|Effects of liming on aquatic macrophytes, with emphasis on Scandinavia|
Brandrud, T.E. (2002). Effects of liming on aquatic macrophytes, with emphasis on Scandinavia. Aquat. Bot. 73(4): 395-404
In: Aquatic Botany. Elsevier Science: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0304-3770, more
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The effects of liming on soft-water aquatic macrophytes are reviewed, based on data from the many limed lakes and rivers in Sweden and Norway. Liming usually leads to a re-establishment of acidification-sensitive species such as Fontinalis spp., Myriophyllum alterniflorum and Potamogeton spp. Most sensitive species have a critical level at pH ca. 5.5, and are believed to depend on availability of HCO3 in the water. Some more or less acidophilic bryophytes, Nardia compressa and Sphagnum auriculatum coll. have declined, and usually die when directly exposed to lime deposits. Submerged Sphagnum mats have, however, in some cases increased temporarily after liming, probably due to an increased production of CO2. The graminoid Juncus bulbosus (=J. supinus) showed a temporary massive expansion and nuisance growth in (over)limed lakes in SW Norway in the beginning of the 1990s. This extreme growth is explained by a combination of: (i) lime deposits on the sediments leading to mobilisation of CO2 and NH4; and (ii) re-acidification of the water layer, promoting high levels of CO2. In some lakes that have been limed for more than 10 years, M. alterniflorum has expanded considerably, reaching densities probably much higher than in the pre-acidification conditions. This situation is believed to be due to increased alkalinity and possibly due to eutrophication of the sediment.