Scientists unlock secrets of algae’s resilience to climate change

By Jim Leffman via SWNS

A humble algae that forms the base of the ocean food chain has been found to be able to quickly adapt to climate change.

The discovery could lead to a method of countering the negative effects of global warming in the oceans and even producing antibiotics, biofuel and crops.

Researchers from the University of East Anglia studied eukaryotic phytoplankton also known as microalgae, one of the building blocks of ocean life.

Marine microalgae are the base of the largest food web on Earth including krill, fish, penguins, and whales as well as pulling carbon dioxide from the atmosphere and producing oxygen.

Professor Thomas Mock discovered the algae have found a way to cope with nutrient starvation which is predicted to increase due to warming waters.

The breakthrough holds promise for biotechnology developments that could counter the negative effects of global warming, such as an increase in ocean temperatures and even a reduction in the productivity of crops.

Mock said: “For algae to produce food and to remove CO2 from the atmosphere, they need sunlight.

“The dilemma, though, is that the cellular machinery for using sunlight requires a lot of iron.

"However, 35 percent of the surface of the ocean does not have enough iron to support the growth of algae.

“In these areas algal productivity should be much more reduced, similar to crops on land that lack iron- and nitrogen-rich fertilizer, meaning crops will not grow that well.

“Global warming is increasing drought on land and the same thing happens in the ocean: the warmer the surface water gets, the lower the nutrients in these surface water layers because of reduced mixing that usually adds nutrients from the deeper ocean.

"Hence, algae are supposed to starve and therefore produce less food and take up less CO2 from the atmosphere.”

But writing in the journal Nature Microbiology the team says the algae have found a way to cope with nutrient starvation, by evolving an additional cellular machinery that allows them to use sunlight for growth without the need for iron.

Co-author Dr Jan Strauss at the European Molecular Biology Laboratory (EMBL) in Hamburg added: "Some groups of microalgae can circumvent photosynthesis by using a light-driven proton pump to fuel growth.”

The team found that algae use a light-responsive membrane protein that is related to one in human eyes: called rhodopsins.

These proteins do not require iron and one specific group of them pumps protons through membranes, which enables the synthesis of ATP, the energy currency of all cells, which is a main function of photosynthesis in all photosynthetic organisms.

Mock said: “This simple cellular machinery is the reason why they still can thrive in these nutrient-poor surface oceans, and it is therefore also likely they will be able to cope with global warming as they are preconditioned.

"Potentially, the discovery could be used to enhance the productivity of crops, which also require iron for growth. This is universal for all primary producers.

"This machinery can also be used in biotechnology to enhance the productivity of microbes that cannot use light such as yeast.

"We can modify them so that they can use light for growth, which is desirable in biotechnology, such as the production of insulin, antibiotics, enzymes, antivirals and even biofuel.”

The team’s work is particularly relevant for the Southern Ocean, which is both the largest iron-limited aquatic ecosystem and among the most productive, supporting the largest populations of algae consumers.

Mock said: “No other habitat on Earth is more important than our oceans for the survival of humans and life in general.”