Zooxanthellae and Coral Flashcards

Questions and Answers

What are zooxanthellae?

Dinoflagellate, unicellular algae that can be free-living or symbiotic.

What are the chemical requirements of zooxanthellae?

CO2, Nitrogen, Phosphorous.

What do zooxanthellae translocate?

Sugars, complex carbohydrates, amino acids, and small peptides.

What percentage of photosynthetic products is transferred to the host by zooxanthellae?

90 percent. Signup and view all the answers

Why do hosts need to control the number of zooxanthellae?

To prevent the overproduction of molecular oxygen, which can lead to the production of toxic free radicals and hydrogen peroxide. Signup and view all the answers

How do corals and jellyfish control rates of photosynthesis by zooxanthellae?

They possess enzymes to remove free radicals and hydrogen peroxide and may adjust their exposure to light. Signup and view all the answers

What do corals provide to zooxanthellae?

A protected environment and compounds needed for photosynthesis. Signup and view all the answers

What do zooxanthellae supply the coral with?

Glucose, glycerol, and amino acids. Signup and view all the answers

What does the coral do with the products supplied by zooxanthellae?

Uses them to make proteins, fats, carbohydrates, and produce calcium carbonate. Signup and view all the answers

How does the relationship between zooxanthellae and coral contribute to the water?

It facilitates a tight recycling of nutrients in nutrient-poor tropical waters. Signup and view all the answers

What are zooxanthellae responsible for?

The unique and beautiful colors of many stony corals. Signup and view all the answers

What is coral bleaching?

When corals expel their algal cells, resulting in a stark white appearance. Signup and view all the answers

What happens to the polyps if they go without zooxanthellae for too long?

Coral bleaching can occur, potentially leading to the coral's death. Signup and view all the answers

What type of relationship do coral polyps and zooxanthellae have?

Mutualistic relationship. Signup and view all the answers

Why do corals require clear water?

Because their algal cells need light for photosynthesis. Signup and view all the answers

Where are reefs generally found?

In waters with low turbidity and low productivity. Signup and view all the answers

What is the interesting paradox about coral reefs?

They require clear, nutrient-poor water but are among the most productive and diverse marine environments. Signup and view all the answers

Study Notes

Zooxanthellae Overview

Zooxanthellae are photosynthetic dinoflagellate algae that reside in coral tissues.
Densities can reach 1-5 million cells per cm² of host tissue.

Chemical Requirements

Essential nutrients for zooxanthellae include carbon dioxide (CO2), nitrogen, and phosphorus.
They can utilize CO2 and nitrogen excreted by coral hosts and absorb inorganic phosphorus from water.

Nutrient Translocation

Zooxanthellae translocate sugars, complex carbohydrates, amino acids, and small peptides to the coral.
This translocation is under biochemical control of the coral host.

Photosynthetic Product Transfer

Approximately 90% of organic material produced by zooxanthellae via photosynthesis is transferred to the coral.

Host Control Mechanisms

Corals manage the number of zooxanthellae to prevent potential toxicity from excess oxygen and free radicals.

Regulation of Photosynthesis

Both corals and jellyfish can neutralize oxygen free radicals and hydrogen peroxide through specific enzymes.
Corals can adjust light exposure for zooxanthellae by expanding or contracting their tentacles, and excess zooxanthellae may be digested or expelled, leading to bleaching.

Mutual Benefits

Coral provides zooxanthellae with protection and necessary compounds for photosynthesis.
In return, zooxanthellae produce oxygen and assist corals in waste removal.

Supply of Nutrients

Zooxanthellae supply glucose, glycerol, and amino acids to corals as products of photosynthesis.

Coral Utilization

Corals convert glucose, glycerol, and amino acids into proteins, fats, carbohydrates, and calcium carbonate.

Nutrient Recycling

The association between zooxanthellae and corals maintains a tight nutrient recycling process, crucial in nutrient-poor tropical waters.

Aesthetic Role

Zooxanthellae contribute to the vibrant colors of stony corals, enhancing their visual appeal.

Coral Bleaching

Stress causes coral polyps to expel zooxanthellae, leading to a stark white appearance known as coral bleaching.

Consequences of Bleaching

Prolonged lack of zooxanthellae can lead to coral death, highlighting the symbiosis's importance.

Relationship Type

The interaction between coral polyps (animals) and zooxanthellae (plants) is mutualistic, benefiting both parties.

Environmental Response

Coral reefs respond to environmental changes similarly to plants due to their association with zooxanthellae.

Water Clarity Requirement

Clear water is essential for coral reefs, facilitating light availability for zooxanthellae to perform photosynthesis.

Habitat Conditions

Reefs thrive in low turbidity and low productivity waters, minimizing suspended material presence.

Productivity Paradox

Although coral reefs require clear, nutrient-poor environments, they are among the most productive and biodiverse marine ecosystems.

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Description

Test your knowledge about the vital role of zooxanthellae in coral ecosystems through these flashcards. Learn about their characteristics, symbiotic relationships, and chemical requirements. Ideal for students studying marine biology.