Objec&ve
Material&Methods
Results&Discussion
◯YoshiyukiAbe1,NicoleHildebrandt2,KoheiMatsuno1,AtsushiYamaguchi1,BarbaraNiehoff2andToruHirawake11GraduateSchoolofFisheriesScience,HokkaidoUniversity,Japan2AlfredWegenerIns@tute,HelmholtzCentreforPolarandMarineResearch,GermanyE-mail:[email protected]
ME447A-0977Comparisononver&caldistribu&onofpelagiccopepodabundance,biomassandcommunitystructurebetweenAtlan&candPacificsectoroftheArc&cOcean
Greenland
Canada
Canada Basin
Barents Sea
Chukchi Sea
Kara Sea
Ae&deidae Augap&lidae Calanidae Clausocalanidae Euchae&dae
Heterorhabdidae Lucicu&idae Metridinidae Scolecitrichidae Spinocalanidae Tharybidae
0 25 50 75 1000
250500750
1000
0 25 50 75 100Composi&oninabundance(%)
Composi&oninbiomass(%)(C) (D)
Depth(m
)De
pth(m
)
0250500750
100012501500
0250500750
100012501500
0250500750
1000
0 25 50 75 1000 25 50 75 100
(A)FramStrait (B)ChukchiSea
Zooplanktonsamplingwasconductedatonesta&on(78º50’N,1º59’W)during1July2011.Sampleswerecollectedfromfivedepths(1500–1000–500–200–50–0m)byaver&calMul&Nethaul(MN:150µmmesh,0.25m2mouthopening).
Zooplanktonwassampledatonesta&on(73º48’N,159º58’W)during27September2013.Sampleswerecollectedfromfourdepthstrata(1000–500–200–100–0m)byaver&calhaulwithaVer&calMul&plePlanktonSampler(VMPS:62µmmeshsize,0.25m2mouthopening).
・Zooplanktonsampleswereimmediatelypreservedwith5%bufferedformalin.・Ateachsta&on,temperature,salinityanddissolvedoxygenweremeasuredbyCTDcasts.Chlorophylla(Chl.a)wasalsomeasuredwithfluorescencesensor.
・ Inthelandlaboratory,enumera&onfortaxaandspecies/stageiden&fica&onofcopepodsweremadeunderstereomicroscope.・Totallength(TL)wasmeasuredforeachspeciesandstages.CarbonmasseswerethencalculatedfromTLusinglength-massregression(Yamaguchietal.,2002).
・Basedonzooplanktonabundance,clusteranalyses(Bray-Cur&sconnectedwithUPGMA)weremade.・Speciesdiversi&es(H’)werealsocalculatedbasedoncopepodabundance.・Toclarifythedepthdistribu&onofeachspeciesortaxon,depthswhere50%ofthepopula&onresided(50%distributedlayer:D50%,Pennak,1943)werecalculated.Addi&onalcalcula&onsofD25%andD75%werealsomade.
FieldsamplingFramStrait
ChukchiSea
1.Hydrography3.ClusterandNMDSanalysis2.Spa&alchangesinabundance,biomassandcopepoddiversity
5.Composi&on4.Ver&caldistribu&on
Bothcopepodabundanceandbiomasswerehighestat0–50mlayer(3132ind.m-3
and18.6mgCm-3)anddecreasedwithincreasingdepth.Speciesdiversitywaslowinthesurfacelayer(H’=0.70)andhadpeakat200–500mlayer(1.74).
Copepodabundancewashighestat0–50m(518ind.m-3),whilehighbiomasswasoccurredat100–250m(1.3mgCm-3).Speciesdiversitywashigheveninthesurfacelayer,andthehighestvalue(2.27)wasoccurredat100–250m.
• TemperatureintheFramStraitwashigherthanintheChukchiSea(30-1000m).
• SalinityintheChukchiSeawaslowerthanintheFramStrait(0–300m).
• ThedifferencesinhydrographybetweenthetwosectorswerecausedbytheWestSpitsbergenCurrent(WSC)atthesta&onintheFramStraitandtheBeringSeaSummerandWinterWater(BSSWandBSWW)atthesta&onintheChukchiSea.Fig.2.Ver&caldistribu&onoftemperature,salinity,dissolvedoxygenandChl.aintheFramStrait(A)andtheChukchiSea(B).Depthrangesofsamplinglayersareshowninthenumbersintherightcolumns.Notethatdepthscaleisinlog-scale.
Fig.1.Loca&onofsamplingsta&onsintheFramStrait(Atlan&csectoroftheArc&cOcean)andintheChukchiSea(PacificsectoroftheArc&cOcean).
Fig.3.Ver&caldistribu&onofcopepodabundance,biomassandspeciesdiversityindices(H’)basedontheirabundancedataintheFlamstrait(A)andintheChukchiSea(B).
Fig.4.ResultsoftheclusteranalysisbasedonzooplanktonabundanceusingaBray-Cur&ssimilarity(A).Two-dimensionalrepresenta&onofnonmetricmul&-dimensionalscalingplots,wheredistancebetweensamplesispropor&onaltotheirsimilarity(B).Percentagesimilarityisrepresentedbysurroundingcircles.
Fig.5.Ver&caldistribu&onpaoernsofzooplanktonintheFramStrait(A)andintheChukchiSea(B).Foreachspeciesortaxon,uppersolidcirclesindicateabundance(ind.m–2:watercolumn)andloweropencirclesindicate50%distribu&ondepth(D50%).Ver&calbarsindicatedepthrangeswhere25%(D25%)and75%(D75%)ofthepopula&onwasdistributed.
Fig.6.Ver&calchangesinthecomposi&onoffamiliesofcalanoidcopepodsintermsofabundance(A,B)andbiomass(C,D)intheFramStrait(lep)andintheChukchiSea(right)
FramStrait
ChukchiSea
Dataanalyses
Thedistribu&ondepthanddominantspeciesinthetworegionscorrespondedwell:Oithonaspp.(D50%:32–63m),Oncaeaspp.(D50%:319-324m),Microcalanusspp.(D50%:245-542m).Calanusfinmarchicusdistributedintheepipelagiclayer(D50%:49m)intheFramStrait,butwasnotobservedintheChukchiSea.
Despitelargegeographicaldistances,differentsamplinggearanddifferentseasons,thezooplanktoncommuni&esoftheAtlan&candthePacificsectoroftheArc&cOceanweresimilar.Atbothsta&ons,thecommunitycomposi&onchangedsignificantlywithdepth.C.finmarchicus,whichisadvectedwiththeWSC,onlyoccurredinthesurfacelayeroftheAtlan&csector.
・Inabundance,ClausocalanidaeincludingMicrocalanusspp.dominatedinthemesopelagiclayerofbothregions.SpinocalanidaedominatedthebathypelagiclayerintheChukchiSea.
・Forbiomass,thepredominanceofCalanidaeat0–50mintheFramStraitwascausedbyCalanusfinmarchicus.
WewouldliketoexpressoursincerethankstothecaptainsandcrewsoftheR/VMirai(JAMSTEC)andR/VPolarsternandalotofstaffsinAWI.Thisworkwaspar&allyconductedfortheArc&cChallengeforSustainability(ArCS)project.Acknowledgement
1mm
Arc&ccopepods�
Calanus hyperboreus �
Calanus glacialis �
Metridia longa �
TL�
YamaguchiA,WatanabeY,IshidaHetal.(2002)Communityandtrophicstructuresofpelagiccopepodsdowntogreaterdepthsinthewesternsubarc&cPacific(WEST-COSMIC).DeepSeaResI,49:1007–1025.
ReferencesPennak,R.W.(1943)Aneffec&vemethodofdiagrammingdiurnalofzooplanktonorganisms.Ecology,24:405-407.
FramStrait(A_depthrange,m)ChukchiSea(P_depthrange,m)
(B)
Non-metric MDSTransform: Fourth rootResemblance: S17 Bray-Curtis similarity
Similarity78
FourthRootbdecafP_0-100 P_100-250
P_250-500
P_500-1000
A_0-50
A_50-200 A_200-500A_500-1000
A_1000-1500
2D Stress: 0.042DStress:0.04
Non-metric MDSTransform: Fourth rootResemblance: S17 Bray-Curtis similarity
Similarity78
FourthRootbdecafP_0-100 P_100-250
P_250-500
P_500-1000
A_0-50
A_50-200 A_200-500A_500-1000
A_1000-1500
2D Stress: 0.04
Group average
A_0-50
P_0-100
A_50-200
P_100-250
P_250-500
A_200-500
A_500-1000
P_500-1000
A_1000-1500
Variables
100
90
80
70
60
Similarity
Transform: Fourth rootResemblance: S17 Bray-Curtis similarity
FourthRootbdecaf
(A)
Epipelagic Mesopelagic Bathypelahic
Conclusion
Epipelagic
Mesopelagic
Bathypelagic
1500
1250
1000
750
500
250
0
Microcetellanorvegica
Oith
onaatlan0
ca
Oith
onaspp.
Clan
usfinm
archicus
Oith
onasim
ilis
Pseudo
calanu
sspp
.Ca
lanu
sglacialis
Oncaeaspp.
Scolecith
ricellam
inor
Palaeuchaetaglacialis
Metrid
ialong
aMicracalanu
sspp
.Ca
lanu
shyperbo
reus
Heterorhab
dusn
orvegicus
Gaetan
usbrevispinus
Scolecitricho
psispo
laris
Und
inellaoblon
ga
Ae0d
eopsisrostrata
Spinocalan
uslong
icornis
Drepan
opsisbun
gii
Neomormon
illaminor
Spinocalan
uspolaris
Spinocalan
usantarc0cus
Auga
p0lusg
racialis
Gaetan
uste
nuisp
inus
Scap
hocalanu
sbrevicornis
Scap
hocalanu
smag
nus
Spinocalan
uselong
atus
Spinocalan
ushorrid
us
Spinocalan
ussp
p.
Bivalveslarvae
Foraminife
ra
Thysan
oessaspp.
Them
istoab
yssorum
Echino
derm
larvae
Euph
ausia
cea
Oikop
leuraspp.
Them
istolibellula
Eukroh
niaha
mata
Siph
onop
hora
Hydrozoa
Ostrocoda
Cyclocarisgu
ilelm
iPo
lychaeta
Unide
n>fie
dam
phipod
aCten
opho
ra
(A)FramStrait
Depth(m
)
Ind.m–2
100
1000
10000
100000
Epipelagic
Mesopelagic
Oith
onanaup
lii
Calanu
snauplii
Oith
onasim
ilis
Pseudo
calanu
sspp
.Ca
lanu
sglacialis
Microcetellanorvegica
Paraeuchaetaglacialis
Metrid
ialong
aSpinocalan
uspolaris
Heterorhab
dusn
orvegicus
Micracalanu
sspp
.Au
gap0
lusg
racialis
Paraheterorhab
dusc
ompu
ctus
Scolecith
ricellam
inor
Oncaeaspp.
Ae0d
eopsisminor
Spinocalan
usantarc0cus
Gartan
uste
nuisp
inus
Pseudo
auga
p0lusp
olaris
Scap
hocalanu
smag
nus
Scap
hocalanu
sbrevicornis
Lucicu0a
polaris
Calanu
shyperbo
reus
Spinocalan
uselong
atus
Spinocalan
ussp
p.
Neomormon
illaminor
Chiridiellare
ductella
Gaetan
ussp
p.
Spinocalan
uslong
icornis
Spinocalan
ushorrid
us
Oikop
leuraspp.
Aglantha
digita
le
ParasagiFaelegan
sFri0llaria
spp.
Barnaclenauplii
Foraminife
ra
Polychaeta
Limacinahelicina
Eukroh
niaha
mata
Ostrocoda
Cten
opho
ra
Siph
onop
hora
Amph
ipod
a
1000
750
500
250
0
(B)ChukchiSea
Ind.m–2
100
1000
10000
• Theseresultsoncommunityclassifica&onsuggestthatthereweresmallgeographicaldifferencesbetweentheAtlan&candPacificsectorintheArc&cOcean.Ver&callychangingpaoernswererobust.
I
II
III
IV
V
I
II
III
IV
Depth(m
)
-2 -1 0 1 2 3 4 5 6
2
50
100
200
500
1000
2000
5
10
20
27 28 29 30 31 32 33 34 3526 36
Salinity
Temperature(ºC)(A)
Chl.a
T SO2
0 1 2 3 4
Chl.a(mgm3)
2
50
100
200
500
1000
2000
5
10
20
(B)
Dissolvedoxygen(mlL-1)0 2 4 6 8 10
Depth(m
)
PolarSurfacewater
PolarSurfacewater
BSSW
BSWW
WSC
VMPS�
• Thezooplanktoncommunityclusteredintothreegroups.
• Epipelagicgroup:0–200mMesopelagicgroup:100–1000mBathypelagicgroup:500–1500m
Epi
Meso
Bathy
Abundance(ind.m-3)0 500 1000 1500 2000 2500
0250500750100012501500
Depth(m
)
(A)
(B)
H’0 1 2 3
Biomass(mgCm-3)0 5 10 15 20
02505007501000
–Dominantspecies
Bathypelagic
・ThedominanceofCalanidaeintheotherlayerswasduetoC.hyperboreuswhichdistributedoverwidedepthandgeographicalranges.
Sampleanalyses
MN�
Recently,agreatreduc&onofseaicecoveragehasbeenreportedfortheArc&cOceanduringsummer.Thereduc&onhasbeen reportedtobegreaterforregionswhichconnecttheArc&cwiththeAtlan&candthePacificOcean,respec&vely. Sincethepelagic
faunadiffersbetweentheAtlan&candthePacificOcean,theeffectsofseaicelossonthespeciesand,thus,theArc&cecosystemsareexpectedtobedifferent. However,lioleinforma&onisavailableonthedifferencesinpelagiccommunitybetweentheAtlan&candPacificsectorsoftheArc&cOcean.Inthisstudy,weinves&gatedplanktoniccopepodabundance,biomassandcommunitystructureintheAtlan&candPacificsectorsoftheArc&cOcean,andaddresstheirdifferences.
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