Northeastern Mountain Ponds Geochemistry Compilation 1978-2019

We compiled geochemical data from published, peer-reviewed sources, gray literature, online datasets, unpublished researcher datasets, and our own data from high-elevation ponds and small lakes. Mountain ponds were defined as lakes and ponds situated at elevation >500 m (460 m in the Berkshires), and ponds surface area <60 ha. Many of our data sets are part of the US EPA LTM (Long-Term Monitoring) Network and its predecessor projects (e.g., Maine HELM, ELS-II, various scoping efforts for LTM), and state data repositories. We queried data providers and EPA staff about mountain ponds datasets in the region. We defined the region of interest (“the northeastern US”) as the Northern Appalachian Region, plus the Adirondack Mountains in New York State, ranging from latitude 42◦–46◦ north and longitude 75◦–69◦ west. We classified ponds into their respective mountain regions within Level II Ecoregion 58 – Northern Highlands, within Eastern Temperate Forest: Western Mountains (Maine’s Mahoosuc and White Mountains, to the terminus of the Appalachian Trail in Baxter State Park); White Mountains (in New Hampshire); Green Mountains (in Vermont); Berkshires (Western Massachusetts), and Adirondacks (in Adirondack Park, NY), to aid in sub-regional comparisons and statistical trend analyses.