胶州湾与大亚湾不同类型湿地对无机氮、磷的净化评估

为分析不同类型湿地对无机氮、磷（DIN和DIP）的净化能力，本文以胶州湾与大亚湾两个典型海湾为例，利用海水-地下水交互速率定量计算海湾湿地的净化能力。结果表明:胶州湾存有沙滩、泥滩、河口潮间带和潮沼4种典型湿地类型，不同类型湿地对DIN的净化能力排序为泥滩＞沙滩＞河口潮间带＞潮沼，对DIP的净化能力排序为沙滩＞泥滩＞河口潮间带＞潮沼，对DIN和DIP的净化能力分别为2.11×105～4.23×105 mol/d和4.29×102～8.22×102 mol/d，估算出由于填海造陆等人类活动导致脱氮量减少3.1～5.4 t/d。大亚湾主要有红树林泥滩、沙滩和泥沙滩3种湿地类型，不同类型湿地对DIN的净化能力排序为红树林泥滩＞沙滩＞泥沙滩，对DIN的净化能力为4.22×107 mol/d，并估算出由于大亚湾红树林泥滩和沙滩湿地面积的减少导致其脱氮量分别减少了1.33×102 t/d和0.81 t/d。

Purification evaluation of DIN and DIP in different types of wetlands in Jiaozhou bay and Daya bay

In order to evaluate the purification capacities of DIN and DIP in different types of wetlands in two typical semi-closed bays (Jiaozhou bay and Daya bay) in China, a quantitative method of seawater-groundwater exchange was used to calculate the purification capacities. Results showed that: there are four wetland types in Jiaozhou bay, including sandy beaches, mud flats, estuarine intertidal zones and tidal marshes, and their purification capacities on DIN sort as follows: mud flats>sandy beaches>estuarine intertidal zones> tidal marshes and DIP sort as follows: sandy beaches>mud flats>estuarine intertidal zones> tidal marshes. The purification rate ranged from 2.11×105 mol/d to 4.23×105 mol/d for DIN and from 4.29×102 mol/d to 8.22×102 mol/d for DIP, respectively. The estimated nitrogen removal rate due to human activities such as land reclamation decreased by 3.1～5.4 t/d. In contrast, there are three wetland types such as mangrove swamps, sandy beaches and silt-sandy beaches in Daya bay. The DIN purification capacities in different types of wetlands in Daya bay sort as follows: mangrove swamps>sandy beaches>silt-sandy beaches, with an average of 4.22×107 mol/d. Due to the area decrease of mangrove swamps and sandy wetlands in Daya bay, the decreased nitrogen removal rate was estimated to be 1.33×102 t/d and 0.81 t/d, respectively.