Expert explains phytoplankton's effect on climate change at Rotary Club meeting


Microscopic phytoplankton in the Arctic is essential to our daily life, according to Zachary Brown, who recently earned his doctorate in environmental earth system science from Stanford University. Brown discussed “Arctic Climate Change” at the Oct. 22 Rotary Club of Los Altos meeting.

“We wouldn’t be here without (phytoplankton),” said Brown, who has trekked via foot and kayak approximately 2,300 miles from Stanford up the Pacific Coast to Gustavus, Alaska, his hometown.

There, in the wilderness of southeast Alaska, he serves as executive director and founding member of the Inian Islands Institute, a nonprofit organization devoted to the education of environmental leaders. He continued north on his journey to study how changing sea ice affects the marine biological communities of the polar regions.

Brown joined a team of researchers for a chilly month aboard the U.S. Coast Guard’s research icebreaker Healy, the country’s primary vessel for Arctic marine research. The cutter’s $30,000 per day operating cost confirms the importance of its mission. A traditional “Davy Jones” hazing during his Arctic Circle crossing, Brown said with a smile, transformed him from a “blue nose” into a “polar bear.”

The team deployed equipment to collect water samples in 140 locations at various depths under the sea ice. Brown filtered out the phytoplankton and analyzed the amount of carbon dioxide and chlorophyll present at each location.

Phytoplankton form the first link in the marine food chain, Brown noted, feeding tiny marine animals called “zooplankton,” which feed bowhead whales, which feed the Inuit native peoples, which eventually sometimes feed polar bears.

The team also deployed a meteorological station on the sea ice, but, Brown said, a polar bear promptly destroyed it.

Phytoplankton are microscopic plants – some with “beautiful, ornate, glassy shells,” Brown said, that absorb or draw down atmospheric carbon dioxide. While photosynthesizing, they emit oxygen byproducts, thus increasing the breathable oxygen in the atmosphere. Like tiny biological pumps, he explained, they take carbon dioxide from the ocean’s surface and carry it down to deeper waters.

Typically, phytoplankton’s bloom is most prolific at the very edge of the ice because both sunlight and nutrients co-exist there in the right balance.

Brown’s team made a new discovery: In the warming Arctic climate, phytoplankton populations are now thriving directly under the sea ice, as far as 150 kilometers away from the ice edge. The hilly, icy landscape has become “pancake flat,” he said, thin and covered with surface melt ponds in some areas. It’s important, Brown added, because the dense under-ice blooms of phytoplankton may disrupt marine food webs.

The polar regions are warming at a much faster rate than the rest of the planet, warned Brown, a process known as “polar amplification.” Research show that Arctic sea ice is disappearing before our eyes. In the late 1970s, there were 8 million square kilometers of Arctic sea ice during the summer minimum, a number that has dwindled to 4 million to 5 million square kilometers of ice today.

For more information on Brown’s research, email [email protected] or visit

Marlene Cowan is a member of the Rotary Club of Los Altos. For more information, visit

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