31 Oct 2019

Seminar Title: How the bSi increasing in diatoms influences the grazing of copepods: perspective from the composition, nanostructure, and mechanic properties of the cell wall

Speaker: Mr XU Huo (Supervisor: Prof. LIU Hongbin)

Date: 31 October, 2019 (Thursday)
Time: 5:00 pm – 5:50 pm
Venue: Room 4502 (lift no. 25-26), HKUST

Abstract:
There is a prevalent hypothesis that an increase of silicon in diatoms contributes to protect grazing against copepods. However, this is not always the case in lab experiments, which makes us doubt whether the increase of the bSi content will definitely enhance the stability of diatom structure and affect copepods. Through a designed copepods feeding experiments, we firstly found that copepods showed distinct clearance rate and ingestion rate when preyed between the high-bSi Thalassiosira weissflogii and high-bSi Amphora coffeneformis. We then focused on the cell surface structure and chemical composition analysis by Atomic Force Microscope (AFM) and X-ray photoelectron spectroscopy (XPS), and proposed a new technical method for diatom morphology and cell mechanics analysis, which is of great significance to explain how the surface structure of diatom cells affects predators under different conditions.

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