Ecosystem based approach to delineate coastal degradation of Hawks bay, Karachi, Pakistan

Hawks Bay (HB) a renowned recreational beach, an important small scale fishery and nesting ground of an endangered turtle species encountering massive environmental degradation. Its eastern bay cover scattered mangrove patches and the western bay embraces sandy and rocky beach that terminus the area into great ecological and economic concerns. Here, we have figured out tendency of contamination entering in the ecosystem and elaborate food ∼ web dynamics around HB. An integrated approach was applied to evaluate level of contamination in water, sediments, planktons, seaweeds, mangrove leaves, crabs and fishes. In the sampled population phytoplankton were comprises of (39 Taxa), zooplankton (21), crab (1) and fishes (9) from pelagic demersal domains. The concentration of copper (Cu), iron (Fe), zinc (Zn), lead (Pb) and chromium (Cr) were detected using double-beam Atomic Absorption Spectrophotometer (AAS). The trophic transfer (TTF), contamination factor (CF), pollution load index (PLI), bioaccumulation factor (BAF) and accumulation factor (AF) were calculated round the year. The CF reveals that the area is moderately contaminated whereas PLI (>1) indicate that area is massively polluted by the industrial wastes. Multivariate approach of Principle Component Analysis was applied using pooled data of TTF that defines PC-I (41.56%) and PC- II (31.44%) variability among axes. Evaluation of metal contamination from micro to macro and from surface to bottom exhibits considerable load being received by HB ecosystem echoes stringent actions to curb further degradation of an important area.