When a body of water becomes acidified, the first aquatic species to disappear are generally:

The disappearance of aquatic species due to water acidification is a significant ecological concern, and the correct choice highlights the sensitivity of specific species to changes in pH levels.

Freshwater shrimp are considered among the first species to be affected by acidification. This occurs primarily because these organisms have a lower tolerance for pH changes compared to others in the aquatic ecosystem. Acidification directly impacts freshwater shrimp by affecting their reproductive mechanisms and overall physiological health. They are often key indicators of water quality, and their early decline can signal broader ecological imbalances.

While other species like bacterial decomposers, phytoplankton, and fish also exhibit responses to acidification, their tolerance varies. For example, bacterial decomposers can often withstand a range of conditions, phytoplankton might persist longer because they can adapt, and fish may also show resilience in the face of gradual pH changes before experiencing significant impacts. Thus, the sensitivity of freshwater shrimp to acidified conditions makes them the first group likely to disappear in such scenarios.