Bodden waters (southern Baltic Sea) as a source of methane and nitrous oxide
Dahlke, S.; Wolff, C.; Meyer-Reil, L.-A.; Bange, H.W.; Ramesh, R.; Rapsomanikis, S.; Andreae, M.O. (2000). Bodden waters (southern Baltic Sea) as a source of methane and nitrous oxide, in: Flemming, B.W. et al. (Ed.) Muddy coast dynamics and resource management. Proceedings in Marine Science, 2: pp. 137-148
In: Flemming, B.W.; Delafontaine, M.T.; Liebezeit, G. (Ed.) (2000). Muddy coast dynamics and resource management. Proceedings in Marine Science, 2. Elsevier: Amsterdam. ISBN 0-444-50464-8. 294 pp., more
In: Proceedings in Marine Science. Elsevier: New York. ISSN 1568-2692; e-ISSN 2352-2860, more
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| Authors | | Top |
- Dahlke, S.
- Wolff, C.
- Meyer-Reil, L.-A.
- Bange, H.W.
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- Ramesh, R.
- Rapsomanikis, S.
- Andreae, M.O.
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| Abstract |
A first assessment of N2O and CH4 emissions from Bodden waters (southern Baltic Sea) was carried out with the aim of investigating the seasonal and spatial variability the emissions as well as characterizing the corresponding biological processes (i.e. denitrification, nitrification, and methanogenesis) along pronounced gradients in trophic status and salinity. Saturation values of CH4 varied from 102 to 16,300%. Supply of organic carbon to sediments, temperature, and input of riverine CH4 can be considered as import controls on methane concentration. The influence of salinity seems to be insignicant in this respect. On average, 86% of sedimentary methane is oxidized within sediment. In contrast, methane oxidation is restricted to the water column when stagnation of water bodies occurs. In addition to the seasonal pattern, a diurnal rhythm of methane concentrations was detected. The N2O saturation values of the Bodden waters were low (90 to 309%), and showed a significant correlation with nitrate concentrations (r = 0.83). The Peene River was identified as a strong source for allochthonous N2O. From the present data hypothesized that, in the inner Bodden waters, high riverine loads of nitrate (which fuels denitrification) and allochthonous N2O might cause enhanced concentrations of N2O. In the outer Bodden waters, nitrification may be the prevailing source of nitrous oxide, especially in summer. A preliminary estimate gives an annual emission of 58 tonnes N2O, and 960 tonnes CH4 for the whole Bodden area. Thus, Bodden waters constitute an important source methane, and a modest source of nitrous oxide in the Baltic region. |
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