How does increased temperature typically affect oxygen levels in surface waters?

Increased temperature typically decreases oxygen solubility in surface waters. When water warms up, the ability of water to hold dissolved oxygen diminishes. This phenomenon occurs because gases, including oxygen, are less soluble in warmer liquids. As the temperature rises, oxygen molecules become more energetic and are more likely to escape from the water into the atmosphere, which results in lower levels of dissolved oxygen in the water.

Furthermore, this reduction in dissolved oxygen can have significant ecological impacts, as many aquatic organisms, such as fish and invertebrates, rely on adequate oxygen levels to survive. When temperatures rise, especially during summer months, the reduction in oxygen can lead to hypoxic conditions, where the oxygen levels are insufficient to support most marine life, potentially leading to die-offs or shifts in species populations.