Arctic Coastlines Hitting Ecological Tipping Point
Along rocky coastlines of the Arctic Ocean, a radical change is taking place, perhaps as profound as vanishing sea ice but less evident to the eye. Ecological foundations are shifting, with existing algae replaced by warmth- and light-loving species. It might not seem like much, but algae form the base of ocean food chains, and the change is happening fast.
“The abrupt character of these extensive changes, confirmed by our statistical analyses, provides a convincing case for tipping points being crossed,” wrote researchers led by marine biologist Susanne Kortsch of Norway’s University of Tromsø in an email to Wired.
For scientists, tipping points aren’t just pop-culture shorthand, but refer to a specific type of transition: sudden and non-linear, with one set of conditions snapping into another. In marine settings, that’s been seen in the western Mediterranean, now dominated by jellyfish and invertebrates, and Caribbean coral reefs now overrun by algae. As for the Arctic, they’ve been detected, but mostly on land or in freshwater lakes and swamps.
Kortsch and her University of Tromsø colleagues, including marine biologists Bjørn Gulliksen and Paul Renaud, went to sea, examining the rocky-bottomed subtidal zones of two Arctic fjords in the western Svalbard islands. Researchers have studied those fjords for more than three decades. As Kortsch’s group described August 13 in Proceedings of the National Academy of Sciences, they’ve become a very different place.