Pollen Grains Preserve Clues About the Earth From the Time When an Asteroid Struck 66 Million Years Ago

Nature carried with it the traces of a past time, and every inch of its being revealed something new and unknown. One such material in nature was pollen grains that were not only allergens but also nature’s time capsules. Scientists studied the history of our planet’s environments from pollen, as they had tough shells and got trapped as sediments, according to The Conversation. It was found at the bottom of lakes, oceans, and riverbeds, giving insights into pollen-producing plants of that habitat. They carried evidence of vegetation, climate, and human activity and reflected on the traces of events, such as the impact of asteroids or the collapse of civilizations.

Palynologists studied the pollen from different environments and combined their findings of microscopic pollen grains. The asteroid strike that wiped out the dinosaurs sent a tidal wave to North America, where marine fossils and rocks revealed fossilized pollen. The Late Cretaceous and Early Paleocene pollen revealed the changes in the ecosystem that were disrupted by the asteroid. Gymnosperms such as pines, ferns, flowering plants, grasses, herbs, and palm trees had a pattern where some of them disappeared after the impact. This indicated that the vegetation of the region underwent significant changes before the pollen reemerged and the habitat stabilized.

Fossilized pollen grains traced the slow and massive changes along the eastern Gulf Coast states of Mississippi and Alabama. Pollen released by Sequoia-type trees in the coastal region revealed the rise of sea levels and the flooding of low-level regions during the Early Oligocene period. Researchers identified a distinct change in pollen released by Sequoia-type trees, giant conifers that once dominated the coastal plains. As a biological marker, the pollen showed how far the shoreline had shifted, according to The Conversation. The effects of long-term drying were studied from the sediment cores of Lake Aerodrome, Gastropod Lake, and Prado Lake in Western Australia.

The pollen of the region revealed a tropical past that had signs of moisture and hinted at the dramatic shift to arid climates from tectonic drifts. Lake Izabal in Guatemala reflected the sediment record of natural climate variation and the land use impact by humans. This revealed insights into the rise and fall of the Maya civilization, as the pollen from opportunistic crops led to the dramatic decline of pollen from trees. This hinted at a worldwide deforestation, which subsequently led to the decline of political centers in the region. The pollen reemerged after the population eased and showed how the environment reacted to human activities and the formation of societies.

The modern pollen of Australia was more resistant to environmental stress, unlike its past, and showed that present pollen also carried hints of nature. The adaptation to survive a shift in climate revealed that modern pollen changed in its aspects based on the weather changes. The warmer the climate, the more changes occurred in the behavior of pollen-producing plants. The pollen season started earlier and remained for longer in the U.S. temperate regions due to warm temperatures and rising carbon dioxide. The changes from vehicles, factories, and other human activities were recorded in the fossil pollen record in the sediment layers of lakes across the world.