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Oceans: Top 10 Questions

May 2016

Thanks to Thanks to David Wilkins, associate professor of geosciences, Boise State University; and Walter Snyder, professor emeritus from the department of geosciences, Boise State University for their answers. for the answers.

1: Why do ocean waves keep going and how?

Far off shore, ocean waves are really just energy passing through water. The energy is generated and transferred to the water by lots of wind from storms or just general breezes blowing over a long period of time. As the winds blow harder and harder, they also transfer more energy to the water. This generates large waves that move in front of the wind when the wind dies. The energy keeps on moving through the water until it hits something that stops it. It doesn't slow down or dissipate until it comes to shore. Then you start seeing that energy transferred again as the waves begin to pile up and surf forms. You have the waves crashing against the rocks and waves crashing against the shoreline. That's where the rash of waves will end. (From Sydney at Sagle Elementary School in Sagle)

2: Why does the ocean have salt in it?

The ocean has salt in it because of rivers. When rain falls on land, it is slightly acidic and starts dissolving the minerals in rocks. From those minerals, like sodium, calcium and potassium, other elements are leached out of the rocks and into the water. This runs down the hills into streams, streams into rivers, and eventually into the oceans. The small amount of salt that goes with it, isn't much in the rivers, but it accumulates in the ocean over billions of years. (From Josh at Sagle Elementary School in Sagle)

3: Why is the ocean blue, green or gray in parts?

Ocean water is essentially clear. With depth and with sediments like plant matter, and other things floating in the water, different colors are added to what we see. Near the shore, you see tans, grays, gray greens, and light greens as the sunlight bounces off the bottom. As you get deeper and deeper, the sunlight doesn't have anything to bounce off of. By the time you get to about 300 feet deep, the only light left at this stage is blue light. With regards to light, there is blue on one end of the spectrum and red on the other. The red gets absorbed first in the shallows, and then we are left with blue in the deeper waters. Gray is somewhere in the middle. So, depth and the amount of sediment in water impact the colors we see. (From August at Riverside Elementary School in Boise)

4: What is the deepest point in the ocean?

The deepest point in the ocean is the Mariana Trench. It occurs in the eastern Pacific ocean right in front of the Mariana Islands, an island chain that extends southward from Japan. That trench is almost seven miles deep. Mount Everest would disappear in that trench. (From Jackson at Riverside Elementary School in Boise)

5: Is coral being destroyed by humans?

Yes. Coral is being destroyed or at least stressed by some of the activities that we do. The chemicals from sewage and other things that we put into the ocean are harmful. Corals are very, very sensitive animals and some chemicals are toxic to them, causing them to die. A recent study looked at the effects of sunscreen that we wear in the water. This chemical is highly toxic to coral. Climate change has also affected this animal. Man has contributed to global warming, and these warmer water temperatures have had a negative impact on coral. (From Brock at Adams Elementary School in Boise)

6: How do plants grow on the ocean floor with no sunlight?

Plants on the surface of the earth need sunlight to provide and create food through photosynthesis. Since water absorbs more and more light as you go deeper and deeper in the ocean, the sunlight gets less and less at greater depths. Plants have evolved to use less and less light. Sunlight will actually go down about 300 feet in the water before it is no longer visible. So beyond that point, plants aren't able to photosynthesize. There is no sunlight for them to work with. At very great depths, there are some plants and organisms, largely bacteria, which have evolved to generate food from chemicals in the water. They use the process called chemosynthesis. Chemosynthesis uses chemicals to generate food. (From Cooper at Adams Elementary School in Boise)

7: How do whales sleep if they have to breath air?

When whales sleep, they are only half sleeping. Perhaps they are half awake and half asleep to protect themselves from predators and to make sure they don't drown. When they are asleep they kind of float on the surface of the water. They can hold their breath for long periods of time because their blood type can hold oxygen for long periods of time. They breathe very, very slowly; and when they go under water, they can actually hold their breath for 30 to 45 minutes at a time. (From Lewis at Adams Elementary School in Boise)

8: How do dolphins communicate?

Dolphins communicate with each other through different means. They use body language to communicate their emotions. How they present themsleves can let other dolphins know if they are upset or excited. They also use clicks and whistles. They use a certain whistle sound to identify themselves to other dolphins. They use click echoing to find things and find fish. They can actually use the clicks to stun their prey so they can eat it. (From Ben at Adams Elementary School in Boise)

9: How does the moon affect the ocean?

The moon affects the ocean by creating tides. The moon is big enough that it has a gravitational pull on the earth. That gravitational pull will actually pull the water toward the moon. That puts a bulge around the earth toward where the moon is. When you have a bulge, it pulls water away elsewhere. So, it lowers the water away from it, making it bigger right next to it. When the earth spins through that bulge, you have a high tide. When you go through the bulge, it's high tide. When you come out of the bulge and are at the side of it, you get low tide. The moon helps create the tides that we see. (From Nick at Riverside Elementary School in Boise)

10: Which ocean is the biggest of them all?

The biggest ocean is the Pacific at about 64 million square miles. The Atlantic is about half that size at 33 million square miles. (From Sadie at Kamiah Elementary School in Kamiah)


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