ATMOSPHERIC DEPOSITION IN MARITIME ENVIRONMENTS AND ITS IMPACT ON TERRESTRIAL ECOSYSTEMS

Seasalts are the dominant chemical constituents of precipitation in ma ritime regions. Dry deposition of these salts is also an important pro cess and consequently, canopy interception by forest ecosystems greatl y augments wet deposition. The separation of seasalt from non-seasalt sulphur is usually accomplished by reference to the concentration rati o of other major component ions of seawater, such as sodium-, chloride -. or magnesium-to sulphate. Biogenic sulphur, from the oceans or from terrestrial ecosystems is sometimes of importance in maritime regions . Seasalts, which dominate atmospheric deposition in maritime regions can induce short-term acidification in surface waters as a result of i on-exchange reactions following storm events. The results of one large storm in western Ireland in 1991 and the recovery process in a peat s oil were clearly discernible in soil water analysis. The seasalt impac t on acid mineral soils can be seen in the exchangeable sodium levels and the degree of base saturation of these soils.