Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord ...

• Main Authors: Sejr, Mikael et al., Bruhn, Annette, Dalsgaard, Tage, Juul-Pedersen, Thomas, Stedmon, Colin, Blicher, Martin, Meire, Lorenz, Mankoff, Kenneth, Thyrring, Jakob
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Zenodo 2022
• Subjects: Greenland; glacier; Ice Sheet
• Online Access: https://dx.doi.org/10.5281/zenodo.7501034; https://zenodo.org/record/7501034

Global warming accelerates melting of glaciers and increases the supply of meltwater and associated inorganic particles, nutrients, and organic matter to adjacent coastal seas, but the ecosystem impact is poorly resolved and quantified. When meltwater is delivered by glacial rivers, the potential impact could be a reduction in light and nutrient availability for primary producers while supplying allochthonous carbon for heterotrophic processes, thereby tipping the net community metabolism toward heterotrophy. To test this hypothesis, we determined physical and biogeochemical parameters along a 110-km fjord transect in NE Greenland fjord, impacted by glacial meltwater from the Greenland Ice Sheet. The meltwater is delivered from glacier-fed river outlets in the inner parts of the fjord, creating a gradient in salinity and turbidity. The planktonic primary production was low, 20–45 mg C m−2 d−1, in the more turbid inner half of the fjord, increasing 10-fold to around 350 mg C m−2 d−1 in the shelf waters ...