Rising ocean temperatures, caused by climate change and marine heat waves, are now reaching even the deep ocean. Scientists warn that this warming could disturb the fragile chemical and biological systems that support marine life. These systems are important because they help keep the ocean balanced and healthy.
However, recent research offers some hopeful news. Scientists have discovered that a key ocean microbe may be able to adapt to these changing conditions. The microbe is called Nitrosopumilus maritimus. It lives in seawater and plays an important role in moving nutrients through the ocean. The study shows that this organism can survive in warmer water. It can also live in areas where nutrients are limited. This ability may help it continue its role in ocean ecosystems even as the climate changes.
Because of this ability, researchers believe it could play a key role in how ocean nutrients are distributed in the future as the climate continues to warm, potentially influencing the health of marine food webs and the overall productivity of ocean ecosystems. The findings were published in the journal Proceedings of the National Academy of Sciences.
Scientists believe that a large number of tiny ocean organisms are microbes. One important example is Nitrosopumilus maritimus. Researchers estimate that microbes like this may make up about 30 per cent of the microscopic plankton living in the ocean. This means they represent a significant part of the ocean’s smallest living forms. Even though these microbes are extremely small, they perform very important tasks in the ocean. They help control several chemical processes that keep marine environments stable and healthy. Without these microorganisms, many natural reactions in seawater would not happen in the same way. One of their most important roles is helping to change ammonia into other forms of nitrogen. This chemical process is essential in the ocean.
Nitrogen is a key nutrient that many living organisms need to grow and survive. By converting ammonia into other nitrogen compounds, these microbes help move nutrients through seawater. This movement of nutrients allows other microscopic organisms to grow. These small organisms are known as plankton. Plankton are vital in the ocean ecosystem. They form the base of the marine food chain.
Many small animals feed on plankton, and larger animals then feed on those smaller creatures. Fish, marine mammals, and many other species depend on this chain of food. Because of this, microbes like Nitrosopumilus maritimus indirectly support many forms of ocean life. Their chemical activity helps maintain the balance of nutrients in the sea. In this way, tiny microbes play a huge role in keeping marine ecosystems functioning and supporting life throughout the ocean. Once, researchers believed that the warming near the surface mostly protected deep ocean waters. However, new evidence shows that heat from climate change can reach depths of 1,000 meters or more.
This warming may change how microbes use metals like iron, potentially affecting their growth and metabolic processes in the ocean’s ecosystem. Iron is important for their survival and chemical activity. In the study, scientists carried out laboratory experiments using Nitrosopumilus maritimus. They tested the microbes at different temperatures and iron levels. The results were surprising. When temperatures rose and iron became limited, the microbes needed less iron. They also used the available iron more efficiently. This result shows the organism can adjust to warmer waters with fewer nutrients. Researchers also used global ocean computer models. The models showed that these microbes may still play an important role in the ocean’s nitrogen cycle as temperatures continue to rise.
In some regions where iron is limited, their activity could even increase. To further test their findings, the scientists plan to study these microbes in real ocean conditions. Later this year, a team of researchers will travel aboard the research ship Sikuliaq. The expedition will begin in Seattle, move through the Gulf of Alaska, and continue toward the subtropical Pacific, with a stop in Honolulu. About 20 scientists will participate in the journey to examine how temperature and metal availability affect natural populations of these microbes.
