The dissolved Beryllium isotope composition of the Arctic Ocean

Abstract. Arctic warming is projected to continue throughout the coming century. Yet, our currently limited understanding of the Arctic Ocean carbon cycle hinders our ability to predict how changing conditions will affect local Arctic ecosystems, regional carbon budgets, and global climate. We present here the first set of concurrent, full-depth, dual-isotope profiles for dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and suspended particulate organic carbon (POCsusp) at two sites in the Canada Basin of the Arctic Ocean. The carbon isotope composition of sinking and suspended POC in the Arctic contrasts strongly with open ocean Atlantic and Pacific sites, pointing to a combination of inputs to Arctic POCsusp at depth, including surface-derived organic carbon (OC), sorbed/advected OC, and OC derived from in situ DIC fixation. The latter process appears to be particularly important at intermediate depths, where mass balance calculations suggest that OC derived from in situ DIC fixation contributes up to 22% of POCsusp. As in other oceans, surface-derived OC is still a dominant source to Arctic POCsusp. Yet, we suggest that significantly smaller vertical POC fluxes in the Canada Basin make it possible to see evidence of DIC fixation in the POCsusp pool even at the bulk isotope level.

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Oxygen isotope composition of living Neogloboquadrina pachyderma (sin.) in the Arctic Ocean

Earth and Planetary Science Letters ◽

10.1016/s0012-821x(96)00211-7 ◽

1997 ◽

Vol 146 (1-2) ◽

pp. 47-58 ◽

Cited By ~ 104

Author(s):

D. Bauch ◽

J. Carstens ◽

G. Wefer

Keyword(s):

Arctic Ocean ◽

Oxygen Isotope ◽

Isotope Composition ◽

Oxygen Isotope Composition ◽

The Arctic ◽

Neogloboquadrina Pachyderma ◽

The Arctic Ocean

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Carbon dynamics in the western Arctic Ocean: insights from full-depth carbon isotope profiles of DIC, DOC, and POC

Biogeosciences Discussions ◽

10.5194/bgd-8-10677-2011 ◽

2011 ◽

Vol 8 (5) ◽

pp. 10677-10696

Author(s):

D. R. Griffith ◽

A. P. McNichol ◽

L. Xu ◽

F. A. McLaughlin ◽

R. W. Macdonald ◽

...

Keyword(s):

Organic Carbon ◽

Arctic Ocean ◽

Carbon Isotope ◽

Dissolved Inorganic Carbon ◽

Isotope Composition ◽

Canada Basin ◽

The Arctic ◽

Arctic Ecosystems ◽

The Arctic Ocean

Abstract. Arctic warming is projected to continue throughout the coming century. Yet, our currently limited understanding of the Arctic Ocean carbon cycle hinders our ability to predict how changing conditions will affect local Arctic ecosystems, regional carbon budgets, and global climate. We present here the first set of concurrent, full-depth, dual-isotope profiles for dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and suspended particulate organic carbon (POCsusp) at two sites in the Canada Basin of the Arctic Ocean. The carbon isotope composition of sinking and suspended POC in the Arctic contrasts strongly with open ocean Atlantic and Pacific sites, pointing to a combination of inputs to Arctic POCsusp at depth, including surface-derived organic carbon (OC), sorbed/advected OC, and OC derived from in situ DIC fixation. The latter process appears to be particularly important at intermediate depths, where mass balance results suggest that OC derived from in situ DIC fixation contributes up to 22% of POCsusp. As in other oceans, surface-derived OC is still a dominant source to Arctic POCsusp. Yet, we suggest that significantly smaller vertical POC fluxes in the Canada Basin make it possible to see evidence of DIC fixation in the POCsusp pool even at the bulk isotope level.

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Geochemical evidence of a floating Arctic ice sheet and underlying freshwater in the Arctic Mediterranean in glacial periods

10.5194/egusphere-egu21-12910 ◽

2021 ◽

Author(s):

Walter Geibert ◽

Jens Matthiessen ◽

Ingrid Stimac ◽

Jutta Wollenburg ◽

Ruediger Stein

Keyword(s):

Arctic Ocean ◽

Isotope Composition ◽

Ice Sheets ◽

The Arctic ◽

Theoretical Modelling ◽

Sea Level Changes ◽

Liquid Form ◽

Nordic Seas ◽

The Arctic Ocean ◽

Non Linear

Numerous studies have addressed the possible existence of large floating ice sheets in the glacial Arctic Ocean from theoretical, modelling, or seafloor morphology perspectives. Here, we add evidence from the sediment record that support the existence of such freshwater ice caps in certain intervals, and we discuss their implications for possible non-linear and rapid behaviour of such a system in the high latitudes.We present sedimentary activities of 230Th together with 234U/238U ratios, the concentrations of manganese, sulphur and calcium in the context of lithological information and records of microfossils and their isotope composition. New analyses (PS51/038, PS72/396) and a re-analysis of existing marine sediment records (PS1533, PS1235, PS2185, PS2200, amongst others) in view of the naturally occurring radionuclide 230Thex and, where available, 10Be from the Arctic Ocean and the Nordic Seas reveal the widespread occurrence of intervals with a specific geochemical signature. The pattern of these parameters in a pan-Arctic view can best be explained when assuming the repeated presence of freshwater in frozen and liquid form across large parts of the Arctic Ocean and the Nordic Seas.Based on the sedimentary evidence and known environmental constraints at the time, we develop a glacial scenario that explains how these ice sheets, together with eustatic sea-level changes, may have affected the past oceanography of the Arctic Ocean in a fundamental way that must have led to a drastic and non-linear response to external forcing.This concept offers a possibility to explain and to some extent reconcile contrasting age models for the Late Pleistocene in the Arctic Ocean. Our view, if adopted, offers a coherent dating approach across the Arctic Ocean and the Nordic Seas, linked to events outside the Arctic.

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