Verification of ecosystem alteration risk caused by eutrophication at Lake Baikal

• Project/Area Number: 15H05112
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Environmental dynamic analysis
• Research Institution: The University of Tokyo
• Principal Investigator: Yamamuro Masumi 東京大学, 大学院新領域創成科学研究科, 教授 (80344208)
• Co-Investigator(Kenkyū-buntansha): 田邊 優貴子 国立極地研究所, 研究教育系, 助教 (40550752)
• Research Collaborator: TIMOSHKIN Oleg
• Project Period (FY): 2015-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥15,860,000 (Direct Cost: ¥12,200,000、Indirect Cost: ¥3,660,000); Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2017: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2016: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2015: ¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000)
• Keywords: バイカル湖 / 富栄養化 / 沿岸域 / 大型底生緑藻 / マイクロプラスチック / 下水 / 間隙水 / リン / green tide / Spirogyra / 硫化水素 / 安定同位体比 / 共生海綿 / 底生緑藻 / 地下水 / 窒素安定同位体比 / 緑藻 / ラン藻

Outline of Final Research Achievements

Lake Baikal is an oligotrophic lake and catastrophic change of ecosystem (i.e.bloom of benthic green algae and die off of symbiotic sponges) proceeds recently. This study showed that the change is induced by eutrophication in interstitial water at splash zone originated from sewage. As we found the pile of garbage including various plastics at the coast of Lake Baikal, we conducted sampling of micro plastics. The amount of benthic green algae should decrease if grazer exists. We assume that benthic green algae defend against grazer through producing hydrogen sulfide.

Academic Significance and Societal Importance of the Research Achievements

湖水が貧栄養で維持されているバイカル湖では、共生海綿の衰退や大型底生緑藻の異常繁茂の原因は温暖化であると考えられていた。本研究により原因は未処理の下水の増加による、湖岸間隙水の富栄養化であることが明かになったことから、ロシア政府は、新たに下水処理システムを造設する方針を固めた。大型底生緑藻の異常繁茂は沿岸域や北米の五大湖などでもかねてから問題になっており、原因はリンの増加と考えられている。本研究では補食者が大量死していることから、捕食を免れる機構を備えていることも異常繁茂の原因であることを、世界で初めて指摘した。

Research Products

• [Int'l Joint Research] Limnological Institute, RAS(ロシア連邦)
• [Int'l Joint Research] Limnological Institute SD RAS(ロシア連邦)
• [Journal Article] A review of the Lake Baikal limpets, family Acroloxidae Thiele,1931 (Mollusca: Pulmonata: Hygrophila), based on type specimens, with keys to the genera (2017)
  • Author(s): Alena A. Shirokaya, Tatiana Ya. Sitnikova, Pavel V. Kijashiko, Ihor V, Shydlovskyy, Larisa A. Prozorova and Masumi Yamamuro
  • Journal Title: Archiv fur Molluskenkunde Volume: 146 Issue: 1 Pages: 9-64
  • DOI: 10.1127/arch.moll/146/009-064
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Rapid ecological change in the coastal zone of Lake Baikal (East Siberia): Is the site of the world's greatest freshwater biodiversity in danger? (2016)
  • Author(s): O.A. Timoshkin, D.P. Samsonov, M. Yamamuro 他26名
  • Journal Title: Journal of Great Lakes Research Volume: 42 Issue: 3 Pages: 487-497
  • DOI: 10.1016/j.jglr.2016.02.011
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] Green tide from sea coasts to freshwater lakes. (2018)
  • Author(s): Yamamuro, M.
  • Organizer: International Conference: Freshwater Ecosystems Key Problems
  • Int'l Joint Research / Invited
• [Presentation] ECOCRISIS IN COASTAL ZONE OF LAKE BAIKAL (RUSSIA): AN ARGUMENT FOR COASTAL MONITORING OF LARGE LAKES (2017)
  • Author(s): Timoshkin, O. A.; Tomberg, I. V.; Malnik, V. V.; Yamamuro, M.他11名
  • Organizer: ASLO 2017 Aquatic Science Meeting
  • Place of Presentation: Hawaii (USA)
  • Int'l Joint Research / Invited
• [Presentation] LONG-TERM HYDROCHEMICAL AND MICROBIOLOGICAL SURVEY AT LAKE BAIKAL COASTAL ZONE (2017)
  • Author(s): Malnik, V. V.; Timoshkin, O. A.; Tomberg, I. V.; Sakirko, M. V.; Yamamuro, M
  • Organizer: ASLO 2017 Aquatic Science Meeting
  • Place of Presentation: Hawaii (USA)
  • Int'l Joint Research
• [Remarks] The beaches of the northern top of Lake Baikal
  • URL: http://webpark1489.sakura.ne.jp/docs/profile/video_images/video_10.html
• [Remarks] 地元の市民によるバイカル湖岸の保全活動
  • URL: http://webpark1489.sakura.ne.jp/docs/profile/video_images/video_11.html