Scientists have discovered thousands of new microbes in the hadal zone, the deepest part of the ocean, an area previously unexplored. The study represents a significant step in understanding how life survives in the cold and dark depths of the ocean.
The hadal zone starts at a depth of 6 kilometers (about 4 miles) below the ocean's surface and extends to 11 kilometers (6.8 miles). This depth is roughly the height of 30 Empire State Buildings stacked on top of each other or one and a half times the size of Mount Everest. Life in these dark depths of the ocean is extremely challenging.
A research team from China made 33 dives into the hadal zone, collecting samples from the seafloor and seawater. The analysis revealed 7,564 species of microbes, almost 90% of which were new to science.
The researchers explained that the study addressed a long-standing goal in microbial ecology: "Our research aims to understand how microbial communities, particularly those in extreme conditions, are shaped," they said.
Life in the hadal zone is harsh. The temperatures are near freezing, the water pressure is incredibly high, and food sources are scarce. However, despite these challenges, the diversity of the discovered microbes is surprising.
The researchers identified two main strategies that microbes use to survive. Some microbes have smaller, simpler genomes, allowing them to live efficiently. These microbes have enzymes that provide resistance to stresses in the deep environment. Others have larger genomes, which help them adapt to environmental pressures and survive in a wider range of food sources.
The researchers emphasized the high diversity and heterogeneity of the hadal microbes. This diversity is shaped by environmental conditions and the delicate topography of the hadal zone.
Additionally, microbes often cluster together in suitable areas in the deep ocean, forming mixtures of different microbes with minimal overlap.
As the depth increases, it was observed that microbes collaborate to survive. These microorganisms share nutrients and protect their communities by creating protective biofilms, helping them endure the extreme conditions.
The research team has made their findings available online for scientific review. The "Mariana Trench Environment and Ecology Research (MEER)" project has opened new opportunities to understand how life continues in extreme environments.
