Phosphorus Retention and Remobilization along Hydrological Pathways in Karst Terrain

Abstract

The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. Karst landscapes are often perceived as highly vulnerable to agricultural phosphorus (P) loss, via 14 solution-enlarged conduits that bypass P retention processes. Although attenuation of P 15 concentrations has been widely reported within karst drainage, the extent to which this results from 16 hydrological dilution, rather than P retention, is poorly understood. This is of strategic importance 17 for understanding the resilience of karst landscapes to P inputs, given increasing pressures for 18 intensified agricultural production. Here, hydrochemical tracers were used to account for dilution of 19 P, and to quantify net P retention, along transport pathways between agricultural fields and 20 emergent springs, for the karst of the Ozark Plateau, mid-continent USA. Up to ~70% of the annual 21 total P flux and 90% of the annual soluble reactive P flux was retained, with preferential retention of 22 the most bioavailable (soluble reactive) P fractions. Our results suggest that, in some cases, karst 23 drainage may provide a greater P sink than previously considered. However, the subsequent 24 remobilization and release of the retained P may become a long-term source of slowly-released 25

Influence of legacy phosphorus, land use, and climate change on anthropogenic phosphorus inputs and riverine export dynamics

“…Previous studies indicated that 1-38 % of NAPI was exported by rivers (David and Gentry 2000;BorborCordova et al 2006;Russell et al 2008;Han et al 2011a, b;Sobota et al 2011), implying that the majority of NAPI was retained in soils, surface water sediments, and biomass Jarvie et al 2014), or even groundwater (Holman et al 2008;Roy and Bickerton 2014). This accumulated P, referred to as legacy P (i.e., surplus P stored in watershed landscapes that is derived from anthropogenic P inputs in previous years), is not addressed in the NAPI estimation, as well as the majority of current watershed models (Kleinman et al 2011).…”

“…The contribution of legacy P has been recognized as a major cause for failure to achieve water quality targets 20-30 years after implementing nutrient management measures for the Chesapeake Bay watershed, Mississippi River basin, Florida's inland and coastal waters, and Lake Erie basin (Meals et al 2010;Kleinman et al 2011;Jarvie et al 2013;Sharpley et al 2013;Condron et al 2013;Haygarth et al 2014). Legacy P release and delivery to rivers is highly dependent on landscape P saturation (Kleinman et al 2011;Jarvie et al 2014), hydrological connectivity (Gentry et al 2007;Han et al 2011a), and storm runoff/erosion (Borbor-Cordova et al 2006;Hong et al 2012). Therefore, from the perspective of changes in climate and land management, legacy P release may be enhanced and subsequently has the potential to make a considerable contribution to the riverine P flux.…”

Phosphorus distribution and sorption-release characteristics of the soil from newly submerged areas in the Danjiangkou reservoir, China

“…In order to judge whether the soil acts as a source or sink of P for the surface water (Pan et al, 2002), defined a criterion of = C/EPC 0 , and Jarvie defined EPC sat = ((EPC 0 − DIP)/EPC 0 ) × 100%, DIP (dissolved inorganic phosphate) (Jarvie et al, 2014). However, EPC 0 is in the denominator in both equations, both of the methods could easily enlarge the measurement error especially when EPC 0 is low.…”

Increased Effluent Dosage Effects on On-Site Wastewater Treatment Systems of Differing Architecture Type

“…However, much of the topography in northwest Arkansas is karstic [3] [4]. Consequently, groundwater resources are susceptible to pollution from sources such as fertilizers and OWTSs [5]. Therefore, it is important to study OWTS function and limitations within the local region in order to better understand various system types to prevent environmental contamination and human health risks.…”

“…Water in the perched water table could also move horizontally throughout the soil, exiting as springs, which could ultimately flow into larger streams, rivers, and lakes or reservoirs [12]. Consequently, contaminants present in the perched water table could also rise to the surface becoming point or non-point source pollution [5] [13].…”