The impact of eutrophication towards selected bacterial process rates in tropical coastal waters

The dissolved organic nutrient conditions and bacterial process rates at two tropical coastal sites in Peninsular Malaysia (Port Klang and Port Dickson) were initially studied in 2004-2005 period and later revisited in 2010-2011. We observed that dissolved organic nitrogen (DON) increased about two- and ten-fold at Port Klang and Port Dickson, respectively and resulted in a significant change in DOC:DON ratio (t 0.05). Among the bacterial processes measured, bacterial respiration (BR) was lower in the 2010-2011 period at both stations (t 0.01). BR also correlated to the DOC:DON ratio (R2 0.259, p < 0.01). The increase in substrate quality enabled the bacteria to respire less in the dissolved organic matter degradation. As a result, the average bacterial growth efficiency increased slightly in the 2010-2011 period.

Automated summary

The study indicated that in the 2010-2011 period, the dissolved organic nitrogen concentration significantly increased at two tropical coastal sites in Peninsular Malaysia, resulting in a decrease in bacterial respiration rate and a slight improvement in bacterial growth efficiency.