The Amazing Ocean
The Facts of Life Under the Sea
Story by Alex
Brylske Photos by Norbert Wu
A well-known Chinese
proverb maintains that a picture is worth a thousand words. That’s especially
true in a world where we’re bombarded with information, where data is amassed
at a rate boggling the minds of those of us who learned math on slide rulers.
It seems that anything that can help us “cut to the chase” is not only
appreciated, but often the only way we can get a message across. The famous
KISS principle — “keep it simple, stupid” — should perhaps be revised to “keep
it simple and succinct, stupid” but I suspect there might be a few concerns
over the new acronym.
In our quest for brevity, even facts are sometimes too much
to process. In order to make a point, we often render knowledge down to its
essence, much like boiling a chicken for soup stock. These snippets of
knowledge can be very powerful tools for describing the sum and substance of a
concept or relating its true state. I was reminded of the power of simplicity
as I was preparing to write this article on the plight of the world’s oceans.
As many of you realize (I hope), to bring the troubled state
of the aquatic realm to the fore, this year has been designated by the United
Nations and others as the International Year of the Ocean. As I researched this
story it occurred to me that the best way to make a point might not be to try
to bring any focus, elaboration or opinion to bear, but merely let the facts
speak for themselves, like a great photograph — the Marines raising the flag on
Iwo Jima or the fireman carrying the child out of the rubble of the Oklahoma
City bombing. Interpretation can be a needless distraction at times.
What follows is merely a presentation of facts. Taken
individually, none probably has much substance. But when viewed in context and
in relation to one another, the story they relate is both fascinating and
alarming.
Ocean Facts
The oceans contain 99 percent of the living space on Earth,
covering over 71 percent of its surface. In all, the oceans contain 328 million
cubic miles/1.34 billion cu. km of water.
Ninety-seven percent of the water on Earth is sea water.
Less than 1 percent is fresh, while another 2 to 3 percent is contained in
glaciers and icecaps.
The surface area of the Pacific Ocean alone exceeds the
surface area of all land masses combined.
The record for the longest coastline goes to Canada, with
56,453 miles/ 90,906 km. That’s around 15 percent of the world’s total 372,384
miles/599,652 km of coastline.
Sea water contains almost every element on Earth. In fact,
if all the salt were extracted it could cover the continents to a depth of 5
feet/1.5 m. And if all the gold could be extracted, every man, woman and child
on Earth would have about 9 pounds/4 kg.
While the average land elevation is 2,755 feet/840 m, the
average depth of the ocean is 12,238 feet/3,730 m. The deepest part is the
Marianas Trench in an area called Challenger Deep, where it’s 35,802
feet/10,912 m to the bottom, a depth that could completely submerge Mount
Everest by more than 8,000 feet/2,438 m. The pressure at the bottom is an
astounding 8 tons per square inch. That’s like one person trying to support 50
jumbo jets.
Speaking of Mount Everest, if you thought it was the tallest
mountain on Earth, think again. Although Mount Everest is 29,028 feet/8,847 m,
when measured from the sea floor, Hawaii’s Mauna Kea is 33,465 feet/10,200 m.
(Only 13,796 feet/4,205 m stands above sea level, however.)
On the subject of mountains, the Earth’s longest range is —
where else? — underwater. It’s called the Mid-Ocean Ridge and winds its way
from the Arctic Ocean through the Atlantic, skirting Africa, Asia and
Australia, and crosses the Pacific to the west coast of North America. That’s
four times longer than the Andes, Rockies and Himalayas combined.
While land-based volcanic eruptions garner most of the
publicity, more than 90 percent of all volcanic activity occurs in the oceans.
Scientists have, in fact, located the largest known concentration of volcanoes
along the sea floor of the South Pacific in an area roughly the size of New
York state. The area contains over 1,100 volcanic cones and seamounts, two or
three of which could erupt at any time.
The Atlantic Ocean is still growing at a rate of 1.5
inches/4 cm per year. That means it was about 66 feet/20 m narrower when
Columbus landed.
If you think it’s cold where you dive, consider that the
average sea-water temperature is a bone-chilling 38˚F/3.5˚C. However, sea
surface temperatures in the Persian Gulf can reach over 96˚F/36˚C.
Most of us think of ocean currents as relatively permanent
features flowing in only one direction, but there is a notable exception. In
the Indian Ocean, currents are seasonal, driven by the monsoon winds. From
November to March the current is driven toward Africa, only to reverse
direction in May with the changing wind pattern.
The term “Arctic” is derived from the Greek arktos, meaning
bear. It was named for the polar bear, Ursus maritimas (sea bear). These
creatures are so adapted to life on the ice packs that some never set foot on
land.
The largest tidal wave (tsunami) ever recorded was 210
feet/64 m high. It struck Siberia’s Kamchatka Peninsula in 1737.
Life began in the seas sometime between 3.1 and 3.4 billion
years ago. But it didn’t move to land until about 400 million years ago,
proving that our connection to the sea is far older than to land. Two thirds of
the phyla, the major groupings of life on Earth, are exclusively or
predominantly found in the ocean.
The base of the marine food chain is the tiny, free-floating
organism called phytoplankton, on which almost all other life in the sea is
dependent. In fact, as they produce about 50 percent of our oxygen supply, all
life on Earth depends on these diminutive wanderers. They are so prolific that
each year 200 million tons of
phytoplankton grow in the world’s oceans. For comparison, that’s 10 times the
weight of the entire human population of our planet.
The blue whale, Balaenoptera musculus, is the largest known
animal ever to have lived on sea or land. Bigger than even the biggest
dinosaur, it can reach more than 110 feet/33 m in length and weigh more than 50
adult elephants. With a heart the size of a Volkswagen Beetle, the whale’s
blood vessels are so large that a full-grown trout could swim through them. To
sustain its bulk, the blue whale must consume up to 4 tons of krill per day.
Speaking of big, while most divers know that the largest
fish in the sea is the whale shark, less well-known is the largest bony fish.
(Shark are cartilaginous, remember.) The winner is the rarely seen ocean
sunfish, Mola mola, which can grow to over 10 feet/3 m and tip the scales at
over 2 tons.
On the opposite end of the size chart is the dwarf goby,
Eviota sp., of the Indian Ocean. As a full-grown adult it reaches a mere .35
inches/9 mm. The record for the smallest shark is the spined pygmy, Squaliolus
laticaudus, which measures a whopping 6 inches/15 cm.
If you think finding a date is tough, consider the plight of
some deep-sea fishes like the angler fish, Photocorymus hippurus. The male,
tiny in comparison to the female, attaches itself by biting his companion. Then
the two merge into one, with the male becoming nothing more than a small,
permanent appendage that fertilizes eggs.
Many divers are all too familiar with the highly potent
sting of the jellyfish — actually a siphonophore — called the Portuguese
man-of-war, Physalia physalis. The bluish saclike creature can extend its
powerful tentacles to depths of almost 100 feet/30 m. What you may not know is
that this critter isn’t a single organism at all. It’s actually a colony of as
many as 100,000 tiny individuals, each doing its own specialized job.
Few folks realize that a huge mat of sargassum — a type of
marine algae — the size of India floats permanently in the middle of the North
Atlantic. It’s held there solely by the circulation pattern of oceanic
currents, most notably the Gulf Stream. Aptly, it’s known as the Sargasso Sea.
It wasn’t until 1977 that scientists discovered an entirely
new basis for life on Earth — chemosynthesis. Hydrothermal vents which occur at
fractures along deep-sea oceanic plates spew sulfur compounds, which support
the only complex ecosystem known to run on chemicals rather than energy from
the sun. It is now hypothesized by some that this is where life on Earth began.
Stories of sea serpents may be true after all — except that
they’re not monsters, but rare fish. Such stories probably originated from
sightings of the oarfish, Regalecus glesne, which at 50 feet/15 m long is the
longest bony fish in the world.
The structure and chemistry of coral is so close to human
bone that coral is now sometimes used to repair or replace bone in humans.
There’s a good reason Atlantic horseshoe crabs, Limulus
polyphemus, look like they’re products of the special-effects department of
Jurassic Park. They have remained essentially unchanged for the past 135
million years. More importantly to humans, their blood is used to test for the
toxins that cause septic shock, a condition which at one time accounted for
half of all hospital-acquired infections and one-fifth of all hospital deaths.
Global fish production yields more than cattle, sheep,
poultry or eggs and is the biggest source of protein in the world. Yet in an
amazing example of Alice-in-Wonderland economics, the worldwide fishing
industry spends $124 billion per year to catch only $70 billion worth of fish.
This difference is made up by government subsidies.
Fully one-third of the total worldwide catch (27 million
metric tons) of commercial marine fisheries is discarded as “by-catch,” most of
which dies. This includes not only nontargeted fish, but seabirds, sea turtles
and marine mammals as well. The shrimp industry is even worse. Shrimp trawlers
discard 80 to 90 percent of their hauls, so for every pound of shrimp you eat,
more than 4 pounds/1.8 kg of fish are wastefully tossed overboard to die.
Weighing 1,500 pounds/679 kg and capable of swimming up to
55 miles/89 km per hour, Bluefin tuna, Thunnus thynnus, are among the largest
and fastest fishes. Unfortunately, they’re also in high demand at Japan’s sushi
bars. One fish can sell for over $25,000, placing an incredible and
unsustainable demand on the stock.
Ask most people what’s the No. 1 pollution problem facing
the ocean, and you’re likely to hear about oil spills. The fact is that of the
5 million tons of oil that enters the oceans each year, spills from tankers and
oil platforms account for only about 5 percent of the total. Twice that amount
comes from sewage treatment plants like the one down the street from you. Think
of that the next time you change your car’s oil and are tempted to pour the
waste down the drain.
As testament to the interrelatedness of the atmosphere and
ocean, fully one-third of toxic contaminants and excess nutrients entering the
ocean come from atmospheric deposition from rain and snow.
Serving as the drainage basin for almost 40 percent of the
continental United States, the Mississippi River carries so many excess
nutrients into the Gulf of Mexico that oxygen loss from algal blooms has
decimated all life within 4,000 square miles/10,363 sq. km of bottom area off
the coast of Louisiana and Texas. Scientists refer to this as the Gulf of
Mexico’s “Dead Zone.”
One of the most serious threats to marine ecosystems today
comes from hitchhikers. Various organisms, such as the zebra mussel, Dreissena
polymorpha, have been transported worldwide in the ballast water of ships.
These organisms often disrupt entire marine ecosystems. Not limited to
bivalves, exotic stowaways include fishes, plants, poisonous algae and even
diseases such as cholera.
If it seems crowded when you go to the beach, consider that
one-half of the world’s people live within 60 miles/97 km of the sea coast. And
it’s going to get worse. Within 30 years, a billion more people than are alive
today (6.5 billion) will be living along the coasts.
In case you think global warming isn’t a serious problem,
consider this: An increase of 7˚F/4˚C in the average global atmospheric
temperature would melt enough of the polar icecap to increase the sea level
some 230 feet/70 m. Virtually every coastal city in existence would be history.
Recently, I read a quote by Arthur C. Clarke, a longtime
ocean advocate and author of the classic novel 2001: A Space Odyssey, which
succinctly puts the issue of the world’s oceans into perspective. “It seems
odd,” he writes, “that we call our home planet Earth when it is clearly Ocean.”
How true.
Most of the facts in this article came from two outstanding
Web sources. For more information about the oceans and the problems facing
them, check out the Web site for the Smithsonian Institution’s Ocean Planet
exhibition, www.seawifs.gsfc.nasa.gov/ocean_planet.html and Seaweb
www.seaweb.org.
Caitlin will give non-divers the opportunity to observe underwater marine life. (Photo: Global Reef Record)
