Assessing the changes in river water quality across a land-use change (forest to oil palm plantation) in peninsular Malaysia using the stable isotopes of water and nitrate
Assessing the changes in river water quality across a land-use change (forest to oil palm plantation) in peninsular Malaysia using the stable isotopes of water and nitrate
复制标题
使用水和硝酸盐的稳定同位素评估马来西亚半岛土地利用变化（森林到油棕种植园）的河流水质变化
DOI：
10.1016/j.scitotenv.2022.160319
复制
发表时间：
2023
影响因子：
9.8
通讯作者：
Satomi Shiodera
中科院分区：
文献类型：
--
作者：
Masayuki Itoh;Ken'ichi Osaka;Kotaro Iizuka;Yoshiko Kosugi ;Marryanna Lion;Satomi Shiodera
土地从天然林转变为种植园（例如，在东南亚的热带雨林（油棕榈）是全世界发生的最密集的土地利用变化之一。为了阐明油棕种植园对水质的影响，我们在马来西亚半岛的雨季结束时进行了为期3年（2013-2015）的多点河流和溪流水采样。我们测量了马来西亚半岛两条主要河流的上游山区森林水体和中游水体中主要溶解离子和水（δ 2 H-H2O和δ 18 O-H2O）和硝酸盐（δ 15 N-NO3-和δ 18 O-NO3-）的稳定同位素比值。电导率增加，和d-过量值（作为蒸发程度的指标）随着距离的增加而减小，这表明蒸发富集和污染物的添加效果。通过对水质数据的聚类分析，将采样点分为四组（G1-G4）。从卫星图像和当地信息开发的土地利用/土地覆盖（LULC）分类图中，我们发现G1和G2主要由森林地区的采样点组成，而G3和G4位于油棕影响区。主要离子的浓度在油棕区较高，表明肥料和石灰石的影响（即，pH调节）应用。溶解无机氮浓度在各组之间没有差异，但溶解有机碳、总溶解氮和δ 15 N-NO3 −在油棕区高于森林区。虽然氮浓度很低，但即使在油棕区，油棕区的δ 15 N-NO3 −也明显较高，表明存在大量的反硝化作用。这意味着反硝化作用有助于降低油棕榈地区河流中的NO3−浓度，以及油棕榈树的营养吸收。
Land conversion from natural forests to plantations (e.g., oil palm) in Southeast Asia is one of the most intensive land-use changes occurring worldwide. To clarify the effects of oil palm plantations on water quality, we conducted multipoint river and stream water sampling in peninsular Malaysia at the end of the rainy season over a 3-year period (2013–2015). We measured the major dissolved ions and stable isotope ratios of water (δ2H-H2O and δ18O-H2O) and nitrate (δ15N-NO3−and δ18O-NO3−) in water from the upper streams in mountainous forests to the midstream areas of two major rivers in peninsular Malaysia. The electrical conductivity increased, and thed-excess value (as an index of the degree of evaporation) decreased with increasing distance from the headwaters, suggesting the effect of evaporative enrichment and the addition of pollutants. We separated the sampling points into four groups (G1–G4) through cluster analysis of the water quality data. From the land use/land cover (LULC) classification maps developed from satellite images and local information, we found that G1 and G2 mainly consisted of sampling points in forested areas, while G3 and G4 were located in oil-palm-affected areas. The concentrations of major ions were higher in the oil palm areas, indicating the effects of fertilizer and limestone (i.e., pH adjustment) applications. The dissolved inorganic nitrogen concentration did not differ among the groups, but the dissolved organic carbon, total dissolved nitrogen, and δ15N-NO3−were higher in the oil palm area than in the forested area. Although the nitrogen concentration was low, even in the oil palm area, the significantly higher δ15N-NO3−in the oil palm area indicated substantial denitrification. This implies that denitrification contributed to the lowering of the NO3−concentration in rivers in the oil palm area, in addition to nutrient uptake by oil palm trees.