What's Your Oceans IQ?

Well, 70.78% to be exact, but 71% is close enough. In either case, 98% of the water on the planet is contained in the world's oceans, which means - you can probably see where this is going - the vast majority of water on the planet is too salty for human consumption. Read more about how people are trying to desalinate sea water to make it potable.

Water Conservation: Getting Techie

Humans have been seriously altering the ecosystems of the world's oceans for at least the past 1000 years, but since the advent of industrial fishing techniques the problem has reached global proportions. Rapidly growing human populations haven't helped things one bit, either. Today the demand for fish is so high at least 80% of the world's fisheries at risk of being overfished and collapsing.

Read more, from Planet Green NGO partner Oceana:
Over 80 percent of fisheries overfished: report

Find out what fish aren't being overfished:
Monterey Bay Aquarium's Endangered Seafood Guide

Encompassing the area around the North Pole, the Arctic Ocean is not only the smallest of the world's major oceanic divisions, but it's also the shallowest. Its average depth is a bit over 1,000 meters, about one-quarter that of the Pacific Ocean.

Read more about how climate change is leading to melting sea ice:
Arctic Sea Ice Not Only Covers Less Area, Its Thinner Too: New Data Shows
Focus on Focus Earth: Opening of the Arctic

Though A is partially correct, water does pick up some reflection from the sky, in fact water is blue unto itself - even though in quantities we're used to dealing with it appears clear. This blue color deepens as the depth of water increases. The reason for this? Water molecules nuclei absorb red photons from the incoming light. The reason different bodies of water are different colors has far more to do with impurities and dissolved material in the water than the color of the sky.

Though images of ships run aground on sand, miles from the nearest remaining parts of the Aral Sea make for shocking images, global climate change had nothing to do with the drying up of the Aral Sea. In fact, though it was once the world's fourth largest inland body of salt water, after the Soviet Union diverted the Amu Darya and Syr Darya rivers which flowed into the Aral, for irrigation of nearby crop lands, the sea began shrinking. By 2007 it was less than 10% of its historic size. Recent efforts to dam the northern part of the sea to retain and refill some of the water have been somewhat successful, but at the expense of further drying of the southern half.

Read more:
NASA Documents the Evaporation of the Aral Sea (2000-2009)

Of the world's major oceanic divisions, the Atlantic Ocean is the saltiest. In the open ocean the salinity of the Atlantic is between 33-37 parts per thousand (3.3-3.7%) - that's actually not that much different at the high end than other oceans, but the others can go as low as 32 ppt. The areas with lowest salinity are found just north of the equator, where heavy tropical rainfall changes it, and along coasts where major rivers empty into the ocean. The saltiest parts of the ocean are about 25° north and south of the equator where a combination of low rainfall and high evaporation increases salinity.

Read more:
Scientists Launching Satellite to Measure Salinity of the Seas

This one has developed into a bit of an urban climate myth. Though climate change could result in a slowdown of the Gulf Stream and ocean circulation, ultimately only moderate cooling would result. And in fact, any cooling that would result would likely be overwhelmed by rising greenhouse gases.

Read more from Columbia University's Lamont-Doherty Earth Observatory:
Climate mythology: The Gulf Stream, European climate and Abrupt Change

Yikes! That's about 1.4 million square kilometers. (Some estimates place the area as high as 15 million square kilometers, but twice the size of Texas is a conventionally held estimate). If you were just guessing on this question, and don't even know what the Great Pacific Garbage Patch is, this is the gist of it: Due to the way the Pacific circulates, much of the plastic waste that unfortunately ends up getting dumped in the ocean gets pushed into one area. All that trash weighs in at over 100 million tons. Remember, plastic doesn't biodegrade, it only gets broken down into smaller and smaller bits of plastic, and if you're in the Pacific it all ends up getting pushed into this massive floating garbage pile.

Read more:
First Great Pacific Garbage Patch Clean-Up Effort to Begin
Green Glossary: Great Pacific Garbage Patch

Ocean dead zones - areas of the world's oceans which have abnormally low levels of oxygen in them - are a growing problem, with about 405 now known to exist and more likely because of climate change. The main cause of them is runoff from chemical fertilizers causing an increase in nutrients in the water leading to blooms of algae. When the algae dies and decomposes it causes these low-oxygen conditions. However, runoff from sewage systems, urban land use, and animal runoff from farms also contribute to the problem.

Read more:
Crop Biodiversity a Cure for Ocean Dead Zones?

As amazing as that may seem to the non-mariners of the world, at a size of 179.7 million square kilometers, all of the Earth's landmass could easily fit within the boundaries of the Pacific Ocean. In fact another entire African continent could fit in to boot. Other outstanding facts about the Pacific: It contains more islands (about 25,000) than the rest of the world's oceans combined; it has the lowest point on Earth, the 10,911 meter deep Mariana's Trench; at its widest point of 19,800 kilometers it covers nearly half the planet.

Read more: Focus on Focus Earth: Ocean Protection