Sun Long, Tang Jianfeng, Zhao Hongtao, Yang Lei, Sun Ranhao, Chen Liding
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 China; University of Chinese Academy of Sciences, Beijing 100049 China.
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315800, China.
Water Res. 2025 Jan 1;268(Pt A):122605. doi: 10.1016/j.watres.2024.122605. Epub 2024 Oct 9.
Landscape patterns and water age are considered to play similar roles in influencing water quality, as human-caused landscape fragmentation usually leads to complex hydrological pathways and older water ages. The young streamflow fraction (F), which can significantly alter water age, is believed to disproportionately impact water quality. Landscape and F thus may play different roles in streamwater quality, but this assumption has not been examined. Here we examined the roles of F (estimated by the amplitudes of seasonal cycles of oxygen isotope ratios in precipitation (A) and streamwater (A)) and landscape pattern (reflected by common landscape metrics) in streamwater quality over 7 forest-dominated catchments in eastern China. Landscape metrics, indicating land use arrangement, were closely related to multiple water quality parameters, suggesting a close association between stream water quality (sinks) and land use (sources). The F had a positive relationship with ammonia nitrogen (R = 0.51, P = 0.044) and a negative relationship with nitrate nitrogen (R = 0.62, P = 0.022). The F, determined by the heterogeneous-independent A/A, offers the possibility of modeling nitrogen compounds across multiple spatial scales. Importantly, the water quality parameters that significantly correlated with F did not correlate with the landscape metrics. Differences in correlations of landscape and F to water quality parameters imply that landscape and F differed in their roles in water quality parameters, as well as the consideration for different water quality management strategies for different contaminants.
景观格局和水龄被认为在影响水质方面发挥着相似的作用，因为人为造成的景观破碎化通常会导致复杂的水文路径和更长的水龄。能够显著改变水龄的年轻径流比例（F），被认为对水质有不成比例的影响。因此，景观和F在河流水质中可能发挥不同的作用，但这一假设尚未得到检验。在这里，我们研究了F（通过降水（A）和河流水（A）中氧同位素比率的季节循环幅度估算）和景观格局（由常见景观指标反映）在中国东部7个以森林为主的集水区河流水质中的作用。表明土地利用布局的景观指标与多个水质参数密切相关，这表明河流水质（汇）与土地利用（源）之间存在密切关联。F与氨氮呈正相关（R = 0.51，P = 0.044），与硝态氮呈负相关（R = 0.62，P = 0.022）。由非均匀独立的A/A确定的F，为跨多个空间尺度模拟氮化合物提供了可能性。重要的是，与F显著相关的水质参数与景观指标不相关。景观和F与水质参数相关性的差异意味着景观和F在水质参数中的作用不同，以及针对不同污染物的不同水质管理策略的考量也不同。
