Kelp forests in Alaskan waters support numerous species of fish and invertebrates.Giant kelp, the dominant producer in these communities, can be completely decimated by the grazing of sea urchins, which consume the kelp and create "urchin barrens" devoid of marine life.Urchins are a preferred food of sea otters.By keeping urchin numbers low, otters help ensure the viability of the kelp forest community.The first response to removal of sea otters from this community would likely be
A) extinction of the kelp forest community.
B) formation of a coral reef community.
C) formation of an ecological community with increased efficiency.
D) initiation of a trophic cascade that increases kelp abundance.
E) initiation of a trophic cascade that decreases kelp abundance.

Question

Quizplus · Accepted Answer

The removal of sea otters, which are predators of sea urchins, would lead to an increase in the sea urchin population. This increase in sea urchins would result in more kelp being consumed, thereby decreasing the abundance of kelp in the ecosystem. This is an example of a trophic cascade, where the removal of a top predator leads to cascading effects through the lower levels of the food web.

Kelp Forests in Alaskan Waters Support Numerous Species of Fish