Science and Technology

Earth and Space Review Notes

Permafrost

Permanently Frozen Soil – soil temperature has been below 0o C for 2 or more years.

Consequences of the melting permafrost:

1. Land above the permafrost sinks or changes shape.

2. Soil is more vulnerable to erosion. Sediments can build up in rivers causing them to

become shallower and impact the wildlife in the river.

3. Landslides can occur from melting soil slipping off the frozen soil.

4. Number and type of plant species may change.

5. Primary production will increase due to warmer weather and increased nutrients.

6. Carbon dioxide and methane are released as frozen matter melts and begins to

decompose. This intensifies the greenhouse effect.

Carbon Cycle

Photosynthesis

Photosynthesis

Respiration

Respiration

Decomposition

Formation of fossil fuels

Sediments

Combustion

Hydrosphere: Catchment Area/Drainage Basin

Catchment area:

The natural slope of the land causes water to flow into rivers and accumulate in larger reservoirs, such as a lake. All the area from which water empties into the same large body of water.

A Watershed divide is the line that separates neighbouring drainage basins -- usually defined by natural high ground, such as a hill or peak.

The impacts of human activity on the waterways in a catchment area:

1. Pollution

2. creating a reservoir or navigation channel

3. irrigation projects

4. Sewer systems

5. draining or filling wetlands

Example, excess fertilizer from a farm can seep into the soil and be washed into a river. The

river is part of a catchment area and downstream of the farm will also be contaminated with the

fertilizer. Locations upstream from the farm will not be affected. Water pollution can therefore

spread hundreds of kilometers from its original source

Ocean Circulation

The water in oceans is in constant movement due to ocean circulation. This is the combination of water movement due to surface currents, subsurface current, and the rotation of the Earth.

Surface currents carry water as deep as 400 m and are caused by wind. They generally move water across the Earth horizontally.

Subsurface currents are caused by the density of water.

Importance of thermohaline Circulation:

moves warm and cold water around the Earth

helps regulate climate by preventing extreme cold at the poles and extreme heat around the equator

Glacier and Pack Ice

Glacier

Pack Ice (Ice Floes)

Formation

Formed as a slow sliding mass of ice is formed on land due to the accumulation of snow on top of it. As the glacier slides, some of the ice gets pushed out its sides and breaks off. It falls into the ocean in large chunks and forms icebergs.

Formed on the surface of the ocean due to cold temperatures which freeze the top layer of the water. As pack ice is formed, the ocean water freezes and salt is eliminated. This increases the salinity and density of the ocean, affecting thermohaline circulation.

Content

Freshwater only

Mixture of Fresh and salt water

Location

On land Mountainous areas and polar regions On every continent

On ocean water

Melting Glaciers

1. Increase in sea level: ice on the surface melts and causes the glacier to slide more

quickly. Pieces of glacier break off, fall into the ocean and these icebergs raise the sea level.

2. Decrease in the reflectivity of the earth’s surface (less of the sun’s rays are reflected back into space)

3. Slowing of Thermohaline Circulation: As the glacier melts, freshwater gets added to the ocean and dilutes the salty ocean water. The water now has less of a tendency to sink (lower salinity) thus slowing the thermohaline circulation.

Melting Pack Ice

Loss of habitat o Animals living in the arctic rely on pack ice for their survival. Global warming,

which has greatly reduced the area of pack ice on Earth, puts pressure on certain species, such as polar bears and seals, due to habitat loss.

Slowing of thermohaline circulation

o As more pack ice melts, fresh water dilutes the salty water, causing a decrease in the density of the sea water. The water has less of a tendency to sink, thus slowing thermohaline circulation. This can affect global climate.

o Decrease in the albedo effect or reflectivity of the Earth surface (Less solar radiation is deflected back into space)

Note: Ocean levels do not increase when pack ice melts.

Greenhouse Effect

o A natural phenomenon which helps keep the air around us warm and stable. The Sun’s rays hit the Earth and are absorbed by the ground.

o The heated ground then emits infrared rays. o Some of these rays pass through the atmosphere, into space. o Some are trapped in the Earth’s atmosphere with the help of gases such as

carbon dioxide (CO2), methane (CH4), and nitrogen oxides (NOX). The greenhouse effect can be intensified by human activities that release greenhouse gases such as burning fossil fuels and large scale farming.

How is Earth’s atmosphere supposed to work?

The presence of gases in the atmosphere like carbon dioxide (CO2), methane (CH4) and nitrogen oxides (NOx)help to regulate the temperature of our planet when they are not in excess from human activity.

Intensification of the Greenhouse Effect

What are the effects of increased combustion? 1. Combustion of fossil fuels causes the buildup

of carbon dioxide in the atmosphere. There is too much carbon dioxide to be properly cycled.

2. Increased greenhouse gasses causes trapping of the sun’s rays in our atmosphere. This causes an increase in temperatures.

What are the effects of increased cattle ranching?

1. Increased methane from cows passing gas Decreased photosynthesis and increased respiration as forests are removed to make room for pasture (places for cows to live)

2. Increased waste to be decomposed by decomposers who produce more methane and carbon dioxide

3. Increased greenhouse gasses causes trapping of the sun’s rays in our atmosphere. This causes an increase in temperatures.

What are the effects of deforestation? 1. Decreased photosynthesis due to the

removal of trees. - Carbon dioxide is not able to be properly cycled causing it to build up in the atmosphere.

2. Increased greenhouse gasses causes trapping of the sun’s rays in our atmosphere. This causes an increase in temperatures.

Renewable and Non-Renewable Energy Resources

Energy Source

Description Renewable/Non-renewable

Environmental impact

Fossil Fuels (lithosphere)

-made from plant and animal residue - burned to produce thermal energy in thermal plants -

Non-renewable The refining and burning of fossil fuels produces atmospheric pollutants, including the greenhouse gases carbon dioxide (CO2, methane (CH4), and nitrogen oxides (NOx).

fuels can also contribute to the production of acid rain.

Nuclear (uranium) (lithosphere)

-radioactive element and exists naturally in the lithosphere. -Nuclear power plants use mined uranium to transform thermal energy into mechanical and electrical energy. - A small amount of radioactive material produces a lot of energy

Non-renewable No atmospheric pollutants are released.

toxic and must be stored safely for hundreds of years.

have a devastating effect.

Geothermal (lithosphere)

- A fluid is circulated into the ground; it is heated naturally by the magma, then brought up to the surface. -The hot liquid can be used to heat homes or its thermal energy can be transformed into electrical energy.

-

Renewable Low atmospheric pollution compared to fossil fuels.

geothermal plants contains sulfur, mercury, hydrogen sulfide, arsenic and ammonia. These chemicals can be released in to the water supply, or the atmosphere through steam.

Energy Source

Description Renewable/Non-renewable

Environmental impact

Hydroelectric

-Hydroelectric power plants use the

renewable

(hydrosphere) movement of falling water to spin turbines which are located inside dams built across a river. -Water falling through a dam spins a turbine that converts mechanical energy into electrical energy. -Hydroelectricity is the main source of energy in Quebec. -

Causes little pollution.

dams often floods large areas of land, affecting the habitat of various plant and animal species.

Wave and Ocean Current (hydrosphere)

-Ocean currents are able to spin underwater turbines, which are similar to wind turbines. The mechanical energy produced by the movement of the buoys and blades can be converted into electrical energy. .

renewable May disturb aquatic ecosystems.

not release atmospheric pollutants.

Tidal ((hydrosphere)

- Electricity can be generated from tides when water from a high tide is collected (sometimes using a dam) and then falls through turbines converting mechanical energy into electrical energy. - A tidal range of 5 m is necessary to use this technology.

-

Renewable Tidal barrages (dams) can interfere with fish migration and can affect water flow and levels Does not release atmospheric pollutants

Energy Source

Description Renewable/Non-renewable

Environmental impact

Solar (atmosphere and other)

As the rays of the sun hit panels containing photovoltaic cells, they cause electrons to flow, creating current electricity.

renewable

atmospheric pollutants.

visual appeal of the landscape.

costly and is limited by the amount of sunlight present. -

Wind (atmosphere and other)

-The wind causes the turbines to rotate and a generator converts the mechanical energy into electrical energy. - Wind energy cannot be stored; therefore it needs to be used in conjunction with another source of energy. - Wind energy can be unreliable and unpredictable.

renewable Does not release atmospheric pollutants.

produce sound pollution.

visual appeal of the landscape.

with the wind turbines.

Note: All of these technologies produce electricity by converting mechanical energy into

electrical energy except the technology associated with solar energy