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Deep Ocean Storage of Heat and CO 2 in the Fram Strait, Arctic Ocean During the Last Glacial Period
Author(s) -
Ezat Mohamed M.,
Rasmussen Tine L.,
Hain Mathis P.,
Greaves Mervyn,
Rae James W. B.,
Zamelczyk Katarzyna,
Marchitto Thomas M.,
Szidat Sönke,
Skinner Luke C.
Publication year - 2021
Publication title -
paleoceanography and paleoclimatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.927
H-Index - 127
eISSN - 2572-4525
pISSN - 2572-4517
DOI - 10.1029/2021pa004216
Subject(s) - glacial period , oceanography , north atlantic deep water , thermohaline circulation , carbon cycle , geology , deep sea , benthic zone , arctic , climatology , paleontology , ecosystem , ecology , biology
The Fram Strait is the only deep gateway between the Arctic Ocean and the Nordic Seas and thus is a key area to study past changes in ocean circulation and the marine carbon cycle. Here, we study deep ocean temperature, δ 18 O, carbonate chemistry (i.e., carbonate ion concentration [CO 3 2− ]), and nutrient content in the Fram Strait during the late glacial (35,000–19,000 years BP) and the Holocene based on benthic foraminiferal geochemistry and carbon cycle modeling. Our results indicate a thickening of Atlantic water penetrating into the northern Nordic Seas, forming a subsurface Atlantic intermediate water layer reaching to at least ∼2,600 m water depth during most of the late glacial period. The recirculating Atlantic layer was characterized by relatively high [CO 3 2− ] and low δ 13 C during the late glacial, and provides evidence for a Nordic Seas source to the glacial North Atlantic intermediate water flowing at 2,000–3,000 m water depth, most likely via the Denmark Strait. In addition, we discuss evidence for enhanced terrestrial carbon input to the Nordic Seas at ∼23.5 ka. Comparing our δ 13 C and qualitative [CO 3 2− ] records with results of carbon cycle box modeling suggests that the total terrestrial CO 2 release during this carbon input event was low, slow, or directly to the atmosphere.