Let’s play a little quiz game thanks to some of the Sierra Club Knowledge Cards, see how much you know about water and the oceans. I encourage you to to buy as presents these fun decks of cards, a good companion for road trips, both interesting and educational. They can be bought HERE.
(Answers at the bottom of the post)
1 What percentage of the Earth’s surface is covered by water?
a. 40%
b. 50%
c. 60%
d. 70%
2 The ocean holds about 97 % of the waters on Earth. Where is the rest?
a. 80% is freshwater and 20% is ice
b. 60% is freshwater and 40% is ice
c. 40% is freshwater and 60% is ice
d. 20% is freshwater and 80% is ice
3 What percentage salts are in seawater?
a. 0.034 %
b. 0.34 %
c. 3.4 %
d. 34%
Swimming in the Dead Sea
4 Which ocean receives the outflow from most of Earth’s great rivers?
a. Pacific
b. Atlantic
c. Indian
d. Antarctic
5 The fastest and most powerful of the world’s ocean currents is the…
a. Agulhas Current
b. Benguela Current
c. Gulf Stream
d. South Equatorial Current
6 How many marine mammals are killed or injured each year by US commercial fishing operations?
a. 100
b. 1,000
c. 10,000
d. 100,000
7 What is the average depth of the Earth’s oceans?
a. 1 mile
b. 2 miles
c. 3 miles
d. 4 miles
8 How long does the average iceberg stay around before breaking up and melting?
a. 4 months
b. 2 years
c. 4 years
d. 20 years
C19A iceberg in Antarctica, the largest existing iceberg
9 The most radical variation between high and low tide is found at the Bay of Fundy, in northern Canada. By what difference?
a. 10 feet
b. 50 feet
c. 100 feet
d. 500 feet
Alma, New Brunskwick, at high and low tide
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ANSWERS:
1 d. Water covers 70% of the earth. Only 3% of that water is fresh and rivers hold only about a millionth of the earth’s total water. Freshwater lakes hold about 100 times more water than the rivers and there are also 3,100 cubic miles up in the atmosphere and 2,000,000 cubic miles of groundwater.
2 d. That minuscule 3% of freshwater is mostly stored in the ice caps. 80% of all freshwater is there. Antarctica holds as much drinking water in solid form as the Atlantic does in liquid, with an average ice thickness of 7,000 feet.
3 c. Seawater is about 96.5% water and 3.4% salts. Salinity tends to decrease with depth and with proximity to the equator. If you let a cubic foot of seawater evaporate you would be left with roughly 2.2 pounds of salt. But because of their volume the oceans still manage to contain as much as 50 quadrillion tons of salt. Where we to extract all that salt and sprinkle it uniformly over the planet’s land surface we would form a nice 40 story high crust.
Marakkanam Salts, in India
4 b. Most of the continental landmasses that surround the Atlantic are sloped “downhill” in its direction. Rivers such as Elbe, Loire and Rhine in Europe, the Niger and the Congo in Africa, the Mississippi and St. Lawrence in North America and the Amazon, Orinoco, Paraná and Uruguay in South America.
5 c. The Gulf Stream can flow North at a speed of 5 mph, moving 55 million cubic meters of water per second (300 times the flow of the Amazon River). It is about 45 miles wide and up to 1,500 feet deep, traveling 100 miles in a day.
Ocean currents are caused by the push of prevailing winds and are subject to the same Coriolis force that guides winds: to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
The first person to chart the Gulf Stream was no other than Benjamin Franklin, back in 1770.
6 d. According to government calculations as many as 100,000 marine mammals are killed or injured each year by the US commercial fishing fleet. There are collisions with boats, entanglement in fishing lines and accidental hauling as “bycatch” in fishnets. One of the biggest problems occurs with spotted and spinner dolphins, which like to swim with schools of yellowfin tuna and are often harassed or killed by the tuna fleet. But even when fishing operations do not directly kill or injure marine mammals, they can indirectly harm species by depleting fish stocks these animals rely upon. Such is the case in Alaska, where overfishing of pollack and other groundfish has caused a 90% decline in the Steller sea lion population in the region.
7 b. Two miles. Overall, the Atlantic basin has the shallowest waters and the Pacific the deepest. If you dropped Mount Everest into the Mariana Trench its top would still be covered by more than a mile of water. The Mariana Trench’s maximum-known depth is 6.831 miles at the Challenger Deep.
8 c. Icebergs have an average lifespan of about 4 years. For most of that time they remain fairly close to the area where they are calved. Once they drift into the shipping lanes (with warmer waters) they last about a year.
The largest existing iceberg up until now is C19A, renamed Melting Bob in 2008. It is an iceberg off Antarctica with an area of 2,200 square miles.
Scientists say the large icebergs calving from Antarctica in recent years are not related to global warming, but are entirely natural. The ice cap is 2 miles thick and moves each year about 1/2 mile towards the sea before it breaks off.
9 b. 50 feet. Oceanographers believe this is due to the bay’s shape, with a broad mouth that lets a lot of ocean water into a relatively small container. Very different from the Mediterranean and the Gulf of Mexico, where small areas of interface with the open ocean mean very small tidal variations.
