scholarly journals Investigating equations for measuring dissolved inorganic nutrient uptake in oligotrophic conditions

2020 ◽  
Author(s):  
Michael R. Stukel
Keyword(s):  
Nutrient Uptake ◽  
Ecosystem Model ◽  
Ammonium Uptake ◽  
Nutrient Concentrations ◽  
Nutrient Regeneration ◽  
Isotope Tracer ◽  
Uptake Rates ◽  
Label Incorporation ◽  
Moderate Complexity

ABSTRACTMultiple different equations have been used to quantify nutrient uptake rates from stable isotope tracer label incorporation experiments. Each of these equations implicitly assumes an underlying model for phytoplankton nutrient uptake behavior within the incubation bottle and/or pelagic environment. However, the applicability of different equations remains in question and uncertainty arising from subjective choices of which equation to use is never reported. In this study, I use two approaches to investigate the conditions under which different nutrient uptake equations should be used. First, I utilized a moderate-complexity pelagic ecosystem model that explicitly models the δ15N values of all model compartments (NEMURO+15N) to conduct simulated nitrate uptake and ammonium uptake incubations and quantify the accuracy of different nutrient uptake equations. Second, I used results of deckboard diel nutrient uptake experiments to quantify the biases of 24-h incubations relative to six consecutive 4-h incubations. Using both approaches, I found that equations that account for nutrient regeneration (i.e., isotope dilution) are more accurate than equations that do not, particularly when nutrient concentrations are low but uptake is relatively high. Furthermore, I find that if the goal is to estimate in situ uptake rates it is appropriate to use an in situ correction to standard equations. I also present complete equations for quantifying uncertainty in nutrient uptake experiments using each nutrient uptake equation and make all of these calculations available as Excel spreadsheets and Matlab scripts.

scholarly journals Technical Note: A comparison of two empirical approaches to estimate in-stream net nutrient uptake

2011 ◽  
Vol 8 (4) ◽  
pp. 875-882 ◽  
Author(s):  
D. von Schiller ◽  
S. Bernal ◽  
E. Martí
Keyword(s):  
Mass Balance ◽  
Nutrient Uptake ◽  
Nutrient Concentrations ◽  
Nutrient Loads ◽  
Data Set ◽  
Advantages And Disadvantages ◽  
Balance Approach ◽  
Uptake Rates ◽  
Empirical Approaches ◽  
Mass Balance Approach

Abstract. To establish the relevance of in-stream processes on nutrient export at catchment scale it is important to accurately estimate whole-reach net nutrient uptake rates that consider both uptake and release processes. Two empirical approaches have been used in the literature to estimate these rates: (a) the mass balance approach, which considers changes in ambient nutrient loads corrected by groundwater inputs between two stream locations separated by a certain distance, and (b) the spiralling approach, which is based on the patterns of longitudinal variation in ambient nutrient concentrations along a reach following the nutrient spiralling concept. In this study, we compared the estimates of in-stream net nutrient uptake rates of nitrate (NO3) and ammonium (NH4) and the associated uncertainty obtained with these two approaches at different ambient conditions using a data set of monthly samplings in two contrasting stream reaches during two hydrological years. Overall, the rates calculated with the mass balance approach tended to be higher than those calculated with the spiralling approach only at high ambient nitrogen (N) concentrations. Uncertainty associated with these estimates also differed between both approaches, especially for NH4 due to the general lack of significant longitudinal patterns in concentration. The advantages and disadvantages of each of the approaches are discussed.

Ammonia and Nitrate Uptake in the Lower Great Lakes

1980 ◽  
Vol 37 (9) ◽  
pp. 1365-1372 ◽  
Author(s):  
T. P. Murphy
Keyword(s):  
Great Lakes ◽  
Nitrate Uptake ◽  
Nutrient Concentrations ◽  
Short Term ◽  
Low Concentrations ◽  
Uptake Rates ◽  
Low K ◽  
Slow Turnover

Uptake of NH4+ is consistent with Michaelis–Menten kinetics in the Lower Great Lakes only if one assumes that the indophenol method of measuring NH4+ overestimates the in situ concentration. Short-term incubations were found necessary to avoid induction of nitrate uptake or changes in the rates of NH4+ uptake that occurred in long-term incubations. Uptake rates of nitrate are slow most of the summer. Since the nitrate is also present in low concentrations, most of the summer regeneration of nitrate must be very slow. The slow turnover of particulate N, low nutrient concentrations, slow rate of uptake relative to their ability to take up nitrogen, and the high affinity for ammonia (low Kt) suggest that in summer the primary productivity of the Lower Great Lakes is restricted by nitrogen deficiency.Key words: ammonia, nitrate, Lower Great Lakes

The role of plant uptake on the removal of organic matter and nutrients in subsurface flow constructed wetlands: a simulation study

2005 ◽  
Vol 51 (9) ◽  
pp. 213-223 ◽  
Author(s):  
G. Langergraber
Keyword(s):  
Organic Matter ◽  
Nutrient Uptake ◽  
Constructed Wetlands ◽  
Plant Uptake ◽  
Municipal Wastewater ◽  
Subsurface Flow ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Uptake Rates ◽  
Subsurface Flow Constructed Wetlands

Plants in constructed wetlands have several functions related to the treatment processes. It is generally agreed that nutrient uptake is a minor factor in constructed wetlands treating wastewater compared to the loadings applied. For low loaded systems plant uptake can contribute a significant amount to nutrient removal. The contribution of plant uptake is simulated for different qualities of water to be treated using the multi-component reactive transport module CW2D. CW2D is able to describe the biochemical elimination and transformation processes for organic matter, nitrogen and phosphorus in subsurface flow constructed wetlands. The model for plant uptake implemented describes nutrient uptake coupled to water uptake. Literature values are used to calculate potential water and nutrient uptake rates. For a constructed wetland treating municipal wastewater a potential nutrient uptake of about 1.9% of the influent nitrogen and phosphorus load can be expected. For lower loaded systems the potential uptake is significantly higher, e.g. 46% of the nitrogen load for treatment of greywater. The potential uptake rates could only be simulated for high loaded systems i.e. constructed wetlands treating wastewater. For low loaded systems the nutrient concentrations in the liquid phase were too low to simulate the potential uptake rates using the implemented model for plant uptake.

scholarly journals Technical Note: A comparison of two empirical approaches to estimate in-stream nutrient net uptake

2010 ◽  
Vol 7 (5) ◽  
pp. 7527-7542
Author(s):  
D. von Schiller ◽  
S. Bernal ◽  
E. Martí
Keyword(s):  
Mass Balance ◽  
Nutrient Uptake ◽  
Nutrient Concentrations ◽  
Nutrient Loads ◽  
Data Set ◽  
Advantages And Disadvantages ◽  
Balance Approach ◽  
Uptake Rates ◽  
Empirical Approaches ◽  
Mass Balance Approach

Abstract. To establish the relevance of in-stream processes on nutrient export at catchment scale it is important to accurately estimate whole-reach net nutrient uptake rates that consider both uptake and release processes. Two empirical approaches have been used in the literature to estimate these rates: (a) the mass balance approach, which considers changes in nutrient loads corrected by groundwater inputs between two stream locations separated by a certain distance, and (b) the spiralling approach, which is based on the patterns of longitudinal variation in ambient nutrient concentrations along a reach following the nutrient spiralling concept. In this study, we compared the estimates of in-stream net nutrient uptake rates of nitrogen (N) and the associated uncertainty obtained with these two approaches at different ambient conditions using a data set of monthly samplings in two contrasting stream reaches during two hydrological years. The rates calculated with the mass balance approach tended to be higher than those calculated with the spiralling approach but only at high ambient N concentrations. Uncertainty associated with these estimates also differed between both approaches, especially for ammonium due to the lack of significant longitudinal patterns in concentration. The advantages and disadvantages of each of the approaches are discussed.

Uptake of ammonium by four species of macroalgae in Port Phillip Bay, Victoria, Australia

1999 ◽  
Vol 50 (6) ◽  
pp. 515 ◽  
Author(s):  
Stuart J. Campbell
Keyword(s):  
Competitive Advantage ◽  
Nutrient Uptake ◽  
Uptake Rate ◽  
Undaria Pinnatifida ◽  
Ammonium Uptake ◽  
N Availability ◽  
Low Concentrations ◽  
Uptake Rates ◽  
Maximum Uptake Rate ◽  
Saturation Rate

The uptake rates of ammonium were determined for three species of native macroalgae and an exotic macroalga from Port Phillip Bay. All species exhibited rate-saturated mechanisms of uptake described by Michaelis–Menten uptake kinetics. At the highest concentration examined (28.6 µmol NH4-N) Hincksia sordida had a higher rate of uptake (435 µmol NH4 -N g dry wt–1 h–1) than Ulva sp. (108 µmol NH4-N g dry wt–1 h–1) or Polysiphonia decipiens (53 µmol NH4 -N g dry wt–1 h–1). Maximum surge uptake rate was highest for H. sordida and lowest for P. decipiens (802 and 57 µmol NH4 -N g dry wt–1 h–1 respectively). The introduced phaeophyte Undaria pinnatifida had an intermediate capacity for ammonium uptake which was dependent on blade maturity. Differences in the ratio of maximum uptake rate to half-saturation rate between surge and assimilation uptake phases suggest a propensity for some species to take up ammonium at low concentrations. The relationships between nutrient uptake and growth among species would afford mature U. pinnatifida, H. sordida and Ulva sp. a competitive advantage for ammonium uptake in winter during high N availability, whereas P. decipiens would be able to exploit low N concentrations in spring and summer.

scholarly journals Corn Grain and Stover Nutrient Uptake Responses from Sandy Soil Treated with Designer Biochars and Compost

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 942
Author(s):  
Jeffrey M. Novak ◽  
Donald W. Watts ◽  
Gilbert C. Sigua ◽  
Thomas F. Ducey
Keyword(s):  
Nutrient Uptake ◽  
Corn Stover ◽  
Pinus Contorta ◽  
Panicum Virgatum ◽  
Zea Mays L ◽  
Sandy Loam ◽  
Nutrient Concentrations ◽  
Extractable P ◽  
Soil Fertility Improvement ◽  
Corn Grain

Biochars are used for soil fertility improvement because they may contain certain elements that plants use as nutrients. However, few studies have demonstrated enhanced crop nutrient uptake. Our study examined nutrient uptake responses of corn (Zea Mays L.) grain and stover over 4 years (Y) after a Goldsboro sandy loam (fine-loamy, siliceous, sub-active, thermic Aquic Paleudults) received different designer biochars and a compost. The designer biochars were produced from lodgepole pine (Pinus contorta) chip (PC), poultry litter (PL), blends with switchgrass (SG; Panicum virgatum), and a SG compost alone. Topsoil treated with 100% PL biochar and blended PC:PL biochar had significantly greater Mehlich 1 (M1) extractable P, K and Na contents compared to the control or other treatments. No significant differences were detected in annual grain nutrient concentrations. In the first corn stover harvest (Y1), significantly greater concentrations of P and K were taken up after treatment with 100% PL biochar, with PC:PL blend and with SG when compared to control. By the fourth corn stover harvest (Y4), nutrient uptake between treatments was not significantly different. Biochar impact on corn stover P, K and Na concentrations was time dependent, suggesting that repeated biochar applications may be needed.

scholarly journals Uptake and translocation of nitrogen, phosphorus and calcium in soybean infected with Meloidogyne incognita and M. javanica

2002 ◽  
Vol 27 (2) ◽  
pp. 141-150 ◽  
Author(s):  
RUI G. CARNEIRO ◽  
PAULO MAZZAFERA ◽  
LUIZ CARLOS C.B. FERRAZ ◽  
TAKASHI MURAOKA ◽  
PAULO CESAR O. TRIVELIN
Keyword(s):  
Nutrient Uptake ◽  
Meloidogyne Incognita ◽  
Nutrient Concentrations ◽  
Tissue Mass ◽  
Split Root ◽  
Split Root System ◽  
Shoot Mass ◽  
Moderately Resistant ◽  
Nitrogen Phosphorus ◽  
Uptake And Transport

Two soybean (Glycine max) cultivars were used in this study, Ocepar 4, rated as moderately resistant to Meloidogyne incognita race 3 but susceptible to M. javanica, and 'BR 16', susceptible to both nematodes. The effect of nematodes infection on the uptake and transport of N, P and Ca to the shoot was studied in plants growing in a split root system. The upper half was inoculated with 0, 3,000, 9,000 or 27,000 eggs/plant while the lower half received 15N, 32P or 45Ca. Infected plants showed an increase of root but a decrease of shoot mass with increasing inoculum levels. In general, total endogenous nutrients increased in the roots and tended to decrease in the shoots with increasing inoculum levels. When concentrations were calculated, there was an increase in the three nutrients in the roots, and an increase of Ca but no significant variation of N and P was observed in the shoots. The total amount of 15N in the roots increased at the highest inoculum levels but 32P and 45Ca decreased. In the shoots there was a reduction of 32P and 45Ca. The specific concentrations of the labelled nutrients (abundance or radioactivity/tissue mass) also showed a decrease of 32P and 45Ca in the shoots and roots of infected plants and an increase of 15N in the shoots. Considering that overall nutrient concentrations reflect cumulative nutrient uptake and the data from labelled elements gave information at a specific moment of the infection, thus nematodes do interfere with nutrient uptake and translocation.

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.

scholarly journals Effect of incubation time and substrate concentration on N-uptake rates by phytoplankton in the Bay of Bengal

2005 ◽  
Vol 2 (5) ◽  
pp. 1331-1352
Author(s):  
S. Kumar ◽  
R. Ramesh ◽  
S. Sardesai ◽  
M. S. Sheshshayee
Keyword(s):  
Incubation Time ◽  
Uptake Rate ◽  
Nitrate Uptake ◽  
N Uptake ◽  
Marine Phytoplankton ◽  
Total Production ◽  
New Production ◽  
Urea Uptake ◽  
Uptake Rates

Abstract. We report here the results of three experiments, which are slight variations of the 15N method (JGOFS protocol) for determination of new production. The first two test the effect of (i) duration of incubation time and (ii) concentration of tracer added on the uptake rates of various N-species (nitrate, ammonium and urea) by marine phytoplankton; while the third compares in situ and deck incubations from dawn to dusk. Results indicate that nitrate uptake can be underestimated by experiments where incubation times shorter than 4h or when more than 10% of the ambient concentration of nitrate is added prior to incubation. The f-ratio increases from 0.28 to 0.42 when the incubation time increases from two to four hours. This may be due to the observed increase in the uptake rate of nitrate and decrease in the urea uptake rate. Unlike ammonium [y{=}2.07x{-}0.002\\, (r2=0.55)] and urea uptakes [y{=}1.88x{+}0.004 (r2=0.88)], the nitrate uptake decreases as the concentration of the substrate (x) increases, showing a negative correlation [y{=}-0.76x+0.05 (r2=0.86)], possibly due to production of glutamine, which might suppress nitrate uptake. This leads to decline in the f-ratio from 0.47 to 0.10, when concentration of tracer varies from 0.01 to 0.04μ M. The column integrated total productions are 519 mg C m-2 d-1 and 251 mg C m-2 d-1 for in situ and deck incubations, respectively. The 14C based production at the same location is ~200 mg C m-2 d-1, which is in closer agreement to the 15N based total production measured by deck incubation.

scholarly journals First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas

2018 ◽  
Author(s):  
Bhavya P. Sadanandan ◽  
Jang Han Lee ◽  
Ho Won Lee ◽  
Jae Joong Kaang ◽  
Jae Hyung Lee ◽  
...  
Keyword(s):  
Sea Ice ◽  
Nitrogen Uptake ◽  
N Uptake ◽  
Total Carbon ◽  
The Arctic ◽  
Carbon And Nitrogen ◽  
Uptake Rates ◽  
Wide Range ◽  
Small Phytoplankton

Abstract. Carbon and nitrogen uptake rates by small phytoplankton (0.7–5 μm) in the Kara, Laptev, and East Siberian seas in the Arctic Ocean were quantified using in situ isotope labelling experiments for the first time as part of the NABOS (Nansen and Amundsen Basins Observational System) program during August 21 to September 22, 2013. The depth integrated C, NO3−, and NH4+ uptake rates by small phytoplankton showed a wide range from 0.54 to 15.96 mg C m−2 h−1, 0.05 to 1.02 and 0.11 to 3.73 mg N m−2 h−1, respectively. The contributions of small phytoplankton towards the total C, NO3−, and NH4+ was varied from 24 to 89 %, 32 to 89 %, and 28 to 89 %, respectively. The turnover times for NO3− and NH4+ by small phytoplankton during the present study point towards the longer residence times (years) of the nutrients in the deeper waters, particularly for NO3−. Relatively, higher C and N uptake rates by small phytoplankton obtained during the present study at locations with less sea ice concentrations points towards the possibility of small phytoplankton thrive under sea ice retreat under warming conditions. The high contributions of small phytoplankton towards the total carbon and nitrogen uptake rates suggest capability of small size autotrophs to withstand in the adverse hydrographic conditions introduced by climate change.

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