BACKGROUND
Watersheds of the Adirondack Mountains receive high levels of acid deposition resulting from atmospheric emissions of nitrogen and sulfur oxides. Acidic deposition has been shown to reduce acid neutralizing capacity (ANC) and calcium (Ca) concentrations, and increase acidity and aluminum (Al) concentrations in soils and surface waters, and affect forest health as well as fish and macroinvertebrate assemblages across the region.
The U.S. Environmental Protection Agency (EPA) is currently developing secondary standards for nitrogen and sulfur emissions that will indirectly protect terrestrial and aquatic species and their communities from further adverse impacts and promote recovery of acidified ecosystems to an un-impaired or, at least, some acceptable condition/level. These standards will rely heavily on critical loads (CL) research which estimates threshold or target deposition loads of nitrogen and sulfur to watersheds, below which significant harmful effects on sensitive elements of terrestrial and (or) aquatic ecosystems should not occur. A number of acid-base chemistry parameters such as pH, ANC, and inorganic monomeric aluminum (Ali) have comparable effect thresholds for selected aquatic and terrestrial species, which when exceeded, can impair their health, cause mortality, reduce population density, shift species distributions, and decrease overall community diversity.
A recently initiated New York CLs study (being undertaken by Syracuse University, USGS, E&S Environmental Chemistry; NYSERDA Agmts. 73402, 73402A and 73402B) is assessing CLs for acidification and recovery by conducting site-specific model simulations of past acidification and future projections of recovery of stream ecosystems, and using these model results to extrapolate potential recovery of the broader population of Adirondack streams. The project plans to assess the findings within the context of Adirondack lake recovery.
However, the relations among (a) nitrogen and sulfur emission (and deposition) levels, (b) acid-base chemistry, and (c) terrestrial and aquatic species, and (d) species assemblages (population and/or community metrics) are complicated, regionally variable, and difficult to characterize. A better understanding of the relations between acid-base chemistry and various biological responses is needed to formulate critical target loads for nitrogen and sulfur deposition that will protect natural ecosystems. Acid-base chemistry and biological data from long-term chemistry and biology monitoring programs in the Adirondack region could help define or refine an assortment of biological-response models that are needed to evaluate, postulate, and/or verify critical (target) nitrogen and sulfur deposition loads that are protective of local and regional stream ecosystems.
OBJECTIVES
The primary objective of this study is to increase our understanding of the relations between acid-base chemistry and the condition of fish and macroinvertebrate assemblages in lakes and streams of the Adirondack Mountain region, which is needed for current Critical Loads analyses. The USGS plans to compile and analyze chemical and biological data from multiple datasets and evaluate changes in biological assemblage and abundance in streams and lakes resulting from changes in acid-base chemistry. This work will support the recently initiated New York CL’s project (NYSERDA Agmts. 73402, 73402A and 73402B).
APPROACH
Several datasets have been compiled over the past three decades by various agencies. The Adirondack Lakes Survey Corporation (ALSC) assessed sampled water chemistry and fish assemblages in nearly 1469 lakes during the mid 1980’s. The USGS and ALSC assessed high and low-flow chemistry of nearly 400 Adirondack streams 3-to-5 times as part of the Western Adirondacks Stream Survey (WASS) and East-Central Adirondacks Stream Survey (ECASS) between 2003 and 2015. The N.Y. Department of Environmental Conservation (DEC) and USGS inventoried macroinvertebrate assemblages at 80 of the 400 stream sites over the same period, and during 2014 and 2015 the USGS quantified fish assemblages at 40 of 200 WASS sites, and at 14 additional Western Adirondack streams, first surveyed during the 1970s and 80s.
The USGS plans to compile and organize parallel biological and chemical datasets from these efforts for analysis. Key components of each of these datasets shall be: (1) stream macroinvertebrate-sample site, date, community metrics, and species relative-abundance data; (2) stream fish-sample site, date, community metrics, and species abundance data; (3) stream chemistry data that match or are close to each fishery and macroinvertebrate survey date; (4) lake fish-sample site, date, community metrics, and species abundance data; and (5) lake chemistry data that correspond to with fishery survey date.
Following data compilation and organization, the USGS plans to:
1. Develop empirical relationships between chemical indicators of acidification stress (e.g., pH, ANC, total aluminum, Ali, Base Cation Surplus (BCS), calcium, and others) and key fish and macroinvertebrate community metrics (e.g., species absence/presence, relative abundance, richness, and diversity) in lakes and streams;
2. Examine these relations for significant thresholds causing effects on key community metrics and/or species assemblages using change point analysis;
3. Identify the range of responses that key biological characters exhibit in lakes and streams of the Adirondack Mountains that are affected by acidification, or which are expected to recover from decreased acidification.
The USGS will provide the results of this analysis to the companion New York CLs study. These algorithms will then be used by the New York CLs study team to evaluate how acidification has currently impacted biota of Adirondack Mountain lakes and streams as well as to predict the timing of additional changes (based upon future acid deposition scenarios) and forecast how changes in lake and stream chemistry (resulting from various target loads at different time steps) may support recovery of biological communities in surface waters of the Adirondack region. These field-based models or algorithms may also help inform the EPA’s Integrated Plan for Review of the Secondary National Ambient Air Quality Standards (NAAQS) for the Effects of Sulfur Oxides (SOx) and Nitrogen Oxides (NOx) on Ecosystems.
Project
Location by County
Adirondack Region: Clinton County, NY, Essex County, NY, Franklin
County, NY, Fulton County, NY, Hamilton County, NY, Herkimer County, NY , Lewis
County, NY, Oneida County, NY, Saint Lawrence County, NY, Saratoga County, NY,
Warren County, NY, Washington County, NY
