Factors Affecting Aquatic Ecosystems

Aquatic Ecosystems Review Session

Learning Target

The general distribution of life in aquatic systems as a function of chemistry, geography, light, depth, salinity, and temperature.

Draw

Circle where the most biodiversity would be found in the ocean?

​Sunlight

Sunlight reaches the upper 200 meters (650 ft). Below that, little to no light is present.

The sun provides 2 things:

Light à photosynthesis à plants grow.

Heat – Upper ocean à warm.

Range of tolerance

• All organisms have temperatures that are too warm or too cold to support life

• Shallow waters or surface water tend to be warmer due to sunlight

Temperature

Open Ended

Notice the center of this map show warmer waters, why do think that is?

Equator = more direct sunlight; warmer temps

Poles = less direct sunlight; cooler temps

​

Sunlight and Latitude

Depth of Water

Remember, the photic zone is where the sunlight can reach ~200M

As we go deeper in the water

• Pressure increases

• No light/little light present

• Much colder temperatures

Organisms have adapted by:

• Having big eyes

• Some migrate to surface to feed

• Bioluminescent

River input = fresh à decrease salinity near coast

Middle of ocean à high salinity à high evaporation

Salinity is a measure of how much salt is in water

How does Salinity Change in the ocean?

Most species can only live in freshwater or saltwater, not both

•But some have special adaptations that allow them to go back and forth

for Example:  Bull Shark

pH- The measure how acidic or basic

​Ocean water ph is 8.1-8.2 (slightly basic)

•Carbon Dioxide dissolved in water can cause the ocean water to become acidic

•Can damage coral reefs

•Affects the formation of shells (there are microscopic organisms that grow shells too)

•Causes changes in some fish behaviors

Open Ended

What process REMOVES CO2 (carbon dioxide) from the atmosphere? (Hint: Think about the plant processes you have recently learned about in class)

Think! What is the purpose of an aerator in an aquarium?

Is it important to have oxygen in the ocean?

Yes! All marine organisms need oxygen to create energy

• Oxygen is dissolved in the water

• Surface water tends to have more oxygen present due to photosynthesis (remember, O2 is a product of that process)

​What about CO2, nitrogen, and phosphorus?

• CO2 is produced during cellular respiration (increased amounts affect PH)

• N and P are important nutrients for many autotrophs.

  • High concentrations near coastlines because of runoff

​Algae Blooms and the effect on Florida's waters

Proximity to Land

Rivers move materials from land to water

• Nutrients (like Nitrogen and Phosphorus)

• Sediment (like dirt)

• Pollution

Human activities are concentrated closest to land

Multiple Choice

Of the three zones in the pond shown, which would you expect to see little or no photosynthesis

• A

• B

• C

Multiple Choice

Which zone in the pond would you expect the greatest amount of biological diversity?

• A

• B

• C

Multiple Choice

Devonte made the table below during his research on aquatic zones

and living organisms. Based on these observations, which conclusion

could you draw?

• Organisms in the intertidal zone must be able to withstand very

  cold water

• There are no producers in the benthic zone that rely on photosynthesis.

• Organisms in the benthic zone must be able to tolerate large

  amounts of oxygen

• The warm water and abundant sunlight in the nertic zone limits

  the plankton population

Multiple Choice

Recent heavy rain storms have caused the sediment in Lake Okeechobee to become suspended in the water.  The effect of suspended sediment particles in the water will cause a decrease in the amount of light that can penetrate to the bottom of the lake. Sediment particles, being dark in color, readily absorb the sun’s heat energy.  Which of the following is the result of sediment suspension? 

• There will be an increase in the fish population 

• There will be an increase in salinity 

• There will be a decrease in temperature 

• There will be a decrease in plant growth