UMaine Researchers Receive $500,000 Grant to Study Ocean Sediments
Contact: Pete Jumars, (207) 581-4381; Sara Lindsay, (207) 581-2739; Aimee Dolloff, (207) 581-3777
ORONO, Maine — Two University of Maine researchers have received a nearly $500,000 grant to combine and broaden their studies of the seafloor by looking at the ecological and biological processes of the creatures that live there.
The National Science Foundation awarded professors Pete Jumars and Sara Lindsay of UMaine’s School of Marine Sciences a three-year grant that will allow them to study animals that feed on sediment in the seabed and how those animals mix the sediment.
The seafloor animals – primarily worms, crustaceans and clams – play a critical role in the mixing and burial of organic material that arrives on the seabed and is either remineralized into carbon dioxide, ammonia, nitrate or phosphate and returned to the water column or is buried.
This burial is a critical process to an understanding of global warming because it’s the only major natural sink that takes both natural and anthropogenic carbon out of contact with the biosphere.
Many animals involved in this process have become locally extinct due to pollution and trawling by those in the fishing industry even before their functions are understood and despite the fact that marine muds cover the majority of the solid earth surface.
Separately, Jumars and Lindsay have studied different aspects of this process for several years, but are excited to combine their work.
With former UMaine doctoral candidate Kelly Dorgan, Jumars developed methods to visualize the burrowing of animals on the seafloor by making transparent polymer gels that mimic the mechanical properties of muds.
A major discovery of their work, aided by collaboration with UMaine engineering professor Eric Landis who is an expert on mechanical damage to concrete and wood composites, is that most animals burrow in muds by cracking them in a process analogous to splitting wood. In this next phase of work, Jumars and Lindsay will continue to use transparent analogs to identify the links between structure and function in subsurface burrowers.
They also will measure the consequences for sediment mixing and extend Lindsay’s prior research on chemosensory biology to test how chemosensory capabilities are involved in determining the way that animals steer cracks.
Chemosensory biology is the study of how the chemical senses of smell and taste interact with the environment, behavior, and success of organisms. For example, crabs find clams by the smell of their exhaled breath. Crabs are most successful when they hunt for the smell by moving across stream and then move upstream in the smell plume. Success is greatest at intermediate flow speeds; without flow the signal does not carry far, and in very turbulent flow the signal follows unpredictable paths and is dissipated quickly.
Humans on the other hand simply can use their sight to go after a piece of fruit in Jell-O with a fork or a spoon. Jumars and Lindsay expect to uncover how animals use smell and taste to locate rich patches of food in mud and sand and to understand the mechanics of how they free these materials from the surrounding medium and ingest them.
The timing of their award coincides with the 200th anniversary of Darwin’s birth and the 150th anniversary of his most famous book. Darwin’s last book, “The Formation of Vegetable Mould Through the Action of Worms,” concerned the mixing of soils by earthworms on land.
Dorgan and Jumars’ earlier work stirred some controversy by discrediting Darwin’s idea that worms are able to move through sediments by eating holes in the soil in front of them.
Jumars and Lindsay’s new work promises to reveal the details of eating and mixing in the vast submarine biome of marine sediments that cover the majority of Earth.