Cloudwater deposition its a source of fixed nitrogen in a Hawaiian montaneforest

Precipitation, dry deposition, and cloud water deposition of fixed nitrogen (nitrate and ammonium ions) were measured on the Island of Hawaii. The fir st two were small N inputs, averaging 0.6+/-0.2 and 0.15+/-0.08 kg N ha(-1) yr(-1) respectively. We estimate cloud water deposition to be 8-22 kg inor ganic N ha(-1) yr(-1). If an estimate of organic N is included, it may be a s high as 50 kg N ha(-1) yr(-1). Additionally, cloud water deposition is of hydrological significance as it comprised 37% of the total water input. Cl oud water interception was certainly lower in the past, as the developing e cosystem would have had less collection surface area. Cloud water samples that were associated with volcanic haze events were ver y concentrated in NO3- and constituted 60% of the annual cloud water N depo sition. This NO3- probably originated from atmospheric N fixed thermally at the hot lava surface or from an interaction between lava and the ocean. If volcanically influenced samples are excluded from the analysis, the result ing cloud water deposition would have been 4-9 kg N ha(-1) yr(-1). The Paci fic Ocean and Kilauea volcano may have a profound impact on the development of this terrestrial ecosystem, as sources of fixed nitrogen.