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Seasonal Patterns of Dry Deposition at a High‐Elevation Site in the Colorado Rocky Mountains
Author(s) -
Oldani Kaley M.,
Mladenov Natalie,
Williams Mark W.,
Campbell Cari M.,
Lipson David A.
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd026416
Subject(s) - deposition (geology) , biogeochemical cycle , environmental science , nitrogen , arid , cycling , hydrology (agriculture) , nitrate , soil water , ammonium , environmental chemistry , chemistry , ecology , geology , soil science , geography , geomorphology , biology , forestry , geotechnical engineering , organic chemistry , sediment
In the Colorado Rocky Mountains, high‐elevation barren soils are deficient in carbon (C) and phosphorus (P) and enriched in nitrogen (N). The seasonal variability of dry deposition and its contributions to alpine elemental budgets is critical to understanding how dry deposition influences biogeochemical cycling in high‐elevation environments. In this 2 year study, we evaluated dry and wet deposition inputs to the Niwot Ridge Long Term Ecological Research (NWT LTER) site in the Colorado Rocky Mountains. The total organic C flux in wet + dry (including soluble and particulate C) deposition was >30 kg C ha −1 yr −1 and represents a substantial input for this C‐limited environment. Our side‐by‐side comparison of dry deposition collectors with and without marble insert indicated that the insert improved retention of dry deposition by ~28%. Annual average dry deposition fluxes of water‐soluble organic carbon (4.25 kg C ha −1 yr −1 ) and other water‐soluble constituents, including ammonium (0.16 kg NH 4 + ha −1 yr −1 ), nitrate (1.99 kg NO 3 − ha −1 yr −1 ), phosphate (0.08 kg PO 4 3− ha −1 yr −1 ), and sulfate (1.20 kg SO 4 2− ha −1 yr −1 ), were comparable to those in wet deposition, with highest values measured in the summer. Backward trajectory analyses implicate air masses passing through the arid west and Four Corners, USA, as dominant source areas for dry deposition, especially in spring months. Synchronous temporal patterns of deposition observed at the NWT LTER site and a distant Rocky Mountain National Park Clean Air Status and Trends Network site indicate that seasonal dry deposition patterns are regional phenomena with important implications for the larger Rocky Mountain region.