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Following African dust into the forest; Impacts on rainfall and throughfall components

Following African dust into the forest; Impacts on rainfall and throughfall components.

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Following African dust into the forest; Impacts on rainfall and throughfall components

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  1. Following African dust into the forest; Impacts on rainfall and throughfall components

  2. Throughfall and rainfall flux of cations (Ca, Mg, K and Na) during 15 years. Volcanic activity periods are identified when ash clouds of 1800 m (6000 ft) or more were produced in Soufrière Hills volcano, Montserrat, after 1995. Black lines represent the mean value.

  3. Throughfall fluxes kg ha-1d-1during volcanic activity in Montserrat. Fluxes for *NH4-N, *NO3-N, and *PO4-P are g ha-1d-1. Significant differences in flux between periods of volcanic and non-volcanic activity are represented by .

  4. Location: luq.lternet.edu / data / Meteorology, Nutrient and Carbon Dynamics LTERDBAS 20 Chemistry of rainfall, throughfall and stream water from El Verde and Bisley LTERDBAS 148 Bisley rainfall and throughfall, and chemistry of rainfall and throughfall USDA-FS International Institute of Tropical ForestryAnalytical Chemistry Lab Please contact Ariel Lugo or Mary J. Sanchez , Lab Director USDA Forest Service International Institute of Tropical Forestry Jardín Botánico Sur 1201 Calle Ceiba Rio Piedras, PR 00926 787-766-5335

  5. Rainfall • Saharan dust events contributed 60% of the total annual Ca • Activity of Caribbean volcanoes • increased TDN, most nutrients came through dry deposition • and a decrease in pH values was observed Throughfall • Saharan dust contributes 50% of the total annual Ca • Activity of Caribbean volcanoes • increased TDN, NH4-N, PO4-P, DOC, SO4-S • decreased pH • Contributed a net enrichment of nutrients • Under the canopy pH values are buffered

  6. In Summary Rainfall, canopy processes, and throughfall • Although the forest changed dramatically after Hugo, these changes were not reflected in throughfall chemistry • The similarity between Bisley and other tropical sites suggests that biological processes that occur within the canopy and leaf surface are more important than canopy species composition to influence throughfall nutrients in diverse forests • Over a period of storms, droughts, and successional change, throughfall nutrient fluxes and patterns were stable and resilient • This indicates that physical and biological processes associated with water passing through the canopy buffer the forest’s internal nutrient cycles from external variations in rainfall inputs

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