The notion that the ocean floor was already aware of what was about to happen is subtly unnerving. A microscopic organism that lives almost a thousand meters below the sea surface appears to have been adjusting, recalibrating, and preparing while climate summits have dragged on for decades and carbon pledges have been made, broken, and remade. Not because it recognized the danger. However, it didn’t have to in a biological sense.
Nitrosopumilus maritimus is the name of the unglamorous microbe in question. It lacks the visual appeal of a polar bear on a receding ice shelf or a bleached coral reef. Living in cold, dark, iron-poor water where most life would struggle to survive at all, it is invisible to the human eye. However, the fact that this organism and its relatives account for about 30% of all marine microbial plankton should stop anyone in their tracks. Researchers at the University of Illinois Urbana-Champaign are now characterizing a group of microorganisms that make up nearly one-third of the ocean’s microbial population as surprisingly well-suited to the precise ocean conditions that climate change is bringing about.
The study, which was led by microbiologist Wei Qin and USC’s David Hutchins and published in the Proceedings of the National Academy of Sciences, discovered something that challenges the conventional narrative of ecological collapse. The microbes did not disintegrate when scientists subjected pure cultures of Nitrosopumilus maritimus to higher temperatures and lower iron concentrations, which are increasingly occurring in deep ocean waters. They adjusted. Their need for iron decreased. They became more productive. It’s the kind of discovery that causes you to reevaluate which organisms are truly concerning.
Deep ocean waters were thought to be largely shielded from surface warming due to their sheer depth for a long time. That presumption is being undermined. According to Qin, warming effects could reach depths of 1,000 meters or more, indicating that the biological and chemical conditions there are changing in ways that we are just now starting to detect. It’s amazing that these archaea seem to have been subtly programmed for precisely this situation, decreasing their reliance on iron at the exact moment when it becomes more scarce.
This has far-reaching implications beyond the lab flask used for the experiments. Because they transform ammonia into different forms of nitrogen that control plankton growth, these microbes are essential to the ocean’s nitrogen cycle. In turn, plankton serves as the foundation for nearly all marine food chains that are worth discussing. Destabilization of archaea populations would have far-reaching effects on ecosystems that are genuinely hard to simulate.
Reading this research gives me the impression that nature has been practicing for situations that people are still unaware of. With a group of about 20 scientists, Qin and Hutchins are organizing a research expedition on the ship Sikuliaq, which will sail from Seattle toward the Gulf of Alaska and ultimately the subtropical gyre. They wish to compare these lab results to the actual, untidy conditions of the open ocean. It’s still unclear if what works in controlled experiments holds true when heat, changing chemistry, and shifting currents all happen at once in the ocean.
The irony that permeates all of this is difficult to ignore. The most biologically intelligent organisms appear to be handling the situation with the least amount of cognitive ability. Timelines are still a topic of debate among humans. In the meantime, something tiny and ancient has already begun to adapt as it sits in almost complete darkness at the bottom of the Pacific.
