The Aquatic Ecosystem — Effect of Atmospheric Gases on Aquatic Environments

About this lesson

This unit focuses on the effect of atmospheric air gases, specifically oxygen and carbon dioxide, on aquatic environments. It explains the sources of these gases in water, including atmospheric exchange, photosynthesis for oxygen, and respiration and human activities for carbon dioxide. The text discusses the solubility of these gases in water, noting that solubility decreases with increasing temperature and is lower in saltwater than freshwater. It also details the effects of increased oxygen (supporting respiration, metabolism, activity, and ecosystem balance) and increased carbon dioxide (causing acidification, impairing respiration, and weakening support structures like external skeletons in corals and oysters and internal skeletons in fish). The unit also covers the effects of decreased carbon dioxide, such as reduced photosynthesis and impacts on food chains and pH balance. By the end, students should be able to explain the sources and solubility of these gases, interpret graphs showing solubility versus temperature, and describe the positive and negative effects of gas concentration changes on aquatic organisms.