ASLO Summer Meeting 2005, Santiago de Compostela

1. Application of the ASSETS eutrophication assessment methodology to four contrasting Chinese coastal systems Sanggou Bay Huangdun Bay ASLO Summer Meeting 2005, Santiago de Compostela Session SS72: Assessing and Modelling Eutrophication June 22nd 2005 http://www.eutro.org S.B. Bricker, R. Callender, G.C. Matlock NOAA J.G. Ferreira, A.M. Nobre IMAR X.L.Zhang, M.Y. Zhu, B. Wang First Institute of Oceanography X. Yan Ningbo University

2. China – General study area ASSETS was applied to four very different coastal systems in China • Span 8 degrees of latitude (~900km); • Include estuaries and coastal bays; • Vary in size and human use; • From sparsely populated to heavily populated;

3. Bohai Sea Yellow Sea East China Sea Location of the four systems Area Volume Depth Type Catchment population (km2) (106 m3) (m) (X 106) 140 1000 7.5 Coastal 0.200 bay 390 1900 7 Coastal 4.9 bay 51000 637500 8 Estuary 400 90 1125 8 Estuary ? Sanggou Wan Jiaozhou Wan Changjiang estuary Huangdun Wan

4. Sanggou Bay, showing aquaculture areas

5. Jiaozhou Bay Land Intertidal 0 m 40 m

6. Changjiang Estuary

7. 3 梅山 1 4 6 山 8 象 11 10 强蛟码头 2 5 钱仓 西沪港口 9 12 注 水文站 潮位站 Huangdun Bay 六 横 岛 港 7

8. Symptoms and Consequences of Nutrient Enrichment Nutrient Inputs Primary Secondary Consequences and Processing Impacts Impacts of Symptoms High algal production Loss of water clarity Epiphyte problems Macroalgal problems Fish kills Loss of habitat Human health risks Loss of tourism Closed fishing grounds Increased N and P concentration Loss of SAV Low D.O Nuisance/Toxic blooms The Problem – The Assessment Approach ASSETS: Pressure - State - Response P: Overall Human Influence (OHI) – Natural processing + Human Nutrient Load S: Overall Eutrophic Condition (OEC) – Condition of waterbody R: Determination of Future Outlook (DFO) – What will happen in the future? http://www.eutro.org

9. ASSETS: HIGH Sanggou Bay – ASSETS Application Index LOW LOW NO CHANGE Parameters Rating Level of expression Dilution potential HIgh Low susceptibility Flushing potential Moderate Moderate Chlorophyll a Low Low Macroalgae No Problem Dissolved Oxygen No Problem Submerged Aquatic No Problem Vegetation Low Nuisance and Toxic No Problem Blooms Future nutrient pressures remain the same Indices Overall Human Influence (OHI) ASSETS: 5 Overall Eutrophic Condition (OEC) ASSETS: 5 Determination of Future Outlook (DFO) ASSETS: 3 Methods Susceptibility Nutrient inputs Primary Secondary Future nutrient pressures Estuary Characteristics: Main issues and impacts: Population (X 103) 200 Nutrient loading (tN y-1) 800 Mean depth (m) 7.5 Mean tidal range (m) 1.5 Water residence time (d) 20 Cultivation of scallops, oysters, kelp – high summer bivalve mortality from disease

10. ASSETS: HIGH Jiaozhou Bay – ASSETS Application Index MODERATE LOW Improve Low Parameters Rating Level of expression Dilution potential Moderate Moderate susceptibility Flushing potential Moderate Moderate Low Chlorophyll a Low Low Macroalgae No Problem Dissolved Oxygen Low Submerged Aquatic Low Vegetation Low Nuisance and Toxic Low Blooms Future nutrient pressures decrease Indices Overall Human Influence (OHI) ASSETS: 3 Overall Eutrophic Condition (OEC) ASSETS: 5 Determination of Future Outlook (DFO) ASSETS: 4 Methods Susceptibility Nutrient inputs Primary Secondary Future nutrient pressures Estuary Characteristics: Main issues and impacts: Population (X 103) 4940 Nutrient loading (tN y-1) 13997 Mean depth (m) 7 Mean tidal range (m) 2.4 Water residence time (d) 52 Cultivation of clams, oysters and scallops, Redfield ratio changed from 10 to 24 in 40 years

11. ASSETS: BAD Changjiang Estuary – ASSETS Application Index HIGH HIGH WORSENHIGH Parameters Rating Level of expression Dilution potential Moderate Moderate susceptibility Flushing potential Moderate High Chlorophyll a Moderate Moderate Macroalgae Unknown Dissolved Oxygen Low Submerged Aquatic Unknonwn Vegetation High Nuisance and Toxic High Blooms Future nutrient pressures increase Indices Overall Human Influence (OHI) ASSETS: 1 Overall Eutrophic Condition (OEC) ASSETS: 1 Determination of Future Outlook (DFO) ASSETS: 1 Methods Susceptibility Nutrient inputs Primary Secondary Future nutrient pressures Estuary Characteristics: Main issues and impacts: Population (X 103) 400,000 Nutrient loading (tN y-1) 1.6 x 106 Mean depth (m) 8 Mean tidal range (m) 2.7 Water residence time (d) ?? 400 million people, HABs increased 10X between 1990-2004, Three Gorges Dam to reduce / economic growth to increase load

12. ASSETS: ?? Huangdun Bay – NEEA/ASSETS Application Index HIGH MODERATE ?? Parameters Rating Level of expression Dilution potential Moderate Moderate susceptibility Flushing potential Moderate High Chlorophyll a High Moderate Macroalgae No Problem Dissolved Oxygen No Problem Submerged Aquatic Unknonwn Vegetation Moderate Nuisance and Toxic Moderate Blooms ??? Indices Overall Human Influence (OHI) ASSETS: 1 Overall Eutrophic Condition (OEC) ASSETS: 3 Determination of Future Outlook (DFO) ASSETS: ?? Methods Susceptibility Nutrient inputs Primary Secondary Future nutrient pressures Estuary Characteristics: Main issues and impacts: Population (X 103) ?? Nutrient loading (tN y-1) 463 Mean depth (m) 8 Mean tidal range (m) 0.39 Water residence time (d) ?? Outer channel influenced by the Changjiang plume, aquaculture of finfish, oysters, Enteromorpha, and Porphyra

13. ASSETS: 4 Chinese Systems Sanggou Jiaozhou Changjiang Huangdun ASSETS: HIGH ASSETS: HIGH ASSETS: BAD ASSETS: ?? Indices Overall Human Influence (OHI) Overall Eutrophic Condition (OEC) Determination of Future Outlook (DFO) MODERATE LOW LOW IMPROVE LOW LOW LOW NO CHANGE HIGH HIGH WORSENHIGH HIGH MODERATE ?? Population (X 103) 200 4,940 400,000 ?? Loading (tN y-1) 800 13,997 1,600,000 463 Watershed Rural Urban Heavily populated Rural characteristics Other influences Aquaculture Aquaculture, sewage, Sewage, industry, Aquaculture shipping, recreation shipping Management: GEF/UNEP Yellow Sea Large Marine Ecosystem (www.yslme.org), China Blue Sea Action Plan, Total Load Control Plan (in development), particularly hotspots (ie Changjiang)

14. Concluding Remarks • ASSETS has been successfully applied to four Chinese systems • The Changjiang (Yangtze) is the most impacted and also the most populated watershed. Management plans include the GEF/UNEP Yellow Sea Large Marine Ecosystem, China Blue Sea Action Plan, and the Total Load Control Plan which addresses hotspots • Despite multiple uses, Jiaozhou Bay has a low impact and is expected to improve from sewage treatment implementation /upgrades. Shellfish aquaculture may play a pivotal role in reducing the concentration of particulate organic material; • Opportunistic macroalgae are considered a problem in the US and EU - but in China, algae such as Enteromorpha are cultured for harvest, so the ASSETS criteria must be adapted to local considerations; • HABs are a major problem both in parts of the Yellow Sea and in the East China Sea, and lower the ASSETS scores for some systems. As in other parts of the world, it is unclear what (if any) management measures may be taken to correct this.