N. Goto, Kaname Fukuda, Saori Omura, Aoi Yoshimura, S. Ban
Sediment oxygen demand ( SOD ) and chemical composition of the profundal zone ( ≥ 80 m water depth ) of the northern part of the North Basin of Lake Biwa, Japan were analysed to identify the mechanism of formation of large-scale oxygen-deficient waters. Sediment core samples for SOD measurements were taken from five stations ( depth of 40–95 m ) . In addition, surface sediment samples for investigation of elemental composition ( carbon, nitrogen, and phosphorus ) and origin ( autochthonous or allochthonous ) of organic matter were collected from the entire area ( 65 stations ) . The horizontal distributions of organic matter content ( g m -2 ) was almost uniform at a depth of ≥ 40 m, except for a limited zone. The percentages of organic matter ( % ) that predominantly consisted of autochthonous organic matter was higher in the profundal zone. The horizontal distribution of SOD at each measuring time was nearly uniform for all stations at a depth of ≥ 40 m, though SOD varied seasonally from 192 to 271 mgO 2 m -2 d -1 . The plausible reason for the uniform distribution of SOD at a depth of ≥ 40 m was the uniformity in organic matter composition and hypolimnion water temperature in this region. These findings suggest that oxygen dynamics in the water column above the bottom sediment greatly affects the mechanism of formation of large-scale oxygen-deficient waters.
{"title":"Sediment oxygen demand and bottom sediment environment in the northern part of the North Basin of Lake Biwa, Japan","authors":"N. Goto, Kaname Fukuda, Saori Omura, Aoi Yoshimura, S. Ban","doi":"10.3739/RIKUSUI.78.169","DOIUrl":"https://doi.org/10.3739/RIKUSUI.78.169","url":null,"abstract":"Sediment oxygen demand ( SOD ) and chemical composition of the profundal zone ( ≥ 80 m water depth ) of the northern part of the North Basin of Lake Biwa, Japan were analysed to identify the mechanism of formation of large-scale oxygen-deficient waters. Sediment core samples for SOD measurements were taken from five stations ( depth of 40–95 m ) . In addition, surface sediment samples for investigation of elemental composition ( carbon, nitrogen, and phosphorus ) and origin ( autochthonous or allochthonous ) of organic matter were collected from the entire area ( 65 stations ) . The horizontal distributions of organic matter content ( g m -2 ) was almost uniform at a depth of ≥ 40 m, except for a limited zone. The percentages of organic matter ( % ) that predominantly consisted of autochthonous organic matter was higher in the profundal zone. The horizontal distribution of SOD at each measuring time was nearly uniform for all stations at a depth of ≥ 40 m, though SOD varied seasonally from 192 to 271 mgO 2 m -2 d -1 . The plausible reason for the uniform distribution of SOD at a depth of ≥ 40 m was the uniformity in organic matter composition and hypolimnion water temperature in this region. These findings suggest that oxygen dynamics in the water column above the bottom sediment greatly affects the mechanism of formation of large-scale oxygen-deficient waters.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49309188","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}
Tomiji Hagiwara, T. Morosawa, Masahiro Kumaga, S. Nohara
Four bitterling species, Tanakia lanceolata, Acheilognathus typus, A. melanogaster and A. tabira erythropterus, are native to Lake Kasumigaura, Japan. Although their local extinction is a matter of concern, the reasons for recent population declines and their underlying mechanisms have been poorly understood. In this study, we conducted field research on the population dynamics of these species from 1999 to 2011, to determine the cause of the population decline. Special attention was paid to the ecological impact of non-native bitterlings and the availability of unionid mussels as their spawning hosts. During the study period, T. lanceolata and A. typus were not collected at all around the lake basin. Populations of A. tabira erythropterus and A. melanogaster gradually disappeared by the year 2010. In contrast, a non-native bitterling, A. macropterus, which newly invaded around the year 2000, showed steady increase in its population after 2005. Of the other non-native bitterlings, Rhodeus ocellatus ocellatus showed a population decline, while A. rhombeus was rarely found throughout the study period. Generalized additive mixed model (GAMM) analysis revealed that the non-native bitterling, A. macropterus, has no impact on native bitterling populations. Since there was a remarkable decrease in the abundance of unionids by 2006, the population decline of the native bitterlings can be attributed to the decreased availability of their spawning hosts. In spite of the unionid mussels absence, the non-native A. macropterus population expanded. It is likely that A. macropterus can utilize as its spawning host a cultivated freshwater pearl mussel, which is a hybrid between a Japanese Hyriopsis schlegeli and a Chinese H. cumingii, suggesting the possibility that its population is supported by pearl culture.
{"title":"Recent decline in native bitterling populations with reference to invasion of a non-native species, Acheilognathus macropterus , in Lake Kasumigaura, Ibaraki","authors":"Tomiji Hagiwara, T. Morosawa, Masahiro Kumaga, S. Nohara","doi":"10.3739/RIKUSUI.78.157","DOIUrl":"https://doi.org/10.3739/RIKUSUI.78.157","url":null,"abstract":"Four bitterling species, Tanakia lanceolata, Acheilognathus typus, A. melanogaster and A. tabira erythropterus, are native to Lake Kasumigaura, Japan. Although their local extinction is a matter of concern, the reasons for recent population declines and their underlying mechanisms have been poorly understood. In this study, we conducted field research on the population dynamics of these species from 1999 to 2011, to determine the cause of the population decline. Special attention was paid to the ecological impact of non-native bitterlings and the availability of unionid mussels as their spawning hosts. During the study period, T. lanceolata and A. typus were not collected at all around the lake basin. Populations of A. tabira erythropterus and A. melanogaster gradually disappeared by the year 2010. In contrast, a non-native bitterling, A. macropterus, which newly invaded around the year 2000, showed steady increase in its population after 2005. Of the other non-native bitterlings, Rhodeus ocellatus ocellatus showed a population decline, while A. rhombeus was rarely found throughout the study period. Generalized additive mixed model (GAMM) analysis revealed that the non-native bitterling, A. macropterus, has no impact on native bitterling populations. Since there was a remarkable decrease in the abundance of unionids by 2006, the population decline of the native bitterlings can be attributed to the decreased availability of their spawning hosts. In spite of the unionid mussels absence, the non-native A. macropterus population expanded. It is likely that A. macropterus can utilize as its spawning host a cultivated freshwater pearl mussel, which is a hybrid between a Japanese Hyriopsis schlegeli and a Chinese H. cumingii, suggesting the possibility that its population is supported by pearl culture.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3739/RIKUSUI.78.157","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69926686","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}
Contributions by many Japanese workers have greatly increased our knowledge of Japanese chironomid taxonomy over the last three decades. Currently, 1,206 chironomid species are recorded in Japan, but given the high diversity of natural environments, 2,000 species of chironomids are belived to be distributed in Japan. A detailed understanding of external morphological features in chironomids is one of the most important prerequisites for inferring their phylogenetic relationships. Concerning to the appendages on the gonocoxites of the hypopygia of the family Chironomidae, the term“volsellae” from Hymenoptera and named these appendages superor, inferior, and median volsellae are adopted by Sæther in 1980. Although his usage is reasonable based on the 1957 interpretation of Snodgrass, its applicability remains questionable because no distinct proof exists on whether the structures labeled as volsellae are homologous throughout the family. Instead, I recommended using terms proposed by Tokunaga in 1938 or those proposed in 1929 by Edwards for the subfamily Chironominae, as well as the neutral term accepted by Soponis in 1977 for the subfamily Orthocladiinae. Concerning the morphological terminology for the larval head, I follow Tokunaga’s interpretation in 1935.
{"title":"Further challenges in taxonomic studies of Chironomidae (Insecta, Diptera) from morphological perspective","authors":"Yamamoto Masaru","doi":"10.3739/RIKUSUI.78.51","DOIUrl":"https://doi.org/10.3739/RIKUSUI.78.51","url":null,"abstract":"Contributions by many Japanese workers have greatly increased our knowledge of Japanese chironomid taxonomy over the last three decades. Currently, 1,206 chironomid species are recorded in Japan, but given the high diversity of natural environments, 2,000 species of chironomids are belived to be distributed in Japan. A detailed understanding of external morphological features in chironomids is one of the most important prerequisites for inferring their phylogenetic relationships. Concerning to the appendages on the gonocoxites of the hypopygia of the family Chironomidae, the term“volsellae” from Hymenoptera and named these appendages superor, inferior, and median volsellae are adopted by Sæther in 1980. Although his usage is reasonable based on the 1957 interpretation of Snodgrass, its applicability remains questionable because no distinct proof exists on whether the structures labeled as volsellae are homologous throughout the family. Instead, I recommended using terms proposed by Tokunaga in 1938 or those proposed in 1929 by Edwards for the subfamily Chironominae, as well as the neutral term accepted by Soponis in 1977 for the subfamily Orthocladiinae. Concerning the morphological terminology for the larval head, I follow Tokunaga’s interpretation in 1935.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3739/RIKUSUI.78.51","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69926908","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}
{"title":"青森県六ヶ所村における湖沼の水質の長期変動(2004年～2015年)","authors":"S. Ueda, H. Hasegawa, S. Hisamatsu","doi":"10.3739/RIKUSUI.78.75","DOIUrl":"https://doi.org/10.3739/RIKUSUI.78.75","url":null,"abstract":"","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69926993","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}
Seasonal changes in the occurrence of benthic macoinvertebrates, especially of parasitoid chironomid (Polypedilum kamotertium) and the host hydropsychids (Hydropsyche orientalis and Cheumatopsyche spp.) were studied in a stream in the Tsugaru-Jūniko Lakes in northern Japan. P. kamotertium was the most dominant among more than 61 species of adult chironomids collected by means of a light-trap at the stream. Infection of larval P. kamotertium on hydropsychid pupae was found from May through September, and this period coincided with those of pupae and adults of the host hydropsychids. The results suggest that the life history of P. kamotertium is regulated by those of the host hydropsychids. The prevalence of P. kamotertium on the hydropsychid pupae ranged from 8% to 32% in the stream, thus the parasitism could make a considerable impact on host hydropsychid populations.
{"title":"Seasonal changes in the composition of aquatic macroinvertebrates in an outlet stream of Lake Ô-ike, Tsugaru Jūniko Lakes, northern Japan, with special reference to adult chironomid fauna and relationships between hydropsychid trichopterans and their parasitic chironomid, Polypedilum kamotertium","authors":"A. Ohtaka, Tadashi Kobayashi","doi":"10.3739/RIKUSUI.77.271","DOIUrl":"https://doi.org/10.3739/RIKUSUI.77.271","url":null,"abstract":"Seasonal changes in the occurrence of benthic macoinvertebrates, especially of parasitoid chironomid (Polypedilum kamotertium) and the host hydropsychids (Hydropsyche orientalis and Cheumatopsyche spp.) were studied in a stream in the Tsugaru-Jūniko Lakes in northern Japan. P. kamotertium was the most dominant among more than 61 species of adult chironomids collected by means of a light-trap at the stream. Infection of larval P. kamotertium on hydropsychid pupae was found from May through September, and this period coincided with those of pupae and adults of the host hydropsychids. The results suggest that the life history of P. kamotertium is regulated by those of the host hydropsychids. The prevalence of P. kamotertium on the hydropsychid pupae ranged from 8% to 32% in the stream, thus the parasitism could make a considerable impact on host hydropsychid populations.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69925028","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}
Mariko Yamamoto, N. Harada, Miyako Sato, K. Sugitani
In order to understand the biogeochemical characteristics of urban tidal flat sediments, distributions of organic and inorganic elements, carbon and nitrogen isotopic compositions, and their relationships with the five different fractions of phosphorous were analyzed for five cores of 15 cm long collected at the Fujimae Tidal Flat in the Port of ( n = 50 ) The Fujimae tidal flat sediments are characterized by the enrichment in Pb and Zn, with factors of 1.72 and 1.66 relative to the upper continental crustal values respectively, implying anthropologic contamination. The sediments have a C:N mole ratio of 15.1 and a 13 C value of -25.81 ‰ on average, which are almost the same as the riverine suspended particulate matter ( SPM ) . This suggests that organic matter in the sediments is largely of terrestrial origin. The results from the fraction analyses of phosphorus show that the exchangeable or loosely adsorbed P and Fe-bound P account for about 70 % of total P at the sediment surface ( 0 - 1.5 cm ) . Such available phosphorous fractions decrease by depth and remain constant at around 38 % below 6 cm from the surface. The upper layer of the sediment is likely oxidized and it can be assumed that there is a Fe-redox boundary around 6 cm depth in the sediment. In addition to exposure to the air during the ebb, the expected predominance of terrestrial organic matter with low decomposability, which would slowly consume dissolved oxygen in bottom waters and sediment interstitial waters, could play an important role for the oxidizing condition of the upper sediment.
{"title":"Biogeochemical characteristics of the Fujimae tidal flat sediments indicated by vertical distribution of elements, stable isotope ratios of carbon and nitrogen, and five types of phosphorus fractions","authors":"Mariko Yamamoto, N. Harada, Miyako Sato, K. Sugitani","doi":"10.3739/RIKUSUI.77.293","DOIUrl":"https://doi.org/10.3739/RIKUSUI.77.293","url":null,"abstract":"In order to understand the biogeochemical characteristics of urban tidal flat sediments, distributions of organic and inorganic elements, carbon and nitrogen isotopic compositions, and their relationships with the five different fractions of phosphorous were analyzed for five cores of 15 cm long collected at the Fujimae Tidal Flat in the Port of ( n = 50 ) The Fujimae tidal flat sediments are characterized by the enrichment in Pb and Zn, with factors of 1.72 and 1.66 relative to the upper continental crustal values respectively, implying anthropologic contamination. The sediments have a C:N mole ratio of 15.1 and a 13 C value of -25.81 ‰ on average, which are almost the same as the riverine suspended particulate matter ( SPM ) . This suggests that organic matter in the sediments is largely of terrestrial origin. The results from the fraction analyses of phosphorus show that the exchangeable or loosely adsorbed P and Fe-bound P account for about 70 % of total P at the sediment surface ( 0 - 1.5 cm ) . Such available phosphorous fractions decrease by depth and remain constant at around 38 % below 6 cm from the surface. The upper layer of the sediment is likely oxidized and it can be assumed that there is a Fe-redox boundary around 6 cm depth in the sediment. In addition to exposure to the air during the ebb, the expected predominance of terrestrial organic matter with low decomposability, which would slowly consume dissolved oxygen in bottom waters and sediment interstitial waters, could play an important role for the oxidizing condition of the upper sediment.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69925818","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}
K. Hirabayashi, Y. Miyabara, T. Hanazato, N. Kondo, R. Ueno, K. Takamura
In the shallow and eutrophic Lake Suwa of Central Japan, water quality has been markedly restored since the end of 1990s, and the chironomid larval community in the lake may have changed accordingly. The objectives of this study were twofold: to clarify (1) the current horizontal distribution of two chironomids, Propsilocerus akamusi and Chironomus plumosus, in Lake Suwa and (2) the genetic structure of C. plumosus in the lake. The average larval densities of P. akamusi and C. plumosus offshore in the lake were 900 and 600 individuals per m, respectively. Relative to the findings of a 2001 survey, C. plumosus larvae increased. Eight haplotypes were recognized in the cytochrome c oxidase subunit I (COI) sequences of C. plumosus larvae offshore in Lake Suwa, while more were found near the lake center. The phylogenetic tree based on the COI sequences suggests that C. plumosus specimens in Lake Suwa were of the same single lineage as those in several other Japanese lakes, while they diverged from the lineages of Russian specimens.
{"title":"Horizontal distribution of chironomid larvae and genetic structure of Chironomus plumosus population offshore in Lake Suwa, Central Japan","authors":"K. Hirabayashi, Y. Miyabara, T. Hanazato, N. Kondo, R. Ueno, K. Takamura","doi":"10.3739/RIKUSUI.78.3","DOIUrl":"https://doi.org/10.3739/RIKUSUI.78.3","url":null,"abstract":"In the shallow and eutrophic Lake Suwa of Central Japan, water quality has been markedly restored since the end of 1990s, and the chironomid larval community in the lake may have changed accordingly. The objectives of this study were twofold: to clarify (1) the current horizontal distribution of two chironomids, Propsilocerus akamusi and Chironomus plumosus, in Lake Suwa and (2) the genetic structure of C. plumosus in the lake. The average larval densities of P. akamusi and C. plumosus offshore in the lake were 900 and 600 individuals per m, respectively. Relative to the findings of a 2001 survey, C. plumosus larvae increased. Eight haplotypes were recognized in the cytochrome c oxidase subunit I (COI) sequences of C. plumosus larvae offshore in Lake Suwa, while more were found near the lake center. The phylogenetic tree based on the COI sequences suggests that C. plumosus specimens in Lake Suwa were of the same single lineage as those in several other Japanese lakes, while they diverged from the lineages of Russian specimens.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3739/RIKUSUI.78.3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69926761","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}
The purpose of this study was to examine the percent contribution of nutrient loads caused by flood events to the total annual nutrient load. We conducted daily sampling at Kandachi Bridge from July 1, 2010, to June 30, 2011, to determine the relationship between the amount of rainfall and flow volume. We examined the relationship between precipitation and flow rate and obtained a good relationship between the volume of one rainfall and runoff height using the storage function method (R = 0.87). During the study period, three rainfall events with precipitation exceeding 200 mm were observed. The rainfall from these three events accounted for 41.3% of the total annual rainfall. The increased flow caused by these three events accounted for 34.8% of the total annual flow. Total nitrogen and total phosphorus loads caused by these three events accounted for 40.7% and 62.2%, respectively, of the total annual loads. The reason that the percent contribution of phosphorus loads exceeded that of nitrogen loads is the high dependency of phosphorous loads on flow rate.
{"title":"Quantification of nutrient load caused by floods, as revealed by daily sampling: A case study of Hii River","authors":"Shogo Sugahara, Y. Tabayashi, H. Kamiya, Y. Seike","doi":"10.3739/RIKUSUI.78.97","DOIUrl":"https://doi.org/10.3739/RIKUSUI.78.97","url":null,"abstract":"The purpose of this study was to examine the percent contribution of nutrient loads caused by flood events to the total annual nutrient load. We conducted daily sampling at Kandachi Bridge from July 1, 2010, to June 30, 2011, to determine the relationship between the amount of rainfall and flow volume. We examined the relationship between precipitation and flow rate and obtained a good relationship between the volume of one rainfall and runoff height using the storage function method (R = 0.87). During the study period, three rainfall events with precipitation exceeding 200 mm were observed. The rainfall from these three events accounted for 41.3% of the total annual rainfall. The increased flow caused by these three events accounted for 34.8% of the total annual flow. Total nitrogen and total phosphorus loads caused by these three events accounted for 40.7% and 62.2%, respectively, of the total annual loads. The reason that the percent contribution of phosphorus loads exceeded that of nitrogen loads is the high dependency of phosphorous loads on flow rate.","PeriodicalId":35602,"journal":{"name":"Japanese Journal of Limnology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69927147","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}
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