Researchers from the University of Alaska Fairbanks have found that methane emissions in Northwestern Alaska are 50 percent higher around beaver ponds than around non-beaver waterbodies. The study was published in Environmental Research Letters.
According to the experts, permafrost thaw in the region caused by flooding could result in the alteration of the Arctic carbon cycle in the long run.
The researchers selected an area (almost 430 square kilometers) of the lower Noatak River basin and studied methane emissions there. The study site is located in the continuous permafrost zone with a mean annual air temperature of about -5°C.
The scientists identified 118 beaver ponds in the area and found 51% greater methane hotspot occurrence ratios around beaver waterbodies to a distance of 25 meters. The experts associate it with the fact that dams turn free-flowing streams into standing water systems, creating anoxic conditions suitable for methanogenesis.
In addition, the researchers say that flooding of lowlands leads to thermokarst processes, permafrost thaw, and the subsequent release of methane. The experts warn that beaver colonization of the tundra could significantly alter the Arctic carbon cycle.