马来西亚东部典型泥炭地河流和河口溶解态锰的地球化学特征与影响因素

Distributions, Seasonal Variations and Influencing Factors of Dissolved Manganesein the Peatland-Draining Rivers and Estuaries of Sarawak, East Malaysia

本文利用催化动力学分光光度法测定了2016年8月(旱季)马来西亚东部泥炭地河流拉让(Rajang)河及河口溶解态锰(DMn)的浓度和2017年3月(雨季)Rajang、马鲁丹(Maludam)、实文然(Simunjan)、实巫友(Sebuyau)、Samunsam和土马丹(Sematan)河及河口DMn的浓度。Rajang河流域旱、雨季DMn浓度分别为(300.3±305.3) nmol·L^(-1)、(424.3±290.3) nmol·L^(-1),无显著性差异(t-检验,P>0.05)。雨季Rajang河DMn浓度与Maludam、Simunjan、Sebuyau、Samunsam和Sematan河之间无显著性差异,说明马来西亚东部砂拉越(Sarawak)州泥炭地河流DMn空间差异不显著。河口DMn在旱、雨季表现出不同的混合行为,旱季Rajang河口DMn表现为非保守混合行为,在盐度0~20区间存在明显的外源输入,而雨季则表现为保守混合行为。Talang岛周围海域DMn浓度为(51.3±3.9) nmol·L^(-1),高于海南岛和越南东部邻近海域DMn浓度。水团的物理混合、悬浮颗粒物的吸附解吸是影响马来西亚Ssrawak州六条泥炭地河流及河口DMn的主要因素。由于马来西亚泥炭地有机物浓度较高,泥炭地河流中的DMn浓度高于其他气候带河流。Rajang河输送至南海的DMn通量为3.3×10^(6) kg·a^(-1),泥炭地河流对南海DMn浓度具有重要影响。

The concentrations of dissolved manganese(DMn)in eastern Malaysia peatland rivers,including Rajang River and its estuary in August,2016(the dry season),and Rajang,Maludam,Simunjan,Sebuyau,Samunsam and Sematan rivers and their estuaries in March,2017(the wet season),were determined using the catalytic kinetic spectrophotometry method.The DMn concentrations in the dry and wet seasons in the Rajang River water were(300.3±305.3)nmol·L^(-1) and(424.3±290.3)nmol·L^(-1),respectively,with insignificant difference(t-test,P>0.05).During the wet season,there was no significantly difference among the Rajang and Maludam,Simunjan,Sebuyau,Samunsam and Sematan Rivers,indicating that there was no significantly spatial difference.The behavior of DMn in the Rajang estuaries were different in two seasons.It showed a non-conservative mixing behavior of DMn in the dry season with significant external addition in the salinity range of 0~20,while a conservative mixing behavior was found in the wet season.The DMn concentration in the coastal water around Talang Island was(51.3±3.9)nmol·L^(-1),which was significantly higher than that in the coastal water around Hainan Island and eastern Vietnam.Water masses mixing,the adsorption and desorption of the suspended particulate matter are assumed to be important factors on the behavior of DMn in the six peatland-draining rivers and estuaries of Sarawak,Malaysia.Due to the high concentration of organic matter in Malaysian peatlands,DMn concentrations in peatland-draining rivers are higher than in other climate zones.The DMn flux from the Rajang River to the South China Sea was 3.3×10^(6) kg·a^(-1),and the peatland-draining rivers had a pivotal influence on the DMn concentration in the South China Sea.