Inferring regional patterns and responses in nitrogen and mercury biogeochemistry using two sets of gauged paired-watersheds


Principal Investigator:

  Steve Kahl
Senator George J. Mitchell Center for Environmental & Watershed Research
102 Norman Smith Hall
University of Maine
Orono, ME
Phone: (207) 581-3244
FAX: (207) 581-2725
Ivan Fernandez, University of Maine
Stephen Norton, University of Maine
Bruce Wiersma, University of Maine
George Jacobson, University of Maine
David Manski, Acadia National Park
Terry Haines, USGS-BRD
Lindsey Rustad, USDA-Forest Service
Charles Roman, USGS-BRD
Robert Lent, USGS-WRD

Park: Acadia National Park


Project Summary:

This project is part of long-term ecological research using two gauged-watersheds to be imple-mented at Acadia National Park through collaborative funding by USGS and this proposal to EPA. The focus of this request is atmospheric deposition of nitrogen (N) and mercury (Hg), and their ecological consequences. Both elements are of major concern, both regionally and to the Park Service at Acadia. This location offers the advantages of a) co-funding for cost-effectiveness; b) a natural experimental design for the two watersheds because of a major forest fire in part of the Park in 1947; c) parallel design with the acidic deposition experiment on paired-watersheds at the nearby Bear Brook Watershed, Maine (BBWM); and d) prior research at Acadia and BBWM that supply background data, and provide the basis for ecosystem indicators to be applied at Acadia. Our objectives will address N cycling and saturation, and Hg input and bioavailability, in paired watersheds with different forest types. We will use the natural landscape contrasts provided by fire to compare patterns and processes in N and Hg sequestration and mobility. Nitrogen loading to estuaries will be addressed by periodic sampling of estuary tributaries as "satellite" locations, whose N loading will be extrapolated from occasional sampling by using the more intensively monitored main watersheds as index sites.

Our approach will involve using input/output measurements at the watershed scale to define the unknowns of Hg inputs to landscapes, determine locations and processes of Hg speciation, resolve the status of N retention, and estimate N loading to selected estuaries that have prior background data. We will determine the relative input of Hg and methyl-Hg from wet deposition, throughfall and litterfall. The expected results will provide new information for Acadia and for the New England region on the ecological consequences of high N deposition at Acadia, and the loading of N to estuaries in the region. We lack an explanation of the high accumulation rates of Hg in sediment and peat cores compared to wet-only deposition, and have not explained why Acadia has some of the highest Hg concentrations in biota in the world. The general repres-entativeness of Acadia forests for the New England region, combined with the fire history to be included in our experimental design (fire also being "typical" of the historical New England landscape), offers the opportunity to understand some key issues for Acadia, while providing insight into these issues at the regional scale.


Final Report

Correlating predictive contaminant deposition maps with streamwater chemistry at Acadia National Park (Abstract)

2002 Acadia PRIMENet Meeting Presentation

Paleoecological Assessment of Forest Disturbance in Upper Hadlock Brook and Upper Cadillac Brook Watersheds
by M. Schauffler, S. Nelson, K. Johnson, J.Kahl and G. Jacobson.

Determining Atmospheric Deposition Inputs to Two Small Watersheds at Acadia National Park by S.J. Nelson (APPENDICES)

A Semi-Annual Progress Report for this project is available.

2001 PRIMENet Meeting Presentation: Mercury and Methylmercury Dynamics in a Pair of Watersheds at Acadia National Park (Kenneth B. Johnson, Terry Haines, Steve Kahl, Steve Norton)

2000 PRIMENet Meeting Presentation: Inferring regional patterns and responses in N and Hg biogeochemistry using gauged paired watersheds and Acadia National Park (Steve Kahl)

Closing the Loop on Hydrologic and Mass Balances for a Temperate Forested Park by S.J. Nelson

Twenty years of surface water chemistry: How does Acadia National Park fit into the regional response (S. Kahl, S. J. Nelson, J. L. Stoddard, S. A. Norton, T. A. Haines)



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