The Northern North Atlantic Springer-Verlag Berlin Heidelberg GmbH Priska Schăfer . Will Ritzrau . Michael Schliiter . Jo rn Thiede (Eds.) The Northern North Atlantic A Changing Environment With 243 Figures and 43 rables , Springer EDITORS: Professor Dr. Priska Schiifer Dr. Will Ritzrau University of Kiel St. Ilgener StraBe 2 Institute for Geosciences 69190 Walldorf OlshausenstraBe 40 Germany 24118 Kiel Germany Professor Dr. Michael Schliiter Professor Dr. Jo rn Thiede Alfred Wegener Institute for Alfred Wegener Institute for Polar and Marine Research Polar and Marine Research ColumbusstraBe ColumbusstraBe 27568 Bremerhaven 27568 Bremerhaven Germany Germany ISBN 978-3-642-63136-8 Library of Congress Cataloging-in-Publication Data The northern North Atlantic: a changing environment / Priska Schafer ... [et al.] (eds). p. cm. Includes bibliographical references (p.). ISBN 978-3-642-63136-8 ISBN 978-3-642-56876-3 (eBook) DOI 10.1007/978-3-642-56876-3 1. Oceanography - North Atlantic Ocean. 2. Paleoceanography - North Atlantic Oceao. 3. Climatic changes - North Atlantic Ocean. 1. Schafer, Priska. GC491 N68 2001 551.46'1l-dc21 This work is subject to copyright. Ali rights are reserved, whether the whole or part of the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, aod storage in data baoks. Duplication of this publication or parts thereof is permitted only under the provisions of the Germao Copyright Law of September 9, 1965, in its current version, aod permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. http://www.springer.de © Springer-Verlag Berlin Heidelberg 2001 Originally published by Springer-Verlag Berlin Heidelberg New York in 2001 Softcover reprint of the hardcover I st edition 2001 The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations aod there fore free for general use. Cover-Design: Erich Kirchner, Heidelberg Typesetting: Camera-ready by Julia Braun (Atelier Fischer, Berlin) aod Matthias Steffens SPIN 10721006 32/3130-5 4 3 2 1 O - Printed on acid-free paper Preface ThenorthernNorthAtlanticisthekeyregioninthemodemglobalthermohalinecirculationsystem oftheocean,wellknownasthe"conveyorbelt".IntheGreenland-Iceland-NorwegianSeas,fresh andcolddeepwaterisformed andspreadsoutthroughtheAtlanticintotheworldoceans. Incon trasttotheNorthPacific,temperateandice-coveredsurfacewatersaremeridionallyseparatedby distinctoceanicfronts inthenorthernNorthAtlantic. ThelatitudinalextensionofafairlymildclimateasfarnorthasnorthwesternEuropeistheresult ofthis large-scalehydrography, andofthe oceaniccirculationpattern in the Greenland-Iceland NorwegianSeas.Theintensityofdeep-waterrenewalandits variability notonlycontrolthecli mateofthenorthernhemispherebutalsohaveadirectimpactontheenvironmentalconditionsfor the organisms in the ocean and on the surroundingcontinents. Rapidclimaticchanges,as docu mented in ice cores from Greenland, strongly effect the oceanic circulation pattern and hydro graphyoftheNordicSeasaswellastheexchangeoftheirsurfaceanddeep-watermasseswiththe adjacentoceans. The interdisciplinary research project "Global environmental change: The northern North Atlantic"(SFB313)wasalong-termscientificprogramattheUniversityofKiel,fundedfrom1985 to 1998 by the German Science Foundation, and with additional financial support from the UniversityandtheStateofSchleswig-Holstein.Theprojectfocussedonthetemporalandspatial variabilityofclimaticandenvironmentalchangesinthenorthernNorthAtlanticandtheireffects onthemarineecosystemofthepresentandthepast, as documentedin thecompositionofliving andextantcommunitiesofmarineorganismsanddeep-seasedimentsoftheLateQuaternary. TheSFB 313combinedawidevarietyofdisciplines,suchasmarinebiologyincludingplank tology, benthologyandpolarecology,microbialbiology,bio-andbiogeochemistry,marinegeol ogy andmicropaleontology, paleoceanographyandpaleoclimatology, geophysics andnumerical modelling.Thesedisciplines wereorganizedintotwosubgroups,firstly focussingonthemodem biological,chemicalandsedimentologicalprocessesinthewatercolumnandinthesurfacesedi ments,secondlytryingtodeconvolutetheclimateandenvironmentalhistoryandthedevelopment ofmarinelifeduringtheLateQuaternary. TheoriginalconceptforthescientificprogramoftheSFB313wasaddressedtoprocessescon trollingsedimentationintheNorwegian-GreenlandSeainrealandpasttime,withthespecificaim ofunderstandinghowoceancurrentsandtheirhistoricvariabilityarerecordedinsediments.This wasintendedtobeaccomplishedthroughthedistributionpatternsoftheirterrigenousandbiogenic components at the seafloor (formal title ofthe SFB 313 in German: "Sedimentation im Euro paischenNordmeer:AbbildungundGeschichtederozeanischenZirkulation")TheSFB waspre ceded by a pilotphase to evaluate the existence ofsuitable areas with undisturbed sedimentre cords.Thiswaseasilyachievedbyhighresolutionseismicreflectionprofiling. From 1985 to 1990,the SFB 313 hadastrongregionalfocus ontheNorwegian Seaincluding theVlIlringPlateauandtheBarentsShelfslope.Theprogramwasdirectedtowardsthreekeyissues, namely(1)toreconstructthepaleoceanographichistoryofthemaincurrentsystemsoftheNorwe gian-GreenlandSea,(2)tounderstandthebiological,chemical,andphysicalprocesseswhichresult in theformation ofsedimentparticles and sedimentfluxes from the watercolumntothe seafloor, and(3)toinvestigatetheshort-andlong-termvariabilityofthisoceanographicsystem. Duringitssecondhalf, theSFB 313 extendeditsfocus onglobalphenomenausing datafrom theNorwegian-GreenlandSeatoexemplifypropertiesoftheglobalenvironment.Whilecontinuing to investigatethe modemprocesses, paleoceanographic studieswere restricted to the last two to threeclimaticcycles.Inthislatterpart,newsubtasksaddressedthehistoryofpelagicbiota(under the acronym SYNPAL), and a major effort was launched to model ancient paleoceanographic scenarios.AdominantproportionoftheexpeditionsduringthisphasevisitedtheregionsoffGreen land,establishingadatabaseoftheArcticandpolarwatermasses. VI Preface Thechaptersofthisbooksummarizetheresultsof14yearsofinterdisciplinaryresearch. Spe cificemphasisislaidonthesynopticresumeoftheresultsofvariousscientificsubprojectsofthe SFB.Therefore,mostchaptershavenumerousauthors whowereinvolvedduring variousphases oftheSFB. The scientificresults strongly benefitedfrom ongoing international cooperation,in particular withNorway,France,Canada,GreatBritain,andtheIMAGES/PAGEScommunity.Therefore,it isgreatlyappreciatedthatanumberofcontributionsinthis volumecomefrom colleagues(Rene Ramseier,CarenGarrityandThomasMartin,TomNoji,LisaMiller,IngunnSkjelvan,EvaFalck, YngveB0rsheim,FranciscoRey,JuanitaUrban-RichandTrulsJohannessen,TjeerdvanWeering, AntoniRosell-Mele,MortenHald,WilliamPeltier,andKatoroSakai)withwhomtheSFBhashad scientificexchangeformanyyears. Toguarantee an international standard, each chapterwas reviewed independently by two col leagueswithstronginternationalreputationintheirfieldofscience.Wethereforeexpressourthanks to the following colleagues: Andrea Abelmann, Bremerhaven; Alexander Altenbach, MUnchen; UlrichBathmann,Bremerhaven;AngeloCamerlenghi,Trieste; GeraldDickens,Townsville; Ger hardFischer,Bremen;JohnGage,Oban;RUdigerGerdes,Bremerhaven;JoanGrimalt,Barcelona; Morten Hald, Troms0; Christoph Hemleben, TUbingen; Richard Jahnke, Savannah; Michael Ka minski, London; Nalan Ko~, Bergen; Jan Laberg, Troms0; Richard Lampitt, Southampton; Gerd Liebezeit,Wilhelmshaven; OliverMarchal,Bern; LawrenceMayer,Walpole;Jack1. Middleburg, Yerseke;UweMikolajewicz,Hamburg;PeterMinnett,Miami;PeterMUller,Bremen;ThomasNoji, Bergen;EikeRachor,Bremerhaven;RichardSternberg,Seattle;KlausStruebing,Hamburg;Kozo Takahashi,Fukuoka;PaulTreguer,Brest;AnnedeVernal, Montreal;ToreVorren,Troms0;Jtirgen Willebrand,Kiel;RainerZahn,Kiel. We are grateful to Jayne Wolf-Welling and Ortrud Runze for their assistance in editing the Englishofthemanuscripts.Theyalsoguaranteedconsistencyofscientificterms,formulationsand abbreviations usedbythedifferentauthors. Specialthanks areduetoMatthiasSteffensandJulia Braunfortheirmeticulouscareintheintegrationofchaptersandfigures submittedinvariousfor mats,andalsotheirassistancewiththeeditorialwork.Theircloseco-operation,timeanddiligent effortsthroughoutthepreparationofthisvolumewereverymuchappreciatedbytheEditors. The SFB thanks the German Science Foundation, the University of Kiel, and the State of Schleswig-Holsteinfor theirfinancial supportandconstantattention throughout the years. Over thepast14years,alargenumberofseagoingexpeditionswereundertakenintotheGreenland-ice land-NorwegianSeas.ThegreatsuccessoftheSFBistoalargeextentdependentontheskillsand thecontinualsupportbythemastersandcrewsofallresearchvesselsinvolved,andbytheexcel lentcooperationwiththeassociatedlogisticorganizations.Finally,wethankthepublishinghouse Springerfortheirsupportduringthepreparationofthisbook. Kiel,January2001 P. Schafer,Kiel W. Ritzrau,Walldorf M. SchlUter,Kiel J.Thiede,Bremerhaven Contents P. Schafer, J. Thiede, S. Gerlach, G. Graf, E. SuessandB. Zeitzschel TheEnvironmentoftheNorthernNorth-AtlanticOcean: ModernDepositional ProcessesandtheirHistoricalDocumentation ............................................... 1 R. O. Ramseier, C. GarrityandT. Martin AnOverviewofSea-IceConditionsintheGreenlandSeaandtheRelationship ofOceanicSedimentationtotheIceRegime 19 T. T. Noji, L.A. Miller, I. Skjelvan, E. Falck, K. Y. B¢rsheim, FRey, J. Urban-RichandT. Johannessen ConstraintsonCarbonDrawdownandExportintheGreenlandSea .................... 39 R. Peinert,A.Antia, E. Baueifeind, B. vonBodungen, O. Haupt, M. Krumbholz, I. Peeken, R. O. Ramseier, M. VossandB. Zeitzschel ParticleFluxVariabilityinthePolarandAtlanticBiogeochemicalProvinces oftheNordicSeas. ...................................................................... 53 R. Peinert, E. Baueifeind, R. Gradinger, O. Haupt, M. Krumbholz, I. Peeken, I. WernerandB. Zeitzschel BiogenicParticleSourcesandVerticalFluxPatternsintheSeasonally Ice-CoveredGreenlandSea 69 A. Schroder-Ritzrau, H. Andruleit, S. Jensen, C. Samtleben, P. Schafer, 1. Matthiessen, H. C. Hass, A. KohlyandJ. Thiede Distribution,ExportandAlterationofFossilizablePlanktonintheNordicSeas .................. 81 1. Matthiessen, K. -H. Baumann,A. Schroder-Ritzrau, C. Hass, H. Andruleit, A. Baumann, S. Jensen, A. Kohly, U. Pfiaumann, C. Samtleben, P. SchaferandJ. Thiede DistributionofCalcareous,SiliceousandOrganic-WalledPlankticMicrofossils inSurfaceSedimentsoftheNordicSeasandtheirRelationtoSurface-WaterMasses 105 L. ThomsenandT. vanWeering ParticleTransport,DistributionPatternsofSedimentological PropertiesandBiologicalCommunities 129 H. Fohrmann, J. O. Backhaus, F Blaume, B. J. Haupt, J. Kampf, K. Michels, 1. Mienert, 1. Posewang, W Ritzrau, J. Rumohr, M. WeberandR. Woodgate ModernOceanCurrent-ControlledSedimentTransportinthe Greenland-Iceland-Norwegian(GIN)Seas 135 J. Rumohr, F Blaume, H. Erlenkeuser, H. Fohrmann, F -1. Hollender, J. MienertandC. Schafer-Neth RecordsandProcessesofNear-BottomSedimentTransportalongthe Norwegian-GreenlandSeaMarginsduringHolocene andLateWeichselian(TerminationI)Times 155 D. Piepenburg, A. Brandt, K. vonJuterzenka, M. Mayer, K. Schnack, D. Seiler, U. WitteandM. Spindler PatternsandDeterminantsoftheDistributionandStructureof BenthicFaunalAssemblagesintheNorthernNorthAtlantic 179 VIII Contents l¥.Ritzrau, G. GrafandM. SchlUter ExchangeProcessesacrosstheSedimentWaterInterface ... .................................. 199 l¥. Ritzrau, G. Graf,A. Scheltzandl¥. Queisser Bentho-PelagicCouplingandCarbonDynamicsintheNorthernNorthAtlantic 207 M. SchlUter, E. J. Sauter, D. Schulz-Bull, l¥.BalzerandE. Suess FluxesofOrganicCarbonandBiogenicSilicaReachingtheSeafloor: AComparisonofHighNorthernandSouthernLatitudesoftheAtlanticOcean 225 M. KosterandL. -A. Meyer-Rei! ConcentrationandMicrobialDecompositionofOrganicMaterialin SedimentsoftheNorwegian-GreenlandSea 241 J. Mienert, J. PosewangandD. Lukas ChangesintheHydrateStabilityZoneontheNorwegianMargin andtheirConsequenceforMethaneandCarbonReleasesIntotheOceanosphere 259 M. Hald ClimateChangeandPaleoceanography 281 H. C. Hass, H. Andruleit,A. Baumann, K. -H. Baumann,A. Kohly, S. Jensen, J. Matthiessen, C. Samtieben, P. Schafer, A. Schroder-RitzrauandJ. Thiede ThePotentialofSynopticPlanktonAnalysesforPaleoclimaticInvestigations: FivePlanktonGroupsfrom theHoloceneNordicSeas 291 M. Weinelt, l¥. Kuhnt, M. Sarnthein, A.Altenbach, O. Costello, H. Erlenkeuser, U. Pflaumann, J. Simstich, U. Struck,A. Thies, M. H. TrauthandE. Vogelsang PaleoceanographicProxiesintheNorthernNorthAtlantic 319 A. Rosell-Melt ExaminationoftheUseofBiomarkerProxiesfortheReconstruction ofPaleoceanographicConditionsintheNorthernNorthAtlantic 353 M. Sarnthein, K. Stattegger, D. Dreger, H. Erlenkeuser, P. Grootes, B. J. Haupt, S. Jung, T. Kiefer, l¥. Kuhnt, U. Pflaumann, C. Schafer-Neth, H. Schulz, M. Schulz, D. Seidov, 1. Simstich, S. vanKreveld, E. Vogelsang, A. VolkerandM. Weinelt FundamentalModesandAbruptChangesinNorthAtlanticCirculationand Climateoverthelast60ky-Concepts,ReconstructionandNumericalModeling 365 H. A. Bauch, U. StruckandJ. Thiede PlankticandBenthicForaminiferaasIndicatorsofPastOceanChangesin SurfaceandDeepWatersoftheNordicSeas 411 l¥.R. PeltierandK. Sakai Dansgaard-OeschgerOscillations:AHydrodynamicTheory 423 c. Schafer-NethandA. Paul CirculationoftheGlacialAtlantic:ASynthesisofGlobalandRegionalModeling 441 J. Thiede, P. Schafer, l¥.Ritzrau, M. Schliiter, A. Schroder-Ritzrau andMembersofSFB313 PresentandPastOceanographicControlsofSedimentFormationinthe NorthAtlantic-ArcticGateway(ACriticalAppraisalofSFB313ScientificResults) 463 The Environment ofthe Northern North-Atlantic Ocean: Modern Depositional Processes and their Historical Documentation PriskaSchafer!, JornThiede2,3, SebastianGerlach4, Gerd GraP, Erwin Suess2and BerntZeitzsche14 1InstituteforGeosciences, KielUniversity,Olshausenstrasse40,24118Kiel, Germany 2GEOMAR, ResearchCenterforMarineGeosciences,KielUniversity,Wischhofstrasse 1-3, 24148Kiel, Germany 3AlfredWegenerInstituteforPolarandMarineResearch,Columbusstrasse,27568Bremerhaven, Germany 4InstituteforMarineResearch, KielUniversity,DtisternbrookerWeg 20, 24105 Kiel, Germany 5InstituteforBiology,RostockUniversity,Freiligrathstrasse7-8,18055Rostock, Germany Introduction chapters in thisbookarepartofsuchaspecializedre searchproject("SonderforschungsbereichSFB") with Humanitytodayislivinginafast-changingworld.Our long-term funding (1985-1998) from the Deutsche future depends onourability to use theplanetand its Forschungsgemeinschaft (DFG) and the Christian naturalresourceswithoutdestroyingthem,andtoadapt Albrechts-University,Kiel. Thedeepseafloordeposits to changesin the global environmentin the very near oftheNordicSeas(Greenland-Iceland-NorwegianSeas) future. Thiscanonlybe achieved through an intimate display a wide variety ofcompositions. Therefore, by understanding ofthe modem and past environments, comparison with the modem pelagic/benthic environ andtherebyitspotentialforchange,especiallywithre ment, theysupplycluestomajorchangesinthemarine specttobasicrates ofchange, andtoessentialproper environmentinthegeologicpast,thepresentandprob tiesoftheenvironment. ablythenearfuture. There are a few tools available for ascertaining a TheNordicSeas(Fig.1and2)holdakeypositionin scientifically-based estimate of future environmental the temporal variability of the environment, both in change.Manyoftheseassessmentsarebasedonefforts small-scale (seasonal to interannual) and large-scale tomodelthepropertiesoftheatmosphereoroceans,the (decadal to millennial) time intervals. As an important resultsofwhichmaythenbeverifiedonlyinthefuture, centerofdeep-waterformation, the northern NorthAt for example, the documentation of the onset of the lantic Ocean provides a driving force for the global "greenhouseeffect"inthe 1980'sorsea-levelchanges. oceaniccirculationsystem, termedthe"conveyorbelt" Geological data obtained from the composition and (Stommel 1961; Rooth 1982; Broecker and Denton propertiesofmarinesediments,iceshields,orlakesed 1989;BroeckerandPeng1989).Today,theNordicSeas iments,providerecordsofpastenvironmentalchanges areamarginaloceancharacterizedbyananti-estuarine overawidevarietyoftime-scales. Suchsedimentand circulationpattern(Seidovetal. 1996).Thetransportof icecompositiondatadonotreflecttheentireglobalen relatively warmsurfacewaterfrom thecentralAtlantic vironment, but only distinct characteristic elements. into theNordicSeas, andtheformation andoutflowof However, temporal and spatial changes oftheir prop oceanicdeepwaterthroughreleaseofthermalenergyto ertiescanoffercluestohistoricalchangesoftheglobal the atmosphere has direct control over the climate in environmentwhichmaysuggestthenature,range,and northwesternEurope(Broecker1991;Veumetal.1992). paceoffuture environmentalchanges. Amajorscientificconcernhasdealtwiththequestionof When studying global changes, we have to select whether or not this modem anti-estuarine circulation specificareasandtoolstocharacterizedistinctelements pattern had been constant throughout the last glacial oftheenvironment.Thescientistspresentingthevarious interglacialclimaticcycles(Labeyrieetal. 1987).Ithas FromTheNorthernNorthAtlantic:AChangingEnvironment,editedbyP.Schafer,W.Ritzrau,M.Schluter,andJ.Thiede,pp.1-17, Springer,Berlin,2001 2 Schaferetal. O· 75· 70· 40·W 20· O· 20· 40·E 40·~ 20· O· 20· 40·E Fig.!:CirculationofoceanicsurfacewatermassesintheNorwegian-GreenlandseaandadjacentNorthAtlantic,includingseasonal variation ofthe iceedge.- - - - - =iceedgein September;---=iceedgein February; EGC=EastGreenlandCurrent; ESC =East Spitzbergen Current; NAD =NorthAtlantic Drift; NC =Norwegian Current; NCC =Norwegian Coastal Current; = = NKC NorthCapeCurrentandWSC WestSpitzbergenCurrent Fig.2:ResearchareascoveredbytheSFB313.BSS=BarentsSeaslope;DKS=DenmarkStrait;GS=GreenlandSea;RHP=Rockall = = Plateau;andVP Vs>lringPlateau;P Polynya becomeevidentduringthelastfewyearsthatthiscircu NordicSeaspresentenvironmentalstatesthat-inanuni lation system is unstable over short (Lamb 1979; formitarian approach-potentially may provide models Dicksonetal.1988),andlongertimespans(Duplessyet for past climatic scenarios, e.g., the Greenland conti al. 1988;Sarntheinetal. 1994).AccordingtoSarnthein nentalmarginasamodelrepresentingtheeasternpartof etal. (1994,1995),deep-waterformation intheNordic theNorwegianSeaduringthelastglacialinterval. Seasceasedfor shortperiods atthe endofthe lastgla Knowledgeaboutmodemprocessesofpelagicand cialperiod.Rapidclimaticchangesattheendofthelast benthic biologic activity, sedimentation, and biogeo glacial interval caused a sudden cooling (Younger chemical flux patternsis an importantprerequisitefor Dryas) that brought ice formation back to northern the interpretation ofenvironmental signals from sedi Europe for several hundred years (Dansgaard et al. ment cores documenting past time intervals. Large 1989).Variationsindeep-waterformationresultnotonly scale environmental changes such as the last glacial indrasticchangesofglobalfluxesofheat,CO2,andnu interglacialcyclecanbedocumentedinsedimentcores trients,butisalsolinkedviacircum-Antarcticupwelling withhigh stratigraphicresolution. Changesofsurface totheSouthernOcean,andthushasamajorinfluenceon water currents, variations in the intensity ofthe con theglobalclimate(StockerandWright 1991;Sarnthein veyor belt, catastrophic melt-water episodes during andAltenbach 1995). glacial terminations, and insolationchangestriggered TheNordic Seas arecharacterizedby watermasses by cyclic orbital changes (Milankovitch parameters) ofdifferent hydrographic regimes, separated by steep are environmental factors which had controlled, and oceanicgradients.Contrastingregimes,suchastheyear still control the biota and their development in the roundice-freeAtlanticDomainoffNorway,andthesea Nordic Seas throughout the Late Quaternary. To un sonally ice-covered Arctic Domain off Greenland, ravel the development of the biota and its coupling whichincludestheMarginalIceZone(MlZ),providean to abiotic environmental factors is one of the major idealsituationfor monitoringbiologicalandbio-/geo goalsoftheSFB313,andlinksittomajorinternational chemicalparametersandtheirseasonalandinter-annual global change projects such as PAGES (Past Global variations.Thetwocontrastingdomainsofthemodem ChangeProject),ortheODP(OceanDrillingProject).