Can you imagine thriving in the dark? Humans certainly can’t do that, but some tiny organisms in the Arctic do just that. Organisms like microalgae can exist beneath the thick ice and snow of the frozen Arctic Ocean.
These microscopic plant-like organisms challenge our understanding of life because they perform photosynthesis, a light-dependent process, in almost complete darkness. It’s as exciting as it sounds.
Survival of Arctic microalgae
The ability of small-sized arctic microalgae to photosynthesize in low-light conditions was the focus of a recent international study. Contrary to previous beliefs, researchers discovered that photosynthesis in the oceans can occur in significantly reduced light conditions and at much greater depths.
The magic of photosynthesis
Photosynthesis is the process by which plants convert sunlight into a life-sustaining form of energy. This vital process is fundamental to all life on Earth. Previous studies have shown that photosynthesis requires a certain amount of light—much more than the theoretical minimum required. It turns out we may have been underestimating photosynthesis.
The MOSAiC expedition and arctic microalgae
Data for this study came from the MOSAiC research project, the same project that kept the German research icebreaker Polarstern frozen in Arctic ice for a year in 2019.
Their aim was to study the polar climate and ecosystem according to the rigors of each season. Working under the direction of Dr. Clara Hoppe from the Alfred Wegener Institute, the team focused on studying phytoplankton and ice algae, the main participants in photosynthesis in the central Arctic.
And what they found was eye-opening. Plant biomass accumulation occurred a few days after the polar night, when there was complete darkness for the entire month. This is something that would not be possible without photosynthesis.
Nearly impossible conditions for Arctic microalgae
Here’s a jaw-dropping jaw. Photosynthesis occurred beneath the snowy sea ice. This layer of ice allowed only a tiny amount of sunlight to reach the microalgae—about one hundred thousandth of the amount we experience on a sunny day.
“It is impressive to see how efficiently algae can use such small amounts of light. This once again shows how well these organisms are adapted to their environment,” says Dr. Klara Hoppe.
The success of this study was also proof of the power of interdisciplinary collaboration. Sea ice researchers Dr. Nils Fuchs and Professor Dirk Notz from the Institute for Marine Research at the University of Hamburg helped combine the light measurements with biological data. To do this, specially designed instruments had to be frozen into the ice during the polar night.
Implications for climate change research
The MOSAiC expedition’s findings have important implications for our understanding of climate change. As Arctic temperatures continue to rise, the ecological balance of this sensitive region is being disrupted. The ability of Arctic microalgae to photosynthesize in low-light conditions suggests a resilience that could help maintain primary production even as the ice sheet fluctuates.
This resilience not only supports the local food web, but also has broader implications for the global carbon cycle, as increased algal biomass can affect climate dynamics by affecting the ocean’s ability to absorb carbon dioxide.
Arctic microalgae and the future
Given the exciting discoveries in Arctic microalgae, future research should continue to explore the fundamental mechanisms that allow these organisms to thrive in such challenging environments. Further research could examine genetic adaptations that enable efficient photosynthesis in low light or the effects of different ice conditions on algal productivity.
Understanding these factors will not only enrich our knowledge of Arctic ecosystems, but will also inform conservation strategies aimed at preserving these vital organisms in a changing climate. Interdisciplinary interaction will be necessary to advance this research and apply insights to broader ecological and environmental issues.
“Although our results are specific to the Arctic Ocean, they show what photosynthesis can do,” explains Dr. Klara Hoppe.
This new understanding of the efficiency of photosynthesis suggests that similar processes may be occurring in the dark parts of oceans around the world, thus expanding the potential photosynthetic habitat. The study was published in the journal Nature Communication.
Source: Port Altele
