Autofluorescence imaging system to discriminate and quantify the distribution of benthic cyanobacteria and diatoms
Carreira, C; Staal, M.; Middelboe, M.; Brussaard, C.P.D. (2015). Autofluorescence imaging system to discriminate and quantify the distribution of benthic cyanobacteria and diatoms. Limnol. Oceanogr., Methods 13(4): 169–177. dx.doi.org/10.1002/lom3.10016
In: Limnology and Oceanography: Methods. American Society of Limnology and Oceanography: Waco, Tex.. ISSN 1541-5856; e-ISSN 1541-5856, more
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| Authors | | Top |
- Carreira, C, more
- Staal, M.
- Middelboe, M., more
- Brussaard, C.P.D., more
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| Abstract |
Observation of benthic photoautotrophs on sediment surfaces shows a single algal layer without distinctionbetween photosynthetic groups. Until now it has not been possible to distinguish between benthic photosyntheticmicroorganisms, i.e. cyanobacteria and diatoms, at lm to mm scales using a single nondisruptivesystem. Chlorophyll autofluorescence can be used to distinguish different photoautotrophic groups if the correctexcitation light is applied. Using this principle, a nonintrusive technique was developed to study the spatialdistribution of benthic cyanobacteria and diatoms. By means of a charge coupled device camera, diatomsand cyanobacteria could be identified by blue light (470 nm) excitation and amber light (600 nm) excitation,respectively. By this approach, diatom or cyanobacterial dominance could be easily distinguished using theblue over amber ratio. We applied this method successfully to (mixed) laboratory cultures as well as naturalphotosynthetic microbial mats. Cultures of the diatom Nitzschia capitellata and the cyanobacterium Geitlerinemasp. showed close correlation between autofluorescence and cell abundance. This simple and cheapimaging system allows fast observations of the fine-scale (lm–mm) spatial heterogeneities of live benthicmicrobial photoautotrophs both in culture and natural photosynthetic biofilms structure (e.g., microphytobenthosand photosynthetic microbial mats). |
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