Sea urchins feed on a species-rich ecosystem

For a long time, brown algae or kelp face every crisis away from the Northern California coast, including major heat waves in the ocean, which are usually calm here. Unusually strong heating in 2014 led to a sudden collapse, eventually destroying 95 percent of the region’s original seaweed and replaced by a type of desert that had a vast population of sea chinins. What is it Biologist Meredith MacPherson from the University of California at Santa Cruz and her team in “Communication Biology” report.

Northern California’s kelp forests generally thrive in cold and nutrient-rich waters and form a species-rich ecosystem and a nursery for many species of fish. During El Niño events and other warm phases in the ocean, deepwater growth is prevented, and nutrient-poor, warm conditions dominate, in which brown algae worsen and cover up. Usually brown algae recover quickly and completely.

Starfish have also suffered from large-scale deaths since 2013 due to frequent and strong hot water bubbles in recent years, as well as water over-fertilization in the region. Lack of oxygen made animals more susceptible to disease, causing them to be attacked by bacteria and melted into mucus. However, starfish are the main predators of some sea urchins, which in turn harbor brown algae.