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| Titel |
Influence of the kind of peat and the depth of sampling on the biochemical properties of Tagan peatland |
| VerfasserIn |
Lech Wojciech Szajdak, Lydia I. Inisheva |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038450
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| Zusammenfassung |
| The upper layer of a peat bog in which organic matter decomposes aerobically much more
rapidly than in the underlying, anaerobic catotelm. As litter accumulates at the surface the
size of the catotelm increases, because the thickness of the acrotelm is limited to depth at
which aerobic respiration can occur. Although the rate of decomposition per unit volume of
material is much greater in the acrotelm than in the catotelm, a point is reached at
which the difference in volume between the two layers is such that the total rate of
decomposition in the catotelm is equal to that in the acrotelm. This limits the thickness
to which the bog can grow. Should there be a climate change (e.g. an increase in
precipitation) growth can resume. Bogs therefore preserve a record of climatic
conditions.
Soils samples were taken from four places marked as No 1, 2, 3 and 4 each from two
depth 0-25 and 50-75 cm of the peatland Tagan. Peatlands Tagan is located near Tomsk, West
Siberia, Russia. Place No 1 in both layers represents grasses peat with the degree of the
decomposition ranged from 25 to 35% (pH 6.31-7.95). Point 2 is characterized by wooden
and wooden grasses peat with 35% degree of the decomposition (pH 5.16-9.31. There is
buckbean peat in the points 3 and 4 (pH 6.4-6.49). However, 1.5 m depth of sapropel is
located in point 4.
The activity of the following enzymes: xanthine oxidase, phenolic oxidase, peroxidase,
urease, nitrate reductase were measured and two forms of organic carbon (total organic
carbon and dissolved organic carbon) and two form of iron Fe(II) and Fe(III) were
determined in these samples. These enzymes participate in several biochemical pathways in
soil connected with redox potential. The concentrations of indole-3-acetic acid, very famous
fitohormone were also measured.
It was observed in all places of sampling significant increase of the total organic carbon
with an increase of the depth. However, the quantity of dissolved organic carbon closely
decreased with an increase of the depth, suggesting lower microbiological activity of this
level. The increase of the ratios Fe(II)/Fe(III) for place 1 and 2 and 4 and both
depth 0-25 were similar (0.56; 0.59 and 0.65) indicating similar redox properties of
these levels. Higher contents of F(III) were determined in upper layer than in lower
layer of all samples. It indicate higher oxidizing properties upper layer than lower
one
The activity of nitrate reductase, peroxidase, phenolic axidase and xanthine oxidase agree
with the content of two forms of iron in samples from all depth. In all samples was observed
the decrease of the activity of urease with an increase of the depth. It suggest higher rate
of the degradation process of urea created from the decomposition of peptides in
peat.
In sample No 1 the concentrations of indole-3-acetic acid very famous phytohormone
were similar in both determined levels. However for sample No 2, 3 and 4 the significant
decrease of the concentrations of indole-3-acetic acid with and increase of the depth of
sampling was observed.
Acknowledgements: This work was supported by a grant No. N N305 3204 36 founded
by Polish Ministry of Education and by RFFR (No.No. 09-05-00235, 09-05-00395), Minister
of Education and Science (No. 02.740.11.0325). |
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