Removal of nutrients in various types of constructed wetlands

The Science of The Total Environment, Journal Year: 2006, Volume and Issue: 380(1-3), P. 48 - 65

Published: Nov. 2, 2006

Language: Английский

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Phosphorus Legacy: Overcoming the Effects of Past Management Practices to Mitigate Future Water Quality Impairment

Journal of Environmental Quality, Journal Year: 2013, Volume and Issue: 42(5), P. 1308 - 1326

Published: Aug. 16, 2013

The water quality response to implementation of conservation measures across watersheds has been slower and smaller than expected. This led many question the efficacy these call for stricter land nutrient management strategies. In cases, this limited due legacies past activities, where sinks stores P along land-freshwater continuum mask effects reductions in edge-of-field losses P. Accounting legacy is important correctly apportion sources develop successful watershed remediation. study, we examined drivers at scale, specifically relation physical cascades biogeochemical spirals from soils rivers lakes via surface subsurface flow pathways. Terrestrial encompass prior activities that have built up soil levels exceed crop requirements modified connectivity between terrestrial fluvial transport. River lake a range processes control retention remobilization P, are linked sediment residence times. We provide case studies highlight major varying timescales which continues contribute receiving waters undermine restoration efforts, discuss how could be managed future programs.

Language: Английский

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Differences in Phosphorus and Nitrogen Delivery to The Gulf of Mexico from the Mississippi River Basin

Environmental Science & Technology, Journal Year: 2007, Volume and Issue: 42(3), P. 822 - 830

Published: Dec. 21, 2007

Seasonal hypoxia in the northern Gulf of Mexico has been linked to increased nitrogen fluxes from Mississippi and Atchafalaya River Basins, though recent evidence shows that phosphorus also influences productivity Gulf. We developed a spatially explicit structurally detailed SPARROW water-quality model reveals important differences sources transport processes control (N) (P) delivery Our simulations indicate agricultural watersheds contribute more than 70% delivered N P. However, corn soybean cultivation is largest contributor (52%), followed by atmospheric deposition (16%); whereas P originates primarily animal manure on pasture rangelands (37%), soybeans (25%), other crops (18%), urban (12%). The fraction in-stream load increases with stream size, but reservoir trapping causes large local- regional-scale delivery. results diversity management approaches required achieve efficient nutrient loads These include recognition P, role N, attention downstream reservoirs, better both close proximity rivers.

Language: Английский

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Hyporheic flow and transport processes: Mechanisms, models, and biogeochemical implications

Reviews of Geophysics, Journal Year: 2014, Volume and Issue: 52(4), P. 603 - 679

Published: Aug. 5, 2014

Fifty years of hyporheic zone research have shown the important role played by as an interface between groundwater and surface waters. However, it is only in last two decades that what began empirical science has become a mechanistic devoted to modeling studies complex fluid dynamical biogeochemical mechanisms occurring zone. These efforts led picture surface-subsurface water interactions regulators form function fluvial ecosystems. Rather than being isolated systems, bodies continuously interact with subsurface. Exploration processes new appreciation their wide reaching consequences for quality stream ecology. Modern aims toward unified approach, which are key elements appreciation, management, restoration whole river environment. In this unifying context, review summarizes results from field observations about flow transport describes theories proposed hydrology dynamics developed quantitatively model predict water, heat, dissolved suspended compounds sediment grain scale up watershed scale. The implications these biogeochemistry ecology also discussed.

Language: Английский

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Delivery and cycling of phosphorus in rivers: A review

The Science of The Total Environment, Journal Year: 2008, Volume and Issue: 400(1-3), P. 379 - 395

Published: Aug. 1, 2008

Language: Английский

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Global riverine N and P transport to ocean increased during the 20th century despite increased retention along the aquatic continuum

Biogeosciences, Journal Year: 2016, Volume and Issue: 13(8), P. 2441 - 2451

Published: April 27, 2016

Abstract. Various human activities – including agriculture, water consumption, river damming, and aquaculture have intensified over the last century. This has had a major impact on nitrogen (N) phosphorus (P) cycling in global continental waters. In this study, we use coupled nutrient-input–hydrology–in-stream nutrient retention model to quantitatively track changes freshwater N P cycles 20th Our results suggest that, during period, delivery streams increased from 34 64 Tg yr−1 5 9 yr−1. Furthermore, in-stream removal grew 14 27 3 One of causes is growing number reservoirs, which now account for 24 22 % retention/removal systems, respectively. increase could not balance rivers with consequence that transport ocean 19 37 2 4 Human also led molar : ratio bodies.

Language: Английский

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Do geographically isolated wetlands influence landscape functions?

Proceedings of the National Academy of Sciences, Journal Year: 2016, Volume and Issue: 113(8), P. 1978 - 1986

Published: Feb. 8, 2016

Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological habitat networks, contributing to landscape functions, such as flow generation, nutrient sediment retention, biodiversity support. GIWs constitute most of the many North American landscapes, provide a disproportionately large fraction wetland edges where functions are enhanced, form complexes water bodies create spatial temporal heterogeneity timing, paths, magnitude network connectivity. These attributes signal critical role for sustaining portfolio but legal protections remain weak despite preferential loss from landscapes. lack persistent surface connections, this condition does not imply absence hydrological, biogeochemical, biological exchanges nearby downstream waters. Although biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity limited evaporative solute enrichment suggest both generation retention. Similarly, whereas usually requires overland dispersal, numerous organisms, including rare threatened species, use waters at different times life stages, suggesting that mosaics. Indeed, weaker constrained precisely what enhances some GIW enables others. Based on analysis geography synthesis we argue conserving entire continuum connectivity, GIWs.

Language: Английский

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How does the Hedley sequential phosphorus fractionation reflect impacts of land use and management on soil phosphorus: A review

Journal of Plant Nutrition and Soil Science, Journal Year: 2009, Volume and Issue: 172(3), P. 305 - 325

Published: June 1, 2009

Abstract The Hedley sequential‐phosphorus (P)‐fractionation method has been used in many countries to study the effects of land‐use and management systems on soil P. Many data sets have obtained but collectively never considered or goal topic reviewed. Therefore, objectives this review were compile systematically evaluate these data. generated over years grouped into temperate, subtropical tropical soils different land use duration soil‐management studies. In natural ecosystems, vegetation types composition percent covers substantially affected all P fractions with pronounced impacts labile moderately short‐term studies (≤ 10 y), changes inorganic (P i ) detected when more ( e.g. , by factor 5) was applied than commonly recommended for agricultural crops. However, without application subtle temperate soils, declines significant soils. both climates, medium (10–25 y) long‐term (>25 cultivation depleted fractions, whereas most increased continuous application, regardless amount source Synthesis resulted multiple‐regression functions which described differences as function experiments. Moreover, correlation analysis also showed strong association among fractions. Current limitations interpretation fractionation can be overcome 31 nuclear–magnetic resonance (NMR) X‐ray absorption near‐edge fine‐structure (XANES) spectroscopy.

Language: Английский

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Key factors influencing differences in stream water quality across space

Wiley Interdisciplinary Reviews Water, Journal Year: 2017, Volume and Issue: 5(1)

Published: Oct. 24, 2017

Globally, many rivers are experiencing declining water quality, for example, with altered levels of sediments, salts, and nutrients. Effective quality management requires a sound understanding how why differs across space, both within between river catchments. Land cover, land use, management, atmospheric deposition, geology soil type, climate, topography, catchment hydrology the key features that affect: (1) amount suspended sediment, nutrient, salt concentrations in catchments (i.e., source), (2) mobilization ,and (3) delivery these constituents to receiving waters. There are, however, complexities relationship landscape characteristics stream quality. The strength this can be influenced by distance spatial arrangement constituent sources catchment, cross correlations characteristics, seasonality. A knowledge gap should addressed future studies is interactions characteristics. currently limited relationships responses shift based on other catchment. Understanding forces driving necessary development successful strategies. This could used develop predictive models, which would aid forecasting riverine WIREs Water 2018, 5:e1260. doi: 10.1002/wat2.1260 article categorized under: Science > Hydrological Processes Quality

Language: Английский

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Valuing ecosystem services from wetlands restoration in the Mississippi Alluvial Valley

Ecological Economics, Journal Year: 2010, Volume and Issue: 69(5), P. 1051 - 1061

Published: Jan. 9, 2010

Language: Английский

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