Biogeochemical cycling in fjords

Fjords play an important, yet rapidly changing and underexplored role in regional and global carbon and nutrient cycles. They are amongst the most productive ecosystems and have been identified as hotspots of organic carbon (OC) burial. Their sediments store an equivalent of ~11% of the annual organic carbon burial flux in marine sediments while accounting for merely ~0.12% of the ocean’s surface. In addition, most fjords are under the direct influence of glacial meltwaters that supply large amounts of bioavailable carbon and iron to downstream ecosystems. Fjords are thus important routes through which glacially derived carbon and nutrients reach the global coastal ocean. Over the past decades, these glacier meltwater fluxes have significantly increased due to the global warming-driven recession of glaciers and ice shields worldwide. It is expected that this sharp increase will further accelerate in response to projected climate change.

We use both reaction-transport models, as well as laboratory experiments to increase our understanding of the mechanisms that enhance C burial in these environments and evaluate the role of Fjords as modulators of glacier carbon and nutrient fluxes.

Relevant project(s): PISCES, CuIRASS, DE-HEAT, CANOE

Key publications:

  • Bianchi T.S., Arndt S., Austin W.E.N., Benn D.I., Bertrand S., Cui X., Faust J.C., Koziorowska-Makuch K., Moy C.M., Savage C., Smeaton C., Smith R.W. and Syvitskil J. (2020) Fjords as Aquatic Critical Zones (ACZs). Earth-Science Reviews, vol. 203, doi: 10.1016/j.earscirev.2020.103145.