Fog and acidification impacts on ion budgets of basins in Nova Scotia, Canada

We examined hydrogeochemical records for a dozen watersheds in and near Kej imkujik National Park in southwestern Nova Scotia by relating stream ion co ncentrations and fluxes to atmospheric deposition, stream type (lake inlet versus outlet; brown versus clear water), and watershed type (catchment are a, topography, soils, and dominant forest cover type). We found that fog an d dry deposition make important contributions to S, N, Cl, H, Ca, Mg, K, an d Na inputs into these watersheds. Seasalt chloride deposition from rain, s now, fog, and dry deposition equal total stream outputs on a region-wide ba sis. Chloride outputs, however, differ among watersheds by a factor of abou t two, likely due to local differences in air now and vegetational fog inte rception. We found that most of the incoming N is absorbed by the vegetatio n, as stream water NO3- and NH4+ are very low. Our results also show that t he vegetation and the soils absorb about half of the incoming SO4-2. In com parison with other North American watersheds with similar forest vegetation , Ca outputs are low, while Mg and K outputs are similar to other regions. Soil exchangeable Ca and soil cation exchange capacity are also very low. W e found that first-order forest streams with no upstream lakes have a disti nct seasonal pattern that neither corresponds with the seasonal pattern of atmospheric deposition, nor with the seasonal pattern of downstream lake ou tlets.