Over time, the carbon-14 decays into nitrogen-14; half will do so after about 5,730 years (this is the isotope's half-life). After about 60,000 years, all of the carbon-14 will be gone.

To understand the researcher's approach, it is important to know that nitrogen has two stable isotopes, two different states so to speak, 15 N and 14 N. Gehringer explains, "Nitrogen gas is a ...

Naturally-occurring stable isotopes of water and other substances are used to trace the origin, history, sources, sinks and interactions in water, carbon and nitrogen cycles. Stable isotopes can also ...

N$-dissolved organic nitrogen isotopic signature at this time was significantly higher, 8-12‰, suggesting a phytoplankton source from earlier in the seasonal cycle. Overall, the largest known seasonal ...

Limnology and Oceanography, Vol. 59, No. 5 (2014), pp. 1493-1509 (17 pages) We used δ15N-nitrate ( NO 3 − ) and δ 18 O-NO 3 − to unravel the provenance and fate of NO 3 − in a groundwater-fed estuary.