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Karen Filbee-Dexter

Trophic coupling between kelp beds and adjacent deep-water communities

Karen Filbee-Dexter
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Originally from St. Margarets Bay, Nova Scotia I completed my BSc in Biology at Dalhousie University where I developed my interest in benthic ecology and coastal ecosystem dynamics.

Robert Scheibling

Biology, Dalhousie University

05/2010 - present

Ecosystem Function, EF-11: Ecosystem phase shifts

This project examines deep-living populations of green sea urchins along the Atlantic coast of Nova Scotia and their connectivity to shallow kelp bed ecosystems. I am particularly interested in the importance of drift kelp export from shallow kelp beds to adjacent  food-limited areas and the impact of this subsidy on the reproductive condition of deep-living sea urchins.  


The specific project/thesis aims are:

1. Measure the loss of attached kelp in the shallows and the export of detached kelp to depositional areas following strong storm events.

2. Document the duration of drift subsidy and the response of deep-living sea urchins to pulses of drift kelp.

3. Measure the reproductive condition of deep-living sea urchins receiving drift kelp subsidy and compare it to shallow populations within kelp beds.

This project has shown for the first time that substantial drift kelp deposition occurs off the coast of Nova Scotia and that sea urchins in deep depositional areas can be highly reproductive. These deep populations exist in a thermal refuge from a disease that decimates warmer shallow populations and may play an important ecological role in restoring shallow populations after mass mortality. Deep sea urchin populations may also play a key role in destructive grazing events in which sea urchins emerge from deep regions and graze kelp beds to unproductive sea urchin barrens.


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