In northwestern Newfoundland you can see first-hand an amazing relic of early life: thrombolites. Thrombolites are very rare microbial communities that lived in clusters, primarily during the Cambrian and Ordovician Periods (until 444 million years ago), made up of unicellular cyanobacteria, some of the very earliest life forms. In Flower’s Cove, Newfoundland, you’ll see fossilized thrombolites dating to 650 million years ago! That’s almost ten times the duration from dinosaur extinction to the present.
In the beginning, the Earth’s atmosphere had no oxygen, a strange and foreign thought nowadays when we take breathing for granted. We don’t even think about breathing. We just do it. Thankfully, as early as 3.5 billion years ago, the emergence of cyanobacteria and their ability to photosynthesize (get their energy to live from the sun and assimilate carbon dioxide) led to the start of the oxygenation of the atmosphere. For billions of years, life didn’t do a whole lot on earth, as these little organisms were umping out oxygen. But that oxygen was crucial for all later development. Descendants of these creatures are plentiful today. Cyanobacteria are a frequent menace in eutrophic waters that have excess nutrients, causing harmful algal blooms. They can also be found in many other locations throughout earth in present day, and cyanobacteria remain abundant and diverse.
Many people are familiar with the stromatolites of Shark Bay Australia, which are similar life forms but are modern day occurrences. There are several places on Earth that host living stromatolites, but the fossils of the earliest communities are very rare because of the long time that has elapsed, and many subduction events, glacial advances, volcanic events, and other rock-destroying events have occurred over the hundreds of millions of years, leaving just very few examples. As a result, they can be found in only a very small number of places in the world, including Newfoundland. The other place is in Australia. In Newfoundland, fossilized remains exist from Port au Port in the south to the northern part of the western peninsula, however by far the best place to see them is the small village of Flowers Cove. The site is located off route 430, and is hard to miss if you are driving the route. It makes a good and fascinating stop. A short walk on gravel and boardwalk trail, with interpretive signs, leads you around the site. As you visit the site, stop to appreciate their importance for the development of later life, as they provided the oxygen necessary for life to proliferate as we know it.
Lamoille Valley Rail Trail, Vermont