Dr Candida Savage, of the Otago marine science department, was ''delighted'' the international study had just been published in a leading journal, Nature Geoscience.
The Otago research was part of a larger international project that started with a research cruise in Fiordland in 2007 and continued with a ''more targeted'' research trip in 2010 with American colleagues, she said in an interview.
After studying sediment data from worldwide fiord systems, the researchers, including Dr Savage, estimated that about 18 million tonnes of organic carbon was buried in fiords each year, equivalent to 11% of annual marine carbon burial globally.
Dr Savage and colleagues calculated that per unit area, fiord organic carbon burial rates were twice as large as the ocean average.
And, therefore, although accounting for only 0.1% of the surface area of oceans globally, ''fiords act as hot spots for organic carbon burial'', she said.
This was the first worldwide study that demonstrated fiords were important carbon burial sites.
Several New Zealand fiords were included in the study, including Doubtful Sound, Dusky Sound and Preservation Inlet.
''We are very excited to get this research published and plan to conduct further research on fiords in the future.''
The long-term storage of carbon in sediments played an important role in controlling atmospheric carbon dioxide concentrations and was therefore a key process in climate change.
The New Zealand fiords studied were in a geologically active region with steep slopes and very high rainfall.
Earthquakes contributed to landslips, which moved many trees into the fiords, where this organic carbon was not significantly changed before it was buried in the sediments.
Fiords were found in northwest Europe, Greenland, North America, New Zealand and the Antarctic.
They were long, deep and narrow estuaries formed at high latitudes during glacial periods as advancing glaciers cut out major valleys near the coast.
Carbon burial provided the largest carbon sink on the planet and influenced atmospheric carbon dioxide levels.
The research was part of a larger study into organic carbon cycling in fiords and involved international collaborators and several PhD students at Otago and in the United States, she said.
