Coral reef assignment

A few questions you may be having

trouble with...

Populations and communities

1. What is a limiting factor?  What are the limiting factors that affect a coral reef? 

2. Choose one organism that lives on or around the coral reef.  If there were unlimited growth of this organism, what would this do to the biotic and abiotic factors in this environment? 

You may represent this information in any way you wish (i.e. a diagram, list, paragraph etc..)

Populations and communities

In the natural world, limiting factors like the availability of food, water, shelter and space can change animal and plant populations. Other limiting factors like competition for resources, predation and disease can also impact populations. If any of the limiting factors change, animal and plant populations change, too.

Populations and communitiesThe best way to answer this is to draw a basic 3 of 4 organism food chain. Select one animal from your food chain and describe what would happen to the organisms above and below that animal if there was a population explosion.

Shark

Yellow tailed wrass

Zoo plankton

Phytoplankton

Specific relationships1. Identify five niches of organisms within the coral reef ecosystem.  Explain these in detail. 

2. What are the roles that organisms play in a coral reef ecosystem? Give at least 10 examples.  Remember to use the terms commensalism, mutualism, predation & parasitism.

Specific relationshipsA niche is the role played by an organism in the natural world.

For example, Wrasses perform the cleaning duties on coral reefs

Specific relationshipsFishes that eat seaweeds and other algae constantly crop the reef of fast-growing seaweeds that could smother coral polyps.Many fishes such as Trevally even “commute” onto the reef from deeper water in search of food or even cleaning

Conservation of coral reefs

1. In what ways can the delicate balance in a coral reef ecosystem be upset?

Are there any ways that we can prevent this?

Conservation: Natural events…

Hurricanes, typhoons, El Niño, coral-eating organisms, and diseases

Sometimes these events can actually help the reef to maintain diversity

For example, hurricane storm waves are particularly devastating for tall, branching corals. However, broken fragments of branching corals can start to grow where they land, creating a new colony. These corals are fast growing and quickly form new reef framework under suitable environmental conditions.

Conservation: PollutionAdds all sorts of unnatural and potentially harmful substances to the reef system including nutrients, pathogens and rubbish.

Rising Sea Temperatures

If the temperature is raised above a critical level, the zooxanthellae leave, causing corals to appear brilliant white. This condition is called “bleached”. Prolonged bleaching can lead to coral death.

Conservation: Global warming…

An increase in carbon dioxide (CO2) in the atmosphere can reduce the ability of corals to form limestone skeletons, slowing their growth and making them fragile.

Conservation: Over fishing…

Fishing selectively takes larger, predatory fish off the reef causing population explosions of smaller herbivorous fish.

When the larger fish become scarce, the herbivorous fish are then targeted by fishermen.

Without the herbivores, seaweeds can over-grow the corals and smother them.

Conservation: Destructive fishing practicesDestructive fishing practices include the use of cyanide to stun fish for capture for the marine aquarium and live fish trades and blast fishing to kill fish for food.

Many organisms are killed in the process and habitats that took thousands of years to build are destroyed.