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dc.contributor.advisorHald, Morten
dc.contributor.authorJernas, Patrycja Ewa
dc.date.accessioned2012-12-03T09:57:58Z
dc.date.available2012-12-03T09:57:58Z
dc.date.issued2012-09-13
dc.description.abstractThe main objective of the PhD study was to improve the knowledge about the ecology of the benthic foraminiferal faunas thus increasing the precision of benthic foraminifera as indicators for modern and past Arctic fjord and shelf environments. The investigation of living (stained) benthic foraminifera assemblages in Kongsfjorden (western Svalbard) was performed on inter-annual and seasonal time scale. The fauna was subsequently compared to the environmental conditions including e.g. hydrology, primary productivity as well as the sediment structure, oxygen profiling, pore-water chemistry, in order to identify the driving forces leading to faunal variations. The newly gained knowledge on benthic foraminifera ecology was applied to interpret paleoceanographic changes the past 2000 years recorded in the two marine sediment cores from the Kongsfjorden and Hinlopen Troughs (northern Svalbard). The results show that living benthic foraminiferal faunas in Kongsfjorden are mainly controlled by the food supply from pelagic production which is closely related to the timing and amount of Atlantic Water (AW) inflow in addition to the release of suspended matter from the surrounding glaciers. The strongest response to the high seasonal productivity and related summer intrusions of AW is shown by dominant Nonionellina labradorica. Further, the study shows that benthic foraminifera inhabiting the micro-environments prefer to live in proximity to the bio-irrigation system (burrows, tubes), what allows them to use more extensively the oxygen and labile organic matter storage. The two paleorecords show a distinct faunal signal from AD 1200-1500 attributed to the development of highly productive oceanographic fronts between the Arctic and Atlantic water masses. This period is followed by more severe conditions from AD 1500-1900 corresponding to the Little Ice Age. The observed long term trends indicate the overall gradual reduction in glacial influence and a possible oceanographic warming of the NW Svalbard shelf over the last two millennia.en
dc.description.doctoraltypeph.d.en
dc.description.popularabstractHovedformålet med studiet var: 1) å øke forståelsen om hvordan og hvor raskt små encellede organismer (såkalte foraminiferer) som lever på havbunnen reagerer på klima- og miljøendringer i Arktis, og 2) hvordan denne kunnskapen kan brukes til å bedre forstå klima- og miljøendringer på Svalbard gjennom de siste 2000 år. Studiet er basert på analyser av havbunnsprøver samt målinger av vannmassenes egenskaper i Kongsfjorden og Hinlopenstredet på Svalbard. Resultatene viser at tilstedeværelsen og artsmangfoldigheten av foraminiferene er kontrollert av ulike faktorer gjennom årstidene. De viktigste faktorer er tilgjengelighet på mat, sjøisdekke og påvirkning fra breer, samt innstrømning av forholdsvis varmt og saltholdig vann Atlantisk Vann som har blitt transportert med Golfstrømmen, langs Norskekysten og videre nordover mot Svalbard. Gjennom de siste 2000 år har innstrømning av Atlantisk Vann variert og ført til gjentatte endringer i bl.a. sjøisutbredelse rundt Svalbard.en
dc.description.sponsorshipThe PhD thesis is funded by the Research Council of Norway (contract number 177520/V30). Additional financial support was received from the Norwegian Polar Institute and University of Tromsø.en
dc.descriptionThe papers of this thesis are not available in Munin: <br/>1. Jernas, P., Klitgaard-Kristensen, D., Husum, K., Koç, N., Tverberg, V., Loubere, P., Prins, M and Dijkstra, N.: 'Response of modern Arctic benthic foraminiferal fauna to annual environmental changes; evidence from Kongsfjorden, Svalbard (forthcoming in Marine Micropaleontology). <br/>2. Jernas, P., Klitgaard-Kristensen, D., Husum, K., Wilson, L. and Koç, N.: 'Paleoenvironmental changes of the last two millennia on the western and northern Svalbard shelf' (forthcoming in Boreas). <br/>3. Jernas, P., Husum K., Klitgaard-Kristensen D., Forwick, M. and Koç, N.: 'Seasonal composition of recent benthic foraminifera in surface sediments of Kongsfjorden, Svalbard' (manuscript) <br/>4. Loubere, P., Jacobson, B., Kritgaard-Kristensen, D., Husum, K., Jernas, P. and Richaud, M.: 'The structure of benthic environments and the paleochemical record of foraminifera', Deep Sea Research, Part 1: Oceanographic Research Papers (2011), vol. 58, no. 5:535-545. Available at <a href=http://dx.doi.org/10.1016/j.dsr.2011.02.011>http://dx.doi.org/10.1016/j.dsr.2011.02.011</a>en
dc.identifier.isbn978-82-8236-070-8
dc.identifier.isbn978-82-8236-071-5
dc.identifier.urihttps://hdl.handle.net/10037/4647
dc.identifier.urnURN:NBN:no-uit_munin_4361
dc.language.isoengen
dc.publisherUniversitetet i Tromsøen
dc.publisherUniversity of Tromsøen
dc.rights.accessRightsopenAccess
dc.subject.courseIDDOKTOR-004en
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466en
dc.subjectpaleoceanographyen
dc.subjectbenthic foraminiferaen
dc.subjectSvalbarden
dc.subjectKongsfjordenen
dc.subjectHinlopenen
dc.titleBenthic foraminifera in an Arctic fjord : recent distribution and fauna of the last two millenniaen
dc.typeDoctoral thesisen
dc.typeDoktorgradsavhandlingen


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