DETERMINING NITROGEN INPUTS TO THE MOHAWK RIVER AND ITS WATERSHED BY SYNTHESIZING BIOGEOCHEMISTRY, FECAL SOURCE TRACKING, AND GEOSPATIAL ANALYSIS

The Mohawk River (Teionontatátie) flows along the Erie Canal through upstate New York and is the largest tributary to the Hudson. Given the widespread use of the river and its tributaries for drinking water, sanitation, and recreation, it is critical to understand the drivers of water quality throughout the Mohawk watershed, which is predominantly forested or agricultural but also includes significant urban inputs. Our focus is on nitrogen (N), an understudied aspect of Mohawk River water quality that has effects on productivity, eutrophication, and toxic algal blooms. Data from the river, tributaries, and nearby lakes indicate high N throughout much of this watershed, with elevated nitrate in waters draining agricultural land and higher levels of ammonium and urea near urban sources. To further quantify nutrient sources, we synthesized nutrient data with qPCR-based human and cattle fecal source tracking, as well as geospatial data on land use/land cover. Unlike nearby lake sites, the majority of river and stream samples had nitrogen to phosphorus (N:P) ratios above the Redfield ratio, indicating a more thorough analysis of nutrient limitation is warranted. Microbial sequence data shows numerous stretches of the Mohawk River and tributary creeks contain significant communities of cyanobacteria, including many families with known toxic species. These data suggest numerous N sources are sustaining elevated N concentrations in the Mohawk River and allow us to pinpoint sources of specific N compounds, linking water quality to surrounding land use.

Primary Presenter: Lilianna Gross, Hamilton College (Liliannaxg3@gmail.com)

Authors:

Lilianna Gross, Hamilton College  (Lxgross@hamilton.edu)

Julian Damashek, Hamilton College  (jdamashe@hamilton.edu)