduction……………………………………………………………………..12
Methods………………………………………………………………………….20
Results…………………………………………………………………………...29
Discussion……………………………………………………………………….33
References………………………………………………………………………39
CHAPTERTWO
Canthepredictionofseasonal andlong-term zooplanktonabundanceinHarpLakebe
improvedusingthewindfieldat dailysteps?
Abstract………………………………………………………………………….77
Introduction……………………………………………………………………..78
Methods………………………………………………………………………….84
Results…………………………………………………………………………...92
Discussion……………………………………………………………………...100
References……………………………………………………………………..116
GENERAL CONCLUSION…………………………………………………………..149
References……………………………………………………………………...154
iv
Listof Tables
Table1.1: Physical andbehavioural characteristics offreshwatercrustacean
zooplanktonfrom HarpLake,Ontario…………………...………………47
Table1.2: Regressionmodels usingtheaverageabundanceofzooplanktonspecies
andBythotrephes P/A….………………………………………..……….48
Table1.3: Models usingtheaverageabundanceofzooplanktonspecies using
stepwisemultipleregressions andanannual predictor…………………..49
Table1.4: Pearson correlationcoefficients betweentheresidual abundanceof
zooplanktonandthewindfield……………………………………….....50
Table2.1: Thenumberofsamplingdates availableforthechosenspecies between
1980and2004inHarpLake,Ontario………………………………….122
Table2.2: Summarytableofthezooplanktonspecies choseninHarpLakebetween
1980-2004usingthedataaftersubstitutingtheblankvalues withthe
lowest detectionlimit (LDL),N=25years……………………………..123
Table2.3: Regressionmodels usingtheabundanceofzooplanktonspecies using
multiplesteps: year(1-25)anddayofyear(Juliandate)……………....124
Table2.4: Spearmancorrelationcoefficients betweentheresidual abundanceof
zooplanktonandthewindfieldusingtheresidual abundancegenerated
from theyear/dayofyearmodels……..………………………………..125
Table2.5: PCAsummaryfrom the17chemistryvariables from HarpLake,Ontario
andthesummaryproportions ofthegreatest variance.………...………126
Table2.6: Summaryofall possibleregression models betweenzooplankton
abundanceandpredictor(s)inHarpLakeduring1980-2004…..……....127
Table2.7: Stepwisemultiplelinearregressionmodels tobetterpredict zooplankton
abundanceinHarpLakeusingchemistry………………………………128
Table2.8: Stepwisemultiplelinearregressionmodels tobetterpredict zooplankton
abundanceinHarpLakeusingwind……………………………………129
Table2.9: Stepwisemultiplelinearregressionmodels tobetterpredict zooplankton
abundanceinHarpLakeusingyear/dayofyearandchemistry………..130
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Table2.10: Spearmancorrelationcoefficients betweentheresidual abundanceof
zooplanktonandthewindfieldusingtheresidual abundancegenerated
from theyear/dayofyearandchemistrymodels…………………..…...131
Table2.11: Stepwisemultiplelinearregressionmodels tobetterpredict zooplankton
abundanceinHarpLakeusingyear/dayofyearandwind……………..132
Table2.12: Stepwisemultiplelinearregressionmodels tobetterpredict zooplankton
abundanceinHarpLakeusingchemistryandwind……………………133
Table2.13: Stepwisemultiplelinearregressionmodels tobetterpredict zooplankton
abundanceinHarpLakeusingyear/dayofyear,chemistryandwind…134
Table2.14ab: AsummaryoftheMLR model breakdownforeachpredictorbased on
eachofthe9models inTable2.13…………….……………………….135
Table2.15: Summarytableofthechemistryvariables inHarpLake,Ontariofrom
1980–2004……………………………………………………………..137
vi
Listof Figures
Figure1.1: Asimplifiedschematicrepresentationofthewatermovement ina
stratifiedlake.………………….…………………………………………51
Figure1.2: BathymetricmapofHarpLake,Ontario………………………………...52
Figure1.3: Thedailywindspeeds from HarpLakeandMuskokaAirport between
2003-2004……………………..…………………………………………53
Figure1.4: Themonthlywindspeeds from Paint LakeandMuskokaAirport between
1990-2004……………………..…………………………………………54
Figure1.5: BathymetricmapofHarpLake,Ontariowithanoverlayofastandard
compass rosediagram inthedirectionoftrueNorth………….…………55
Figure1.6: Long-term trends inaverageannual windspeedforall months combined
from 1980-2004at theMuskokaAirport,Ontario,Canada…………...…56
Figure1.7: Summaryofwinterwindfields (NovembertoMarch)from 1980-2004
overMuskokaAirport.…………………………………………………...57
Figure1.8: Summaryofice-freewindfields (April toOctober)from 1980-2004over
MuskokaAirport…………………………………………………………58
Figure1.9ab: Long-term trends inaveragemonthlywindspeedfrom 1980-2004at the
MuskokaAirport,Ontario,Canada………………………………………59
Figure1.10: Roseplot depictingtheaverageyearlywinddirection(degrees)forall
months combinedfrom 1980-2004at theMuskokaAirport,Ontario,
Canada…………………………………………………………………....61
Figure1.11ab: Roseplots depictingtheaverageyearlywinddirection(degrees)foreach
monthfrom 1980-2004at theMuskokaAirport,Ontario……….……….62
Figure1.12: Thelong-term trends inaverageannual abundanceoftheselected
zooplanktonspecies inHarpLake,Ontario……………………...………64
Figure1.13: Thepresence/absenceofBythotrephes inHarpLake,Ontariobetween
1980-2004………………………………………………………………..65
Figure1.14: Thelong-term trends inaverageannual abundanceas afunctionofthe
averagesurfacetemperatureoftheselectedzooplanktonspecies inHarp
Lake,Ontario……….…………………………………….……………...66
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Figure1.15: TheaverageaveragesurfacetemperatureinHarpLake,Ontariofrom
1980-2004……..……………………..…………………………………..67
Figure1.16ab: Least squares regressionmodels predictingtheaverageannual abundance
oftheselectedzooplanktonspecies abundancewithrespect totheaverage
surfacetemperatureinHarpLake,Ontario………………………………68
Figure1.17: Thelong-term trends inabundanceas afunctionoftheannual averageof
days sinceicefreeoftheselectedzooplanktonspecies inHarpLake,
Ontario………………………………………………………………..….70
Figure1.18ab: Least squares regressionmodels predictingtheaverageannual abundance
oftheselectedzooplanktonspecies abundancewithrespect days sinceice-
free…………………………………………………………………….…71
Figure1.19ab:Least squares regressionmodels predictingtheaverageannual abundance
oftheselectedzooplanktonspecies usingvarious scales: Bythotrephes
(presence/absence),averagesurfacetemperature, anddays sinceice-
free……………………………………………………………………….73
Figure1.20: Aschematicrepresentationofthestratum locations oftheselected
zooplanktonspecies inHarpLake……………………………………….75
Figure1.21: Plots demonstratingtheassociationbetweentheresidual abundanceofD.
mendotaewithwinddirectionfrom 1980-2004overHarpLake.……….76
Figure2.1: Hypothetical winddynamics inHarpLake–Anegativerelationship
betweenabundanceandthepredictorwindspeed……………..……….138
Figure2.2: Hypothetical winddynamics inHarpLake–Apositiverelationship
betweenabundanceandthepredictorwindspeed………………..…….139
Figure2.3: Hypothetical HarpLakeabundancedynamics without wind…………..140
Figure2.4: Flowchart ofthedecisionmakingforthemultipleregressionmodels in
orderto betterpredict zooplanktonabundanceinHarpLake,Ontariousing
year/dayofyear,chemistryandwind…………………………………..141
Figure2.5: Long-term patterns inthechosenzooplanktonspecies inHarpLake,
Ontariobetween1980-2004………………………...…………………..142
Figure2.6: Long-term patterns inthechosenzooplanktonspecies inHarpLake,
Ontariobetween1980-1992(pre-Bythotrephes presence)…………..…143
viii
Figure2.7: Long-term patterns inthechosenzooplanktonspecies inHarpLake,
Ontariobetween 1993-2004(post-Bythotrephes presence)………..…...144
Figure2.8: Long-term patterns inthechosenzooplanktonaccordingtodayofyear
(DOY)inHarpLake,Ontariobetween1980-2004……………..……...145
Figure2.9abc: Regressionmodels usingtheabundanceofzooplanktonspecies using
multiplesteps: year(1-25)anddayofyear(Juliandate)…….………...146
ix
Listof Appendices
Appendix 1: Treatingmissingdatainthezooplanktonabundancedataset……….….156
Appendix 2: Howtoidentifyanassociationbetweenresidual abundanceandthewind
directionusingannual averages (Chapter1)………………………....…166
Appendix 3: Howtoidentifyanassociationbetweenresidual abundanceandthewind
directionusingdailydata(Chapter2)…………………………………..169
Appendix 4: Windfieldcorrelations…………………………………………………172
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Description:epiphanies. Especially, I would like to thank Joe who remained by my side whenever I felt like giving up or needed to hear the right thing to motivate me! Most of all, I would like to dedicate my .. Changes in zooplankton and the phenology of the spiny water flea,. Bythotrephes. Canadian Journal of
