Denitrification and anammox activity in Arctic marine sediments

S Rysgaard, Ronnie Glud, N Risgaard-Petersen, T Dalsgaard

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Abstract

We measured rates of N-2 production through anaerobic NH4+ oxidation with NO2- (anammox) and denitrification in permanently cold (from - 1.7degreesC to 4degreesC) 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(-1) d(-1), O-2 penetration depths ranged from 0.25 to 1.70 cm, and bottom-water NO3- concentrations ranged from 0.3 to 15.3 mumol L-1. Total N-2 production was 34-344 mumol N m(-2) d(-1), of which anammox accounted for 1-92 mumol N m(-1) d(-1) (1-35% of total) and denitrification for 33-265 mumol N m(-2) d(-1). At one of the high-Arctic sites, anammox activity had an optimum temperature (T-opt) of 12degreesC, while that of bacterial denitrification was 24degreesC. According to the classical temperature scheme for metabolic growth, the anammox response was psychrophilic, while denitrification was psychrotrophic. Although T-opt was considerably higher than in situ temperatures, rates of denitrification and anammox were still high at - 1.3degreesC, reaching 17% and 40%, respectively, of those found at T-opt. The activation energies, E-a, of anammox and denitrification were 51.0 and 60.6 kJ mo(-1), respectively, and the corresponding Q(10) values were 2.2 and 2.4. Rates of anammox were linearly correlated with bottom-water NO3- concentrations W = 0.96, p <0.0001, n = 11) at the investigated sites. We suggest that the slow-growing anammox bacteria are favored in sediments with high and stable NO3- conditions. This may be a general pattern in deeper waters at other latitudes as well.
Original languageEnglish
Pages (from-to)1493-1502
Number of pages10
JournalLIMNOL OCEANOGR
Volume49
Issue number5
Publication statusPublished - 2004

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Keywords

  • SULFATE-REDUCING BACTERIA
  • FRESH-WATER
  • TEMPERATURE-DEPENDENCE
  • OXYGEN RESPIRATION
  • ANAEROBIC AMMONIUM OXIDATION
  • SHELF SEDIMENTS
  • Limnology
  • Oceanography
  • MINERALIZATION
  • REDUCTION
  • NITRATE
  • COASTAL SEDIMENT

Cite this

Rysgaard, S., Glud, R., Risgaard-Petersen, N., & Dalsgaard, T. (2004). Denitrification and anammox activity in Arctic marine sediments. LIMNOL OCEANOGR, 49(5), 1493-1502.