Final answer:
Coral reefs and kelp forests experience a decrease in biodiversity due to the loss of coastal wetlands, which filter pollutants and act as nurseries. Increased sediment runoff and chemicals, along with climate change factors such as warming and acidification, further threaten these ecosystems.
The correct answer to the student's question is (2) They experience a decrease in biodiversity.
Step-by-step explanation:
How are coral reefs and kelp forests impacted by the loss of coastal wetlands? The loss of coastal wetlands can lead to a decrease in biodiversity in both coral reefs and kelp forests, Wetlands serve as a critical buffer, absorbing pollutants and sediments that would otherwise flow into marine ecosystems. Without this natural filtration system, clearer waters become clouded, which can suffocate corals and obscure the sunlight necessary for the kelp to photosynthesize. Additionally, wetlands serve as nurseries for many marine species that later populate coral reefs and kelp forests. The loss of wetlands disrupts these lifecycles, further reducing biodiversity.
Furthermore, the increase in runoff of sediment and agricultural chemicals due to human activity exacerbates the decline of coral reef and kelp forest ecosystems. Decreased water quality, combined with overfishing and climate change impacts such as ocean warming and acidification, threatens the delicate balance sustaining these habitats. As a result of these multiple stressors, coral reefs and kelp forests face significant threats to their sustainability and resilience.