Ocean trenchesĪfter scaling the mid-ocean ridge and traversing hundreds to thousands of miles of abyssal plains, you might encounter an ocean trench. Tracing their way around the global ocean, this system of underwater volcanoes forms the longest mountain range on Earth. Rising up from the abyssal plain, you would encounter the mid-ocean ridge, an underwater mountain range, over 40,000 miles long, rising to an average depth of 8,000 feet. They are interrupted by features like hills, valleys, and seamounts (underwater mountains that are also hotspots for biodiversity). But despite their name, these “plains” are not uniformly flat. Sunlight does not penetrate to the sea floor, making these deep, dark ecosystems less productive than those along the continental shelf. At depths of over 10,000 feet and covering 70% of the ocean floor, abyssal plains are the largest habitat on earth. Abyssal plainsĬontinuing your journey across the ocean basin, you would descend the steep continental slope to the abyssal plain.
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The waters along the continental shelf are usually productive, both from light and nutrients from upwelling and runoff. It is narrow or nearly nonexistent in some places in others, it extends for hundreds of miles.
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The continental shelf is an area of relatively shallow water, usually less than a few hundred feet deep, that surrounds land.
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Starting from land, a trip across an ocean basin along the seafloor would begin with crossing the continental shelf.