Department or Program

Environmental Studies


This study aimed to provide preliminary insight as to what prevalent microorganisms reside within the Lake Auburn Watershed. Lake Auburn is a pristine public water source which supplies water to over 60,000 people within the twin cities of Lewiston and Auburn. Lake Auburn has earned a filtration waiver since 1991 due to continual exemplary water quality. To maintain the waiver, in-lake turbidity concentrations must remain less than 5 NTU and faecal coliform concentrations cannot be more than 20 col/100mL. Aside from legally testing for faecal coliforms, there is no knowledge on the other microbial inhabitants of the lake. Regulations are installed to upkeep water quality, however outside of the town of Auburn’s jurisdiction these zoning ordinances and regulations change. As microbial community structure is heavily influenced by environmental variables, including chemical water properties and surrounding land use, sites were chosen based on difference in surrounding land use along the Basin, the major tributary of Lake Auburn. Using q-PCR, the relative abundance of 13 targeted microorganisms across bacteria, protozoa, and viral taxa was detected. Urban, forested, and agricultural land uses had observed effects on both richness and diversity. Storm events and precipitation largely influenced community diversity and abundance through dilution, runoff, and introduction. Nutrient availability did not have a significant effect on community composition. Community structure varied dramatically in response to biogeochemical differences within each site’s sub-watershed. This study provided wide-spread preliminary results on the relative abundances of different microorganisms and provokes a variety of topics for further investigation.

Level of Access

Restricted: Campus/Bates Community Only Access

First Advisor

Holly Ewing

Date of Graduation


Degree Name

Bachelor of Arts

Number of Pages



Available to Bates community via local IP address or Bates login.