Watershed and Lake Attributes Dictate Landscape Patterns of Resource Flows in Mountain Lakes
Watershed and Lake Attributes Dictate Landscape Patterns of Resource Flows in Mountain Lakes
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DOI：
10.1029/2020wr027673
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发表时间：
2021-03
影响因子：
5.4
通讯作者：
A. Smits;Bryan Currinder;N. Framsted;L. Loken;D. Lucero;Kelly A Neal;Christine A. Parisek;J. Sic
中科院分区：
文献类型：
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作者：
A. Smits;Bryan Currinder;N. Framsted;L. Loken;D. Lucero;Kelly A Neal;Christine A. Parisek;J. Sic
陆地有机物在多大程度上支持水生消费者仍然不确定，因为对调节资源流动的因素知之甚少。我们采样了12个湖泊，整个内华达州（加州，美国）跨越大梯度的海拔和大小，以评估流域属性和湖泊形态如何影响资源流到湖泊碳库和浮游动物。我们发现，湖泊中碳库的大小和组成往往更强烈地取决于流域或湖泊的功能，而不是海拔位置。使用三种不同的资源来源示踪剂（δ 13 C，Δ 14 C，C：N比），我们发现陆地对大多数湖泊资源库（溶解有机碳，颗粒有机物（POM），沉积物）和浮游动物消费者（浮游动物）的贡献与当地尺度的流域特征（如植被覆盖或流域面积：湖泊面积）而不是海拔高度更密切相关。多种示踪剂的景观格局表明，湖泊内的碳源对不同海拔的大宗资源库（POM，沉积物，浮游动物）的贡献一致。湖泊碳库的δ 13 C富集以及与陆地资源的δ 13 C重叠可能是由于在CO2限制下浮游植物对13 C的分馏减少，因此我们建议在解释δ 13 C的湖泊模式时仔细考虑潜在的环境驱动因素。我们的研究结果强调了地方尺度变化在介导陆地对湖泊食物网的贡献方面的重要性。
The extent to which terrestrial organic matter supports aquatic consumers remains uncertain because factors regulating resource flows are poorly understood. We sampled 12 lakes throughout the Sierra Nevada (California, USA) spanning large gradients in elevation and size to evaluate how watershed attributes and lake morphometry influence resource flows to lake carbon pools and zooplankton. We found that the size and composition of carbon pools in lakes were often more strongly determined by watershed or lake features rather than by elevational position. Using three different tracers of resource origin (δ13C, Δ14C, C:N ratio), we found terrestrial contributions to most lake resource pools (dissolved organic carbon, particulate organic matter (POM), sediments) and pelagic consumers (zooplankton) were more strongly related to local‐scale watershed features such as vegetation cover or watershed area: lake area rather than to elevation. Landscape patterns in multiple tracers indicated consistent contribution of within‐lake C sources to bulk resource pools across elevations (POM, sediments, zooplankton). δ13C‐enrichment of lake C pools and overlap with δ13C of terrestrial resources can arise due to reduced fractionation of 13C by phytoplankton under CO2 limitation, therefore we recommend careful consideration of potential environmental drivers when interpreting among‐lake patterns in δ13C. Our findings emphasize the importance of local‐scale variation in mediating terrestrial contributions to lake food webs.