APES Air Pollution Practice Test

Rising ocean temperatures have a significant impact on marine ecosystems, with coral bleaching being a particularly critical consequence. Coral bleaching occurs when corals, which are sensitive to temperature changes, expel the symbiotic algae (zooxanthellae) that live within their tissues. These algae provide essential nutrients through photosynthesis and give corals their vibrant colors. When water temperatures rise beyond a coral's tolerance threshold, the stress causes them to expel the algae, leading to a loss of color and, more importantly, vital nutrients. If conditions do not improve, this can lead to coral death and significantly affect the biodiversity and health of marine environments, as coral reefs support a diverse range of marine species.

The other possibilities, while they relate to climate or ocean changes, do not accurately reflect the direct consequences of rising ocean temperatures. Sea levels are primarily affected by melting ice caps and thermal expansion of water, not directly decreased by rising temperatures. Reduced atmospheric pressure is more related to weather patterns rather than temperature itself. Finally, the amount of precipitation is influenced by numerous climatic factors but is not directly linked to ocean temperature in a straightforward manner. Thus, coral bleaching stands out as the most direct and significant impact of rising ocean temperatures.