Phytoplankton performs photosynthesis, blooms under Arctic sea ice

Nov. 19 (UPI) – Phytoplankton, tiny unicellular algae, anchor marine food webs in terrestrial oceans. Now, new research suggests that tiny floating microorganisms play a central role in the functioning of the Arctic marine ecosystem.

For decades, scientists have hypothesized that phytoplankton in the Arctic went dormant during winter and early spring, proliferating only after Arctic sea ice begins to retreat during the summer.

But a new review of the scientific literature on the subject – published Thursday in the journal Frontiers in Marine Science – suggests that phytoplankton continues to perform photosynthesis and bloom under Arctic sea ice.

“There has long been speculation that what was happening under the sea ice in the water column was almost ‘paused’ during the polar night and before the seasonal sea ice retreat, which is apparently not the case.” study lead author Mathieu Ardyna, a postdoctoral researcher at Stanford University, said in a news release.

The new paper, a fusion of several decades of research on algal blooms, suggests that phytoplankton production may be an order of magnitude larger in some places than previously estimated.

Temperatures in the Arctic are warming faster than almost anywhere on Earth, leading to significant reductions in sea ice and, as a result, phytoplankton blooms have exploded.

But the latest findings suggest that phytoplankton has always been abundant in the Arctic.

Researchers uncovered 1950s phytoplankton investigations, conducted during a couple of drifted Arctic expeditions, which documented tiny under-ice blooms occurring under thick ice in the central Arctic.

“I think this fact surprised a lot of us, as the models had suggested that this wasn’t the case,” said Ardyna.

More recent investigations have used a combination of autonomous floats, robotic gliders and remote-controlled underwater vehicles to observe phytoplankton activity under the ice.

Since phytoplankton helps extract CO2 from the atmosphere and oceans, understanding its abundance, distribution, and seasonal patterns is essential for accurately modeling the Arctic’s carbon cycle and how it is likely to be affected by climate change.

“So many questions remain unanswered about this critical period of spring, for many Arctic species, their food or their life cycle,” Ardyna said. “Given the remoteness of the Arctic, one way will surely be to develop more and better autonomous platforms to provide us with valuable information.”