Estimates of anthropogenic nitrogen in the ocean may be high

December 1, 2014, Wiley

Inundation of nitrogen into the atmosphere and terrestrial environments, through fossil fuel combustion and extensive fertilization, has risen tenfold since preindustrial times according to research published in Global Biogeochemical Cycles. Excess nitrogen can infiltrate water tables and can trigger extensive algal blooms that deplete aquatic environments of oxygen, among other damaging effects.

Although scientists have extensively studied the effects of excess nitrogen in terrestrial habitats, the effect on the remains unknown. Altieri et al. point out that it is incredibly important to understand where is ending up so that scientists can better quantify the human impact on the Earth's .

To investigate the origin of nitrogen that reaches the open ocean, the authors analyzed rain samples from Bermuda. The authors specifically looked at the different isotopes of nitrogen found in the rainwater's ammonium molecules, which indicates whether the nitrogen originated from anthropogenic sources, from land, or from the ocean.

Using a model that described sources and sinks of the nitrogen, the authors found that certain nitrogen isotopes likely represent ammonium recycled from the ocean, rather than ammonium inputted from an external source, such as pollution from human activities. The authors note that although these findings imply that the anthropogenic contribution of ammonium to the open ocean could be smaller than previously thought, further research is needed on a larger scale to fully understand nitrogen transfer in the marine atmosphere.

Explore further: Researchers track ammonium source in open ocean

More information: Altieri, K. E., M. G. Hastings, A. J. Peters, S. Oleynik, and D. M. Sigman (2014), Isotopic evidence for a marine ammonium source in rainwater at Bermuda, Global Biogeochem. Cycles, 28, 1066-1080, DOI: 10.1002/2014GB004809.

Related Stories

Researchers track ammonium source in open ocean

October 29, 2014

To understand the extent to which human activities are polluting Earth's atmosphere and oceans, it's important to distinguish human-made pollutants from compounds that occur naturally. A recent study co-authored by a Brown ...

Recommended for you

Coffee-based colloids for direct solar absorption

March 22, 2019

Solar energy is one of the most promising resources to help reduce fossil fuel consumption and mitigate greenhouse gas emissions to power a sustainable future. Devices presently in use to convert solar energy into thermal ...

NASA instruments image fireball over Bering Sea

March 22, 2019

On Dec. 18, 2018, a large "fireball—the term used for exceptionally bright meteors that are visible over a wide area—exploded about 16 miles (26 kilometers) above the Bering Sea. The explosion unleashed an estimated 173 ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.