Semester of Graduation

Spring 2024

Degree

Master of Science (MS)

Department

Geography and Anthropology

Document Type

Thesis

Abstract

Caribbean sea surface temperatures (SST) have increased posing detrimental impacts to marine ecosystems (e.g., coral bleaching) and coastal regions (e.g., prolonged droughts). However, there is a lack of long-term instrumental records for this region that hinders our ability to understand past climate variability from the end of the Little Ice Age (1300–1850) to the current global warming trend. Caribbean SST’s have increased since 1982 at a mean rate of 0.3 ˚C per decade, but trends before 1982 are not well-known. Oceanic and atmospheric phenomena such as the Atlantic Multidecadal Oscillation, variations between warmer and colder SST anomalies every 20–30 years, and the Atlantic Warm Pool (AWP), a seasonal warm pool characterized by SST greater than 28.5 ºC, affect precipitation and hurricanes in this region. Understanding the spatial extents of the AWP, small versus large warm pools, since the Little Ice Age are unknown. One way to fill this knowledge gap is coral-based paleoclimate reconstructions. Several Haitian Siderastrea siderea coral microatolls from the Gulf of Gonâve are analyzed for monthly-resolved coral Sr/Ca and Ba/Ca to investigate variability of (1) SST, (2) the AWP and (3) river runoff from 1880–2009. A large AWP is characterized by extending past Guadalupe Island (60 ºW) in the eastern Caribbean whereas a small AWP extends to Haiti (72 ºW). The coral Sr/Ca-SST reconstruction reveals a mean annual warming trend of 2.8 ˚C to 2009 with winter minima increasing by 4.7 ˚C resulting in a decreased seasonal SST range of 3.5 ˚C. The winter trend in coral Sr/Ca may result from the rotated coral corallites from 1880–1929, but no such trend is present in coral Mg/Ca or Ba/Ca. Excluding this section yields a 1.13 ºC warming trend in winter SST from 1930–2009. Coral Ba/Ca anomalies coincide with precipitation events and satellite chlorophyll concentrations with a four-to-six months lag signifying that coral Ba/Ca anomalies track large river discharge as result of extreme precipitation events. Examination of mean annual summer SST in coral reconstructions across the Caribbean (e.g., Dry Tortugas, Little Cayman, Guadeloupe) reveals large AWPs occur with greater frequency towards the 21st century.

Date

4-17-2024

Committee Chair

DeLong, Kristine L.

Download

Available for download on Sunday, April 04, 2027

Share

COinS