Impact of brackish water aquaculture and mangrove degradation on global carbon balance

Abstract

One of the most productive and supportive ecosystems, the mangroves, have faced a sharp decline of 1.04 million hectares globally, mostly due to population pressure and environmental changes related to the recent effects of global warming and climate change. The loss of area, species migration, altered ecological services etc. are among the most discussed concerns, as evident from the volumes of literatures. However, these issues have overshadowed the fact that along with biodiversity, globally we are losing an important and efficient carbon sink - the mangrove lands. The lost mangrove patches and their conversion to aquaculture, agriculture, or simply settlement areas significantly alter the carbon budget. Sometimes conversion of mangroves to agriculture or aquaculture farms even reverses the roles and the sink has been reported to have become a source of carbon - alternatively known as blue carbon emission. This article provides an overview of the impacts of coastal aquacultures, particularly established in expense of mangrove lands and its consequence on global carbon budget. It has been observed that this globally predominant land use change practices not only significantly reduce the carbon sink capacity but also frequently act as indirect source of the same.