Pronounced centennial-scale Atlantic Ocean climate variability correlated with Western Hemisphere hydroclimate

Abstract

Surface-ocean circulation in the northern Atlantic Ocean influences Northern Hemisphere climate. Century-scale circulation variability in the Atlantic Ocean, however, is poorly constrained due to insufficiently-resolved paleoceanographic records. Here we present a replicated reconstruction of sea-surface temperature and salinity from a site sensitive to North Atlantic circulation in the Gulf of Mexico which reveals pronounced centennial-scale variability over the late Holocene. We find significant correlations on these timescales between salinity changes in the Atlantic, a diagnostic parameter of circulation, and widespread precipitation anomalies using three approaches: multiproxy synthesis, observational datasets, and a transient simulation. Our results demonstrate links between centennial changes in northern Atlantic surface-circulation and hydroclimate changes in the adjacent continents over the late Holocene. Notably, our findings reveal that weakened surface-circulation in the Atlantic Ocean was concomitant with well-documented rainfall anomalies in the Western Hemisphere during the Little Ice Age.

Quantifying Uncertainty in Sr/Ca‐Based Estimates of SST From the Coral Orbicella faveolata

“…This suggests that given a long enough time series, researchers could statistically discern decadal‐scale mean shifts in annual or seasonal temperature of 2 °C, and multidecadal shifts in temperature (30+ years) of less than 1 °C using Sr/Ca in O. faveolata . It would be possible, for example, to detect the approximately 1 °C cooling that occurred in the Gulf of Mexico during the Little Ice Age (1450–1850; Richey et al, ; Thirumalai et al, ) by comparing 30‐year Sr/Ca‐SST time series from a modern coral to one that grew during the Little Ice Age. Similarly, our results suggest that by applying running means though coral‐based Sr/Ca records, multidecadal modes of variability such as the Atlantic Multidecadal Oscillation could be resolved (Flannery et al, ).…”

Deciphering the Variability in Mg/Ca and Stable Oxygen Isotopes of Individual Foraminifera

“…Core top GeoB 17426‐2 has a calibrated AMS‐ 14 C age of 309 year BP (Table ). Core top 2010‐GB2‐MC from the GoM was collected in Summer 2010 on the R/V Cape Hatteras and was AMS‐ 14 C dated as modern (>1950 CE; Thirumalai et al, ).…”

Considerations for Globigerinoides ruber (White and Pink) Paleoceanography: Comprehensive Insights From a Long‐Running Sediment Trap

“…The continental slope of the nGoM is punctuated with deep basins (>1,000 m) that have rapid sediment accumulation rates due to the large influx of terrigenous material delivered via the Mississippi River. The combination of high sedimentation rates, concurrent deposition of both marine and terrestrial material, and proximity to Mississippi River discharge makes the nGoM an ideal location for assessing linkages between continental and marine climate change (Hill et al, ; Meckler et al, ; Richey et al, ; Thirumalai et al, )…”

“…The continental slope of the nGoM is punctuated with deep basins (>1,000 m) that have rapid sediment accumulation rates due to the large influx of terrigenous material delivered via the Mississippi River. The combination of high sedimentation rates, concurrent deposition of both marine and terrestrial material, and proximity to Mississippi River discharge makes the nGoM an ideal location for assessing linkages between continental and marine climate change (Hill et al, 2006;Meckler et al, 2008;Richey et al, 2011;Thirumalai et al, 2018) The planktic foraminifer, G. ruber, has a cosmopolitan distribution in the tropical to midlatitude oceans, and its geochemistry is widely used as a proxy recorder of changes in mean annual SST and SSS. It is well suited for paleoceanographic reconstruction of surface hydrographic conditions because both its oxygen isotopic composition (Anand et al, 2003;Venancio et al, 2017) and its distribution in depth-stratified plankton tows (e.g., Jentzen et al, 2018;Schmuker & Schiebel, 2002) indicate that it completes its life cycle within the nearsurface part of the water column (0-50 m).…”