MARINE

The marine environment makes up virtually two-thirds of the surface of the earth. The oceans have been around for about 3.8 billion years. During much of this time there has been very little land, and what land there was has been moving around, breaking into continents and islands, merging together, and then breaking up again.

About 2.3-2.5 billion years ago, the first oxygen producing photosynthetic organisms living within the seas were the blue-green algae (more properly – the cyanobacteria) giving what’s called ‘The Great Oxygenation Event’. While they did produce enough oxygen to change the atmosphere, they didn’t produce sufficient quantities for other aerobic organisms to develop for nearly another 2 billion years. It wasn’t until about 850 million years ago that free oxygen started increasing. And it was about 550 million years ago that nearly all the phyla of animals began to appear giving what’s called ‘The Cambrian Explosion’.

However, over these last 550 million years the oceans now contain thousands of spectacular fishes, molluscs (clams and the like), invertebrates (anemones, octopuses, and the like), whales, and so much more.

This section – The Oceans, will be an ongoing discourse of Oceanography, Marine Biology, Maritime History, SCUBA and Skin Diving, Sailing, …

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