Riverine nitrogen

Comparison of Global Estimates of Contemporary Riverine Nitrogen... 

Figure 36.5 Comparison of global estimates of total riverine N export (Tg N year ) during the early to mid 1990 s from studies reported in the literature. Note that these estimates include loadings to inland regions that don t reach the oceans in addition to the coastal loadings. For the Boyer et al. study, riverine nitrogen flows to the coasts represent 80% of the total global riverine nitrogen fluxes. Modified from Boyer et al. (2006).

There is a great deal of variation in nitrogen fluxes off the landscape in rivers at scales smaller than the continents (Fig. 36.9). For example, within North America contemporary fluxes of nitrogen in rivers per area of watershed are estimated as 76 kg km year in Labrador and the Hudson s Bay area, as 566 kg km year in the Mississippi River basin, and as 1070 kg km year in the northeastern United States from Maine southward through Virginia (Howarth et al., 1996 Fig. 36.10). At finer scales yet, more variation is observed within the major watersheds in the northeastern United States, the riverine nitrogen flux per area varies from a low of 317 kg km year in the Penobscot River basin to 1755 kg km year in the... 

Boyer E. W., Goodale C. L., JaworsM N. A., and Howarth R. W. (2002) Anthropogenic nitrogen sources and relationships to riverine nitrogen export in the Northeastern USA. Biogeo-chemical 57, 137—169. 

Boyer, E.W., Goodale, C.L., Jaworski, N.A. and Howarth R.W. (2002). Effects of anthropogenic nitrogen loading on riverine nitrogen export in the northeastern US. Biogeochemistry, 57 58, 137-169. 

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