SOLUTE DEPOSITION FROM CLOUD-WATER TO THE CANOPY OF A PUERTO-RICAN MONTANE FOREST

Deposition of cloud water and dissolved solutes onto vegetation was st udied by sampling clouds, throughfall and stemflow during 12 cloud-onl y events at Pico Del Este, a tropical cloud forest in the Luquillo Mou ntains of Puerto Rico. Liquid water content of the sampled clouds was low (0.016 g m-3), but deposition of water (1.3 mm d-1) was comparable to other sites, apparently due to efficient capture of clouds by epip hyte-laden vegetation. Elemental deposition by cloud water was similar to that in other, more polluted sites, but was only 8-30% of total de position (cloud-only plus rain) due to the high rainfall at the site ( approximately 5 m). Na and Cl from marine aerosols dominated cloud che mistry, with concentrations of 400 mueq l-1. Sulfate and nitrate conce ntrations were 180 and 60 mueq l-1, respectively. After passage throug h the canopy, concentrations of base cations in deposited cloud water increased, and concentrations of nitrogen decreased.