Datum: 03.10.2017

Jezero Biwa - odborná přednáška

Zveme Vás na přednášku o dlohodobém vývoji kvality vody v jezeře Biwa (Japonsko). Prof. Shin-ichi Nakano navštíví Biologické Centrum AVČR v.v.i. (HBU) v rámci programu akademické výměny Mobility Plus Japonsko.

čtvrtek 5.10. 2017 13:00

Přednáškový sál, Hydrobiologický ústav přízemí, Na Sádkách 7, ČB

Dlouhodobé změny kvality vody v jezeře Biwa, zaměřeno na dynamiku organických látek a mikrobiální ekologii

Shin-ichi Nakano a kol.

(Center for Ecological Research, Kyoto University, Japonsko)

Abstrakt přednášky v angličtině:

During the last three decades, the water quality of Lake Biwa, the largest freshwater lake in Japan, has been improved through collaboration among multiple stakeholders. Mysteriously, a portion of organic matter expressed by chemical oxygen demand (CODMn) in the lake has been gradually increasing every year. Some researchers have reported that the increase in CODMn might be due to the accumulation of refractory and/or semi-labile DOM, and those DOM might be autochthonously produced. We have partly clarified the microbial processes with special reference to production of those DOM in Lake Biwa, especially in the lake’s hypolimnion. In the epilimnion of the lake, phytoplankton biomass is produced through primary production, followed by sinking into the hypolimnion. In the hypolimnion, a part of the phytoplankton biomass is converted into and produced as humic-like DOM through decomposition by planktonic bacteria. Fluorescence in situ hybridization (FISH) showed that bacterial clade, CL500-11 (phylum Chloroflexi), predominates in the hypolimnion. We made further analyses on prokaryotic community composition by high throughput 16S rRNA gene amplicon sequencing which showed the dominance by members of Planctomycetes exclusively occurred in the hypolimnion. In addition, FISH on eukaryotes showed that bacterivorous kinetoplastid flagellates are the dominant eukaryotes in the hypolimnion. So, the results indicate the presence of unique microbial food webs in the hypolimnion of Lake Biwa, where humic-like DOM is produced by the hypolimnion bacterial assemblages, and those bacteria are grazed by the dominant kinetoplastids and other hypolimnion dwelling bacterivorous protists.

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Biologické centrum AV ČR, v.v.i.
Hydrobiologický ústav
Na Sádkách 702/7
370 05 České Budějovice

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