Countless lakes in Canada and elsewhere may offer some important insights into how life on Earth began and may also help us grapple with the pressing environmental issues facing the planet today.
The Boreal Shield is the the largest of Canada’s 15 terrestrial ecozones, where boreal forests overlap the Canadian Shield. It stretches almost 4,000 kilometres from Newfoundland to Alberta. The millions of lakes that stud the Boreal Shield may offer clues into how ancient microorganisms might have shaped atmospheric and geological conditions on Earth.
We’ve long been fascinated by how life on Earth began. From an evolutionary perspective, we can trace our origins back billions of years to single-celled microorganisms in the ocean.
The conditions of this early Earth ocean of the Archaean Eon, more than 2.5 billion years ago, were very different from ocean conditions today. The oceans lacked oxygen and were high in iron; many now speculate that ancient bacteria might have eked out an existence on a mixture of iron-rich chemicals and light energy.
One way to investigate the mysteries of Earth’s origins is to look for modern-day equivalents of these ancient oceans and examine their chemical processes and biological diversity. The challenge, however, is that modern equivalents of ancient oceans are extremely rare.
Lake Matano in Indonesia is an example of one such modern equivalent. It’s an iron-rich lake that has permanently oxygen-free bottom waters. These bottom waters are sufficiently deep and wind-protected that they do not mix with surface waters throughout the year.
In Lake Matano, and a select few other lakes discovered in recent years, specific species of “green sulfur bacteria” are thought to thrive by using light energy to support a metabolism based on dissolved iron.
Could these bacteria represent modern-day equivalents of the earliest metabolisms on Earth? Did similar ancestors of these bacteria shape our biosphere to help support the evolution of additional life forms? What other microorganisms and metabolisms associate with these species? Could these too represent the earliest processes on the planet?
Oxygen and green sulfur bacteria
The Lake Matano discoveries had special significance for Dr. Sherry Schiff in the Department of Earth and Environmental Sciences at the University of Waterloo. Her long history of studying freshwater habitats, including those at the International Institute for Sustainable Development — Experimental Lakes Area (IISD-ELA) in northern Ontario, helped her formulate a hypothesis.
Modern equivalents of the early Earth ocean are anoxic, iron-rich and sulfur-poor. Millions of Boreal Shield lakes come very close to these conditions.
The problem is oxygen.
Many of the Boreal Shield lakes in Canada, and boreal lakes across Europe and Russia, are high in iron and low in sulfur, yet exposed to oxygen at most depths at least twice a year, when the lake surface waters mix with deeper waters. If the green sulfur bacteria return following exposure to oxygen, then Dr. Schiff predicted that millions of Boreal Shield lakes could harbour microbial communities analogous to those of Earth in its infancy.
And if IISD-ELA lakes were among these examples, then many of these Canadian lakes could be manipulated experimentally for further study.
In order to test these predictions, Dr. Schiff assembled a team of Earth scientists, limnologists (freshwater scientists) and microbiologists.
The Earth scientists looked at the chemical composition of representative IISD-ELA lakes at varying depths and at different times, and the microbiologists, led by Jackson Tsuji in Dr. Josh Neufeld’s lab, helped generate a census of microbes in these same samples by analyzing extracted DNA.
The chemical data indicated that an iron-based metabolism, energized by light, was likely. The DNA data confirmed that species of green sulfur bacteria almost identical to those in Lake Matano became abundant when oxygen was depleted in the lakes.
Implications for human health
In addition to providing a unique opportunity to study Canadian Boreal Shield lakes as examples of the oceans of early Earth, this important new discovery has potential implications for environmental issues today.
The occurrence and severity of toxic blooms of cyanobacteria may be tightly linked to the availability of iron. In addition, microbial metabolism of iron may well be linked to the metabolism of other compounds of interest, including phosphorous, mercury and the potent greenhouse gas, methane. Each of these compounds has major implications for our climate, aquatic systems and for human health.
The discovery that millions of Boreal Shield lakes are potential examples of early Earth oceans was not a predictable outcome of the original research initiative. That the researchers had the flexibility and funding to pursue some unexpected results that lead to this crucial interdisciplinary research was fundamental to their success.
The results have broad implications for our understanding of early Earth origins, including the origins of life on the planet, in addition to modern-day relevance. All of it underlines how basic research can lead to unexpected discoveries.
Future research by the Schiff and Neufeld labs, as well as collaborators at Wilfrid Laurier University, the University of Toronto and the IISD-ELA, will explore the links between Boreal Shield lakes, cyanobacteria, methane, phosphorous and iron.
At this point there are more questions than answers, but that’s how science works.
Josh D. Neufeld, Professor, University of Waterloo; Jackson Tsuji, PhD student, Neufeld Research Group, University of Waterloo, and Sherry Schiff, Professor, Environmental Geochemistry, University of Waterloo
Research from the University of Edinburgh deciphers a translated tablet known as the “Vulture Stone”. Dated back to 10,950 BCE – based on it’s self stamped date – the tablet seems to depict a flurry of monumental comet impacts.
The temple in question, found in Turkey, Göbekli Tepe, is a 13,000 year old site that was traditionally interpreted as a sanctuary, place of worship for the dead, or possibly an ancient form of observatory. Perched atop a mountain ridge, the observatory theory seems the most logical.
“It appears Gobekli Tepe was, among other things, an observatory for monitoring the night sky,”
The carvings found on the Vulture Stone show different animals in specific positions around the stone and date to an event roughly 2,000 years before the 10,950 BCE impact. The symbols had long been a mystery to researchers until Martin Sweatman and team were able to decipher corespondances with the symbols and ancient astronomical positioning.
When the theoretical data was cross-checked with computer simulations of the Solar System around that time, records show that the tablets information could correspond with a comet impact that occurred in 10,950 BCE. That impact triggered a mini ice age that started a significant change in the evolution of the Earth. The Ice Age known as the Younger Dryas, lasted around 1,000 years and was considered significant as it was near this time that the first Neolithic civilisations came into being. The Younger Dryas is also famously referred to as the period in which the wooly mammoth became extinct.
Ancient civilizations had a remarkable ability to document stellar phenomena. Here’s what research suggests the sky would have looked like at that time:
Carbon dating from the tablet shows that the suspected timing of the artifact is correct, give or take 250 years from 10,950 BCE (plus or minus).
According to Sweatman, this isn’t the first time ancient archaeology has provided insight into civilisation’s past.
“Many paleolithic cave paintings and artefacts with similar animal symbols and other repeated symbols suggest astronomy could be very ancient indeed,” he told The Telegraph.
WASHINGTON (Reuters) – Microfossils up to almost 4.3 billion years old found in Canada of microbes are similar to the bacteria that thrive today around sea floor hydrothermal vents and may represent the oldest-known evidence of life on Earth, scientists said on Wednesday.
The fossils from the Hudson Bay shoreline in northern Quebec near the Nastapoka Islands lend credence to the hypothesis that hydrothermal vents spewing hot water may have been the cradle of life on Earth relatively soon after the planet formed, the researchers said.
They also said Earth’s planetary neighbor Mars at that time is thought to have had oceans, long since gone, that may have boasted similar conditions conducive to the advent of life.
Tiny filaments and tubes made of a form of iron oxide, or rust, formed by the microbes were found encased in layers of quartz that experts have determined to be between 3.77 billion and 4.28 billion years old, according to the study published in the journal Nature.
The researchers expressed confidence the fossils from northeastern Canada were formed by organisms, saying no non-biological explanation was plausible.
It was primordial microbes like those described in the study that set in motion the evolutionary march toward complex life and, eventually, the appearance of humans 200,000 years ago.
“Understanding how and when life began on Earth helps answer the long-standing questions: Where do we come from? Is there life elsewhere in the universe?” said study researcher Matthew Dodd, a University College London biogeochemist.
The scientists said the primordial microbes’ structure closely resembled modern bacteria that dwell near iron-rich hydrothermal vents. They believe that, like their modern counterparts, they were iron-eaters. The rock’s composition was consistent with a deep-sea vent environment.
“This is important for the origin of life,” said study researcher Dominic Papineau, a University College London astrobiologist. “It shows microbial life diversified to specialized microbes very early in Earth history.
“It is also important for the evolution of life. It shows that some microbes have not changed significantly” since Earth’s early times, Papineau said.
Earth formed about 4.5 billion years ago and the oceans appeared about 4.4 billion years ago. If the fossils are indeed 4.28 billion years old, that would suggest “an almost instantaneous emergence of life” after ocean formation, Dodd said.
The fossils appear to be older than any other previously discovered evidence of life. For example, other scientists last year described 3.7 billion-year-old fossilized microbial mats, called stromatolites, from Greenland.
(Reporting by Will Dunham; Editing by Bill Trott)
Our next supercontinent is called Amasia, and it’s expected to fully form 50-200 million years from now.
If you look at a map, you may notice that continents look like they fit together like puzzle pieces. And that’s because they do; roughly 400 million years ago our continents formed one massive land mass known as Pangea. Today’s most prominent remnant of the supercontinent is Brazil’s bulge which seems like it’s locking into West Africa’s dimple.
Using powerful computer programs researchers from around the world are piecing together long lost worlds and future land masses such as Amasia, our potential next supercontinent.
An article in ScienceNews explores the concept and consults researchers on the idea of continental drift. There’s little doubt that our continents our moving, but there is speculation about what the future of our planet may look like.
“Speculation about the future supercontinent Amasia is exactly that, speculation. But there’s hard science behind the conjecture.” says geologist Ross Mitchell of Curtin University in Perth, Australia. In a paper in the September Geology, Yoshida describes how North America, Eurasia, Australia and Africa will end up merged in the Northern Hemisphere.
Head over to the original article at ScienceNews to find an interactive timeline of the Earth’s continental shift.