Journal articles: 'Dissolved reactive phosphorus'

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Matula, J. "Determination of dissolved reactive and dissolved total phosphorus in water extract of soils." Plant, Soil and Environment 57, No. 1 (January 14, 2011): 1–6. http://dx.doi.org/10.17221/185/2010-pse.

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The simplified acid peroxydisulphate digestion of soil water extract was evaluated for determination of total dissolved phosphorus by molybdenum-blue colorimetry in comparison with direct P-detection in water extract by the ICP-AES technique. The research was conducted on 79 agricultural soils with different agrochemical characteristics. The results of the colorimetric P detection in water extract without digestion and ICP phosphorus detection were different. The median of values determined by ICP-AES was 1.7 times higher than that of colorimetry, but the correlations between the two measurements were quite close (r = 0.993). Differences between the colorimetric phosphorus and ICP-AES phosphorus were irregular, increasing as the phosphorus level in soils decreased. The simplified procedure of acid peroxydisulphate digestion is useful for routine determination of total water-extracted phosphorus in soils when the soil testing laboratory is not equipped with the ICP-AES technique. The two-tailed paired t-test did not prove any difference in the values between the direct ICP-AES P-detection in water extract of soils and colorimetric P-detection in the acid peroxydisulphate digest.  

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Priha, Maarit. "Bioavailability of Pulp and Paper Mill Effluent Phosphorus." Water Science and Technology 29, no. 5-6 (March 1, 1994): 93–103. http://dx.doi.org/10.2166/wst.1994.0705.

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The aim of this study was to examine the stability and bioavailability of different phosphorus fractions of pulp and paper mill effluents in order to assess the environmental benefits of reducing their phosphorus discharges. Two types of effluent were studied: activated sludge treated bleached kraft mill effluent and activated sludge treated paper mill effluent. Phosphorus was characterized on the basis of its solubility and chemical reactivity. The stability of particulate phosphorus was studied in long-term (6-8 weeks) degradation tests. The bioavailability of different phosphorus fractions was measured by algal growth potential tests. In bleached kraft mill effluent (BKME) the proportion of dissolved phosphorus in relation to the total phosphorus was on an average 80%, and of this, approximately 80-90% was reactive phosphorus. During a 6-8 week incubation period some 60-70% of the particulate phosphorus in BKME was dissolved as soluble phosphorus, and most of it was of the reactive type. Approximately 90% of the dissolved phosphorus and 45% of the particulate phosphorus in BKME was biologically available phosphorus (BAP). Altogether some 80% of the total phosphorus in activated sludge treated BKME was available for algae either immediately or after inherent degradation. The percentages of dissolved and particulate phosphorus of paper mill effluent (PME) total phosphorus were of the same order of magnitude as those of BKME, but less than 20% of the dissolved phosphorus was of the reactive type. Approximately 50-60% of the particulate phosphorus in PME was dissolved in degradation tests, and 90% of it was biologically available.

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Wang, Y. T., T. Q. Zhang, I. P. O'halloran, C. S. Tan, and Q. C. Hu. "Predicting environmental soil phosphorus limits for dissolved reactive phosphorus loss." Soil Use and Management 32, no. 1 (December 22, 2015): 60–68. http://dx.doi.org/10.1111/sum.12238.

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Wu, Lingling, and Youngsook Huh. "Dissolved reactive phosphorus in large rivers of East Asia." Biogeochemistry 85, no. 3 (July 27, 2007): 263–88. http://dx.doi.org/10.1007/s10533-007-9133-z.

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Wang, Jing Fu, Jing An Chen, and Yong Qiong Yang. "Seasonal Stratification and Phosphorus Release from Sediments at Lake Hongfeng, Southwestern Plateau, China." Applied Mechanics and Materials 448-453 (October 2013): 299–305. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.299.

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This study investigated the relation between seasonal stratification and sediment phosphorus release in a seasonally stratified lake. Lake quality monitoring was conducted for 10 months from April 2010 to January 2011 in Lake Hongfeng, southwestern China. Destratification generated strong mixing from surface to bottom waters in the early autumn. The lake water was well-mixed vertically within 3 days and became anoxic within next few months. Total phosphorus concentrations of the whole water column increased by 15-20% as a result of high surface sediment concentrations of total phosphorus and reactive phosphorus. In seasonally stratified lakes, high reactive phosphorus content in sediments may form a larger flux of dissolved phosphorus in the sedimentwater interface following turnover. Technical measures should be taken to increase dissolved oxygen concentration and control the water circulation in this lake, especially during the cooling period, to weaken the effect of destratification and prevent sediment phosphorus release.

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Watkins, Mark, Hayley Castlehouse, Murray Hannah, and David M. Nash. "Nitrogen and Phosphorus Changes in Soil and Soil Water after Cultivation." Applied and Environmental Soil Science 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/157068.

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Untilled dairy pasture has the potential to release more phosphorus to the environment than a regularly ploughed pasture. In this paper we report the initial results of a study comparing the effects of cultivation, phosphorus (P) fertiliser (10, 35, and 100 kg P/ha), and two types of vegetation (ryegrass (Lolium perenne) or ryegrass mixed with clover (Trifolium repens)) in a randomised complete block design. Phosphorus was measured in soil samples taken from depths of 0–20 mm and 0–100 mm. Waters extracted from the 0–20 mm samples were also analysed. In all cases, the P concentrations (Olsen P, Colwell P, Total P, CaCl2extractable P, Dissolved Reactive P, and Total Dissolved P) in the top 20 mm declined with ploughing. Dissolved Reactive P measured in the soil water was 70% less overall in the ploughed plots compared with the unploughed plots, and by 35 weeks after P treatments the decrease in Dissolved Reactive P was 66%. The effects of the fertiliser and pasture treatments were inconclusive. The data suggest that ploughing can lower the risk of P exports from intensive dairy farms in the trial area.

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Ma, Jian, Quanlong Li, and Dongxing Yuan. "Loop flow analysis of dissolved reactive phosphorus in aqueous samples." Talanta 123 (June 2014): 218–23. http://dx.doi.org/10.1016/j.talanta.2014.02.020.

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Sale, Peter W. G. "Preface to 'Role of Reactive Phosphate Rock Fertilisers for Pastures in Australia'." Australian Journal of Experimental Agriculture 37, no. 8 (1997): I. http://dx.doi.org/10.1071/eav37n8_pr.

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Summary. The dissolution of North Carolina phosphate rock (NCPR) in soil was investigated in a laboratory study using surface soils sampled from 28 permanent pasture sites. The relationships between phosphorus (P) dissolved, P availability and various soil properties were investigated using simple and multiple linear regression and the findings related to the relative effectiveness of NCPR for pasture production at the sites. The extent of dissolution of NCPR was positively correlated to P buffering capacity (r2 = 0.42). Phosphorus buffering capacity and titratable acidity together accounted for 72% of the variance in dissolution. Bicarbonate-extractable P (‘available’ P) generally increased as dissolution increased. However, the increase in available P was consistently lower for soils with higher P buffering capacity. The proportion of dissolved P that was available also decreased with increasing P buffering capacity (r2 = 0.63). Consequently, the increase in available P was highest for soils with very low to low P buffering capacity. This suggests that the effectiveness of NCPR as a fertiliser may be more closely related to the availability of dissolved P, than to the amount of NCPR dissolved in a soil. Consistent with this laboratory finding, the agronomic effectiveness of NCPR relative to superphosphate measured in the field tended to decrease with increasing P buffering capacity. The agronomic effectiveness of NCPR was comparable with superphosphate only at certain sites, and with some noted exceptions, most of these had surface soils with very low to low P buffering capacity. The high relative effectiveness of NCPR at these sites was mostly attributed to the loss of superphosphate by leaching. Since NCPR dissolves much more slowly than superphosphate, only a small amount of the P applied as NCPR would be lost during leaching events. Slow dissolution of the remaining NCPR probably supplied a small amount of dissolved P over an extended period of time, and due to the low P buffering capacity, much of this was available to plants.

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Cooke, Sandra E., and Ellie E. Prepas. "Stream phosphorus and nitrogen export from agricultural and forested watersheds on the Boreal Plain." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 10 (October 1, 1998): 2292–99. http://dx.doi.org/10.1139/f98-118.

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We evaluated phosphorus (P) and inorganic nitrogen (IN) export from two agricultural and two forested watersheds on the nutrient-rich but relief-poor Boreal Plain. One agricultural stream was in a watershed that contained cropland, while the second consisted of mixed agricultural activities. Over the 2-year study, total dissolved phosphorus (TDP) concentrations were proportionately high, particularly in the agricultural streams. Flow-weighted TDP averaged 82% of the total phosphorus (TP) in the agricultural streams and 43% in the forested streams. In all watersheds, TDP was almost exclusively dissolved reactive phosphorus and most of the annual P export was in summer. The type of agricultural activity in the watershed influenced IN speciation; in the mixed agricultural watershed, 94% of IN export was ammonium, whereas 98% of IN load was nitrate from the cropland watershed. Disproportionately high TDP to TP export from agricultural watersheds suggests that, in areas of low relief and relatively high soil water P content, land clearing may influence dissolved more than particulate phosphorus export.

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10

Xu, Qing, Xiaoping Yu, Yafei Guo, Tianlong Deng, Yu-Wei Chen, and Nelson Belzile. "Seasonal Variations of Phosphorus Species in the Overlying and Pore Waters of the Tuohe River, China." Journal of Chemistry 2019 (October 30, 2019): 1–9. http://dx.doi.org/10.1155/2019/6727239.

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Overlying sediment and pore waters were collected in summer and winter at upstream (Jintang) and downstream (Neijiang) sites of the Tuohe River, which is one of the five largest tributaries of the Yangtze River in China. Phosphorus species, including soluble reactive phosphorus (SRP), soluble unreactive phosphorus (SUP), and total dissolved phosphorus (TDP), and some diagenetic constituents including dissolved Fe(II), Mn(II), and sulfide in overlying and pore waters, were measured systematically. The seasonal variations and vertical distributions of phosphorus species in overlying and pore waters at both sampling sites were obtained to elucidate some aspects of the transport and transformations of phosphorus. Based on the profiles of pore and overlying waters as well as the TDN/TDP data during an algal bloom in 2007, it was clearly demonstrated that phosphorus was the main factor limiting the phytoplankton growth in the Tuohe River.

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Scrimgeour, Garry J., and Patricia A. Chambers. "Cumulative effects of pulp mill and municipal effluents on epilithic biomass and nutrient limitation in a large northern river ecosystem." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 7 (July 1, 2000): 1342–54. http://dx.doi.org/10.1139/f00-057.

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Large-scale patterns in epilithic biomass and nutrient status were evaluated at 33 sites located upstream and downstream of point-source anthropogenic effluents in the Athabasca and Wapiti-Smoky rivers in Alberta, Canada. Multiple regression showed that epilithic chlorophyll a was significantly (p < 0.0001) related to concentrations of dissolved inorganic nitrogen and marginally (p = 0.06) significantly related to soluble reactive phosphorus. Epilithic biomass was up to 50 times higher immediately downstream of point-source inputs compared with sites upstream and those 20-150 km downstream. Data from nutrient diffusing substrata showed that the epilithon at 18 of the 33 sites was nutrient limited, while 14 sites showed no nutrient limitation; interpretation of the remaining site was inconclusive. Of the 18 nutrient-limited sites, six were nitrogen limited, five were phosphorus limited, and seven were co-limited. Multiple discriminant function analysis showed that the combined concentration of soluble reactive phosphorus and dissolved inorganic nitrogen was a significant discriminator between deplete and replete sites.

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Welikhe, P., S. M. Brouder, J. J. Volenec, M. Gitau, and R. F. Turco. "Dynamics of dissolved reactive phosphorus loss from phosphorus source and sink soils in tile-drained systems." Journal of Soil and Water Conservation 77, no. 1 (October 28, 2021): 1–14. http://dx.doi.org/10.2489/jswc.2022.00012.

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13

B. J. Baker, K. W. King, and H. A. Torbert. "Runoff Losses of Dissolved Reactive Phosphorus from Organic Fertilizer Applied to Sod." Transactions of the ASABE 50, no. 2 (2007): 449–54. http://dx.doi.org/10.13031/2013.22659.

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14

Iqbal, R., S. Akimoto, K. Tokutake, T. Inoue, and H. Tachibana. "Water chemistry gradient in a degraded bog area." Water Science and Technology 53, no. 2 (January 1, 2006): 63–71. http://dx.doi.org/10.2166/wst.2006.039.

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Surface and ground water was sampled in a degraded bog area 36 times during 1993–2003 at Five representative points: point E (natural area with Sphagnum as the main vegetal cover), point W (boundary between the natural and degraded areas), point W' (area installed with vinyl sheeting), point WW (area where Sasa thrives), and point NC (area with naturally formed ditches). Analysis of variance (ANOVA) was conducted for parameters measured in surface water and ground water at 0.5, 1.0, 1.5, and 2.0 m depths. “Sampling point” (i.e. locations along the degradation gradient) accounted for most of the variation in surface and ground water chemistry. It accounted for 30–80% of the total variation in pH, electrical conductivity, ammonia, dissolved nitrogen, major cations (Na+, K+, Ca2+ , Mg2+ ), alkalinity and dissolved organic carbon. “Year” accounted for more variation in nitrate, nitrite, chloride, and sulfate than the sampling point did, but the variation in dissolved reactive phosphorus and dissolved phosphorus concentrations was not based on any of the calculated variables.

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McEachern, P., E. E. Prepas, J. J. Gibson, and W. P. Dinsmore. "Forest fire induced impacts on phosphorus, nitrogen, and chlorophyll a concentrations in boreal subarctic lakes of northern Alberta." Canadian Journal of Fisheries and Aquatic Sciences 57, S2 (September 7, 2000): 73–81. http://dx.doi.org/10.1139/f00-124.

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The biogeochemistry of 10 headwater lakes in burnt peatland-conifer catchments and 14 in unburnt catchments was evaluated throughout a summer 2 years following forest fire in a boreal subarctic region of northern Alberta. Cation exchange within burnt catchments resulted in proton flux and a 9% reduction in mean pH. Lakes in burnt catchments contained more than twofold higher (P << 0.01) mean concentrations of total, total dissolved, and soluble reactive phosphorus, 1.5-fold higher (P << 0.01) concentrations of dissolved organic carbon, and more than 1.2-fold higher (P < 0.05) concentrations of total and total dissolved nitrogen, nitrate + nitrite, and ammonium compared with reference lakes. Total phosphorus concentration explained 86% of the variance in reference lake chlorophyll concentration but was not related to chlorophyll concentration in burnt lakes. Analysis of chlorophyll - total phosphorus residuals suggested that algae in burn-impacted lakes were light limited. With the addition of five lakes burnt between 1961 and 1985, time since disturbance and percent disturbance combined explained 74% of the variance in total phosphorus among burnt lakes. Fire caused increased flux of materials to the study lakes with slow recovery over decades.

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Ran, Xiang-bin, Hong-tao Chen, Jun-feng Wei, Qing-zhen Yao, Tie-zhu Mi, and Zhi-gang Yu. "Phosphorus speciation, transformation and retention in the Three Gorges Reservoir, China." Marine and Freshwater Research 67, no. 2 (2016): 173. http://dx.doi.org/10.1071/mf14344.

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Damming of river systems allowing the transformation of former rivers into artificial lakes will increase the transformation and retention of dissolved and sediment-associated phosphorus (P). The reservoir is therefore a ‘filter’ or ‘converter’, reducing and delaying the transport of nutrients to marine systems. Our study of the Three Gorges Reservoir (TGR) found that no stratification of phosphorus occurred, and the high particulate phosphorus (PP) concentrations upstream decreased gradually in the reservoir. Detrital P was found in greater concentrations in the surface sediment, accounting for 39% of PP; exchangeable P was rare and contributed very little to the total P budget. P forms and their concentrations in the suspended particulate matter varied throughout the TGR, with a significant increase of bioavailable P in the <8-μm particle fraction from 27% of PP in Fuling to 60% in Yichang, and decreasing detrital P and authigenic P in each grain size class. The TGR acted as a ‘converter’ for the dissolved reactive phosphorus, and it therefore plays a minor role in trapping incoming total dissolved phosphorus; whereas the TGR behaved as a ‘filter’ for the PP, especially for the coarse fraction, which resulted in the retention of 70% of the non-bioavailable PP. The controlling mechanism of P species and retention in the reservoir is particulate settling and its associated effects.

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Mchau, Geofrey J., Edna Makule, Revocatus Machunda, Yun Yun Gong, and Martin Kimanya. "Phycocyanin as a proxy for algal blooms in surface waters: case study of Ukerewe Island, Tanzania." Water Practice and Technology 14, no. 1 (January 8, 2019): 229–39. http://dx.doi.org/10.2166/wpt.2019.005.

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Abstract Knowledge of the parameters that contribute to water body eutrophication is essential for proper monitoring and management of water quality for human consumption. This study assessed water quality parameters in relation to phycocyanin (PC) as a proxy indicator for harmful algal blooms (HABs). Samples were collected from 23 water sources – lakes, wells, springs and boreholes – in selected villages, for six months. Parameters measured included temperature, pH, redox potential, dissolved oxygen, electrical conductivity, total dissolved solids, nitrate nitrogen, nitrite nitrogen, phosphorus, reactive phosphate and total chlorophyll, which were related to (PC) occurrence. The PC concentration detected in Lake Victoria ranged from 5 to 58.4 μg/l above the WHO alert level and exceeded that in other water sources by almost 30 μg/l (P < 0.001). Univariate relationship between water quality parameters and PC indicates association with temperature, redox potential, total chlorophyll, nitrate nitrogen, nitrite nitrogen, phosphate and reactive phosphorus (P < 0.001). The multivariate model indicates that redox potential, nitrate nitrogen and phosphorus are significant statistically (P < 0.05). A predictive model indicates that nitrate nitrogen and reactive phosphorus contribute significantly to PC occurrence whereby unit (1 mg/l) increases in these parameters increase PC by 9.55 and 4.38 μg/l (P < 0.05) respectively. This study demonstrates that water quality parameters can be used to predict increases in PC and hence as a proxy for HABs. It remains important to be able to classify algal blooms, to understand which species are present and their potential cyanotoxin production.

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Wade, A. J., P. G. Whitehead, and D. Butterfield. "The Integrated Catchments model of Phosphorus dynamics (INCA-P), a new approach for multiple source assessment in heterogeneous river systems: model structure and equations." Hydrology and Earth System Sciences 6, no. 3 (June 30, 2002): 583–606. http://dx.doi.org/10.5194/hess-6-583-2002.

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Abstract. A new model has been developed for assessing the effects of multiple sources of phosphorus on the water quality and aquatic ecology in heterogeneous river systems. The Integrated Catchments model for Phosphorus (INCA-P) is a process-based, mass balance model that simulates the phosphorus dynamics in both the plant/soil system and the stream. The model simulates the spatial variations in phosphorus export from different land use types within a river system using a semi-distributed representation, thereby accounting for the impacts of different land management practices, such as organic and inorganic fertiliser and wastewater applications. The land phase of INCA-P includes a simplified representation of direct runoff, soilwater and groundwater flows, and the soil processes that involve phosphorus. In addition, the model includes a multi-reach in-stream component that routes water down the main river channel. It simulates Organic and Inorganic Phosphorus concentrations in the land phase, and Total Phosphorus (dissolved plus particulate phosphorus) concentrations in the in-stream phase. In-stream Soluble Reactive Phosphorus concentrations are determined from the Total Phosphorus concentrations and the macrophyte, epiphyte and algal biomasses are simulated also. This paper describes the model structure and equations, the limitations and the potential utility of the approach. Keywords: modelling, water quality, phosphorus, soluble reactive phosphorus, basin management

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TUENGEUN, O., P. ELLIS, I. MCKELVIE, P. WORSFOLD, J. JAKMUNEE, and K. GRUDPAN. "Determination of dissolved reactive phosphorus (DRP) and dissolved organic phosphorus (DOP) in natural waters by the use of rapid sequenced reagent injection flow analysis." Talanta 66, no. 2 (April 15, 2005): 453–60. http://dx.doi.org/10.1016/j.talanta.2004.12.032.

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UUSITALO, R., and H. JANSSON. "Dissolved reactive phosphorus in runoff assessed by soil extraction with an acetate buffer." Agricultural and Food Science 11, no. 4 (January 4, 2002): 343–53. http://dx.doi.org/10.23986/afsci.5734.

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Agronomic soil test phosphorus (STP) data is, in addition to fertility studies, increasingly utilised in environmental risk assessment. We compared relationships between soil P extracted by acid ammonium acetate (AAAc-P) and water-soluble P (Pw) in laboratory, and AAAc-P and dissolved molybdatereactive P (DRP) in field runoff. The laboratory study suggested a close relationship (R2 = 0.87, n = 64) between AAAc-P and soluble P concentration in 1:100 (w/v) soil-to-water extracts, described by a linear equation:Pw (mg l1) =0.021 × AAAc-P (mg l1 soil) 0.015 (mg l1). In Lake Rehtijärvi cathcment, dominated by clayey soils, the AAAc-P content of field Ap horizon in a similar manner influenced the flow-weighted DRP concentration in surface runoff and drainflow:a 1 mg l1 increase in soil AAAc-P corresponded to 0.015 and 0.018 mg l1 increase in surface runoff and drainflow DRP, respectively. When the AAAc-P vs.Pw relationship obtained in the laboratory test was used to predict the average DRP concentration in edge-of-field runoff, the precision of the DRP estimates inferred from STP data was in 95% of the cases ± 0.10 mg l1. In the L. Rehtijärvi catchment, 50% of the diffuse DRP loading risk was assigned to an area that corresponded to less than 20% of the fields and the situation may be similar in the national scale.;

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Wang, Y. T., T. Q. Zhang, Q. C. Hu, C. S. Tan, I. P. O' Halloran, C. F. Drury, D. K. Reid, et al. "Estimating Dissolved Reactive Phosphorus Concentration in Surface Runoff Water from Major Ontario Soils." Journal of Environmental Quality 39, no. 5 (September 2010): 1771–81. http://dx.doi.org/10.2134/jeq2009.0504.

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River, Mark, and Curtis J. Richardson. "Dissolved Reactive Phosphorus Loads to Western Lake Erie: The Hidden Influence of Nanoparticles." Journal of Environmental Quality 48, no. 3 (May 2019): 645–53. http://dx.doi.org/10.2134/jeq2018.05.0178.

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Abel-Denee, Marco, Cigdem Eskicioglu, and Giampiero Galvagno. "Using Heterogeneous Nucleation to Remove Non-Reactive Dissolved Phosphorus from Sludge Dewatering Centrate." Proceedings of the Water Environment Federation 2017, no. 3 (January 1, 2017): 196–209. http://dx.doi.org/10.2175/193864717821494736.

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Kjær, Helle Astrid, Paul Vallelonga, Anders Svensson, Magnus Elleskov L. Kristensen, Catalin Tibuleac, and Matthias Bigler. "Continuous Flow Analysis Method for Determination of Dissolved Reactive Phosphorus in Ice Cores." Environmental Science & Technology 47, no. 21 (October 15, 2013): 12325–32. http://dx.doi.org/10.1021/es402274z.

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Bauwe, Andreas, Kai-Uwe Eckhardt, and Bernd Lennartz. "Predicting dissolved reactive phosphorus in tile-drained catchments using a modified SWAT model." Ecohydrology & Hydrobiology 19, no. 2 (April 2019): 198–209. http://dx.doi.org/10.1016/j.ecohyd.2019.03.003.

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McDowell, Richard W., Craig Depree, and Roland Stenger. "Likely controls on dissolved reactive phosphorus concentrations in baseflow of an agricultural stream." Journal of Soils and Sediments 20, no. 8 (May 6, 2020): 3254–65. http://dx.doi.org/10.1007/s11368-020-02644-w.

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Molisani, MM, H. Becker, HS Barroso, CAG Hijo, TM Monte, GH Vasconcellos, and LD Lacerda. "The influence of castanhão reservoir on nutrient and suspended matter transport during rainy season in the ephemeral Jaguaribe river (CE, Brazil)." Brazilian Journal of Biology 73, no. 1 (February 2013): 115–23. http://dx.doi.org/10.1590/s1519-69842013000100013.

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Measurements of nutrient and suspended matter concentrations and loads entering and leaving the Castanhão reservoir during the rainy season were carried out to assess the influence of this large reservoir on land-sea fluvial transport in the ephemeral Jaguaribe river basin. Spatial variation indicated statistically significant attenuation of concentrations only for total phosphorous and suspended matter across the reservoir. Strong retention of nutrients and suspended matter loads by the reservoir was observed with average trapping efficiency of 89% for dissolved silicon, 98% of soluble reactive phosphorus, 71% for ammonium, 87% for total nitrogen, 98% for total phosphorus and 97% for suspended matter compared to the reservoir inflow. The dam operational procedure defined by the ephemeral conditions of the river reduced water releases compared to reservoir inflow and induced strong retention of nutrient and suspended matter loads within the reservoir when fluvial transfer occurs in this semiarid watershed.

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Rodrigues, Luzia Cleide, Sueli Train, Maria do Carmo Roberto, and Thomaz Aurélio Pagioro. "Seasonal fluctuation of some limnological variables on a floodplain lake (Patos lagoon) of the Upper Paraná River, Mato Grosso do Sul State, Brazil." Brazilian Archives of Biology and Technology 45, no. 4 (December 2002): 499–513. http://dx.doi.org/10.1590/s1516-89132002000600014.

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Temporal variations of some limnological variables in limnetic and littoral regions of Patos lagoon, a "várzea" lake on the floodplain of the Upper Paraná River (22(0) 43'12"S e 53(0) 17'37"W), were studied in relation to hydrological and climatological factors. Measurements of water temperature, euphotic zone, suspended material, electrical conductivity, total alkalinity, pH, dissolved oxygen, carbon dioxide, total nitrogen, total Kjeldahl nitrogen, total phosphorus, dissolved phosphorus, reactive soluble phosphorus and chlorophyll a were taken monthly between March 1993 and February 1994. Results lend evidence to the importance of the hydrological regime on the dynamic of limnological variables in floodplain lakes. A dilution of nutrients in the lagoon, especially phosphates, occurred during floods. This was followed by fertilization of the environment by nutrients from the inundated marginal regions. During low connectivity periods, autochthonous, events such as ressuspension of sediment, brought on by wind and rain, governed limnological events in the lagoon.

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Witt, P. Ch, F. Grabowski, and H. H. Hahn. "Interactions between biological and physico-chemical mechanisms in biological phosphate elimination." Water Science and Technology 30, no. 6 (September 1, 1994): 271–79. http://dx.doi.org/10.2166/wst.1994.0278.

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By combining a sequential P-extraction with batch experiments the presented investigations clarify the mechanisms of (enhanced) biological phosphate elimination and especially to answer the following questions: are any physicochemical mechanisms involved in the biological phosphate elimination? are there any interactions between biological and physicochemical unit operations? If so, are these of synergistic or antagonistic nature? The following main results were found: Results of batch experiments: – calcium decreases under anaerobic conditions; this indicates Ca-P-precipitation. – magnesium increases under anaerobic conditions and decreases under aerobic conditions just as phosphate does; there is a high correlation between dissolved magnesium and dissolved phosphorus. Therefore magnesium seems to participate in biological mechanisms (counter-ion of polyphosphates). – concerning the total P elimination efficiency both unit processes seem to have a synergistic effect (biologically mediated P-precipitation). Results of P-fractionations: – there is a certain amount of particulate physicochemically bound phosphorus, which should not be neglected. – although the biologically bound phosphorus dominates (as a rule), this amount depends on the concentration of the readily biodegradable COD significantly. – during the cyclic P-release/P-uptake not only transitions from soluble phase to particulate phase but alsotransfers within the particulate phase take place. – the total P-content of the activated sludge and the sum of the Non Reactive Phosphorus-fractions (without Phase Separation-Non Reactive Phosphorus) seem to be suitable to characterize the capacity of the biological phosphate elimination. Conclusions: Physicochemical mechanisms take part in the enhanced biological phosphate removal and they should be taken into consideration. Therefore they should be included into the deterministic model development.

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Whitson, I. R., S. Abboud, E. E. Prepas, and D. S. Chanasyk. "Trends in dissolved phosphorus in Gray Luvisol soil profiles after forest harvest." Canadian Journal of Soil Science 85, no. 1 (February 1, 2005): 89–101. http://dx.doi.org/10.4141/s04-030.

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Forest disturbances that increase P export from hillslopes will have negative consequences for site productivity and regional water quality. We studied P behavior in Gray Luvisols to understand the soil profile’s influence on P export from typical hillslopes of the Boreal Plain ecozone. We hypothesized that (1) P concentration is highest in upper horizons, (2) solution P is primarily in the dissolved and organic form, and (3) forest harvest will increase solution P concentration. We analyzed the soil solution, with emphasis on P, and determined P sorption properties of key soil horizons. Mean soluble reactive phosphorus concentration decreased with depth, ranging from 64 mg L-1 in the forest floor to 0.01 mg L-1 in the groundwater zone; solution P was mostly orthophosphate. Water soluble phosphorus decreased from 74 ± 9 to 41 ± 9 mg L-1 and extractable phosphorus was reduced in the forest floor only on two of four sampling occasions after harvest. Dissolved organic carbon may indirectly promote orthophosphate dominance in solution by complexing metal cations that would otherwise precipitate metal-P from solution. Gray Luvisols probably export P to soils lower on the hillslope catena, such as those of the Gleysolic and Organic Orders, both commonly associated with wetlands. Key words: Forest soil, phosphorus, orthophosphate, Gray Luvisol, biogeochemistry, sorption

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Monbet, Phil, Ian D. McKelvie, and Paul J. Worsfold. "Phosphorus speciation, burial and regeneration in coastal lagoon sediments of the Gippsland Lakes (Victoria, Australia)." Environmental Chemistry 4, no. 5 (2007): 334. http://dx.doi.org/10.1071/en07049.

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Environmental context. Eutrophication can lead to the production of harmful algal blooms and is one of the world’s most serious water quality issues. Phosphorus is potentially the limiting macro-nutrient in fresh, estuarine and some marine waters. Consequently, it plays a crucial role in determining the ecological status of many aquatic ecosystems. Considerable effort has been invested in monitoring dissolved reactive phosphorus and total phosphorus in the water column, but less is known about the speciation of phosphorus, particularly in the sediment. This compartment is an important and dynamic reservoir of phosphorus and a potential long-term source of phosphorus release to the water column by the sediment–water interface. This paper investigates the solid-phase speciation and reorganisation of phosphorus within the sediments of a shallow lake system in south-east Australia (the Gippsland Lakes) which suffers from recurring harmful algae blooms. Various strategies are proposed to determine the minimum realistic timescale required to deplete the sediment of labile and reactive phosphorus species. Abstract. Solid-phase phosphorus pools in the sediments of two shallow lakes (Wellington and Victoria) in the Gippsland Lakes coastal lagoon system of south-east Australia are discussed. Cores (20-cm depth) were taken in summer and winter in both lakes and a sequential extraction scheme (SEDEX) was used to profile the exchangeable P (Pex), iron oxide/hydroxide bound P (PFe), authigenic P (Pauth), detrital P (Pdet) and organic P (Porg). Pore-water (Ppw) dissolved reactive phosphorus concentration profiles were also measured. The dominant forms of P were PFe (up to 53%) and Porg (35–55%), with the PFe fraction playing a key role in the short-term retention of P in the sediment. Benthic phosphorus fluxes at the sediment–water interface (μmol m–2 d–1) were determined from the sequential extraction data. The results were compared with flux measurements from the complementary approaches of benthic chamber experiments and Fickian diffusion calculations, to allow an insight into the nature and seasonal variations of the fluxes. The burial flux of phosphorus was also estimated from excess 210Pb profiles in the sediment of the lakes. All of these data were used to produce a phosphorus budget for the Gippsland Lakes which suggested that the sediment represents a substantial source of phosphorus within the lakes and thus clearly highlights the importance of the sedimentary compartment in shallow eutrophic ecosystems. Minimum realistic timescales for complete labile phosphorus depletion from the sediment (assuming no resupply from the sediment–water interface) were calculated and ranged from 8 to 22 years.

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32

Sato, M., R. Sakuraba, and F. Hashihama. "Phosphate monoesterase and diesterase activities in the North and South Pacific Ocean." Biogeosciences Discussions 10, no. 6 (June 20, 2013): 10095–124. http://dx.doi.org/10.5194/bgd-10-10095-2013.

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Abstract. To reveal the biogeochemical cycling of phosphorus in the Pacific Ocean, phosphate monoesterase and diesterase activities were measured with soluble reactive phosphorus (SRP) and labile and total dissolved organic phosphorus (DOP) concentrations in the North and South Pacific Ocean. Both esterase activities were noticeably enhanced around the western part of 30° N, where the surface SRP concentration was below 10 nM, while they showed no significant correlation with DOP concentration. The proportion of the activity in the dissolved fraction was higher for diesterase than monoesterase, which may support results from previous genomic analyses. Substrate affinity and the maximum hydrolysis rate of monoesterase were the highest at lower concentrations of SRP, showing the adaptation of microbes to inorganic phosphorus nutrient deficiency at the molecular level. The calculated turnover time of monoesters was 1 to 2 weeks in the western North Pacific Ocean, which was much shorter than the turnover time in other areas of the Pacific Ocean but longer than the turnover time in other phosphate-depleted areas. In contrast, the turnover rate of diesters was calculated to exceed 100 days, revealing that diesters in the western North Pacific were a biologically refractory phosphorus fraction. In future studies, a combination of molecular biological techniques and kinetic studies will reveal the entire process of biogeochemical cycling of phosphorus in the ocean, including components that were not elucidated in the present study.

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33

Zheng, Z. M., T. Q. Zhang, G. Wen, C. Kessel, C. S. Tan, I. P. O'Halloran, D. K. Reid, D. Nemeth, and D. Speranzini. "Soil Testing to Predict Dissolved Reactive Phosphorus Loss in Surface Runoff from Organic Soils." Soil Science Society of America Journal 78, no. 5 (August 29, 2014): 1786–96. http://dx.doi.org/10.2136/sssaj2014.02.0065.

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34

Daloğlu, Irem, Kyung Hwa Cho, and Donald Scavia. "Evaluating Causes of Trends in Long-Term Dissolved Reactive Phosphorus Loads to Lake Erie." Environmental Science & Technology 46, no. 19 (September 21, 2012): 10660–66. http://dx.doi.org/10.1021/es302315d.

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35

Lu, Shenglan, Hans Estrup Andersen, Hans Thodsen, Gitte Holton Rubæk, and Dennis Trolle. "Extended SWAT model for dissolved reactive phosphorus transport in tile-drained fields and catchments." Agricultural Water Management 175 (September 2016): 78–90. http://dx.doi.org/10.1016/j.agwat.2015.12.008.

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36

Auflitsch, Stefan, Darren M. W. Peat, Paul J. Worsfold, Stefan Auflitsch, and Ian D. McKelvie. "Determination of Dissolved Reactive Phosphorus in Estuarine Waters Using a Reversed Flow Injection Manifold†." Analyst 122, no. 12 (1997): 1477–80. http://dx.doi.org/10.1039/a705363k.

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37

Müller, Beat, Arno Stöckli, Ruth Stierli, Ernst Butscher, and René Gächter. "A low cost method to estimate dissolved reactive phosphorus loads of rivers and streams." J. Environ. Monit. 9, no. 1 (2007): 82–86. http://dx.doi.org/10.1039/b613153k.

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38

Liang, Tao, Yali Tong, Xiahui Wang, and Lingqing Wang. "Release of reactive phosphorus from sediments in Dongting Lake linked with the Yangtze River." Environmental Chemistry 14, no. 1 (2017): 48. http://dx.doi.org/10.1071/en16072.

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Environmental contextEutrophication caused by excessive inputs of phosphorus is a prevalent global environmental problem. Reactive phosphorus released from sediments was measured by two new in situ passive sampling techniques capable of high-resolution measurements of phosphorus concentration. The methods provide the scientific evidence for solving the problems associated with deteriorating surface water quality. AbstractInternal phosphorus (P) loading is regarded as a major eutrophication factor and may prevent improvements in lake water quality. Two new in situ passive sampling techniques, high-resolution pore-water equilibrators (HR-Peeper) and zirconium oxide-based diffusive gradients in thin films (Zr-oxide DGT), were combined to measure dissolved reactive phosphorus (DRP) (CPeeper) and labile phosphorus (CDGT) at five sites in South Dongting and West Dongting Lakes. The vertical distribution of CPeeper and CDGT displayed similarity, which demonstrated that the buffering capacity of the labile P in sediments was similar at different depths. The diffusion flux of P from the sediments at the sediment–water interface ranged from 1.9 to 88ng m–2 day–1, with an average value of 38ng m–2 day–1. The P flux at the entrances to the Yuan, Li and Zi Rivers was fairly large at all five sites. The sediments at the five sites released P into overlying water, indicating that the sediments are an important source of P for Dongting Lake.

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39

Nolan, AL, GA Lawrance, and M. Maeder. "Phosphorus speciation in the Williams River, New South Wales: Eutrophication and a chemometric analysis of relationships with other water quality parameters." Marine and Freshwater Research 46, no. 7 (1995): 1055. http://dx.doi.org/10.1071/mf9951055.

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Phosphorus concentrations as both total phosphorus and partitioned (dissolved, 'bioavailable' and 'available-reactive') phosphorus have been determined in a quality-controlled study of the Williams River in the Hunter Valley, Australia, at Boags Hill during a five-month period. Complementary analyses of each sample for a range of standard water quality parameters were also obtained. Strong interrelationships between total phosphorus and partitioned phosphorus suggest that total phosphorus alone may be as adequate an indicator of potential algal growth as bioavailable phosphorus in this river system, an outcome supported by limited algal bioassay results. Principal component or factor analysis of the complete data set allowed qualitative insight into the relationship between the different concentrations (relevant cations and anions) and other measurements (colour (apparent), turbidity, etc.). Compounds from similar sources are clustered in the principal component plots. The samples taken over a specific time period have been analysed in a similar way, with clustering according to rainfall patterns being clearly indicated.

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40

Ding, Shiming, Qin Sun, Di Xu, Fei Jia, Xiang He, and Chaosheng Zhang. "High-Resolution Simultaneous Measurements of Dissolved Reactive Phosphorus and Dissolved Sulfide: The First Observation of Their Simultaneous Release in Sediments." Environmental Science & Technology 46, no. 15 (July 13, 2012): 8297–304. http://dx.doi.org/10.1021/es301134h.

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41

Wells, Daniel E., Jeffrey S. Beasley, Edward W. Bush, and Lewis A. Gaston. "Poultry Litter Ash Rate and Placement Affect Phosphorus Dissolution in a Horticultural Substrate1." Journal of Environmental Horticulture 35, no. 3 (September 1, 2017): 117–27. http://dx.doi.org/10.24266/0738-2898-35.3.117.

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Abstract Poultry litter ash (PLA) is a byproduct of bioenergy production and an effective P source for horticultural crops since it reduces P losses from container production due to its low P solubility. Experiments were conducted to determine effects of rate and placement of PLA on P loss from greenhouse crop production and growth and quality of two commonly-grown greenhouse crops, Verbena canadensis Britton ‘Homestead Purple' and Lantana camara L. ‘New Gold', by comparing two rates (140 and 280 g·m−3 P or 0.4 and 0.8 lb·yd−3) and two application methods (post-plant topdressed and pre-plant incorporated). Leachate-dissolved reactive phosphorus (DRP) concentrations were reduced by an average of 24% as P rate was reduced from 280 to 140 g·m−3, but were 134% less on average when PLA was topdressed instead of incorporated. Foliar P concentrations were less 33% and 44% for verbena and lantana, respectively when plants were topdressed compared to incorporated. Shoot biomass of verbena and lantana was 9% and 24% greater, respectively, when incorporating instead of topdressing PLA. As a P source, PLA should be pre-plant incorporated within the substrate at a total P rate between 140 g·m−3 (0.4 lb·yd−3) and 280 g·m−3 (0.8 lb·yd−3). Index words: phosphorus, poultry litter ash, Verbena canadensis Britton ‘Homestead Purple', Lantana camara L. ‘New Gold', dissolved reactive phosphorus. Species used in this study: ‘Homestead Purple' verbena (Verbena canadensis Britton); ‘New Gold' lantana (Lantana camara L.).

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42

Sato, M., R. Sakuraba, and F. Hashihama. "Phosphate monoesterase and diesterase activities in the North and South Pacific Ocean." Biogeosciences 10, no. 11 (November 27, 2013): 7677–88. http://dx.doi.org/10.5194/bg-10-7677-2013.

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Abstract. Phosphate monoesterase and diesterase activities were measured with soluble reactive phosphorus (SRP) and labile and total dissolved organic phosphorus (DOP) concentrations in the North and South Pacific Ocean, to reveal the microbial utilization of phosphate esters in the Pacific Ocean. Both esterase activities were noticeably enhanced around the western part of 30° N, where the surface SRP concentration was below 10 nM, while they showed no significant correlation with DOP concentration. The proportion of the activity in the dissolved fraction was higher for diesterase than monoesterase, which may support results from previous genomic analyses. Substrate affinity and the maximum hydrolysis rate of monoesterase were the highest at lower concentrations of SRP, showing the adaptation of microbes to inorganic phosphorus nutrient deficiency at the molecular level. The calculated turnover time of monoesters was 1 to 2 weeks in the western North Pacific Ocean, which was much shorter than the turnover time in other areas of the Pacific Ocean but longer than the turnover time in other phosphate-depleted areas. In contrast, the turnover rate of diesters was calculated to exceed 100 days, revealing that diesters in the western North Pacific were a biologically refractory phosphorus fraction. In the present study, it was revealed that both phosphate monoesters and diesters can be a phosphorus source for microbes in the phosphate-depleted waters, although the dynamics of the two esters are totally different.

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43

Kulbat, Eliza, and Krzysztof Czerwionka. "Influence of Phosphorus Speciation on Its Chemical Removal from Reject Water from Dewatering of Municipal Sewage Sludge." Energies 16, no. 3 (January 24, 2023): 1260. http://dx.doi.org/10.3390/en16031260.

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The aim of the presented research was the assessment of phosphorus speciation impact on the precipitation of phosphorus in reject water using Ca(OH)2. To achieve this, phosphorus speciation (organic and inorganic phosphorus in suspension and in dissolved form) in reject water that is produced during sludge dewatering, after methane digestion in wastewater treatment plants (WWTPs), was determined. This study covered the materials from four WWTPs with different compositions of feedstock for anaerobic digestion (AnD). In one, the AnD process of primary and secondary sludge was carried out without co-substrate, while in three others, co-substrate (waste from the agri-food industry and external waste-activated sludge and fats from industrial plants) was examined. The investigation was conducted in batch reactors using doses of Ca(OH)2 ranging from 2500 to 5500 mg Ca/dm3. The percentage of phosphorus forms determined in the raw reject water was similar, with the dominant form being soluble reactive phosphorus (SPR) (percentage from 87 to 96%). The small differences observed were dependent on the composition of the AnD feedstock. The results showed that, in all analysed wastewater, very high (exceeding 99.9%) phosphate phosphorus removal efficiencies were obtained using Ca(OH)2 for short reaction times (t = 1 h). The efficiency of phosphate removal depended on pH but not on the forms of phosphorus in the analysed reject water.

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44

Vincent, Gilles. "Artificial Marshes to Maintain Water Quality: The Beach of Ile Notre-Dame, Montréal." Water Quality Research Journal 27, no. 2 (May 1, 1992): 327–40. http://dx.doi.org/10.2166/wqrj.1992.023.

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Abstract In June 1990, the City of Montréal opened a beach on an artificial lake in the southern sector of Ile Notre-Dame in the Saint Lawrence River, a man-made island built for Expo ’67. This lake is fed from the Saint Lawrence River and the beach stretches some 600m with a swimming area of approximately 15 000 m2. Since the desired environmental character was that of a natural lake, it was decided to avoid the use of conventional methods of water purification such as treatment with chlorine. Instead, a series of techniques more compatible with natural systems were chosen in order to maintain water quality. The major component of these techniques is a “filter-lake” complex. Occupying an area of 20 000 m2, the “filter-lake” complex consists of four ponds of varying depth where more than 100 000 aquatic plants of different native species were introduced. Intake pipes draw 28 litres/second of water into the first pond and then, water circulates by gravity through the three remaining ponds. During the last two seasons, several parameters were monitored in order to evaluate the efficiency of the system. The parameters considered were: soluble reactive phosphorous, total phosphorus, dissolved phosphorus, nitrates, ammonium, suspended solids and faecal coliforms. Preliminary results indicate that the system of artificial wetlands used at the beach of Ile Notre-Dame is efficient in water purification. The ponds are very good traps for soluble reactive phosphorus and nitrates. A good interception is also observed in the second pond for total phosphorus and suspended solids. Faecal coliforms removal however seems uncertain and long-term effectiveness is questionnable.

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45

Hauer, FR, and CN Spencer. "Phosphorus and Nitrogen Dynamics in Streams Associated With Wildfire: a Study of Immediate and Longterm Effects." International Journal of Wildland Fire 8, no. 4 (1998): 183. http://dx.doi.org/10.1071/wf9980183.

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Stream nutrient data were collected both during a wildfire and over a subsequent five-year period. Sampling was from a series of paired watersheds located within and outside of the wildfire. Phosphorus and nitrogen concentrations increased from 5 to 60 fold over background levels during the first few days of the month-long wildfire with maximum recorded concentrations as high as 135 μg/L soluble reactive phosphorus, 261 μg/L ammonium, and 61 μg/L nitrate. Total phosphorus and total nitrogen during this same time period increased up to 206 μg/L and 349 mμg/L, respectively. Nutrient concentrations declined to background levels (<5-10 μg/L) within a few weeks after the fire. Over the following five years we observed dissolved nutrient concentrations reaching >40 μg/L soluble reactive phosphorus and >125 μg/L nitrate in impacted streams, concentrations >5 fold over those observed in control streams. In high gradient watersheds, all nutrients were easily transported to the streams with most notable impact during the early years after the fire. In less steep terrain, soluble reactive phosphorus concentrations were significantly higher 3 to 5 years after the fire, which also corresponded to relatively high spring hydrographs. In contrast, nitrogen compounds were observed to be significantly higher in concentration in fire impact streams in the years immediately following the fire. We attribute these differences in the rate of nutrient loads to be the result of the different mobilization mechanisms of phosphorus and nitrogen and the different soil and geomorphic settings of the watersheds drained by the different streams.

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46

Datry, Thibault, and Scott T. Larned. "River flow controls ecological processes and invertebrate assemblages in subsurface flowpaths of an ephemeral river reach." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 8 (August 2008): 1532–44. http://dx.doi.org/10.1139/f08-075.

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We present the first measurements of solutes, invertebrates, and microbial activity in the semi-perched hyporheic, parafluvial, and riparian flowpaths of an ephemeral river channel. Dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) concentrations decreased as water from an adjacent river mainstem moved through the flowpaths. DOC, DON, and DOP processing rates decreased with increasing mainstem flow and increased with parafluvial zone length. These patterns suggest that the surface water zones of perched river systems are organic nutrient sources to subsurface flowpaths and that parafluvial zones of these systems are strong sinks for organic matter. No longitudinal changes were detected in NO3–concentrations, and relationships between NO3–processing and hydrological variables were not significant. NO3–concentrations were uniformly high, and microbial activity and DOC and dissolved reactive phosphorus (DRP) concentrations were low, suggesting that biological NO3–removal was carbon- or phosphorus-limited. Invertebrate assemblages also varied between subsurface zones: density and taxon richness in the hyporheic and parafluvial zones were higher than in the riparian zone, and evenness was higher in the riparian zone than in the hyporheic or parafluvial zones. Distinct invertebrate assemblages in riparian zones may reflect greater hydrologic stability compared with hyporheic and parafluvial zones.

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47

Duan, Shuiwang, Thomas S. Bianchi, Peter H. Santschi, and Rainer M. W. Amon. "Effects of tributary inputs on nutrient export from the Mississippi and Atchafalaya Rivers to the Gulf of Mexico." Marine and Freshwater Research 61, no. 9 (2010): 1029. http://dx.doi.org/10.1071/mf09235.

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In order to better understand the seasonal patterns of nutrient loadings from the Mississippi River to the Gulf of Mexico, nutrient mass balance analyses were performed for the Mississippi River system to separate the effects of primary tributary inputs from in-channel processes. Our results showed that seasonal changes in dissolved inorganic nutrients resulted from conservative mixing of primary tributaries. Maximal values of nitrate plus nitrite (NO3+2) and soluble reactive phosphorus (SRP) fluxes during May through July were largely attributed to inputs from the upper Mississippi River (UMR), which was highest in NO3+2 and SRP levels and contributed more water during this period. Mass balances also showed net losses of particulate nitrogen and phosphorus (29% and 18%, respectively), with the highest values occurring during the falling stage. We speculate that one possible reason was retention of coarse suspended sediments that were mainly derived from the Missouri River. The loss of dissolved organic nitrogen and phosphorus was also apparent (∼12% and 20%, respectively), and the largest loss occurred during summer. This study highlights the importance of divergent processes in controlling different forms of nutrients in large rivers.

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48

Lucci, G. M., R. W. McDowell, and L. M. Condron. "Phosphorus source areas in a dairy catchment in Otago, New Zealand." Soil Research 50, no. 2 (2012): 145. http://dx.doi.org/10.1071/sr12030.

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It is important to recognise source areas of phosphorus (P) in agricultural catchments and to understand how they contribute to catchment losses of P in order to effectively target mitigation strategies to decrease losses to surface waters. In a small dairy catchment (4.1 ha), soil physical properties and overland flow from pasture, a laneway, and around a watering trough were measured, together with subsurface flows from pasture and catchment discharge. Soil measured around the trough and in the laneway was found to be enriched in Olsen P (56 and 201 mg P/kg, respectively) compared with the pasture (24 mg P/kg), as well as having a greater bulk density resulting from more frequent use by animals. Dissolved P losses from lane and trough plots were greatly enhanced via dung. At the catchment scale, sources and transport processes resulted in losses mainly in the particulate P form (0.21 mg/L), while dissolved reactive P (DRP) concentrations were enriched during storm events (0.08 mg/L). Subsurface flow was found to be an important contributor of discharge and likely P losses, and this warrants further investigation. The scaling up of overland-flow plot data suggested that the laneway contributed up to 89% of the DRP load when surface overland flow was likely. This represents a substantial source of P loss on dairy farms. Additionally, the variation of sources and transport processes with season adds another aspect to the critical source area concept, and suggests that given the loss during summer and high algal availability of dissolved P, mitigation strategies should target decreasing dissolved P loss from the laneway.

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Bowszys, Magdalena, Renata Tandyrak, Iwona Gołaś, and Ewa Paturej. "Zooplankton communities in a river downstream from a lake restored with hypolimnetic withdrawal." Knowledge & Management of Aquatic Ecosystems, no. 421 (2020): 12. http://dx.doi.org/10.1051/kmae/2020005.

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Restoring lakes with hypolimnetic withdrawal can severely threaten water quality and biocenosis downstream. The objective of this study was to evaluate the effect of lake restoration on riverine zooplankton during a period of intense hypolimnion water inflow. Zooplankton density and biomass were determined in water samples. The water samples were also analyzed to determine the following physicochemical parameters: flow rate, dissolved oxygen, hydrogen sulphide, sulphate, ammonium nitrogen, nitrate nitrogen, total phosphorous, soluble reactive phosphorus, total organic carbon, and temperature. The results of multiple regression indicated that water flow was the most significant variable and was the best predictor of total zooplankton and rotifer density. Soluble reactive phosphorous was the main predictor of copepod biomass and density. Our study showed that hypolimnetic withdrawal disturbed the natural process of planktic community transformation, which was linked to the environmental shift from lacustrine to riverine. During the study, zooplankton density and biomass were low, but not as low as when the pipeline was operating at maximum output. At present, this lake restoration method has become more sustainable, because the adverse effects of hypolimnetic withdrawal on the recipient river have been minimized and limited to several weeks.

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Ahmad, Zahoor, Mohamed A. M. Abd-Elbasit, Mitsuhiro Inoue, Hiroshi Yasuda, Toshimasa Honna, and Sadahiro Yamamoto. "Use of Two Industrial Wastes as Soil Amendments: Effect on Dissolved Reactive Phosphorus in Runoff." Soil and Sediment Contamination: An International Journal 21, no. 2 (February 2012): 207–26. http://dx.doi.org/10.1080/15320383.2012.649376.

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Journal articles on the topic 'Dissolved reactive phosphorus'

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