Počet záznamů: 1

Twenty-year inter-annual trends and seasonal variations in precipitation and stream water chemistry at the Bear Brook Watershed in Maine, USA

  1. 1.
    0348967 - GLU-S 2011 RIV NL eng J - Článek v odborném periodiku
    Navrátil, Tomáš - Norton, S. A. - Fernandez, I. J. - Nelson, S. J.
    Twenty-year inter-annual trends and seasonal variations in precipitation and stream water chemistry at the Bear Brook Watershed in Maine, USA.
    Environmental Monitoring and Assessment. Roč. 171, 1/4 (2010), s. 23-45 ISSN 0167-6369
    Výzkumný záměr: CEZ:AV0Z30130516
    Klíčová slova: Bear Brook Watershed in Maine * precipitation chemistry * stream chemistry * seasonality * long-term trends
    Kód oboru RIV: DD - Geochemie
    Impakt faktor: 1.436, rok: 2010

    Mean annual concentrations of SO42- and NO3- in wet-only deposition have decreased between 1988 and 2006 at BBWM due to decreased emissions of SO2 and NOx. Base cations, NH4+ and Cl- concentrations mostly exhibited no trends or statistically significant trends but with change of < 1 ueq L-1 per year from 1988 to 2006. Seasonally, two chemically distinct periods of precipitation (April to September) and (October to March) indicate two different trajectories of air mass movement: dominantly continental sources in the warm season with increased SO42- and NH4+ and mixed continental and marine sources in the cool season with increased inputs of marine aerosols. The major factors driving seasonality of the streams are hydrology, vegetation activity, and temperature. The low flow periods June - October were typical with greater contribution of the deeper flow solutions and increased pH value, anion neutralizing capacity, Si concentration, non-marine Na and low Ali concentrations.
    Trvalý link: http://hdl.handle.net/11104/0189340