Who would have ever thought this was so? Fiords hold as much as ten percent of all carbon captured by the ocean or so it is claimed. It seems high and it is likely to change as we master measurement protocols and the science.
In the meantime we can be delightfully surprised.
It also tells us that fiords need to be exceptionally well protected. simply because the unique conditions produce high chemical stability and actual reduction may take an inordinate amount of time..
Fjords are surprisingly awesome at carbon storage
Posted by U. Florida on
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“Carbon sequestration is the big buzzword, but we’re still getting a
handle on how it works,” says Thomas Bianchi, a geochemist at the
University of Florida. In order to make informed land-use decisions and
accurate climate predictions, “finding and understanding these hot spots
is critical,” he says.
Although fjords represent a tiny fraction of the seas, they store 11
percent of the carbon buried in the oceans—an estimated 18 million
metric tons a year, according to the study in Nature Geosciences.
Locking that carbon away prevents it from converting to carbon
dioxide, one of the greenhouse gases that contributes to a warming
atmosphere. Fjords’ efficiency at storing carbon comes from their deep,
narrow V shape, which allows carbon to sink into low-oxygen zones where
it is less likely to be consumed by aerobic bacteria and re-enter the
atmosphere as a greenhouse gas.
Scientists have known for years that fjords were coastal environments
with high carbon storage, but because they make up just a tenth of a
percent of the world’s oceans, no one realized just how important they
were, Bianchi says.
“Most of the focus has been on the big river deltas, because they
drain so much more surface area in their large watersheds,” he says.
The team studied samples of core and surface sediment from fjords in
New Zealand, then compared their results with previous data from the
Arctic, sub-Arctic Canada, British Columbia, Norway, Sweden, Scotland,
Greenland, Svalbard, Alaska, Chile, and Antarctica.
Their results reveal fjords to be five times more efficient at
sequestration than continental shelves, another key area for carbon
burial. Averaged by area, fjords buried carbon at a rate double that of
the oceans overall.
Bianchi hopes the findings will draw attention to fjords’ importance for better-informed conservation decisions.
“It’s amazing that systems that are so small can have such a huge
global impact,” he says. “It sends the message that fjords are not only
beautiful, they’re providing a very important service.”
Bianchi’s former doctoral student Richard Smith, now a postdoctoral
fellow at the University of Connecticut, led the team, which included
researchers from New Zealand, South Africa, Tulane University in New
Orleans, and the Woods Hole Oceanographic Institution in Massachusetts.
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