Giesbrecht Ian J W, Lertzman Ken P, Tank Suzanne E, Frazer G W, St Pierre Kyra A, Gonzalez Arriola Santiago, Desmarais Isabelle, Haughton Emily
Hakai Institute and Simon Fraser University, Vancouver, British Columbia Canada.
Simon Fraser University and Hakai Institute, Vancouver, British Columbia Canada.
Ecosystems. 2025;28(2):25. doi: 10.1007/s10021-025-00964-x. Epub 2025 Mar 31.
Small coastal watersheds (< 10,000 km) can play a large role in forming biogeochemical linkages between land and sea, yet the spatial heterogeneity of small watershed ecosystems is poorly understood due to sparse observations in many regions. In this study, we examined the spatial heterogeneity of water quality exported from diverse watersheds in two rainforest fjordland complexes. Samples were collected about monthly for a year from the outlets of 56 watersheds spanning from high mountains to low islands. Many (20) water quality properties varied significantly across six previously established watershed types defined by 12 easily computed geospatial variables. For example, organic matter concentrations ranged from very low in a Glacierized Mountains watershed type (1.2 ± 0.1 mg L DOC; 28.5 ± 4.6 µg L DON) to very high (15.1 ± 1.0 mg L DOC; 215.6 ± 20.4 µg L DON) in a Rain Lowlands type. Along this gradient, the dominant form of dissolved nitrogen switched from inorganic to organic and the dominant form of phosphorous switched from particulate to dissolved. Watershed type alone explained 67% of the variance in the first principal component of water quality (PC1) representing 20 water properties. Although underlying causes were likely complex, a great deal of spatial variation in water quality (for example, 91% of PC1) was predicted by simple measures of topography and climate (for example, elevation and mean annual precipitation). The physiographic structure of the coastal land mass appears to enable a complex mosaic of watershed ecosystems, which may affect meta-ecosystem function at the coastal margin.
The online version contains supplementary material available at 10.1007/s10021-025-00964-x.
小型沿海流域（<10000平方公里）在陆地与海洋之间形成生物地球化学联系方面可发挥重要作用，但由于许多地区观测数据稀少，小型流域生态系统的空间异质性仍知之甚少。在本研究中，我们考察了两个雨林峡湾地区不同流域输出水质的空间异质性。在一年时间里，大约每月从56个流域的河口采集样本，这些流域范围从高山到低岛。许多（20种）水质属性在由12个易于计算的地理空间变量定义的六种先前确定的流域类型中差异显著。例如，在冰川山脉流域类型中，有机质浓度非常低（溶解有机碳1.2±0.1毫克/升；溶解有机氮28.5±4.6微克/升），而在雨林低地类型中则非常高（溶解有机碳15.1±1.0毫克/升；溶解有机氮215.6±20.4微克/升）。沿着这个梯度，溶解态氮的主要形式从无机态转变为有机态，磷的主要形式从颗粒态转变为溶解态。仅流域类型就解释了代表20种水质属性的水质第一主成分（PC1）中67%的方差。尽管潜在原因可能很复杂，但通过地形和气候的简单测量（例如海拔和年平均降水量）可以预测大量水质的空间变化（例如，PC1的91%）。沿海陆地的地貌结构似乎形成了一个复杂的流域生态系统镶嵌体，这可能会影响沿海边缘的元生态系统功能。
在线版本包含可在10.1007/s10021-025-00964-x获取的补充材料。
