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6 - Mineral economy and cycling of minerals in wetlands
- Edited by D. F. Westlake, J. Kvet, Academy of Sciences of the Czech Republic, Prague, A. Szczepanski, Polish Academy of Sciences
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- Book:
- The Production Ecology of Wetlands
- Published online:
- 27 October 2009
- Print publication:
- 21 January 1999, pp 319-366
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Summary
General characteristics of wetland habitats
Generally speaking, wetland plant communities are so dependent on the chemical processes in their submerged or waterlogged soils (or sediments) that they indicate the chemical properties of their biotopes.
The content of nutrients and other minerals in the aquatic environment depends on the chemistry of the parent rock, subsoil and soil and on the chemistry of the inflowing, running or spring waters. In wetland ecosystems that are managed or interfered with, such as fishponds and farm ponds or aquacultures, or polluted areas in river deltas and estuaries, the degree of either eutrophication or saprobity is decisive.
Wetland biotopes may be classified according to the limnological categories based on the relationship between mineral nutrient contents, and productivity (Thienemann, 1925; Naumann, 1932) as dystrophic, oligotrophic, eutrophic, auxotrophic (Björk, 1967) polluted and saprobic, etc. For the organisms in wetlands the physico-chemical environment, as a whole, is as important as the total nutrient concentration in the aquatic environment; and the ionic interactions (antagonism or reinforcement) are particularly important. A number of wetlands are distinguished by high concentrations of dissolved and suspended organic substances, which act as intense polyionic (macromolecular) buffer systems, functioning on a large scale, especially in the interstitial water of the bottom sediments. The limits of mineral nutrition are therefore not determined by the total nutrient concentrations, but by the absorption capacity of the relevant buffer system for each ion.
2 - Primary production in wetlands
- Edited by D. F. Westlake, J. Kvet, Academy of Sciences of the Czech Republic, Prague, A. Szczepanski, Polish Academy of Sciences
-
- Book:
- The Production Ecology of Wetlands
- Published online:
- 27 October 2009
- Print publication:
- 21 January 1999, pp 78-168
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- Chapter
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Summary
Introduction
The chapter is the result of co-operation between the authors. J. Květ and D.F. Westlake wrote much of the text, with the help of the contributors. The contributors researched or wrote the major part of: indirect methods, and structure and function of the assimilating organs, J.P. Ondok; quality of net production, genotypic variation and adaptations, Dagmar Dykyjová; comparisons of standing crop and productivity, E.J.P. Marshall.
Most wetlands are visually dominated by emergent vegetation, often large reeds or rushes, but the whole community of primary producers also includes substoreys of floating-leaved submerged macrophytes, periphyton, filamentous algae and phytoplankton, which may be quite important in some circumstances. The main emphasis will be on the behaviour of the dominants, but the other plants will be included where possible.
It will be assumed that the physiological features common to green plants are known and the chapter will concentrate on the special features of photosynthesis and growth by emergent plants. Submerged macrophytes, periphyton and phytoplankton are treated in more detail in the IBP-PF synthesis volume (Le Cren & Lowe-McConnell, 1980). Bradbury and Grace (1983) review primary production by Sphagnum, along with other wetland plants. Details on many of the topics discussed here, with particular reference to Phragmites australis, one of the most widespread dominant plants, will be found in Rodewald-Rudescu (1974).