Surviving the Ice Age
Through the history of the earth there have been many Ice Ages and mini-Ice Ages. Going back in time before men began spreading from Africa to Europe and beyond, various research teams around the globe have found the first direct evidence that glacial meltwater provided a crucial lifeline to eukaryotes during Snowball Earth, when the oceans were cut off from life-giving oxygen, answering a question puzzling scientist for years.
In a new study published in the Proceedings of the National Academy of Sciences, researchers studied iron-rich rocks left behind by glacial deposits in Australia, Namibia, and California to get a window into the environmental conditions during the ice age. Using geological maps and clues from locals, they hiked to rock outcrops, navigating challenging trails to track down the rock formations.
By examining the chemistry of the iron formations in these rocks, the researchers were able to estimate the amount of oxygen in the oceans around 700 million years ago and better understand the effects this would have had on all oxygen-dependent marine life, including the earliest animals like simple sponges.
The evidence suggests that although much of the oceans during the deep freeze would have been uninhabitable due to a lack of oxygen, in areas where the grounded ice sheet begins to float there was a critical supply of oxygenated meltwater.
Around 700 million years ago, the Earth experienced the most severe ice age of its history, threatening the survival of much of the planet’s life. Previous research has suggested that oxygen-dependent life may have been restricted to meltwater puddles on the surface of the ice, but this study provides new evidence of oxygenated marine environments.
While the findings focus on the availability of oxygen, primitive eukaryotes would also have needed food to survive the harsh conditions of the ice age. Further research is needed to explore how these environments might have sustained a food web. A starting point might be modern ice environments that host complex ecosystems today.
The most recent Ice Age that created the last glaciation in Europe, about 20,000 to 70,000 years before present led to the northern Europe glaciation, called Weichselian Glaciation and in the Alpine Region Würm Glaciation. This Ice Age would have had a dramatic affect upon the development of the Cro-Magnum species and the demise of the Neanderthals.
