Dissolved inorganic nitrogen

Fig. 2 Longitudinal changes in nutrient concentrations below the effluent input of a WWTP without tertiary treatment in La Tordera Stream. Values are the average ( SEM) of monthly measurements done over a year (see more details in [47]). In the left panel, note the net decline of ammonium concentration with concomitant net increases in nitrate concentration, suggesting a potential hot spot for nitriflcation. However, in the latest meters downstream, dissolved inorganic nitrogen (DIN) tends to decrease, which indicates net lost of DIN possibly due to denitrification. The right panel shows net changes in phosphate and dissolved organic carbon (DOC) concentrations. While phosphate does not exhibit any clear trend on an annual basis, DOC seems to decline similarly to DIN, which supports the relative dominance of denitrification...

Dise NB, Rothwell JJ, Gauci V, van der Salm C, de Vries W (2009) Predicting dissolved inorganic nitrogen in European forests using two independent databases. Sci Total Environ 407 1798-808... 

Equation 8.4 predicts that aerobic respiration should release dissolved inorganic nitrogen and phosphorus into seawater in the same ratio that is present in plankton, i.e., 16 1. As shown in Figure 8.3, a plot of nitrate versus phosphate for seawater taken from all depths through all the ocean basins has a slope close to 16 1. Why do both plankton and seawater have an N-to-P ratio of 16 1 Does the ratio in seawater determine the ratio in the plankton or vice versa Current thinking is that the N-to-P ratio of seawater reflects a quasi steady state that has been established and stabilized by the collective impacts of several biological processes controlled by marine plankton. 

Deviations from the Redfield-Richards ratio can also be caused by remineralization that proceeds by processes other than aerobic respiration. As shown in Figure 10.6, water samples obtained from depths where denitrification has occurred have lower dissolved inorganic nitrogen concentrations ([NOj ] + [NOH) than would be predicted from their AOU. During denitrification, nitrate is first reduced to nitrite and then to N2,... 

The observed slow increase in 15N content of POM at the start of the experiment was probably caused by isotopic dilution from unlabeled dissolved inorganic nitrogen (DIN) brought into the lake from the catchment or input from the hypolimnion via cross-thermocline mixing. Horizontal mixing in the epilimnion is rapid in this small lake samples of moss and periphyton from next to the 15N drippers and on the opposite shores of the lake were equally labeled. 

Estimates are based on ratios of dissolved inorganic nitrogen contrations (N03 + NH4+) to total phosphorus concentrations. Excess phosphorus calculated as the amount of added DIN necessary to increase the DIN TP ratio to 2.0. fData are from Kanciruk et al. (202) excluding lakes with total phosphorus >0.65 p mol/L (20 pg/L). rfData are from reference 203, excluding lakes with total phosphorus >0.65 mol/L (20 pg/L). 

Middleburg, J. J., and J. Nieuwenhuize. 2000a. Uptake of dissolved inorganic nitrogen in turbid tidal estuaries. Marine Ecology Progress Series 192 79—88. 

Figure 5.5 Nitrous oxide emission rates (mmol m-2 d-1) versus dissolved inorganic nitrogen (DIN) loading (N m-2 d-1) in mesocosm experiments at the Marine Ecosystem Research Laboratory. (Modified from Seitzinger and Nixon, 1985.)...

Figure 10.2 Latitudinal export (Tg N y ) of dissolved inorganic nitrogen (DIN) in Northern and Southern Hemispheres. (Modified from Seitzinger et al., 2002a.)...

Horrigan, S.G., Montoya, J.P., Nevins, J.L., and McCarthy, J.J. (1990) Natural isotopic composition of dissolved inorganic nitrogen in the Chesapeake Bay. Estuar. Coastal Shelf Sci. 30, 393 110. 

Fig. 7.11 Nitrogen balance during the H2O2-UV treatment ofEDTA (QoHt6N208). DN dissolved total nitrogen, DIN dissolved inorganic nitrogen, DON dissolved organic nitrogen. DN was calculated according to DN = ELi

Dissolved inorganic nitrogen (DIN) 16.8 pmol L l DeMaster and Pope, 1996... 

Kristensen, E., Jensen, M. H., and AUer, R. C. (1991). Direct measurement of dissolved inorganic nitrogen exchange and denitrification in individual polychaete Nereis virens) burrows. J. Mar. Res. 49, 355-377. 

Dam, H. G., Roman, M. R., and Youngbluth, M. J. (1995). Downward export of respiratory carbon and dissolved inorganic nitrogen by diel-migrant mesozooplankton at the JGOFS Bermuda time-series station. Deep Sea Res. 142(7), 1187-1197. 

Figure 9.9 Mean annual N load for the Mississippi River at Belle Chase, LA (1979—1981), hy N form, including total nitrogen (closed triangles), dissolved inorganic nitrogen (open circles), dissolved organic nitrogen (closed circles), and particulate nitrogen (open triangles) (Alexander...

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