Q28.6-3CC - Campbell Biology

Question

WHAT IF? High water temperatures and pollution can cause corals to expel their dinoflagellate symbionts. How might such "coral bleaching" affect corals and other species?

Step-by-Step Solution

Answer

Coral reefs are essential components of the marine ecosystem that exhibit their growth with the help of dinoflagellates. When dinoflagellates are expelled, it can also prevent to the proliferation of corals. The corals live in association with these corals; when they are absent, the corals die.

Step 1: Corals

Corals are living structures that were once considered non-living. They are essential as they help in the growth of algae that are food to several organisms underwater. They also help prevent floods, strong waves, and erosion by water currents.

Step 2: Dinoflagellates

Dinoflagellates are marine eukaryotic algae that can also be found in other water habitats. These organisms are essential for coral reefs' survival. They also provide food to organisms and help reduce carbon dioxide levels by increasing the oxygen levels in the water.

Step 3: Color bleaching affecting corals

Corals and dinoflagellates exhibit mutualistic symbiotic association in which both of them are benefited. The dinoflagellates produce nutrients through photosynthesis that is used for the growth of corals. In return, the corals produce ammonium ions that are taken up by dinoflagellates. 

When there is a rise in the temperature, the dinoflagellates die due to bleaching, and hence the corals also die. This explains that corals cannot exist without one another. This also causes serious threats to the entire marine ecosystem due to lack of food and increased carbon dioxide levels.