Characterizing bioavailable phosphorus concentrations in an agricultural stream during hydrologic and streambed disturbances.
Characterizing bioavailable phosphorus concentrations in an agricultural stream during hydrologic and streambed disturbances.
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DOI：
10.1007/s10533-021-00803-w
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发表时间：
2021
期刊：
影响因子：
4
通讯作者：
Goodson HV
中科院分区：
文献类型：
--
作者：
Trentman MT;Tank JL;Shepherd HAM;Marrs AJ;Welsh JR;Goodson HV
在淡水生态系统中，磷通常被认为是一种限制生长的营养物质。农田中化肥的使用导致溪流中磷有效性的径流驱动增加，以及随后下游生态系统的富营养化。孤立的风暴和周期性的河床疏浚是两种常见干扰的例子，它们对农业溪流造成溶解和颗粒磷，可使用过滤水样的钼蓝方法将其量化为可溶性反应磷(SRP)，或通过对反映所有形式的P的未过滤水的消化来测量总P(TP)。目前用于估计BAP的方法没有考虑到生物学的作用(例如，NaOH提取)，或者需要专门的平台(例如，藻类生物测定)。在这里，除了对SRP和TP的常规分析外，我们还使用了一种新的基于酵母的生物测定方法，使用未过滤的样本水来估计两场风暴(顶部80%和 >； 95%的流量分位数)以及下游河段(与管理相关的疏浚活动扰乱了河床)中的生物碱土浓度。我们发现，BAP浓度往往大于SRP，表明SRP不能完全代表P的生物有效性。SRP浓度在两次风暴期间同样升高，但在河床扰动期间一直保持在较低水平。相反，浊度和TP在所有事件中都升高。在所有扰动事件中，BAP浓度与浊度显著相关，但仅在风暴期间与TP相关。新的酵母菌测试表明，BAP的出口可能超过SRP，特别是当溪流不平衡时，如风暴上升的边缘或在积极疏浚期间。
In freshwater ecosystems, phosphorus (P) is often considered a growth-limiting nutrient. The use of fertilizers on agricultural fields has led to runoff-driven increases in P availability in streams, and the subsequent eutrophication of downstream ecosystems. Isolated storms and periodic streambed dredging are examples of two common disturbances that contribute dissolved and particulate P to agricultural streams, which can be quantified as soluble reactive P (SRP) using the molybdate-blue method on filtered water samples, or total P (TP) measured using digestions on unfiltered water reflecting all forms of P. While SRP is often considered an approximation of bioavailable P (BAP), research has shown that this is not always the case. Current methods used to estimate BAP do not account for the role of biology (e.g., NaOH extractions) or require specialized platforms (e.g., algal bioassays). Here, in addition to routine analysis of SRP and TP, we used a novel yeast-based bioassay with unfiltered sample water to estimate BAP concentrations during two storms (top 80% and > 95% flow quantiles), and downstream of a reach where management-associated dredging disturbed the streambed. We found that the BAP concentrations were often greater than SRP, suggesting that SRP is not fully representative of P bioavailability. The SRP concentrations were similarly elevated during the two storms, but remained consistently low during streambed disturbance. In contrast, turbidity and TP were elevated during all events. The BAP concentrations were significantly related to turbidity during all disturbance events, but with TP only during storms. The novel yeast assay suggests that BAP export can exceed SRP, particularly when streams are not in equilibrium, such as the rising limb of storms or during active dredging.
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影响因子：
64.8
作者：
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通讯作者：
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