2. While there is only one global ocean, the vast body of water
that covers 71 percent of the Earth is geographically divided into
distinct named regions. The boundaries between these regions have
evolved over time for a variety of historical, cultural,
geographical, and scientific reasons. Historically, there are four
named oceans: the Atlantic, Pacific, Indian, and Arctic. However,
most countries - including the United States - now recognize the
Southern (Antarctic) as the fifth ocean. The Pacific, Atlantic, and
Indian are known as the three major oceans.
3. The Atlantic Ocean
4. The Atlantic Ocean covers an area of approximately
41,105,000 square miles. As the second largest ocean basin, the
Atlantic Ocean borders the east coast of the U.S., while the
Pacific, Earth's largest ocean basin, borders the U.S. West
Coast.
5. The Pacific Ocean
6. The Pacific Ocean is by far the largest of the world's ocean
basins, covering approximately 59 million square miles and
containing more than half of the free water on Earth.
7. The Arctic Ocean
8. The Arctic Ocean is the smallest of the world's five ocean
basins. With an area of about 5.4 million square miles, the Arctic
Ocean is about 1.5 times as big as the United States. It is
bordered by Greenland, Canada, Norway, Alaska, and Russia. The
average depth of the Arctic Ocean is 12,000 feet and it is 17,850
feet at its deepest point. The Arctic Ocean is almost completely
covered with ice for the majority of the year and its average
temperature seldom rises above freezing. However, this ocean is
anything but barren.
9. A warming climate can cause seawater to expand and ice over
land to melt, both of which can cause a rise in sea level.
10. Sea level can rise by two different mechanisms with respect
to climate change. First, as the oceans warm due to an increasing
global temperature, seawater expandstaking up more space in the
ocean basin and causing a rise in water level. The second mechanism
is the melting of ice over land, which then adds water to the
ocean.
11. Why is the Ocean Blue? Big Sur coastline looking north to
Bixby Canyon Bridge in California.
12. The ocean is blue because water absorbs colors in the red
part of the light spectrum. Like a filter, this leaves behind
colors in the blue part of the light spectrum for us to see. The
ocean may also take on green, red, or other hues as light bounces
off of floating sediments and particles in the water. Most of the
ocean, however, is completely dark. Hardly any light penetrates
deeper than 656 feet, and no light penetrates deeper than 3,280
feet.
13. Runoff and Pollution Although the ocean covers two-thirds
of the surface of the Earth, it is surprisingly vulnerable to human
influences such as overfishing, pollution from run-off, and dumping
of waste from human activity. This kind of pollution can have
serious economic and health impacts by killing marine life and
damaging habitats and ecosystems. Toxins from pesticides,
fertilizers, and other chemicals used on farms contaminate nearby
rivers that flow into the ocean, which can cause extensive loss of
marine life in bays and estuaries leading to the creation of dead
zones. The dumping of industrial, nuclear and other waste into
oceans was legal until the early 1970's when it became regulated;
however, dumping still occurs illegally everywhere.
14. Contaminants in the Environment
15. Oil and other chemicals can get into sediments, impacting
large coastal areas, threatening human health, and reducing the
economic well-being of regions that depend on a healthy coastal
environment. Our ocean and coastal areas provide us with a lot from
food, places to boat and swim, and wildlife to enjoythe list goes
on. So when these areas become polluted and unhealthy, it isnt just
bad for the environment, its also bad for us. At NOS, scientists,
economists, and other experts are busy monitoring, assessing, and
working to clean up contaminants in the environment.
16. The source A wide range of chemicals can contaminate our
water, land, or air, impacting the environment and our health. Most
contaminants enter the environment from industrial and commercial
facilities; oil and chemical spills; non-point sources such as
roads, parking lots, and storm drains; and wastewater treatment
plants and sewage systems. Many hazardous waste sites and
industrial facilities have been contaminated for decades and
continue to affect the environment.
17. The Impact Contaminants in the environment can look and
smell pretty nasty, but their impacts go beyond just aesthetics.
Some pollutants resist breakdown and accumulate in the food chain.
These pollutants can be consumed or absorbed by fish and wildlife,
which in turn may be eaten by us. Chemicals can also get into
sediments, impacting large coastal areas, threatening human health,
and reducing the economic well-being of regions that depend on a
healthy coastal environment.
18. Most ocean pollution begins on land
19. Eighty percent of pollution to the marine environment comes
from the land. One of the biggest sources is called nonpoint source
pollution, which occurs as a result of runoff. Nonpoint source
pollution includes many small sources, like septic tanks, cars,
trucks, and boats, plus larger sources, such as farms, ranches, and
forest areas. Millions of motor vehicle engines drop small amounts
of oil each day onto roads and parking lots. Much of this, too,
makes its way to the sea. Some water pollution actually starts as
air pollution, which settles into waterways and oceans. Dirt can be
a pollutant. Top soil or silt from fields or construction sites can
run off into waterways, harming fish and wildlife habitats.
20. Aquatic Vegetation - Eel grass
21. Eel grass, a type of submerged aquatic vegetation, supports
the life cycle of many fish and shellfish. The health of submerged
aquatic vegetation is an important environmental indicator of
overall ocean and estuary health. Seagrasses in bays and lagoons,
for instance, are vital to the success of small invertebrates and
fish. These small creatures are a food source for commercial and
recreational fish. Seagrasses also stabilize sediments, generate
organic material needed by small invertebrates, and add oxygen to
the surrounding water. Underwater vegetation in shallow coastal
waters also supports a wide diversity of marine creatures by
providing spawning, nursery, refuge, and foraging grounds for many
species.
22. Millions of species live in and around coral reefs
23. There Importance to the Ecosystem Hidden beneath the ocean
waters, coral reefs team with life. Fish, corals, lobsters, clams,
seahorses, sponges, and sea turtles are only a few of the thousands
of creatures that rely on reefs for their survival. Reef-building
corals are restricted in their geographic distribution by factors
such as the temperature and the salinity (salt content) of the
water. The water must also be clear to permit high light
penetration. Thousands of creatures rely on coral reefs for their
survival. Hidden beneath the ocean waters, reefs are also some of
the oldest ecosystems on the planet, reflecting thousands of years
of history.
24. Coral reefs are also living museums and reflect thousands
of years of history. Today, these important habitats are threatened
by a range of human activities. Many of the worlds reefs have
already been destroyed or severely damaged by water pollution,
overfishing and destructive fishing practices, disease, global
climate change, and ship groundings. However, we can still protect
and preserve our remaining reefs by acting now.
25. Are you aware Healthy coral reefs are valuable to you.
Coral ecosystems are a source of food for millions; protect
coastlines from storms and erosion; provide habitat, spawning and
nursery grounds for economically important fish species; provide
jobs and income to local economies from fishing, recreation, and
tourism; are a source of new medicines, and are hotspots of marine
biodiversity. These values contribute approximately $29.8 billion
to world economies each year. Continued decline of reefs will have
alarming consequences for people worldwide. The top threats to
coral reefs change, unsustainable fishing and land-based
pollutionare all due to human activities.
26. Coral, a sessile animal, relies on its relationship with
plant-like algae to build the largest structures of biological
origin on Earth.
27. Corals are sessile, which means that they permanently
attach themselves to the ocean floor, essentially "taking root"
like most plants do. We certainly cannot recognize them by their
faces or other distinct body parts, as we can most other animals.
The corals benefit, in turn, as the algae produce oxygen, remove
wastes, and supply the organic products of photosynthesis that
corals need to grow, thrive, and build up the reef. More than
merely a clever collaboration that has endured between some of the
tiniest ocean animals and plants for some 25 million years, this
mutual exchange is the reason why coral reefs are the largest
structures of biological origin on Earth, and rival old-growth
forests in the longevity of their ecological communities.
28. Ocean Habitat
29. The deep sea is the largest museum on Earth: There are more
artifacts and remnants of history in the ocean than in all of the
worlds museums, combined.