TY - JOUR
T1 - Variations in deep-sea methane seepage linked to millennial-scale changes in bottom water temperatures ~ 50-6 ka, NW Svalbard margin
AU - Rasmussen, Tine L.
AU - El Bani Altuna, Naima
AU - Thomsen, Erik
N1 - Publisher Copyright:
© 2024. The Author(s).
PY - 2024/9/27
Y1 - 2024/9/27
N2 - During the last glaciation, the northern hemisphere experienced profound millennial-scale changes (termed Dansgaard-Oeschger (DO) events) in atmospheric and oceanic temperatures. In the North Atlantic, the fluctuations resulted in extremely unstable bottom water conditions with bottom water temperatures (BWT) varying up to > 5 °C. We have studied these changes in a core from 1,300 m water depth at Vestnesa Ridge, northwestern Svalbard margin to investigate a possible connection between BWT and seepage of methane from the seafloor covering the period ~ 50-6 ka. Beneath Vestnesa Ridge, gas hydrates containing vast amounts of methane are kept stable due to the high pressure and low temperatures. Release of gas is shown by numerous pockmarks on the seafloor. The pockmarks at 1,300 m water depth are presently inactive, but they bear witness of earlier activity. Our study shows that from ~ 50-6 ka, the core site experienced repeated increases in BWT and in the emissions of gas, both following the pattern of the DO events. This correspondence in time scale indicates that BWT was the primary forcing factor for the variability in methane release. However, the releases were delayed by up to > 1,000 years compared to the initial increase in BWT.
AB - During the last glaciation, the northern hemisphere experienced profound millennial-scale changes (termed Dansgaard-Oeschger (DO) events) in atmospheric and oceanic temperatures. In the North Atlantic, the fluctuations resulted in extremely unstable bottom water conditions with bottom water temperatures (BWT) varying up to > 5 °C. We have studied these changes in a core from 1,300 m water depth at Vestnesa Ridge, northwestern Svalbard margin to investigate a possible connection between BWT and seepage of methane from the seafloor covering the period ~ 50-6 ka. Beneath Vestnesa Ridge, gas hydrates containing vast amounts of methane are kept stable due to the high pressure and low temperatures. Release of gas is shown by numerous pockmarks on the seafloor. The pockmarks at 1,300 m water depth are presently inactive, but they bear witness of earlier activity. Our study shows that from ~ 50-6 ka, the core site experienced repeated increases in BWT and in the emissions of gas, both following the pattern of the DO events. This correspondence in time scale indicates that BWT was the primary forcing factor for the variability in methane release. However, the releases were delayed by up to > 1,000 years compared to the initial increase in BWT.
UR - http://www.scopus.com/inward/record.url?scp=85205275403&partnerID=8YFLogxK
U2 - 10.1038/s41598-024-72865-3
DO - 10.1038/s41598-024-72865-3
M3 - Journal article
C2 - 39333168
AN - SCOPUS:85205275403
SN - 2045-2322
VL - 14
SP - 22184
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 22184
ER -