MWC 2005 SPONSORS
U.S. Geological Survey  . Senator George J. Mitchell Center . Maine DHS / Drinking Water Program . Portland Water District . Aqua Maine . Maine Coastal Program / State Planning Office . Maine Dept. of Environmental Protection . Maine Geological Survey . Maine Rural Water Association . Maine Wastewater Control Association . Maine Water Utilities Association . Maine Congress of Lake Associations . Maine Volunteer Lake Monitoring Program . Maine Rivers . University of Maine Cooperative Extension . Maine Sea Grant

2005 Undergraduate Poster Awards

FIRST PLACE

Amanda Haponski, Theresa Hattenrath, Tracy Burke, and Rebecca Beasley
University of Maine at Machias, Machias, Maine

The effects of grazing by Littorina littorea, nutrients, and temperature on benthic microalgal biomass along a salinity gradient in the Machias River, Maine
To test the relative importance of top-down versus bottom-up effects on benthic microalgal concentrations along a salinity gradient typical to northern New England estuaries, we measured benthic chlorophyll-a concentrations under different grazing pressures by the common periwinkle, Littorina littorea, at 3 sites subject to different nutrient concentrations and salinities on the Machias River, Maine. Samples were collected Sep-Nov 2004, to capture variation due to relatively rapid seasonal changes in water temperature common to northern New England. Although water temperatures decreased significantly during the study period, microalgal biomass increased significantly with increasing salinity and nitrate across sites, and neither temperature nor grazing showed a significant effect on chlorophyll-a concentration. These data suggest bottom-up factors in combination with salinity had a greater effect on microalgal biomass than top-down factors during seasonal temperature decline.

HONORABLE MENTION

Ashley Malinowski and Lois K. Ongley
Oak Hill High School, Sabattus, ME

A Point Source of Orthophosphate in the Sabattus Pond (Maine) Watershed?
Sabattus Pond is on the ME DEP Non-point Source Priority Watersheds list. Until this study, no one had attempted to verify anecdotal accounts of a point source of phosphorus in the watershed along the Dead River.

Seven water samples were taken in the Dead River watershed to determine the orthophosphate concentration on Nov. 11, 2004. The samples were sent to the Maine Health and Environmental Testing Laboratory (HETL) for analysis. Above Leeds Junction Road, the aqueous orthophosphate concentrations were below 10 parts per billion (ppb). Below Leeds Junction Road, the concentrations ranged from a peak of 300 ppb near the industrial site decreasing to 16 ppb near the mouth of the Dead River.

Soil samples (150 g dry weight) which were taken at a golf course, at the industrial site, and at an agricultural site, were reacted with 500 mL of distilled water for 21 days. The water was filtered and HETL analyzed those water samples as well. The industrial site soil leached an average of 160 mg of orthophosphate per 150 g of soil; the agricultural site only 0.115 mg/150g soil. The golf course soil leached negligible amounts of phosphorus (0.007 mg/150g soil).
There is a major point source of orthophosphate in the Dead River watershed of Sabattus Pond.
 

2005 Graduate Poster Awards

FIRST PLACE

Melinda Diehl, J. Kahl, K. Webster, I. Fernandez, and S. Norton
1Senator George J. Mitchell Center for Environmental and Watershed Research, University of Maine; 207/581-3233; melinda.diehl@umit.maine.edu
2Center for the Environment, Plymouth State University; 603/535-3179, jskahl@plymouth.edu
3Department of Biological Sciences, University of Maine; 207/581-2542 katherine.webster@umit.maine.edu
5Department of Earth Sciences, University of Maine; 207/581-2156; norton@maine.edu
4Department of Plant, Soil, and Environmental Science, University of Maine; 207/581-2932, ivanjf@maine.edu

Determining Landscape Controls on Surface Water Sulfate Concentrations Using Elevational Transects at the Bear Brook Watersheds in Maine
The Bear Brook Watersheds in Maine (BBWM) provide a unique long-term record of deposition and export of sulfate (SO42-) in two adjacent watersheds, one of which has been experimentally acidified with 1800 eq/ha/yr dry ammonium sulfate ((NH4)2SO4) since 1989. This chemical manipulation mimics acid rain so that the whole ecosystem response to elevated inputs of acidifying chemicals can be evaluated. Intensive monitoring of East (reference) and West (experimental) Bear Brook has produced long-term data on the hydrology and chemistry of precipitation and surface water. Transect samples have been used to interpret the effects of forest type on stream chemistry. The transect sites occur in softwood, mixed, and hardwood stands over 80 m elevation change in both watersheds. East Bear samples increase in SO42- concentration with decreasing elevation, indicating a possible concentrating effect from increasing land area. Preliminary results suggest that the chemical treatment in West Bear has altered the relationship between elevation and SO42- concentration in stream water. Determining the contribution of SO42- to stream water by forest type and watershed area will help define the terrestrial processes that influence the aquatic response to acidic deposition.
 

FIRST PLACE

Jennifer M. Weldon1 and Jean D. MacRae2
1Department of Civil and Environmental Engineering, University of Maine, Orono, ME, 207/581-3401, Jennifer.Stowe@umit.maine.edu
2Department of Civil and Environmental Engineering, University of Maine, Orono, ME, Jean.MacRae@umit.maine.edu

DO MICROBES AFFECT GROUNDWATER ARSENIC CONCENTRATIONS? A STUDY OF IRON AND ARSENIC REDUCING BACTERIA
Arsenic is a contaminant that causes a variety of health effects. Recently the USEPA decreased the maximum contaminant level for arsenic in drinking water from 50 ppb to 10 ppb. In Maine, approximately seventy percent of state residents rely on groundwater sources for their drinking water, with about 40% using private wells. Unfortunately many of these wells contain arsenic concentrations in excess of 10 ppb, and since private wells are unregulated with no requirement for testing, many people may unknowingly be exposed to high arsenic concentrations.

Microorganisms can affect arsenic mobility either directly or indirectly. Our lab has isolated a bacterial strain, NP4 that can directly reduce arsenate. Indirect means of altering arsenic mobility include the reduction of solid phase bedrock materials or coatings that bind arsenic. Iron reducing bacteria such as the genus Geobacter may play a role in the indirect mobilization of arsenic through the loss of binding sites and subsequent release of arsenic into the water. In order to determine if NP4 or Geobacter species have a role in arsenic mobilization, a Fluorescent In-Situ Hybridization (FISH) method was developed to measure their prevalence in groundwater samples.

The FISH method is being used to compare total counts with the NP4 and Geobacter populations. Results indicate that the Geobacter numbers correlate to the groundwater arsenic concentrations in Northport, and Ellsworth ME. The correlation with NP4 is much weaker. This indicates that the Geobacter species may play a significant role in the mobilization of arsenic in groundwater at that site.