Fjords are narrow, long and deep estuaries.
Researchers have studies the sediment data from worldwide fjord system and they have found that 18 million tones of organic carbon is buried in fjords each year, this estimate is equivalent to 11 percent of marine carbon burial globally each year.
For the research they have analyzed data from 573 surface sediments sample and 124 sediment cores from fjords around the world.
Dr Candida Savage of New Zealand’s University, Otago and her colleagues calculated fjord organic burial per unit area and they found that it is actually twice as large as the ocean average.
Dr Savage said, “Therefore, even though they account for only 0.1% of the surface area of oceans globally, fjords act as hotspots for organic carbon burial.”
Fjords are known for their beauty and are formed at high latitudes during the glacial period as the glaciers incise major valleys near the coast.
Fjords are found in Greenland, North America, New Zealand, Antarctica, and North Western Europe.
Fjords are deep and low oxygen marine system, thus providing a site for carbon rich sediments to accumulate.
Carbon burial is a natural process where carbon sediments are buried, and it is the largest carbon sink on the planet.
This process also influences atmospheric carbon dioxide levels at multi thousand year time scales.
Researchers said that during the times when ice sheets are retreating, fjords can play an important role as a driver of atmospheric carbon dioxide levels.
Earth is currently in Interglacial period, before entering into the Interglacial period Earth was in a period where ice sheets receded; this period is around 11,700 years ago.
During glacial retreat, fjords would trap large volumes of organic carbon flowing out to the continental shelf, where carbon dioxide is produced by some chemical processes.
Once glaciers start advancing again the organic carbon would then be pushed out onto the shelf and co2 production will increase.
Savage said: “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.”