Name: Deep Oceans - Abyssal Plains, Trenches and their Bizarre Life - Biomes#12
Uploaded: 2021-12-02T16:00:33+00:00
Duration: 20 min 48 s
Description: Oceanography - the nature of the vast oceans and their ecosystems. The largest of the world's biomes is the one we know the least of. Crushing pressures and the vast extent of the abyssal plains of th

2 years ago

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Oceanography - the nature of the vast oceans and their ecosystems. The largest of the world's biomes is the one we know the least of. Crushing pressures and the vast extent of the abyssal plains of the oceans mean we know more about the surface of the moon than the depths below the water. What we do know, however, is life here has evolved into an almost alien-like form that differs greatly from that of the surface. Join me in this final episode of the Biomes series, as I investigate the nature of the deep oceans and their bizarre ecosystems.

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🕐TIMESTAMPS🕖
👉0:00 Opening Montage
👉0:30 Introduction and Titles
👉1:52 A Biome of Total Darkness
👉3:10 Abyssal Plains / Deep Ocean Trenches
👉4:42 Ocean Currents / Thermohaline Circulation
👉7:48 Ocean Temperatures / Thermocline
👉9:11 Lifeforms of the Deep Ocean
👉14:10 Hydrothermal Vents / Chemosynthesis
👉15:46 In Closing
👉16:17 BIOMES SERIES CLOSING MONTAGE

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The average depth of the oceans is about 4000m, where no light reaches, and a cold, still world exists, totally dependent upon organic debris falling from above to provide food for its strange inhabitants. After descending from the continental shelf via the continental slope, most of the ocean floor is in the form of abyssal plains. However, mid-ocean ridges, where new crust forms, are at shallower depths, while deep ocean trenches descend to as much as 11000m, where pressures can reach 1100 atmospheres or 16000 psi.

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The vast flat surface of the oceans act as generators for the world's weather, and storms that form over the ocean in specific regular places lead to the formation of ocean currents that in turn shape global climate patterns, such as the Gulf Stream warming Europe, or the Peru Current creating the Atacama Desert. These surface currents are augmented by an even more complex conveyer belt of deep ocean currents that can be traced all around the world in what is known as the Thermohaline Circulation.

But in general the deep ocean is very still and cold, since cold water sits below warm surface water. The temperature of the water plummets suddenly at around 500m in depth in what is called the Thermocline.

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In the absence of light, there are no plants, so most of the biomass in the deep sea is in the form of animals - fish, crustaceans, cephalopods such as squid and octopus, starfish and adventurous mammals - the whales. Many of these creatures use bioluminescence to lure a mate or prey. Gigantism is also a feature of many of the animals here, with crabs and squid, for instance, being much larger than their surface water cousins.

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At mid-ocean ridges are found chemically rich hydrothermal vents that allow bacteria to build organic matter from. In turn these bacteria act as symbiotes for tube worms and other life that provides the only biome on our planet that is not dependent upon photosynthesis.

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