Here, the sea otters plays a critical role in restoring kelp beds that disappeared along the west coast of the U. S., by eating the urchin whose keystone sunflower sea star (24-arm starfish) predators had disappeared due to a 2013 marine heat wave, leaving the urchins free to devour all the kelp. Endangered whales’ digested by-products fertilize phytoplankton, the source of food on which all sea life depends. The shark regulates sea life populations, preventing their overfeeding in concentrated areas (such as groupers over-feeding on critically-needed herbivores that clear algae from coral reefs). The rain in the background does not reach the ocean or the ground, increasingly evaporating due to warmer climate, decreasing moisture availability in earth’s many regions.