A Population Genetic Study of the Zostera marina (eelgrass) Ecotypes of Barnegat Bay, New Jersey and Implications for Grass Bed Restoration
Date of Award
Master of Science (MS)
College of Science and Mathematics
Thesis Sponsor/Dissertation Chair/Project Chair
Zostera marina is a species of seagrass widely found in the northern Atlantic and northern Pacific Oceans. It is primarily a cold-water adapted plant that is capable of both sexual and asexual reproduction. Zostera marina serves many ecological roles, including stabilizing sediments, reducing current velocity, preventing erosion and providing food and shelter to many organisms. Eelgrass populations have suffered numerous large-scale declines due to both natural as well as human-induced causes. Specifically within Bamegat Bay, New Jersey, the Z. marina populations have declined by over 62% within the past 20 years. Restoration efforts have had diverse growth and survival rates, with some restoration sites that showed significant survival; while others displayed very little or no survival. These differences may be due to the stock origin of the plants. We completed a microsatellite-based genetic investigation of eight populations of Z. marina within Bamegat Bay, New Jersey in order to examine the relationship between different ecotype conditions and genetic diversity. In addition, we wanted to assess how genetic variation may enhance restoration success for Zostera marina. Eelgrass populations from Long Island, New York, Chesapeake Bay, Virginia and Egg Island, Alaska were also investigated. The results from this study suggest that the Long Island population has low levels of genetic diversity, as seen in the few numbers of alleles, low observed heterozygosities and low effective population size. The Oyster Creek, Marsh Elder and Ham Island populations continually clade together in our phylogenetic trees and experience higher levels of expected gene flow. These populations are under similar heat and light stresses, suggesting a common selective pressure and possibly a close genetic relationship. The Oyster Creek population also had the largest measurable effective population size, which suggests a high level of genetic diversity despite the heat disturbance. Because this population appears to have a large amount of genetic variation, Oyster Creek may be a good candidate population to use for the stock origin of plants for future restoration of declining Zostera marina populations.
Smith, Stephanie Marie, "A Population Genetic Study of the Zostera marina (eelgrass) Ecotypes of Barnegat Bay, New Jersey and Implications for Grass Bed Restoration" (2007). Theses, Dissertations and Culminating Projects. 1268.