In an article entitled, “Coastal Eutrophication as a Driver of Salt Marsh Loss” published in the 17th October issue of Nature, Linda A. Deegan and six coworkers each from a USA-based university have come to the conclusion from a nine-year whole-ecosystem study that nutrient enrichment (particularly of phosphates and nitrates through fertilizers and sewage) gradually leads to loss of salt marsh. Their results which cannot be demonstrated on a small scale study of a shorter duration show that coastal eutrophication have reduced over the years biomass of bank-stabilizing roots below the ground with consequential microbial decomposition of organic matter. Earlier studies have shown that changes in these key ecosystem properties reduce geomorphic stability bringing about consequential creek-bank collapse leading to conversion of creek-bank marsh to extensive areas of mud denuded of any vegetation. This has been shown to be the cause of marsh loss all over the globe creating extensive mudflats and wider creeks. Furthermore, their investigation suggests that current nutrient loading rates to many coastal ecosystems have overwhelmed the capacity of marshes to remove nitrogen without deleterious effects.
Increased eutrophication in metropolitan cities such as Dhaka, Chittagong, Khulna should be a great concern to Bangladesh as it means gradual loss of coastal mangrove vegetation causing ecological imbalance and a health hazard to the population concomitant with its adverse effect on the economy of the country.