Oceanography Week 1 Study Questions

List four reasons to care about the oceans?

1. They are home to a massive about of the planet's biodiversity. 2. The currents and large bodies of water are responsible for weather patterns across the globe. 3. They help regulate Earth's temperature gradient by transporting warm and cold water around the globe. 4. 50% of human pop lives along coast

What percent of Planet Earth is covered with water?

71%

What advantages would a culture have if it could use the ocean for transport and resources?

Being able to use the ocean for transport allows people to take advantage of fast-moving currents and strong winds to travel quickly between places. It also avoids having to travel over rocky or rough terrain, again making the process faster. The resources one can get form the ocean are extensive and being able to take advantage of them gives cultures another source of food and produce to exploit for personal use and economic trade, giving them an edge over landlocked cultures and societies.

How can the height above the horizon of the North Star be used in navigation?

By calculating the angle between the North Star and the horizon, you can estimate what latitude you're at—so long as you're in the northern hemisphere.

What technological advancements allowed the Chinese to explore and trade in the 15th Century?

Chinese inventors invented the compass as well as the central rudder, watertight compartments, and sophisticated sails on multiple masts.

Why is there so much "life" around volcanic islands (seamounts)?

Deep sea ocean currents rich in nutrients collide with base of the seamount and follow it upwards towards the surface where it's able to provide food to a multitude of organisms.

Why was the invention of the "echo sounder" so important for understanding the oceans?

Echo sounders are important because they allow scientists to accurately measure to depth of an ocean by sending sound waves down into the ocean and measuring the time it takes for the pulses to reach the bottom of the ocean and then bounce back to the ship. These depth measurements are important because they allow us to "map" the floor.

How did Eratosthenes use water wells to figure out that the Earth was spherical and how did he determine its size?

Eratosthenes realized the Earth was curved because he heard from travelers from modern day Aswan that at noon on the longest day of the year, the sun shone directly over a water well. When he measured the angel of shadow being cast by a nearby pole, he realized that the sun must be casting parallel lines of light on the Earth (since it was so far away) and that the reason for the shadow in Alexandria not lining up with the water well in Aswan must be due to the curvature of Earth's surface. Using the information, he garnered from his water well experiment and the distance between Aswan and Alexandria, Eratosthenes was able to calculate the circumference of the Earth using geometry.

Why do Hammerhead Sharks come to seamounts?

Hammerheads go to seamounts to get cleaner fish to eat the fungus and bacteria off their skin.

Why was determining longitude so important and what was needed to do it?

Longitude is important because it tells where on the east-west plane you are located. Without it, you wouldn't be able to estimate how far from a certain place you are or how far you've traveled. Latitude and longitude are both needed to find your location on the globe. You find longitude by using a clock. First you determine local noon by observing the path of a shadow of a vertical shaft—noon is when the shadow is shortest—and set your clock accordingly. After traveling for a distance, the clock will no longer line up to when the shadow is shortest and by using some simple math you can figure out how far you have traveled from your starting point.

What is the basis of all life in the ocean?

Microscopic phytoplankton serves as the basis of all life in the ocean. It is the very beginning of the food chain, getting its own energy from the sun's rays and then being used as a source of food for larger animals.

What had to happen (what was needed) to allow "more ambitious" voyages?

More ambitious voyages required coordination with the astronomical direction, since sailors couldn't rely on just following the coastline, and this required knowing the size of the Earth. It also required better timekeeping to estimate longitude. This voyages also required advanced shipbuilding technology so the boats could withstand ocean currents and storms and accurate graphic charts.

How is Oceanography different from most of the other sciences?

Oceanography is an interdisciplinary field that combines aspects of astronomy, geology, geography, biology, chemistry, and physics.

What benefits did the oceans offer early humans?

Oceans provided a source of food for early humans. Along coastlines people could harvest bivalves, crabs, snails, fish, birds, and various plants. Deeper in there was even more food to be found and various cultures sprung up around ocean life from the Inuit people in the Artic to the Pacific Islanders. Oceans and seas also allowed for travel and trade between societies and the Phoenicians took full advantage of this fact, becoming one of the first and most successful traders in the Mediterranean.

What were the stimuli to Polynesian colonization? How were the long voyages accomplished?

Polynesian colonization of the Pacific islands was driven largely by trade and a search for resources. Later exploration and colonization were also spurred on by religious wars, with the losers being banished and needing to explore islands farther afield to find new places to live. These long voyages were accomplished by improving seafaring technology and practices. Voyagers sailed across the ocean in massive double-hulled seafaring canoes and became experts at navigating via the stars, the currents, and seafaring birds, and many other signs

Why have satellites been so important regarding understanding the oceans?

Satellites can get a birds-eye view of the oceans from space and help us track weather patterns and study the formations of massive storms like hurricanes and monsoons. They also give us a clearer picture of temperature gradients across the oceans. Newer satellites can determine the height of the water's surface as well the precise directions of ocean currents along with wind speed and direction.

Why do Sea turtles lay all their eggs on the same day?

Sea turtles lay their eggs all within the same couple of days to ensure that their babies have safety in numbers. The idea is that when the babies hatch there will be so many baby turtles that the predators preying on them won't be able to eat all the turtles and most of the babies will escape.

What is the difference between an ocean and a sea?

Seas are smaller and shallower than oceans. They are often very salty and are usually surrounded by land but connect in some way to oceans.

What was the first purely scientific oceanographic expedition and what were some of its accomplishments?

The Challenger expedition was the first organized expedition focused solely on scientific research. The scientist took temperature, salinity, and density measurements as well as measuring the depths of the ocean they traveled across. They were able to prove that life exists below 549 meters, which had been the reigning theory at the time. They measured depths up to 8,185 meters and discovered 4,717 new species.

What is mean by "reverse tribute" and who used this approach during exploration?

The Ming Dynasty of China used reverse tributes, or gifts, to show off the wealth, power, and kindness of their empire to distant lands during their maritime explorations.

What two ways did the Phoenicians use to navigate around the Mediterranean Sea?

The Phoenicians followed the coastline and used the North Star to navigate the Mediterranean.

What is special about the Sargasso Sea?

The Sargasso Sea exists in the Atlantic and is the only sea without a land boundary. It is special because it's defined entirely by the surrounding ocean currents. It is named after a genus of free-floating seaweed called Saragarum and the Sargasso Sea harbors a unique specimen that floats freely around the ocean and reproduces vegetatively on the high seas.

What were the reasons that the Vikings explored west to North America?

The Vikings began their seafaring explorations as raiders and for a long time mostly stuck to raiding coastal cities and towns across Europe and the Mediterranean. The discovery of Iceland and Greenland was caused when Viking ships were blown off course and found the islands. They continued exploring in search of new lands to settle and new resources to exploit. Their expansion to North America was the result of one man's sketchy account of the fertile land that made people willing to risk ocean travel to settle a new land and trade with new people.

Compare ocean depths to land heights.

The average ocean depth is 3729m (12,234ft) while the average land elevation is 870m (2756ft). Deepest part of the ocean is the Mariana Trench in the Pacific Ocean; it is 11,022m deep (36,161ft). By comparison the highest continental mountain is Mount Everest which stands at 8850m (29,935ft). the oceans are deeper than the land is high.

What is the largest animal to ever inhabit planet Earth and what does it eat?

The blue whale is the largest animal to live on Earth. It mostly eats krill.

Compare the five main oceans on the planet, which is largest/smallest, deepest/shallowest, ice-covered, and unconstrained by landmasses

The largest and deepest ocean is the Pacific Ocean. The Atlantic Ocean is the second largest ocean and almost as deep as the Pacific. It's also my native ocean so that's a point for the Atlantic. The Indian Ocean, which is largely in the southern hemisphere and is also almost as deep as the Pacific. The Artic Ocean is the smallest and shallowest of the five oceans and is mostly covered in ice. The Antarctic Ocean connects the Pacific, Atlantic, and Indian oceans and not constrained by landmasses, but by incredibly strong ocean currents.

What is the largest migration of life on the planet, explain?

The largest migration of life on the planet is the migration of deep-sea organisms to the ocean's surface after the sun goes down. Over one million tons of deep-sea organisms make their way to the surface to search for food. Some graze on the phytoplankton in the darkness while others are predators that follow and hunt on the grazers. At dawn these organisms migrate back into the ocean depths.

Why do grey whales migrate such great distances?

They migrate from their breeding grounds in Mexico up to the Artic every year in search of food.

What was the incentive for European voyages in the 15th Century?

Trade with east Asia was the biggest incentive for European voyages in the 15th Century after the land trade route had been cut off when the Turks conquered Constantinople.

What do Tuna eat and what eats them?

Tuna eat the plankton feeding fish that live by seamounts and then larger fish like sharks (silky sharks in the movie) come and eat the tuna.