Groundwater plays an important role in transporting carbon and other nutrients to the ocean, but in the Arctic, a large amount of water is still solidified in frozen soil, and it has long been generally believed that the role of groundwater is not obvious. Experiments in NSF Beaufort Lagoon Ecosystem Long-term Ecological Research Base show that a large number of organic substances are dissolved in groundwater below frozen soil, and they eventually enter the Arctic coastal waters with the flow of groundwater. These invisible waters bring a lot of carbon and other nutrients from the land to the North Pole, and their flow is even equivalent to the runoff of rivers nearby in summer. With the melting of permafrost, groundwater is expected to become a growing source of fresh water and nutrition in the Arctic Ocean. It is found that shallow groundwater will absorb new and young organic carbon and nitrogen when it flows under the surface of northern Alaska. When the local groundwater flows to the ocean, it will mix with deep soil layers and melted permafrost, dissolving a lot of soil organic matter and carbon thousands of years ago. According to calculation, the concentration of dissolved organic carbon and nitrogen in frozen ground water near the land-sea junction is two orders of magnitude higher than that in rivers. With the warming of the Arctic, a large amount of organic matter is released from permafrost, and these fluxes are expected to continue to increase.
James mcclelland, a marine scientist at Austin University, pointed out that the water flowing into the Arctic Ocean from rivers has been well studied and explained, but until now, there is little research on groundwater flowing into the Arctic Ocean. In the past, it was thought that little groundwater flowed into the sea from the land in the Arctic, because permafrost or permafrost restricted the water flow below the surface of the permafrost zone. Through this study, it can be explained that groundwater must be considered in different ways, and the transportation of groundwater is becoming more and more important for understanding the carbon and nutrient cycle of the Arctic coastal ecosystem.
Reprint this article, please indicate the source and author: Lanzhou Literature and Information Center of China Academy of Sciences, Dynamic Monitoring Express of Resources and Environmental Sciences, No.07, 2020, compiled by Niu Yibo.