New paper finds SW Pacific Ocean surface temperatures were about the same as today, ~200,000 years ago
A new paper published in Quaternary Research finds sea surface temperatures in the SW Pacific Ocean were about the same as the present 200,000 years ago. According to the authors, “Statistical results suggest that annual averages of sea-surface temperature (SST) and salinity (SSS) at ~ 197,000 [years ago] were not significantly different from and ~ 1.2 higher than at present, respectively.”The authors also find sea levels in the SW Pacific were up to ~10 meters [~32 feet] higher than the present during the last interglacial ~120,000 years ago.
Horizontal axis is thousands of years before the present
MIS 7 interglacial sea-surface temperature and salinity reconstructions from a southwestern subtropical Pacific coral
Ryuji Asamia, b, , ,
Yasufumi Iryuc, d,
a Trans-disciplinary Research Organization for Subtropical Island Studies (TRO-SIS), University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan
b Faculty of Science, Department of Physics and Earth Sciences, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan
c Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601, Japan
d Institute of Geology and Paleontology, Graduate School of Science, Tohoku University, 6-3 Aramaki-aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
e Physical Oceanography Laboratory, Department of Geophysics, Graduate School of Science, Tohoku University, 6-3 Aramaki-aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
f Research School of Earth Sciences, The Australian National University, Bldg 61, Mills Road, Acton, ACT 0200, Australia
g Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA
We generated a 5.5-yr snapshot of biweekly-to-monthly resolved time series of carbon and oxygen isotope composition (δ13C and δ18O) and Sr/Ca and Mg/Ca from annually banded aragonite skeleton of a ~ 197 ka pristine Porites coral collected at Niue Island (19°00′S, 169°50′W) in the southwestern subtropical Pacific Ocean. This report is the first of a high-resolution coral-based paleoclimate archive during the Marine Isotope Stage (MIS) 7 interglacial. Statistical results suggest that annual averages of sea-surface temperature (SST) and salinity (SSS) at ~ 197 ka were not significantly different from and ~ 1.2 higher than at present, respectively. Monthly mean variations showed increased SSS at ~ 197 ka that was higher (1.4–1.9 relative to today) in the austral summer than in the austral winter. Monthly SST and SSS anomalies at ~ 197 ka indicated smaller amplitudes by ~ 0.3°C (11%) and ~ 0.3 (24%) relative to the present, possibly suggesting less influence of interannual climate variability around Niue. Our results, taken together with other climate proxy records, imply seasonal and interannual modulation of thermal and hydrological conditions, different from today, in the southwestern subtropical Pacific Ocean associated with the Western Pacific Warm Pool and the South Pacific Convergence Zone variability during the MIS 7 interglacial.
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