Presenting at Geological Conference – Hobart and William Smith Colleges \
The HWS Update

Presenting at Geological Conference

Seniors Emily Cummings ’12 and Maggie Stewart ’12 recently presented summer research they conducted under the direction of Professor of Geoscience John Halfman at the Annual Meeting of the Geological Society of America, in Minneapolis, Minn.  At the same conference, alums April Abbott ’09 and Andrea Rocchio ’11 presented follow up work to research they each conducted with Associate Professor and Chair of the Geoscience Department Tara Curtin. Benjamin Spencer ’11 prepared a paper for the conference but was ultimately unable to attend. All five conducted research on one or more of the Finger Lakes, collecting and analyzing samples from the lakes themselves or their watersheds. Approximately 6,000 scientists attended the conference.

Cummings’ project with Halfman was titled “Nutrient Loading in the Owasco Lake Watershed: Results from an Autonomous Sampler, R2D2.”  Owasco Lake is a source of drinking water for approximately 44,000 residents and supports an agricultural and tourism based economy. The lake has a residence time of one to three years, suggesting that it may be quickly influenced by runoff from precipitation events. Cummings and Halfman installed a portable water sampler near Dutch Hollow Brook on Owasco Lake to quantify nutrient fluxes to the lake and relative contributions of event and base-flow conditions. Runoff from agricultural land is a major non- point source in the Owasco watershed. Continued monitoring of Dutch Hollow through the fall will hopefully provide a robust dataset of additional event and other variations, and enable the calculation of annual nutrient loads to the lake. The researchers anticipate that the results may dictate future mitigation and remediation efforts.

Stewart presented “Identification of Nutrient Sources in Two Owasco Lake Tributaries.” Two streams, Dutch Hollow Brook and Owasco Inlet which collectively drain 70 percent of the watershed, were sampled to delineate point and non-point sources and other factors affecting delivery of nutrients to the lake. Identification of pollutant sources would dictate mitigation and remediation efforts to improve water quality in the lake. Runoff from agricultural land is a major non-point source in the Owasco watershed. Stewart and Halfman suggested that Owasco Lake residents support mitigation and remediation within this tributary’s watershed to see if nutrient loading is reduced in the future.

Abbott presented “Historic Mercury Deposition in Two New York Finger Lakes.” Abbott and Curtin documented changes in mercury loading to Seneca Lake and Owasco Lake over the past 200 years. Mercury fluxes to the lakes were affected by not only atmospheric emissions, but also sediment transport from the watershed, largely as a result of changes in land use practices. An increase in mercury concentration in the lake sediment is coincident with an increase in the land area used for agriculture in both watersheds.  Historic industry (e.g., tanneries, paper mills) along waterways that fed the lakes may have also contributed some mercury.

Rocchio presented, “Phosphorus Cycling and the Effectiveness of Recent Alum Treatments in Honeoye Lake, N.Y.,” part of her independent study with Curtin during her senior year. She also was awarded funds from the Rochester Academy of Science and Sigma Xi to support her independent study research project with Curtin this past academic year. Despite the increase in phosphorous (P) retention by the sediment as the result of recent alum treatments to the lake, P levels in the lake water column continue to increase, likely as a result of external P-loading via runoff and stream influx.

Spencer’s paper is the culmination of years of work and his independent study with Curtin this past spring 2011. In their paper, “Post-Glacial Relatiev Lake Level Fluctuations in the Seneca Lake Basin, N.Y.,” Spencer and Curtin investigated how lake level in Seneca Lake varied over the past 14,000 years as a result of the changing position of the retreating Laurentide ice sheet, river outlet position, post-glacial isostatic rebound, and hydrologic budget.  They proposed that isostatic rebound played a larger role in changing lake level than previously recognized and found that post-glacial isostatic rebound, not climate, drove large-scale (10s of meters) changes in lake level.

In the photo above Emily Cummings ’12 and Maggie Stewart ’12 are pictured with Professor John Halfman.