Our research focuses on the chemical transformations and physical fluxes of naturally-occurring particles in the ocean, with an emphasis on rapid processes that alter these particles as they cross major earth system boundaries—e.g., into the ocean across coastlines, downward from the sunlit surface ocean through the “twilight zone”, and upward from the bottom through sediment resuspension, or through hydrothermal vents into cold, deep waters.

Cloudy sky at sea

Prospective students

My lab is currently recruiting graduate students interested in cross-disciplinary ocean carbon cycle research, and I am always interested in hearing from well-qualified University of Maine undergraduates who would like to gain experience with data analysis techniques.

Current projects (below) focus mainly on the ocean’s biological carbon pump which transfers organic carbon from the sunlit surface ocean into the interior.  Other current interests include modeling photochemical losses of heterogeneous organic matter from dynamic environments, development of new methods for autonomous, in situ measurements of organic carbon pools, and understanding the controls on particle sinking speed in the ocean.

Read more about graduate and undergraduate programs at the University of Maine’s School of Marine Sciences here.

Recovery of a profiling float in a small boat

Lab members

Spring Bloom and Carbon Export in the North Atlantic

With collaborators at MBARI and WHOI and support from NSF, we are using profiling floats equipped with biogeochemical sensors to investigate the timing, magnitude, and associated carbon export from the spring bloom in the North Atlantic Ocean.

EXPORTS sediment trap project

Neutrally buoyant sediment trapWe are characterizing the strength and variability in the ocean’s “biological carbon pump” across contrasting sites in the ocean. The observations will support development of better models to predict changes in the ocean’s biological carbon uptake. The EXPORTS program is a large, interdisciplinary and multi-institutional effort supported by the NASA Ocean Biology and Biogeochemistry program. The sediment trap team (led by Estapa at the University of Maine) is collecting and characterizing sinking particles using a flotilla of sediment traps, cameras, and innovative sampling techniques.