Benthic primary production and mineralization in a High Arctic fjord: in situ assessments by aquatic eddy covariance

Abstract

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 × 10 7 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.

Sea ice and primary production proxies in surface sediments from a High Arctic Greenland fjord: Spatial distribution and implications for palaeoenvironmental studies

“…However, the biomass of ice algae and their productivity in Young Sound appears to be relatively low (Rysgaard et al 2001). Benthic microalgae are also found in abundance on the seafloor where they contribute significantly to the total production of the outer part of Young Sound, especially at shallow depths (Attard et al 2016). …”

Oxygen fluxes beneath Arctic land-fast ice and pack ice: towards estimates of ice productivity

“…Here, the method constitutes a strong tool for quantifying primary productivity, respiration, and the net ecosystem metabolism rates non-invasively across complex and hard benthic surfaces that characterize much of the Arctic coastal zone Attard et al 2014Attard et al , 2016. Sea-ice represents a challenge for metabolism studies similar to hard benthic surfaces, in that the underside of the ice pack is a solid, often uneven surface with a patchy distribution of biotic communities Katlein et al 2014;Lange et al 2016).…”

The transformation and fate of sub‐Arctic microphytobenthos carbon revealed through 13 C‐labeling

“…Recent evidence suggests that benthic primary production in Arctic ecosystems might be more important than previously anticipated (Glud et al ; Attard et al ). For instance, on average, MPB in the Arctic appear to contribute more to shallow water (>30 m) productivity than phytoplankton (Glud et al ; Attard et al ), and the productivity and biomass of MPB in the Arctic scale with that of MPB in temperate regions (Glud et al ; Woelfel et al ).…”