|
Title |
Professor |
|
Research Fields, Keywords |
Aquatic Ecology |
|
Mail Address |
|
BAN Syuhei
|
|
|
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 】
-
Takayama Y., Hirahara M., Liu X., Ban S., Toda T.
Aquaculture Research Aquaculture Research 51 (9) 3741 - 3750 2020.09
10.1111/are.14723 Joint Work
[Abstract]
© 2020 John Wiley & Sons Ltd The understanding of the biological responses of copepods under crowding conditions contributes to establish their stable cultures at high densities for aquaculture industry, which are preferred live feeds for fish larvae. The present study investigated survivorship, fecundity, hatching success and respiration rate, of Acartia steueri raised under five densities, from 100 to 2,000 ind. L−1, to clarify the biological responses of the copepod under dense culture. There were no significant differences in survival, fecundity and hatching success among all density conditions, whereas the respiration rate at 2,000 ind. L−1 decreased by 80% as compared with a condition at 100 ind. L−1. The female copepods raised under a copepod density of >500 ind. L−1 probably invested a larger proportion of energy in reproduction in relation to total assimilated energy as compared with females under lower copepod densities. This change of energy allocation may allow A. steueri under high densities to maintain high fecundity. Acartia steueri might be a promising species for dense culture because its mortality and fecundity were independent of the effect of crowding, and the density-dependent reduction in the metabolic rate might increase reproductive investment to maintain a constant rate of reproduction even under high densities.
-
Iweh N.S., Koyama M., Akizuki S., Ban S., Toda T.
Science of the Total Environment Science of the Total Environment 730 2020.08
10.1016/j.scitotenv.2020.138993 Joint Work
[Abstract]
© 2020 Elsevier B.V. Aquatic plant biomass is characterised by high moisture content and a lignocellulose structure. To apply the anaerobic digestion (AD) treatment to aquatic plants, the simultaneous achievement of high methane (CH4) recovery per biomass volume and high biodegradability have been a challenge owing to these characteristics. Herein, we propose a novel two-stage serial wet- and solid-state AD (SS-AD) system that quickly digests the labile cytoplasm fraction in the first wet AD reactor in a short retention time while slowly digesting the lignocellulosic fraction in the later SS-AD with long retention time. In this study, the effect of this serial AD on CH4 recovery and chemical oxygen demand (COD) balance from aquatic plant biomass was examined in a semi-continuous operation. Elodea nuttallii, which grows excessively in the southern basin of Lake Biwa, Japan, was used as the substrate. For comparison, single-stage AD with different hydraulic retention times (HRTs) (30 d and 15 d) was performed. The CH4 conversion efficiency in single-stage AD deteriorated from 47.6 to 33.1% COD with shortened HRT, probably owing to the low degradability of slowly degrading fraction (i.e. lignocellulose) in the short retention time. In contrast, the serial AD under the same HRT (15 d) as a single-stage AD exhibited higher CH4 conversion efficiency of 65.1% COD, mainly owing to the enhanced degradation of slowly degrading fraction because of the prolonged solid retention time (52.2 d) of the entire system. The CH4 recovery from the wet AD alone in the serial AD system surpassed that from the 30 d-HRT of the single-stage AD, possibly due to the appropriate HRT for labile fraction and/or the microbial recirculation. The serial wet and SS-AD was suggested as a suitable technology for the treatment of aquatic plant biomass with recalcitrant cell walls and a labile cytoplasm.
-
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
[Abstract]
© 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.
-
Qian J., Liu X., Ban S., Fujiwara M., Kodera T., Akizuki S., Toda T.
Journal of Applied Phycology Journal of Applied Phycology 2020.01
10.1007/s10811-020-02196-z Joint Work
[Abstract]
© 2020, Springer Nature B.V. Green algae have great potential for removing inorganic nutrients from anaerobic digestion effluent (ADE), but there is insufficient available magnesium (Mg) in the ADE from aquatic macrophytes for effective algal growth. In this study, we determined suitable pH and hydraulic retention time (HRT) for maximizing growth of the alga Chlorella sorokiniana and nutrient removal efficiency with a flow-through continuous cultivation system. This used ADE from aquatic macrophytes, adjusted to pH 5.0, 6.0, 6.5 and 7.0 at two HRTs of 6 and 8 days. The highest C. sorokiniana biomass concentration was obtained in the pH 6.5 treatment, being 0.50 and 0.67 g L−1 at 6 and 8 days of HRT, respectively, without Mg enrichment. Both were equivalent to 83.6 mg L−1 day−1 of biomass productivity. Removal rates of both ammonium nitrogen and phosphate phosphorus were almost 100% in pH 6.5 and 7.0 treatments and declined to below 60% in pH 5.0 and 6.0 treatments during the study period. The results demonstrated that a source medium pH of 6.5 using a continuous cultivation system (irrespective of the two HRTs), and increasing available Mg, was suitable for maximizing C. sorokiniana biomass productivity and nutrient removal from the ADE.
-
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
[Abstract]
© 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.
-
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
[Abstract]
© 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)
-
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
[Abstract]
© 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.
-
Yi R., Song P., Liu X., Maruo M., Ban S.
Limnology Limnology 2019.01
10.1007/s10201-019-00574-2 Joint Work
[Abstract]
© 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.
-
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
[Abstract]
© 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.
Review Papers 【 display / non-display 】
-
Phosphorus cycling in watersheds: from limnology to environmental science
Onodera S.i., Okuda N., Ban S., Saito M., Paytan A., Iwata T.
Limnology Limnology 21 (3) 327 - 328 2020.08
10.1007/s10201-020-00631-1 Joint Work
-
Goto N., Fukuda K., Omura S., Yoshimura A., Ban S.
Japanese Journal of Limnology Japanese Journal of Limnology 78 (2) 169 - 178 2017.01
10.3739/rikusui.78.169 Joint Work