基于GIS的福田红树林水环境健康评价

GIS-based water environmental health assessments of Futian mangrove reserve

红树林水环境质量对红树林生态系统的健康有重要影响。本研究测定了福田红树林保护区2014年4月至2015年1月的水体水质,并基于GIS(Geographic Information System)平台的应用空间插值法对其进行空间可视化表征,综合分析了红树林区水环境的健康状况。结果表明:水体溶解氧(DO)为0.88~5.52 mg·L^(–1),且在核心区(春夏季节)、缓冲区(秋季)以及实验区(冬季)存在点状分布的低氧区;氧化还原电位(ORP)为-205.59~162.00 mV,低于天然海水的氧化还原电位值(0.74 V);水体的pH、浊度及盐度分别为6.5~7.8、20.71~57.66 NTU和3.71~22.89‰。水体总氮(TN,0.42~3.78 mg·L^(–1))和总磷(TP,0.32~1.79 mg·L^(–1))分别为劣IV类和劣Ⅴ类;二者在缓冲区和核心区水域总体为高值。水体的COD(25.13~71.76 mg·L^(–1))和BOD(7.01~20.07 mg·L^(–1))在实验区的基围鱼塘水域分别劣于地表水Ⅲ类和Ⅳ类。红树林区水体中浮游动物多样性指数为3.26~4.30,且在春秋季节达到较高水平。研究结果表明福田红树林水体环境存在一定的生态风险,亟需加强对水体富营养化的防治。

The quality of mangrove water environment has an important impact on the health of mangrove ecosystems.In this study,a Geographic Information System based spatial interpolation method was applied to spatially visualize the water quality indicators of Futian mangrove reserve from Apr.2014 to Jan.2015.Furthermore,the health status of the water environment was comprehensively analyzed.The results showed that the dissolved oxygen(DO)content in water ranged from 0.88 to 5.52 mg·L^(–1),and there were dotted low-oxygen areas in the core area in spring and summer,buffer area in autumn and test area in winter.The oxidation-reduction potential(ORP)varied between-205.59 and 162.00 mV,which was lower than the redox potential of natural seawater(0.74 V).The pH,turbidity and salinity of the water varied between 6.5 and 7.8,20.71 and 57.66 NTU,3.71 and 22.89‰,respectively.The seasonal and spatial distribution characteristics of nutrients in water were as follows:the value of total nitrogen(TN,0.42~3.78 mg·L^(–1))and total phosphorus(TP,0.32~1.79 mg·L^(–1))were inferior class IV and V,respectively;both were generally high in the buffer and core areas in the waters.In Geiwei fish pond of test area,the water COD(25.13~71.76 mg·L^(–1))and BOD(7.01~20.07 mg·L^(–1))were inferior to surface waters quality of class III and class IV,respectively.The zooplankton diversity index(H′)in the mangrove area ranged from 3.26 to 4.30,which reached a higher level in spring and autumn.In conclusions,there is a certain ecological risk in the water environment of Futian mangrove forest,and some works need to be carried out to strengthen the prevention and control of water eutrophication.