Research

A teaspoon of deep sea sediment can contain many millions of fossils. With so many fossils there is the opportunity to finely quantify ecological and evolutionary dynamics. We are developing a suite of approaches to do just this through rapid community shape analysis. We use an automated light microscope to image microscopic foraminifera (reflected light) and nannofossils (transmitted cross-polarized light). See updates to our shape software under AutoMorph. Current group members working on related projects include Leanne Elder, Allison Hsiang, Connie Plagge, Megan Mikenas, and Sara Kahanamoku-Snelling.

Biotic sensitivity is used to described the amount of biotic change expected in response to a given amount of environmental change. Although much effort has gone in to quantifying the closely related ‘climate sensitivity’ (i.e., the amount of temperature change in response to a given amount of CO₂ change), to date very few studies have examined biotic sensitivity on the long-time scales relevant to current global change. Current research efforts in my group on this topic are being led by Simon D’haenens and Chris Bowman.

 

Past mass extinctions provide a means to directly observe how species and communities respond to profound change. Extinction research in the Hull lab focuses on understanding the dynamics of Cretaceous-Paleogene mass extinction, the most recent of the Big Five mass extinctions. Michael Henehan leads our K-Pg related research efforts, with Megan Mikenas and Volkan Özen. Check out our recent work with the El Kef Coring Program!

We live, and have evolved, in an unusually cold climate state (i.e., a icehouse state) characterized by large continental ice sheets on the North and South Poles. Most of earth’s history was significantly warmer (i.e., a greenhouse state). The Eocene, from 55-35 million years ago, is the warmest interval of the Cenozoic and it gives us the chance to understand oceanographic and biotic dynamics in a warm, high CO₂ world like that we are rapidly creating. Celli sailed on Integrated Ocean Drilling Program Expedition 342 to drill sediments from the North Atlantic containing exceptional records of this important time interval.  She is currently leading the Eocene Stable Isotope consortium, a group of 10-labs on four continents, to finely detail the paleoceanographic evolution of the North Atlantic through the Eocene and to help generate a refined geological time scale (i.e., a cyclostratigraphic age model). The American based work in this collaboration is funded through a collaborative NSF grant (OCE-1335261) to Celli Hull, Richard Norris, and Jim Zachos, with post-doc Sandy Kirtland Turner and doctoral student Don Penman. At Yale, most Hull Undergraduate Research Assistants work, or have worked, on this project. The broader Eocene Stable Isotope Consortium also includes Phil Sexton, Paul Wilson, Paul Bown, Helen Coxall, Oli Friedrich, Wendy Kordesch, Diederik Liebrand, Kazu Moriya, Brad Opdyke, and Heiko Pälike.

As foraminifera are one of the key groups we use to understand ocean ecosystems through time, we have multiple research projects focused on better understanding their biology and ecology today. Multiple group members (Leanne Elder, Michael Henehan, and Maddie Shankle) and outside collaborators (Tom Ezard and Kirsty Edgar) work on related projects.