6, 000‐Year Reconstruction of Modified Circumpolar Deep Water Intrusion and Its Effects on Sea Ice and Penguin in the Ross Sea. Issue 15 (2nd August 2021)

• Record Type: Journal Article
• Authors: Xu, Q. B.; Yang, L. J.; Gao, Y. S.; Sun, L. G.; Xie, Z. Q.
• Is Part Of: Geophysical research letters. Volume 48:Issue 15(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-02
• Subjects: Adélie penguin -- cadmium -- Holocene -- Modified Circumpolar Deep Water -- Ross Sea; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2021GL094545
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The Ross Sea has the world's largest marine protected area. Modified Circumpolar Deep Water (MCDW) has significant effects on physical and biological processes in the Ross Sea. Totally 13 penguin ornithogenic sediment profiles were collected from Inexpressible Island, Ross Sea, and the Cd/P ratios were used as a proxy of MCDW intrusion, enabling to reconstruct the variability of MCDW intrusion into the Ross Sea during the past 6, 000 years. During the intervals of ∼0.7–1.6 and ∼2.8–6.0 kyr BP, enhanced MCDW intrusion increased the heat supply which warmed the surface water and reduced the coastal sea ice concentration. By contrast, reduced MCDW intrusion during ∼1.6–2.8 kyr BP caused a decrease in the penguin population via restricting food supply and/or increasing sea ice concentration. Thus, changes in MCDW were responsible for driving millennial changes in sea ice and penguin population in the Ross Sea. Plain Language Summary: Modified Circumpolar Deep Water (MCDW) has important impacts on physical and biological processes in the Ross Sea. Although high‐resolution spatiotemporal records of MCDW intrusion into the modern Ross Sea have been obtained using various methods, the intrusion of this water mass into the Ross Sea during the Holocene has not previously been reconstructed. Here, we use measurements of the Cd/P ratio in ornithogenic sediments to reconstruct the variability of the intrusion of the MCDW into the Ross Sea during the past 6, 000 years. MCDW intrusion was enhanced during the intervals of ∼0.7–1.6 and ∼2.8–6.0 kyr BP, when the resulting increased heat supply warmed the surface water and reduced the concentration of coastal sea ice. By contrast, when MCDW intrusion was reduced during ∼1.6–2.8 kyr BP, the resulting restriction of the food supply and/or increased coastal sea ice concentration caused a decrease in the penguin population. Our results demonstrate that the Cd/P ratio can be used as a proxy of MCDW intrusion and that changes in the intrusion of the MCDW were responsible for driving millennial‐scale changes in sea ice and the penguin population in the Ross Sea. Key Points: Cd/P profiles from ornithogenic sediments can be used as a proxy of Modified Circumpolar Deep Water (MCDW) intrusion Reconstruction of MCDW intrusion in the Ross Sea during the past 6, 000 years MCDW intrusion drives millennial changes in sea ice concentration and penguin population in the Ross Sea