Why some of British Columbia’s kelp forests are in more danger than others

By Samuel Starko, The University of Western Australia, Brian Timmer, Christopher Neufeld, University of British Columbia, Julia K. Baum, University of Victoria

Lush underwater forests formed by large brown seaweeds known as kelp are among the most abundant and productive coastal ecosystems in Canada.

Kelp forests help to support fisheries, draw down carbon and improve water quality — in the process contributing billions to the global economy. Unfortunately, climate change is now a major threat to kelp forests. Kelp forests require cool water temperatures, and recent ocean warming has placed these valuable ecosystems in hot water.

In our new study, we highlight by just how much some of Canada’s kelp forests along the Pacific coast have declined. We also show that, despite recent impacts of climate change, kelp forests in some areas have remained stable, offering hope for future kelp forests and shedding light on the drivers of ecosystem resilience.

Marine forests in hot water

The past decade has seen unprecedented warming along North America’s west coast. Beginning in 2014, a string of marine heat waves created warmer-than-usual conditions that have wreaked havoc on a range of ocean species.

Marine heat waves are becoming longer and more intense as greenhouse gas emissions continue. These heat waves are major drivers of oceanic change.

One of these major heat waves also magnified the ongoing seastar wasting disease epidemic, a phenomenon that killed millions of seastars from Mexico to Alaska. Effects of the loss of these voracious predators reverberated throughout coastal ecosystems, triggering a boom in the sea urchins that seastars typically eat. Overabundant urchins consumed large amounts of kelp. Left unchecked, sea urchins can mow down entire kelp forests.

Together, marine heat waves and seastar declines led to devastating kelp forest losses along many parts of North America’s west coast over the past decade. This included declines in Mexico and California.

Read Full Story https://theconversation.com/why-some-of-british-columbias-kelp-forests-are-in-more-danger-than-others-226774