scholarly journals Comment on "Solute-specific scaling of inorganic nitrogen and phosphorus uptake in streams" by Hall et al. (2013)

2015 ◽  
Vol 12 (18) ◽  
pp. 5365-5369 ◽  
Author(s):  
R. González-Pinzón ◽  
J. Mortensen ◽  
D. Van Horn
Keyword(s):  
Nutrient Uptake ◽  
Inorganic Nitrogen ◽  
Phosphorus Uptake ◽  
River Continuum ◽  
Nitrogen And Phosphorus ◽  
Scaling Method ◽  
Nutrient Demand ◽  
Specific Discharge ◽  
Nitrogen And Phosphorus Uptake ◽  
Tracer Experiments

Abstract. Hall et al. (2013) presented a synthesis on 969 nutrient tracer experiments conducted primarily in headwater streams (generally < fourth-order streams), with discharges < 200 L s−1 for ~90 % of the experiments, and used a scaling method to test the hypothesis that nutrient demand is constant with increasing stream size (i.e., along a river continuum). In this comment we present a reanalysis of a subset of the data used by Hall et al. (2013) and propose that their correlations between nutrient uptake lengths of ecologically important solutes and specific discharge are inadvertently spurious. Therefore, the conclusions derived from such correlations are debatable. We conclude the comment by highlighting some of the uncertainties associated with using modeling frameworks for scaling nutrient uptake in stream ecosystems.

scholarly journals Method of biochar application affects growth, yield and nutrient uptake of cowpea

2020 ◽  
Vol 5 (1) ◽  
pp. 352-360
Author(s):  
Edward Yeboah ◽  
Gideon Asamoah ◽  
Patrick Ofori ◽  
Ben Amoah ◽  
Kwaku Osei Adu Agyeman
Keyword(s):  
Nutrient Uptake ◽  
Block Design ◽  
Phosphorus Uptake ◽  
Growth Yield ◽  
Growth And Yield ◽  
Shoot Biomass ◽  
Nitrogen And Phosphorus ◽  
Yield Data ◽  
Nitrogen And Phosphorus Uptake ◽  
Methods Of Application

AbstractBiochar produced from pyrolysis of organic materials has been found to improve plant growth by improving the physical and chemical characteristics of the soil as well as enhancing the sequestration of carbon dioxide that would release into the atmosphere through the decomposition of organic residues. However, there is scanty information on the methods used to apply biochar in order to optimize the benefits of biochar use for agricultural production. In view of this, a field study was carried out at the experimental field of CSIR – Soil Research Institute, Kumasi, to assess the effect of method of biochar application on the growth, yield and nutrient uptake of cowpea (Vigna unguiculata) in a moderately acidic sandy Ferric Acrisol. The experiment was set up using a Randomized Complete Block Design with three replications. The treatments imposed were as follows: control, broadcasting, spot and ring methods of application. The parameters assessed included growth and yield data as well as nitrogen and phosphorus uptake in shoots and grains. The data collected were subjected to analysis of variance using Genstat 12th edition. The results showed that the spot and ring methods of application significantly enhanced height, girth, nodule number and dry weight, shoot biomass and grain yield as well as nitrogen and phosphorus contents in shoots and grains when compared with the broadcasting method and control. This study therefore recommends the spot and ring methods of biochar application for adoption in cowpea production for enhanced growth, yield and nitrogen and phosphorus uptake.

Summer-winter transitions in Antarctic ponds II: Biological responses

2011 ◽  
Vol 23 (3) ◽  
pp. 243-254 ◽  
Author(s):  
Ian Hawes ◽  
Karl Safi ◽  
Jenny Webster-Brown ◽  
Brian Sorrell ◽  
David Arscott
Keyword(s):  
Dissolved Oxygen ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Inorganic Nitrogen ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Molar Ratio ◽  
Nitrogen And Phosphorus ◽  
Freeze Concentration ◽  
Nitrogen And Phosphorus Uptake

AbstractWe observed ice formation and water column attributes in four shallow Antarctic ponds between January and 7 April 2008. During that time ponds went from ice-free to > 80 cm thick ice, near-freshwater to hypersaline, well-lit to near darkness and temperatures fell to below zero. Here we examine shifts in biological activity that accompanied these changes. During February, freeze-concentration and ongoing photosynthesis increased dissolved oxygen concentration to up to 100 mg l-1, with a near-equivalent decrease in dissolved inorganic carbon and a pH rise. Benthic photosynthesis was responsible for 99% of estimated biological oxygen production. Net oxygen accumulation ceased in late February, pH began to fall and inorganic carbon to increase, but the pool of dissolved oxygen was depleted only slowly. Anoxia had been attained in only one pond by April and there was little accumulation of indicators of anaerobic activity. The nitrogen and phosphorus balances of the ponds were dominated by organic forms, which, like DOC and CDOM, behaved conservatively. Conversely, inorganic nitrogen and phosphorus uptake was evident throughout the study period, at a molar ratio of 16N:1P in two of three ponds, consistent with uptake into biological material. We found no coupling between N and P uptake and photosynthesis.

scholarly journals Solute-specific scaling of inorganic nitrogen and phosphorus uptake in streams

2013 ◽  
Vol 10 (11) ◽  
pp. 7323-7331 ◽  
Author(s):  
R. O. Hall ◽  
M. A. Baker ◽  
E. J. Rosi-Marshall ◽  
J. L. Tank ◽  
J. D. Newbold
Keyword(s):  
Inorganic Nitrogen ◽  
N Uptake ◽  
Phosphorus Uptake ◽  
Soluble Reactive Phosphorus ◽  
Ammonium Uptake ◽  
Scaling Exponent ◽  
Nitrogen And Phosphorus ◽  
Uptake Length ◽  
Specific Discharge ◽  
Stream Size

Abstract. Stream ecosystem processes such as nutrient cycling may vary with stream position in the network. Using a scaling approach, we examined the relationship between stream size and nutrient uptake length, which represents the mean distance that a dissolved solute travels prior to removal from the water column. Ammonium (NH4+) uptake length increased proportionally with stream size measured as specific discharge (discharge/stream width) with a scaling exponent = 1.01. In contrast, uptake lengths for nitrate (NO3−) and soluble reactive phosphorus (SRP) increased more rapidly than increases in specific discharge (scaling exponents = 1.19 for NO3− and 1.35 for SRP). Additionally, the ratio of inorganic nitrogen (N) uptake length to SRP uptake length declined with stream size; there was relatively lower demand for SRP compared to N as stream size increased. Finally, we related the scaling of uptake length with specific discharge to that of stream length using Hack's law and downstream hydraulic geometry. Ammonium uptake length increased less than proportionally with distance from the headwaters, suggesting a strong role for larger streams and rivers in regulating nutrient transport.

scholarly journals Nitrogen and Phosphorus Uptake Dynamics in Tropical Cerrado Woodland Streams

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1080 ◽  
Author(s):  
Nícolas Reinaldo Finkler ◽  
Flavia Tromboni ◽  
Iola Boëchat ◽  
Björn Gücker ◽  
Davi Gasparini Fernandes Cunha
Keyword(s):  
Nutrient Uptake ◽  
N Uptake ◽  
Pollution Abatement ◽  
Phosphorus Uptake ◽  
Soluble Reactive Phosphorus ◽  
Nitrogen Retention ◽  
Water Velocity ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Lotic Ecosystem

Pollution abatement through phosphorus and nitrogen retention is a key ecosystem service provided by streams. Human activities have been changing in-stream nutrient concentrations, thereby altering lotic ecosystem functioning, especially in developing countries. We estimated nutrient uptake metrics (ambient uptake length, areal uptake rate, and uptake velocity) for nitrate (NO3–N), ammonium (NH4–N), and soluble reactive phosphorus (SRP) in four tropical Cerrado headwater streams during 2017, through whole-stream nutrient addition experiments. According to multiple regression models, ambient SRP concentration was an important explanatory variable of nutrient uptake. Further, best models included ambient NO3–N and water velocity (for NO3–N uptake metrics), dissolved oxygen (DO) and canopy cover (for NH4–N); and DO, discharge, water velocity, and temperature (for SRP). The best kinetic models describing nutrient uptake were efficiency-loss (R2 from 0.47–0.88) and first-order models (R2 from 0.60–0.85). NO3–N, NH4–N, and SRP uptake in these streams seemed coupled as a result of complex interactions of biotic P limitation, abiotic P cycling processes, and the preferential uptake of NH4–N among N-forms. Global change effects on these tropical streams, such as temperature increase and nutrient enrichment due to urban and agricultural expansion, may have adverse and partially unpredictable impacts on whole-stream nutrient processing.

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