If you have no idea what an abyssal plain is, your imagination is likely to come up with some depressing images (‘abyssal’ sounds pretty close to ‘abysmal,’ after all).
Here you will learn what an abyssal plain actually is, what it looks like and what lives there.
What is an Abyssal Plain?
Abyssal plain? It sounds like a combination of the words ‘abyss’ and ‘dismal.’ And those two words might not be that far off when describing an abyssal plain. If you’ve ever thought the word ‘abyss’ reminded you of the depths of the ocean, you’re on the right track. And the word ‘plain’ usually means a flat, wide area. Put those two things together and you have an abyssal plain, which refers to the huge, flat areas on the ocean floor.Flat is almost an understatement.
The abyssal plains are some of the flattest features on the planet. Some drop in elevation less than a foot for every 1,000 feet in distance. Sometimes there are small hills called abyssal hills, but generally abyssal plains are as flat as a tabletop. Abyssal plains are 2,200 to 5,500 feet below ocean surface and are between the continental rise (the part of the underwater continental margin farthest from the shore) and the mid-ocean ridge (where under-ocean tectonic plates move away from each other, forming volcanoes that turn into underwater mountain ranges) or ocean trenches (where one tectonic plate slides beneath another, in a process called subduction).
What do Abyssal Plains Look Like?
There’s more to abyssal plains than just being flat. They are covered in sediment, which is part of the reason they are so featureless.
The sediments are brought by ocean currents and by an assortment of debris that rains from above. The sediment includes everything from volcanic ash, dust, organic matter from ocean creatures, nodules made from a mixture of maganese and other minerals, and even bits of meteorites. The rate that sediments accumulate on the abyssal plains make ‘glacial speeds’ look fast.
The sediments stack up only one inch every thousand years.;Abyssal plains cover more area in the Atlantic and Indian Oceans and less of the Pacific Ocean. Worldwide though, abyssal plains account for 40% of the world’s ocean floors.
Life on the Abyssal Plains
Animal and plant life isn’t exactly abundant on the abyssal plains, but you might be surprised at what is there and how it survives. Things like sea cucumbers, sea urchins, sediment microbes, and even sci-fi-like creatures such as grenadier fish all make their home on the abyssal plains. What life is there depends on the organic matter raining down through the water above.
That includes fecal matter and body parts from other sea organisms. Scientists recently figured out that increases in populations of sea creatures and algae near the surface can provide years worth of food for the creatures of the abyssal plains. The algae blooms and population booms of sea animals are a real boon for the creatures of the abyssal plains.
Abyssal plains are large, flat areas, usually between the continental rise and the mid-ocean ridges or ocean trenches below the ocean surface. Abyssal plains are quite deep under the surface and are covered in sediments. Sediments accumulate very slowly and come from ocean currents and things that rain down from above, including dust, volcanic ash, minerals, organic matter from animals and plants, and even meteorites. The organic matter supports the animals and microbes that live on the abyssal plain.
Abyssal plains cover 40% of the ocean floor.