The bottom of the Arctic blooms too...

During spring the Arctic Ocean blooms with surface waters spread with microscopic algae every year. Once bloom has used the nutrients on the surface, these plankton sink to the seafloor and die or remain in a stable state was what was generally thought, but a new study in ‘Global Change Biology’ has uncovered that in the summer, phytoplankton could bloom at the bottom of the Arctic. 
During summer of 2016, Takuhei Shiozaki, coauthor of the study and a researcher at the University of Tokyo, along with his colleagues were taking routine samples and measurements in the Chukchi Sea. Shiozaki found that instead of being in a stable state with low productivity, algae in water samples from the seafloor showed high primary production, indicating a bloom. 
The effects of climate change are especially severe in the Arctic, causing the region to warm at a rate nearly 4 times as fast as the rest of the planet. Many marine areas that used to be covered by ice year-round are now ice-free in the summer.  
Shiozaki and his team speculated that this lack of ice, coupled with seasonally transparent water and increases in the amount of solar radiation absorbed (irradiance), allows sunlight to reach the bottom of the ocean in shallow areas, triggering phytoplankton blooms. 
To support their hypothesis, the research team returned to the Chukchi Sea to take more samples. They also conducted a lab experiment, re-creating seafloor temperature and light conditions, and incubating sediment samples for 24 days with seawater filtered for organisms. Microscopic algae bloomed in the samples, even when irradiance was only 1% of what is normally found on the surface. 

Aruna Gaitonde, Editor in Chief of the Asian Bureau, Rough&Polished