The Effects of Seagrass Restoration on Nitrogen Processing in Shallow Coastal Lagoons

Poster Number: 
250
Presenter/Primary Author: 
Luke Cole
Co-Authors: 
Karen J. McGlathery
Co-Authors: 
Robert J. Orth

Seagrass meadows are declining worldwide as a result of nutrient over-enrichment, warming water temperatures, and anthropogenic disturbances. In many areas, restoration projects are attempting to the reverse the trend with varying success. In the Virginia coastal lagoons, seagrasses (Zostera marina) were lost in the 1930’s due to a large hurricane impacting meadows already weakened by the wasting disease. A large-scale restoration effort has been underway since the early 2000’s and has resulted in >1000 acres of seagrass coverage. The restoration provides a chronosequence with seagrass meadows ranging from 2 to >10 years of age. We are evaluating the changes in nitrogen processing as the system undergoes a state change from a benthic algal state to a seagrass-vegetated state. We report our results on the effects of this state change with rates of nitrogen fixation. Trends for both sediment N-fix and leaf epiphyte N-fix increased with increasing bed age. Rates were highest during the summer months. Rates in 6-year old meadows were similar to the reference site. This study describes one measure of the return of ecosystem function as seagrass meadows are restored.

Student Poster: 
Yes