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 ...

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.

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 ...

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.

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 ...