Ocean Microalgae’s Surprising Adaptation to Climate Change Offers Hope for Ecosystem Resilience

University of East Anglia Research Reveals Microalgae’s Iron-Free Survival Mechanism

In a groundbreaking discovery, scientists from the University of East Anglia (UEA) have found that eukaryotic phytoplankton, also known as microalgae, have adapted to cope with nutrient starvation, which is expected to increase due to warming ocean waters and climate change. This finding holds immense promise for mitigating the adverse effects of environmental changes, including ocean warming and reduced crop productivity.

Led by UEA’s Prof Thomas Mock, an international team of researchers has uncovered that these microalgae, which form a critical part of the marine food web, have evolved a unique mechanism to thrive in iron-poor regions of the ocean. These areas, comprising 35% of the ocean’s surface, traditionally lack the iron necessary for algae growth, similar to nutrient-deficient soils affecting crop growth on land. As global warming leads to reduced mixing of surface waters, these regions face nutrient scarcity.

The research, titled ‘Plastid-localized xanthorhodopsin increases diatom biomass and ecosystem productivity in iron-limited surface ocean,’ authored by Prof Thomas Mock and Dr Jan Strauss, highlights the significance of iron for algae in converting sunlight into food and absorbing carbon dioxide from the atmosphere. However, the team discovered that some microalgae have evolved a novel cellular machinery, akin to rhodopsin proteins found in human eyes, enabling them to utilize sunlight for growth without relying on iron.

Dr. Strauss, who continued the research project, explained that these microalgae can bypass traditional photosynthesis by using a light-driven proton pump for growth. Unlike photosynthetic proteins, this mechanism does not require iron and still synthesizes ATP, the energy currency of cells. This adaptation allows them to thrive in iron-poor surface oceans.

This discovery has broader implications, potentially extending to enhancing crop productivity, which also relies on iron for growth. Prof Mock pointed out that this universal mechanism could be utilized in biotechnology to enhance the productivity of microbes that cannot use light, opening possibilities for various applications, including the production of insulin, antibiotics, enzymes, antivirals, and biofuels.

The research is particularly significant for the Southern Ocean, the largest iron-limited aquatic ecosystem on Earth, which sustains large populations of algae consumers. Prof Mock emphasized the critical role of oceans in the survival of humans and life in general, making this discovery of paramount importance.

The study, published in Nature Microbiology on October 16, 2023, sheds new light on the remarkable adaptability of ocean microalgae in the face of climate change, offering hope for the resilience of ocean ecosystems and the potential for advancements in biotechnology.