Characterization of dissolved organic matter in a eutrophic coastal lagoon
Mentor 1
Laodong Guo
Start Date
16-4-2021 12:00 AM
Description
Veterans Park Lagoon, a closed ecosystem near the Milwaukee Harbor belonging to the coastal system of Lake Michigan has shown evidence of increased levels of eutrophication, or a richness of nutrients and minerals. Determinants of the levels of eutrophication in coastal lagoons include the seasonal cyanobacterial blooms and their respective causality in increased nutrient levels. For this study, weekly water samples were collected from the lagoon from June 2019 to October 2019. The filtered samples were then run through a fluorescence spectrophotometer and a UV–Visible spectrophotometer. The parameters used for this study fall into the category of dissolved organic matter (DOM). Measurements of components such as chlorophyll-a, dissolved organic carbon (DOC), colored dissolved organic matter (CDOM), and humification contribute to quantitative and qualitative findings. Results show that seasonal variability and its effect on water temperature cause changes in these levels. In comparison to its neighbor, Lake Michigan, Veterans Park Lagoon has a larger euphotic zone, causing more light penetration and therefore, higher levels of CDOM within the bulk DOM. The aromatic humic components of DOM allow for fluorescence as they absorb the UV light and we expect a high DOM level in this lagoon because of the large quantity of algal biomass present. Additionally, the positive relationship between seasonal transitions and biomass levels exemplify parameters in which we can further explore the effects of dissolved organic matter on an increased prevalence of nutrient pollution. Other occurrences such as precipitation, surface runoff, and recreational use also affect algal biomass and water quality. Long term observation of these parameters and others may lend some insight into the relationships detected and the overall health of this unique body of water.
Characterization of dissolved organic matter in a eutrophic coastal lagoon
Veterans Park Lagoon, a closed ecosystem near the Milwaukee Harbor belonging to the coastal system of Lake Michigan has shown evidence of increased levels of eutrophication, or a richness of nutrients and minerals. Determinants of the levels of eutrophication in coastal lagoons include the seasonal cyanobacterial blooms and their respective causality in increased nutrient levels. For this study, weekly water samples were collected from the lagoon from June 2019 to October 2019. The filtered samples were then run through a fluorescence spectrophotometer and a UV–Visible spectrophotometer. The parameters used for this study fall into the category of dissolved organic matter (DOM). Measurements of components such as chlorophyll-a, dissolved organic carbon (DOC), colored dissolved organic matter (CDOM), and humification contribute to quantitative and qualitative findings. Results show that seasonal variability and its effect on water temperature cause changes in these levels. In comparison to its neighbor, Lake Michigan, Veterans Park Lagoon has a larger euphotic zone, causing more light penetration and therefore, higher levels of CDOM within the bulk DOM. The aromatic humic components of DOM allow for fluorescence as they absorb the UV light and we expect a high DOM level in this lagoon because of the large quantity of algal biomass present. Additionally, the positive relationship between seasonal transitions and biomass levels exemplify parameters in which we can further explore the effects of dissolved organic matter on an increased prevalence of nutrient pollution. Other occurrences such as precipitation, surface runoff, and recreational use also affect algal biomass and water quality. Long term observation of these parameters and others may lend some insight into the relationships detected and the overall health of this unique body of water.
