MEPS 554:35-50 (2016)  -  DOI: https://doi.org/10.3354/meps11780

ABSTRACT: Coastal and shelf systems likely exert major influence on Arctic Ocean functioning, yet key ecosystem processes remain poorly quantified. We employed the aquatic eddy covariance (AEC) oxygen (O₂) flux method to estimate benthic primary production and mineralization in a High Arctic Greenland fjord. Seabed gross primary production (GPP) within the 40 m deep photic zone was highest at 10 m (29 mmol O₂ m^-2 d^-1) and decreased to 5 mmol O₂ m^-2 d^-1 at 40 m, while nighttime community respiration (CR) ranged from 11 to 25 mmol O₂ m^-2 d^-1. CR decreased to ~2.5 mmol O₂ m^-2 d^-1 at 80 m and remained constant with further depth. Fauna activity accounted for ~50% of the CR at depths ≤60 m but was <15% at depths ≥80 m. Benthic GPP and CR were comparable when scaled to the outer fjord area ≤40 m depth (2.7 and 3.1 t C d^-1), and here the seabed was twice as important as the pelagic compartment for primary production. However, when scaled to the entire outer fjord area of which 80% is >40 m, benthic GPP was 26% of the pelagic production. CR was 2-fold higher than GPP over this region (5.7 t C d^-1) and thus net heterotrophic. By scaling AEC-derived Arctic benthic GPP to the entire Arctic Ocean using modelled seabed light data, we estimate an annual Arctic Ocean benthic GPP of 11.5 x 10⁷ t C yr^-1. On average, this value represents 26% of the Arctic Ocean annual net phytoplankton production estimates. This scarcely considered component is thus potentially important for contemporary and future Arctic ecosystem functioning.

KEY WORDS: Benthic primary production · Carbon cycling · Arctic · Aquatic eddy covariance · Benthic macrofauna

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Cite this article as: Attard KM, Hancke K, Sejr MK, Glud RN (2016) Benthic primary production and mineralization in a High Arctic fjord: in situ assessments by aquatic eddy covariance. Mar Ecol Prog Ser 554:35-50. https://doi.org/10.3354/meps11780 Export citation Share:    Facebook - - linkedIn