Sixty years ago, Tasmania’s coastline was cushioned by a velvety forest of kelp so dense it would ensnare local fishers as they headed out in their boats. “We speak especially to the older generation of fishers, and they say, ‘When I was your age, this bay was so thick with kelp, we actually had to cut a channel though it,’” says Cayne Layton, a postdoctoral research fellow at the Institute for Marine and Antarctic Studies at the University of Tasmania. “Now, those bays, which are probably at the scale of 10 or 20 football fields, are completely empty of kelp. There’s not a single plant left.” Since the 1960s, Tasmania’s once expansive kelp forests have declined by 90% or more. The primary culprit is climate change: These giant algae need to be bathed in cool, nutrient-rich currents in order to thrive, yet regional warming in recent decades has extended the waters of the warmer East Australian Current into Tasmanian seas to devastating effect, wiping out kelp forests one by one. Warming waters have also boosted populations of predatory urchins, which gnaw on kelp roots and compound the loss. Tasmania isn’t the only site of destruction. Globally, kelp grow in forests along the coastlines of every continent except Antarctica; most of these are threatened by climate change, coastal development, pollution, fishing and invasive predators. All of this matters because these ecosystems provide huge benefits: They cushion coastlines against the effect of storm surges and sea level rise; they cleanse water by absorbing excess nutrients; and they also slurp up carbon dioxide, which can help drive down ocean acidity and engineer a healthy environment for surrounding marine life. These forests — which in the case of the giant kelp species that grows in Tasmania, can reach heights of 40 meters (130 feet) — also provide habitat for hundreds of marine species. Having spent years studying these benefits, Layton is now trying to bring a patch of Tasmania’s struggling kelp forests back to life. Every few weeks, he dives out to inspect three 12-by-12 meter (39-by-39 feet) plots he’s created off the coast, … Continue reading Can the forests of the world’s oceans contribute to alleviating the climate crisis?