5 Myths About Oceans and Why You Should Care

As the 47th Earth Day prompted us to reflect on the ground beneath our feet and the flora and fauna whose lives are entwined with ours, it's worth giving equal consideration to the vast oceans just beyond our shores. The high seas are as vital to life on Earth as terra firma, and with their hugeness and depth, they provide that much more room for myths and mysteries. Here are five of the most persistent.Myth No. 1: Coastlines mark clear boundaries between land and sea.In a book on landforms and disasters, two scientists call shorelines the "most conspicuous boundary on Earth." Writing about Toronto's relationship with the sea, author M. Jane Fairburn notes that the name of the shore town Scarborough is apt, as the word "scar" is related to the Saxon word "sciran," meaning "to divide" and "the shore divides the land from the water." This is certainly how maps are drawn, too: The land ends and the ocean begins.But the distinction isn't really that clear. Every few seconds, waves move the edge of the sea in and out. In six-hour cycles, the pull of the moon shifts the level of the water. The combination of waves and tides means the edge of the sea is dynamic, depending on the moon, the wind and the steepness of the shore, which itself changes over time due to erosion.This movement creates an area of mingled land and sea where certain species thrive in a half-shore, half-ocean zone. Mangroves are some of the only trees that can grow in sea water, some by secreting salt crystals through their leaves to rid themselves of saline. They expand from soil into the shallows as they grow, trapping sediment and creating new land. Marsh grasses do the same, helped by animals that live among their roots and fertilize them. Corals are probably the most stubborn of this group of in-betweeners: They live around mountainous islands, and as the mountains sink under the sea, the corals keep growing toward the surface. Eventually the mountains disappear, leaving only a ring of coral called an atoll: neither land nor sea, but a space in between.  Continue reading...

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