Research: Graduate Student Profile

 

Snapshots...

Louisa Bradtmiller
Geochemistry, LDEO

B.A. Geology, Smith College, 2002.

"I think the relaxed atmosphere at Lamont is what actually makes it a very engaging and productive place to be a student - some of the most interesting conversations I’ve had about my courses or research have happened at coffee hour, over lunch, or after a soccer game."

Ocean Nutrients and Their Influence on Paleoclimate.

Ice core records show that atmospheric pCO₂ levels have fluctuated throughout the past 700,000 years in approximately 100,000-year cycles. These cycles also correspond to glacial-interglacial cycles, but the mechanism linking lower pCO₂ and glaciations (and vice verse) is unclear. I’m interested in how changes in the ocean's nutrient cycles over time have possibly contributed to these changes. My research tests a hypothesis proposed by Princeton researchers in 2001, which suggests that if silica (a nutrient important to small organisms called diatoms) escaped from the Southern Ocean during glacial periods, it would have been used by diatoms in equatorial regions of the ocean instead. This has the potential to draw CO₂ out of the atmosphere and into the ocean.

I'm testing this hypothesis using deep-sea cores to reconstruct opal (silica) fluxes through time in equatorial and Southern Ocean sites across the globe. I also use trace element and Uranium-series chemistry to help unravel the different factors in play. This research is particularly important in light of current increases in greenhouse gas emissions- until we understand the drivers of natural CO₂ fluctuations, the scientific community will have a hard time predicting the possible consequences of increased atmospheric CO₂ in the future.

Please visit my website for more information.

Advisors: Robert Anderson (primary advisor), Doug Martinson, Lloyd Burckle.