How carbon-absorbing kelp forests that fight climate change could regrow along California coast with reintroduction of sea otters – they prey on pests that eat the algae
- After a disease wiped out their main predator, sea urchins devastated coastal kelp forests, which absorb more carbon dioxide than California’s redwood trees
- Sea otters, which eat urchins, could help restore balance to the marine ecosystem if they were reintroduced to coastal waters, allowing the kelp to regrow
Kelp forests are a crucial California marine ecosystem. From kelp’s floating canopies to its “holdfast” roots, the giant seaweed – algae, actually – supports greater biodiversity and sequesters more carbon than a grove of redwood trees, while also protecting the American coastline from the full force of Pacific storms.
Kelp forests shelter fin fish, shellfish, whales, seals, octopuses and sharks – more than 1,000 animal and plant species in all.
Since 2013, though, the California’s kelp beds have been in an unprecedented state of collapse. North of the Golden Gate Bridge more than 95 per cent of the kelp is now gone. Warming oceans, combined with past hunting and fishing practices, upset the balance between predators and prey in the kelp forest, with devastating effects.
One possible remedy has a satisfying twist – the return of the sea otter, the keystone kelp forest predator, to its historical range along the state’s north coast.
Perhaps 300,000 sea otters once thrived along the north Pacific Rim, from Japan to Baja California, until humans hunted them almost to extinction in the 19th century.
They’ve rebounded since they were fully protected in the United States 50 years ago, and in California they’ve recolonised about 13 per cent of their range, especially in and around Monterey Bay.