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Perturbations of a water column of Lake Onogawa by local heavy rainfall
Get PDF論文(Article)Abstract : The perturbations of a water column at the deepest part of Lake Onogawa by a local heavy rainfall were analyzed. Mixing throughout the water column (18.8-m deep) was indicated by changes in the distribution of water temperature. This mixing perturbed the hypolimnetic seasonal distributions of dissolved components. All particulate components peaked at 10m, suggesting a center of inflowing water. Compared with background levels, particulate nitrogen (PN), particulate carbon (PC), particulate phosphorus (PP), and suspended solids (SS) increased from 16-fold for PN to 100-fold fos SS. Soluble reactive phosphorus was the only dissolved component that formed a clear maximum at 10m, as did the particulate components. Assuming that SS consists mainly of mineral particles, SS can be classified into three categories: (1) A rapidly sinking fraction, the main body of the loaded SS, with a sinking rate exceeding 1m day~-1 and radii exceeding 2-3μm. (2) A slowly sinking fraction with a sinking speed of about 10cm day~-1 and radii of 0.7-0.9μm; this fraction is calculated to be about 4% of the total loaded SS at most. (3) A fraction that was essentially retained in the water column. The maximum estimate of this fraction was 0.5% of the total. Key words : Heavy allochthonous load・Material distribution・Ventilation・SS sinking rat
Systematic Relationship of Unicellular Red Algae: from the Phenetics to the Phylogeny
Get PDF論文(Article)The systematic relationship of the unicellular red algae based on their morphological, physiological and habitual characteristics was discussed by referring to the results of their molecular phylogenetic analyses, using 18S rRNA and psbA genes. Five groups (named as one ancestral stock; Porphyridium Group (-G) and other four groups; Rhodospora-, Rhodella-, Rhodosorus-, and Cyanidium-G) previously reported were partially supported by the molecular phylogeny which showed four phylogenetic groups. However, two of them made a clade with multicellular ones. In particular, Porphyridium-G was recognized as an ancestral stock rather than an evolutionary lineage. Consequently, the basic framework of the systematic relationship of uncellular reds has to be reconstructed, after taking new findings of molecular information into consideration. The correspondence with the phenetics and phylogenetic relationships of unicellular reds is the center of the present Mini-review. Key Words : Cyanidium, 18S rRNA, molecular phylogeny, Porphiridium, Rhodella, Rhodosorus, systematic relationship, ultrastrucuture, unicellular red alga
