Seabird guano releases more ammonia at tropics

March 14, 2014
Seabird guano releases more ammonia at tropics

Seabird guano emits more ammonia into the atmosphere in warmer and wetter climates, scientists have found.

A new study, published in Atmosphere Environment, shows for the first time how the climate interacts with nitrogen in layers of guano droppings on the ground.

To investigate this, the researchers studied how much ammonia is emitted from seabird excreta around the world. Some ammonia in the atmosphere is produced by bacteria metabolising nitrogen and water in soils and these manures.

Seabird's diets are rich in nitrogen from the marine plant life and fish they eat. This nitrogen is often excreted across a huge area near their nesting sites. In dry climates the guano at these sites builds up over time and creates a nitrogen-rich material that is often mined for fertiliser.

But over time the nitrogen in the guano breaks down to form ammonia, which is released into the atmosphere.

The international team visited two large colonies of seabirds; one at Ascension Island in the southern Atlantic and another at Michaelmas Island, off the south coast of Australia, to measure both the and environmental conditions.

'Ammonia were much higher in the warmer climates, as the uric acid changes to form ammonia and is then released into the atmosphere much more quickly,' says Dr Stuart Riddick of King's College London and the NERC Centre for Ecology & Hydrology (CEH), lead researcher of the study.

Despite being similar temperatures at the two sites, the team found that 67 per cent of the nitrogen in the guano on Michaelmas Island was emitted as ammonia, compared to just 32 per cent at Ascension Island.

'Although both Ascension and Michaelmas Islands are a very similar temperature, Michaelmas is much wetter,' Riddick says. 'The more frequent rain events mean ammonia emissions are a lot higher. The bacterial ammonification of uric acid requires water to work, so the emissions were much lower on Ascension.'

If scientists understand how fertiliser interacts with climate, they can build computer models that show how much ammonia is given off in different climates from a range of manure and synthetic fertilizers, which will help improve knowledge of the cycle under different environmental conditions.

'If you put fertiliser on a field in central Africa, we need to know if it will react differently, compared with, for example, under UK conditions. This will help us predict the emissions much better and subsequent effects of the on ecosystems and the , which is not well understood at present,' says Riddick.

Explore further: Seabird ammonia emissions contribute to atmospheric acidity

Related Stories

Seabird ammonia emissions contribute to atmospheric acidity

September 23, 2008

Ammonia emissions from seabirds have been shown to be a significant source of nitrogen in remote coastal ecosystems, contributing to nutrient enrichment (eutrophication) and acidification in ecosystems. While most ammonia ...

One tree likes seabird poop, the next prefers fresh air

January 24, 2014

Off the west coast of Peru, seabirds deposit thick layers of guano that accumulates on the ground because of the lack of rain. Guano has historically played a key role in agriculture worldwide because it is rich in plant ...

USDA patents method to reduce ammonia emissions

November 1, 2012

Capturing and recycling ammonia from livestock waste is possible using a process developed by U.S. Department of Agriculture (USDA) researchers. This invention could help streamline on-farm nitrogen management by allowing ...

Telescope detects rare form of nitrogen in comet ISON

February 20, 2014

A team of astronomers, led by Ph.D. candidate Yoshiharu Shinnaka and Professor Hideyo Kawakita, both from Kyoto Sangyo University, successfully observed the Comet ISON during its bright outburst in the middle of November ...

Recommended for you

Mountain glaciers shrinking across the West

October 22, 2017

Until recently, glaciers in the United States have been measured in two ways: placing stakes in the snow, as federal scientists have done each year since 1957 at South Cascade Glacier in Washington state; or tracking glacier ...

Carbon coating gives biochar its garden-greening power

October 20, 2017

For more than 100 years, biochar, a carbon-rich, charcoal-like substance made from oxygen-deprived plant or other organic matter, has both delighted and puzzled scientists. As a soil additive, biochar can store carbon and ...

Cool roofs have water saving benefits too

October 20, 2017

The energy and climate benefits of cool roofs have been well established: By reflecting rather than absorbing the sun's energy, light-colored roofs keep buildings, cities, and even the entire planet cooler. Now a new study ...


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.