Atmospheric fluxes of nutrients onto Singapore Strait

In view of recurring forest fires in Southeast Asia (SEA) on a large scale and the abundant rainfall in this tropical region, atmospheric fallout of airborne particles i.e. dry atmospheric deposition (DAD) and wet atmospheric deposition (WAD) of nutrients to the ocean surface are thought to be significant. Currently, limited data sets of atmospheric deposition (AD) exist for tropical ecosystems in the region. Furthermore, there is a lack of reliable experimental data on AD of nitrogen (N) & phosphorus (P) in tropical environments. It is therefore imperative to quantify the AD of macro-nutrients, N and P species in order to estimate their impacts on aquatic and terrestrial ecosystems. In this study, field measurements of nitrite, nitrate, ammonium, total N (TN), phosphate and total P (TP) were made, in both airborne particulate matter and precipitation, from January 2006 to July 2006 in Singapore. These measurements were done to characterize and estimate the difference between DAD and WAD fluxes of N & P to coastal waters. The estimated loadings from DAD and WAD (g/m²/year) of TN were 1.011±0.441 and 7.052±4.34 and those of TP were 0.187±0.16 and 0.532±0.524, respectively. This investigation represents a baseline study to access environmental effects of AD of nutrients on the coastal aquatic ecosystem.