Research: Detailed Climate History Time Series

Sea-surface temperature in the Gulf of Mexico (GOM) is an important factor in regional and global climate. Along with the Caribbean Sea, and western tropical North Atlantic, the Gulf of Mexico is part of the Atlantic Warm Pool, the Atlantic portion of the Western Hemisphere Warm Pool (Fig. 1). The Atlantic Warm Pool is defined by the region covered by water warmer than 28.5ºC and constitutes a large part of the tropical heat engine, supplying moisture to the atmosphere and latent heat to North America as it evolves from early spring to early fall. Climate records from the northern GOM provide information on the magnitude and rate of natural climate variability within the Atlantic Warm Pool, which are critical to understanding natural climate-forcing mechanisms and feedbacks.

Deep-sea sediments of the northern Gulf of Mexico provide an archive of climate history with high sedimentation rates that allow for decadalscale resolution. Within the sediments are calcareous microfossils, specifically planktic foraminifers (Fig. 2), that provide a record of ocean conditions, such as temperature and salinity.

We are currently working on a suite of gravity and box cores (Fig. 3) from the northern Gulf of Mexico to reconstruct past natural climate variability over the late Holocene. Analyses include faunal assemblage and elemental and stable isotope measurement of specific species of planktic foraminifers.

Figure 1. Cartoon of the Western Hemisphere Warm Pool during September. Stars represent the core locations under study.

Figure 2. Scanning electron microsope image of the planktic foraminifer Globigerinoides ruber. Photo credit: Julie Richey.

Figure 3. 6" and 4" subcores sampled from a giant box core. Photo credit: Lisa Osterman.