Cloudwater deposition its a source of fixed nitrogen in a Hawaiian montane forest

Precipitation, dry deposition, and cloud water deposition of fixed nitrogen (nitrate and ammonium ions) were measured on the Island of Hawaii. The first 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 inorganic N ha(-1) yr(-1). If an estimate of organic N is included, it may be as 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. Cloud water interception was certainly lower in the past, as the developing ecosystem would have had less collection surface area. Cloud water samples that were associated with volcanic haze events were very concentrated in NO3- and constituted 60% of the annual cloud water N deposition. 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 resulting cloud water deposition would have been 4-9 kg N ha(-1) yr(-1). The Pacific Ocean and Kilauea volcano may have a profound impact on the development of this terrestrial ecosystem, as sources of fixed nitrogen.