What effect does nutrient overload have on wetland ecosystems?

Nutrient overload in wetland ecosystems primarily leads to eutrophication, which can severely disrupt the ecological balance of these environments. This process involves the rapid influx of nutrients, particularly nitrogen and phosphorus, often from agricultural runoff or wastewater. As a result, this excessive nutrient input stimulates algal blooms, where algae multiply rapidly, often forming dense mats on the water surface.

These algal blooms can block sunlight from reaching aquatic plants, inhibiting their ability to photosynthesize and thrive. The decay of large amounts of algae consumes oxygen in the water, leading to hypoxic or anoxic conditions that can result in fish kills and the death of other aquatic organisms. Furthermore, the degradation of water quality impacts the flora and fauna that rely on these wetlands for habitat, food, and breeding grounds, thereby harming overall biodiversity.

In contrast, the other options do not accurately reflect the consequences of nutrient overload. Increased plant diversity and enhanced biodiversity in surrounding areas are generally the opposite of what occurs during eutrophication, as stressed ecosystems become less hospitable to a variety of species. Similarly, nutrient overload does not typically lead to a reduction in invasive species but rather can create conditions that favor their proliferation, compounding the negative effects on the ecosystem.