Network for Biological Invasions and Dispersal Research

MITACS Seminar at the University of New Brunswick, Fredericton

Tuesday, 12 October, 2010,

Meredith Greer

of Bates College, Maine

will speak

Toward understanding the role of Gloeotrichia echinulata in eutrophication of lakes: early modeling results

3:30 PM, Tilley 223, University of New Brunswick, Fredericton

Abstract: Gloeotrichia echinulata is a large nitrogen-fixing cyanobacterium that has been identified in several northern New England lakes.  We hypothesize that G. echinulata could accelerate eutrophication by contributing to increased quantities of nitrogen and phosphorus in the water column.  A G. echinulata research group has collected data at Lake Sunapee, New Hampshire, USA, for several years.  In the past year, mathematical modeling has begun.  Long-term, we hope to identify key environmental factors in G. echinulata population dynamics.  These will help us better understand the role of G. echinulata in moving phosphorus from the sediment, and nitrogen from the air, into the water column. To start the math modeling portion of this project, we constructed a framework for large-scale G. echinulata dynamics within a single year.  We then focused on the beginning of this framework, namely the germination of dormant akinetes of G. echinulata , the time spent post-germination in the sediment of the lake, and subsequent recruitment into the water column.  The literature suggests possible influences of light, temperature, and growing degree days on these early stages in the life cycle of G. echinulata.   In this talk, we present modeling approaches to testing these hypotheses, as well as results and possible interpretations.