Solute deposition from cloud water to the canopy of a puerto rican montane forest

Abstract

Deposition of cloud water and dissolved solutes onto vegetation was studied by sampling clouds, throughfall and stemflow during 12 cloud-only events at Pico Del Este, a tropical cloud forest in the Luquillo Mountains 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 epiphyte-laden vegetation. Elemental deposition by cloud water was similar to that in other, more polluted sites, but was only 8–30% of total deposition (cloud-only plus rain) due to the high rainfall at the site (approximately 5 m). Na and CI from marine aerosols dominated cloud chemistry, with concentrations of 400 μeqδ −1 . Sulfate and nitrate concentrations were 180 and 60 μedδ −1 , respectively. After passage through the canopy, concentrations of base cations in deposited cloud water increased, and concentrations of nitrogen decreased.