The Diversity of Organisms in Salt and Freshwater Systems

 Whether an environment is healthy or not is usually judged by the number and range of species that live in that environment.

Diversity in Fresh and Salt Water

Diversity:

The variety of different species in an ecosystem, may also be used to describe variety in a population or species.

Characteristics of lake zones

Characteristics of ocean zones

Salt water supports more diverse living things than fresh water because of a greater number of different environments. 

• 2/3 of most organisms on Earth spend the majority of their life in salt water!

Estuary:

The end of a river whereby the fresh water of a river begins to mix with salt water of an ocean - this mix is called brackish water (in between salty and fresh water)

Aquatic Adaptations

Adaptation :

Physical characteristics or behaviour of a species that increases the species’ chance of survival in a particular environment.

• All living things have specific adaptations to their environment.

• All living things are continually adapting to their environments.

• Common adaptations are for breathing, feeding, reproduction, and movement.

Adaptations of Organisms in Aquatic Environments

The main environmental factors that lead to adaptations:

• Temperature

• Light

• Pressure

• Salinity

• Water movement 

WRITE DOWN AN EXAMPLE OF AN ORGANISM THAT ADAPTED TO EACH ENVIRONMENTAL FACTOR

Ex. Temperature : bacteria that thrives in hot springs (extremophile) 

CHECKPOINT 1

Populations in Fresh and Salt Water

Population :

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

• Ex. A group of minnows near a dock

• Population numbers affected by birth rate (natality), death rate (mortality), immigration, & emigration

Community:

Populations of different species living in the same area (biotic component of an ecosystem)

• Ex. minnows, snails, algae, bacteria, and aquatic plants all living within the same area

Changes in Populations

A change in population could mean many things:

• An increase or decrease in total population.

• A change in the number of males versus females.

• A change in the number of young versus old organisms.

There are 3 major types of changes:

1.Seasonal changes

• Migration (ex. whales move from equator to north and south poles to find food)

• Warmer temperatures increase insect population (during summer months fish have more food to eat)

2.Short-term Changes

• A sudden change in population that does not happen yearly (ex. algae blooms), it does not last too long (1year)

• May be cause by humans, or nature (algae blooms may be caused by runoff from farms, or occur naturally)

3.Long-term Changes

• A change that does not happen yearly and has long lasting effects (ex. coral bleaching)

• Can be caused by nature - volcano destroys nearby habitat

• Caused by humans - global warming, over fishing, polluting waters

CHECKPOINT 2

Water Quality and Aquatic organisms

• Humans need very pure water

• Most living things do not need as pure water as humans to survive.

• Some organisms have specialized to survive particularly harsh aquatic environments. However, specializing decreases their ability to adapt when there are sudden changes to its environment.

  For example:

  • Acidophile - organism lives in acidic environments

  • Alkaliphile - organism lives in basic environment (starbucks)

  • Halophile - organism lives in a salty environment

  • Thermophile - organism lives in a very hot environment

Bioindicator species:

Species scientists observe to indicate overall quality of water. Some species also indicate certain characteristics of water (ex. pH) 

• Look for the bioindicator species in an environment to judge the health of the ecosystem.

Examples of Water Quality Changes

• Acid rain has been known to increase the acidity of a lake to a point that no living things can survive there anymore, and then becomes a “dead” lake.

• An increase in water temperature can cause algae to increase population, if the population gets too large it could affect other organisms, for instance algae can bloom blocking sun from entering the littoral zone of a lake.

Human Activities Affect Aquatic Environments: How Humans Use Water

The combined waters of Earth are a ‘renewable’ resource.

• The location of the water can change dramatically from year to year.

• Water location can be changes because of nature and human activities.

How humans Use Water

• Humans use water directly and indirectly.

• Human uses of water can have benefits (+) and costs (-) to the environment.

• All life uses water, but humans make the greatest and most diverse use of it.

Top three major types of water use

1) Agriculture – 73% of all water use is used for irrigation to grow crops.

• Important for the economy, and food for people.

  • However, over-irrigation can cause many problems. (ex. Salts dissolved on surface)

  • Fertilizer runoff into nearby streams, lakes, oceans

2) Industry – 22 % of all water use is by industries as:

Different industries use different amounts of water.

1. Thermal-electric power plants are the largest users of water in the industrial sector

2. Tar-sand operations use a lot of water, which is not returned to the environment/water cycle

3. Manufacturing plants (paper/pulp, metal, chemical and plastics industry)

4. Mining operations require large amounts of water to assist in the mining process

Water used by industry can also carry pollutants:

Coolants, solvents, corrosives can affect water in the environment if the used water isn’t cleaned or diluted properly

Question: Do dams have + or – effects on water system resources?

3) Domestic – 5 % of the total water use is in our homes.

Used for the following:

• sanitation

• cleaning

• cooking

• recreational (gardening)

• consumption

Household water sources:

• Many developed countries (ex. Canada, Germany, Japan) have access to clean/safe piped in water.

• Many developing countries (ex. Ghana, Pakistan, parts of China) need to walk to get their water supply.

Measuring Impacts on water quality

Water quality is be impacted by human processes:

1. Air pollution affects global warming which in turn warms the oceans

2. Untreated sewage is dumped directly into nearby water systems

3. Fertilizer runoff from farms increases the growth of algae and creates algal blooms

4. Plastic wastes do not break down and negatively affects living organisms living in water

5. Industrial wastes such as acids, coal ash, metal scraps, and oils pollute water

Monitor:

Observe, check, or keep track of something for a specific purpose.

Environment Canada:

Department of the government of Canada which is responsible for the following:

• Monitors environmental conditions including water quality

• Upholds regulations imposed to prevent negative effects

• Enforces laws passed to prevent problems from happening

Governments require regulation of industries, however it must also consider that regulations can impact the economy which provide jobs, products, and services.

Monitoring to Protect Water Quality

• Town and city water supplies are regularly monitored to ensure it is safe.

• Water technicians test the chemicals and organisms in the water.

• Research scientists also use monitoring to help protect the environment.

Ongoing Monitoring

• Ongoing monitoring of a site helps scientists observe change and determine what specific factors caused things to change.

• Useful to develop regulation and technologies to protect the environment.

Problem Solving Needs more than Science and Technology

• In most cases, environmental problems can not be solved by technology alone.

• Problem solving requires a strong commitment from people, people need to take action, and change their habits

• Problem solving is also economical, money is required to create new solutions to curb pollution, regulate waste, and manage sanitation systems.

The cleaning of the Thames river in London is an example where people demonstrated their commitment to public safety, and then stopped polluting it.

People Working Together

In order to solve environmental problems in the world people, science, and technology must work together.

CHECKPOINT 3

Plastic Island Assignment

Watch the following video and answer the questions on the form below

If the embedded form is not working you can always try this link: Plastic Island Assignment

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