Spiraling Down Hillslopes: Nutrient Uptake from Water Tracks in a Warming Arctic
Spiraling Down Hillslopes: Nutrient Uptake from Water Tracks in a Warming Arctic
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螺旋式下降的山坡：变暖的北极从水道中吸收养分
DOI：
10.1007/s10021-019-00355-z
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发表时间：
2019
期刊：
影响因子：
3.7
通讯作者：
S. Godsey
中科院分区：
文献类型：
--
作者：
T. Harms;Christopher L. Cook;A. Wlostowski;M. Gooseff;S. Godsey
水文流路可能会在相连的生态系统之间传播生物地球化学信号，或者由于运输过程中发生的反应或滞留而改变和抑制信号。在北极，实验变暖的陆地苔原释放无机氮（N），但这种新释放的N的命运仍然不清楚。氮可以被动运输下坡流水，或保留时，流路拦截N有限的生态系统。我们应用营养螺旋理论，同时测量铵（NH 4+）和磷酸盐（PO 43 −）的反应和运输，这些营养物质限制了北极生态系统的初级生产力。脉冲施肥实验的重点是被称为水的轨道，水文连接土壤接收河流和湖泊在阿拉斯加高地冻原的流动路径。水迹通常保留PO 43-，但被动运输NH 4+，因此可能将冻土带土壤升温产生的NH 4+传播到下游生态系统。养分吸收不相关的下坡运输的相对比例在瞬态存储区，但更大的NH 4+吸收发生平流水文通量增加相对分散。夏季，随着解冻深度的增加，磷酸盐吸收量下降，这可能是因为深层土壤中生物吸收或吸附能力下降。北极河流生态系统中的磷限制可能会导致无机氮的有效运输到氮有限的透镜和沿海生态系统，在那里增加补贴提供的N损失从变暖的陆地苔原可以支持提高初级生产。
Hydrologic flowpaths might propagate biogeochemical signals among connected ecosystems or alter and dampen signals because of reactions or retention occurring during transport. In the Arctic, experimentally warmed terrestrial tundra releases inorganic nitrogen (N), but the fate of this newly released N remains unclear. Nitrogen could be passively transported downslope in flowing water, or retained when flowpaths intercept N-limited ecosystems. We applied nutrient spiraling theory to simultaneously measure reaction and transport of ammonium (NH4+) and phosphate (PO43−), nutrients limiting primary productivity in Arctic ecosystems. Pulse fertilization experiments were focused on flowpaths known as water tracks that hydrologically connect soils to receiving streams and lakes in upland tundra of Alaska. Water tracks typically retained PO43−, but passively transported NH4+, thus potentially propagating NH4+ produced by warming tundra soils to downstream ecosystems. Nutrient uptake was uncorrelated with the relative proportion of downslope transport in transient storage zones, but greater NH4+ uptake occurred as advective hydrologic flux increased relative to dispersion. Phosphate uptake declined as thaw depth increased over the summer season likely because of declining capacity for biotic uptake or sorption in deeper soils. Phosphorus limitation in fluvial ecosystems of the Arctic might result in efficient transport of inorganic N to N-limited lentic and coastal ecosystems, where increasing subsidies furnished by N loss from warming terrestrial tundra could support enhanced primary production.
影响因子：
3.7
作者：
L. Street;Nora Mielke;S. Woodin
通讯作者：
L. Street;Nora Mielke;S. Woodin