D. a dam that has been built upstream
The construction of a dam upstream can disrupt the flow of water, alter nutrient cycling, and affect the overall health of the river ecosystem. This can lead to chemical imbalances, changes in aquatic populations, and poor nutrient cycling as described in the scenario.
Ecologists from Spain are noticing chemical imbalances, changes in aquatic populations, and poor nutrient cycling in the river that runs through their country. Which of the following is the MOST likely cause of these issues?
A. pesticides that have entered oceans
B. runoff from high rainfall
C. an oil spill in a local river
D. a dam that was been built upstream
1 answer