State the type of interaction that occurs between Zooxanthellae and reef-building corals.

State the trophic level of Zooxanthellae.

When coral is bleached, certain organisms become more common in the ecosystem such as the cnidarian Gorgonia, the echinoderm Diadema, other algae and certain sponges. State the term that is used for organisms whose presence provides evidence of the existence of a particular environmental condition.

A coat of algae builds up on coral reefs as a consequence of eutrophication. Explain the relationship between eutrophication and algal growth.

Explain how an excessive growth of algae on coral reefs can be controlled by top-down factors.

symbiosis/mutualism

producers

indicator species

a. eutrophication is nutrient enrichment of a body of water 

b. example of nutrients  eg: nitrates 

c. «nutrients» serve as fertilizer for the algae «promoting growth» 

a. top-down factors refer to predation/herbivory/trophic level above another one 

b. which limit/control population growth 

c. named example of a top-down predator eg: parrotfish. Do not accept general names, like “fish”.