Bryozoan skeletons in acidic solution

Educational value

• Bryozoans are a type of animal that is useful for studying the potential consequences of changes to ocean acidity. An increase in ocean acidity could affect the formation of skeletons and shells in marine animals. The experiment depicted in the image is testing how the skeletons of bryozoans respond to varying levels of acidity.
• Bryozoans, or 'moss animals', are a group of animals that live in colonies. Each colony may vary in number, from just a few individuals up to millions of animals. Bryozoans eat single-celled algae and form a structure, known as a thicket, in which many other animals such as sea stars and fish take shelter. Bryozoans are one type of marine animal that is likely to be affected by changes to ocean acidity.
• Ocean acidification is the increase in the acidity of the ocean. Oceans absorb carbon dioxide from the atmosphere. As carbon dioxide levels increase due to human activities, oceans absorb more carbon dioxide, which leads to an increase in ocean acidity and a lowered pH.
• Even small changes in ocean pH can have a large effect on marine animals. Many marine animals, such as bryozoans, require calcium carbonate to produce their shells or skeleton. As oceans become more acidic, there is less calcium carbonate present in the oceans.

Year level

5; 6; 7; 8

Topics Acidification pH Experiments