BOgs have many names: swamps, mosses, bogs, musks, swamps. This linguistic diversity reflects their different influence on the collective imagination and on the planet. Associated with mystery and intrigue, and with people living on the edge, swamps are commonly found on almost every continent on Earth, in a wide range of climates, from the Arctic to the tropics.
But there was a time when there were fewer swamps. Scientists have now learned that these spongy wetlands, composed primarily of sphagnum moss and accumulated organic plant matter known as peat, may have been caused by strong winds. These winds, known as southerly westerlies, blow from west to east across the Southern Hemisphere, through southern Chile and Patagonia, New Zealand, Tasmania and the Falkland Islands. And now they're shifting again, which could tell us something about where Earth's climate is heading. Scientists have published their conclusions V Nature.
“We found a clear pattern,” said Zoe Thomas, lead author from the University of Southampton, in her paper. statement. “Major peat growth occurred at the same time as winds shifted north or south.” These changes in southerly westerly winds, which influence weather patterns and ocean currents, also coincided with changes in atmospheric carbon dioxide levels, suggesting that swamps may serve as natural climate time markers.
Read more: “Swamp problem»
A team of scientists radiocarbon dated the lower peat layers of swamps found in the Falkland Islands off the coast of Argentina, and compared this data with the age of peat taken from Patagonia, New Zealand, Tasmania and the sub-Antarctic islands. They found that the swamps began to form at different times at different latitudes.
About 21,000 years ago, after the Last Glacial Maximum, when the ice sheets reached their greatest extent, peat bogs began to rise in the southern mid-latitudes. Then, during a 2,000-year cooling event known as the Antarctic cooling reversal, between 14,700 and 13,000 years ago, peatlands suddenly began to form further north. When the cold weather passed, they moved south again. These changes in climate and peat growth coincided with changes in the southerly westerly winds.
Read more: “We need to talk about peat»
The winds change again, but this time they are heading towards the South Pole. If this trend continues, it could threaten the ocean's ability to act as a carbon sink. This shift has already played a role in increased droughts and wildfires in the southern hemisphere.
As these winds move, the marshes provide quiet clues about where our climate might go next.
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Main image: dvlcom – www.dvlcom.co.uk / Shutterstock.
