Mitigating the effects of climate change are generally focused around reducing carbon emissions in the atmosphere. Researchers, however, have found that fjords can contribute greatly to the effort through carbon sequestration.

Carved by receding glaciers, fjords are found from Antarctica to Alaska. A study published in the journal Nature Geosciences showed that the inlets are capable of capturing and storing carbon better compared to other marine systems out in the open water. Carbon sequestration is not yet fully understood but based on what they can do, it looks like fjords have to be taken into consideration when making decisions regarding land use and predicting climate events.

Fjords only represent a small fraction of marine systems but they have been recorded as having the capacity to store 11 percent of carbon buried in oceans, which translates to around 18 million metric tons every year. Keeping carbon locked up prevents it from turning into carbon dioxide, one of the foremost causes of warming in the atmosphere.

Its shape contributes to a fjord's efficiency at storing carbon, a deep and narrow V shape that lets carbon sink down into zones with low oxygen levels where it won't be eaten by aerobic bacteria, which results into carbon re-entering the atmosphere in the form of a greenhouse gas.

This isn't the first time that researchers have discovered fjords as excellent at carbon storage but not a lot of attention was given to the coastal environments because they represent just a tenth of a percent of the oceans in the world.

"Most of the focus has been on the big river deltas, because they drain so much more surface area in their large watersheds," said Thomas Bianchi from the University of Florida and one of the authors for the study.

Researchers took surface and core sediment samples from New Zealand's fjords, comparing them to data previously derived from Antarctica, Chile, Alaska, Svalbard, Greenland, Scotland, Sweden, Norway, British Columbia, and Arctic and sub-Arctic Canada.

Results showed that fjords have efficiency levels five times higher than continental shelves when it comes to carbon sequestration. Averaged according to area, fjords also had carbon sequestration capacities double than that of what oceans are capable of overall.

Researchers hope the results of the study will highlight the importance of fjords in conservation efforts, noting the important service the inlets are performing for the world.

Richard Smith, Valier Galy, Candida Savage and Mead Allison also contributed to the study.