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Flow Cytometry in Biological Oceanography Dr. Frank J. Jochem last revised 04-Jan-2001 
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Flow Cytometry in Biological Oceanography Dr. Frank J. Jochem last revised 04-Jan-2001
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Objectives of Flow Cytometry Work in Marine PlanktologyApplication of flow cytometry was introduced into marine planktology to rapidly and precisely estimate cell numbers of pico- and nanophytoplankton, i.e. algal cells of less than 20 µm in size, within the frame of microbial food web studies in various marine systems. Flow cytometry complemented epifluorescence microscopy in studies on the distribution and composition of pico- and nanophytoplankton populations and allowed higher sampling frequencies along ship transects and during incubation experiments. On board application of flow cytometry allowed distributional studies on prochlorophytes, coccoid cyanobacteria (Synechococcus) and small eukaryotic algae in different oceanic provinces such as the Baltic Sea, the North Atlantic, the Caribbean Sea, the Indian Ocean and in Antarctic waters.In addition to abundance estimates, flow cytometry allows to quantify changes in cellular pigmentation (chlorophyll and phycoerythrin concentrations) of different distinguished phytoplankton sub-populations in response to the light or nutrient regime, either along a depth profile or in incubation experiments. Thus, information on the physiological status or response upon different treatments (changes in light conditions, nutrient additions) can be easily assessed by flow cytometry. In addition to abundance estimates, flow cytometry was used to study ecophysiological aspects of pico- and nanophytoplankton by application of specific fluorescent dyes and/or fluorogenic substrates:
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Lab FacilitiesBecton Dickinson FACSort laser-based (488 nm) cytometer with three channel fluorescence analysis, forward and side scatter, and cell sorting facility. The size resolution of this machine (based on latex particles and in-situ measurements of prochlorophytes of about 0.4 µm in size) is ca. 0.3 µm. Picophytoplankton can be easily detected. Typical measurement volumes range between 20 and 500 µl and cell suspensions of 12,000 to 4,500,000 cells/ml can be processed. The cell sorter allows recovery of sub-populations of interest for further experiments or taxonomic examination. Cell sorting results in a 50 to 100 fold dilution of the sorted cell suspension as compared to the original population; therefore, the cell sorter is equipped with a Becton-Dickinson cell concentrator and a ultra-tangential flow filtration for volumes of 50-150 ml to be concentrated down to 5 ml is available as well. The FACSort has proved convincingly robust and has performed well on several cruises on various research vessels. Since all optical components are standardly mounted on one bench, no problems of alignement or drift in sensitivity was encountered during cruises.A Zeiss Axioskop epifluorescence microscope complements the flow cytometer for visual inspection of plankton samples and staining success. Both instrumentation was funded by German Research Council DFG Jo 192/5-1 and are presently stationed at the Marine Science Institute of The University of Texas at Austin in Port Aransas. |
Research Vessel |
Area |
Time |
Instrument |
| Meteor | North Atlantic | June 1989 |
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| Alkor | Baltic Sea | July 1990 |
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| Alkor | Baltic Sea | August 1991 |
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| Meteor | North Atlantic | May 1992 |
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| Alkor | Baltic Sea | August 1992 |
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| Polarstern | Antarctica | September-November 1992 |
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| Alkor | Baltic Sea | April/May 1993 |
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| Meteor | Mediterranean | June 1993 |
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| Columbus Iselin | Caribbean Sea | September/October 1993 |
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| Gyre | Caribbean Sea | May 1994 |
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| Alkor | Baltic Sea | August 1994 |
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| Alkor | Baltic Sea | October/November 1994 |
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| Meteor | Indian Ocean | May 1995 |
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| Alkor | Baltic Sea | July/August 1995 |
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Links to other working groups applying flow cytometry in aquatic sciences and related sites:Cytometry Pages
Other Marine Sites |