Bayesian chemistry-assisted hydrograph separation (BACH) and nutrient load partitioning from monthly stream phosphorus and nitrogen concentrations

Woodward, S.L.; Stenger, Roland

doi:10.1007/s00477-018-1612-3

Cited by 12 publications

(9 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As mentioned above, our predictor variables were largely unable to explain variation in N-retention. Other studies have focused on the interaction of catchment characteristics such as biogeochemistry 23 , and catchment management such as point sources, agricultural intensification 17 , 24 and flow-paths 8 , 25 . In contrast to these studies, our catchments were more diverse in altitude, geology, and land use intensity (Table 1 ), and had little point source contributions 26 .…”

Section: Discussionmentioning

confidence: 99%

“…Determining lag times is difficult, often hindered by infrequent data sampled over short time frames 6 . Much more is known for deep groundwater, with typical lags up to decades 7 , but often the greatest nitrate contributions are associated with shallow groundwater or surface runoff pathways 8 , 9 , with lags ranging from about 1 to 10 years 10 . Disentangling flow paths requires extensive data and modelling which are both time consuming and expensive 10 , 11 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

The implications of lag times between nitrate leaching losses and riverine loads for water quality policy

McDowell

Simpson

Ausseil

et al. 2021

Sci Rep

View full text Add to dashboard Cite

Understanding the lag time between land management and impacts on riverine nitrate–nitrogen (N) loads is critical to understand when action to mitigate nitrate–N leaching losses from the soil profile may start improving water quality. These lags occur due to leaching of nitrate–N through the subsurface (soil and groundwater). Actions to mitigate nitrate–N losses have been mandated in New Zealand policy to start showing improvements in water quality within five years. We estimated annual rates of nitrate–N leaching and annual nitrate–N loads for 77 river catchments from 1990 to 2018. Lag times between these losses and riverine loads were determined for 34 catchments but could not be determined in other catchments because they exhibited little change in nitrate–N leaching losses or loads. Lag times varied from 1 to 12 years according to factors like catchment size (Strahler stream order and altitude) and slope. For eight catchments where additional isotope and modelling data were available, the mean transit time for surface water at baseflow to pass through the catchment was on average 2.1 years less than, and never greater than, the mean lag time for nitrate–N, inferring our lag time estimates were robust. The median lag time for nitrate–N across the 34 catchments was 4.5 years, meaning that nearly half of these catchments wouldn’t exhibit decreases in nitrate–N because of practice change within the five years outlined in policy.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

The implications of lag times between nitrate leaching losses and riverine loads for water quality policy

McDowell

Simpson

Ausseil

et al. 2021

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Although flow was not continuously measured in the Kopuhurihuri Stream, a continuous record was available c 1 km downstream of the confluence of the Kopuhurihuri and the larger Waiotapu Stream site since 1962. Streamflow in the Waiotapu Stream catchment is relatively stable with chemistry-assisted hydrograph separation suggesting on average 64% is slow flow (deep groundwater), 24% is medium flow (shallow groundwater), and 13% is fast flow (nearsurface pathways) (Woodward and Stenger 2018); modelling by Piper (2005) Non-welded ignimbrite (181AD Taupo erupƟon), or middle Pleistocene rhyolite (0.128-0.524M yrs old). All other lithology outside of this area is mapped as late Pleistocene river deposits (0.012-0.027 million years old) At each site, samples of sediment (0.2 kg wet weight) were taken either by a shovel of the top 2 cm or a 5 cm diameter corer of the 20-40 and 40-80 cm depths from five locations at each site.…”

Section: Site Characteristics and Samplingmentioning

confidence: 99%

Likely controls on dissolved reactive phosphorus concentrations in baseflow of an agricultural stream

2020

Self Cite

View full text Add to dashboard Cite

Purpose High baseflow phosphorus (P) concentrations increase the likelihood of periphyton blooms. Several physical and chemical factors can control baseflow P concentrations such as hydraulic exchange with groundwater, particle size-sorting, redox chemistry and different sediment sources. We hypothesized that of these sources, anoxic sediments would allow P-rich groundwater to influence baseflow P concentrations the most and that the measurement of the equilibrium P concentration (EPC 0) of sediments under oxic conditions would not predict P release in anaerobic sediment or baseflow P concentrations. Materials and methods At four locations along an agricultural stream, we measured dissolved reactive P (DRP), pH, iron, manganese, sulphate, nitrate and dissolved oxygen in streamflow and hyporheic water at 0-200, 200-400 and 400-800 mm depths and P fractions and EPC 0 in sediment samples from the 0-200, 200-400 and 400-800 mm depths. Results and discussion Concentrations of DRP in streamflow and shallow hyporheic zone water increased downstream and were mirrored by concentrations in shallow sediment, EPC 0 measurements of oxic sediments and deeper hyporheic waters. Groundwater samples and the EPC 0 in deeper sediments did not show a pattern or residence time consistent with the supply of P to baseflow despite deeper sediment being anoxic and less likely to sorb upwelling P. There was also no change in pH or particle size downstream ruling out the degassing of groundwater or sediment size-sorting as an influence. However, the composition of sediment and underlying lithology of the catchment pointed to sediment downstream that was different to upstream sediment in that it could store and release more P. Conclusions Given the strong influence of sediment source on baseflow P concentrations, efforts to decrease the likelihood of periphyton blooms under baseflow should focus on reducing the erosion of P-rich sediment. Furthermore, the presence of oxic conditions in surface sediment meant that there was a relationship between EPC 0 and hyporheic water P concentrations. However, mixed oxic/anoxic conditions in deeper layer may require EPC 0 , or release rates, to be measured under reducing conditions.

show abstract

“…To model the likelihood of water quality impairment by periphyton growth, detailed information is required not only about the state of nutrient concentrations during the growth period, but also about factors involved in the loss of N and P from land to water, such as precipitation, soil type and land use 25,26 . There are many models that can predict the concentration, load and yield of N and P at a catchment scale 27,28 and a few that can predict the load and yield of N and P at a regional or global scale 29,30 . However, models that can predict N and P concentrations at a global scale remain elusive.…”

mentioning

confidence: 99%

Global mapping of freshwater nutrient enrichment and periphyton growth potential

McDowell

Noble

Pletnyakov

et al. 2020

Sci Rep

View full text Add to dashboard Cite

periphyton (viz. algal) growth in many freshwater systems is associated with severe eutrophication that can impair productive and recreational use of water by billions of people. However, there has been limited analysis of periphyton growth at a global level. to predict where nutrient over-enrichment and undesirable periphyton growth occurs, we combined several databases to model and map global dissolved and total nitrogen (N) and phosphorus (P) concentrations, climatic and catchment characteristics for up to 1406 larger rivers that were analysed between 1990 and 2016. We predict that 31% of the global landmass contained catchments may exhibit undesirable levels of periphyton growth. Almost three-quarters (76%) of undesirable periphyton growth was caused by P-enrichment and mapped to catchments dominated by agricultural land in North and South America and Europe containing 1.7B people. In contrast, undesirable periphyton growth due to N-enrichment was mapped to parts of North Africa and parts of the Middle East and India affecting 280 M people. The findings of this global modelling approach can be used by landowners and policy makers to better target investment and actions at finer spatial scales to remediate poor water quality owing to periphyton growth. Periphyton contains a broad range of algae, cyanobacteria, heterotrophic microbes, and detritus that grows on the beds of streams and rivers. Some species of cyanobacterial algae can be toxic, while the excessive growth and subsequent death and decay of toxic and non-toxic species can deplete oxygen, clog the hyporheic zone and alter pH 1. These changes can impair the reproductive capacity or even kill fish and bottom-dwelling animals, taint potable water supply and reduce the aesthetic and recreational quality of streams and rivers 2. These effects, commonly termed eutrophication, put aquatic biodiversity and ecosystem function at risk and globally, cost billions of dollars annually to remediate 3,4. To target efforts to remediate periphyton growth, information is required on where periphyton grows, how much grows, is the level of growth acceptable and what controls growth. This information is commonly available at a site or catchment-scale, but seldom available at a regional or national scale. To our knowledge, no global analysis exists. The controlling factors important in periphyton growth include light, temperature, flow rates and nutrient concentrations and bioavailability 5-8. In most streams and rivers, little can be done about altering light, temperature or flow rates to minimise periphyton growth, therefore most attention focuses the relative concentrations and bioavailability of nitrogen (N) and phosphorus (P), although in some system carbon may also be important 9,10. The ratio of N to P has been found to limit growth, not only in periphyton but also in microbes and terrestrial fauna and freshwater algae 11,12. Originally described as a molar ratio of carbon (C), N and P of 106:16:1 13 , in marine phytoplankton, the ratio reduces to N and P in freshw...

show abstract

Bayesian chemistry-assisted hydrograph separation (BACH) and nutrient load partitioning from monthly stream phosphorus and nitrogen concentrations

Cited by 12 publications

References 72 publications

The implications of lag times between nitrate leaching losses and riverine loads for water quality policy

The implications of lag times between nitrate leaching losses and riverine loads for water quality policy

Likely controls on dissolved reactive phosphorus concentrations in baseflow of an agricultural stream

Global mapping of freshwater nutrient enrichment and periphyton growth potential

Contact Info

Product

Resources

About