Phosphorus (P) pollution of surface waters remains a challenge for protecting and improving water quality. Central to the challenge is understanding what regulates P concentrations in streams. This quantitative review synthesizes the literature on a major control of P concentrations in streams at baseflow - the sediment P buffer - to better understand streamwater-sediment P interactions. We conducted a global meta-analysis of sediment equilibrium phosphate concentrations at net zero sorption (EPC0 ), which is the dissolved reactive P (DRP) concentration towards which sediments buffer solution DRP. Our analysis of 45 studies and >900 paired observations of DRP and EPC0 showed that sediments often have potential to remove or release P to the streamwater (83% of observations), meaning that 'equilibrium' between sediment and streamwater is rare. This potential for P exchange is moderated by sediment and stream characteristics including: sorption affinity, stream pH, exchangeable P concentration, and particle sizes. The potential for sediments to modify streamwater DRP concentrations is often not realized owing to other factors, e.g., hydrologic interactions. Sediment surface chemistry, hyporheic exchange, and biota can also influence the potential exchange of P between sediments and the streamwater. Methodological choices significantly influenced EPC0 determination and thus the estimated potential for P exchange: we therefore discuss how to measure and report EPC0 to best suit research objectives and aid in inter-study comparison. Our results enhance understanding of the sediment P buffer and inform how EPC0 can be effectively applied to improve management of aquatic P pollution and eutrophication. equilibrium phosphate concentration, eutrophication, lotic, river, sorption This article is protected by copyright. All rights reserved.

中文翻译：

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基流河流中沉积物磷的缓冲：荟萃分析

地表水的磷 (P) 污染仍然是保护和改善水质的挑战。挑战的核心是了解是什么调节了溪流中的 P 浓度。这篇定量综述综合了关于基流中河流中磷浓度的主要控制——沉积物磷缓冲——的文献，以更好地理解河流-沉积物磷的相互作用。我们对净零吸附 (EPC0) 下的沉积物平衡磷酸盐浓度进行了全球荟萃分析，这是沉积物缓冲溶液 DRP 的溶解活性磷 (DRP) 浓度。我们对 DRP 和 EPC0 的 45 项研究和超过 900 次配对观测的分析表明，沉积物通常有可能将 P 去除或释放到溪水中（占观测的 83%），这意味着“平衡” 沉积物和溪水之间很少见。这种 P 交换的潜力受沉积物和河流特性的影响，包括：吸附亲和力、河流 pH 值、可交换 P 浓度和颗粒大小。由于其他因素，例如水文相互作用，沉积物改变河流 DRP 浓度的潜力通常没有实现。沉积物表面化学、下流交换和生物群也可以影响沉积物和河流水之间的潜在磷交换。方法选择显着影响了 EPC0 的确定，从而影响了 P 交换的估计潜力：因此，我们讨论了如何测量和报告 EPC0 以最适合研究目标并帮助研究间比较。我们的结果增强了对沉积物 P 缓冲液的理解，并告知如何有效地应用 EPC0 来改善水生 P 污染和富营养化的管理。平衡磷酸盐浓度、富营养化、乳液、河流、吸​​附 本文受版权保护。版权所有。