Salt Spray and Mineral Cycling in Two California Coastal Ecosystems

Windblown salt aerosols are a significant input to the mineral cycle along coastal areas. Cationic ratios of aerosol salts differ markedly from the same ratios in sea water. Resulting salt inputs to inland ecosystems reflect initial ion separation during sea-water bubble bursting and subsequent fallout of particulate salts until a base-level aerosol concentration is achieved. Inputs of aerosols to Baccharis brushland ecosystems are concentrated in plants and soil. Cations are trapped on leaf surfaces where they are available for foliar absorption and in some cases, translocation. Tracer studies with ^2^2Na indicated that the greatest accumulation of retained ^2^2Na was in the roots of Baccharis plants. Of the total applied dose of ^2^2Na, 12% was either exuded or leached from roots of hydrophonically grown Baccharis over a 25-day period. This phenomenon may be considered a potential pathway for inputs of large amount of Na to soil near shorelines. The surface ionic content of soils reflects nutrient release from litter fall. At 1- to 2-m depths ionic losses from leaching occur in approximately the same ratios as inputs of salt spray. This suggests a steady state with regard to cycling of Na, K, Mg, and Ca.