Brynn 8 - Science Unit E

Potable Water

Water that is safe and healthy to drink.

Reservoir

Artificial lakes created to store water.

What portion of the Earth’s surface is covered with water?

74\% of the Earth's surface is covered with water.

Where is most of the fresh water on Earth?

Most fresh water is trapped in frozen icebergs and glaciers, making up about 69.5\% of all fresh water on Earth.

How much drinking water on Earth is available for humans?

Only about 0.003\% of Earth's total water is available for humans to drink.

If all the water on Earth represented by a 1000 L tank, how many milliliters (mL) of that would be available for humans to drink (potable water)?

Only 30 mL of water from a 1000 L tank would be potable for humans to drink.

Where is most of the fresh water on Earth? Is it easy for humans to use? Why or why not? How much of all the water on Earth is available for humans to drink?

Most fresh water is in ice (glaciers). It's not easy to use because it's locked in ice and would take a long time to melt and access. Only 0.003\% of all Earth's water is available for us to drink.

Earth’s population is growing. Do you think we will have enough drinking water for future generations? Why or why not?

Yes, I think we will find effective ways to save water and discover new sources or purification methods. This will make more water available for future generations.

Water quality

Describes how clean and pure the water is, and if it's safe to use.

Salinity

The amount of dissolved salts in water.

Hard water

Water that contains a high concentration of minerals, mostly calcium and magnesium.

Distillation

A method to separate solutions by boiling and then condensing the steam back into liquid, leaving impurities behind.

Reverse osmosis

A method used for purifying water that forces water through a special filter (membrane) that blocks dissolved salts and other substances but lets pure water pass.

How can you determine water quality?

You can determine water quality by measuring the amount of different substances (other than pure water) that are dissolved or present in a water sample.

Where is most fresh water locked up?

Most fresh water is locked up in frozen ice, like glaciers.

How does the salinity of freshwater and saltwater compare?

Saltwater, like ocean water, has a much higher amount of dissolved salts than freshwater. Oceans collect more salts over time due to their size and geological activity, while freshwater sources like lakes and rivers have less.

Hard water contains a high concentration of which minerals? How might you be able to tell if you have hard water? What do you think soft water is?

Hard water contains a high concentration of calcium and magnesium. You can tell you have hard water if it leaves mineral deposits (like white residue) on fixtures, or if soap doesn't lather well. Soft water is water with very low concentrations of these minerals.

What are some items that drinking water is tested for?

Drinking water is tested for:

1. Taste and odour

2. Turbidity (cloudiness) and colour

3. Toxic substances and other pollutants

4. Bacteria

5. Hardness or mineral content

6. pH (how acidic or basic the water is)

7. Dissolved oxygen

8. Solids, including floating materials

9. Dissolved solids

Describe distillation as a procedure for producing fresh water from salt water.

Water with minerals is heated, causing the fresh water to evaporate into steam. This steam is then cooled and condensed back into pure liquid water, leaving the minerals behind.

Describe reverse osmosis as a procedure for producing fresh water from salt water.

Salty water is pushed through a special filter or membrane. This filter has tiny holes that allow clean water molecules to pass through but are too small for salt particles and other minerals, leaving them on the other side.

Where do most cities and towns get their drinking water from? How do they ensure this water is safe for human use?

Most cities and towns get their drinking water from nearby lakes, rivers, or underground sources (groundwater). To make sure the water is safe, they treat it by filtering out particles, disinfecting it (often with chlorine) to kill harmful bacteria, and regularly testing its quality.

Diversity

Description of the variety of different species in an ecosystem; may also be used to describe variety in a population or species.

Adaptation

A physical characteristic or behaviour of a species.

What is one indicator of a healthy aquatic environment? Explain.

There would be lots of animals and aquatic life. If the aquatic environment is healthy, there would be more animals and plants living in the water.

Describe the diversity you would find in a pond by SAB?

The pond that we went to had no animals, so that means the diversity is very low. Around the pond and in it too, there were some plants and weeds.

What is an ecosystem? Why is the diversity of living things in salt water greater than in freshwater? Give as many reasons as you can think of.

An ecosystem is where biotic and abiotic organisms interact with each other. The diversity of living things in salt water is greater than freshwater because saltwater ecosystems are bigger than freshwater ecosystems and saltwater habitats are deeper and can carry a wide range of different plants and animals in them.

Refer to Figure 3.3 in your textbook on page 375. Describe the type of organisms that live in the upper, middle, and lowest zones of a lake.

1. Upper zone: Plants here might include bulrushes and water lilies. You might see small fish, clams, insects, snails, worms, leeches, and frogs.

2. Middle zone: Open water area that still has light penetration. Phytoplankton are food for the fish that live there. Fish move between the middle zone and the darker, deeper water of the lake.

3. Lowest zone: The deepest water of the lake. No light penetrates in this zone, so no plants live here. Food for the fish and other animals that live here comes floating down as waste from the plants and animals that live near or on the surface.

Estuary

of the most diverse and richest ecosystems. Fresh water from rivers and streams mixes with the salt water of the ocean to form brackish water.

What are some adaptations that aquatic species must have? Give an example of one.

If animals are deep in the water, they would have to adapt to no light and not go up for air because they would be too far down to go up for air. They would have to adapt to those things because in the lowest zone, there would be no light penetration.

Describe each of the environmental factors that lead organisms to develop certain adaptations in the chart below (using pages 378 – 380 of your textbook).

1. Intertidal Zone: Plants and animals that live along the shoreline have to be able to withstand the pounding waves and live out of the water during low tide. Different ecosystems can form depending on the type of shore.

2. Estuary: One of the most diverse and roughest ecosystems. Where freshwater and saltwater mix, it is called brackish water. Here, marshes grow, and different kinds of plants, animals, and insects learn to adapt to this environment. There is a rich bird life here because of the abundance of food and shelter.

3. Continental shelf: This is the land that extends out from the edge of the continent below the ocean's surface. Here water is warmer because light penetrates through to the bottom. A variety of plants and animals live in this area.

4. Oceanic Zone: This is the area that extends beyond the continental shelf to the deepest parts of the ocean. Much of this water receives no light, and there is less oxygen due to fewer plants growing in this area. Animals can range from microscopic in size to the largest mammals. Animals in the upper part feed off of phytoplankton. Other animals include fish, jellyfish, shellfish, squid, octopus, shrimp, sharks, etc. Like lakes, animals living in the deepest parts are typically bottom feeders as well as feed off each other.

Population

A group of organisms of the same species that live in a particular area.

What might a change in a population indicate? Why does the population change?

There are a number of reasons why there may be a change in the population sizes. There are three major types of changes to populations:

1. Seasonal: Some organisms become dormant and hibernate during colder seasons and flourish in warmer weather. Others rely on the amount of stagnant water for eggs to hatch.

2. Short-term changes: These are changes in populations that take place over a short period and don't last very long, often due to natural events, drought, or human activities.

3. Long-term changes: They may also be a result of natural causes or human activities. A landslide might change the course of a stream causing some plants to die from lack of water. Also, lionfish have no known predators.

The zebra mussel population in the Great Lake has exploded. Do you think that this population growth will continue in the same way? Why or why not?

The population will at some point taper off due to food sources. If food sources become scarce, then there will be competition for food and in turn, drop the population.

What is a “dead” lake?

A dead lake is a lake that has no living organisms or animals in the water so it looks clean and clear but it is not.

What causes an algal bloom? How does it contribute to a decrease in fish population?

Manure and pesticides cause algal bloom. It contributes to the decrease in fish population because the algal bloom covers the top, which blocks the sun, and the lake doesn't get enough light and oxygen so all the animals and organisms in the water die.

Intertidal zone

Plants and animals that live along the shoreline have to be able to withstand the pounding waves and live out of the water during low tide. Different ecosystems can form depending on the type of shore.

Continental shelf

The land that extends out from the edge of the continent below the ocean's surface. Here the water is warmer because light penetrates through to the bottom. A variety of plants and animals live in this area, such as coral reefs and fish.

Oceanic zone

This is the area that extends beyond the continental shelf to the deepest part of the ocean. Much of this water receives no light and there is less oxygen due to fewer plants growing in this area. Animals can range from microscopic to larger mammals like blue whales. Animals in the upper part feed off of phytoplankton. Other animals can include fish, jellyfish, squid, octopus, shrimp, sharks, etc. Like lakes, animals living in the deepest parts are typically bottom feeders as well as feed off each other.