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Oceans And Seas

Overview

The oceans and seas cover 71 percent of the earth’s surface and are the habitat for thousands of species of marine life including phytoplanktons and planktons, corals, fish, dolphins and whales comprising a food chain essential to the health of the ecosystem.

The ocean habitats and ecosystem are principally under threat from:

1. Warming of the oceans, which can reduce phytoplankton, krill, and other marine life at the bottom of the food chain.

2. Absorption of CO2 from the atmosphere, which decreases seawater alkalinity causing potential detrimental effects on skeletal sea life including coral reefs.

3. Pollution from fertilizer run-off, untreated sewage, toxic chemicals, and garbage (especially plastics), which contribute to dead zones.

4. Overfishing, which reduces fish populations such as cod in the Grand Banks off the coast of Newfoundland.

Supporting Viewpoints

The amount of overall temperature rise in oceans is contentious, but in some localized areas is more evident than others. According to the IPCC 4th Assessment report as summarized by the UCCS, “since 1961, the world’s oceans have been absorbing more than 80 percent of the heat added to the climate”. Marine life at the bottom of the food chain, such as phytoplankton, are most susceptible to warmer waters.

In addition to warming, the oceans have absorbed about half of the atmospheric CO2 in the past 200 years, resulting in the surface ocean pH dropping from approximately 8.25 to 8.14. The potential detrimental effect of continued ocean acidification on the biodiversity of the food chain could reduce the food fish population to extremely low levels.

Fertilizer run-off from farms and lawns stimulate algal blooms that result in oxygen depleted dead zones in places like the Gulf of Mexico, offshore California and the Baltic Sea. Land based solid garbage, especially plastics, often reaches the oceans. A sea of plastic by one estimate “twice the size of Texas” is floating in the Pacific Ocean 800 miles north of Hawaii. Toxic chemicals, including pesticides and heavy metals such as lead and mercury, affect marine life and enter the food chain for ultimate human consumption. Untreated or under-treated sewage disposal in parts of the world such as the Mediterranean Sea flows into the ocean or major seas.

Over-fishing has become more acute with the use of giant high tech factory ships that use sonar devices and planes to locate schools of fish, giant nets to encircle and trap the schools, and giant hoses to “vacuum them up”. The practice removes essential fish from the food chain and is devastating to the fish population in some areas. A 2003 global study by Myers and Worm concluded that 90 percent of the world's large fishes have disappeared over the last half-century by industrial overfishing; these practices can have a serious effect on the ecosystem of the oceans. The Marine Stewardship Council “promotes environmentally responsible stewardship of the world's most important renewable food source”.

Supporting Websites
Mongabay.com
Union of Concerned Scientists (IPCC Summary)
World Wildlife Fund WWF
RealClimate
Greenpeace
Marine Stewardship Council

Opposing Viewpoints

The anti-global warming advocates take issue with the linkage of human generated green house gases as the cause of global warming and ocean warming. Global warming and cooling periods have been a part of earth’s natural cycles for thousands of years.

Another view is that the build-up of CO2 in the atmosphere and the absorption of CO2 by the oceans will mitigate over time as fossil fuels are slowly used up and alternative clean energy supplies become more dominant.

The fisheries industry is generally supportive of monitoring control and surveillance as a means of protecting fish populations from illegal fishing and overfishing, but locally some disagreements have arisen.

Opposing Websites
GlobalWarmingSkeptics


Oceans And Seas Content

Video:
Oceans becoming a garbage patch
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Published:11/9/2007
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Submitted by:Frank K 210 days ago
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Categories: Habitats & Oceans And Seas
Oceans And Seas
Article:
Our oceans are turning into plastic...are we? - Susan Casey, Best Life Magazine
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Published:10/25/2007
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Submitted by:Frank K 219 days ago
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Categories: Oceans And Seas & Waste Management
Article Details:   A vast swath of the Pacific, twice the size of Texas, is full of a plastic stew that is entering the food chain. Scientists say these toxins are causing obesity, infertility...and worse. It is dubbed the "Eastern Garbage Patch" by scientists.
Habitats
Article:
Rapid worldwide depletion of predatory fish communities - Ransom Myers and Boris Worm
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Published:5/15/2003
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Submitted by:Frank K 211 days ago
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Categories: Habitats & Oceans And Seas
Article Details:   The authors'analysis suggests that the global ocean has lost more than 90% of large predatory fishes. This is the first analysis to show general, pronounced declines of entire communities across widely varying ecosystems. The potential ecosystem effects of removing 90% of large predators from the open oceans is bound to be widespread, and possibly difficult to reverse.



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