Microalgae Use Light-Responsive Protein to Thrive Amid Global Warming

October 20, 2023

Microalgae, which play a crucial role in the marine food chain and carbon dioxide capture, have been found to utilize a unique strategy to cope with global warming, according to a recent study published in the journal Nature Microbiology. As climate change reduces the availability of nutrients in the ocean, these marine microalgae activate a protein called rhodopsin, related to the human eye’s low-light vision protein. Rhodopsin helps microalgae thrive by utilizing sunlight instead of traditional chlorophyll when nutrients are scarce.

Impact of Global Warming on Ocean Nutrients

As global warming warms the surface waters of the ocean, there is less mixing with nutrient-rich deeper waters. This results in nutrient scarcity in the surface layers, affecting primary producers like microalgae.
Reduced nutrients lead to decreased food production and carbon dioxide capture by microalgae, similar to reduced crop yields on land when iron- and nitrogen-rich fertilizers are scarce.

The Role of Rhodopsins

Researchers cloned rhodopsins in the lab and confirmed that they capture light to generate energy (adenosine triphosphate or ATP) – the energy currency of all cells.
Rhodopsin transcripts were found to be more concentrated in low latitudes, where ocean waters mix less and nutrient concentrations are lower.

Harnessing Sunlight for Growth

Microalgae require sunlight to produce food and remove carbon dioxide from the atmosphere, but they also need a significant amount of iron. Approximately 35% of the ocean’s surface lacks sufficient iron to support algae growth.
This is especially relevant in the iron-limited Southern Ocean, home to diverse marine populations like krill, fish, penguins, and whales, all dependent on primary producers like microalgae.

Potential Applications and Benefits

The study’s findings may help mitigate the negative effects of changing environmental conditions, such as ocean warming and reduced crop productivity.
This mechanism could also be employed to enhance the activity of microbes that do not use light, opening possibilities for biotechnological applications, including insulin production, antibiotic development, enzyme production, antiviral drugs, and biofuel production.

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