MEPS 417:1-12 (2010)  -  DOI: https://doi.org/10.3354/meps08795

ABSTRACT: Oxygen exchange across the seabed is a key measure for quantifying benthic carbon turnover. However, technical limitations have restricted such measurements to sedimentary areas. Few assessments on hard-bottom substrates exist although such biotopes are frequent along many coastlines. In spring 2009, we used the non-invasive eddy correlation technique to quantify the in situ O₂ exchange rate across 3 typical substrates in West Greenland: (1) in soft sediments, the O₂ exchange in darkness averaged 2.0 mmol m^–2 h^–1. The rate exceeded the O₂ exchange quantified from microprofile measurements by 80%, but was not significantly different from parallel core incubations. (2) Measurements across consolidated sand and stones revealed a high activity with average O₂ exchange similar to that of sedimentary areas. Despite being net heterotrophic, the benthic primary production on average amounted to 27 mmol O₂ m^–2 d^–1, which per unit area is similar to the pelagic gross production of the central fjord. Carbon fixed by benthic diatoms and coralline red algae was efficiently recycled by microbes or grazed by the abundant epifauna. (3) A vertical cliff covered with sea cucumbers also revealed high O₂ consumption rates (1.2 mmol m^–2 h^–1). The O₂ exchange derived from the eddy correlation approach exhibited pronounced short-term variability reflecting the interplay of several dynamic controls, most importantly short-term variations in local hydrodynamics. All together, measurements across hard-bottom substrates revealed active benthic communities that mediate high carbon turnover rates.

KEY WORDS: Benthic photosynthesis · Microsensors · Remineralization · In situ technology · Psolus fabricii · Strongylocentrotus droebachiensis

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Cite this article as: Glud RN, Berg P, Hume A, Batty P, Blicher ME, Lennert K, Rysgaard S (2010) Benthic O2 exchange across hard-bottom substrates quantified by eddy correlation in a sub-Arctic fjord. Mar Ecol Prog Ser 417:1-12. https://doi.org/10.3354/meps08795 Export citation Share:    Facebook - - linkedIn