Denitrification in coastal bay sediment: regional and seasonal variation in Aarhus Bight, Denmark

Mh, Jensen; Andersen, TK; Sørensen, Jan

doi:10.3354/meps048155

Cited by 49 publications

(38 citation statements)

References 26 publications

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“…The remaining N loss in OX-cores could b e explained by a coupled nitrificationdenitrification rate of 5.1 mm01 m-2 d-'. In comparison, Jensen et al (1988) found at the same locality that the in situ denitrification rate did not exceed 1 mm01 m-' d-l, measured over a year. However, S. Seitzinger (pers.…”

Section: Discussionmentioning

confidence: 94%

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Anaerobic mineralization of marine sediment organic matter: Rates and the role of anaerobic processes in the oceanic carbon economy

Henrichs¹,

Reeburgh²

1987

Geomicrobiology Journal

492

161

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Fluxes of total CO2, 02, NO3-+NO2-, NH,', DON (dissolved organic nitrogen) and HSwere measured across the interface of a coastal bay sediment for 43 d. The seawater overlying the defaunated sediment cores was changed continuously. Two treatments were employed: oxygenated overlying water (OX-cores) and anoxic water (AN-cores). Fluxes were measured before and after addition of an organic substrate, and loss of POM (particulate organic matter) was measured at the end of the experiment. Loss of POC (particulate organic carbon) from the sediment was the same under aerobic and anaerobic conditions. However, the highest efflux of CO2 was measured in the OX-cores, and the highest efflux of DOC occurred in the AN-cores before and after addition of fresh substrate. Similarly, loss of PON (particulate organic nitrogen) from the sediment was the same in the 2 treatments, but the highest fluxes of NH,' and DON were measured In the AN-cores. Our conclusion is that degradation of POM is the same under both aerobic and anaerobic condltlons, but that mineralization of organic molecules is less effective under anaerobic condlhons. Before substrate addit~on there was an influx of NO3-in both OX-and AN-cores, and the estimated nitrification rate in the OX-cores was 1 to 2 mm01 m-' d-l The estimated denitrification rate contributed 3 to 6 '10 to total carbon respiration. After addition of the substrate, fluxes of all constituents increased. The estimated denitrification rate constituted < 3 '10 of total respiration. There was a large efflux of HS-in AN-cores During the experimental period, the losses of original POC and PON were calculated to be 2.6 and 4.0 %, respectively. Relative to the initial values, the pore water constituents increased with incubation, and the integrated AN/OX ratios for N H d f , DON and total CO2 were 1.2, 1.5 and 1.6, respectively, after 43 d.

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Section: Discussionmentioning

confidence: 94%

“…comm.) has shown by another procedure that the acetylene method used by Jensen et al (1988) might considerably underestimate the rate. Moreover, Blackburn & Henriksen (1983) and Seitzinger et al (1984) showed that 7 and 3 5 % , respectively, of NH4+ production is nitrified and subsequently denitrified in similar coastal sediments.…”

Section: Discussionmentioning

confidence: 99%

Anaerobic mineralization of marine sediment organic matter: Rates and the role of anaerobic processes in the oceanic carbon economy

Henrichs¹,

Reeburgh²

1987

Geomicrobiology Journal

492

161

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“…The investigation was carried out between September 1987 and August 1988 at a 15 m deep site in Aarhus Bight (Stn 16 of Jensen et al 1988Jensen et al , 1990 in the southwestern Kattegat. Sampling was most intensive during spring, when cores were collected 2 to 4 times per month.…”

Section: Methodsmentioning

confidence: 99%

Intracellular NH4 and NO5 pools associated with deposited phytoplankton in a marine sediment (Aarhus Bight, Denmark)

Lomstein¹,

Jensen²,

Sørensen³

1990

Mar. Ecol. Prog. Ser.

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Concentration profiles of NH., and NO? in pore water and particulate matter were determined at high spatial resolution (mm bcale) in surface sediment from a coastal bay area (Aarhus Bight, Denmark) at 15 m depth during an annual cycle. Pore water pools of NH: and NO; were always considerably lower than particulate pools in the surface sediment. Particulate NH: and NO; were apparently intracellular pools in deposited microalgae and were extracted after freezing sedlment samples in liquid NZ (-196 "C). Pore water NH: and most of the adsorbed (KCI-extractable) NH: were also extracted by the freezing technique, and an estimate of the intracellular NH: pool was obtained by difference. In the absence of an adsorbed NOS pool, intracellular NO? was determined by subtraction of the pore water pool from the liquid NZ-extractable pool. Highest concentrations of intracellular NH: and NO; were always observed in the upper 2 mm of sediment, declining sharply with depth. A distinct seasonal maximum for both pools, ca 200 nmol cm-3 at 0 to 2 mm depth, appeared after sedimentation of a phytoplankton bloom in early spring, and should be compared to a minimum of only 25 nmol or less in fall and winter. The freeze-extraction technique is proposed for a reliable estimate of intracellular NH: and NO; pools in surface sediments r~c h In microalgae, and may thus be used as an indicator of sedimentation of phytoplankton blooms. The signiflcance of intracellular pools for sediment nitrogen cycling is discussed.

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“…Addition of fresh algal organic carbon to the sediment-water interface created a strong flux of NO2-+ NO3-into the sediments from the water, perhaps due to the stimulation of denitrification, the reduction of NO3-to N1 Ronner (1985) estimated that 55% of nitrogen loading to the Baltic is denitrified on an annual basis, and increases in denitrification in response to elevated organic loadings have been reported for similar cold temperate sediments (Henriksen et al 1981, Jensen et al 1988, Hansen & Blackburn 1991, Caffrey et al 1993. Also, a significant increase in denitnfication has been observed in sediments local to the present study sight as a result of the sedimenting annual spring bloom ( 'Could not b e calculated because all NO3-was depleted from both the water and from the sediment porewaters ments in the l x cores but a significant flux into the sediment in the 3 x cores.…”

Section: Nitrogen Remineralization Processesmentioning

confidence: 99%

Biogeochemistry of N, P and Si in Baltic Sea sediments:response to a simulated deposition of a spring diatom bloom

Dj¹,

Johnstone²

1995

Mar. Ecol. Prog. Ser.

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Experimental studies of intact cores from the Baltic Sea were conducted to determine the response of sediment nutrient recycling processes to varied inputs of organic matter. A 2 mo enrichment experiment was carried out in the laboratory on sediment cores held at 4°C using a flow-through system where overlying waters were continuously replaced at a rate of 1 d.' The experiments were designed to simulate the deposition of organic matter that occurs during a typical spring diatom bloom ( l x ) and under enriched conditions with eutrophicatlon at approximately 3 times (3x) a normal spring bloom utilizing added organic matter from a natural phytoplankton assemblage collected in a eutrophic coastal fjord during the spring diatom bloom. Low and constant sediment-water fluxes were observed throughout the duration of the experiment in control cores with no added organic matter. In all cases an immediate response was noted when a single pulsed addition of algal material was added to the sediment surface. Sediment-water fluxes of ammonium (NHdt), and dissolved inorganic phosphate (DIP) increased significantly (ANOVA, p < 0.01). For nitrite + nitrate (NO; + NO3-) and dissolved silicate (DSi) sediment-water fluxes, differences were initially observed; however, only the NO2-+ NO3-fluxes were significantly different over time (ANOVA, p < 0.01). Fluxes of NOz-+ NO3-were into the sediment for 3 to 10 d after addition of organic material, followed by small fluxes out of the sediment. The addition of algal material proportionate to a normal spring bloom ( l x ) had only a minor effect on porewater nutrient concentrations, whereas the 3x treatment substantially modified both the short-and long-term response of sediments. A greater proportion of anaerobic decomposition products, e.g. NH,' and DIP, were observed with an expansion of more reducing conditions resulting from the addition of organic matter. The percentage of Si remineralized decreased as the flux of n~aterial to the sediment increased. Deposition rates similar to a typical spring bloom did not have long-term effects on the nutrient recycling processes; however, increases in the present level of deposition (as simulated in this study), which are forecasted with further eutrophication in the Baltic Sea, may have a significant impact on nutrient biogeochernical cycles.

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Denitrification in coastal bay sediment: regional and seasonal variation in Aarhus Bight, Denmark

Cited by 49 publications

References 26 publications

Anaerobic mineralization of marine sediment organic matter: Rates and the role of anaerobic processes in the oceanic carbon economy

Anaerobic mineralization of marine sediment organic matter: Rates and the role of anaerobic processes in the oceanic carbon economy

Intracellular NH4 and NO5 pools associated with deposited phytoplankton in a marine sediment (Aarhus Bight, Denmark)

Biogeochemistry of N, P and Si in Baltic Sea sediments:response to a simulated deposition of a spring diatom bloom

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