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Effects of spring flood and water level draw‐down on methane dynamics in the littoral zone of boreal lakes
Author(s) -
Juutinen,
Martikainen,
Silvola
Publication year - 2001
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1046/j.1365-2427.2001.00721.x
Subject(s) - phragmites , littoral zone , environmental science , marsh , mire , water level , hydrology (agriculture) , vegetation (pathology) , flood myth , wetland , flux (metallurgy) , carex , boreal , ecology , oceanography , peat , geology , chemistry , biology , geography , medicine , cartography , geotechnical engineering , archaeology , organic chemistry , pathology
1. The annual dynamics of methane (CH 4 ) in a temporarily flooded meadow, mire bank, lacustrine sedge fen, temporarily and continuously inundated sedge ( Carex sp.) and reed ( Phragmites australis ) marshes were studied from June to November in the humic mesoeutrophic Lake Mekrijärvi and in eutrophicated parts of the mesotrophic Lake Heposelkä in the southern part of East Finland. The effects of water level and temperature on littoral CH 4 fluxes were determined. Vegetation zonation along the moisture gradient, and associated CH 4 fluxes, were evaluated. 2. The CH 4 flux increased along the moisture gradient from –0.2 to 14.2 mg CH 4 m –2 h –1 , and was highest in the permanently inundated marshes. The duration of anoxia in the sediment caused differences in the CH 4 flux. Estimated emissions for the period 1 June – 30 September in continuously inundated sparse reed and sedge marshes, drying sedge marsh, and lacustrine sedge fen were 13, 11 and 6 g CH 4 m –2 , respectively. 3. In continuously inundated vegetation, the fluxes were highest in late July/early August. The seasonal CH 4 flux pattern suggested that the fluxes were regulated by the supply of organic matter during the course of the summer and the water level. In the temporarily flooded zone, the seasonal CH 4 flux dynamics was greatly affected by changes in the lake water level, the fluxes being highest during the spring flood in early June.