The effect of nutrient concentrations and ratios on periphyton biomass in low conductivity streams: implications for determination of nutrient limitation

Inland Waters ◽  
2013 ◽  
Vol 3 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Mohamed Elsaholi ◽  
Mary Kelly-Quinn
Keyword(s):  
Nutrient Limitation ◽  
Nutrient Concentrations ◽  
Periphyton Biomass

scholarly journals Foliar Applications of Biostimulants Promote Growth, Yield and Fruit Quality of Strawberry Plants Grown under Nutrient Limitation

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 483 ◽  
Author(s):  
Sebastian Soppelsa ◽  
Markus Kelderer ◽  
Claudio Casera ◽  
Michele Bassi ◽  
Peter Robatscher ◽  
...  
Keyword(s):  
Nutrient Limitation ◽  
Fruit Quality ◽  
Growth Yield ◽  
Biomass Accumulation ◽  
Nutrient Concentrations ◽  
Negative Effects ◽  
Nutritional Conditions ◽  
Entire Duration ◽  
Single Fertilization

Biostimulants have been found effective in enhancing plant resistance toward stressful conditions. The aim of the present study was to evaluate the efficacy of selected biostimulants to overcome the negative effects of nutrient limitation on the growth performances and on the fruit quality of soilless cultivated strawberry plants. The condition of nutrient limitation was imposed by supplying the plants with only a single fertilization at transplantation and by excluding any further nutrient supply for the entire duration of the experiment (three months, from May to July). Strawberry plants were treated seven times during the period from preflowering up to berry maturation with different classes of biostimulants (humic acids, alfalfa hydrolysate, macroseaweed extract and microalga hydrolysate, amino acids alone or in combination with zinc, B-group vitamins, chitosan, and a commercial product containing silicon) at commercial dosages. The use of alfalfa hydrolysate, vitamins, chitosan, and silicon was able to promote biomass accumulation in roots (four to seven folds) and fruits (+20%) of treated plants, whereas the total leaf area increased by 15%–30%. Nutrient concentrations in leaves and roots showed variations for microelements (e.g., Fe, B, Zn, and Si) in response to biostimulant applications, whereas no significant differences were observed for macronutrient contents among treatments. Final berry yield was found around 20% higher in chitosan- and silicon-treated plants. Chitosan treatment significantly increased pulp firmness (by 20%), while a high nutritional value (e.g., phenolic compounds concentration) was observed in alfalfa- and seaweed-treated fruits (+18%–20% as compared to control). The overall outcomes of the present experiment show that selected biostimulants can be considered as a valid agronomic tool able to contrast the negative consequence of growing crops under insufficient nutritional conditions.

Nutrient concentrations in mire vegetation as a measure of nutrient limitation in mire ecosystems

1995 ◽  
Vol 6 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Martin J. Wassen ◽  
Harry G.M. Olde Venterink ◽  
Evalyne O.A.M. Swart
Keyword(s):  
Nutrient Limitation ◽  
Nutrient Concentrations ◽  
Mire Vegetation

scholarly journals Microbial nutrient limitation in arctic lakes in a permafrost landscape of southwest Greenland

2015 ◽  
Vol 12 (14) ◽  
pp. 11863-11890
Author(s):  
B. Burpee ◽  
J. E. Saros ◽  
R. M. Northington ◽  
K. S. Simon
Keyword(s):  
Nutrient Limitation ◽  
Enzyme Activities ◽  
Arctic Lakes ◽  
The Arctic ◽  
Nutrient Concentrations ◽  
Nutrient Inputs ◽  
P Limitation ◽  
Microbial P ◽  
Microbial Nutrient Limitation ◽  
Southwest Greenland

Abstract. Permafrost is degrading across regions of the Arctic, which can lead to increases in nutrient concentrations in surface freshwaters. The oligotrophic state of many arctic lakes suggests that enhanced nutrient inputs may have important effects on these systems, but little is known about microbial nutrient limitation patterns in these lakes. We investigated microbial extracellular enzyme activities (EEAs) to infer seasonal nutrient dynamics and limitation across 24 lakes in southwest Greenland during summer (June and July). From early to late summer, enzyme activities that indicate microbial carbon (C), nitrogen (N), and phosphorus (P) demand increased in both the epilimnia and hypolimnia by 74 % on average. Microbial investment in P acquisition was generally higher than that for N. Interactions among EEAs indicated that bacteria were primarily P limited. Dissolved organic matter (DOM, measured as dissolved organic carbon) was strongly and positively correlated with microbial P demand (R2 = 0.84 in July), while there were no relationships between DOM and microbial N demand. Microbial P limitation in June epilimnia (R2 = 0.67) and July hypolimnia (R2 = 0.57) increased with DOM concentration. The consistency of microbial P limitation from June to July was related to the amount of DOM present, with some low DOM lakes becoming N-limited in July. Our results suggest that future changes in P or DOM inputs to these lakes are likely to alter microbial nutrient limitation patterns.

In situ evidence for a nutrient limitation of phytoplankton growth in pelagic Antarctic waters

1994 ◽  
Vol 6 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Osmund Holm-Hansen ◽  
Anthony F. Amos ◽  
Nelson Silva S. ◽  
Virginia Villafañe ◽  
E. Walter Helbling
Keyword(s):  
Nutrient Limitation ◽  
Surface Waters ◽  
Phytoplankton Biomass ◽  
Drake Passage ◽  
Nutrient Concentrations ◽  
Ancillary Data ◽  
Water Types ◽  
Antarctic Waters ◽  
Subsurface Maximum

Studies in a large (30000 km2) sampling grid around Elephant Island, Antarctica, during January–March of four successive years (1990–1993) have shown that one of the water types within the sampling area (Drake Passage water) shows low chlorophyll a in surface waters and a subsurface maximum between 50 and 80 m depth. Ancillary data (beam attenuation, in situ chl a fluorescence) support the view that the extracted chl a values actually do represent increased phytoplankton biomass at depth; other data (oxygen concentrations and upwelling radiance at 683 nm) suggest that the phytoplankton within this subsurface maximum layer are photosynthetically active and do not represent a senescent, sinking population of cells. Such deep chl a maxima were found only in Drake Passage waters; in the other four water types sampled, chl a concentrations were maximal in surface waters and decreased with depth. Phytoplankton biomass and activity in Drake Passage waters is suggestive of a nutrient limitation for phytolankton growth in surface waters. Nutrient concentrations of N, P, and Si were high throughout the euphotic zone at all stations, and hence it is unlikely that any macronutrient would be limiting. The data presented in this paper support the hypothesis of Martin and colleagues that availability of Fe may limit phytoplankton biomass in pelagic Antarctic waters, but not in coastal waters where Fe concentrations are relatively high. All other reports on the effects of Fe on Antarctic phytoplankton have utilized deck incubations from which it is difficult to extrapolate such evidence of nutrient limitation to in situ conditions. Our data represent the first in situ evidence linking Fe limitation to the paradox of high macronutrient concentrations and low phytoplankton biomass in Antarctic pelagic waters.

Determination of some physicochemical parameteres and inorganic nutrient content of Gediz River (Manisa)

2015 ◽  
Vol 40 (3) ◽  
Author(s):  
Tuğba Şentürk ◽  
Şükran Yıldız
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Physicochemical Parameters ◽  
Nutrient Content ◽  
Nutrient Concentrations ◽  
Western Turkey ◽  
River Water Samples ◽  
Gediz River

AbstractObjective: This present investigation aimed at assessing the water quality of the Gediz River located in western Turkey.Methods: Some physicochemical parameters and nutrient concentrations of the surface water of Gediz River were determined over a period of twelve months (October to September 2012) at 5 sampling sites along the river.Results: Data on some ions namely NHConclusion: This indicates pollution of the river water samples from the areas studied. Our findings highlighted the deterioration of water quality of the river due to anthropogenic and agriculturel activities.

The Dynamic Vegetation Model HUMBOLDT (LSMbio) The role of biodiversity and nutrient limitation in driving ecosystem processes on a tropical altitudinal gradient

2020 ◽  
Author(s):  
Mateus Dantas de Paula ◽  
Thomas Hickler
Keyword(s):  
Nutrient Limitation ◽  
Altitudinal Gradient ◽  
Plant Traits ◽  
Full Range ◽  
Elevation Gradient ◽  
Nutrient Concentrations ◽  
Vegetation Model ◽  
Nitrogen And Phosphorus ◽  
Dynamic Vegetation Model ◽  
Trait Diversity

<p>The HUMBOLDT-LSM<sub>bio</sub> component is an expansion of the LPJ-GUESS dynamic vegetation model , including local diversity of plant traits and an organic matter module representing the Nitrogen and Phosphorus cycles. In the new trait variation module the initial full range of possible traits is filtered along the altitudinal gradient with the aim to predict the trait distribution of communities observed in the field. The model was parameterized using local trait data per species collected by field campaigns along the whole altitudinal gradient, considering the leaf and wood economics spectrum and tissue nutrient concentrations, and locally measured N and P flux data, in which we were able to use deposition and weathering rates, as well as soil organic and mineral layer nutrient concentrations. In order to evaluate the model with regards to nutrient limitation, the simulation experiment was designed with the NUMEX nutrient manipulation experiment in mind, meaning that the reference nutrient limited community was compared to simulations in which N or/and P limitations were deactivated (i.e. plants could grow independent of their N or P demands being met). Results in NUMEX suggested that the removal of nutrient limitation would produce more biotically homogenous communites, and taller trees with higher productivity and more allocation to belowground biomass.</p><p>Our results indicate that including trait diversity and nutrient limitation provide a significant improvement in relation to ecosystem representation especially at higher elevations. Deactivation of nutrient limitation suggests reduced community trait differentiation along the elevation gradient (e.g. specific leaf area), and increased productivity (i.e. Carbon and NPP values). Deactivation of trait diversity impels plant survival at higher altitudes. Significant model improvements are expected in the future with further field trait measurements from the RESPECT subprojects, and the inclusion of other significant processes such as leaf herbivory, seed dispersal and of course the coupled model runs with LSM<sub>atmo</sub> and LSM<sub>hydro</sub>.</p>

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