scholarly journals Downregulation of net phosphorus-uptake capacity is inversely related to leaf phosphorus-resorption proficiency in four species from a phosphorus-impoverished environment

2013 ◽  
Vol 111 (3) ◽  
pp. 445-454 ◽  
Author(s):  
Mariana C. R. de Campos ◽  
Stuart J. Pearse ◽  
Rafael S. Oliveira ◽  
Hans Lambers
Keyword(s):  
Phosphorus Uptake ◽  
Uptake Capacity ◽  
Resorption Proficiency ◽  
Impoverished Environment

Phosphorus dynamics in Australian lowland rivers

2001 ◽  
Vol 52 (1) ◽  
pp. 127 ◽  
Author(s):  
Ian T. Webster ◽  
Phillip W. Ford ◽  
Gary Hancock
Keyword(s):  
Water Column ◽  
Time Scale ◽  
Molecular Diffusion ◽  
Phosphorus Uptake ◽  
Transport Processes ◽  
Phosphorus Concentration ◽  
Uptake Capacity ◽  
Treated Sewage ◽  
Uptake Rates ◽  
Adsorption Desorption

In freshwater systems, phosphorus is adsorbed predominantly to clay within the sediments. Assuming a linear adsorption/desorption isotherm, rapid equilibrium adsorption, and transport by molecular diffusion, estimates are derived for (a) the rates of exchange between the adsorbed phosphorus pool in the sediments and the dissolved pool in the water column and (b) time scales to re-establish equilibrium after a step change in the water column phosphorus concentration. For oxic sediments, the time scale is of the order of tens of days. Anoxic release is much faster;the time scale is tens of minutes. The release of treated sewage at Narrabri abruptly raises the phosphorus concentration in the Namoi River. The concentration only returns to its original level 10–20 km downstream. A sediment adsorptive-uptake model underestimates the downstream phosphorus uptake rates. An alternative model, based on biotic uptake by Cladophora , describes reality better. It treats phosphorus transfer as controlled by physical transport processes and by the phosphorus uptake capacity of the biota. We show also that carp resuspension is faster than diffusion (6 v. 28 days) in restoring phosphorus concentrations in the water column after perturbation by rapid algal drawdown.

Biofilm phosphorus uptake capacity as a tool for the assessment of pollutant effects in river ecosystems

Ecotoxicology ◽  
2017 ◽  
Vol 26 (2) ◽  
pp. 271-282 ◽  
Author(s):  
Lorenzo Proia ◽  
Anna Romaní ◽  
Sergi Sabater
Keyword(s):  
Phosphorus Uptake ◽  
Uptake Capacity ◽  
River Ecosystems

scholarly journals Priming of leaf litter decomposition by algae seems of minor importance in natural streams during autumn

2018 ◽  
Author(s):  
Arturo Elosegi ◽  
Angie Nicolás ◽  
John S. Richardson
Keyword(s):  
Litter Decomposition ◽  
Nutritional Quality ◽  
Phosphorus Uptake ◽  
Canopy Cover ◽  
Minor Importance ◽  
Uptake Capacity ◽  
Microbial Decomposition ◽  
Natural Streams ◽  
Agricultural Streams ◽  
Closed Canopy

AbstractAllochthonous detritus from terrestrial origin is one of the main energy sources in forested headwater streams, but its poor nutritional quality makes it difficult to use by heterotrophs. It has been suggested that algae growing on this detritus can enhance its nutritional quality and promote decomposition. So far, most evidence of this “priming” effect is derived from laboratory or mesocosm experiments, and it is unclear what its importance is under natural conditions. We measured accrual of algae, phosphorus uptake capacity, and decomposition of poplar leaves in autumn in open- and closed-canopy reaches in 3 forest and 3 agricultural streams. Chlorophyll a abundance did not change significantly neither with stream type nor with canopy cover, although some between open and closed reaches, although in some agricultural streams it was higher in open than in closed canopy reaches. Canopy cover did not affect either phosphate uptake capacity or microbial decomposition. On the other hand, although there was no effect of canopy cover on invertebrate fragmentation rate, a significant interaction between canopy cover and stream suggests priming occurs at least in some streams. Overall, the results point to a weak effect of algae on litter decomposition in natural streams during autumn.

Solvent-Free Powder Synthesis and MOF-CVD Thin Films of the Mesoporous Metal-Organic Framework MAF-6

2019 ◽  
Author(s):  
Timothée Stassin ◽  
Ivo Stassen ◽  
Joao Marreiros ◽  
Alexander John Cruz ◽  
Rhea Verbeke ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Metal Organic Framework ◽  
Chemical Vapor ◽  
Uptake Capacity ◽  
Powder Synthesis ◽  
Crystalline Films ◽  
Metal Organic ◽  
Mesoporous Metal ◽  
First Time ◽  
Organic Framework

A simple solvent- and catalyst-free method is presented for the synthesis of the mesoporous metal-organic framework (MOF) MAF-6 (RHO-Zn(eIm)2) based on the reaction of ZnO with 2-ethylimidazole vapor at temperatures ≤ 100 °C. By translating this method to a chemical vapor deposition (CVD) protocol, mesoporous crystalline films could be deposited for the first time entirely from the vapor phase. A combination of PALS and Kr physisorption measurements confirmed the porosity of these MOF-CVD films and the size of the MAF-6 supercages (diam. ~2 nm), in close agreement with powder data and calculations. MAF-6 powders and films were further characterized by XRD, TGA, SEM, FTIR, PDF and EXAFS. The exceptional uptake capacity of the mesoporous MAF-6 in comparison to the microporous ZIF-8 is demonstrated by vapor-phase loading of a molecule larger than the ZIF-8 windows.

Sewage Treatment in Helophyte Beds–First Experiences with a New Treatment Procedure

1987 ◽  
Vol 19 (10) ◽  
pp. 1-10 ◽  
Author(s):  
K. Bucksteeg
Keyword(s):  
Waste Water ◽  
Rural Areas ◽  
Root Zone ◽  
Waste Water Treatment ◽  
Sewage Treatment ◽  
Uptake Capacity ◽  
Humid Climate ◽  
Climate Conditions ◽  
Trickling Filters ◽  
Operation Conditions

Waste water treatment in helophyte beds under humid climate conditions has been favoured by some German ecologists for some years. The idea is to cause waste water to flow horizontally through the root zone of helophytes to achieve satisfactory effluent properties. There exist many highly different proposals regarding the choice of soil and helophytes to be applied, bed area, design of inlets and outlets and operation conditions. A few plants have been operated in practice for some years. It appears that clogging is one of the main problems occurring in these plants. The hydraulic uptake capacity of soil is discussed in Darcy's law. Comparisons with observations of plants in operation are drawn. The interactions between soil properties, its uptake capacity, BOD5-, COD-, N- and P-reduction are evaluated. The effluent results of helophyte beds are compared with those of low-loaded trickling filters and of ponds used for sewage treatment in small villages in rural areas of Germany. It has been proved that the total construction costs of sewage treatment plants with helophyte beds used as the biological stage are higher when compared with those of conventional plants in general.

scholarly journals Synthesis of novel adsorbent based on tetrasulfide-functionalized fibrous silica KCC-1 for removal of Hg(II) cations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Azam Marjani ◽  
Reza Khan Mohammadi
Keyword(s):  
Effective Interaction ◽  
Sol Gel ◽  
Aqueous Media ◽  
Synthesis Method ◽  
Mercury Ions ◽  
Toxic Heavy Metals ◽  
Uptake Capacity ◽  
Hydrothermal Preparation ◽  
Ultrasonic Assisted ◽  
First Time

AbstractHg(II) has been identified to be one of the extremely toxic heavy metals because of its hazardous effects and this fact that it is even more hazardous to animals than other pollutants such as Ag, Au, Cd, Ni, Pb, Co, Cu, and Zn. Accordingly, for the first time, tetrasulfide-functionalized fibrous silica KCC-1 (TS-KCC-1) spheres were synthesized by a facile, conventional ultrasonic-assisted, sol–gel-hydrothermal preparation approach to adsorb Hg(II) from aqueous solution. Tetrasulfide groups (–S–S–S–S–) were chosen as binding sites due to the strong and effective interaction of mercury ions (Hg(II)) with sulfur atoms. Hg(II) uptake onto TS-KCC-1 in a batch system has been carried out. Isotherm and kinetic results showed a very agreed agreement with Langmuir and pseudo-first-order models, respectively, with a Langmuir maximum uptake capacity of 132.55 mg g–1 (volume of the solution = 20.0 mL; adsorbent dose = 5.0 mg; pH = 5.0; temperature: 198 K; contact time = 40 min; shaking speed = 180 rpm). TS-KCC-1was shown to be a promising functional nanoporous material for the uptake of Hg(II) cations from aqueous media. To the best of our knowledge, there has been no report on the uptake of toxic Hg(II) cations by tetrasulfide-functionalized KCC-1 prepared by a conventional ultrasonic-assisted sol–gel-hydrothermal synthesis method.

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