Tennessee Wastewater Operator Practice Exam

Which organism bloom indicates a healthy aquatic environment shortly after a green algae bloom?

1. Rotifers

2. Euglena

3. Zooplankton

4. Bacteria

The correct answer is: Rotifers

The indication of a healthy aquatic environment following a green algae bloom is primarily associated with the growth of rotifers. Rotifers are microscopic, multicellular organisms that play a vital role in the aquatic food web. They typically thrive in nutrient-rich conditions, which can arise after a green algae bloom due to the availability of organic material and nutrients such as nitrogen and phosphorus. As algae die off, rotifers feed on the decomposing organic matter, contributing to the breakdown process and nutrient cycling within the ecosystem. Their presence suggests an active and functioning food web, where primary producers are being consumed and recycled by grazers like rotifers. The healthy population of these organisms indicates a balanced ecosystem capable of recovering from periods of high nutrient levels and associated algal blooms. In contrast to other options, such as Euglena, zooplankton, and bacteria, while they also play important roles in aquatic ecosystems, the specific bloom of rotifers following an algae bloom is a clear indicator of ecological recovery and balance, highlighting their significance as indicators of water quality and ecosystem health.