Artikkelit kirjoittajalta Edgar Karofeld
Patterns in Estonian bogs as depicted in color kite aerial photographs.
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Kite aerial photography (KAP) was conducted at three bogs in east-central and southwestern Estonia to further investigate the possibilities of this technique for mire research. Color-visible and color-infrared photographs were acquired in all orientations with film and digital cameras. Individual objects can be identified in vertical photographs in the size range 10 to 30 cm, which allows for microstructural investigations. Color-visible photographs reveal distinct color and texture zones in the vegetation cover of bogs, and water pools form a strong contrast with emergent vegetation. The intricate patterns of emergent, floating and submerged vegetation are portrayed clearly, and the boundary is defined sharply between emergent and floating moss at pool margins. Distinct color and texture zones of plant cover represent specific vegetation communities. Color-infrared photographs depict active photosynthesis of floating and emergent moss (Sphagnum sp.) in narrow zones (1–2 m wide) at pool margins. The high level of photosynthesis in such narrow zones may have significant implications for development of bog morphology, biomass accumulation, methane emission, and other environmental factors. Numerous small water bodies are more abundant than anticipated and may be more common than is generally recognized on conventional airphotos or satellite images. Multi-view angle imagery displays considerable variations in reflectivity of bog cover materials for different viewing directions. Special lighting effects, such as sun glint and the hot spot, are more prominent in color-infrared pictures, because of darker shadows. Our field experience demonstrates that kite aerial photographs may provide a basis for microstructural mapping and analysis of complex bogs within a multi-scale approach to mire investigations.
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Aber,
Earth Science Department, Emporia State University, Emporia, Kansas 66801 U.S.A.
Sähköposti:
ei.tietoa@nn.oo
- Aaviksoo, Sähköposti: ei.tietoa@nn.oo
- Karofeld, Sähköposti: ei.tietoa@nn.oo
- Aber, Sähköposti: ei.tietoa@nn.oo
Emäksisen tuhkalaskeuman vaikutus rahkasammaliin Niinsaarensuolla Koillis-Virossa.
English title: The effects of alkaline fly ash precipitation on the Sphagnum mosses in Niinsaare bog, NE Estonia.
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In north-east Estonia the precipitation of calcium-rich strongly alkaline fly ash from thermal power stations has caused significant changes in the local ombrotrophic mires. Sphagnum mosses disappeared from Niinsaare bog during the 1970s in the period of the highest air pollution. Their disappearance was probably caused mainly by the combination of high pH values and an increased concentration of calcium in the bog water. In Niinsaare bog, the present mean pH value of bog water is 5.3 ± 0.6 and the mean calcium concentration 11.6 ± 1.6 mg l-1, compared with 3.7 ± 0.4 and 1.9 ± 0.2 mg l-1 in the uncontaminated Nigula bog respectively. During the last decade, following the reduction of fly ash emission, the Sphagnum mosses started to reappear in Niinsaare bog. Nine Sphagnum patches dominated mainly by S. angustifolium, S. fallax and S. magellanicum were studied from June 1991 to September 1995. During one year, the distance between the centre and edges of these patches increased on an average by 5.1 ± 2.7 cm and the area by 29 ± 21.5 %. This indicates that the degeneration of Sphagna in NE Estonian bogs is not yet irreversible and, by reducing the air pollution in long term, the restoration of Sphagnum carpet is possible.
Key words: atmospheric pollution, degeneration and recurrence of Sphagna, ombrotrophic mire.
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Karofeld,
Institute of Ecology, Kevade Str. 2, EE0001 Tallinn, Estonia
Sähköposti:
ei.tietoa@nn.oo
First impressions and findings on Sphagnum Mosses – The Stars of European Mires.
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Karofeld,
University of Tartu
Sähköposti:
edgar.karofeld@ut.ee
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