Abstract

<b>Linear discriminant analysis (LDA) of single-cell fluorescence excitation spectra (λ<sub>em</sub> = 680 nm) for five species of marine phytoplankton was used to determine whether intra-species variation among single cells precluded discrimination among species. Single-cell spectra were recorded in an optical trap with a custom-built spectral fluorometer. For nitrogen (N)-replete cells, separation of all five species (<i> Emiliania huxleyi</i>, a coccolithophore,</b> <b><i>Thalassiosira pseudonana</i>, a diatom,</b> <b><i>Dunaliella tertiolecta</i>, a chlorophyte,</b> <b><i>Amphidinium carterae</i>, a dinoflagellate, and</b> <b><i>Rhodomonas salina</i>, a cryptophyte) was possible using only a portion of the excitation spectra (570-610 nm). This wavelength region gave perfect classification of species with a minimum Fisher ratio of 62. For four species (<i> E. huxleyi</i>,</b> <b><i>T. pseudonana</i>,</b> <b><i>D. tertiolecta,</i></b> <b>and</b> <b><i>A. carterae</i>), variations in fluorescence excitation spectra as cells were starved of N did not impact the classification process adversely within the chosen spectral window.</b> <b><i>R. salina</i></b> <b>cells grown with and without N showed significant differences in their fluorescence excitation spectra but could still be classified if a different spectral window (490-570 nm) was used. Overall, we conclude that intra-species variation among single-cell fluorescence excitation spectra does not preclude discrimination among species.</b>

PDF Article

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription