Fjords are often thought of as beautiful natural features, but new research suggests they could also play a key role in climate regulation.
Sediment data revealed these fjords to be major carbon sinks, the University of Otago reported. Researchers estimated the worldwide fjord system absorbs a staggering 18 million tons of organic carbon annually, which is equivalent to about 11 percent of what is buried by global oceans.
"Therefore, even though they account for only 0.1 [percent] of the surface area of oceans globally, fjords act as hotspots for organic carbon burial," said Candida Savage, of New Zealand's University of Otago.
Fjords are deep estuaries that form at high latitudes in glacial periods, and can be seen in North Western Europe, Greenland, North America, New Zealand, and Antarctica. These new findings suggest fjords are most influential on the atmospheric carbon dioxide levels and Earth's climate during periods when ice sheets are either advancing or retreating.
The Earth is currently in an interglacial period, but during ice sheet retreats (such as the one that occurred 11,700 years ago), fjords are predicted to prevent large concentrations of carbon from breaching the continental shelf, where chemical processes would drive the formation of CO2. If this ice started once again advancing, the organic material would be pushed into shelf, spurring the production of CO2.
The findings were made through an analysis of 573 surface sediment samples and 124 cores taken from fjords across the globe.
"In essence, fjords appear to act as a major temporary storage site for organic carbon in between glacial periods. This finding has important implications for improving our understanding of global carbon cycling and climate change," Savage said.
The findings were published in a recent edition of the journal Nature Geosciences.
