Application of the ASSETS eutrophication assessment methodology to four contrasting Chinese coastal systems ASLO Summer Meeting 2005, Santiago de Compostela Session SS72: Assessing and Modelling Eutrophication June 22 nd S.B. Bricker, R. Callender, G.C. MatlockNOAA J.G. Ferreira, A.M. NobreIMAR X.L. Zhang, M.Y. Zhu, B. WangFirst Institute of Oceanography X. YanNingbo University Sanggou BayHuangdun Bay

China – General study area ASSETS was applied to four very different coastal systems in China lSpan 8 degrees of latitude (~900km); lInclude estuaries and coastal bays; lVary in size and human use; lFrom sparsely populated to heavily populated;

Location of the four systems Sanggou Wan Jiaozhou Wan Changjiang estuary Huangdun Wan AreaVolumeDepthTypeCatchment population (km 2 )(10 6 m 3 )(m)(X 10 6 ) Coastal0.200 bay Coastal4.9 bay Estuary Estuary? Bohai Sea Yellow Sea East China Sea

Sanggou Bay, showing aquaculture areas Aquaculture areas: Oysters 391 ha Scallop 3400 ha Kelp 4400 ha

Jiaozhou Bay Land Intertidal 0 m 40 m

Changjiang Estuary

Huangdun Bay 注 水文站 潮位站 钱仓 梅山 西沪港口 象 山 强蛟码头 7 六 横 岛 港

The Problem – The Assessment Approach 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 Loss of SAV Low D.O Nuisance/Toxic blooms Increased N and P concentration Symptoms and Consequences of Nutrient Enrichment Nutrient InputsPrimarySecondaryConsequences and ProcessingImpactsImpactsof Symptoms 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? ASSETS: Pressure - State - Response

Sanggou Bay – ASSETS Application 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 ParametersRatingLevel of expression Dilution potentialHIghLow susceptibility Flushing potentialModerate Moderate Chlorophyll aLow Low MacroalgaeNo Problem Dissolved Oxygen No Problem Submerged Aquatic No Problem Vegetation Low Nuisance and Toxic No Problem Blooms Future nutrient pressures remain the same Index LOW NO CHANGE ASSETS: HIGH Cultivation of scallops, oysters, kelp – high summer bivalve mortality from disease Population (X 10 3 ) 200 Nutrient loading (tN y -1 ) 800 Mean depth (m) 7.5 Mean tidal range (m) 1.5 Water residence time (d) 20 Estuary Characteristics:Main issues and impacts:

Jiaozhou Bay – ASSETS Application 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 ParametersRatingLevel of expression Dilution potentialModerateModerate susceptibility Flushing potentialModerate Moderate Low Chlorophyll aLow Low MacroalgaeNo Problem Dissolved Oxygen Low Submerged Aquatic Low Vegetation Low Nuisance and Toxic Low Blooms Future nutrient pressures decrease Index MODERATE LOW Improve Low ASSETS: HIGH Cultivation of clams, oysters and scallops, Redfield ratio changed from 10 to 24 in 40 years Population (X 10 3 ) 4940 Nutrient loading (tN y -1 ) Mean depth (m) 7 Mean tidal range (m) 2.4 Water residence time (d) 52 Estuary Characteristics:Main issues and impacts:

Changjiang Estuary – ASSETS Application 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 ParametersRatingLevel of expression Dilution potentialModerateModerate susceptibility Flushing potentialModerate High Chlorophyll aModerate Moderate MacroalgaeUnknown Dissolved Oxygen Low Submerged Aquatic Unknonwn Vegetation High Nuisance and Toxic High Blooms Future nutrient pressures increase Index HIGH WORSEN HIGH ASSETS: BAD 400 million people, HABs increased 10X between , Three Gorges Dam to reduce / economic growth to increase load Population (X 10 3 ) 400,000 Nutrient loading (tN y -1 ) 1.6 x 10 6 Mean depth (m) 8 Mean tidal range (m) 2.7 Water residence time (d) ?? Estuary Characteristics:Main issues and impacts:

Huangdun Bay – NEEA/ASSETS Application 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 ParametersRatingLevel of expression Dilution potentialModerateModerate susceptibility Flushing potentialModerate High Chlorophyll aHigh Moderate Macroalgae No Problem Dissolved Oxygen No Problem Submerged Aquatic Unknonwn Vegetation Moderate Nuisance and Toxic Moderate Blooms ??? Index HIGH MODERATE ?? ASSETS: ?? Outer channel influenced by the Changjiang plume, aquaculture of finfish, oysters, Enteromorpha, and Porphyra Population (X 10 3 ) ?? Nutrient loading (tN y -1 ) 463 Mean depth (m) 8 Mean tidal range (m) 0.39 Water residence time (d) ?? Estuary Characteristics:Main issues and impacts:

ASSETS: 4 Chinese Systems Indices Overall Human Influence (OHI) Overall Eutrophic Condition (OEC) Determination of Future Outlook (DFO) Population (X 10 3 )2004,940400,000?? Loading (tN y -1 )80013,9971,600, Watershed RuralUrbanHeavily populatedRural characteristics Other influencesAquacultureAquaculture, sewage,Sewage, industry,Aquaculture shipping, recreationshipping Management: GEF/UNEP Yellow Sea Large Marine Ecosystem ( China Blue Sea Action Plan, Total Load Control Plan (in development), particularly hotspots (ie Changjiang) Sanggou HuangdunJiaozhouChangjiang HIGH MODERATE ?? ASSETS: ?? HIGH WORSEN HIGH ASSETS: BAD MODERATE LOW IMPROVE LOW ASSETS: HIGH LOW NO CHANGE ASSETS: HIGH

Concluding Remarks l ASSETS has been successfully applied to four Chinese systems lThe 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 l 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; l 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; l 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.