Bahamanian Stromatolites These giant boulders are stromatolites, one of the oldest types of life rep

Bahamanian StromatolitesThese giant boulders are stromatolites, one of the oldest types of life represented on Earth. Communities of microorganisms living in distinct layers interact with each other and build these structures outwards over time. Layers of carbonate mud either precipitate from the ocean or simply flow past and stick to the outer layers, causing the rocky mixture to grow outwards over time.Stromatolites are represented in the fossil record going back at least 3 billion years, maybe longer (some layered sediments older than that may be stromatolites as well). Cyanobacteria living in these communities were major contributors to the rise of oxygen in Earth’s atmosphere, which started about 2.5 billion years ago.Although they have lived for billions of years, live stromatolites are uncommon on Earth today as the organisms can easily be food sources for more complex predatory animals. To survive today, stromatolites need an environment where the surroundings limit the threat from predators. Here in the Bahamas, the stromatolites are commonly buried by sediment that protects them for a portion of the year, keeping predators and other organisms that could occupy this area from gaining a foothold.-JBBImage credit: Sean Nashhttps://flic.kr/p/bLze3pReferences:http://bit.ly/1QDcMiyhttp://www.bahamas.com/vendor/stromatolites-exumashttp://link.springer.com/article/10.1007%2FBF02537442 -- source link

More pics about