Japanese Journal of Limnology最新文献_第4页

Preface “Recent advances in limnological studies of Oze mire ecosystem” 前言“鄂泽沼泽生态系统湖沼学研究新进展”

Japanese Journal of Limnology Pub Date : 2021-09-25 DOI: 10.3739/rikusui.82.149

M. Sakamoto

引用次数: 0

Interannual changes in benthic macroinvertebrate communities at the profundal bottoms of the North Basin of Lake Biwa, Japan, during 1992–2019 1992年至2019年，日本琵琶湖北部盆地深海底底栖大型无脊椎动物群落的年际变化

Japanese Journal of Limnology Pub Date : 2021-02-25 DOI: 10.3739/rikusui.82.17

A. Ohtaka, M. Nishino, E. Inoue

引用次数: 0

Evaluation of Bioavailable Radiocesium in the Sediment in Forest River and Dam Reservoir 森林河流和大坝水库沉积物中生物有效放射性铯的评价

Japanese Journal of Limnology Pub Date : 2021-02-25 DOI: 10.3739/rikusui.82.1

S. Takechi, H. Tsuji, M. Koshikawa, Shoko Ito, H. Funaki, S. Hayashi

引用次数: 3

Impact of the opening of Moriyama Dike on water quality and aquatic fauna in Honjo Area of Lake Nakaumi, Japan 森山堤防的开通对日本中海湖本条地区水质和水生动物的影响

Japanese Journal of Limnology Pub Date : 2020-09-25 DOI: 10.3739/rikusui.81.205

Masaki Kuwabara, Hiromichi Kuwabara, T. Kuwabara, Toshiaki Esumi, Y. Tabayashi, H. Kamiya, Shogo Sugahara, Yu Ishitobi

{"title":"Impact of the opening of Moriyama Dike on water quality and aquatic fauna in Honjo Area of Lake Nakaumi, Japan","authors":"Masaki Kuwabara, Hiromichi Kuwabara, T. Kuwabara, Toshiaki Esumi, Y. Tabayashi, H. Kamiya, Shogo Sugahara, Yu Ishitobi","doi":"10.3739/rikusui.81.205","DOIUrl":"https://doi.org/10.3739/rikusui.81.205","url":null,"abstract":"In May 2009, Moriyama Dike was opened in Honjo area, which lies near Lake Nakaumi along the coast of San-in District, Japan, and is isolated by two dikes for land reclamation. This study was conducted to examine the impact of the opening of the dike on water quality as well as ﬁ sh and crustacean life. We carried out a statistical analysis using monthly water-quality observations and a small catch net survey through 2004 to 2014. The analysis results showed that seawater likely flowed into Honjo, and salinity stratification developed. Furthermore, the oxygen deficient layer became thicker and progressed with prolonged duration. From the catch net survey, we found that the number of species of marine ﬁ sh greatly increased; however, no signi ﬁ cant increase in the catch per net was observed. In terms of ﬁ sh and crustacean types, the number of horse mackerel ( Trachurus japonicus ) and Taiwan blue crab ( Portunus pelagicus ) significantly increased. This was considered to be due to the easy access provided by the opening to the Sea of Japan. However, the catch of rock ﬁ sh ( Sebastes schlegeli ) and spiny goby ( Acanthogobius flavimanus ) , decreased after the opening. Because these species prefer benthic life, it was considered to have been a ﬀ ected by oxygen depletion in the lower layer of the Honjo area.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43412606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impacts of Moriyama Dike opening on the water quality in summer at Honjo area, Lake Nakaumi 森山堤开放对中海本庶地区夏季水质的影响

Japanese Journal of Limnology Pub Date : 2020-09-25 DOI: 10.3739/rikusui.81.223

Toshiaki Esumi, H. Kamiya, Toshikuni Kato, Y. Nakashima, H. Ohshiro, Shogo Sugahara, Y. Tabayashi, M. Yamamuro

引用次数: 0

Long-term changes in the number of diving ducks wintering in Lakes Nakaumi and Shinji, Japan 日本中海湖和新治湖越冬潜水鸭数量的长期变化

Japanese Journal of Limnology Pub Date : 2020-09-25 DOI: 10.3739/rikusui.81.233

Toshiaki Esumi, Toshikuni Kato, Y. Matsuo, H. Kamiya, Yu Ishitobi

{"title":"Long-term changes in the number of diving ducks wintering in Lakes Nakaumi and Shinji, Japan","authors":"Toshiaki Esumi, Toshikuni Kato, Y. Matsuo, H. Kamiya, Yu Ishitobi","doi":"10.3739/rikusui.81.233","DOIUrl":"https://doi.org/10.3739/rikusui.81.233","url":null,"abstract":"Many birds migrate during late autumn and stay until early spring at Lakes Nakaumi and Shinji in San-in district, western Honshu, Japan. The numbers of diving duck species Aythya ferina, Aythya fuligula, and Aythya marila, which constitute the majority of wintering bird populations, were determined monthly during the winter season from 1999 to 2015 in the main area of L. Nakaumi, Honjo Area, which is separated from L. Nakaumi by reclamation dikes, and L. Shinji. The mean value in December and January, obtained from changes in the monthly numbers of each diving duck in the three areas, was used as the wintering number. The long-term data showed a declining trend in the numbers of A. ferina and A. fuligula wintering in L. Nakaumi and Honjo Area. In L. Shinji, long-term data for A. fuligula also showed a decline trend, however, the data for A. marila indicated an upward trend. In L. Nakaumi and Honjo Area, the main diet for these diving duck species is the mussel Musclista senhousia, while in L. Shinji they feed on Corbicula japonica. The long-term changes in wintering bird numbers were investigated in relation to changes in food availability and habitat in the two lakes.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49366352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Estimation of pure water transparency using a calculated image 利用计算图像估计纯水的透明度

Japanese Journal of Limnology Pub Date : 2020-05-20 DOI: 10.3739/RIKUSUI.81.119

Shinya Sato

{"title":"Estimation of pure water transparency using a calculated image","authors":"Shinya Sato","doi":"10.3739/RIKUSUI.81.119","DOIUrl":"https://doi.org/10.3739/RIKUSUI.81.119","url":null,"abstract":"The transparency of pure water is the maximum of all transparencies; it is a value required for transparency analysis. However, it is difficult to determine the pure water transparency value directly through experiments, and no universal value has been obtained theoretically thus far. Therefore, the transparency of a colour image is estimated by observing it on a luminance-calibrated LCD screen that displays the tristimulus values calculated for light arriving from the direction of a Secchi disk and background. The light scattered by water molecules was approximated to the first order. For incident angles of 0°, 10°, 20°, ..., 80°, and 89°, the colour-image transparencies (CITs) were in the range of 101 ± 2.6 m to 124 ± 1.1 m. The monochromatic image transparencies (MITs) observed were similar to the research and the transparency-judgment mechanism was in the range of 95 ± 1.3 m to 117 ± 3.4 m. The total error was determined as the sum of the 95% confidence interval and trueness with respect to the transparency of light, calculated using the first-order scattering approximation. The root mean square of the relative error to CITs of the automatically determined transparency based on colour difference and threshold was 6.3 % while that to MITs based on contrast and threshold was 3.6 %. To improve the accuracy of colour-imagetransparency measurements, it is necessary to increase the order of calculating molecular scattering, improve image observation accuracy, and establish an evaluation standard. One methodology considered is to obtain an approximate pure water transparency value using a scaled-down transparency measurement experiment based on adding an absorbent to pure water.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44787291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Horizontal distribution of water quality between early and dense water plant seasons in Lake Shirarutoro, Kushiro Wetland 钏路湿地白丸郎湖早、密水草季节水质水平分布

Japanese Journal of Limnology Pub Date : 2020-05-20 DOI: 10.3739/RIKUSUI.81.137

M. Nakagawa, Miki Okamoto, M. Akasaka, N. Takamura

{"title":"Horizontal distribution of water quality between early and dense water plant seasons in Lake Shirarutoro, Kushiro Wetland","authors":"M. Nakagawa, Miki Okamoto, M. Akasaka, N. Takamura","doi":"10.3739/RIKUSUI.81.137","DOIUrl":"https://doi.org/10.3739/RIKUSUI.81.137","url":null,"abstract":"The dense growth of aquatic macrophytes can affect lake water quality. We studied the water chemistry at 40 sites on Lake Shirarutoro when dense beds of water chestnut (Trapa japonica) expanded in 2007–8. The distribution patterns between the early (June) and middle (August) vegetation water plant seasons were compared. In this lake, the dense beds of water chestnut did not necessarily correspond to the lack of dissolved oxygen at the lake bottom. Principal component analyses (PCA) of 20 variables showed that the lake could be divided into two areas: one was a central area from the main inflowing river to the outflow (‘area A’) and the other was an area adjacent to the southern wetland (‘area B’). The factor loadings of the first principal component (PC) showed high positive value for K, Ca, Na, Cl, Mg, and D-Si, and high negative for dissolved organic phosphorus (DOP), dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved iron (D-Fe). ‘Area A’ was influenced by the high concentration loading of K, Ca, Na, and Cl from a northern tributary; ‘area B’ was influenced by the adjacent wetlands. The factor loadings of the second PC showed high negative values for the total phosphorus (TP), total nitrogen (TN), volatile solids (VS), and chlorophyll a, all of which were indicators of eutrophication. The variables whose factor loading in the first PC changed between June and August were only the soluble reactive phosphorus (SRP) and SO4 . Therefore, we concluded that the distribution of the lake water chemistry was more influenced by watershed condition rather than the dense water plant beds.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46904542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Characterization of dissolved organic matter in deep groundwater by simple analytical methods applicable for small sample volumes 适用于小样本量的简单分析方法表征深层地下水中的溶解有机物

Japanese Journal of Limnology Pub Date : 2020-05-20 DOI: 10.3739/RIKUSUI.81.153

A. Mochizuki, H. Sasamoto, Daiya Bamba, Kayoko Ikigaki

{"title":"Characterization of dissolved organic matter in deep groundwater by simple analytical methods applicable for small sample volumes","authors":"A. Mochizuki, H. Sasamoto, Daiya Bamba, Kayoko Ikigaki","doi":"10.3739/RIKUSUI.81.153","DOIUrl":"https://doi.org/10.3739/RIKUSUI.81.153","url":null,"abstract":"The characterization of humic substances in groundwater is usually performed using isolated humic substances from a large volume of groundwater. However, the isolation process requires extensive time and effort, and is not feasible for small-volume samples. In this study, characterization methods available for small-volume ( approximately 1 L ) samples were applied to groundwater and surface water in the Horonobe area, Hokkaido. The methods, 3D- ﬂ uorescence analysis, gel permeation chromatography, and ion chromatography, were used to characterize dissolved organic matter ( DOM ) in the samples, including humic substances. The results indicated that the 3D- ﬂ uorescence spectrum obtained from a small volume of groundwater was similar to that obtained from isolated humic substances and showed little variation with depth. However, the peak position in surface water was di ﬀ erent from that in groundwater. Gel permeation chromatography showed that the DOM in groundwater mainly consisted of humic substances with a molecular weight of approximately 1200–2000 Da, and that the molecular weight decreased with depth. These results are consistent with the characteristics of isolated humic substances. Ion chromatography revealed that organic matter with low molecular weight was a minor component of DOM in the groundwater, which is consistent with gel permeation chromatography results. These results indicate that the methods applied in this study are useful for the characterization of DOM in groundwater using small sample volume.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":"14 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41272948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Phytoplankton community in Lake Kasumigaura: 2005 to 2019 Kasumigaura湖浮游植物群落：2005年至2019年

Japanese Journal of Limnology Pub Date : 2020-05-20 DOI: 10.3739/RIKUSUI.81.167

Y. Nagahama, T. Fukushima, T. Ouchi, Miyuki Yuzawa

{"title":"Phytoplankton community in Lake Kasumigaura: 2005 to 2019","authors":"Y. Nagahama, T. Fukushima, T. Ouchi, Miyuki Yuzawa","doi":"10.3739/RIKUSUI.81.167","DOIUrl":"https://doi.org/10.3739/RIKUSUI.81.167","url":null,"abstract":"The large shallow lake complex of Lake Kasumigaura comprises of three water bodies: Lake Nishiura, Lake Kitaura, and Lake Sotonasakaura, which are connected by three rivers. The community structure and biovolume of phytoplankton are important factors for the ecology and water quality of the lake. However, few studies have been conducted recently on the phytoplankton communities of the entire Lake Kasumigaura. The aim of this study was to clarify the changes in community structure and biovolume of phytoplankton from 2005 to 2019 in Lake Kasumigaura. The results showed that the dominant phytoplankton taxa were Bacillariophyceae from 2005 to 2007, Planktothrix ( Oscillatoriales, Cyanophyceae ) from 2008 to approximately 2010, and Bacillariophyceae since 2011. The change in the phytoplankton community structure differed between lakes Nishiura and Kitaura: the ratios of the dominant genera Cyclotella and Aulacoseira ( Centrales, Bacillariophyceae ) were higher in Nishiura than in Kitaura; the ratio of the dominant genus Synedra ( Pennales, Bacillariophyceae ) was lower in Nishiura than in Kitaura. Moreover, while the abundance of Planktothrix in Nishiura was higher than that in Kitaura, the period of Planktothrix dominance in Nishiura was shorter than that in Kitaura. The phytoplankton biovolume decreased in all three water bodies during the research period because the biovolumes of the main phytoplankton genera, Planktothrix , Cyclotella , and Cryptomonas , decreased. The values of the biodiversity indices decreased drastically in 2007 at all stations. The results suggested that Planktothrix was dominant from 2007 to 2011 across Lake Kasumigaura. Furthermore, the values of biodiversity indices increased rapidly in 2011 in Nishiura and Sotonasakaura, while the increase was slower in Kitaura.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48445740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1