Environmental overview of Eckernf�rde Bay, northern Germany

Orsi, Thomas H.; Werner, Friedrich; Milkert, Doris; Anderson, A.; Bryant, William R.

doi:10.1007/bf01204501

Cited by 38 publications

(28 citation statements)

References 11 publications

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“…Bioturbating and bioirrigating organisms can transport O 2 much deeper into sediments than molecular diffusion (Orsi et al, 1996;. In coastal waters, the bioturbation and bioirrigation activity of ghost shrimps was found to reduce N 2 fixation when sediments were highly colonized by these animals .…”

Section: Oxygenmentioning

confidence: 99%

Nitrogen fixation in sediments along a depth transect through the Peruvian oxygen minimum zone

et al. 2016

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Abstract. The potential coupling of nitrogen (N 2 ) fixation and sulfate reduction (SR) was explored in sediments of the Peruvian oxygen minimum zone (OMZ). Sediment samples were retrieved by a multiple corer at six stations along a depth transect (70-1025 m water depth) at 12 • S, covering anoxic and hypoxic bottom water conditions. Benthic N 2 fixation, determined by the acetylene reduction assay, was detected at all sites, with highest rates between 70 and 253 m and lower rates at greater depth. SR rates decreased with increasing water depth. N 2 fixation and SR overlapped in sediments, suggesting a potential coupling of both processes. However, a weak positive correlation of their activity distribution was detected by principle component analysis. A potential link between N 2 fixation and sulfate-reducing bacteria was indicated by the molecular analysis of nifH genes. Detected nifH sequences clustered with the sulfate-reducing bacteria Desulfonema limicola at the 253 m station. However, nifH sequences of other stations clustered with uncultured organisms, Gammaproteobacteria, and Firmicutes (Clostridia) rather than with known sulfate reducers. The principle component analysis revealed that benthic N 2 fixation in the Peruvian OMZ is controlled by organic matter (positive) and free sulfide (negative). No correlation was found between N 2 fixation and ammonium concentrations (even at levels > 2022 µM). N 2 fixation rates in the Peruvian OMZ sediments were in the same range as those measured in other organic-rich sediments.

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Section: Oxygenmentioning

confidence: 99%

Nitrogen fixation in sediments along a depth transect through the Peruvian oxygen minimum zone

et al. 2016

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“…Sediments at BE are generally classified as soft, fine-grained muds (< 40 µm) with a carbon content of 3 to 5 wt % (Balzer et al, 1986). The bulk of organic matter in Eckernförde Bay sediments originates from marine plankton and macroalgal sources (Orsi et al, 1996), and its degradation leads to the production of free methane gas (Wever and Fiedler, 1995;Abegg and Anderson, 1997;Wever et al, 1998). The oxygen penetration depth is limited to the upper few millimeters when bottom waters are oxic (Preisler et al, 2007).…”

Section: Study Sitementioning

confidence: 99%

Microbial methanogenesis in the sulfate-reducing zone of sediments in the Eckernförde Bay, SW Baltic Sea

et al. 2018

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Abstract. Benthic microbial methanogenesis is a known source of methane in marine systems. In most sediments, the majority of methanogenesis is located below the sulfatereducing zone, as sulfate reducers outcompete methanogens for the major substrates hydrogen and acetate. The coexistence of methanogenesis and sulfate reduction has been shown before and is possible through the usage of noncompetitive substrates by methanogens such as methanol or methylated amines. However, knowledge about the magnitude, seasonality, and environmental controls of this noncompetitive methane production is sparse. In the present study, the presence of methanogenesis within the sulfate reduction zone (SRZ methanogenesis) was investigated in sediments (0-30 cm below seafloor, cm b.s.f.) of the seasonally hypoxic Eckernförde

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“…Pockmark sites were rarely explored because it is very difficult to obtain samples or recordings even though the highest flow rates are expected there. The strong and persistent fluid discharge supersaturates the pore space of the sediment (Orsi et al 1996;Nittrouer et al 1998). The seabed is better described by a fluid/sediment suspension with no clearly defined sediment-water interface.…”

Section: Discussionmentioning

confidence: 99%

Groundwater discharges in the Baltic Sea: survey and quantification using a schlieren technique application

2006

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Groundwater seeps are known to occur in Eckernfö rde Bay, Baltic Sea. Their discharge rate and dispersion were investigated with a new schlieren technique application, which is able to visualize heterogeneous water parcels with density anomalies down to Dr t ¼ 0.049 on the scale of millimeters. With the use of an inverted funnel, discharged fluids can be captured and the outflow velocity can be determined. Overall, 46 stations could be categorized by three different cases: active vent sites, seep-influenced sites, and non-seep sites. New seep locations were discovered, even at shallow near-shore sites, lacking prominent sediment depression, which indicate submarine springs. The detection of numerous seeps was possible and the groundwater-influenced area was defined to be approximately 6.3 km 2 . Flow rates of between 0.05 and 0.71 l m )2 min )1 were measured. A single focused fluid plume, which was not disturbed by the funnel was recorded and revealed a flux of 59.6 ± 20 ml cm )2 min )1 and it was calculated that this single focused plume would be strong enough to produce a flow rate through the funnel of 1.32 ± 0.44 l m )2 min )1 . The effect of different seep-meter funnel sizes is discussed.

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Environmental overview of Eckernf�rde Bay, northern Germany

Cited by 38 publications

References 11 publications

Nitrogen fixation in sediments along a depth transect through the Peruvian oxygen minimum zone

Nitrogen fixation in sediments along a depth transect through the Peruvian oxygen minimum zone

Microbial methanogenesis in the sulfate-reducing zone of sediments in the Eckernförde Bay, SW Baltic Sea

Groundwater discharges in the Baltic Sea: survey and quantification using a schlieren technique application

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