Cumberland Times-News

Columns

November 30, 2013

What life is found on the deep ocean floor?

I recently purchased “Oceans: A Visual Guide” by S. Hutchinson and L. E. Hawkins. “Oceans” is a Firefly book, published in 2008 with ISBN 13-978-1-55407-427-3 (paperback).

What I found most fascinating were the ghastly appearances and dynamics of the deep sea creatures that dwell in the darkness (living deeper than 300 meters or 1,000 feet).

The only light that breaks the blackness is the light emitted by the creatures themselves that live in or below this level. There is little mixing between the surface levels and the depths below.

Because water is densest at 4 C or 39 F, this is the temperature of the deep ocean. The pressures are enormous; roughly, for every 10 meters below the ocean surface, there is an increase of 1 atmosphere or 14.7 pounds per square inch.

So at 1,000 meters below, the pressure is 100 times our air pressure or 1,470 pounds per inch. The oceans’ floors average 4,000 meters or 2.5 miles in depth; here the pressure is 400 atmospheres or nearly 6,000 pounds per square inch!

How can any organism withstand such great pressures? At each level of the ocean, the external pressure on a life form equals its internal pressure outward.

But creatures living far below the ocean’s surface have their processes adapted to these pressures; if they are brought to the lower levels (for example, put in a fish tank), they will not survive.

The key reality is that most of the food for deep sea creatures is washed from the land or from the near surface layers of the oceans.

The deeper the level, the smaller the amount of plant and animal debris that descends from the upper layers of the ocean. Predators such as sharks also contribute to this rain of materials.

The total amount of organic carbon formed near the oceans’ surface by plants is 36 billion tons each year. Only 24 per cent of this material reaches the 1,000 meter (3,280 feet) level.

Less than 1 per cent of this material reaches the abyssal plains or ocean floors at 4,000 meters or 2.5 miles down. This rain is thicker at the equator and thinner in far north or far south latitudes.

Who lives on the ocean floor? The deep sea crustaceans (includes crabs, lobsters and shrimp) are stone crabs and the goblin or armored shrimp, both about a few inches across.

Deep sea squid may be quite small (about an inch across) or large (60 feet long).

Many deep sea squid are bioluminescent with light emitting organs on their bodies. Squids have eyes very similar to our own eyes but are much more sensitive owing to the very low light environment.

Most deep sea fishes are only a few inches in size. These fishes belong to primitive groups such as sharks, eels and bony fishes.

Bristlemouths are the most numerous fish in the oceans, living between 330 and 2,500 feet down. The hacketfishes dwell between 500 and 4,000 feet down; they have eyes that are up to 30 times more sensitive than human eyes.

Deep sea worms can be up to 6 feet long. Nematodes may represent from 50 t0 90 per cent of the live weight of animals in deep sea sediments.

There may be millions of species of nematodes. Deep sea cucumbers are estimated to be 95 per cent of the total biomass of animals over large part of the deep sea floor.

The deep sea floor has an area that is 41 per cent of the world’s oceans, an area comparable to the Earth’s land area. This floor is covered by soft, fine sediments accumulated over millions of years.

Just off the continental shelves, there is 200 grams of organisms per square meter. In the deep ocean floors, there is only 1 gram per square meter. The restricted food and low temperature cause the deep sea life forms to grow very slowly.

SKY SIGHTS AHEAD:  If Comet ISON survives its close passage by the sun late Nov. 28), it may be a conspicuous object in the 6:30 a.m. eastern dawn tomorrow morning.

It’s at low altitude (a few degrees) so you need to observe it from a place with a flat eastern horizon. Binoculars will be helpful in spotting the bright center or coma from which the fainter tail sprouts upward, pointing away from the sun.

Bob Doyle invites any readers comments and questions. E-mail him at rdoyle@frostburg.edu . He is available as a speaker on his column topics.

1
Text Only
Columns
  • Restore them Restore them

    There are an estimated 47,000 deceased veterans whose remains are unidentified and unclaimed throughout the U.S. A group of senators and congressmen hope to do something to
    bring these men and women some dignity after death.

    April 20, 2014 1 Photo

  • Happy Easter

    For the world’s more than 2 billion Christians, Easter is the day that defines their faith.
    The exact date of Christ’s resurrection is unknown, and even the precise locations of his crucifixion and burial are uncertain. This hasn’t stopped some people from saying they know the answer to these questions and others from trying to find out for themselves, or simply arguing about it.
     

    April 20, 2014

  • Odds are good that you didn’t know this

    Odds or Probabilities fascinate many people. There is a special website called www.BookOfOdds.com and an accompanying location on Facebook at /BookofOdds .This website lists 400,000 odds. Three of the people who are involved in this media display have coauthored a book, “The Book of Odds” that presents some of key odds, drawing from polls and statistics published in journals. The authors are A. Shapiro, L.F. Campbell and R. Wright. This paperback was published this year by Harper Collins with ISBN 978-0-06-206085-3.

    April 20, 2014

  • Trivial questions you don’t have to answer

    Every so often in this life, my mind, all on its own, generates questions that have no real answers. So I have decided to pass them on to you. I’m tired of them. If you come up with any answers, let me know. Remember when TV jealously guarded the time zone before 9 p.m. for wholesome shows that children could watch. My gosh, how many years ago was that? It seems like another world nowadays, when you can see murders, torture and rape, or those implied, every hour on the hour, somewhere on your public screen. It might be comforting then, to remember that most children nowadays are glued to their little machines with whole different worlds on them, that they can access all day long. Except that in these different worlds they also can view murders, torture and rape on demand.

    April 20, 2014

  • Think it’s not a small world? You’re wrong

    Yes, you read that right in the paper a couple of weeks ago. I covered a wedding as a newspaper reporter. I’ve retired from doing regular stories because my primary duties lie elsewhere, and I don’t have the time or mental energy for it. But I agreed to do it for a couple of reasons, one of which goes back more than 40 years. The former proprietor of The Famous North End Tavern told me about a wedding that was to take place at the Lions Center for Rehabilitation and Extended Care, where his wife works.

    April 20, 2014

  • No Bambi for you, Mrs. Doe

    Some people want so badly for deer birth control to work that they actually think it will, even on wild populations.
    I wish I had a couple bridges to sell.
    A week ago on the Outdoors page we ran the deer there do what deer  everywhere do. They eat the easiest food available such as gardens and ornamental plantings. They walk in front of moving cars. They give ticks and  parasites a place to live.

    April 19, 2014

  • We concur We concur

    We’re certain that Donald Rumsfeld, who served as Secretary of Defense under Presidents Gerald Ford and George W. Bush, echoes what many Americans feel about the complexity of filing income tax returns.
    When he filed his return, Rumsfeld sent the following letter to the Internal Revenue Service:

    April 16, 2014 1 Photo

  • Library week

    Public libraries remain one of the best uses of taxpayer dollars. They are open to all. Young or old, poor or wealthy, residents can use computers and read current magazines and newspapers. Compact discs featuring a wide variety of music and
    movies on DVD may be checked out in addition to novels and other books.

    April 13, 2014

  • Terps need to move and move quickly

    The good news is Maryland will never have to play another basketball game in the Atlantic Coast Conference. Goodbye, good riddance, sayonara, smell ya, no more of you, stay classy, we won’t let the door hit us on the way out.
    Until we see you in court.

    April 13, 2014

  • Sunday hunting Sunday hunting

    Legislation that increases hunting oppportunities on Sundays in Garrett, Allegany and Washington counties has passed the Maryland General Assembly and reached the governor’s desk.

    April 13, 2014 1 Photo