Passage:
For decades, conservation biologists asserted that the primary driver of declining kelp forest ecosystems along the Pacific coast was elevated sea surface temperatures resulting from climate shifts. However, recent ecological studies have highlighted the profound impact of sea otter population dynamics on these marine environments. Proponents of the trophic cascade theory argue that sea otters, as keystone predators, regulate sea urchin populations, thereby preventing overgrazing of giant kelp. Skeptics of this ecological model point out that in certain northern coastal bays where otter populations remained robust, kelp beds still experienced severe seasonal die-offs, suggesting that thermal stress remains the decisive factor. Nevertheless, proponents clarify that these localized die-offs occurred exclusively during extreme marine heatwaves that temporarily inhibited kelp nutrient absorption regardless of urchin density. By addressing this apparent anomaly, researchers demonstrated that top-down predator control and bottom-up climatic factors interact rather than act as mutually exclusive forces.
Based on the passage, the author refers to the observation regarding kelp die-offs in bays with robust otter populations primarily in order to:
- introduce an opposing perspective to the trophic cascade theory and explain how proponents address this challenge.Cevap
- Bpresent the central claim of the passage that sea otters have no meaningful effect on kelp forest survival.
- Cprove that thermal stress caused by heatwaves is the sole cause of kelp loss across all coastal ecosystems.
- Dprovide empirical data showing that sea urchin populations expand rapidly when sea surface temperatures rise.