Bachelor of Arts
Biological and Physical Sciences
Program or Major
Wetlands are critical ecosystems that are inhabited by an incredible diversity of organisms, but they are threatened by human activity. Water chemistry testing and bioindicators are two methods for monitoring wetland health. Desmids belong to an order of unicellular, microscopic green algae that live in freshwater habitats, including wetlands. The role of desmids as bioindicators for water quality has been studied due to desmids' narrow ecological range, sensitivity to changes in the environment, and morphological diversity. The function of desmids as bioindicators in New England has not been studied thoroughly. This project examined the relationship between the desmid communities and environmental factors of New England wetlands. Desmid samples were collected from fourteen wetlands in southern and northern New Hampshire and one wetland in Massachusetts. The environmental factors measured at the sites were conductivity, pH, shoreline length, total wetland area, unvegetated open water area, percent vegetation cover. The relationships between the diversity of the desmid communities and the water chemistry measurements at the sites were examined with correlation and regression analyses. The relations between sites were evaluated with similarity indices based on desmid community composition. Canonical correspondence analysis was performed to determine which environmental factors explained the greatest amount of variation in the desmid community composition. A total of 243 desmid species belonging to 23 genera were observed across all sites. The highest desmid diversity was observed at Fourth Connecticut Lake, a remote site in Pittsburg, NH, where 109 desmid species belonging to 18 genera were recorded. A diversity of desmid communities was found at sites throughout southern and northern New Hampshire and the desmid communities displayed sensitivity to environmental conditions. Similar to results of other studies, the results of this study suggest that desmid communities may be influenced by pH. There was a negative relationship between the number of desmid genera and pH, indicating that the number of desmid genera at the sites decreased with increasing pH. Conductivity, percent vegetation cover, and pH were the most important environmental factors in explaining the variation in desmid community composition of the sites. However, the environmental factors in this study did not fully explain differences in desmid diversity and community composition among sites. Further research of the desmid communities in New England with a larger sample size, a wider range of water chemistry measurements, and additional environmental factors is necessary to understand the relationship between desmid communities and environmental conditions. Desmids as bioindicators would offer a valuable opportunity to monitor wetland health through citizen science projects and raise of awareness of the importance of wetlands.
Magner, Mollie, "Desmid Communities and Environmental Conditions of New England Wetlands" (2022). Honors Theses. 109.