Biodiv Sci ›› 2016, Vol. 24 ›› Issue (7): 847-854.DOI: 10.17520/biods.2015320

Special Issue: 全球气候变化下的海洋生物多样性专辑

• Orginal Article • Previous Articles     Next Articles

Observing the morphological features of Emiliania huxleyi coccoliths using atomic force microscopy

Yu Wang1, Huiyong Zhang2, Peng Xiang1, Youyin Ye1, Gengming Lin1, Qingliang Yang1, Mao Lin1,*()   

  1. 1 Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian 361005
    2 Zealquest Open Laboratory of Zealquest Technology Limited Company, Shanghai 200333
  • Received:2015-11-16 Accepted:2016-04-15 Online:2016-07-20 Published:2016-08-04
  • Contact: Lin Mao

Abstract:

Coccolithophores are important components of the phytoplankton community that play a unique role in the global ocean biogeochemical cycle though carbon fixation and calcium carbonate production. In addition, coccolithophores are good indicators of climate change as they have indicative organic and inorganic remnants in sediments. Emiliania huxleyi is the most typical representative of coccolithophores. Classification of coccolithophores is mainly based on coccoliths, which have very fine and complex structures and are easily destroyed during the sample collection process. It becomes a technical problem to identify coccolithophores. In this study, atomic force microscopy (AFM) was employed to observe coccoliths of Emiliania huxleyi with the purpose of establishing an AFM sample preparation method for coccolithophores. Centrifugation was found to be an appropriate method to deal with the AFM samples compared with filtration. An optimized protocol was established: cells are centrifuged at 3,000-4,000 rpm, 20℃, over 5 minutes, a precipitate is suspended in 0.05 M NH4HCO3 solution, and then a droplet of solution containing suspended coccoliths is pipetted onto a glass attached to the sample holder. High resolution images had been captured under the contact mode of AFM in air conditioning with a scan range of 50 µm and frequency of 1 Hz. The method is applicable to analyze the morphological features of coccoliths under various environmental parameters or gradients in the laboratory and is also suitable for coccolithophore bloom detection.

Key words: Emiliania huxleyi, coccolith, morphological feature, atomic force microscopy (AFM), height image, deflection image