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- Title
ECOLOGY AND BIODIVERSITY CONSERVATION OF THE ROMANIAN SYNUROPHYCEAE.
- Authors
Péterfi, Leontin Ştefan; Momeu, Laura
- Abstract
The golden-brown Synurophyceae (phylum Chromophyta) are exclusively silica-scaled, single-celled or colonial heterokont flagellates, with two families - Synuraceae and Mallomonadaceae. Both flagella are anteriorly inserted, with almost parallel bases, a longer pleuronematic flagellum, and a shorter smooth one, the latter often vestigial. The green pigments are chlorophylls a and c1, the major carotenoid being fucoxanthin. Their survival stages are siliceous, endogenous stomatocysts. Synurophyceae are characterized by external cell armour consisting of bilaterally symmetrical silica scales and sometimes also bristles (Mallomonas). Synurophyceae occur almost exclusively in freshwater plankton, being widely distributed all over the world. Not all the species are ubiquitous or cosmopolitan as formerly believed; on the contrary, some require well-defined environmental conditions (e.g. Synura sphagnicola and Mallomonas paludosa are low pH forms; Synura uvella, S. petersenii, Mallomonas acaroides, M. elongata, M. alpina are high pH forms; many others are circumneutral). Their preference towards temperature is also specific; most of them seem to be microthermal, occurring in spring and autumn, and others develop rich summer water blooms (Synura petersenii, M. elongata). Synurophyceae exhibit different distribution patterns; some are cosmopolitan, others are restricted to tropical regions, several have bipolar distribution, many are characteristic for the arctic-northern temperate zone, and some are considered endemic (M. intermedia var. saliceaensis). Silica-scaled chrysophyte populations occur mostly in spring and autumn, and belong to a given planktonic algal assemblage - "phytoplankton association" or "functional group" (cf. Reynolds). The structure of such Synurophyceae-containing phytoplankton association groups depends on the physico-chemical and biotic conditions of the habitat (temperature, light, pH, nutrients, macrophytes, zooplankton, etc.) and on the seasonal dynamics of the plankton. Therefore, it is evident that the maintenance of silica-scaled chrysophytes is possible only in self-regulating populations within natural biocoenoses, or within those less disturbed by human activities. The presence of such biocoenoses, lakes, ponds and bogs, including raised peat bogs, with outstanding Synurophyceae assemblages has been documented by the present authors in 'Mestecanisu de la Reci' (Covasna County) and near the village of Salicea (Cluj County), as well as in the Eastern and Southern Carpathians.
- Subjects
CHROMOPHYTA; MALLOMONADACEAE; CHLOROPHYLL; CAROTENOIDS; MALLOMONAS; FRESHWATER plankton; ALGAL blooms; CHRYSOPHYTES; BIODIVERSITY conservation; ALGAE ecology
- Publication
Contributii Botanice, 2009, Vol 44, p107
- ISSN
0069-9616
- Publication type
Article