The past always repeats itself, and global climate change is no exception. In fact, we might even say that the past prefers to repeat itself! Over the past 600,000 years, the climate has loyally trudged through one ice after another, six times in a row. How are these ice ages similar, and why? How are they different, and why? What drives their clockwork? These are just some of the questions driving my current research into the mechanisms and conditions of glacial-interglacial climate change in the Late Pleistocene. I am currently working primarily with sediment cores from our largest marine archive, the Pacific Ocean.
Extending about 11,000 miles, the Equatorial Pacific amounts to the greatest expanse of tropical ocean on Earth. Today, upwelling along the equator and the eastern boundary of South America brings more nutrients to the surface than the phytoplankton community can consume. How has the productivity of this massive region responded to changing climate conditions in the past? I focus on reconstructing productivity, dust flux, and nutrient utilization over the last 30kyr to identify the major drivers of the biological pump in this region.
Bathed in the oldest, most corrosive deep waters, the Northeast Pacific is not the easiest place for paleoceanography. As the high corrosivity dissolves the carbonaceous foraminifera, so to dissolves the possibility of constructing age models. The Northeast Pacific has been stuck in a dead zone, but in 2014, new cores were collected from the Juan de Fuca Ridge, bathymetrically high enough to escape complete carbonate dissolution. These foram-rich cores provide the opportunity to investigate a host of classic paleoceanographic questions in this region over the past 500,000yrs, including mass fluxes, surface productivity, and ocean circulation. Click on "Learn More" to take a look at some of my current projects.