A single probe fibre optic fluorosensor for marine and freshwater measurements of phytoplankton populations

McStay, Daniel; Milne, Robert G.; Wright, G. G.; Dunn, J.

doi:10.1080/01431169508954454

Cited by 1 publication

(1 citation statement)

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“…The detection limit for chlorophyll a in diatoms of 0.03 g liter Ϫ1 is lower than those of most of the in vivo fluorescence methods reported in the literature. Recently, a sensitive optical fiber fluorosensor for phytoplankton biomass determinations that is capable of resolving in vivo chlorophyll concentrations of 0.1 g liter Ϫ1 has been described (15). These authors used a 250-W xenon lamp as the light source.…”

Section: Discussionmentioning

confidence: 99%

A new in vivo fluorimetric technique to measure growth of adhering phototrophic microorganisms

Karsten¹,

Klimant²,

Holst³

1996

Appl Environ Microbiol

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We developed a noninvasive rapid fluorimetric method for the investigation of growth of adhering (benthic) phototrophic microorganisms. The technique is based on the sensitive detection of the in vivo fluorescence of chlorophylls chlorophyll a and bacteriochlorophyll a and monitors increases in signal over time as an indicator for growth. The growth fluorimeter uses modulated excitation light of blue-light-emitting diodes and a photodiode as the detector. The light-emitting diodes are mounted geometrically in an aluminum housing for efficient and uniform illumination of the bottoms of the growth containers. The fluorimeter was characterized with respect to detection limit and dynamic range. This system is capable of resolving in vivo chlorophyll a concentrations of 0.5 g liter ؊1 in cyanobacteria and 0.03 g liter ؊1 in diatoms as well as in vivo bacteriochlorophyll a concentrations in phototrophic bacteria of 0.3 g liter ؊1 , which points to an extremely high sensitivity compared with that of similar available techniques. Thus, the new fluorimeter allows the determination of growth at extremely low cell densities. The instrument was used successfully to measure the growth of several adhering isolates of the filamentous cyanobacterium Microcoleus chthonoplastes from benthic microbial mats in seawater of different salinities. The data obtained demonstrate broad growth responses for all strains, which thus can be characterized as euryhaline organisms.

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Section: Discussionmentioning

confidence: 99%