Total dissolved nitrogen and phosphorus concentrations at US-JGOFS station ALOHA: Redfield reconciliation

1993 ◽  
Vol 41 (1-3) ◽  
pp. 203-208 ◽  
Author(s):  
David M. Karl ◽  
Georgia Tien ◽  
John Dore ◽  
Christopher D. Winn
Keyword(s):  
Nitrogen And Phosphorus ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Station Aloha

scholarly journals Distributions and stoichiometry of dissolved nitrogen and phosphorus in the iron-fertilized region near Kerguelen (Southern Ocean)

2015 ◽  
Vol 12 (2) ◽  
pp. 623-635 ◽  
Author(s):  
S. Blain ◽  
J. Capparos ◽  
A. Guéneuguès ◽  
I. Obernosterer ◽  
L. Oriol
Keyword(s):  
Southern Ocean ◽  
Organic Nitrogen ◽  
Organic Phosphorus ◽  
Polar Front ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Species ◽  
Dissolved Phosphorus ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Preferential Uptake

Abstract. During KEOPS2 (Kerguelen Ocean and Plateau Compared Study 2), we determined dissolved inorganic and organic nitrogen and phosphorus species in the naturally fertilized region of Kerguelen Island (Southern Ocean). Above 150 m, stations were clearly separated by the polar front (PF), with concentrations of NO3-, NO2- and PO43- overall lower north of the PF than south. Though less pronounced, a similar trend was detectable for dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP). At all stations offshore and above the plateau, a subsurface maximum of NH4+ was observed between 50 and 150 m. We examined nutrient stoichiometry by calculating the linear combination N* = [NO3-]-16 [PO43-]. The majority of stations and depths revealed N* close to −3 μM; however, for surface waters north of the PF, N* increased up to 6 μM. This suggests a preferential uptake of PO43- versus NO3- by fast-growing diatoms. Using the tracer TNxs = [TDN]-16[TDP] (TDN, total dissolved nitrogen; TDP, total dissolved phosphorus) revealed that the dissolved organic fraction significantly contributed to changes in TNxs. TNxs values were negative for most stations and depths, and relatively constant in the 0–500 m layer. As for N*, the stations north of the PF had higher TNxs in the 0–100 m layer. We discuss this stoichiometric anomaly with respect to possible external sources and sinks of N and P. Additional data collected in February 2013 at two sites revealed the occurrence of a subsurface minimum of N* located just below the pycnocline, which denotes a layer where remineralization of particulate organic matter with low N : P ratio P, possibly associated with preferential remineralization of P versus N, persists throughout the season.

Preliminary Chemical Characterization of Waters in the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 171-187 ◽  
Author(s):  
F. A. J. Armstrong ◽  
D. W. Schindler
Keyword(s):  
Chemical Characterization ◽  
Specific Conductance ◽  
Canadian Shield ◽  
Nitrogen And Phosphorus ◽  
Experimental Lakes Area ◽  
Mean Values ◽  
Dissolved Phosphorus ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Northwestern Ontario

Water analyses in 1968 and 1969 from 40 small lakes within a small area of the Canadian Shield in northwestern Ontario gave mean values for Ca, Na, Mg, and K of 1.6, 0.9, 0.9, and 0.4 mg/liter with Ca > Na > Mg > K on a molar basis. HCO3, SO4, and Cl (on a smaller number of samples) were 4.1, 3.0, and 1.4 mg/liter. Total CO2 was variable in the range 0.3–12.0 mg/liter. Specific conductance was in the range 10–35 μmho/cm at 25 C and pH 5.4–7.5. Color was < 5–150 Hazen units, and plant pigments (as chlorophyll a) < 1–21 μg/liter. Total dissolved nitrogen was in the range 110–300 mg N/liter and total dissolved phosphorus 3–20 μg P/liter. NO3-N and PO4-P were often undetectable in summer, and reached winter maxima around 100 and 10 μg/liter.Total dissolved nitrogen and phosphorus contents of five lakes were computed at the beginning and end of periods of several weeks during summer stagnation. Changes were negligibly small in three of the deeper lakes, but the two shallowest showed increases of 0.22 and 0.62 g N/m2 and 0.03 and 0.13 g P/m2. Analyses of precipitation and stream waters were used, with stream flow rates, to calculate input and output of nutrients from four of these lakes during the same periods. Retention of nutrients had occurred in all, and it was concluded that in the two deeper lakes nutrients had been lost to the sediments, whereas in the two shallower ones the increases in dissolved nutrients found were derived from the sediments.Analyses of 33 other Canadian Shield lake areas and of 13 other dilute lakes in other regions are tabulated. Comparison with the Experimental Lakes Area (ELA) lakes shows that the latter are more dilute than any in the Shield area except for some in the Northwest Territories, and much more dilute than any others in the world except for some alpine lakes in California.

scholarly journals Salt Marshes as Groundwater Buffers for Development: A Survey of South Carolina Salt Marsh Basins

2021 ◽  
Vol 3 ◽  
Author(s):  
Alicia M. Wilson ◽  
Meghan Shanahan ◽  
Erik M. Smith
Keyword(s):  
South Carolina ◽  
Salt Marshes ◽  
Tidal Creek ◽  
Coastal Development ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Groundwater Samples ◽  
Linear Correlations

Salt marshes serve as zones of intense groundwater mixing and reaction between freshwater uplands and estuaries. This raises the question of whether the impacts of upland development on nutrient and carbon species can be transmitted through salt marshes via groundwater, or whether salt marshes can buffer estuarine waters from coastal development. We sampled groundwater from fifteen tidal creek basins in South Carolina to test for compositional differences associated with development and marsh width. Groundwater samples from near creekbanks and below freshwater uplands were analyzed for salinity, total dissolved nitrogen and phosphorus, and dissolved organic carbon. Analyses revealed significantly higher TDN and TDP concentrations in creekbank samples from developed watersheds, independent of the season. Analyses of upland samples revealed significantly lower DOC concentrations in developed uplands, again independent of season. These results support the hypothesis that development can affect groundwater compositions in coastal groundwater and therefore may affect coastal nutrient and carbon fluxes. However, results also revealed significant linear correlations between marsh width, salinity, and nutrient concentrations in some marshes. These results suggest that salt marshes can act as buffers for development, and specifically suggests that the buffering capacity of salt marshes increases with width. Narrow or trenched salt marshes are far less likely to be effective buffers.

scholarly journals New insights on resource stoichiometry: assessing availability of carbon, nitrogen, and phosphorus to bacterioplankton

2017 ◽  
Vol 14 (6) ◽  
pp. 1527-1539 ◽  
Author(s):  
Ana R. A. Soares ◽  
Ann-Kristin Bergström ◽  
Ryan A. Sponseller ◽  
Joanna M. Moberg ◽  
Reiner Giesler ◽  
...  
Keyword(s):  
General Pattern ◽  
Relative Bioavailability ◽  
Boreal Lakes ◽  
Base Flow ◽  
Nitrogen And Phosphorus ◽  
Dissolved Phosphorus ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Main Fraction ◽  
High Bioavailability

Abstract. Boreal lake and river ecosystems receive large quantities of organic nutrients and carbon (C) from their catchments. How bacterioplankton respond to these inputs is not well understood, in part because we base our understanding and predictions on total pools, yet we know little about the stoichiometry of bioavailable elements within organic matter. We designed bioassays with the purpose of exhausting the pools of readily bioavailable dissolved organic carbon (BDOC), bioavailable dissolved nitrogen (BDN), and bioavailable dissolved phosphorus (BDP) as fast as possible. Applying the method in four boreal lakes at base-flow conditions yielded concentrations of bioavailable resources in the range 105–693 µg C L−1 for BDOC (2 % of initial total DOC), 24–288 µg N L−1 for BDN (31 % of initial total dissolved nitrogen), and 0.2–17 µg P L−1 for BDP (49 % of initial total dissolved phosphorus). Thus, relative bioavailability increased from carbon (C) to nitrogen (N) to phosphorus (P). We show that the main fraction of bioavailable nutrients is organic, representing 80 % of BDN and 61 % of BDP. In addition, we demonstrate that total C : N and C : P ratios are as much as 13-fold higher than C : N and C : P ratios for bioavailable resource fractions. Further, by applying additional bioavailability measurements to seven widely distributed rivers, we provide support for a general pattern of relatively high bioavailability of P and N in relation to C. Altogether, our findings underscore the poor availability of C for support of bacterial metabolism in boreal C-rich freshwaters, and suggest that these ecosystems are very sensitive to increased input of bioavailable DOC.

scholarly journals Automated simultaneous determination of total dissolved nitrogen and phosphorus in seawater by persulfate oxidation method

Talanta Open ◽  
2020 ◽  
Vol 2 ◽  
pp. 100016
Author(s):  
Saori Yasui-Tamura ◽  
Fuminori Hashihama ◽  
Hiroshi Ogawa ◽  
Takashi Nishimura ◽  
Jota Kanda
Keyword(s):  
Simultaneous Determination ◽  
Nitrogen And Phosphorus ◽  
Oxidation Method ◽  
Persulfate Oxidation ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen

scholarly journals New insights on resource stoichiometry: assessing availability of carbon, nitrogen and phosphorus to bacterioplankton

2016 ◽  
Author(s):  
Ana R. A. Soares ◽  
Ann-Kristin Bergström ◽  
Ryan A. Sponseller ◽  
Joanna M. Moberg ◽  
Reiner Giesler ◽  
...  
Keyword(s):  
General Pattern ◽  
Relative Bioavailability ◽  
Boreal Lakes ◽  
Base Flow ◽  
Limiting Factor ◽  
Nitrogen And Phosphorus ◽  
Dissolved Phosphorus ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Nutrient Resources

Abstract. Boreal lake and river ecosystems receive large quantities of organic nutrients and carbon (C) from their 10 catchments. How bacterioplankton respond to these inputs is not well understood, in part because we base our understanding and predictions on "total pools", yet we know little about the stoichiometry of bioavailable elements within the organic matter. We designed bioassays with the purpose to exhaust the pools of readily bioavailable dissolved organic carbon (BDOC), bioavailable dissolved nitrogen (BDN) and bioavailable dissolved phosphorus (BDP) as fast as possible. Applying the method in four boreal lakes at base flow conditions yielded concentrations of bioavailable resources that ranged from 105–693 μg C L−1 for BDOC (2 % of total DOC), 24–288 μg N L−1 for BDN (31 % of total dissolved nitrogen) and 0.2–17 μg P L−1 for BDP (49 % of total dissolved phosphorus). Thus, relative bioavailability increased from carbon (C) to nitrogen (N) to phosphorus (P). We show that the main part of bioavailable nutrient resources is organic, representing 80 % of BDN and 61 % of BDP. In addition, we demonstrate that total C : N and C : P ratios are as much as 13-fold higher than C : N and C : P ratios for bioavailable resource fractions. Further, by applying additional bioavailability measurements to seven widely 20 distributed rivers, we provide support for a general pattern of relatively high bioavailability of P and N in relation to C. Altogether, our findings underscore the role of C as limiting factor for bacterial growth in boreal C-rich freshwaters, and suggest that these ecosystems are very sensitive to increased input of bioavailable DOC.

scholarly journals Quantification of multiple simultaneously occurring nitrogen flows in the euphotic ocean

2016 ◽  
Author(s):  
Min Nina Xu ◽  
Yanhua Wu ◽  
Li Wei Zheng ◽  
Zhenzhen Zheng ◽  
Huade Zhao ◽  
...  
Keyword(s):  
Matrix Equation ◽  
Ammonia Oxidation ◽  
Mass Conservation ◽  
Quantitative Information ◽  
Nitrite Oxidation ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Transformation Rates ◽  
The Matrix ◽  
Multiple Transformation

Abstract. The general features of the N cycle in the sunlit ocean are known, but quantitative information about multiple transformation rates among nitrogen pools, i.e., ammonium (NH4+), nitrite (NO2−), nitrate (NO3−) and particulate/dissolved organic nitrogen (PN/DON), are limited due to methodological difficulties. By adding a single 15N-labelled NH4+ tracer into incubators, we monitor ed the changes in concentration and isotopic composition of the total dissolved nitrogen (TDN), PN, NH4+, NO2−, and NO3− pools to trace the 15N and 14N flows. Based on mass conservation and isotope mass balance, we formulate d a matrix equation that allow edus to simultaneously derive the rates of multiple transformation processes in the nitrogen reaction web . We abandoned inhibitors and minimized the alteration of the system by adding a limited amount of tracer. In one single incubation, solution of the matrix equation provided the rates of NH4+, NO2−, and NO3− uptake; ammonia oxidation; nitrite oxidation; nitrite excretion; DON release; and potentially, the remineralization rate. To our knowledge, this is the first and most convenient method designed to quantitatively and simultaneously resolve complicated nitrogen transformation rates, albeit with some uncertainties. Field examples are given, and c omparisons with conventional labeling methods are discussed.

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