Increased atmospheric carbon dioxide negatively affects coral reefs by: select one: a. increasing photosynthesis by symbiotic algae. b. decreasing photosynthesis by symbiotic algae. c. increasing acidity of ocean water. d. decreasing acidity of ocean water.

Increased atmospheric carbon dioxide will diffuse to the ocean water (since normally, there is lower concentration of dissolved carbon dioxide in the ocean water). The dissolved carbon dioxide takes into the form of carbonic acid thereby increasing acidity of ocean water. More often than not, the acidification of ocean water leads to detrimental results especially in marine organisms that are pH sensitive such as coral reefs and many invertebrates.