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The Winter 2010 issue of The Earth Scientist includes a variety of educational resources, ranging from astronomy to glaciers. Check out the other publications and classroom materials in our online store.

Quickie Questions - Earth - Oceans/Water

Date Answered Questioner (age, location) Question Answer
April 26, 2010Madison (Nebraska)What causes differences in the salinity of ocean water in different areas?There are two important factors to consider: (1) Evaporation increases concentration, so in areas where it is hot evaporation can increase salinity of the surface seawater. (2) Adding water to a solution decreases concentration, so, in areas where it rains frequently and in significant amounts, the salinity of surface seawater decreases.
April 23, 2010Pearl (Canada)Can you please explain to me the effects of the Atlantic Thermohaline Circulation and what would happen if it got thrown off or stalled as the level of salinity changedOur web pages Thermohaline Circulation: The Global Ocean Conveyor and Thermohaline Ocean Circulation describe and discuss in detail this topic.
January 15, 2010Graham (GA)What causes surface currents?The basic cause of surface ocean currents is the greater heating of the ocean and atmosphere at the equator than at the poles. The combination of the movement due to the raising of warm air (and water) and the one due to the spin of the earth causes air to move around, and the resultant movement takes warm air to toward the poles and back again in a close path. The wind blowing over the water surface is the main factor driving the ocean currents.
December 22, 2009Douglas (united states/CA)why do oceans have tidesTides are mainly related with the gravitational pull of the Moon. Our webpage Tides of the Ocean offers plenty of infrmation on this phenomenon.
December 17, 2009AVNEET (India)DUE TO LITTER IN WATER BODIES ARE THERE ANY GASES OR CHEMICALS THAT ARE DISSOLVED IN WATER?IF YES, WHAT ,HOW AND HOW MUCH ?DOES IT HAVE ANY BAD EFFECT ON MARINE LIFE,VEGETATION OR HUMANS? THANKS!!Many many chemicals are dissolved in the water. A recent report by the Ralph Nader Study Group, after reviewing over 10,000 documents acquired through the Freedom Of Information Act, stated that "U.S. drinking water contains more than 2100 toxic chemicals that can cause cancer." The causes of water contamination are numerous and range from agricultural runoff to improper use of household chemicals. Find more information on the website Water Contamination and its Effect on Our Health.
December 17, 2009calvin (FL)What is the main mineral type that the Oceanic plates are made of?The oceanic plates are made of dense, basaltic rock, predominantly composed of silica and magnesium.
June 2, 2009curios (kk) (ny)I wanted to know the oceans in order from greatest to least according to salinity.This NOAA map shows the mean sea-surface salinity. It can be helpful for answering your question.
May 18, 2009Amanda (America)What is 5 examples of groundwater?The general definition of groundwater is water located beneath the ground surface. The most typical aception is liquid water flowing through shallow aquifers, but it could also include other water reserves such a soil moisture, permafrost, immobile water in very low permeability bedrock, etc.
April 14, 2009Zac (CT)What are Ocean Biomes?The ocean holds the largest of Earth’s biomes. It covers 70% of the planet’s surface. Life in the ocean is diverse. The smallest creatures that call the ocean home are so tiny that they can only be seen with a microscope. The largest creatures are blue whales, which can be as much as 34 meters (110 feet) long. There are many different ways to live in the ocean, too. Some animals travel huge distances through ocean water. Others stay in the same place on the ocean floor their entire lives. Some burrow beneath the sand while others float near the surface. More information on our webpage The Ocean Biome.
March 25, 2009Robert (Australia, Queensland)How does convection in the earths ocean effect global warming?Convection currents on the ocean move heat to different depths. If the amount of heat available on the surface changes, these currents, and the life that depends on them, will also suffer changes.
March 4, 2009dabielle (arkansas)which current flow off the southcoast of the united states?The south coast of USE lies mainly around the north part of the Gulf of Mexico, where the Gulf Stream flows.
February 19, 2009 how mutch water is on and in earthIt has been calculated that there are something like 326,000,000,000,000,000,000 gallons (326 million trillion gallons) of water (roughly 1,260,000,000,000,000,000,000 liters). More information here.
October 21, 2008madvee (quatre bornes)how can we use temperature to calculate the depth of sea water??what if i send a diver underwater,he monitors a temperature at a time t..and soon after he records a new temperature less than t,the sea level must have increased but by how much?and what is the new depth?How to use the temperature/depth graph to predict the result?I hope that you will reply to my questions very soon.I thank you in anticipation.Temperature and depth are not linearly correlated. Most of the solar radiation (light and heat) that hits the ocean is absorbed in the first few tens of meters of water. Waves and turbulence mix this heat downward quickly. The surface layer of the ocean is well mixed from the top to the bottom of that layer. Deeper layers are not mixed, and there the temperature changes more uniformly. Please, visit our webpage Temperature of the Ocean Water for a detailed discussion on this topic.
July 8, 2008Sibusiso (South Africa)What are the 10 characteristics of warm ocean currentsThis page from the Office of Naval Research offers a good amount of information about ocean currents.
June 18, 2008selena (bronx)what types of currents move ocean water?Ocean water moves a lot! Tides, waves, surface currents, and deep water circulation are all types of ocean water movement. Our web page Currents of the Ocean offers more information on this topic.
April 22, 2008Lola (West Virginia)What evidence did scientists find that supports the theory of sea-floor speading??The theory of sea-floor spreading is widely supported by the evidence. Samples obtained from the ocean floor showed that the rocks and sediments are gradually younger when the mid-ocean ridge is approached.
April 1, 2008nicole (North Carolina)what percentage of the earth is covered by salt water?About 70% of the Earth is covered with water. Over 97% of that water is found in the oceans.
March 27, 2008geralyn (philippines)what are the different parts of the ocean?There are many clasifications. Some of the physical features of the oceans are: continental shelf, continental slope, continental rise, submarine canyon, submarine fan, mid-ocean ridge, ocean trench, guyot, seamounts, abyssal plain, oceanic islands. From a biological point of view, there are the Euphotic zone, the Dystophic zone, and the Aphotic zone.
October 16, 2007michael (tn/usa)what is a hydrosphere, and how does it fit with the earths layers (like the crust,or mantle)?The hydrosphere includes all water on Earth, and is not a "layer" in the classic sense, although it intearcts with all systems and layers of the planet.
September 11, 2007Emma (New Zealand)If global warming affects the thermohaline circulation (other than slowing or stopping the Nth Atlantic Drift Conveyor, causing cooling ) what are the potential affects in the Sth Pacfic and Sth Atlantic?A thermohaline circulation shutdown could have other major consequences apart from cooling of Europe, such as an increase in major floods and storms, a collapse of plankton stocks, warming or rainfall changes in the tropics or Alaska and Antarctica (including those from intensified El Niño effect), more frequent and intense El Niño events, or an oceanic anoxic event (oxygen (O2) below surface levels of the stagnant oceans becomes completely depleted - a probable cause of past mass extinction events). Extracted from Shutdown of thermohaline circulation.
July 23, 2007Mimi (philippines)why salinity is called the limiting factor that affects the distribution and growth of aquatic animals and plants?Most creatures that live in the ocean could not live in fresh water. However, when the highly saline waters of the ocean meet fresh water, an estuary is formed. This is a special environment where some creatures have learned to adapt to a mixture of fresh and salt water. When fresh water, ground water and soils are altered by human actions and salinity greatly increases, it can have an extreme detrimental effect on life there. Changes in salinity brought about by human residential, commercial and industrial activity can kill plant life, aquatic life, and animal life in a given area. Our web page Salinity discusses in detail this topic.
December 6, 2006Zachary (Florda)how do tsunami formA tsunami can be generated by any disturbance that displaces a large mass of water. Tsunamis have several causes, but the most common one are submarine earthquakes. Submarine landslides, submarine volcanic eruptions and (very rarely) large meteorite impacts in the ocean can also cause tsunamis.
July 2, 2002Paul (Australia)What would happed if the earths polar caps would melt?? Would we be submerged? And how much by if so....??There are many different theories of how fast sea levels will rise in the future and most are based on how fast the ice covering Antarctica is melting. At the South Pole, the land surface of Antarctica is covered with a massive Ice Sheet. If the entire Ice Sheet melted, scientists estimate that sea level would rise about 70 meters (230 feet), however, the scientists believe that it is very unlikely that the entire ice sheet melts any time soon! Other scientists believe that if a large piece of Antarctic ice, called the Ross Ice Shelf, melts, the Ice Sheet that covers Antarctica may begin to collapse. In this case, the melting ice would cause sea level to rise as much as 6 meters (20 feet) in the next 250 to 400 years.

Unlike the South Pole, most of the ice near the North Pole is not on land, except for the ice sheet that covers Greenland. It floats in the ocean as icebergs. If those icebergs melt, sea level will not rise because the ice is already in the water. (Try this at home by letting ice cubes melt in a glass of water!).

August 20, 2001Sandra (New Jersey, USA)What is the difference ('technically speaking') between a creek and a river?According to Webster's Dictionary, a creek is just a stream of water that is smaller than, and often a tributary of, a river.
July 25, 2001Tommy (Singapore)What method can I use to find out how much salt there is in sea water?There are a few ways of doing this. The simplest way of directly seeing the salt in sea water is to let it the water evaporate. You could do this by putting sea water in an open container in the sun. As the water dries, the salt will be left behind, and you should eventually be able to see a crust of salt where the water was. (note: this is not a very accurate way to measure the salinity of water because some of the chlorides will be lost in the last stages of drying...but it will give an approximate!)

There are other ways that don't take as long and are more accurate, but they involve complicated equipment such as a CTD instrument (measuring the ability of water to conduct electricity, for instance, because the more salt in water, the better electric current flows).

March 19, 2001Amanda Are there any goddesses of the sea?Amphitrite was one of the sea-nymphs called the Nereids. Galatea was also a sea nymph. Sedna was a sea spirit of the Inuit people.
October 4, 1999Brandon (Iowa, USA)What is the depth of the deepest ocean?The Mariana Trench, in the Pacific Ocean, is the deepest point in the world, at a depth of 11,033 m.
August 11, 1999Sivan (Israel) Why do the waves crash to the shore all over the world? What makes them go to the shore?The answer to this question is very simple. The wind forces the water towards the shore. Why the wind does this is a little more complicated!

Sea breeze is a term used to describe this special type of wind. During the day, the shore heats up much faster than the water. Hotter air rises, so the air above the shore rises up, creating a low pressure area. Air in a high pressure will flow towards the low pressure, so the air above the water blows into the low pressure to fill it. Along the way, it forces the water near the shore in the same direction!

Waves will get larger if there is more wind, such as when a storm is coming towards shore.

July 28, 1999Charlie (Texas)What is the deepest water and can we get there.The deepest water in the world is the Marianas trench in the Pacific Ocean, about 200 miles SW of Guam. The trench is 36,198 ft or 11,033 m deep. The bottom was reached in 1960 by two men in a U.S. navy bathyscape.
May 28, 1999Levar (Maryland, USA)I am doing a science project on can air and water occupy the same space. my dad showed me how a glass turned upside down in a sink of water the glass did not fill up with the water. i tried to look it up in the library but i don't think i am looking for the right section. can you answer my question?It is possible for gases (air) to diffuse into water. Fish actually breathe oxygen dissolved in water. The air can dissolve through turbulence (mixing) or if the contents are under pressure. A good example of gas dissolved in a liquid is a bottle of pop. When you open it up the CO2 gas dissolved in it starts to fizz out, yumm.
May 19, 1998Raza (Pakistan) What are the different effects of the Moon on the Earth?The largest impact of the Moon on the Earth is through tidal forces. The Moon's gravitational pull does indeed pull on the bodies of water on the Earth, creating high and low tides. Land doesn't move as easil y as water, but in some places the Earth's surface does rise and fall 1-2 inches because of the Moon's gravitational pull.

Finally, I've heard many people blame hyperactivity or just anomolous behavior in general on a full Moon. I don't know that the re is much scientific evidence for a full Moon affecting emotions or behavior, but I do know that during a full Moon, some strange things go on...for instance, it has been documented that during a full Moon, more baby animals are born than any other time during a month. You decide!

March 11, 1998Ingrid (Florida, USA) Why are oceans salty?Most of the salt in the sea comes from minerals that were part of the solid Earth (land!). When rivers flow over rocks on land, minerals get dissolved by the river water. These minerals are deposited into the oceans as the rivers flow into the oceans. The most abundant mineral in seawater is of course sodium chloride, or common salt. If all the salt in the ocean were dried, it would form a mass of solid salt the size of Africa!
February 17, 1998Salma (Egypt) When and why does 'high tide' happen? and when and why does neap' lower tide' happen?The highest tides (spring tides) occur when both the Sun and the Moon are pulling in the same direction on the Earth. The lowest tides (neap tides) occur when the Sun and Moon are pulling the Earth in opposite directions.

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