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

Arctic wintertime sea ice extent is among lowest on record

March 23, 2018

Sea ice in the Arctic grew to its annual maximum extent last week, and joined 2015, 2016 and 2017 as the four lowest maximum extents on record, according to scientists at the NASA-supported National Snow and Ice Data Center ...

Germany was covered by glaciers 450,000 years ago

March 23, 2018

The timing of the Middle Pleistocene glacial-interglacial cycles and the feedback mechanisms between climatic shifts and earth-surface processes are still poorly understood. This is largely due to the fact that chronological ...

Wood pellets: Renewable, but not carbon neutral

March 22, 2018

A return to firewood is bad for forests and the climate. So reports William Schlesinger, President Emeritus of the Cary Institute of Ecosystem Studies, in an Insights article published today in the journal Science.

The tradeoffs inherent in earthquake early warning systems

March 22, 2018

A team of researchers with the U.S. Geological Survey and the California Institute of Technology has found that modern earthquake early warning (EEW) systems require those interpreting their messages to take into consideration ...


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.