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20th century warming in the lower Florida Keys was dominated by increasing winter temperatures

February 23, 2024

Long-lived Atlantic coral species like Orbicella faveolata are important archives of oceanographic change in shallow, marine environments like the Florida Keys. Not only can coral-based records extend for multiple centuries beyond the limits of the instrumental record, but they can also provide a more accurate representation of in situ conditions than gridded interpolated sea-surface temperature (SST) products for nearshore reef environments. We use the coral Sr/Ca paleothermometer to produce a 150-year (1830–1980 C.E.) monthly SST reconstruction from an O. faveolata colony collected in the Marquesas Keys, FL, USA. An important feature of our record is a significant 20th-century warming trend in winter SSTs. We hypothesize that the winter warming trend was driven partially by a decrease in upwelling associated cyclonic eddies spinning off the Florida Current. A long-term weakening of winter Florida Current transport over the 20th century could be responsible for decreased cyclonic eddy formation in the Florida Straits. Another feature of the record is pronounced multidecadal fluctuations of mean annual warming and cooling in the record, which correspond to Atlantic Multidecadal Variability (AMV), with the AMV lagging behind western Florida Keys temperatures by 5–11 years. Strong coherence between coral-based SST reconstructions in the western Florida Keys with broader scale Atlantic oceanographic trends over the past century suggests a common driver of regional SST variability.

Publication Year 2024
Title 20th century warming in the lower Florida Keys was dominated by increasing winter temperatures
DOI 10.1029/2023PA004748
Authors Jennifer A. Flannery, Julie N. Richey, Lauren Toth, Madelyn Jean Mette
Publication Type Article
Publication Subtype Journal Article
Series Title Paleoceanography and Paleoclimatology
Index ID 70251783
Record Source USGS Publications Warehouse
USGS Organization St. Petersburg Coastal and Marine Science Center