The Role of Dissolved Organic Carbon, Dissolved Organic Nitrogen, and Dissolved Inorganic Nitrogen in a Tropical Wet Forest Ecosystem

Ecosystems ◽  
2005 ◽  
Vol 8 (4) ◽  
pp. 339-351 ◽  
Author(s):  
Luitgard Schwendenmann ◽  
Edzo Veldkamp
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Forest Ecosystem ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Dissolved Inorganic Nitrogen ◽  
Tropical Wet Forest

scholarly journals Net accumulation and flux of dissolved organic carbon and dissolved organic nitrogen in marine plankton communities

2000 ◽  
Vol 45 (5) ◽  
pp. 1097-1111 ◽  
Author(s):  
Morten Søndergaard ◽  
Peter J. le B. Williams ◽  
Gustave Cauwet ◽  
Bo Riemann ◽  
Carol Robinson ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Marine Plankton ◽  
Plankton Communities

Dissolved organic carbon and dissolved organic nitrogen concentrations and exports upstream and downstream of the Dallas–Fort Worth metropolis, Texas, USA

2016 ◽  
Vol 67 (9) ◽  
pp. 1326 ◽  
Author(s):  
J. A. Aitkenhead-Peterson ◽  
M. K. Steele
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Significant Relationship ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Urban Land Use ◽  
Fort Worth ◽  
Sewage Discharge ◽  
Effluent Discharge

Concentrations and export of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) from terrestrial landscapes to near-coastal zones vary with land use. Information on (DOC) and (DON) concentrations and exports from urban ecosystems is sparse; thus, their source from within urbanised watersheds such as soil or vegetation or from permitted sewage discharge is unknown. We examined DOC and DON concentrations and exports in four gauged subwatersheds in the humid subtropical, upper Trinity River basin, upstream and downstream of the Dallas–Fort Worth metropolis in Texas, USA. Annual average DOC concentrations ranged from 5.7±0.4 to 6.4±0.8mgL–1 and DON concentrations ranged from 0.31±0.05 to 0.33±0.14mgL–1. Dissolved organic carbon exports, which included permitted sewage discharge, ranged from 522kgkm–2 year–1 above Dallas–Fort Worth to 3637kgkm–2 year–1 below Dallas–Fort Worth. Permitted effluent discharge contributed between 1 and 35% of DOC loading above and below the Dallas–Fort Worth metropolis. DON exports ranged from 27 to 179kgkm–2 year–1 above and below Dallas–Fort Worth respectively. There was difficulty apportioning permitted effluent-discharge contribution to DON because of the transformations among nitrogen-species. A moderate but significant relationship was found between DOC and sodium concentrations (R2=0.45; P<0.0001; n=40) and between DOC and potassium concentrations (R2=0.45; P<0.0001; n=40). Dissolved organic nitrogen also displayed a significant relationship with sodium (R2=0.33; P<0.001; n=40) and potassium (R2=0.59; P<0.001; n=40), suggesting that increases in these cations to aquatic ecosystems may induce increases in DOC and DON concentrations. Although DOC export was significantly correlated with medium-density urban land use (r=0.96; P<0.05: n=4), DON export was not (r=0.93; P>0.05; n=4), suggesting that land-management practices and permitted point-source discharges have a significant effect on aquatic DOC and DON concentrations and exports derived from urban watersheds.

Forest detritus and cycling of nitrogen in a mountain lake

1991 ◽  
Vol 21 (7) ◽  
pp. 990-998 ◽  
Author(s):  
Robert C. Wissmar
Keyword(s):  
Total Nitrogen ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Mountain Lake ◽  
Dissolved Inorganic Nitrogen ◽  
Microbial Oxidation ◽  
Nitrogen Fluxes ◽  
Nitrogen Concentrations ◽  
Definition Of

Small lakes of forested watersheds can receive large subsidies of forest matter, but little is known about the material's role in the cycling of nutrients within these ecosystems. This paper examines the influence of detritus and dissolved nitrogen from a forest on the nitrogen cycle of a small subalpine lake in the Cascade Mountains of Washington during the ice-free period (98 days). Relationships between changing detrital microbial biomass, oxygen uptake rates, and water conditions indicate that dissolved inorganic nitrogen concentrations and water temperatures control the decomposition of the nitrogen-depleted detritus. The microbial respiration rates suggest the probable co-occurrence of several microbial oxidation and reduction reactions that could be cycling nitrogen in oxic–anoxic interfaces of detrital deposits, sediments, and riparian areas. Estimates of nitrogen gains and losses (3 and 7%, respectively) by forest detritus are low in comparison with total nitrogen uptake and releases within the lake during the study period (378 and 347 mg•m−2, respectively) and point to the need to examine other methods for measuring detrital nitrogen fluxes. The total nitrogen input to the lake (2600 mg•m−2 for the study period) from the watershed exceeds the lake output (2120 mg•m−2 for the study period). The low output of total nitrogen appears to be due to retention of dissolved inorganic nitrogen and particulate organic nitrogen within the lake. Most dissolved inorganic nitrogen retained is nitrate suggesting possible losses through denitrification. Dissolved organic nitrogen is the major proportion of the total nitrogen fluxes, but related mass balance errors indicate the need for further definition of both the sources and fates of dissolved organic nitrogen for the ecosystem.

Nitrogen removal and cycling in restored wetlands used as filters of nutrients for agricultural runoff

1997 ◽  
Vol 35 (5) ◽  
pp. 255-261 ◽  
Author(s):  
Francisco A. Comín ◽  
Jose A. Romero ◽  
Valeria Astorga ◽  
Carmen García
Keyword(s):  
Total Nitrogen ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Nitrogen Retention ◽  
Growing Season ◽  
Agricultural Runoff ◽  
Dissolved Inorganic Nitrogen ◽  
Restored Wetlands ◽  
Irrigation Network

Four restored wetlands dominated by Phragmites australis, Typha latifolia and Scirpus lacustris were used to improve the quality of agricultural runoff in the Delta of the Ebro River (NE Spain) in 1993. The wetlands were continuously flooded with water from a ricefield irrigation network during the growing season and received water with between 0-270 mg m−2d−1 of total nitrogen, 29-105 mg m−2d−1 of dissolved inorganic nitrogen and 0-27 mg m−2d−1 of dissolved organic nitrogen. Surface outflows contained between 0-80 mg m−2d−1 of total nitrogen, 0-12 mg m−2d−1 of dissolved inorganic nitrogen and 1-19 mg m−2d−1 of dissolved organic nitrogen. The nitrogen retention efficiency was close to 100% of the input, except for dissolved organic nitrogen at the end of the growing season. The denitrification rates measured by the acetylene reduction in the sediment ranged between 0 and 3.46 mg N m−2 d−1 and represented between 0 and 12% of the inflowing dissolved inorganic nitrogen. Emergent macrophytes accumulated between 20 and 100 mg N m−2 d−1, which accounts for between 66 and 100% of the inflowing dissolved inorganic nitrogen. The wetland sediment accumulated between 111 and 250 mg N m−2 d−1 during the six month growing season. The removal rate constants calculated according to a first - order plug - flow kinetics, were between 0.01-0.075 m d−1 for total nitrogen and 0.01-0.3 m d−1 for dissolved inorganic nitrogen. Plant uptake, detritus accumulation and decomposition, and nitrogen recycling in the sediment are major processes for nitrogen retention and recycling in the wetlands. This type of wetlands, restored from ricefields, act as highly efficient water polishing filters for agricultural runoff and, at the same time, can contribute to increase the habitat biodiversity of large areas where rice is cultivated extensively.

Dialysis is superior to anion exchange for removal of dissolved inorganic nitrogen from freshwater samples prior to dissolved organic nitrogen determination

2012 ◽  
Vol 9 (6) ◽  
pp. 529 ◽  
Author(s):  
Daniel Graeber ◽  
Björn Gücker ◽  
Elke Zwirnmann ◽  
Brian Kronvang ◽  
Christoph Weih ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Treatment Technique ◽  
Dissolved Inorganic Nitrogen ◽  
Recovery Rates ◽  
Nitrogen Determination ◽  
Pre Treatment

Environmental context Aquatic ecosystem health may be adversely affected by dissolved organic nitrogen pollution, and accurate analytical techniques are needed to assess these effects. Our study shows that dialysis is the best sample pre-treatment technique to increase the accuracy of dissolved organic nitrogen determination. It will improve analysis and understanding of the role of dissolved organic nitrogen in the nitrogen cycle of affected aquatic ecosystems. Abstract Dissolved organic nitrogen (DON) is usually determined as the difference between total dissolved nitrogen (TDN) and dissolved inorganic nitrogen (DIN). When applying this approach to samples with high DIN concentrations, there is a risk that small relative errors in TDN and DIN measurements may propagate into high absolute errors of the determined DON concentration. To reduce such errors, two pre-treatment methods have been suggested for the removal of DIN before the determination of DON: anion-exchange pre-treatment (AEP) and dialysis pre-treatment (DP). In this study, we tested the suitability of AEP and DP for DIN removal in order to increase the accuracy of DON determination of freshwater samples. The AEP performed well for standard compounds, yielding high dissolved organic carbon (DOC) recovery rates and >99 % removal of nitrate, whereas DON recovery rates varied and no removal occurred for ammonium and nitrite. However, AEP proved not to be suitable for natural samples, as it removed 36–74 % DOC and up to 83 % DON. In contrast, after 72 h of DP, 17–32 % DOC and DON had been removed from the natural samples, whereas >98 % nitrate was removed in all but one case, and >87 % of the ammonium and nitrite were removed. Moreover, we found that DP results in a significant increase in DON determination accuracy. In conclusion, DP is a useful measure to increase DON determination accuracy in natural freshwater samples with high DIN-to-TDN ratios, whereas AEP is not recommended for DON determination of natural freshwater samples.

scholarly journals Technical Note: Comparison between a direct and the standard, indirect method for dissolved organic nitrogen determination in freshwater environments with high dissolved inorganic nitrogen concentrations

2012 ◽  
Vol 9 (11) ◽  
pp. 4873-4884 ◽  
Author(s):  
D. Graeber ◽  
J. Gelbrecht ◽  
B. Kronvang ◽  
B. Gücker ◽  
M. T. Pusch ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Measurement Accuracy ◽  
Inorganic Nitrogen ◽  
Size Exclusion ◽  
Standard Approach ◽  
Dissolved Inorganic Nitrogen ◽  
Recovery Rates ◽  
Freshwater Systems

Abstract. Research on dissolved organic nitrogen (DON) in aquatic systems with high dissolved inorganic nitrogen (DIN, the sum of NO3–, NO2– and NH4+) concentrations is often hampered by high uncertainties regarding the determined DON concentration. The reason is that DON is determined indirectly as the difference between total dissolved nitrogen (TDN) and DIN. In this standard approach to determine DON concentrations, even small relative measurement errors of the DIN and TDN concentrations propagate into high absolute errors of DON concentrations at high DIN : TDN ratios. To improve the DON measurement accuracy at high DIN : TDN ratios, we investigated the DON measurement accuracy of this standard approach according to the DIN : TDN ratio and compared it to the direct measurement of DON by size-exclusion chromatography (SEC) for freshwater systems. For this, we used standard compounds and natural samples with and without DIN enrichment. We show that for the standard approach, large errors of the determined DON concentrations at DIN : TDN ratios >0.6 occur for both standard compounds and natural samples. In contrast, measurements of DON by SEC always gave low errors at high DIN : TDN ratios due to the successful separation of DON from DIN. For SEC, DON recovery rates were 91–108% for five pure standard compounds and 89–103% for two standard compounds, enriched with DIN. Moreover, SEC resulted in 93–108% recovery rates for DON concentrations of natural samples at a DIN : TDN ratio of 0.8 and the technique was successfully applied to a range of samples from waste water treatment plants to forest and agricultural streams. With 2.5 h of measurement time per sample, SEC is slower, but more accurate than the standard approach for determination of DON concentrations in freshwaters with DIN : TDN ratios >0.6. To sum up, the direct DON measurement by SEC enables better understanding of the nitrogen cycle of urban and agricultural freshwater systems.

scholarly journals The importance of riparian zones on stream carbon and nitrogen export in a temperate, agricultural dominated landscape

2012 ◽  
Vol 9 (6) ◽  
pp. 7465-7497 ◽  
Author(s):  
T. Wohlfart ◽  
J.-F. Exbrayat ◽  
K. Schelde ◽  
B. Christen ◽  
T. Dalgaard ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Agricultural Land ◽  
Stream Water ◽  
Soil Types ◽  
Organic Soils ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen

Abstract. The surrounding landscape of a stream has crucial impacts on the aquatic environment. This study pictures the hydro-biogeochemical situation of the Tyrebaekken creek catchment in central Jutland, Denmark. The intensively managed agricultural landscape is dominated by rotational croplands. One northern and one southern stream run through the catchment before converging to form a second order brook. The small catchments mainly consist of sandy soil types besides organic soils along the riparian zone of the streams. The aim of the study was to characterise the relative influence of soil type and land use on stream water quality. Nine snapshot sampling campaigns were undertaken during the growing season of 2009. On each sampling day, 20 points along the stream were sampled as well as eight drain outlets and two groundwater wells. Total dissolved nitrogen, nitrate, ammonium nitrogen and dissolved organic carbon (DOC) concentrations were measured and dissolved organic nitrogen (DON) was calculated for each grabbed sample. Electro-conductivity, pH and flow velocity were measured during sampling. Statistical analyses showed significant differences between the northern, southern and converged stream parts, especially for nitrate concentrations with average values of 9.6 mg N l−1, 1.4 mg N l−1 and 3.0 mg N l−1, respectively. Furthermore, throughout the sampling period DON concentrations increased from 0.1 mg N l−1 to 2.8 mg N l−1 and from 0.1 mg N l−1 to 0.8 mg N l−1in the northern and southern streams, respectively. This corresponded to a contribution of up to 81% to total dissolved nitrogen. Multiple-linear regression analyses performed between chemical data and landscape charateristics showed a significant negative influence of organic soils on instream N concentrations and corresponding losses in spite of their overall minor share of the agricultural land (12.9%). On the other hand, organic soil frequency was positively correlated to the corresponding dissolved organic carbon concentrations. Croplands also had a significant influence but with weaker correlations. For our case study we conclude that soil types and corresponding biogeochemical properties have a major influence on stream water chemistry. Meanwhile, the contribution of dissolved organic nitrogen to the total nitrogen budget was substantial in this agricultural dominated landscape.

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