The relationship between dissolved organic matter cycling and bacterioplankton in freshwater environments

• Project/Area Number: 23710023
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Environmental dynamic analysis
• Research Institution: Center for Environmental Science in Saitama (2012); National Institute for Environmental Studies (2011)
• Principal Investigator: WATANABE Keiji 埼玉県環境科学国際センター, 水環境担当, 主任 (50575230)
• Project Period (FY): 2011 – 2013
• Project Status: Completed (Fiscal Year 2013)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2012: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000); Fiscal Year 2011: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
• Keywords: 微生物ループ / 物質循環 / 溶存有機物 / 浮遊細菌 / 湖沼環境

Research Abstract

We have succeeded to the isolation of many of dominant but unculturable freshwater bacterioplankton clusters/subclusters from the freshwater lakes and a river. These isolates were strongly dependent on the carboxylic acids as carbon source. Freshwater bacterioplankton subclusters (PnecC and PnecD) have shown the niche separation by the difference of main source of carboxylic acids in the field (photodegradation of humic substances or primary production). In addition, the production of chromophoric dissolved organic matter which has terrestrial humic-like fluorescence by part of freshwater clusters/subclusters was observed in the cultivation experiments. The contribution of freshwater bacterioplankton to carbon cycle has been partly cleared due to the cultivation-based approach using pure strains.

Research Products

• [Journal Article] Ecological niche separation in the Polynucleobacter subclusters linked to quality of dissolved organic matter: a demonstration using a high sensitivity cultivation-based approach (2012)
  • Author(s): Watanabe K., Komatsu N., Kitamura T., Ishii Y., Park H-D., Miyata R., Noda N., Sekiguchi Y., Satou T., Watanabe M., Yamamura S., Imai A., Hayashi S
  • Journal Title: Environmental Microbiolog Volume: Vol. 14, No.9 Issue: 9 Pages: 2511-2525
  • DOI: 10.1111/j.1462-2920.2012.02815.x
  • Peer Reviewed
• [Presentation] Ecological niche separation in the Polynucleobacter subclusters linked to quality of dissolved organic matter (2012)
  • Author(s): Watanabe K
  • Organizer: Aquatic Science Meeting
  • Place of Presentation: Lake Biwa, Shiga, Japan
  • Year and Date: 2012-07-10
• [Presentation] Ecological niche separation in the Polynucleobacter subclusters linked to quality of dissolved organic matter (2012)
  • Author(s): Keiji Watanabe
  • Organizer: ASLO Aquatic Science Meeting
  • Place of Presentation: 琵琶湖ホール（滋賀県）
• [Presentation] 湖沼で優占する浮遊細菌群の生理生態的特徴 (2011)
  • Author(s): 渡邊圭司
  • Organizer: 日本微生物生態学会
  • Place of Presentation: 京都大学北部キャンパス農学部総合館
  • Year and Date: 2011-10-08
• [Presentation] 湖沼における主要浮遊細菌群の生態 (2011)
  • Author(s): 渡邊圭司
  • Organizer: 日本陸水学会
  • Place of Presentation: 島根大学松江キャンパス
  • Year and Date: 2011-09-23
• [Presentation] 湖沼における主要浮遊細菌群の生態と湖内炭素循環への寄与 (2011)
  • Author(s): 渡邊圭司、佐藤貴之、渡邊未来、山村茂樹、今井章雄、林誠二、北村立実、小松伸行、石井裕一
  • Organizer: 日本陸水学会
  • Place of Presentation: 島根大学松江キャンパス