B24A-0305 A Glacial-Interglacial Record of the North Paci6ic … · 2016. 2. 22. · L p N - c i th...
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5.0 4.5 4.0 3.5 3.0 Benthic δ 18 O (‰) Juan de Fuca Ridge 05PC Biological Pump Warmer Cooler Interglacial Glacial MIS 1 MIS 2 MIS 3 MIS 4 MIS 5 MIS 6 MIS 7 MIS 8 MIS 9 MIS 10 MIS 11 MIS 12 MIS 13 MIS 14 MIS 15 MIS 1 MIS 2 MIS 3 MIS 4 MIS 5 MIS 6 MIS 7 MIS 8 MIS 9 MIS 10 MIS 11 MIS 12 MIS 13 MIS 14 MIS 15 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 δ 13 C (‰) Planktonic Benthic -2.0 -1.5 -1.0 -0.5 δ 13 C (‰), Benthic - NpL Mean Interglacial Mean Glacial Strong Weak Strength of Biological Pump 0 50 100 150 200 250 300 350 400 450 500 550 600 Age (ka) 15 10 5 0 C org Flux (mg/cm 2 /kyr) Moving Average Uvigerina spp. Planulina wuellerstorfi, adjusted +0.55‰ N. pachyderma, sinistral Planulina wuellerstorfi Uvigerina spp. 44˚30’ 44˚40’ 44˚50’ 45˚00’ 45˚10’ 131˚ 130˚20’ 130˚ 130˚40’ 39BB 38PC 35PC 12PC 05PC 09PC 20PC 2520 2610 2700 2790 2880 Water Depth (m) The Carbon Pump A Glacial-Interglacial Record of the North Paci6ic Biological Pump for the Past 600,000 Years Tianjia Liu 1 ([email protected]), Jerry F. McManus 1,2 ([email protected]), Kassandra M. Costa 1,2 ([email protected]), and Tanzhuo Liu 2 ([email protected]) 1 Department of Earth and Environmental Sciences, Columbia University, New York, NY 2 Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY +δ 13 C (more enriched) -δ 13 C (more depleted) Atmosphere Deep Ocean Depth Ca 2+ + HCO 3 2- è CaCO 3 + H 2 O + CO 2 CO 2 + H 2 O è CH 2 O + O 2 Surface Ocean CO 2 CO 2 CO 2 CO 2 Gas Exchange Carbonate Pump CH 2 O + O 2 è CO 2 + H 2 O Respiration Photosynthesis Introduction Key Questions Conclusions Results Methods Acknowledgements • The North PaciWic deep ocean is a prime location for carbon sequestration and storage. • No deep water source • No strong upwelling • Through photosynthesis and gas exchange, the surface ocean sequesters CO 2 from the atmosphere, and its biological pump subsequently buries the carbon in the deep ocean. • δ 13 C is a proxy for marine productivity based on the preferential utilization of the lighter 12 C for photosynthesis and reintroduction of 12 C into seawater during respiration. • Organic carbon, or organic matter that fails to decompose, accumulates on the seaWloor, and is subsequently preserved in sediments. (1) Does the North PaciWic foraminiferal record at Juan de Fuca Ridge show that the surface ocean is more 13 C-enriched (photosynthesis-dominated) and deep ocean, 13 C-depleted (respiration-dominated)? And how does the difference in δ 13 C between benthic and planktonic foraminifera change with respect to glacial-interglacial cycles? (2) How does the C org Wlux record at the same location change with respect to glacial-interglacial cycles? (3) How successful are the aforementioned proxies at reWlecting changes in the biological pump with respect to glacial-interglacial cycles? Benthic foraminifera Uvigerina peregrina (left) and Planulina wuellerstor2i (right) Planktonic Foraminifera Neogloboquadrina pachyderma, sinistral (1) The AT-26-19-05 piston core from Juan de Fuca Ridge was sampled at 4 cm intervals. The samples were washed in sieves to separate the coarse (>63 μm) and Wine (<63 μm) fractions. (2) Three species of foraminifera (Uvigerina spp., Planulina wuellerstor2i, and N. pachyderma, sinistral) were picked and analyzed for δ 18 O and δ 13 C by mass spectrometry. (3) The remaining total sediment fractions were decalciWied with concentrated HCl, which then, after left overnight, was diluted with de-ionized water and removed from the samples. The samples were freeze-dried and prepared for C org analysis by mass spectrometry. Sampling Washing Picking Loading Future Work Figure 3. • Photosynthesis removes CO 2 from the atmosphere and enriches surface waters in 13 C. • Respiration and CaCO 3 formation depletes the ocean by releasing 12 C into surrounding waters. • The δ 13 C proWile in the ocean with respect to depth is shown on the left. • CaCO 3 shells from the open water eventually settle on the seaWloor and are preserved in the sediment. Glacials have a strong biological pump. Interglacials have a weak biological pump. Complications for Interpreting δ 13 C and C org 2lux as Proxies for Biological Productivity: (1) Depending on the strength of ocean circulation, the age of the North PaciWic deep water is variable, and therefore, the time that allows respiration to reintroduce 12 C in the deep ocean. (2) During glacials, the entire ocean negatively shifts ~0.3‰ in δ 13 C from terrestrial carbon input, but taking the difference in δ 13 C of benthics and NpL eliminates these potential errors of absolute productivity for either surface or deep ocean. (3) Unlike that of deep water, which is derived from other sources and not in contact with the atmosphere, the isotopic composition of surface water may be more susceptible to air-sea interaction and regional climate changes. (1) Because photosynthesis enriches the surface water in 13 C and respiration depletes the deep water in 13 C, the difference in δ 13 C fractionation between benthic and planktonic characterizes the biological pump . (2) The North PaciWic biological pump is relatively strong during glacials and weak during interglacials. (3) Variations in the organic carbon 6lux support the weak biological pump -interglacial, strong biological pump -glacial conclusion. (4) However, factors, such as regional climate changes, aging of the North PaciWic deep water, and air-sea interaction, can complicate proxy interpretation. (1) The MIS 11 enigma : What caused the δ 13 C fractionation to suggest an abnormally strong biological pump, yet C org Wlux a weak biological pump at ~400ka (circled on Fig. 4) ? Why did the δ 13 C of NpL become very enriched, when the δ 13 C of benthic species was relatively stable? (2) More Data : Proxies, such as opal, and records from other cores are needed to reWine and corroborate conclusions on the biological pump reconstruction. Funding was provided by the Earth Institute and National Science Foundation. Special thanks to Kelly Luis, Anna LoPresti, and Christy Jenkins for their help, dedication, and work on the SeaVOICE project, and Dr. Wei Huang for stable isotope and organic carbon measurements. Figure 1. As seen in the Vostok ice core record, changes in solar insolation drove glacial-interglacial cycles, during which atmospheric CO 2 varied, with low CO 2 during glacials and high CO 2 during interglacials (Petit et al., 1999). References Lisieski, L. E. and M.E. Raymo. (2005). A Pliocene-Pleistocene stack of 57 globally distributed benthic δ 18 O records. Paleoceanography, 20 (PA1003). Petit, J.R. et al. (1999). Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature, 399 (429-436). Juan de Fuca Ridge Site Map Figure 2. Tectonically spreading, Juan de Fuca Ridge is an active underwater volcanic mountain range in the North PaciWic off Washington state coast, as shown on the right. The location of JdFR piston cores (PC) are shown on the left. 05PC (circled in red), farthest from the Juan de Fuca Ridge (light gray band), was analyzed for this study. Source: NOAA Organic Carbon Pump SEDIMENT Figure 4. The strength of the biological pump is characterized by two proxies: 1) the difference in δ 13 C fractionation between benthic foraminifera and planktonic species N. pachyderma, sinistral; and 2) C org 2lux. (2) C org Wlux is high during glacials, and low during interglacials. It peaks late in deglaciation periods. (1) The difference in δ 13 C between benthic foraminifera (P. wuellerstor2i adjusted -0.735‰) and NpL is relatively large during glacials and small during interglacials. The δ 13 C records of NpL, Planulina wuellerstor2i, and Uvigerina, spp. shows the depletion of δ 13 C with depth in the water column as respiration reintroduces 12 C into the seawater. The difference in δ 13 C between P. wuellerstor2i and NpL represents respiration in the water column, and that between Uvigerina spp. and P. wuellerstor2i represents respiration in the mud. Source: Lutze (1978) Source: Schweizer et al. (2005) Source: T. Struve, IFM-GEOMAR B24A-0305
Transcript of B24A-0305 A Glacial-Interglacial Record of the North Paci6ic … · 2016. 2. 22. · L p N - c i th...
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AGlacial-InterglacialRecordoftheNorthPaci6icBiologicalPumpforthePast600,000Years
TianjiaLiu1([email protected]),JerryF.McManus1,2([email protected]),KassandraM.Costa1,2([email protected]),andTanzhuoLiu2([email protected])1DepartmentofEarthandEnvironmentalSciences,ColumbiaUniversity,NewYork,NY2Lamont-DohertyEarthObservatoryofColumbiaUniversity,Palisades,NY
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Introduction
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Acknowledgements
• TheNorthPaciWicdeepoceanisaprimelocationforcarbonsequestrationandstorage.
• Nodeepwatersource• Nostrongupwelling
• Throughphotosynthesisandgasexchange,thesurfaceoceansequestersCO2fromtheatmosphere,anditsbiologicalpumpsubsequentlyburiesthecarboninthedeepocean.
• δ13Cisaproxyformarineproductivitybasedonthepreferentialutilizationofthelighter12Cforphotosynthesisandreintroductionof12Cintoseawaterduringrespiration.
• Organiccarbon,ororganicmatterthatfailstodecompose,accumulatesontheseaWloor,andissubsequentlypreservedinsediments.
(1)DoestheNorthPaciWicforaminiferalrecordatJuandeFucaRidgeshowthatthesurfaceoceanismore13C-enriched(photosynthesis-dominated)anddeepocean,13C-depleted(respiration-dominated)?Andhowdoesthedifferenceinδ13Cbetweenbenthicandplanktonicforaminiferachangewithrespecttoglacial-interglacialcycles?
(2)HowdoestheCorgWluxrecordatthesamelocationchangewithrespecttoglacial-interglacialcycles?
(3)HowsuccessfularetheaforementionedproxiesatreWlectingchangesinthebiologicalpumpwithrespecttoglacial-interglacialcycles?
BenthicforaminiferaUvigerinaperegrina(left)andPlanulinawuellerstor2i(right)
PlanktonicForaminiferaNeogloboquadrinapachyderma,sinistral
(1)TheAT-26-19-05pistoncorefromJuandeFucaRidgewassampledat4cmintervals.Thesampleswerewashedinsievestoseparatethecoarse(>63μm)andWine(<63μm)fractions.
(2)Threespeciesofforaminifera(Uvigerinaspp.,Planulinawuellerstor2i,andN.pachyderma,sinistral)werepickedandanalyzedforδ18Oandδ13Cbymassspectrometry.
(3)TheremainingtotalsedimentfractionsweredecalciWiedwithconcentratedHCl,whichthen,afterleftovernight,wasdilutedwithde-ionizedwaterandremovedfromthesamples.Thesampleswerefreeze-driedandpreparedforCorganalysisbymassspectrometry.
SamplingWashing
Picking
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Figure3.• PhotosynthesisremovesCO2fromtheatmosphereandenrichessurfacewatersin13C.
• RespirationandCaCO3formationdepletestheoceanbyreleasing12Cintosurroundingwaters.
• Theδ13CproWileintheoceanwithrespecttodepthisshownontheleft.
• CaCO3shellsfromtheopenwatereventuallysettleontheseaWloorandarepreservedinthesediment.
Glacialshaveastrongbiologicalpump.Interglacialshaveaweakbiologicalpump.
ComplicationsforInterpretingδ13CandCorg2luxasProxiesforBiologicalProductivity:
(1)Dependingonthestrengthofoceancirculation,theageoftheNorthPaciWicdeepwaterisvariable,andtherefore,thetimethatallowsrespirationtoreintroduce12Cinthedeepocean.
(2)Duringglacials,theentireoceannegativelyshifts~0.3‰inδ13Cfromterrestrialcarboninput,buttakingthedifferenceinδ13CofbenthicsandNpLeliminatesthesepotentialerrorsofabsoluteproductivityforeithersurfaceordeepocean.
(3)Unlikethatofdeepwater,whichisderivedfromothersourcesandnotincontactwiththeatmosphere,theisotopiccompositionofsurfacewatermaybemoresusceptibletoair-seainteractionandregionalclimatechanges.
(1)Becausephotosynthesisenrichesthesurfacewaterin13Candrespirationdepletesthedeepwaterin13C,thedifferenceinδ13Cfractionationbetweenbenthicandplanktoniccharacterizesthebiologicalpump.
(2)TheNorthPaciWicbiologicalpumpisrelativelystrongduringglacialsandweakduringinterglacials.
(3)Variationsintheorganiccarbon6luxsupporttheweakbiologicalpump-interglacial,strongbiologicalpump-glacialconclusion.
(4)However,factors,suchasregionalclimatechanges,agingoftheNorthPaciWicdeepwater,andair-seainteraction,cancomplicateproxyinterpretation.
(1)TheMIS11enigma:Whatcausedtheδ13Cfractionationtosuggestanabnormallystrongbiologicalpump,yetCorgWluxaweakbiologicalpumpat~400ka(circledonFig.4)?Whydidtheδ13CofNpLbecomeveryenriched,whentheδ13Cofbenthicspecieswasrelativelystable?
(2)MoreData:Proxies,suchasopal,andrecordsfromothercoresareneededtoreWineandcorroborateconclusionsonthebiologicalpumpreconstruction.
FundingwasprovidedbytheEarthInstituteandNationalScienceFoundation.SpecialthankstoKellyLuis,AnnaLoPresti,andChristyJenkinsfortheirhelp,dedication,andworkontheSeaVOICEproject,andDr.WeiHuangforstableisotopeandorganiccarbonmeasurements.
Figure1.AsseenintheVostokicecorerecord,changesinsolarinsolationdroveglacial-interglacialcycles,duringwhichatmosphericCO2varied,withlowCO2duringglacialsandhighCO2duringinterglacials(Petitetal.,1999).
ReferencesLisieski,L.E.andM.E.Raymo.(2005).APliocene-Pleistocenestackof57globallydistributedbenthicδ18Orecords.Paleoceanography,20(PA1003).Petit,J.R.etal.(1999).Climateandatmospherichistoryofthepast420,000yearsfromtheVostokicecore,Antarctica.Nature,399(429-436).
JuandeFucaRidgeSiteMap
Figure2.Tectonicallyspreading,JuandeFucaRidgeisanactiveunderwatervolcanicmountainrangeintheNorthPaciWicoffWashingtonstatecoast,asshownontheright.ThelocationofJdFRpistoncores(PC)areshownontheleft.05PC(circledinred),farthestfromtheJuandeFucaRidge(lightgrayband),wasanalyzedforthisstudy. Source:NOAA
OrganicCarbonPump
SEDIMENT
Figure4.Thestrengthofthebiologicalpumpischaracterizedbytwoproxies:1)thedifferenceinδ13CfractionationbetweenbenthicforaminiferaandplanktonicspeciesN.pachyderma,sinistral;and2)Corg2lux.
(2)CorgWluxishighduringglacials,andlowduringinterglacials.Itpeakslateindeglaciationperiods.
(1)Thedifferenceinδ13Cbetweenbenthicforaminifera(P.wuellerstor2iadjusted-0.735‰)andNpLisrelativelylargeduringglacialsandsmallduringinterglacials.
Theδ13CrecordsofNpL,Planulinawuellerstor2i,andUvigerina,spp.showsthedepletionofδ13Cwithdepthinthewatercolumnasrespirationreintroduces12Cintotheseawater.Thedifferenceinδ13CbetweenP.wuellerstor2iandNpLrepresentsrespirationinthewatercolumn,andthatbetweenUvigerinaspp.andP.wuellerstor2irepresentsrespirationinthemud.
Source:Lutze(1978)
Source:Schweizeretal.(2005)
Source:T.Struve,IFM-GEOMAR
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