Denitrification by sulphur oxidizing Beggiatoa spp. mats on freshwater sediments

Sweerts, Jean-Pierre R. A.; Beer, Dirk de; Nielsen, Lars Peter; Verdouw, H.; Heuvel, J.C. van den; Cohen, Yehuda; Cappenberg, T.E.

doi:10.1038/344762a0

Cited by 104 publications

(79 citation statements)

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“…The genetic potential for such a metabolism is also indicated in Beggiatoa (Mussmann et al, 2007 DNRA is well documented in both Beggiatoa and Thioploca (Otte et al, 1999;Sayama, 2001;Sayama et al, 2005;Preisler et al, 2007). In addition to this, it seems that at least some marine and freshwater Beggiatoa have the capacity to denitrify (Sweerts et al, 1990;Mussmann et al, 2007). A study of nitrogen metabolism in Thioploca left the question about denitrification in this genus open (Otte et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Physiology and behaviour of marine Thioploca

et al. 2009

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Among prokaryotes, the large vacuolated marine sulphur bacteria are unique in their ability to store, transport and metabolize significant quantities of sulphur, nitrogen, phosphorus and carbon compounds. In this study, unresolved questions of metabolism, storage management and behaviour were addressed in laboratory experiments with Thioploca species collected on the continental shelf off Chile. The Thioploca cells had an aerobic metabolism with a potential oxygen uptake rate of 1760 lmol O 2 per dm 3 biovolume per h, equivalent to 4.4 nmol O 2 per min per mg protein. When high ambient sulphide concentrations (B200 lM) were present, a sulphide uptake of 6220 ± 2230 lmol H 2 S per dm 3 per h, (mean ± s.e.m., n ¼ 4) was measured. This sulphide uptake rate was six times higher than the oxidation rate of elemental sulphur by oxygen or nitrate, thus indicating a rapid sulphur accumulation by Thioploca. Thioploca reduce nitrate to ammonium and we found that dinitrogen was not produced, neither through denitrification nor through anammox activity. Unexpectedly, polyphosphate storage was not detectable by microautoradiography in physiological assays or by staining and microscopy. Carbon dioxide fixation increased when nitrate and nitrite were externally available and when organic carbon was added to incubations. Sulphide addition did not increase carbon dioxide fixation, indicating that Thioploca use excess of sulphide to rapidly accumulate sulphur rather than to accelerate growth. This is interpreted as an adaptation to infrequent high sulphate reduction rates in the seabed. The physiology and behaviour of Thioploca are summarized and the adaptations to an environment, dominated by infrequent oxygen availability and periods of high sulphide abundance, are discussed.

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Section: Introductionmentioning

confidence: 99%

Physiology and behaviour of marine Thioploca

et al. 2009

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“…Studies of freshwater and brackish-water Beggiatoa spp. showed that, by contrast, these bacteria could be denitrifiers, reducing NO 3 Ϫ to elemental N 2 (Sweerts et al 1990). Measurements on undisturbed mats of Beggiatoa spp.…”

Section: Effect Of Phytoplankton Blooms On Benthic Nh Produc-mentioning

confidence: 99%

“…It has recently been suggested that marine mats of these bacteria might produce NH 4 ϩ through dissimilatory NO 3 Ϫ reduction to ammonium (DNRA) like Thioploca (Farías 1998;Otte et al 1999). Sweerts et al (1990) gave evidence that freshwater Beggiatoa spp. were able to reduce NO 3 Ϫ to nitrogen gas at up to 2.5 mmol m Ϫ2 d Ϫ1 .…”

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confidence: 99%

Massive developments of microbial mats following phytoplankton blooms in a naturally eutrophic bay: Implications for nitrogen cycling

Graco

Farı́as

Molina

et al. 2001

Limnology & Oceanography

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Benthic nitrogen processes have received substantial attention because the release of nutrients from sediments can contribute to the requirements of pelagic primary production; their study can also give an estimation of the importance of the sediment as a source or a sink of nutrients. Concepción Bay is located in central Chile and is the largest (167.4 km 2 ) and most enclosed embayment on the Chilean coastline. The bay is characterized by a strong hydrographic variability produced by the spring/summer seasonal upwelling of Equatorial subsurface waters (ESSW), rich in nutrients (ϳ25 M NO 3 Ϫ ) and poor in oxygen (Ͻ44.6 M). The area was studied in order to understand the consequences of phytodetrital deposition and oxygen deficiency on the environment and benthic communities. The study was carried out by sampling at a single station (28-m depth) in the inner part of the bay during winter (June 1998) and spring/summertime (November 1998 and January and March 1999). It was focused on measurements of benthic nitrogen fluxes, sulfate reduction, and denitrification rates before and after a phytoplankton bloom. Additionally, samples from the flocculent layer and from a semipurified bacterial mat were incubated under controlled oxygen conditions to determine NH 4 ϩ production. NH 4 ϩ exchange showed a clear seasonal pattern, with influxes during the winter (Ϫ7.6 Ϯ 4.9 mmol m Ϫ2 d Ϫ1) and high effluxes during the summer (36.6 and 20.8 mmol m Ϫ2 d Ϫ1 ) when the accumulation of fresh organic matter (evidenced as chlorophyll a) produced a flocculent layer over the sediments. Besides natural hypoxia of the bottom water associated with ESSW, the large input of organic matter resulted in anoxia within the sediment, as a consequence of respiration processes, and an enhancement in sulfate reduction rates (up to 200 mmol m Ϫ2 d Ϫ1 ). The flocculent layer then provided a favorable environment for the extensive development of Beggiatoa spp. mats. Overall, during the sampling period, NO 3 Ϫ was consumed at an average rate of 1.33 mmol m Ϫ2 d Ϫ1. In the summer, denitrification appeared to be partially inhibited by the very negative redox conditions and could explain only 24% of the NO 3 Ϫ uptake by the sediment. The balance may be due to NO 3 Ϫ incorporation into Beggiatoa spp. Short incubations with these bacteria suggest that they are able to produce NH 4 ϩ by dissimilatory NO reduction, taking advantage of their ability to store NO 3 Ϫ , though its Ϫ 3 uptake was not observed in these experiments. The NH 4 ϩ flux obtained using Beggiatoa spp. mat cultures was 5 mmol m Ϫ2 d Ϫ1 , which accounts for 17% of the total NH 4 ϩ efflux during the summer period (January and March). The ecological implications of a large input of organic matter, evidenced by the presence of a flocculent benthic layer and Beggiatoa spp., are discussed in relation to their contribution, during the upwelling season, toward the long-term eutrophication of Concepción Bay.High rates of primary production in the world oceans take place in coastal areas. Th...

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“…Oxygen microsensors are used widely in marine science to monitor the rate of oxygen production and consumption in sediments (Revsbech, 1989;Sweerts et al, 1990;Wetzel et al, 1995). They have been increasingly used in ecotoxicology to estimate respiratory activity by measuring dissolved oxygen in culture media Hynes et al, 2006;O'Mahony and Papkovsky, 2006).…”

Section: Introductionmentioning

confidence: 99%

Suitability of Contact-Free Oxygen Optical Microsensors for Measuring Respiration and Photosynthesis in Green Algae

Zhang

Filser

2017

Front. Environ. Sci.

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Oxygen optical microsensors are a sensitive method to monitor oxygen production and consumption in soils, sediments, and aquatic systems. They have been used widely to analyze the activity and metabolism of aerobic organisms, also in ecotoxicological tests. We aimed to assess the suitability of a contact-free device to measure cell respiration and photosynthesis for future applications in ecotoxicological tests. One of the most important advantages of this modified method is that respiration and photosynthesis of test organisms which are contaminated with test chemicals can be measured without contact between sensor and test medium. Therefore, it avoids sensor contamination. In an array of calibration tests with Chlorella vulgaris in green algae medium, algal cell activity was well-correlated with cell counts. Results clearly showed that, compared to O 2 evolution rate, O 2 assimilation rate measured by oxygen optical microsensors in a contact-free manner could better predict the algae cell counts. In a second test series we measured O 2 assimilation rate in soil from a field experiment inoculated with different communities of terrestrial algae. No significant difference was observed when comparing measurements of their activity with microsensors to results obtained with the Warburg respiratory manometer. However, optical microsensors are much faster and more easily applied than the traditional manometer. Therefore, the developed method appears promising for application in ecotoxicological tests in the future.

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Denitrification by sulphur oxidizing Beggiatoa spp. mats on freshwater sediments

Cited by 104 publications

References 14 publications

Physiology and behaviour of marine Thioploca

Physiology and behaviour of marine Thioploca

Massive developments of microbial mats following phytoplankton blooms in a naturally eutrophic bay: Implications for nitrogen cycling

Suitability of Contact-Free Oxygen Optical Microsensors for Measuring Respiration and Photosynthesis in Green Algae

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