Massive sedimentation of fine sediment with organic matter and enhanced benthic–pelagic coupling by an artificial dyke in semi-enclosed Chonsu Bay, Korea

Lee, Jae-seong; Kim, Kee Hyun; Shim, JungHee; Han, Jeong Hee; Choi, Yang Ho; Khang, Bhum-Joo

Massive sedimentation of fine sediment with organic matter and enhanced benthic–pelagic coupling by an artificial dyke in semi-enclosed Chonsu Bay, Korea

2012

To assess the impact of an artificial dyke in Chonsu Bay (CBD) on the organic carbon (Cₒᵣg) cycle, we measured excess ²¹⁰Pb activities, Cₒᵣg and nitrogen content in sediment cores. The Cₒᵣg oxidation rates (Cₒₓ) on the surface sediment and benthic nutrient fluxes were also quantified with an in situ benthic chamber. The higher excess ²¹⁰Pb inventory, Cₒᵣg and nitrogen in cores near the CBD indicated lateral transport and local, massive deposition of particulate matter due to tidal circulation altered by artificial dyke construction. The Cₒₓ in sediment near the CBD was about twice as high as that out of the bay, suggesting the importance of benthic remineralization of organic matter. The benthic fluxes of dissolved inorganic nitrogen and phosphate were four to six times higher than those outside the bay, corresponding to 141% and 131% respectively, of the requirements for primary production.

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