Roles of mixotrpohs in material cycling of the ocean

2014 Fiscal Year Final Research Report

• Project/Area Number: 25850129
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Aquatic bioproduction science
• Research Institution: The University of Tokyo
• Principal Investigator: SATO Mitsuhide 東京大学, 農学生命科学研究科, 助教 (60466810)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 混合栄養生物 / フローサイトメトリー / 栄養塩 / 質量分析 / 物質循環

Outline of Final Research Achievements

Mixotorphy, which is a combination of photosynthesis and phagotrophy, is a universal trait among marine phytoplankton. In the present study, mixotrophs in the open ocean were quantified using the two different methods, tradtional fluorescently labelled bacteria method and a combination of flow cytometry and an acidotorpic fluorescent probe. The results using the two methods were well correlated with each other, showing that the latter mehods is ronbust in quantifying mixtrophs in natural environments. The relative importance of mixotrophs was higher in the subtropical waters, which contain scarce bioavailable nutrients. This suggests that phagotrophy is an effective strategy for nutrient acquisition. I also examined the optimum conditions for secondary ion mass spectrometry of the samples from the experiments where natural plankton communities were fed with isotope-labelled prey, in order to quantify mixotroph abundance and grazing.

Free Research Field

生物海洋学