Seabird poop plays key role in Arctic climate puzzle
Friday, November 18, 2016, 3:18 PM - Researchers from Dalhousie University have been scouring the Canadian Arctic for the answer to a summertime mystery for several years, and it turns out the answer was right under their feet.
It's bird poop.
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In a report released earlier this week, the team from Dalhousie's Department of Physics and Atmospheric Science identifies seabird guano as the source of the mysteriously high concentrations of ammonia in the summertime Arctic air. "Every summer, tens of millions of seabirds flock to the Arctic," says the official release from the university, "where their nitrogen-rich diets lead to droppings, or guano, that release ammonia into the air."
This ammonia joins with other particles rising from the ocean to make cloud condensation nuclei - the seeds around which water droplets condense in the atmosphere to form clouds. More seeds generally means smaller droplets overall, as the same amount of moisture gets spread over more area.
The effect is brighter clouds, and brighter clouds are able to reflect more sunlight - keeping the area below cooler.
In the university's statement, study co-author Dr. Betty Croft said it is "very important to understand the set of interconnections that exist within the Arctic climate system," particularly because clouds play a key role in controlling temperatures in the region.
The seabird guano - cloud albedo connection. Image courtesy Nature Communications.
Unfortunately for the rapidly-warming Arctic, the impact of the cooling - while important to understand - is minor compared to the overall warming of the changing environment.
It's also important to note that while the more-reflective clouds are more efficient at repelling the sun's incoming energy, they're also better at trapping heat escaping from Earth's surface - a warming effect.
In their discussion, the study authors also caution that, "given the accelerated rate of Arctic warming, seabird numbers and migratory patterns may change, altering the seabird-guano ammonia emissions in the Arctic," suggesting that the cooling effect may also be subject to change in the future.
"The findings are surprising, and support the precautionary principle," says one of the study's co-authors, Dr. Randall Martin, "there are likely [other, similar] interconnections between the living and non-living components of Earth's climate system that we don't understand yet."
Watch below: See cloud particles in action with this cloud in a bottle.