Oceanography: UPSC Previous Year Questions (Geography)

Explanation

Option (a) is correct: Red tides occur due to the excessive growth of dinoflagellates, which are single-celled organisms containing pigments that cause the water to appear reddish or brownish. These blooms can be found in estuaries, coastal areas, and even open ocean waters. Red tides can be dangerous to marine life and humans due to the toxins produced by the dinoflagellates, which can contaminate seafood and pose health risks when consumed.

Option (b), (c) and (d) are incorrect:

Sea tides refers to the regular rise and fall of sea levels due to gravitational forces exerted by the moon and the sun, not to algal blooms. Black tides are typically associated with oil spills in marine environments, leading to a dark discoloration of the water. Sea flowers is not a standard term used in marine science to describe algal blooms.