微量金属,海洋微生物 z-bo 2020-12-11 461

　　A new study led by Cornell University shows that trace metals deposited by aerosols such as dust and other particles in the atmosphere have a huge impact on marine biota, affecting biological productivity and changing marine ecosystems.

　　 "In remote oceans, the atmospheric deposition of metals is very important to the biota," said Natalie Mahowald, professor of engineering at the Irving Porter Church and environmental director of the Atkinson Center for Sustainable Development. "During pollution incidents or dust storms, even in these remote places, atmospheric deposition may be the most important source of new metals."

　　 The sources of such aerosol particles include volcanoes, wildfires and desert dust, as well as man-made causes such as burning fossil fuels. After being ejected in the atmosphere and undergoing a chemical reaction, these particles often enter remote ocean areas, where they are deposited through precipitation or dry deposits. Some metals proved to be insoluble and fell to the bottom of the sea, while other metals were absorbed by various biota-"little guys", in Mahowald's words-like phytoplankton and bacteria, which account for 80% of marine life, and As a circulator of oxygen and nutrients in the entire ecosystem.

　　 "If you change the structure of an ecosystem of this scale-this is where all productivity occurs-it will gradually increase and affect the fish and animals we can see more easily," Mahowald said.

　　 Although previous research focused on the key role of iron in the ocean, Mahowald and his team also studied the effects of other metals, including aluminum, manganese, zinc, lead, copper, nickel, cobalt, and cadmium. Many of these metals, such as copper, may be toxic pollutants, but researchers have found that metals sometimes act as nutrients, depending on how, where, and how they are mixed.

　　 "One of the highlights of the paper is heterogeneity," Mahowald said. "Different aerosol sources have different metals, and different biota uses different metals, which will affect phytoplankton. We can’t just talk about the deposition of aerosols in the ocean. We must be very specific about where in the ocean and where it enters Which metals, and the biota that receives them, because the response is to these questions.

　　 According to co-author and postdoctoral colleague Douglas Hamilton, an example of the complexity and subtle interdependence of marine ecosystems is the necessity of iron. Hamilton said: "Even if you have all the main components that people want to grow, such as nitrogen and phosphorus, if you take away the iron deposits in the atmosphere, productivity will basically stop in the vast majority of open oceans." "I think the system can. By other means, other iron enters the system, such as rivers and hydrothermal vents. But the microbial inhabitants of the global oceans are interesting. Without iron deposits in the atmosphere, they are like, "No, we don't do anything anymore. ""