Scanning electron microscope pictures of the planktonic foraminifer Turborotalita quinqueloba. Scale bars = 100 micron. Credit: Flor Vermassen
However, the level of sea ice throughout this duration has actually been intensely disputed and there is no agreement, limiting understanding of this period and the ability of researchers to simulate it in climate models.
To address this, a team of marine geology scientists from the Department of Marine Geological Sciences at Stockholm University analyzed the microfossil material of an array of sediment cores from websites that today lie straight underneath the thickest parts of the modern Arctic ice bag. In these cores, they examined the variability in the occurrence and composition of planktonic foraminifera, a kind of free-floating, shell-building unicellular zooplankton that is sensitive to changes in oceanographic and environmental conditions.
The scientists discovered high abundances of the typically subpolar, Atlantic-water types Turborotalita quinqueloba, recording a massive expansion of the species far into the central Arctic Ocean. The eco-friendly choice of T. quinqueloba for mainly ice-free, seasonally productive waters usually provide in the Atlantic Ocean recommends that it was following similar conditions that had actually spread out to the central Arctic Ocean. The absence of summertime sea ice and the increased impact of Atlantic currents in the Arctic domain during the Last Interglacial are comparable to ocean transformations being observed today in parts of the Arctic, and jointly described as Atlantification of the Arctic Ocean.
” The finding that the Arctic Ocean was seasonally ice-free during the Last Interglacial is fretting due to the fact that this duration would have been just around 1.5 ° C above pre-industrial levels, equivalent to the targets of the Paris Agreement. The worldwide sea level is estimated to have been numerous meters greater than at present,” said Flor Vermassen.
The scientists propose the Last Interglacial as the most recent and potentially most appropriate geological date for investigating a seasonally ice-free Arctic Ocean, especially if the goals of the Paris Agreement are not gone beyond.
” To totally understand the physical conditions and environment of this unfamiliar Arctic throughout the Last Interglacial, extra quantitative proxy restorations of sea-surface temperature and other water mass specifications are required, along with targeted climate and oceanographic model studies of the very same duration,” stated Flor Vermassen.
Reference: “A seasonally ice-free Arctic Ocean throughout the Last Interglacial” by Flor Vermassen, Matt ORegan, Agatha de Boer, Frederik Schenk, Mohammad Razmjooei, Gabriel West, Thomas M. Cronin, Martin Jakobsson and Helen K. Coxall, 3 August 2023, Nature Geoscience.DOI: 10.1038/ s41561-023-01227-x.
The research study was moneyed by the Swedish Research Council.
Picture taken in the limited ice zone of the Arctic Ocean from the Swedish icebreaker Oden, summer season of 2021. Credit: Flor Vermassen
Analysis of microfossil material in sediment cores reveals that throughout the Last Interglacial, a species usually found in subpolar areas associated with Atlantic water expanded significantly into the Arctic Ocean. This indicates that the Arctic experienced ice-free summers during this time. The findings are released in Nature Geoscience.
Arctic sea ice, an essential part of the Earth system, is disappearing quick under environment warming. Summertime sea ice is anticipated to disappear entirely within this century. To get a deeper understanding of the climate dynamics in a world without Arctic sea ice, scientists have actually turned to analogs from the geological past.
” The Last Interglacial, in between 129,000 and 115,000 years BP, is a fascinating period to study since it is the last time in Earths history when global average temperatures were comparable or possibly greater than presently and sea levels were substantially greater, up to +6 to +9 m,” said Flor Vermassen, a postdoctoral scientist at Stockholm University.
Analysis of microfossil material in sediment cores reveals that during the Last Interglacial, a types normally discovered in subpolar regions associated with Atlantic water broadened significantly into the Arctic Ocean. The scientists found high abundances of the typically subpolar, Atlantic-water species Turborotalita quinqueloba, documenting a massive expansion of the types far into the main Arctic Ocean. The eco-friendly preference of T. quinqueloba for primarily ice-free, seasonally productive waters typically provide in the Atlantic Ocean suggests that it was following comparable conditions that had actually spread out to the main Arctic Ocean. The lack of summertime sea ice and the increased influence of Atlantic currents in the Arctic domain during the Last Interglacial are comparable to ocean transformations being observed today in parts of the Arctic, and jointly referred to as Atlantification of the Arctic Ocean.