A new study shows that extreme pressure in the deep sea forces nutrients from sinking particles, giving microbes an unexpected food source. Researchers at the University of Southern Denmark led the work, which was published in Science Advances.
The findings indicate that marine snow particles lose up to 50 percent of their carbon and 58 to 63 percent of their nitrogen as they sink to depths of 2 to 6 kilometers. This leakage occurs because hydrostatic pressure squeezes dissolved organic matter from the particles.
First author Peter Stief described the process by saying the pressure acts almost like a giant juicer. Microbes in surrounding seawater can immediately use the released compounds.
Laboratory experiments with diatoms showed bacterial abundance rising 30-fold within two days after the nutrients became available. The study suggests this mechanism operates across multiple diatom species and could affect global carbon storage models.
The research team plans to test the process further during an upcoming expedition to the Arctic Ocean aboard the research vessel Polarstern.