And until recently, our knowledge of microorganisms in Antarctica was non-existent, where the effects of climate change are arguably the most profound. But a paper published recently in Conservation Biology provides a new snapshot of the changing composition of microorganisms in Antarctica. Professor Belinda Ferrari with UNSW Sydney's School of Biotech & Biomolecular Science and colleagues visited Casey Station in Eastern Antarctica in 2019 to see whether projections made on soils sampled 14 years earlier about the disappearance of microbes thriving solely on chemicals in the atmosphere were correct. They were saddened to find that they were. "These bacteria are really rare," says Prof. Ferrari. "They're the ones that live on trace gases in the atmosphere, but in Antarctica they're actually the dominant microbes." The modeling on soils sampled 14 years earlier used a statistical method never before used with microbes, called Gradient Forest, that's usually used to project animal and plant species' survival into the future based on changing environmental parameters. The model suggested that as the Antarctic desert gets less arid and becomes wetter, the changing conditions favor photosynthetic microbes, or phototrophs—the ones that convert light into energy in the same way plants do—over trace gas chemosynthetic bacteria, which feed on low levels of hydrogen gas present in the atmosphere. And this explains why the chemosynthetic microbes had diminished in numbers. "Because there are no vascular plants in this region of eastern Antarctica, microbes are really important for primary production," Prof. Ferrari says, alluding to the process of creating the organic molecules that are crucial to the food web and the basis of almost all life on Earth. "And so what we predicted will happen is that there will be more phototrophs like algae and cyanobacteria and this will result in a greening effect in... |