Restoration of the Marine Ecological Environment Along the Charting Coastal Area: Chemical Studies

Abstract

The Charting coastal area is an important mariculture and fishery ground in Taiwan. Due to copper and organic pollution, mariculture has been prohibited by the Taiwan Government since the first case of green oysters appeared in this area in 1986. Growing algae in the polluted environment may improve water quality and re-establish the marine ecosystem. Since September, 1993, various algal species (such as Ulva, Sargassum, Grateloupia, Halymenia, Galaxura, etc.) have been cultured in the Charting coastal area. Although some of the cultivated algae were damaged by a typhoon in August, 1944, the environmental and ecological effect of the cultivated algae is still evident. the non-biological and biological components surveyed include: salinity, temperature, dissolved oxygen, biochemical oxygen demand (BOD), particulate organic carbon (POC), nutrients, heavy metals and chlorophyll-a, adenosine triphosphate, primary productivity, species composition and intra-specific relationships of phyto- and zoo-plankton. the purpose of this paper is to evaluate the possible impact before and during culture of large algae on the heavy metals and organic pollution of water and sediments over the period August 1992 to May 1995. the results indicate that during algal culture, higher levels of dissolved oxygen (6.1–7.6 mg 1 ⁻¹) with lower BOD (0.4–2.3 mg 1⁻¹) and POC (20.6–948 μg 1⁻¹) were found. the concentrations of copper (0.02–4.7 μg 1⁻¹), zinc (0.90–12.3 μg 1⁻¹), lead (> 0.05–1.47 μg 1⁻¹) and cadmium (> 0.02–0.14 μg 1⁻¹) also decreased. As a result of these positive findings, the cultivation area of algae was expanded in 1995. We expect that with extended algal cultivation, inorganic and organic pollutants will be minimized, and that the marine ecosystem and oyster mariculture will be restored.

Key Words:

• Heavy metals
• organic pollutants
• mariculture
• oysters
• water quality
• marine ecosystem recovery
• Charting sea