Ancient trees may have played a key role in regulating Earth’s climate during the last ice age — by breathing less efficiently.
Ancient trees may have played a key role in regulating Earth’s climate during the last ice age — by breathing less efficiently.
A new study, led by a researcher at Penn State and published today (Nov. 5) in the journal Nature Geoscience, examined chemical fingerprints in subfossil wood, or preserved trees, from across North America to understand how plants responded to the low carbon dioxide (CO2) levels and cooler temperatures of the last glacial period, about 20,000 years ago.
The researchers found that as temperature and CO2 levels dropped, trees in many locations increased their photorespiration, a process akin to labored breathing for plants and a sign that they are potentially wasting energy and releasing carbon dioxide back into the atmosphere.
The increased release of CO2 may have inadvertently kept the climate just warm enough with enough carbon in the atmosphere for plants to survive — acting as a kind of natural handbrake helping to keep Earth's environment habitable.
Read More: Penn State
Image: Some of the key samples in the study came from the La Brea Tar Pits in Southern California, where researchers analyzed ancient juniper wood preserved in tar. The team found clear signs of elevated photorespiration in the samples, meaning that the trees were releasing CO2 back into the atmosphere nearly as fast they removed it. This archival photo from the original excavations at La Brea Tar Pits shows a tree used in the study. (Credit: Courtesy of La Brea Tar Pits)
