Molly Schauffler

The postglacial history of three Picea species in New England, USA

Abstract Given the difficulty of separating the three Picea species— P. glauca, P. mariana, and P. rubens (white, black, and red spruce)—in the pollen record, little is known about their unique histories in eastern North America following deglaciation. Here we report the first use of a classification tree analysis (CART) to distinguish pollen grains of these species. It was successfully applied to fossil pollen from eight sites in Maine and one in Massachusetts. We focused on the late glacial/early Holocene (14,000 to 8000 cal yr B.P.) and the late Holocene (1400 cal yr B.P. to present)—the two key periods since deglaciation when Picea has been abundant in the region. The result shows a shift from a Picea forest of P. glauca and P. mariana in the late glacial to a forest of P. rubens and P. mariana in the late Holocene. The small number of P. rubens grains identified from the late glacial/early Holocene samples ( Picea (1000 to 500 cal yr B.P.) was likely the first time since deglaciation that P. rubens was abundant in the region.

Participatory science and education: bringing both views into focus

Aligning the goals of scientists and participants becomes more challenging when citizen science moves into middle- and high-school classrooms. Here, we describe a logic model developed in association with the Acadia Learning Project, a collaboration among scientists, teachers, and students that successfully meets both research and educational needs. The logic model is intended to assist other classroom-based citizen-science initiatives with project design and evaluation.

Interactions between peat and salt-contaminated runoff in Alton Bog, Maine, USA

Abstract Year round, concentrations of base cations (Ca, Mg, Na, and K) and Cl − in surface and groundwater decline exponentially away from Interstate 95, a four-lane asphalt highway which bisects Alton Bog, a poor fen in Penobscot County, Maine, USA. The increased concentrations close to the highway are caused primarily by runoff of road-salt and weathering products of road-bed fill. Concentration ratios, constant with time, between base cations and H + at individual sites suggest that cation exchange reactions between peat and water achieve a state of equilibrium. These ratios change systematically with increasing distance from the highway, indicating systematic changes in the character of the peat exchange surfaces. The major change is a decrease in the occupancy of exchange sites by Na away from the road. These relationships and inferred processes have been duplicated with laboratory experiments. Base saturation of the peat, dominated by Ca, decreases with distance from the highway. Thus, in the short term, peat-water equilibration exerts strong controls on the water chemistry, particularly ion ratios. Long term exposure to elevated concentrations of Ca, Mg, and NaCl in the shallow ground waters has altered the peat chemistry. Availability of plant nutrients (Ca, Mg, and K) has been generally increased by the weathering of road-bed fill and equilibration of the NaCl salt with the peat.

Influence of Vegetational Structure on Capture of Salt and Nutrient Aerosols in a Maine Peatland

Concentrations and fluxes of C1- and Na+ in bulk precipitation and through- fall in an inland, acidic peatland (Alton Bog, Maine, USA) reveal the influence of canopy structure on the deposition rate of road-salt and nutrient-bearing aerosols. Alton Bog borders a four-lane highway that is salted in winter. In open areas of the peatland steep gradients occured in both Cl- and Na+ influxes in bulk precipitation and in surface-water concen- trations within -200 m of the highway. In winter, wooded sites had consistently higher atmospheric influxes of Cl- (up to 4X) than did treeless sites at the same distance from the highway. These results were consistent with expectations based on studies of dry deposition in nonpeatland areas. The increased influx of Cl- at wooded sites implies a significantly higher total influx of nutrients in peatlands where trees occur (especially unevenly spaced trees of mixed heights) than in peatlands with no trees. The effect is likely to be especially important in peatlands that receive all or most incoming nutrients from the atmosphere.