Unit 5 Hydrosphere (part 2) 

Ocean Exploration:

Divers: Deep sea divers were the first method of exploring the ocean. They go all the way back to the 1800s.

Sonar: Stands for- SOnar Navagtion And Ranging

• A system that sends sounds that measure the distance between objects in the water
• Early American surveyors used ropes and lead weights

Submersibles: Satellites, sonar, and divers only scratched the surface of the ocean. Submersibles alone helped explore the abyssal depths.

• Submersibles helped impose many challenges like pressure.
• The main types are: submarines, ROV (remotely operated vehicles), Underwater Habitats

Benefits of the New Technologies

Parts of the sea Floor: Beneath the world’s oceans lie ragged mountains, active volcanoes, vast plateaus, and almost bottomless trenches.

Mariana Trench: The deepest part of the world’s ocean. It is in the western pacific ocean.

Hydrothermal Vents: Areas of the sea floor where hot water heated by magma rushes out

• Hot springs and geysers on land and hydrothermal vents form in volcanically active areas often on mid-ocean ridges where the tectonic plates are spreading apart.
• Seawater in the hydrothermal vents may reach over 340c
• Vents do not boil because of extreme pressure
• They support complex organisms and have developed unique adaptations to the high temperatures and environmental conditions we would consider toxic

Chemosynthetic Organism: Most of life on Earth depends on photosynthesis, however, at hydrothermal vents the ecosystem has evolved in the absence of sunlight, and its source of energy is completely different: Chemosynthesis.

• Chemosynthesis is the process by which certain microbes create energy derived from chemical reactions
• So animals live around hydrothermal vents to create energy from the chemical coming out.

Vocab

Aphotic Zone: the portion of a lake or ocean where there is little or no sunlight; formally defined as the depths beyond which less than 1% of sunlight penetrates.

Benthic Zone: the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers

Downwelling: the downward movement of fluid, especially in the sea, the atmosphere, or deep in the earth

Estuary: a place where freshwater meets up with salt water: nature’s nursery

Hydrothermal vents: a fissure in a planet’s surface from which geothermally heated water issues

Intertidal Zone: the area of the shore and seabed that it exposed to the air at low tide and submerged at high tide

Neritic Zone: relatively shallow part of the ocean above the drop-off of the continental shelf, approximately 200 meters in depth

Open Ocean: the sunlit top layer of the ocean beyond the continental shelves; the vast bulk of the sea, it covers over 360,00,00 square kilometers of the earth’s surface and is referred to as the marine desert because nutrients are lower here than in the shallow seas; life can be scarce

The Ocean Zones

There are FIVE oceans in total:

1. Atlantic
2. Pacific
3. Indian
4. Arctic
5. Southern

Intertidal Zone:

The intertidal zone sometimes referred to as the seashore, is the area that is above water at low tide and under water at high tide. Animals have to adapt to harsh environments.

Low Tide - The intertidal zone becomes dry from low water levels

High Tide - The intertidal zone becomes submerged in water

Neritic Zone:

The neritic zone is the relatively shallow part of the ocean between the low tide mark and the continental shelf. The neritic zone receives plenty of sunlight with a relatively stable temperature, making it suitable for aquatic plants.

Oceanic Zone:

It is the region of the open sea beyond the edge of the continental shelf where the water measures 200 meters deep, or deeper. It is often difficult for life to sustain itself in this type of environment, but some species do thrive in the oceanic zone.

Photic Zone: Epipelogic (Sunlight) Meters: 0-200

Aphotic Zone: Mesopelogic (Twilight) & Bathypelagic (midnight) Meters: 200-4,000m

Abyssal Zone: Abyssopelagic (The Abyssal) & Hadalpelagic(Trenches) Meters: 4,000 <

Ocean Movement

Ocean Currents move heat, energy, and carbon dioxide around the globe.

An ocean current is a mass of moving water in the ocean surface currents originate from strong winds blowing over the ocean that is set in motion by uneven heating.

Northern Hemisphere - Clockwise

Southern Hemisphere - Counter Clockwise

Upwelling is caused by the wind near the shores. The wind drags water from the deep ocean.

• Pulls nutrients up to surface
• Nutrients increase algae and plant increase
• Large numbers of plants and animals can be found wherever there is upwelling

Downwelling is when cold dense water at the poles sinks down into the deep ocean

• Downwelling is important because it brings oxygen down into the deep ocean
• The deep ocean has NO oxygen production because there are no plants/no sunlight

Deep Currents

Dense Ocean water is by the poles because it is cold. The cold water travels along the ocean floor.

Oceanic Conveyor Belt

The combination of surface and deep currents creates the oceanic conveyor belt.

Ocean Water

Salinity: Is a measure of the amount of dissolved salt in the ocean

Salts: Ocean water is a solution. Sodium Chloride is the main solute

Salt Water Density: Salt water is dense than fresh water

Gasses in the Ocean: Gasses like O2, N2, and CO2 are very important in water just in the air. Ocean plants use up CO2 and release O2. Oceans are known as Carbon Sinks and remove CO2 from the atmosphere.

Resources of the Ocean: Fish and other food sources for eating. Oil deposits have been found around the shores, 30% of the world’s oil is pumped from below the sea floor. Minerals are on the ocean floor and some are iron, cobalt, etc.

Impacts on the ocean:

Overfishing is when people catch fish at a faster rate than they reproduce

By-Catch is fish that are caught by a net but thrown back into the sea.

Ocean Pollution

44% of ocean pollution comes from runoff

33% is from air pollution

12% if from shipping and oil spills

10% if from ocean dumping

1% is from offshore drilling