Ecological and taxonomical remarks on the desmids flora of the lower Uruguay River basin (Argentina).
Desmid assemblies along altitude gradients in Colombia.
Distributional patterns in some neotropical desmid species (Algae, Chlorophyta) in relation to migratory bird routes.
Present study aimed at testing the hypothesis that desmids present morphological variation dependent on the environment abiotic conditions mainly associated to temperature, and that such structural alterations constitute, with high frequency, 'accidents' and do not identify new species, varieties or taxonomic forms, but simply phenotypic modifications or ecoforms.
Desmids were collected both at the littoral and limnetic region of the Dom Helvecio and Carioca lakes.
Desmids were studied according to their morphological complexity and divided into simple (forms without angular processes or spines: Cosmarium and Euastrum), complex (forms with angular processes or spines: Staurastrum and Staurodesmus) and cylindrical attenuate forms (elongate and/ or filamentous forms: Closterium and Pleurotaenium).
Notwithstanding all the variations, the analysis of phytoplankton species composition at Barva's lake allowed the identification of three main phases: one dominated by small desmids
covering most part of the study period, a second characterized by the dominance of small Cryptophyta flagellates, which was similar to the composition of the phytoplankton observed in this lake in 1982 (Umana 1988), and a third phase, in between the other two, when there was a short period dominated by the colonial green alga E.
Planktonic algae other than desmids
, of three Amazonian Systems Lake (Lake Batata, Lake Mussura and Trombetas River), Para, Brazil.
81% of the total phytoplankton and was also the predominant in the class Bacillariophyceae while Netrium, a desmid
had the least biomass of 13x[10.
Food encountered included blue green algae (Spirulina, Nostoc) green algae (Mougeotia, Oedogonium), desmids (Gonatozygon, Closterium, Spirotaemaia), diatoms (Navicula, Nitschia); rotifers (Gastropus, Trichocerca), Crustacea, plant parts, insect appendages, sand grains, and snail (Melanoides tuberculata).
Desmids are more predominant in the diet during the dry season months of January to March, where they constitute 13.
Numerical abundance of blue green algae, desmids, rotifers, eggs, and unidentified materials were higher during the dry season while plant parts, crustacean, insect parts, diatoms, organic detritus, sand grains and protozoa were higher during raining season.