Figure 3.

Mass balance of 15NO3− added in low dose to an unenriched reference salt marsh creek (a) and in high dose to a NO3−enriched salt marsh creek (b) during a paired 15N isotope enrichment experiment (Drake et al. 2009). The reference marsh retained 98.8% of added NO3−, compared with 54.5% in the enriched marsh. The percentages are the percentage of added NO3− found in each marsh pool after 5 days of dosing. NO3− that was unaccounted for was assumed to be lost via dissimilatory microbial processes such as denitrification. Asterisk indicates that the value was estimated and not directly measured. More details on the experimental design and measurements can be found in Drake and colleagues (2009). Source: The images of marsh vegetation were compiled from the IAN symbol repository.