The ocean floor is home to many unique communities of plants and animals. Most of these marine ecosystems are near the water surface, such as the Great Barrier Reef, a 2,000-km-long coral formation off the northeastern coast of Australia. Coral reefs, like nearly all complex living communities, depend on solar energy for growth (photosynthesis). The sun's energy, however, penetrates at most only about 300 m below the surface of the water. The relatively shallow penetration of solar energy and the sinking of cold, subpolar water combine to make most of the deep ocean floor a frigid environment with few life forms.In 1977, scientists discovered hot springs at a depth of 2.5 km, on the Galapagos Rift off the coast of Ecuador. This exciting discovery was not really a surprise. Since the early 1970s, scientists had predicted that hot springs should be found at the active spreading centers along the mid-oceanic ridges, where magma, at temperatures over 1,000 °C, presumably was being erupted to form new oceanic crust. More exciting, because it was totally unexpected, was the discovery of abundant and unusual sea life giant tube worms, huge clams, and mussels that thrived around the hot springs. Since 1977, other hot springs and associated sea life have been found at a number of sites along the mid-oceanic ridges, many on the East Pacific Rise. The waters around these deep-ocean hot springs, which can be as hot as 380 °C, are home to a unique ecosystem.
Many species of deep ocean fish have special adaptations to living in extremely high pressure, low light conditions. Viper fish are some of the most wicked looking fish dredged up from the depths. Some of them are black as night all over with light organs in strategic places on their bodies, including one on a long dorsal fin that serves as a lure for the fish it preys upon. Some viperfish don't have any pigment at all, they're "see through". They also have enlarged eyes, presumably for gathering as much light as possible where there is little or no light at all. The light organs create lights by using a chemical process called bioluminescence. Other deep ocean fish, such as the the gulper eel.
The world's record holder for deepest fish goes to the brotulid family, about which scientists know almost nothing. These fish are benthopelagic, living at depths of 7000 meters or more. The world's deepest fish was found in the Puerto Rican Trench at a depth of 8,372 meters. Their eyes appear to be virtually nonexistent. Maybe it's because there is never enough light for the fish to see, so why bother with the eyes? After all, eyes in most organisms are designed for gathering light in the creature's visual field and transmitting it to the brain giving it useful information about its environment. In a world where no sunlight ever penetrates there's probably little use for eyes. The brotulids probably have other, highly developed senses to compensate for their lack of vision, which help them to find their way around in the dark depths.
These creatures live on or just underneath the surface of the very bottom of the ocean, on the abyssal plain. Called "sea pigs", they are a type of sea cucumber, which is a member of the same phylum as starfish and sea urchins. They look and act kind of like slugs do up here on land. They feed on the mud of the sea floor, benefiting from the organic materials that settle to the ocean bottom. Sea cucumbers, starfish and sea urchins can be found in all depths of the ocean. For reasons scientists don't yet understand, members of the phylum Echinodermata are extremely successful down in the ocean depths. They are the most plentiful species of sea creature down there.
Wednesday, April 30, 2008
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6 comments:
Awesome post Nick! You really covered alot of information about the deep oceans. I liked your last paragraph...the "sea pigs" were very interesting. Keep us the mind boggling work.
Jake
Great information! You definitely had many things in there that I hadn't read about! I agree with JB, the sea pigs thing was very interesting. You have a good diversity of facts.
Fabuluously yours,
Megan
nice info nick! all of your facts were really in depth and informative! like jake said, the "sea pigs" were definitely mind boggling :) keep up the good work!
SarahAnn
Nick,
You did a wonderful job on your post this week. It was extremely elaborate and you included a large variety of information. Your post was very unique and provided information that many posts did not. Your writing style was very matter of fact and was almost like reading from a text book. I really enjoyed your post and I think it was your best post yet!
~Lindsey~
You had me at hello. nice job on the post. really put some effort into that.
-Dustin
You posting is very informative. You get into a lot of detail. Almost too much for such a short summary. Next time, you might want to choose less topics and go into a little deeper depth on the topic. All-in-all, very enjoyable to read.
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