Central Arctic Ocean Response to Pleistocene Earth-Orbital Variations

Three central Arctic Ocean sediment cores were sampled for percentage carbonate, number of foraminifera, and texture. These three parameters were used in spectral analyses to test the idea that the ice-covered Arctic Ocean may respond to orbital forcing in a different manner than has been indicated for lower latitude ice-free oceans. The record for two of the cores represents approximately 1 my, and the record for the third, approximately 400,000 yr. The 100,000-yr frequency is well represented in all of the cores. A 40,000-yr frequency may be present, as well. An unexpected 70,000-yr frequency occurs in most of the spectra and may reflect nonlinear sedimentation rates or the combined effect of obliquity and eccentricity. The strong 100,000-yr signal confirms that, in spite of ice feedback, the Arctic Ocean has responded to orbital forcing in much the same manner as have ice-free oceans.

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Testing the synchronicity of Pleistocene biostratigraphic events in the central Arctic – Do we have a consistent biostratigraphic framework?

10.5194/egusphere-egu21-8345 ◽

2021 ◽

Author(s):

Flor Vermassen ◽

Helen K. Coxall ◽

Gabriel West ◽

Matt O'Regan

Keyword(s):

Arctic Ocean ◽

Sediment Cores ◽

Age Determination ◽

The Arctic ◽

Calcareous Nannofossils ◽

Central Arctic Ocean ◽

Eurasian Basin ◽

Future Work ◽

Amerasian Basin

Harsh environmental and taphonomic conditions in the central Arctic Ocean make age-modelling for Quaternary palaeoclimate reconstructions challenging. Pleistocene age models in the Arctic have relied heavily on cyclostratigraphy using lithologic variability tied to relatively poorly calibrated foraminifera biostratigraphic events. Recently, the identification of Pseudoemiliania lacunosa in a sediment core from the Lomonosov Ridge, a coccolithophore that went extinct during marine isotope stage (MIS) 12 (478-424 ka), has been used to delineate glacial-interglacial units back to MIS 14 (~500 ka BP). Here we present a comparative study on how this nannofossil biostratigraphy fits with existing foraminifer biohorizons that are recognised in central Arctic Ocean sediments. A new core from the Alpha Ridge is presented, together with its lithologic variability and down-core compositional changes in planktonic and benthic foraminifera. The core exhibits an interval dominated by Turborotalita egelida, a planktonic foraminifer that is increasingly being adopted as a marker for MIS11 in sediment cores from the Amerasian Basin of the Arctic Ocean. We show that the new age-constraints provided by calcareous nannofossils are difficult to reconcile with the proposed MIS 11 age for the T. egelida horizon. Instead, the emerging litho- and coccolith biostratigraphy implies that Amerasian Basin sediments predating MIS5 are older than the egelida-based age models suggest, i.e. that the T. egelida Zone is older than MIS11. These results expose uncertainties regarding the age determination of glacial-interglacial cycles in the Amerasian basin and point out that future work is required to reconcile the micro- and nannofossil biostratigraphy of the Amerasian and Eurasian basin.

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Pleistocene variations of beryllium isotopes in central Arctic Ocean sediment cores

Global and Planetary Change ◽

10.1016/j.gloplacha.2009.03.024 ◽

2009 ◽

Vol 68 (1-2) ◽

pp. 38-47 ◽

Cited By ~ 22

Author(s):

Emma Sellén ◽

Martin Jakobsson ◽

Martin Frank ◽

Peter W. Kubik

Keyword(s):

Arctic Ocean ◽

Sediment Cores ◽

Central Arctic Ocean ◽

Ocean Sediment ◽

Beryllium Isotopes

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Sediment archives from the Arctic Ocean provide evidence for massive remobilization of permafrost carbon in Siberia during the last glacial termination

10.5194/egusphere-egu2020-18643 ◽

2020 ◽

Author(s):

Jannik Martens ◽

Birgit Wild ◽

Tommaso Tesi ◽

Francesco Muschitiello ◽

Matt O’Regan ◽

...

Keyword(s):

Arctic Ocean ◽

Large Scale ◽

Sediment Cores ◽

The Arctic ◽

Last Deglaciation ◽

Central Arctic Ocean ◽

Last Glacial ◽

The Arctic Ocean ◽

Siberian Shelf ◽

The Last Glacial

Environmental archives and carbon cycle models suggest that climate warming during the last deglaciation (the transition from the last glacial to the Holocene) caused large-scale thaw of Arctic permafrost, followed by the release of previously freeze-locked carbon. In addition to changing oceanic circulation and outgassing of CO2 trapped in the deep glacial ocean, organic carbon (OC) release from thawing permafrost might have contributed to the rise in atmospheric CO2 by 80 ppmv or ~200 Pg C between 17.5 and 11.7 kyr before present (BP). The few Arctic sediment cores to date, however, lack either temporal resolution or reflect only regional catchments, leaving most of the permafrost OC remobilization of the deglaciation unconstrained.Our study explores the flux and fate of OC released from permafrost to the Siberian Arctic Seas during the last deglaciation. The Arctic Ocean is the main recipient of permafrost material delivered by river transport or collapse of coastal permafrost, providing an archive for current and past release of OC from thawing permafrost. We studied isotopes (&#916;14C-OC, &#948;13C-OC) and terrestrial biomarkers (CuO-derived lignin phenols, n-alkanes, n-alkanoic acids) in a number of sediment cores from the Siberian Shelf and Central Arctic Ocean to reconstruct source and fate of OC previously locked in permafrost.The composite record of three cores from the Laptev, East Siberian and Chukchi Seas suggest a combination of OC released by deepening of permafrost active layer in inland Siberia and by thermal collapse of coastal permafrost during the deglaciation. Coastal erosion of permafrost during the deglaciation suggests that sea-level rise and flooding of the Siberian shelf remobilized OC from permafrost deposits that covered the dry shelf areas during the last glacial. A sediment core from the Central Arctic Ocean demonstrates that this occurred in two major pulses; i) during the B&#248;lling-Aller&#248;d (14.7-12.9 kyr BP), but most strongly ii) during the early Holocene (11-7.6 kyr BP). In the early Holocene, flooding of 80% of the Siberian shelf amplified permafrost OC release to the Arctic Ocean, with peak fluxes 10-9 kyr BP one order of magnitude higher than at other times in the Holocene.It is likely that the remobilization of permafrost OC by flooding of the Siberian shelf released climate-significant amounts of dormant OC into active biogeochemical cycling and the atmosphere. Previous studies estimated that a pool of 300-600 Pg OC was held in permafrost covering Arctic Ocean shelves during the last glacial maximum; one can only speculate about its whereabouts after the deglaciation. Present und future reconstructions of historical remobilization of permafrost OC will help to understand how important permafrost thawing is to large-scale carbon cycling.

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Cyclicity in the middle Eocene central Arctic Ocean sediment record: Orbital forcing and environmental response

Paleoceanography ◽

10.1029/2007pa001487 ◽

2008 ◽

Vol 23 (1) ◽

pp. n/a-n/a ◽

Cited By ~ 24

Author(s):

Francesca Sangiorgi ◽

Els E. van Soelen ◽

David J. A. Spofforth ◽

Heiko Pälike ◽

Catherine E. Stickley ◽

...

Keyword(s):

Arctic Ocean ◽

Middle Eocene ◽

Orbital Forcing ◽

Environmental Response ◽

Sediment Record ◽

Central Arctic Ocean ◽

Ocean Sediment

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New paleomagnetic data on marine sediments from the Central Arctic Ocean

10.5194/egusphere-egu2020-21920 ◽

2020 ◽

Author(s):

Daria Elkina ◽

Thomas Frederichs ◽

Walter Geibert ◽

Jens Matthiessen ◽

Frank Niessen ◽

...

Keyword(s):

Arctic Ocean ◽

Marine Sediments ◽

Sediment Cores ◽

Environmental Research ◽

The Arctic ◽

Lomonosov Ridge ◽

State University ◽

Central Arctic Ocean ◽

Great Debate ◽

The Arctic Ocean

Accurate dating of marine sediments from the Arctic Ocean remains a subject of great debate over the last decades. Due to the lack of adequate materials for biostratigraphy and stable isotope analyses, paleomagnetic reconstructions came into play here but though yielded ambiguous interpretations. Moreover, sedimentation rates in the Quaternary, determined for isolated morphological features in the Arctic Ocean, are often applied to the entire Arctic Ocean realm resulting in an inappropriate oversimplification of probably diverging regional depositional regimes.Paleomagnetic studies on four long sediment cores, collected from the Mendeleev Ridge and the Lomonosov Ridge, complemented by the results from one core from the Podvodnikov Basin, have provided an opportunity to compare the sedimentation history of these profound structures in the Arctic Ocean. Cores PS72/396-5 and PS72/410-3 (Mendeleev Ridge), PS87/023-1, PS87/030-1 (Lomonosov Ridge) and PS87/074-3 (Podvodnikov Basin) were retrieved during expeditions of RV Polarstern in 2008, and 2014. Paleomagnetic, rock magnetic and physical properties measurements were carried out at the Center for Geo-Environmental Research and Modeling (GEOMODEL) of the Research Park in St. Petersburg State University, at the University of Bremen, and the Alfred Wegener Institute.According to the results on the Mendeleev Ridge&#8217;s cores, complemented with 230Th excess study on core PS72/396-5, the Brunhes Matuyama boundary (0.78 Ma) is observed at the first meters below the seafloor. That, together with the Matuyama Gauss transition (2.58 Ma) recorded in both cores, implies the mean sedimentation rate in this area to be in the order of mm/kyr.In contrast to the Mendeleev Ridge, the cores from the Lomonosov Ridge and the Podvodnikov Basin have shown a more complex paleomagnetic record with a relevant shift to negative inclinations significantly deeper downcore. This could signify a relevant difference in the sedimentation regimes between both ridges during the Quaternary.&#160; &#160;&#160;

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Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age

Nature Geoscience ◽

10.1038/s41561-021-00789-y ◽

2021 ◽

Author(s):

Jesse R. Farmer ◽

Daniel M. Sigman ◽

Julie Granger ◽

Ona M. Underwood ◽

François Fripiat ◽

...

Keyword(s):

Arctic Ocean ◽

Surface Waters ◽

Ice Age ◽

The Arctic ◽

Bering Strait ◽

Central Arctic Ocean ◽

Phytoplankton Productivity ◽

Nitrate Consumption ◽

Western Arctic ◽

Last Ice Age

AbstractSalinity-driven density stratification of the upper Arctic Ocean isolates sea-ice cover and cold, nutrient-poor surface waters from underlying warmer, nutrient-rich waters. Recently, stratification has strengthened in the western Arctic but has weakened in the eastern Arctic; it is unknown if these trends will continue. Here we present foraminifera-bound nitrogen isotopes from Arctic Ocean sediments since 35,000 years ago to reconstruct past changes in nutrient sources and the degree of nutrient consumption in surface waters, the latter reflecting stratification. During the last ice age and early deglaciation, the Arctic was dominated by Atlantic-sourced nitrate and incomplete nitrate consumption, indicating weaker stratification. Starting at 11,000 years ago in the western Arctic, there is a clear isotopic signal of Pacific-sourced nitrate and complete nitrate consumption associated with the flooding of the Bering Strait. These changes reveal that the strong stratification of the western Arctic relies on low-salinity inflow through the Bering Strait. In the central Arctic, nitrate consumption was complete during the early Holocene, then declined after 5,000 years ago as summer insolation decreased. This sequence suggests that precipitation and riverine freshwater fluxes control the stratification of the central Arctic Ocean. Based on these findings, ongoing warming will cause strong stratification to expand into the central Arctic, slowing the nutrient supply to surface waters and thus limiting future phytoplankton productivity.

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Arctic Ocean

Radiocarbon ◽

10.1017/s0033822200044301 ◽

1988 ◽

Vol 30 (3) ◽

pp. 277-277

Keyword(s):

Arctic Ocean ◽

Arctic Basin ◽

The Arctic ◽

Sedimentation Rates ◽

University Of Wisconsin ◽

The University

This study was undertaken in cooperation with David Clark of the University of Wisconsin in order to confirm the previous estimates of low sedimentation rates in the Arctic Basin (see Table 7).

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Arctic Ocean State-Changes: Self Interests and Common Interests

The Yearbook of Polar Law Online ◽

10.1163/22116427-91000026 ◽

2009 ◽

Vol 1 (1) ◽

pp. 511-525

Author(s):

Paul Arthur Berkman

Keyword(s):

Arctic Ocean ◽

The Arctic ◽

International Governance ◽

State Change ◽

Central Arctic Ocean ◽

Nation States ◽

Free Region ◽

The Arctic Ocean ◽

Challenges And Opportunities ◽

State Changes

Abstract Environmental and geopolitical state-changes are the underlying first principles of the diverse stakeholder positioning in the Arctic Ocean. The Arctic Ocean is changing from an ice-covered region to an ice-free region during the summer, which is an environmental state-change. As provided under the framework of the United Nations Convention on the Law of the Sea (UNCLOS), the central Arctic Ocean currently involves “High-Seas” (beyond the “Exclusive Economic Zones”) and the underlying “Area” of the deep-sea floor (beyond the “Continental Shelves”). Governance applications of this ‘donut’ demography – with international space surrounded by sovereign sectors – would be a geopolitical state-change in the Arctic Ocean. International governance strategies and applications for the central Arctic Ocean have far-reaching implications for the stewardship of other international spaces, which between Antarctica and the ocean beyond national jurisdictions account for nearly 75 percent of the Earth’s surface. In view of planetary-scale strategies for humankind, with frameworks such as climate, the Arctic Ocean underscores the challenges and opportunities to balance the governance of nation states and international spaces centuries into the future.

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Arktisk råds rolle i polarpolitikken

Nordlit ◽

10.7557/13.2314 ◽

2012 ◽

Vol 16 (1) ◽

pp. 205 ◽

Cited By ~ 1

Author(s):

Torbjørn Pedersen

Keyword(s):

United States ◽

Arctic Ocean ◽

The United States ◽

The Arctic ◽

Arctic Council ◽

The Third ◽

The Arctic Ocean ◽

Foreign Policies

This article discusses what role(s) member governments want the Arctic Council to have in Arctic affairs. It compares the foreign policies of the five littoral states of the Arctic Ocean: Canada, Denmark, Norway, Russia, and the United States. It identifies and examines three determining debates on a ministerial level over the Arctic Council and the issues it might address: The first debate preceded the Arctic Council's creation in 1996; the second thrived as the five Arctic littoral states convened in Ilulissat, Greenland in 2008; and the third followed a political shift inthe United States in 2009.

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Near-Inertial Mixing in the Central Arctic Ocean

Journal of Physical Oceanography ◽

10.1175/jpo-d-13-0133.1 ◽

2014 ◽

Vol 44 (8) ◽

pp. 2031-2049 ◽

Cited By ~ 23

Author(s):

Ilker Fer

Keyword(s):

Arctic Ocean ◽

Vertical Mixing ◽

The Arctic ◽

Storm Event ◽

Central Arctic Ocean ◽

Long Time ◽

Wave Induced ◽

The Waves ◽

Inertial Energy ◽

Made In

Abstract Observations were made in April 2007 of horizontal currents, hydrography, and shear microstructure in the upper 500 m from a drifting ice camp in the central Arctic Ocean. An approximately 4-day-long time series, collected about 10 days after a storm event, shows enhanced near-inertial oscillations in the first half of the measurement period with comparable upward- and downward-propagating energy. Rough estimates of wind work and near-inertial flux imply that the waves were likely generated by the previous storm. The near-inertial frequency band is associated with dominant clockwise rotation in time of the horizontal currents and enhanced dissipation rates of turbulent kinetic energy. The vertical profile of dissipation rate shows elevated values in the pycnocline between the relatively turbulent underice boundary layer and the deeper quiescent water column. Dissipation averaged in the pycnocline is near-inertially modulated, and its magnitude decays approximately at a rate implied by the reduction of energy over time. Observations suggest that near-inertial energy and internal wave–induced mixing play a significant role in vertical mixing in the Arctic Ocean.

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