BAN Syuhei




Research Fields, Keywords

Aquatic Ecology

Mail Address

E-mail address

Graduate School 【 display / non-display

  • Hokkaido University  Graduate School, Division of Fisheries  Doctor's Course  1991.02

Campus Career 【 display / non-display

  • University of Shiga Prefecture  School of Environmental Science  Department of Ecosystemus Studies  Professor   2008.02 - Now

  • University of Shiga Prefecture  School of Environmental Science  Department of Ecosystemus Studies  Associate Professor   2007.04 - 2008.01

  • University of Shiga Prefecture  School of Environmental Science  Department of Ecosystemus Studies  Associate Professor (as old post name)   2001.05 - 2007.03

Academic Society Affiliations 【 display / non-display

  • Association for the Sciences of Limnology and Oceanography

  • Japan Society on Water Environment

  • JpGU

Field of expertise (Grants-in-aid for Scientific Research classification) 【 display / non-display

  • Ecology/Environment

  • Aquatic bioproduction science

  • Environmental dynamic analysis


Research theme 【 display / non-display

  • Biodiversity-driven nutrient cycling and human-wellbeing in socio-ecological systems (lake ecosystem)

  • Sustainable management in lake ecosystem using macrophyte biomass

    macrophyte biomass, conservation in lake ecosystem, freshwater environments, methane fermentation, microalgal culture

  • Diversity and function of Chytrid fungi in lakes and oceans

    Chytrid fungi, diversity, phytoplankton, lakes

  • Long-term study on zooplankton biomass in Lake Biwa

    Lake Biwa, zooplankton, biomass, long-term analysis

  • Effects of internal wave on phytoplankton production in Lake Biwa

    internal wave, material flux, phytoplankton production, wind direction and speed

Papers 【 display / non-display

  • Conditions for continuous cultivation of Chlorella sorokiniana and nutrient removal from anaerobic digestion effluent of aquatic macrophytes

    Liu X., Fujiwara M., Kodera T., Watanabe K., Akizuki S., Kishi M., Koyama M., Toda T., Ban S.

    International Biodeterioration and Biodegradation  International Biodeterioration and Biodegradation  149    2020.04

    10.1016/j.ibiod.2020.104923  Joint Work  


    © 2020 Elsevier Ltd Continuous cultivations of the microalga Chlorella sorokiniana using 10-L flat-panel bioreactors were conducted at different pH levels and hydraulic retention times (HRT) under natural light conditions to accomplish the maximum algal yields and high nutrient removal from anaerobic digestion effluent (ADE) of aquatic macrophytes, which contained high concentrations of ammonium-nitrogen and phosphate-phosphorus, but less available magnesium (Mg). In subsequent experiments, Mg was enriched directly or indirectly by lowering the pH in the original ADE as source medium of a flow-through system to increase the amount of available Mg for algal growth. In the Mg-enrichment experiment, a constant maximum algal yield, 0.7 g dry-weight L−1, was obtained at HRT of 5 days, and removal efficiencies in both ammonium-nitrogen and phosphate-phosphorus were >94%. The pH-controlled experiment was conducted at HRTs of 5 and 10 days at two different pH levels (5.0 and 6.5) of the source ADE. Finally, similar algal yields and nutrient removals were obtained using source ADE at pH 6.5 and 10 days HRT as those in the Mg-enrichment experiment. We demonstrated that pH control in the source ADE through continuous cultivation at the relatively longer HRT can help to maximize algal yield and improve nutrient removal without Mg enrichment.

  • Resting eggs of the perennial copepod Eodiaptomus japonicus in Lake Biwa (Japan)

    Liu X., Ban S., Beyrend D., Dur G., Kuwae M., Makino W., Urabe J.

    Inland Waters  Inland Waters    2020.01

    10.1080/20442041.2019.1671766  Joint Work  


    © 2019, © 2020 International Society of Limnology (SIL). Egg dormancy is a key life history strategy in copepods to temporarily escape catastrophic or repetitive detrimental events and ensure permanent colonization. In Lake Biwa, although the copepod Eodiaptomus japonicus dominates the zooplankton community year-round, it has been known to produce resting eggs, yet little is known about its dormancy. To clarify the nature of dormancy in E. japonicus, we collected a sediment core from Lake Biwa, isolated resting eggs, and conducted hatching experiments to determine the life-cycle traits of the hatched individuals. We isolated 242 eggs (maximum age, 60 years) from the upper 17 cm depth sediments, and although no strict catastrophic event such as seasonal drying up was found, the findings implied that E. japonicus might have a “bet-hedging” strategy. Accumulated egg density above 17 cm was 2.5 × 104 m−2, and mean annual egg flux was 103 m−2 per year. Over the first 10 cm sediments, average egg hatching success was 17%. No egg hatchings were confirmed below 10 cm depth. Embryonic development times of the resting eggs were longer than those of subitaneous eggs, indicating that a lag phase existed until development resumed; 33% of hatched nauplii molted to adulthood, and 80% of females produced offspring. These results suggest potential recruitment from resting eggs in the bottom sediments, which partly serve as an egg bank in this copepod.

  • Nutrient removal from anaerobic digestion effluents of aquatic macrophytes with the green alga, Chlorella sorokiniana

    Kimura S., Yamada T., Ban S., Koyama M., Toda T.

    Biochemical Engineering Journal  Biochemical Engineering Journal  142   170 - 177  2019.02

    10.1016/j.bej.2018.12.001  Joint Work  


    © 2018 Elsevier B.V. Green microalgae have great potential for removing inorganic nutrients from wastewater and anaerobic digestion effluent (ADE). We investigated the cultivation conditions for maximum algal yield and nutrient (ammonium and phosphate) removal rates. The green microalga, Chlorella sorokiniana, was cultured using ADE from anaerobic digestion by two dominant macrophytes, Elodea nuttallii and Egeria densa, which cause environmental problems in Lake Biwa, Japan, because of excessive growth. Available magnesium (Mg) in the ADEs from both macrophytes was not sufficient for maximum algal growth and nutrient removal. We demonstrated that Mg-enrichment was essential for enhancing algal yield in, and nutrient removal rate from, ADEs.

  • Determining suitable submerged macrophyte biomass in terms of dissolved oxygen concentration and biodiversity in the South Basin of Lake Biwa, Japan

    Ishikawa, K., H. Haga, E. Inoue and S. Ban

     Limnology    2019.01

    Joint Work  Joint(The vice charge)

  • Planktivorous fish predation masks anthropogenic disturbances on decadal trends in zooplankton biomass and body size structure in Lake Biwa, Japan

    Liu X., Dur G., Ban S., Sakai Y., Ohmae S., Morita T.

    Limnology and Oceanography  Limnology and Oceanography    2019.01

    10.1002/lno.11336  Joint Work  


    © 2019 Association for the Sciences of Limnology and Oceanography Pelagic zooplankton samples from Lake Biwa, Japan, collected monthly since 1971, were analyzed for biomass and body size structure. Our aim was to clarify the relative effects of food availability and global warming vs. top-down control by fish predation on long-term trends. Annual mean biomass and density-weighted body size were calculated and compared with water temperature, total phosphorus (TP), as a proxy of food amount, and catch per unit effort (CPUE) of Ayu (Plecoglossus altivelis altivelis), as a proxy of planktivorous fish predation pressure. Mean water temperature above 20 m increased by 0.94°C. TP increased until 1974 and then decreased until 1985, becoming stable after that. Ayu CPUE increased until 1987 and then declined. The study period can be divided into two nutritional phases: a high TP phase (1971–1985) and a low-stable TP phase (1986–2010). Five zooplankton taxa, Eodiaptomus japonicus, Cyclopoida spp., Daphnia spp., Bosmina longirostris, and Diaphanosoma orientalis, were continuously dominant. Annual mean total crustacean biomass varied from 0.3 to 3.6 g dry weight m−2, slightly decreasing until 1993 but increasing thereafter. Generalized linear models showed that annual mean body sizes were affected by temperature and CPUE, whereas annual mean biomass was affected by TP and CPUE. These had no effect during the high TP phase, whereas only CPUE affected both traits during the low-stable TP phase. We concluded that zooplankton biomass and body size long-term trends were mostly influenced by fish predation and that eutrophication and global warming impacts might be affected by top-down control.

  • Differences in dissolved phosphate in shallow-lake waters as determined by spectrophotometry and ion chromatography

    Yi R., Song P., Liu X., Maruo M., Ban S.

    Limnology  Limnology    2019.01

    10.1007/s10201-019-00574-2  Joint Work  


    © 2019, The Japanese Society of Limnology. Phosphorus (P) plays important roles in aquatic ecosystems, but accurately determining phosphorus species (particularly bioavailable phosphate) is difficult. When phosphate concentrations are spectrophotometrically measured as soluble reactive P (SRP), the actual values are often overestimated. Ion chromatography is one method for accurately measuring orthophosphate concentrations. To clarify how the spectrophotometrical measurement overestimates actual phosphate concentrations, we compared estimates of phosphate concentrations in lake waters using both methods. SRP and orthophosphate concentrations in water samples collected from four shallow lakes around Lake Biwa, Japan, were determined monthly for 1 year by spectrophotometry and ion chromatography, respectively. SRP concentrations were frequently higher than those for orthophosphate in all lakes throughout the study period, suggesting that SRP and orthophosphate are not equivalent, although a significant relationship was found between them. Orthophosphate/SRP (ortho/SRP) ratios varied spatiotemporally in all lakes (range 0.11–1.04; mean 0.56), being well predicted by biological-mediated relevant parameters using a stepwise multiple logistic regression analysis (R 2 = 0.76). The results implied that organic matter associated with biological activity contributes to the variability in ortho/SRP ratios. Such large variability in ortho/SRP ratios emphasizes the importance of accurate orthophosphate estimates for understanding P dynamics in aquatic ecosystems.

  • Validation of a high-resolution acoustic imaging sonar method by estimating the biomass of submerged plants in shallow water

    Mizuno K., Asada A., Ban S., Uehara Y., Ishida T., Okuda N.

    Ecological Informatics  Ecological Informatics  46   179 - 184  2018.07

    10.1016/j.ecoinf.2018.07.002  Joint Work  


    © 2018 Acoustic sensing is often used for mapping and monitoring aquatic plants in shallow waters. Recently, high-resolution imaging sonar was applied to study a variety of aquatic organisms. This method can provide high-resolution, three-dimensional (3D) acoustic data on the spatial distribution of submerged plants. However, no commercial software packages are available to digitalize the images of submerged plants generated from imaging sonar data, and the high-resolution imaging sonar method has not been standardized because of a lack of empirical data. In this study, we measured the biomass of submerged plants in the north basin of Lake Biwa using high-resolution acoustic imaging sonar and compared the results to directly measured biomass values to validate the utility of high-resolution acoustic imaging sonar as a quantitative method. Biomass was calculated in 10 randomly selected quadrats (1 × 1 m) in Lake Biwa. The analysis of the resulting data indicated a strong correlation between the number of pixels in the digital images of submerged plants and their directly calculated biomass (R2= 0.91, p <.0001). The results suggest that the high-resolution imaging sonar method is a promising tool for estimating the biomass of submerged plants. Thus, this method is expected to contribute to a better understanding of aquatic ecology.

  • Fungal community structure at pelagic and littoral sites in Lake Biwa determined with high-throughput sequencing

    Song, P., S. Tanabe, R. Yi, M. Kagami, X. Liu, S. Ban

     Limnology    2018.04

    10.1007/s10201-017-0537-8  Joint Work  Joint(The vice charge)

  • Effects of temperature and nutritional conditions on physiological responses of freshwater copepod Eodiaptomus japonicus in Lake Biwa

    Liu, X. and S. Ban

     Limnological Study    2018.04

    Joint Work  Joint(The vice charge)

  • Effects of different algal diets and carbon supplies on larval development, growth and survival in the freshwater copepod Mongolodiaptomus malaindosinensis (Copepoda: Calanoida)

    Boonmak, P., X. Liu, S. Ban and L.-o. Sanoamuang

     Plankton Benthos Res.    2018.04

    Joint Work  Joint(The vice charge)

display all >>

Review Papers 【 display / non-display