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IMPACTS OF MARINE AEROSOLS ON SURFACE WATER CHEMISTRY AT BEAR BROOK WATERSHED, MAINE USA
Citation:
NORTON, S. A. AND J. S. KAHL. IMPACTS OF MARINE AEROSOLS ON SURFACE WATER CHEMISTRY AT BEAR BROOK WATERSHED, MAINE USA. Verdhandlungen Internationale Vereinigung fur Limnologie (verh. Ingernat. Verein. Limnol.). E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany, 27:1280-1284, (2001).
Impact/Purpose:
To study possible acidification of streams from marine aerosols
Description:
The East Bear catchment at Bear Brook Watershed, Maine receives moderate (for the eastern U.S.) amounts of Cl- in wet and dry deposition. In 1989, Cl- in precipitation ranged from 2 to 55 eq/L. Dry, occult, and wet deposition plus evapotranspiration resulted in stream Cl- averaging more than 200% higher than wet precipitation. The atmospheric deposition was relatively high in cooler months. Because of water and marine salt storage in and release from the unsaturated and saturated zones of the soils, the concentration of Cl- in the stream ranged only from about 50 to 100 eq/L. The base cations from the marine aerosols comprised 34% of the export of the sum of Ca, K, Mg, and Na. Soils were in approximate cation exchange equilibrium with the stream water and the 1989 atmospheric loading of marine aerosols. Seasonal variations in stream chemistry suggest that Na+ is preferentially adsorbed by soils in the cooler months and leached during the late spring and summer. This seasonal retention of Na was compensated dominantly by a reciprocal relationship with Ca. Episodic acidification from marine aerosols was relatively unimportant because of internal damping of variations in precipitation quality and quantity.