Survival mode: Adaptability of phytoplankton in the changing Arctic Ocean
发布时间: 2020-01-19 21:03

Kate Lewis, a researcher at Stanford University studying the Arctic Ocean, laughed as she recalled what her mother said: “I don’t understand why you wouldn’t rather work in the tropics.” After all, working in such a barren, cold locale as the Arctic seems a bit odd to most people. But to Lewis, it is a critical environment to understand.

The Arctic is warming two to three times faster than the global average, experiencing dramatic changes. In the summers of 2010 and 2011, researchers on the ICESCAPE (Impacts of Climate change on Eco-Systems and Chemistry of the Arctic Pacific Environment) field expeditions discovered the largest phytoplankton bloom ever recorded, and surprisingly, under thick sea ice in the Chukchi Sea long before their expected arrival. “This discovery was completely remarkable,” Lewis said. The general assumption had been that Arctic phytoplankton blooms—rapidly accumulating phytoplankton—flourish once sea ice melts because these microscopic algae function like any other plant: they need sunlight and nutrients to grow and reproduce. “So it was really shocking to see a massive bloom beneath the sea ice that was more productive than any bloom that had ever been recorded up there,” Lewis said.

Phytoplankton fuel the Arctic food web, affecting the entire marine ecosystem. A shift in the timeline of phytoplankton’s peak production can impact the fish, zooplankton, and migratory animals like whales and birds that feed on it. When these animals miss the arrival of phytoplankton, the food web is disrupted and an insufficient food supply ripples up the chain, including the fisheries many Alaskan communities depend on.

While Lewis was not on the 2010 and 2011 ICESCAPE missions, in 2013, she joined the subsequent mission called SUBICE, or the Study of Under-ice Blooms in the Chukchi Ecosystem. With the support of National Snow and Ice Data Center (NSIDC) sea ice concentration data, the team of researchers tried to catch the under-ice bloom again and understand the survival mechanisms at play in this dark, harsh place.