Paleoclimatology

My PhD work investigated the variability of sea-surface temperature and salinity in the northern Gulf of Mexico over the last several thousand years. As a proxy for these variables, I used plankton shells found in sediment cores collected from the sea-floor: the deeper the shells are found in the cores, the further back in time they were deposited. Specifically, I measure stable isotope and trace metal ratios locked in the calcite shells of planktic foraminifera to glimpse into past sea-surface conditions.

I also sailed on IODP Expedition 353 and intend to work with sediments from the Bay of Bengal to investigate the variability of the Indian monsoon during the last Ice Age.

Sediment cores from the Bay of Bengal. This photo depicts an ash layer.

Sediment cores from the Bay of Bengal. This photo depicts an ash layer.

A schematic of a sediment trap.

A schematic of a sediment trap.

A multicore in the northern Gulf of Mexico

A multicore in the northern Gulf of Mexico

Foraminiferal Ecology

To understand the modern ecology of planktic foraminifera, in collaboration with with the USGS, I use a sediment trap in the Gulf of Mexico. This instrument collects plankton shells before they are deposited on the seafloor. Using these samples, we can calibrate the chemistry of the shells to temperature and salinity. Ultimately, the sediment trap provides better estimates for our downcore geochemical measurements. 


 

Proxy Uncertainty

I am interested in statistically quantifying  and modeling uncertainties in proxies. How can we best listen to what the proxies (foraminifera, corals etc.) are telling us? I am interested in forward modeling proxy data from the instrumental record and using the results as a metric to compare paleoclimate output from general circulation models used to simulate global climate. How important are these proxy uncertainties for model-data comparisons

Forward modeling results from INFAUNAL compared to data offset between two foraminiferal morphotypes.

Forward modeling results from INFAUNAL compared to data offset between two foraminiferal morphotypes.


Collecting corals on Ranongga, western Solomon Islands

Collecting corals on Ranongga, western Solomon Islands


Paleogeodesy

Another line of research I am involved with is coral paleogeodesy, in collaboration with Fred Taylor. At island arcs where two plates converge at a subduction zone, earthquakes are abundant and cause uplift and subsidence. Corals, which are extremely sensitive to sea-level can be killed due to abrupt uplift and become part of the island. We can use the elevations of precisely-dated fossil corals on islands to understand earthquake history. Currently I work on corals from the western Solomon Islands.