What is one negative impact of sea urchin overpopulation in kelp forests?

The overpopulation of sea urchins in kelp forests leads to overgrazing of kelp, which is a significant negative impact on these ecosystems. Sea urchins are herbivorous grazers that primarily feed on kelp and other macrophytes. When their populations exceed a certain threshold, they can consume kelp at a rate that exceeds the plant's ability to grow back. This results in the deterioration of kelp forests, which are crucial habitats for a wide variety of marine organisms.

Kelp forests provide essential ecosystem services, including habitat structure for fish and invertebrates, coastal protection, and supporting biodiversity. The depletion of kelp due to overgrazing by sea urchins can lead to diminished habitat for marine species that rely on kelp for food and shelter, ultimately disrupting the entire marine ecosystem. Additionally, loss of kelp can affect nutrient cycling and carbon sequestration in these underwater ecosystems.

When assessing the other options, while water clarity may be influenced by phytoplankton or sediment rather than directly by urchin populations, or algal species could see varied growth depending on other environmental factors, the direct impact of sea urchin grazing on kelp is evident. The decline of fish populations can