Sterols, normal alkanols, normal alkanoic acids, chlorophyll like substances, total lipid carbon, total organic carbon and C/N in the core sediment of Lake Suwa were determined. The profile of the relative abundances of these lipid compounds seemed to reflect a history of production rate in the lake during about 20 years.Article信州大学理学部付属諏訪臨湖実験所報告 7: 41-46(1991)departmental bulletin pape

Hayashi,  H.

Ogura,  K.

English

Sterols, normal alkanols, normal alkanoic acids, chlorophyll like substances, total lipid carbon, total organic carbon and C/N in the core sediment of Lake Suwa were determined. The profile of the relative abundances of these lipid compounds seemed to reflect a history of production rate in the lake during about 20 years

Ogura  K.

Hayashi  H.

Shinshu University Institutional Repository

Rep, Stt,va H.ydrobioL, 7; 41-46 (199ij 41CHANGE OF TROPHIC STATUS IN LAKE SUWA DURIN`G 20YEARS-ELUCIDATION BY RELATIVE ABUNDANCES OF LIPID COMPOUNDS INSEDIMENTS-Ogura, K. and Hayashi H.1) Faculty of Science, Tokyo Metropolitan University,   2-1-1, Fukasawa, Setagayaku, Tokyo 158 Japan2) Faculty of Science, Shinshu University,   Matsumoto 390 JapanABSTRACT Sterols, normal alkanols, normal alkanoic acids, chlorophyli like substances,total lipid carbon, total organic carbon and CIN in the core sediment of LakeSuwa were determined. The profile of the relative abundances of these lipidcompounds seemed to reflect a history of production rate in the lake during about20 years.key words Lake Suwa, lipid coinpounds, sediment, history, eutrophicationINTRODUCTION Sediments in lakes have good information about paleoenvironments in the lakes.Absolute contents and relative abundance of lipid compounds provide theinformation on primary production rates and other biological aspects, Theauthors have reported the relationship between chlorophyll like derivatives andthe glacial periods(1,2) and other environments(3) by usiRg a 14oo rr} long coreof Lake Biwa. Mpid classes iR sediraents of contemporary five lakes have wellimplicated the concentrations of nutrients ln lake water and the preductionrates(4). Lake Suwa is now highly eutrophicated. But it is reported that the water qualityimproves since the Sewage Treatment Plant began to work about 20 yearsago(5). The object of this study is to examine the improvement ef the water quality ofLake Suwa by the relative abundances vf various lipid compounds, total organiccarbon and C!N.MATERIALS AND METHODS42 Four 16 cm core sediment were taken frem the deepest area of Lake Suwa, 7 min water depth, on November 13, 1987. Lipids in the wet sediment samples of every 4 cm in length (composites of the 4core samples) were extracted with chloroformlmethanol(211), followed bywashing the mixtures with redistilled water. The liplds were then dissolyed intochloroform. Lipid classes were analyzed by TLC!FID analyzer(IATROSCAN HT-10,IATRON, Japan)(4). Total organic carbon and nitrogen were analyzed by CHNCORDER(YANACO MT-3, YANAGIMOTO). Radioactivity of 137Cs in thesediments was determined by a Ge y-ray spectropaeter(ORTEC Ge y-rayafialyzer).Analytical methods of lipid compounds were the same as described before(3).RESULTS AND DISCUSSION The vertical distributions of total organic carbon(TOC), C/N(weight ratio), totaliipid carbon(TLC), and TLC/TOC in the samples are shown in Fig. 1. The lowvalue of CIN, high abundances of TOC and TLC, and TLCfTOC at 8 - 12 cm incore depth relative to other layers, seem to indicate the higher production rate atthe deposition period.oAE O-4.El･A.- 4-8Sv 8-12.Qo12- 16UTOC( ele)5C/' N8 10 120TLC TLC/TOC(mgig) xio-3'Fig. 1. Vertica] dfistribution of concentrations of totalorganic carbon(TOC), and totBl ]ipid carbon(TLC), andC!N(weight ratq'o) and TLCITOC in core sediments of Lake Suwa.43 In Fig.2, ratios of contents of shorter chain, to lofiger chain even n-alkanol(£C14+Ci6+C18)/(£C20+C22+C24+C26+C28), and n-alkanoic acids(£Cl2 t-C19)f(£C20 - C32) and ratios of contents of phytol to most abundaRt n-alkanol.EevenALNE O-4UE4-8"a-'vdr 8-12o612-16UEeven 2oN 2sO O.5       FA  'IE;2Lj}illl-'2Li);`2o 32  phytoUMAPAFig. 2. Ratios of shorter chain to ]onger chain of n--alkanol(XCiu+Ci6+C!s)!(£C2o+C22+C2lj÷C26+C2a) and n-alkanoic acids(ZCi2 'V Cig)!(ZC2o rv C32), and ratios of phytol to most        n--alkanol(MAPA) veysus core depth.abundant The ratios of alkanols aRd alkanoic acids indicate relative contribution degreefrom autochthonous to allochthonous origin. The highest value was obtained inthe sample, 8 ･- 12 cm, thougk it seems to increase recently again. Free phytolwas rarely present in those samples. Therefore phytol obtained by alkalinehydrolysis, is considered to be derived from chlorophylls and their derivatiyes.Phytol is generally decomposed with time iR water column and sediments. Thehighest ratio of phytol to the most abundant alkaRol found in the 8 ･- 12 cm,suggests the presence of turbulence of sediments by benthos(bioturbation) andwinds. However vertlcal distributions of metals, such as Cu, Zn and Pb in severalcore sediments, which were taken in Dec.1987(6), show similar pattems to thissamples and also the improvement of water qualities in Lake Suwa after theconstruction of TreatmeRt System(5) supported the verdcal profile.  From those facts, the presence of bieturbation was denied and the mosteutrophicated layer, 8 '- 12 cm was estimated to be buried in 1977 '- 1979, whenthe treatmeitt plant began to work. The sedimentation rate is estimated to be 1cmlyear t- 1.5 cm/year. This value is about three times that of Lake Aoki, Lake44Nakatsuna and Lake Kizaki which was determined by conceRtrations 'of 137Cs.  ln Fig. 3, ratios of 24--methylcholesta-5,22-dien-3fi-ol(A22C28), 24-methylchlolest-5-en-3S-ol(C28), and choles'terol(C27) with their corresponding5a--stanols to 24-ethylcholest-5-en-3fi-ol(C29) with their corresponding.5a--stanolare shown. The figure also includes ratios of totals of these 4 5oc-staRols to totaisof 4 A5sterols(stanol/A5).AE.Sl.?SvokoUO-- 44- 88-1212-16  A22cl2slC2g C2s/C29   927iC2g stanou65Fig. 3. Ratios of sterols, 24-methylcholesta--5,22-dien-3B-ol24-methylcholest-5-en--3B-ol and cholestero] to 24--ethylcholest-5--en-･3B-ol, and 5ct-stanols to stenols versus core depth. A22C2e: 24--methylcholesta-5,22-dien--3B-ol + 5ct-stanol.   C2e: 24--methy}cholest--5--en-3B-ol + 5or-stanol.   C27: cholesterol + 5ct-stanol.   C2g: 24-ethylcholest-5-en-3B--ol -+- 5et-stanol. stanols: summation of four 5or-stanols.   A5 : suramation of four stenols.  Sterols are good biomarkers. A22C28 is abundaRt in diatoms such asAsterionella(4). C29 is abundant in higher plants, C28 is present in seyeralplankton aRd also in soils. C27 is abundant in zooplankton but in polluted area,C27 is derived frora untreated sewages. Ratie C27!C29 in contemporary sedimentsand a 1400 m long core of Lake Biwa, correlated to CIN except fbr heavilypolluted area, such as in Lake Suwa(4). High values of C27!C29 in O t- 4 cm aRd 845-- 12 cm indicate anthropogenic pollutlon includ}ng animal farming. Re}atiyelyhigher ratios of A22C28!C29 and C28fC29 found in 8 - 12 cm indicate higherproduction rates of diatoms and green algae ancYor cyanobacteria, respectively. The highest ratio of stafiollA5 was fbund in 8 N 12 cm. The higher ratiolndicates relatively anoxic sedimentary environments, and generally increaseswith depth. However the extraordinary high value at 8 "- 12 cm layer shows theIarge sedimentation rate and also explains the relatively iarge araount of totailipid carbon, and highest relative abundances of hydrocarbons and free fatty acidsln total lipid carbon, separated on TLC-FID. The hydrocarbon fraction containsunresolved corr}plex mixtures which is characteristics of oil pollution. Fatty acidsare consisted of shorter chain acids which are indicative of living organisms. Itproved that phytol is likely preserved in these anoxic sedimentary environments. This study is a part of comparative study of lipid compounds in core sedimentsof several contemporary lakes with different environments: contents of nutrieRtsin lake water, water depth, lake size, lake laistory, and others. The details of thestudy will be published elsewhere.CONCLUSION The improvement of water qualities in Lake Suwa by the construction of theTreatment Plant in 1979 was confirmed by determination of lipid compounds insediments.1.The presence of bioturbation iR sediments was denied.2,Relatively large amounts of total organic carbon and total lipid carbon, andrelatively low ratio of C/N(weight ratio) to that in other layers were found in 8 -･12 cm sample.3.The sample, 8 - 12 cm, seems to correspond to deposits just before theconstructioR of the Treatment System in 1979.The sedimentation rate is estimatedto be 1 cmlyear - 1.5 cmlyear.4.Biomarkers characteristic of autochthonous origin are relatively abundant inthe sample, 8 -- 12 cm.5.Anthropogenic molecules are relatively abundant in the sample, 8 - 12 cm.6.Anoxic sedirnentary environment at 8 -･ 12 cm, tends to change to oxiccondition.7.ProductioR rates seerns to decrease from 1979 but tend to increase these fewyears. Is this the effects of the increasing Solar Activity, the Global Warming andthe increasing of the atrnospheric carbon dioxide or is there anything else?REFERENCES1. 0gura, K. (1988) Organic compounds in a Lake Biwa sediment core of 1400 m, Verh. bztemat. iVerein. Limnol. 23:887-892.462, Ogura, K., Hisatake, J. and Ishimura, M. (1985) Chloroform  extractable substances in a 1400 m-core sample of Lake Biwa, I,  Chlorophyll-like substances and total extractable carbon. A preliminary study. Proc. lapan Aced. 61 B:411-414.3. 0gura, K, Machihara, T. and Takada, H. (1990) Diagenesis of biomarkers iR Biwa Lake sedimefits over 1 million years.  Advances in Organic Geochemistry 1989 Org. Geoclzem. 16:(in  press).4. 0gura, K, (1990) Lipid compouRds in lake sediments.  Verh, hitemqt. Verein. Limnol. 24:(in press). -5. 0kino, T. and Members of Routine Observation Group, Lake Suwa  (1990) Water' management and monitoring of Lake Suwa.  .ipn, uTL LimnoL 51:17--23.6. Terashima, S., Inouchi, Y., Nakao, S. and Yonetani, H. (1990)  Geochemistry of 14 elements in bottom sediments from Lake Suwa,  Central Japan. Bull, Geol. Surv. Japan41:147-172.

CHANGE OF TROPHIC STATUS IN LAKE SUWA DURING 20 YEARS -ELUCIDATION BY RELATIVE ABUNDANCES OF LIPID COMPOUNDS IN SEDIMENTS-

Rep, Stt,va H.ydrobioL, 7; 41-46 (199ij 41CHANGE OF TROPHIC STATUS IN LAKE SUWA DURIN`G 20YEARS-ELUCIDATION BY RELATIVE ABUNDANCES OF LIPID COMPOUNDS INSEDIMENTS-Ogura, K. and Hayashi H.1) Faculty of Science, Tokyo Metropolitan University,   2-1-1, Fukasawa, Setagayaku, Tokyo 158 Japan2) Faculty of Science, Shinshu University,   Matsumoto 390 JapanABSTRACT Sterols, normal alkanols, normal alkanoic acids, chlorophyli like substances,total lipid carbon, total organic carbon and CIN in the core sediment of LakeSuwa were determined. The profile of the relative abundances of these lipidcompounds seemed to reflect a history of production rate in the lake during about20 years.key words Lake Suwa, lipid coinpounds, sediment, history, eutrophicationINTRODUCTION Sediments in lakes have good information about paleoenvironments in the lakes.Absolute contents and relative abundance of lipid compounds provide theinformation on primary production rates and other biological aspects, Theauthors have reported the relationship between chlorophyll like derivatives andthe glacial periods(1,2) and other environments(3) by usiRg a 14oo rr} long coreof Lake Biwa. Mpid classes iR sediraents of contemporary five lakes have wellimplicated the concentrations of nutrients ln lake water and the preductionrates(4). Lake Suwa is now highly eutrophicated. But it is reported that the water qualityimproves since the Sewage Treatment Plant began to work about 20 yearsago(5). The object of this study is to examine the improvement ef the water quality ofLake Suwa by the relative abundances vf various lipid compounds, total organiccarbon and C!N.MATERIALS AND METHODS42 Four 16 cm core sediment were taken frem the deepest area of Lake Suwa, 7 min water depth, on November 13, 1987. Lipids in the wet sediment samples of every 4 cm in length (composites of the 4core samples) were extracted with chloroformlmethanol(211), followed bywashing the mixtures with redistilled water. The liplds were then dissolyed intochloroform. Lipid classes were analyzed by TLC!FID analyzer(IATROSCAN HT-10,IATRON, Japan)(4). Total organic carbon and nitrogen were analyzed by CHNCORDER(YANACO MT-3, YANAGIMOTO). Radioactivity of 137Cs in thesediments was determined by a Ge y-ray spectropaeter(ORTEC Ge y-rayafialyzer).Analytical methods of lipid compounds were the same as described before(3).RESULTS AND DISCUSSION The vertical distributions of total organic carbon(TOC), C/N(weight ratio), totaliipid carbon(TLC), and TLC/TOC in the samples are shown in Fig. 1. The lowvalue of CIN, high abundances of TOC and TLC, and TLCfTOC at 8 - 12 cm incore depth relative to other layers, seem to indicate the higher production rate atthe deposition period.oAE O-4.El･A.- 4-8Sv 8-12.Qo12- 16UTOC( ele)5C/' N8 10 120TLC TLC/TOC(mgig) xio-3'Fig. 1. Vertica] dfistribution of concentrations of totalorganic carbon(TOC), and totBl ]ipid carbon(TLC), andC!N(weight ratq'o) and TLCITOC in core sediments of Lake Suwa.43 In Fig.2, ratios of contents of shorter chain, to lofiger chain even n-alkanol(£C14+Ci6+C18)/(£C20+C22+C24+C26+C28), and n-alkanoic acids(£Cl2 t-C19)f(£C20 - C32) and ratios of contents of phytol to most abundaRt n-alkanol.EevenALNE O-4UE4-8"a-'vdr 8-12o612-16UEeven 2oN 2sO O.5       FA  'IE;2Lj}illl-'2Li);`2o 32  phytoUMAPAFig. 2. Ratios of shorter chain to ]onger chain of n--alkanol(XCiu+Ci6+C!s)!(£C2o+C22+C2lj÷C26+C2a) and n-alkanoic acids(ZCi2 'V Cig)!(ZC2o rv C32), and ratios of phytol to most        n--alkanol(MAPA) veysus core depth.abundant The ratios of alkanols aRd alkanoic acids indicate relative contribution degreefrom autochthonous to allochthonous origin. The highest value was obtained inthe sample, 8 ･- 12 cm, thougk it seems to increase recently again. Free phytolwas rarely present in those samples. Therefore phytol obtained by alkalinehydrolysis, is considered to be derived from chlorophylls and their derivatiyes.Phytol is generally decomposed with time iR water column and sediments. Thehighest ratio of phytol to the most abundant alkaRol found in the 8 ･- 12 cm,suggests the presence of turbulence of sediments by benthos(bioturbation) andwinds. However vertlcal distributions of metals, such as Cu, Zn and Pb in severalcore sediments, which were taken in Dec.1987(6), show similar pattems to thissamples and also the improvement of water qualities in Lake Suwa after theconstruction of TreatmeRt System(5) supported the verdcal profile.  From those facts, the presence of bieturbation was denied and the mosteutrophicated layer, 8 '- 12 cm was estimated to be buried in 1977 '- 1979, whenthe treatmeitt plant began to work. The sedimentation rate is estimated to be 1cmlyear t- 1.5 cm/year. This value is about three times that of Lake Aoki, Lake44Nakatsuna and Lake Kizaki which was determined by conceRtrations 'of 137Cs.  ln Fig. 3, ratios of 24--methylcholesta-5,22-dien-3fi-ol(A22C28), 24-methylchlolest-5-en-3S-ol(C28), and choles'terol(C27) with their corresponding5a--stanols to 24-ethylcholest-5-en-3fi-ol(C29) with their corresponding.5a--stanolare shown. The figure also includes ratios of totals of these 4 5oc-staRols to totaisof 4 A5sterols(stanol/A5).AE.Sl.£SvokoUO-- 44- 88-1212-16  A22cl2slC2g C2s/C29    927iC2g stanou65Fig. 3. Ratios of sterols, 24-methylcholesta--5,22-dien-3B-ol24-methylcholest-5-en--3B-ol and cholestero] to 24--ethylcholest-5--en-･3B-ol, and 5ct-stanols to stenols versus core depth. A22C2e: 24--methylcholesta-5,22-dien--3B-ol + 5ct-stanol.   C2e: 24--methy}cholest--5--en-3B-ol + 5or-stanol.   C27: cholesterol + 5ct-stanol.   C2g: 24-ethylcholest-5-en-3B--ol -+- 5et-stanol. stanols: summation of four 5or-stanols.   A5 : suramation of four stenols.  Sterols are good biomarkers. A22C28 is abundaRt in diatoms such asAsterionella(4). C29 is abundant in higher plants, C28 is present in seyeralplankton aRd also in soils. C27 is abundant in zooplankton but in polluted area,C27 is derived frora untreated sewages. Ratie C27!C29 in contemporary sedimentsand a 1400 m long core of Lake Biwa, correlated to CIN except fbr heavilypolluted area, such as in Lake Suwa(4). High values of C27!C29 in O t- 4 cm aRd 845-- 12 cm indicate anthropogenic pollutlon includ}ng animal farming. Re}atiyelyhigher ratios of A22C28!C29 and C28fC29 found in 8 - 12 cm indicate higherproduction rates of diatoms and green algae ancYor cyanobacteria, respectively. The highest ratio of stafiollA5 was fbund in 8 N 12 cm. The higher ratiolndicates relatively anoxic sedimentary environments, and generally increaseswith depth. However the extraordinary high value at 8 "- 12 cm layer shows theIarge sedimentation rate and also explains the relatively iarge araount of totailipid carbon, and highest relative abundances of hydrocarbons and free fatty acidsln total lipid carbon, separated on TLC-FID. The hydrocarbon fraction containsunresolved corr}plex mixtures which is characteristics of oil pollution. Fatty acidsare consisted of shorter chain acids which are indicative of living organisms. Itproved that phytol is likely preserved in these anoxic sedimentary environments. This study is a part of comparative study of lipid compounds in core sedimentsof several contemporary lakes with different environments: contents of nutrieRtsin lake water, water depth, lake size, lake laistory, and others. The details of thestudy will be published elsewhere.CONCLUSION The improvement of water qualities in Lake Suwa by the construction of theTreatment Plant in 1979 was confirmed by determination of lipid compounds insediments.1.The presence of bioturbation iR sediments was denied.2,Relatively large amounts of total organic carbon and total lipid carbon, andrelatively low ratio of C/N(weight ratio) to that in other layers were found in 8 -･12 cm sample.3.The sample, 8 - 12 cm, seems to correspond to deposits just before theconstructioR of the Treatment System in 1979.The sedimentation rate is estimatedto be 1 cmlyear - 1.5 cmlyear.4.Biomarkers characteristic of autochthonous origin are relatively abundant inthe sample, 8 -- 12 cm.5.Anthropogenic molecules are relatively abundant in the sample, 8 - 12 cm.6.Anoxic sedirnentary environment at 8 -･ 12 cm, tends to change to oxiccondition.7.ProductioR rates seerns to decrease from 1979 but tend to increase these fewyears. Is this the effects of the increasing Solar Activity, the Global Warming andthe increasing of the atrnospheric carbon dioxide or is there anything else?REFERENCES1. 0gura, K. (1988) Organic compounds in a Lake Biwa sediment core of 1400 m, Verh. bztemat. iVerein. Limnol. 23:887-892.462, Ogura, K., Hisatake, J. and Ishimura, M. (1985) Chloroform  extractable substances in a 1400 m-core sample of Lake Biwa, I,  Chlorophyll-like substances and total extractable carbon. A preliminary study. Proc. lapan Aced. 61 B:411-414.3. 0gura, K, Machihara, T. and Takada, H. (1990) Diagenesis of biomarkers iR Biwa Lake sedimefits over 1 million years.  Advances in Organic Geochemistry 1989 Org. Geoclzem. 16:(in  press).4. 0gura, K, (1990) Lipid compouRds in lake sediments.  Verh, hitemqt. Verein. Limnol. 24:(in press). -5. 0kino, T. and Members of Routine Observation Group, Lake Suwa  (1990) Water' management and monitoring of Lake Suwa.  .ipn, uTL LimnoL 51:17--23.6. Terashima, S., Inouchi, Y., Nakao, S. and Yonetani, H. (1990)  Geochemistry of 14 elements in bottom sediments from Lake Suwa,  Central Japan. Bull, Geol. Surv. Japan41:147-172.

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CHANGE OF TROPHIC STATUS IN LAKE SUWA DURING 20 YEARS -ELUCIDATION BY RELATIVE ABUNDANCES OF LIPID COMPOUNDS IN SEDIMENTS-

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