Apex Earth Science 1.3

How do oceanographers study the ocean?

Oceanographers are scientists who study the ocean and its inhabitants. They use a variety of tools, including: thermometers (temperature), hydrometers (salinity – or salt content), CTD (conductivity-temperature-depth), fathometers (ocean depth), and submersible submarines (the ocean bottom).

. Understand the properties of ocean water.

The temperature and salinity of the water determine its density. Cooler water is denser than warmer water so it sinks to the bottom. Salty water is denser than less salty water.

What are the different ocean zones?

epipelagic (sunlit), mesopelagic (twilight), bathypelagic, abyssopelagic, hedalpelagic (midnight zones).

epipelagic zone

The top zone of the ocean, where most of the light from the sun reaches.

mesopelagic zone

middle zone known as the twilight zone due to little sunlight. No plants live here, but there are bioluminescent organisms.

Bathypelagic

Deep zone known as the midnight zone, due to no sunlight. Bioluminescent organisms reside here.

Abyssopelagic

The bottom zone of the open ocean extends to the sea floor. Dark and freezing, very few creatures live here.

Hadalpelagic

This zone is found in deep trenches and canyons. Black, freezing cold, and intense pressure.

Continental Shelf

The submerges, relatively flat land at the edge of a shoreline where a continent meets the ocean crust. A lot of marine life live here

Continental Slope

The steeply sloping land where the continental shelf ends down to the ocean floor.

Characteristic of the Equator

The surface of the water is warmer than the bottom, because the sun’s rays hit there directly. Also, water is warmer closer to the equator than farther north. The water is less dense because it is warm and less salty.

Characteristic of the Poles

Closer to the Poles, sunlight hits at an angle, so the warmth is spread over a wider area. Also the water is dense because it is salty and cold.

How does the sun affect ocean currents, and how do currents distribute heat around the globe?

Warm currents go to the poles from the equator, and cold currents from the poles go to the equator. It redistributes heat across the globe.

Formation of Waves

When wind blows over the ocean's surface, it transfers energy and creates waves.

Crest

top of the wave

Trough

lowest point between two crests

wave height

distance between the bottom of the trough and the top of the crest.

Refraction

The bending of a wave, it drags on the bottom and comes in on an angle crashing onto the shore.

Erosion

When waves hit the shore, they gradually wear it away. Erosion creates sea arches, caves, and stacks

a longshore current

A current that runs parallel to the shoreline

Longshore drift

Sand and sediment from one part of the beach is deposited to another part of the beach

How does the moon effect the tides?

The side of the Earth that is closest to the Moon, the Moon's gravitational force pulls ocean water toward the Moon. On the other side of the Earth, the force of gravity is weaker, the water weighs less and a bulge is created as the water tries to float away. There are two bulges.

Spring Tide

The highest and the lowest tides. This is during a new moon or a full moon when the gravitational pull is highest

Neap Tides

smallest tides. This happens during the first and last quarter of the moon. The gravitational pull cancels out.

Coriolis Effect

the deflection of motion caused by Earth’s rotation that causes moving objects to turn left in the Northern Hemisphere and to turn right in the Southern Hemisphere.

Normal conditions of trade winds

The water in the western Pacific is typically warmer than in the eastern Pacific because trade winds blow the warm waters of the eastern Pacific westward and keep it there. Also, upwelling in the eastern Pacific keeps the water cooler

El Nino

The gradient weakens and the Southern Oscillation causes the trade winds to weaken, and even blow backwards. This pattern reversal leads to unusually wet weather in parts of South America and unusually dry weather in the western Pacific.

La Ninas

Opposite of El Nino, the easterly winds blow stronger.