A new study makes it evident that fjords are a major carbon sinker and is playing an essential role in regulating the climate. Fjords refer to long and deep estuaries.
Data from fjord system from all over the world has been studied by researchers which included 573 surface sediments samples and 124 sediment cores from fjords. The result showed that 18 million tones of organic carbon are buried in fjords every year and this figure is equivalent to 11% of the world’s marine carbon burial annually.
The organic burial per unit area of the fjord organic had been calculated by Dr. Candida Savage of New Zealand’s University, Otago and they discovered that is in reality 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.”
Renowned for their beauty, fjords are formed at high latitudes in the duration of glacial periods as the glaciers carve major valleys close to the coast. Mostly found in regions like North America, Greenland, Antarctica, North Western Europe and New Zealand, fjords are deep and low oxygen marine system which is why it provides a site for the accumulation of carbon rich sediments.
Carbon burial is a natural process where carbon sediments are buried and is the largest carbon sink on Earth and this process also have influence on atmospheric carbon dioxide levels at multi-thousand year time scales.
According to researchers, the times when these ice sheets are retreating, fjords can have an essential part for driving the levels of atmospheric carbon dioxide.
At present the earth is in Interglacial period, before entering into it the Earth had been in a period where ice sheets had been receding which had been about 11,700 years back.
In the duration of glacial retreat, fjords would be trapping huge volumes of organic carbons from flowing out to the continental shelf, where carbon dioxide is produced via some kind of chemical process. When the glaciers initiates to advance again, the organic carbon would then be pushed out onto the shelf causing the production of carbon dioxide to elevate.
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.”