Holocene evolution of sea-surface temperature and salinity in the Gulf of Mexico

Paleoceanography and Paleoclimatology
By: , and 



Flows into and out of the Gulf of Mexico (GoM) are integral to North Atlantic ocean circulation, and help facilitate poleward heat transport in the Western Hemisphere. The GoM also serves as a key source of moisture for much of North America. Modern patterns of sea-surface temperature (SST) and salinity in the GoM are influenced by the Loop Current, its eddy-shedding dynamics, and the ensuing interplay with coastal processes. Here we present sub-centennial-scale records of SST and stable oxygen isotope composition of seawater (urn:x-wiley:25724517:media:palo21077:palo21077-math-000118Osw; a proxy for salinity) over the past 11,700 years using planktic foraminiferal geochemistry in sediments from the Garrison Basin, northwestern GoM. We measured urn:x-wiley:25724517:media:palo21077:palo21077-math-0002O and magnesium-to-calcium ratios in tests of Globigerinoides ruber (white) to generate quantitative estimates of past sea-surface conditions. Our results replicate and extend late Holocene reconstructions from the Garrison Basin, using which we then create composites of SST and urn:x-wiley:25724517:media:palo21077:palo21077-math-000318Osw. We find considerable centennial and millennial-scale variability in both SST and urn:x-wiley:25724517:media:palo21077:palo21077-math-000418Osw, although their evolution over the Holocene is distinct. Whereas mean-annual SSTs display pronounced millennial-scale variability, urn:x-wiley:25724517:media:palo21077:palo21077-math-000518Osw exhibits a secular trend spanning multiple millennia and points to increasing northwestern GoM surface salinity since the early Holocene. We then synthesize available Holocene records from across the GoM, and alongside the Garrison Basin composite, uncover substantial, yet regionally consistent, spatiotemporal variability. Finally, we discuss the role of the Loop Current and coastal influx of freshwater in imposing these heterogeneities. We conclude that dynamic surface-ocean changes occurred across the GoM over the Holocene.

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Publication type Article
Publication Subtype Journal Article
Title Holocene evolution of sea-surface temperature and salinity in the Gulf of Mexico
Series title Paleoceanography and Paleoclimatology
DOI 10.1029/2021PA004221
Volume 36
Issue 8
Year Published 2021
Language English
Publisher American Geophysical Union
Contributing office(s) St. Petersburg Coastal and Marine Science Center
Description e2021PA004221, 16 p.
Other Geospatial Gulf of Mexico
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