How do sea otters benefit kelp forests?

Sea otters play a crucial role in maintaining the health of kelp forests primarily through their predation on sea urchins. Sea urchins are known to graze heavily on kelp, and when their populations are unchecked, they can decimate kelp forests, leading to significant ecological imbalances. By feeding on sea urchins, sea otters help control their numbers, allowing kelp forests to thrive. This relationship exemplifies a key aspect of trophic cascades, whereby the presence of a top predator (in this case, the sea otter) has a positive effect on the producer level (kelp). As a result of healthier and more abundant kelp forests, various marine species that depend on kelp for habitat and food also benefit, contributing to overall biodiversity and ecosystem stability.

The other options, while they might suggest potential interactions, do not accurately reflect the primary ecological contribution of sea otters to kelp forest ecosystems. For instance, sea otters do not feed on kelp directly, and while they might play a role in nutrient cycling indirectly, that is not their primary function. Furthermore, although various marine life might find shelter in kelp forests, the otters themselves are not responsible for providing that structure