What is one method to assess water quality in aquatic ecosystems?

Testing for dissolved oxygen levels is a crucial method for assessing water quality in aquatic ecosystems because it directly reflects the health of the water and the ability of aquatic organisms to survive. Dissolved oxygen is essential for the respiration of fish and other aquatic life; without adequate levels, these organisms cannot thrive.

Moreover, high levels of dissolved oxygen usually indicate a healthy ecosystem, while low levels can signal pollution or excessive nutrients that lead to algal blooms, depleting oxygen as they decompose. This assessment provides valuable information about the overall health of the ecosystem, making it an essential metric for water quality evaluation.

While other methods like analyzing the presence of invasive species, counting fish populations, and measuring water temperature contribute useful information about the ecosystem, they do not directly measure the qualities that affect the immediate survival of aquatic life as effectively as dissolved oxygen levels do.