Researchers go cuckoo: Antarctic penguins release an extreme amount of laughing gas

ANTARCTICA – In a new study, University of Copenhagen researchers showed that penguins in Antarctica give out copious amounts of nitrous oxide via their faeces – so much so, that the researchers went "cuckoo" from being surrounded by penguin poo.
 
On the Atlantic island of South Georgia, king penguins live in huge colonies. They spend their days eating krill, squid and fish, feeding their chicks and producing guano (poo). Nothing mind-boggling about that, you might say.

But there is something very special about the comings and goings of king penguins. The birds release tremendous amounts of nitrous oxide, better known as laughing gas, via their guano, according to the 2019 study.

"Penguin guano produces significantly high levels of nitrous oxide around their colonies. The maximum emissions are about 100 times higher than in a recently fertilised Danish field," explained Professor Bo Elberling, of the University of Copenhagen's Department of Geosciences and Natural Resource Management.

"It is truly intense – not least because nitrous oxide is 300 times more polluting than CO2."

Besides being a strain on the climate, nitrous oxide has an effect very similar to the sedative laughing gas used in the dentist's office.

"After nosing about in guano for several hours, one goes completely cuckoo," Professor Elberling said. 

 "One begins to feel ill and get a headache. The small nitrous oxide cylinders that you see lying in and floating around Copenhagen are no match for this heavy dose, which results from a combination of nitrous oxide with hydrogen sulphide and other gases."

How penguin poop turns into nitrous oxide
Penguins' favorite foods are fish and krill, both of which contain large amounts of nitrogen absorbed from phytoplankton in the ocean.

Once penguins have filled their bellies, nitrogen is released from their faeces into the ground. Soil bacteria then convert the substance into nitrous oxide, a greenhouse gas.

"It is clear to us that the level of nitrous oxide is very high in places where there are penguins – and thereby guano – and vice versa, lower in places where there is none," explained Professor Elberling.

Knowing how penguin droppings affect the Earth and atmosphere is highly relevant in the fight against climate-damaging greenhouse gases.

Elberling continued, "While nitrous oxide emissions in this case are not enough to impact Earth's overall energy budget, our findings contribute to new knowledge about how penguin colonies affect the environment around them, which is interesting because colonies are generally becoming more and more widespread."

He concluded, "We should learn from this in relation to Danish agriculture, where large quantities of nitrous oxide are emitted by nitrogen fertilisers in fields. One of the things we can learn, for example, is how and when to fertilise vis-à-vis the optimal conditions for soil bacteria to produce nitrous oxide."

Their recent study is published in the scientific journal Science of the Total Environment.

Source
University of Copenhagen, Researchers go cuckoo: Antarctic penguins release an extreme amount of laughing gas [press release], 14 May 2020

Journal citation

Wang, P., D'Imperio, L., Biersmade, E. M., Rannikuc, R., Xu, W., Tian, Q., Ambus, P., & Elberling, B.(2020). Combined effects of glacial retreat and penguin activity on soil greenhouse gas fluxes on South Georgia, sub-Antarctica. Science of the Total Environment, 718, 20 May 2020, 135255. 

https://doi.org/10.1016/j.scitotenv.2019.135255