A study on the role of hydraulic retention time in eutrophication of the Asahi River Dam reservoir

Kawara, Osami; Yura, Eisaku; Fujii, Shinobu; Matsumoto, Toyohisa

doi:10.2166/wst.1998.0146

Cited by 44 publications

(26 citation statements)

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“…After damming of the Asahi River in the dam phytoplankton increased due to the prolonged hydraulic retention time, and the water quality in the reservoir was usually eutrophic (Kawara et al, 1998). Nogueira (2000) also gave the similar report: higher phytoplankton diversity and abundance were associated with the contact zone between riverine and lacustrine systems towards dam in Jurumirim Reservoir (Paranapanema River).…”

Section: Discussionmentioning

confidence: 82%

Distribution of phytoplankton in the Three-Gorge Reservoir during rainy and dry seasons

Zeng

Song

et al. 2006

Science of The Total Environment

129

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Section: Discussionmentioning

confidence: 82%

Distribution of phytoplankton in the Three-Gorge Reservoir during rainy and dry seasons

Zeng

Song

et al. 2006

Science of The Total Environment

129

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“…Factors such as high water retention time in lakes and reservoirs, increased temperature, low N:P ratio, as well as surface radiation and wind conditions have been reported to influence bloom development (Carmichael 1996, Kononen et al 1996, Kawara et al 1998, Chorus & Bartram 1999. Most species preferentially occur in stable, well stratified water bodies that provide optimal conditions for their vertical migration.…”

Section: Introductionmentioning

confidence: 99%

Cyanobacterial blooms in natural waters in southern Portugal: a water management perspective

Galvão¹,

Reis²,

Valério³

et al. 2008

Aquat. Microb. Ecol.

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This synthesis of 3 studies from 2 regions of southern Portugal (Alentejo and Algarve) was part of a workshop focusing on cyanobacteria held at the SAME 10. The first study monitored impacts of the large Alqueva dam on the Guadiana estuary since 1996, revealing changes in sediment load, nutrient regime and phytoplankton succession. Prior to dam construction, dense cyanobacterial blooms occurred in the upper estuary during summer and fall. After dam construction, chlorophyll concentration, phytoplankton diversity and abundances of cyanobacteria decreased, contrary to predictions. Mycrocystins remained at low levels in the seston and undetectable in water samples, except during summer 2003 when the particulate fraction contained 1 µg l -1 , while chlorophyll concentrations and abundances of potentially toxic cyanobacteria remained low. Algarve reservoirs studied since 2001 revealed differences in phytoplankton dynamics. In the western mesotrophic reservoirs (Bravura and Funcho), 40 to 50% of surface samples contained cyanobacterial concentrations of ≥2000 cells ml -1 , while over 80% of samples from the eastern oligotrophic reservoirs (Odeleite and Beliche) exceeded this value. Spring blooms were dominated by Oscillatoriales in Odeleite and Beliche and by Chroococcales in Bravura and Funcho. Bloom composition seemed to depend on water temperature and management strategies, while toxin concentrations reflected the increased biomass of toxic species. Finally, phytoplankton communities and microcystin production in 5 Alentejo freshwater reservoirs were studied from May to December 2005 and April to July 2006. Cyanobacterial blooms occurred, with varying intensities, not only during summer but also occasionally in winter. Microcystins were detected in 23% of the samples (n = 51), but without correlation with cyanobacterial biomass. Although Microcystis aeruginosa seemed to be the major producer of microcystins, other potentially toxic species were found. In summary, the varying pattern of cyanobacterial bloom occurrence and toxicity requires a systematic approach to monitoring programs for adequate risk assessment.

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“…However, the concentrations of the main soluble nutrients in March 2004 (dry season) in the Yangtze were significantly lower than those in May 2004 (P < 0.001). Increases in phytoplankton abundance in upstream locations following dam closure have been reported in other rivers (KAWARA et al, 1998;SULLIVAN et al, 2001). Such increases are not surprising considering the decreased flow rates and longer retention times that would promote algal growth.…”

Section: Discussionmentioning

confidence: 70%

Post‐Impoundment Biomass and Composition of Phytoplankton in the Yangtze River

Zeng

Song²,

et al. 2007

International Review of Hydrobiology

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Damming, and thus alteration of stream flow, promotes higher phytoplankton populations and encourages algal blooms (density >10 6 cells L -1 ) in the Three Gorges Reservoir (TGR). Phytoplankton composition and biomass were studied in the Yangtze River from March 2004 to May 2005. 107 taxa were identified. Diatoms were the dominant group, followed by Chlorophyta and Cyanobacteria. In the Yangtze River, algal abundance varied from 3.13 × 10 3 to 3.83 × 10 6 cells L -1 , and algal biomass was in the range of 0.06 to 659 mg C m -3 . Levels of nitrogen, phosphorus and silica did not show consistent longitudinal changes along the river and were not correlated with phytoplankton parameters. Phytoplankton abundance was negatively correlated with main channel discharge (Spearman r = -1.000, P < 0.01). Phytoplankton abundance and biomass in the Yangtze River are mainly determined by the hydrological conditions rather than by nutrient concentrations.

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A study on the role of hydraulic retention time in eutrophication of the Asahi River Dam reservoir

Cited by 44 publications

References 0 publications

Distribution of phytoplankton in the Three-Gorge Reservoir during rainy and dry seasons

Distribution of phytoplankton in the Three-Gorge Reservoir during rainy and dry seasons

Cyanobacterial blooms in natural waters in southern Portugal: a water management perspective

Post‐Impoundment Biomass and Composition of Phytoplankton in the Yangtze River

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