Mercury methylation and demethylation in aerobic surface waters

1995 ◽  
Vol 52 (8) ◽  
pp. 1597-1608 ◽  
Author(s):  
Tuula Matilainen ◽  
Matti Verta
Keyword(s):  
Particulate Matter ◽  
Surface Waters ◽  
Mercury Methylation ◽  
Sterile Filtration ◽  
Water Layers ◽  
Formaldehyde Treatment ◽  
Forest Lakes ◽  
Water Ph ◽  
Aerobic Water ◽  
Small Forest

Potential rates of methylmercury formation and demethylation were studied in runoff waters, sediment trap material, and aerobic water layers of five small forest lakes by radioisotope methods. In addition, the roles of microbes and particulate matter in methylation and demethylation processes were examined. Methylation rates were low (≤0.12%∙d−1) in all sites studied. Water pH (4.9–6.9) had no clear effect on methylmercury formation. Methylation took place in filtered water (nominal pore size 0.2 μm) and in formaldehyde-treated or autoclaved samples, but was strongly suppressed by both dissolved organic matter (color) and particulate matter. Demethylation rates in surface waters (≤13.2%∙d−1) were decreased by low temperatures and the process was blocked by sterile filtration, formaldehyde treatment, and autoclaving. The results indicate that mercury methylation in aerobic humic waters is an accidental process caused by bacterial exoenzymes or other dissolved compounds. Methylmercury demethylation was clearly microbial in nature.

scholarly journals Comparison of dry and wet deposition of particulate matter in near-surface waters during summer

PLoS ONE ◽  
2018 ◽  
Vol 13 (6) ◽  
pp. e0199241 ◽  
Author(s):  
Yanan Wu ◽  
Jiakai Liu ◽  
Jiexiu Zhai ◽  
Ling Cong ◽  
Yu Wang ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Surface Waters ◽  
Wet Deposition ◽  
Near Surface ◽  
Dry And Wet Deposition

scholarly journals Prominent bacterial heterotrophy and sources of <sup>13</sup>C-depleted fatty acids to the interior Canada Basin

2013 ◽  
Vol 10 (11) ◽  
pp. 7065-7080 ◽  
Author(s):  
S. R. Shah ◽  
D. R. Griffith ◽  
V. Galy ◽  
A. P. McNichol ◽  
T. I. Eglinton
Keyword(s):  
Fatty Acids ◽  
Particulate Matter ◽  
Organic Carbon ◽  
Suspended Particulate Matter ◽  
Surface Waters ◽  
Canada Basin ◽  
The Arctic ◽  
Deep Basin ◽  
Suspended Particulate ◽  
Chemoautotrophic Bacteria

Abstract. In recent decades, the Canada Basin of the Arctic Ocean has experienced rapidly decreasing summer sea ice coverage and freshening of surface waters. It is unclear how these changes translate to deeper waters, particularly as our baseline understanding of organic carbon cycling in the deep basin is quite limited. In this study, we describe full-depth profiles of the abundance, distribution and carbon isotopic composition of fatty acids from suspended particulate matter at a seasonally ice-free station and a semi-permanently ice-covered station. Fatty acids, along with suspended particulate organic carbon (POC), are more concentrated and 13C-enriched under ice cover than in ice-free waters. But this influence, apparent at 50 m depth, does not propagate downward below 150 m depth, likely due to the weak biological pump in the central Canada Basin. Branched fatty acids have δ13C values that are similar to suspended POC at all depths and are more 13C-enriched than even-numbered saturated fatty acids at depths above 3000 m. These are likely to be produced in situ by heterotrophic bacteria incorporating organic carbon that is isotopically similar to total suspended POC. Below surface waters, there is also the suggestion of a source of saturated even-numbered fatty acids which could represent contributions from laterally advected organic carbon and/or from chemoautotrophic bacteria. At 3000 m depth and below, a greater relative abundance of long-chain (C20–24), branched and unsaturated fatty acids is consistent with a stronger influence of re-suspended sedimentary organic carbon. At these deep depths, two individual fatty acids (C12 and iso-C17) are significantly depleted in 13C, allowing for the possibility that methane oxidizing bacteria contribute fatty acids, either directly to suspended particulate matter or to shallow sediments that are subsequently mobilized and incorporated into suspended particulate matter within the deep basin.

Carbon dioxide efflux and ecosystem metabolism of small forest lakes

2019 ◽  
Vol 82 (1) ◽  
Author(s):  
Kenneth Thorø Martinsen ◽  
Theis Kragh ◽  
Kaj Sand-Jensen
Keyword(s):  
Carbon Dioxide ◽  
Ecosystem Metabolism ◽  
Forest Lakes ◽  
Carbon Dioxide Efflux ◽  
Small Forest

Autumnal and vernal circulation of small forest lakes in Southern Finland

1984 ◽  
Vol 22 (1) ◽  
pp. 103-107 ◽  
Author(s):  
K. Salonen ◽  
L. Arvola ◽  
M. Rask
Keyword(s):  
Forest Lakes ◽  
Small Forest

Short- and long-term patterns of 137Cs in fish and other aquatic organisms of small forest lakes in southern Finland since the Chernobyl accident

2012 ◽  
Vol 103 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Martti Rask ◽  
Ritva Saxén ◽  
Jukka Ruuhijärvi ◽  
Lauri Arvola ◽  
Marko Järvinen ◽  
...  
Keyword(s):  
Chernobyl Accident ◽  
Aquatic Organisms ◽  
Forest Lakes ◽  
Short And Long Term ◽  
Small Forest

scholarly journals A Statistical Model for Estimation of Ichthyofauna Quality Based on Water Parameters in Oituz Bazin

2015 ◽  
Vol 17 (1) ◽  
pp. 85-94
Author(s):  
Carmen Popescu ◽  
Dorel Ureche ◽  
Camelia Ureche ◽  
Elena Nechita
Keyword(s):  
Statistical Model ◽  
Surface Waters ◽  
Food Source ◽  
Important Food ◽  
Biometric Data ◽  
Water Parameters ◽  
The People ◽  
Water Ph ◽  
Important Food Source

Abstract Fish represents an important food source for people worldwide. Moreover, although considered a very old occupation, fishing continues to provide jobs, especially for the people living in the coastal countries. The quality of surface waters affects the quality of fish as a food source. For this reason, the present study aims to assess the quality of the ichthyofauna in the Oituz River and some of its tributaries using several parameters that have been computed based on the biometric data of the biological material gathered during 2004-2008, in correlation with the water pH and water temperature. The present paper also highlights some observations regarding the changes of the analyzed ecosystems, as well as some recommendations regarding the fish consumption in the studied basin, considered as a food source for humans.

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