| The sustainable development of mariculture plays an important role in promoting the economic development of coastal areas.However,mariculture pollution has become the main source of pollution in offshore environment,and different types of mariculture have different water quality requirements and pollution intensity.How to effectively monitor the mariculture water environment and evaluate the pollution of mariculture,master the spatio-temporal variation of aquaculture water quality parameters,optimize the spatial structure of mariculture,serve and guide the healthy production of fishery.Reducing the pollution effect of mariculture is an urgent problem which needs to be studied urgently.with the expansion of mariculture capacity and the unreasonable cultivation methods,the water pollution of aquaculture is serious and the ecological environment is out of balance.It brings great risk to the development of mariculture.Taking Zhelin Bay in eastern Guangdong Province as the study area,this paper explores the remote sensing monitoring method of marine aquaculture pollution.According to the characteristics of wide range,many types and dynamic characteristics of mariculture,the use of satellite remote sensing technology to carry out mariculture pollution Dyeing monitoring and evaluation is a very effective means of monitoring.The main findings are:(1)Based on the measured water quality parameters concentration and normalization,first-order differential and second-order differential treatment of water reflectivity correlation analysis,it is found that the first-order differential spectral reflectivity and the water quality parameters concentration correlation effect is better than that of the first-order differential spectral reflectivity.(2)The hyperspectral inversion model of water quality parameters is established by using the optimal sensitive band and the ratio method to verify the accuracy of the model.The results showed that the specific value method was better than single band,and the single quadratic function model R~2 was the largest,and the accuracy of chlorophyll a,dissolved oxygen,ammonia nitrogen,total phosphorus and chemical oxygen demand were 0.833,0.796,0.803,0.789,0.813,respectively.(3)Based on the Sentinel 2 satellite data,the temporal and spatial characteristics of water quality parameters were analyzed in Zhelin Bay mariculture area.In 2018,there were significant temporal and spatial differences in chlorophyll a,dissolved oxygen,ammonia nitrogen,total phosphorus and chemical oxygen demand in Zhelin Bay mariculture area in eastern Guangdong.The effects of temperature,rainfall and culture cycle were different of water quality parameters.(4)The water quality of the mariculture area was evaluated by comprehensive nutritional status index method in Zhelin Bay.The state of nutrition changed from"middle nutrition"to"medium eutrophication"to"moderate eutrophication"in the mariculture area of Zhelin Bay,eastern Guangdong Province in 2018.(5)The improved area estimation method was used to evaluate the pollution load and contribution rate of different aquaculture models:The main pollution load of mariculture was 8720.76 t,of which the total nitrogen load was 1381.44 t,The total phosphorus load and chemical oxygen demand load are 137.65 t and 7154.46 t respectively in Zhelin Bay in 2018.The maximum pollution degree of pond culture was 54.17%,followed by pond culture 31.15%,and the minimum of high-level pond culture was 0.67%.Therefore,the farmers should adjust the culture density according to the culture cycle,reasonably control the culture scale,optimize the culture production mode and protect the breeding ecological environment. |
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