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.

scholarly journals Contrasting glacial meltwater effects on post-bloom phytoplankton on temporal and spatial scales in Kongsfjorden, Spitsbergen

Elem Sci Anth ◽  
2018 ◽  
Vol 6 ◽  
Author(s):  
Willem H. van de Poll ◽  
Gemma Kulk ◽  
Patrick D. Rozema ◽  
Corina P. D. Brussaard ◽  
Ronald J. W. Visser ◽  
...  
Keyword(s):  
Nutrient Limitation ◽  
Water Column ◽  
Chlorophyll A ◽  
Carbon Fixation ◽  
Spatial Scales ◽  
Nutrient Concentrations ◽  
Fixation Rate ◽  
Glacial Meltwater ◽  
Chl A ◽  
N Limitation

Glacial meltwater discharge in fjords on the west coast of Spitsbergen is increasing due to climate change. The influence of this discharge on phytoplankton nutrient limitation, composition, productivity and photophysiology was investigated in central (M) and inner (G) Kongsfjorden (79°N, 11°40’E). Freshwater influx intensified stratification during June 2015, coinciding with surface nutrient depletion. Surface nutrient concentrations were negatively correlated with stratification strength at station M. Here, nitrate addition assays revealed increasing N limitation of surface phytoplankton during the second half of June, which was followed by a pronounced compositional change within the flagellate-dominated phytoplankton community as dictyochophytes (85% of chl a) were replaced with smaller haptophytes (up to 60% of chlorophyll a) and prasinophytes (20% of chlorophyll a). These changes were less pronounced at station G, where surface phosphate, ammonium and nitrate concentrations were occasionally higher, and correlated with wind direction, suggesting wind-mediated transport of nutrient-enriched waters to this inner location. Therefore, glacial meltwater discharge mediated nutrient enrichment in the inner fjord, and enhanced stratification in inner and central Kongsfjorden. Surface chlorophyll a and water column productivity showed 3–4-fold variability, and did not correlate with nutrient limitation, euphotic zone depth, or changed taxonomic composition. However, the maximum carbon fixation rate and photosynthetic efficiency showed weak positive correlations to prasinophyte, cryptophyte, and haptophyte chlorophyll a. The present study documented relationships between stratification, N limitation, and changed phytoplankton composition, but surface chlorophyll a concentration, phytoplankton photosynthetic characteristics, and water column productivity in Kongsfjorden appeared to be driven by mechanisms other than N limitation.

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