Summary We investigated anammox, denitrification and dissimilatory reduction of nitrite to ammonium ( DNRA ) activity in the E astern T ropical S outh P acific oxygen minimum zone ( OMZ ) off northern C hile, at high‐depth resolution through the oxycline into the anoxic OMZ core. This was accompanied by high‐resolution nutrient and oxygen profiles to link changes in nitrogen transformation rates to physicochemical characterist...

We measured net planktonic community production (NCP), community respiration (CR), and gross primary production (GPP) in September, February, and May in a subarctic Greenland fjord influenced by glacial meltwater and terrestrial runoff. Potential controls of pelagic carbon cycling, including the role of terrestrial carbon, were investigated by relating surface‐water partial pressure of CO 2 (P CO2 ), NCP, GPP, and CR to physic...

We quantified the removal of fixed nitrogen as N 2 production by anammox and N 2 and N 2 O production by denitrification over a distance of 1900 km along the coasts of Chile and Peru, using short‐term incubations with 15 N‐labeled substrates. The eastern South Pacific contains an oxygen minimum zone (OMZ) characterized by an anoxic, nitrate‐ and nitrite‐rich layer of ∼ 200‐m thickness below 30–90 m of oxic water. Anammox and d...

In this article, we examine the air‐sea exchange of exchangeable organic carbon (OC) as well as the internal pools and sources within a subarctic fjord. Air‐water fluxes of OC ranged from an uptake of 22 ± 10 mmol C m −2 d −1 in winter to a release of 2 ± 8 mmol C m −2 d −1 in the fall, sizable compared to that of CO 2 (average uptake of 136 mmol C m −2 d −1 for the fall and 2.6 ± 0.84 mmol C m −2 d −1 in the winter). The wate...

Summary Laboratory and field studies have indicated that anaerobic ammonium oxidation (anammox) is an important process in the marine nitrogen cycle. In this study 11 additional anoxic marine sediment and water column samples were studied to substantiate this claim. In a combined approach using the molecular methods, polymerase chain reaction (PCR), qualitative and quantitative fluorescence in situ hybridization (FISH), as wel...

We measured rates of N2 production through anaerobic NH 4 + oxidation with NO 2 −(anammox) and denitrification in permanently cold (from −1.7°C to 4°C) sediments off the east and west coasts of Greenland. The investigated sites (36– to 100–m water depth) covered sediments in which carbon contents ranged from 0.3 to 3.2 dry weight %, O 2 uptake rates ranged from 3.4 to 8.3 mmol m −2 d −1 , O 2 penetration depths ranged from 0.2...

Annual rates of sediment denitrification and sediment—water fluxes of oxygen and nutrients were quantified at two shallow locations, Virksund and Ulbjerg, in the Limfjorden, Denmark. The sediment was sandy and colonized mainly by bivalves with a wet weight of 2,508 g m −2 at Virksund and 572 g m −2 at Ulbjerg. A benthic microalgal community was present throughout the year, and for 1–2 months in the summer, floating macroalgae...