Location

Parker-Reed, SSWAC

Start Date

1-5-2014 10:00 AM

End Date

1-5-2014 11:00 AM

Project Type

Poster- Restricted to Campus Access

Description

Temperate lakes are often phosphorus(P)-limited, in contrast to stream ecosystems that are often nitrogen(N)-limited. However, patterns of nutrient limitation across these ecosystem types are rarely compared directly within the same watershed. The Belgrade Lakes watershed in central Maine, comprised of seven interconnected lakes of differing trophic states, provides a unique ecosystem of study. We determined nutrient limitation in four streams using nutrient diffusing substrata (NDS) for stream biofilms and in five lakes using an analogous water-column bioassay for lake phytoplankton. In both methods, we used a control and treated samples with additions of phosphate (PO4-), nitrate (NO3-), ammonium (NH4+), and both NH4+ and PO4-. We hypothesized that streams would be N-limited, while the lakes would be P-limited. Nutrient limitation in the streams was largely site specific: two sites exhibited no limitation, two were co-limited, one P-limited, and one N-limited. This suggests that shoreline nutrient inputs from landscape runoff could have more of an impact on stream biofilm growth than nutrients from upstream water bodies, and highlights the importance of homeowner education about buffers and other watershed-friendly environmental practices.

Sponsoring Department

Colby College. Environmental Studies Program

CLAS Field of Study

Interdisciplinary Studies

Event Website

http://www.colby.edu/clas

ID

192

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May 1st, 10:00 AM May 1st, 11:00 AM

Patterns of Nutrient Limitation in Streams and Lakes of the Belgrade Lakes Watershed: Comparisons Across Ecosystems and Trophic States

Parker-Reed, SSWAC

Temperate lakes are often phosphorus(P)-limited, in contrast to stream ecosystems that are often nitrogen(N)-limited. However, patterns of nutrient limitation across these ecosystem types are rarely compared directly within the same watershed. The Belgrade Lakes watershed in central Maine, comprised of seven interconnected lakes of differing trophic states, provides a unique ecosystem of study. We determined nutrient limitation in four streams using nutrient diffusing substrata (NDS) for stream biofilms and in five lakes using an analogous water-column bioassay for lake phytoplankton. In both methods, we used a control and treated samples with additions of phosphate (PO4-), nitrate (NO3-), ammonium (NH4+), and both NH4+ and PO4-. We hypothesized that streams would be N-limited, while the lakes would be P-limited. Nutrient limitation in the streams was largely site specific: two sites exhibited no limitation, two were co-limited, one P-limited, and one N-limited. This suggests that shoreline nutrient inputs from landscape runoff could have more of an impact on stream biofilm growth than nutrients from upstream water bodies, and highlights the importance of homeowner education about buffers and other watershed-friendly environmental practices.

http://digitalcommons.colby.edu/clas/2014/program/350