Using core samples of the seabed in three locations, the scientists measured the isotopic ratio of nitrogen - 15 to nitrogen - 14 in the organic matter therein; the ratio can be used to estimate the extent of anoxia in these OMZs. (sciencedaily.com)
Anemic anoxia occurs when the blood does not have enough oxygen in it Brain injury from blood that does not carry enough oxygen (gjel.com)
The most interesting and worrying result of the analysis, according to co-author Stephen Romaniello, is how similar the marine anoxia of the period to the oceanic changes observed at present. (techtimes.com)