Species-specific phytoplankton growth rates via diel DNA synthesis cycles. I. Concept of the method

Carpenter, E. J.; Chang, Jeng Kuei

doi:10.3354/meps043105

Cited by 129 publications

(140 citation statements)

References 20 publications

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“…All of these values are significantly shorter than the 6 h used by Vaulot et al (1995) and Liu et al (1997) for Prochlorococcus in the equatorial Pacific and the subtropical north Pacific, respectively. We suspect that this is partially a result of the higher frequency sampling program used in our study, which allows greater resolution of cell cycle phase durations (McDuff and Chisholm 1982;Carpenter and Chang 1988). Cell cycle duration times shorter than 6 h have also been found for Prochlorococcus in the Arabian Sea (2 to 3 h; Shalapyonok et al 1998).…”

Section: Methodsmentioning

confidence: 87%

“…The latter can be estimated as twice the distance between the peak of cells in the S phase and the peak of cells in the G 2 ϩ M phase (Carpenter and Chang 1988). With this approach, the t values for the site survey, inside the SϩG 2 patch, and the ϩFe bottles were 4.3, 2.3, and 3.0 h, respectively (Table 2).…”

Section: Methodsmentioning

confidence: 98%

“…As a result, the eukaryotic terms G 1 , S, and G 2 ϩ M are often applied to the Prochlorococcus cell cycle for convenience. Moreover, cell division in Prochlorococcus is tightly synchronized to the light:dark cycle (Vaulot et al 1995;Liu et al 1997;Shalapyonok et al 1998), which allows one to estimate the duration of the S and G 2 ϩ M phases of the cell cycle and apply the DNA histogram method of estimating cell division rates (McDuff and Chisholm 1982;Carpenter and Chang 1988;Vaulot et al 1995;Liu et al 1997). In order to determine the duration of S and G 2 ϩ M, DNA fluorescence histograms were modeled and divided into G 1 , S, and G 2 ϩ M using ModFit software (Verity Software House).…”

Section: Methodsmentioning

confidence: 99%

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Iron limits the cell division rate of Prochlorococcus in the eastern equatorial Pacific

Mann

Chisholm

2000

Limnology & Oceanography

120

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Prochlorococcus, a small unicellular cyanobacterium, is an important member of the phytoplankton community in the eastern equatorial Pacific. When these waters were enriched with iron during IronEx II, the chlorophyll per cell and cell size of Prochlorococcus increased, implying that they were iron limited. The extent of this limitation was unclear, however, and the number of Prochlorococcus remained constant. To examine whether cell division rates were stimulated significantly by iron, we used a cell cycle analysis approach to measure them in and out of the Fe-enriched patch and in Fe-enriched bottles. The cell division rate increased from 0.6 to 1.1 d Ϫ1 over 6 d of exposure to the elevated iron concentrations in the patch. Cells incubated in bottles with additional iron had rates of 1.4 d Ϫ1 or two doublings per day. Prochlorococcus mortality rates, measured independently, nearly doubled after the addition of iron. This matched the increase in the cell division rate and maintained a relatively constant population size. Thus the cell division rates of even the smallest phytoplankton in the equatorial Pacific are significantly iron limited, but biomass is constrained by both iron limitation and microzooplankton grazing. The differential response of individual phytoplankton groups to the addition of iron during IronEx II was at least partially a result of differential mortality rates over the time course of the experiment. How the community would respond to sustained fertilization, however, is not obvious.Nitrate and phosphate concentrations are persistently high in the euphotic zone of the equatorial Pacific, and phytoplankton biomass and productivity are lower than expected based on nutrient availability (Cullen 1991;Frost and Franzen 1992). The phytoplankton community is dominated by small picoplankton (Chavez 1989), which have a large surface area to volume ratio and are less likely to be diffusion limited by either nutrients or trace metals than larger cells (Morel et al. 1991a). Measured cell division rates are often 0.5 d Ϫ1 or higher, both for the phytoplankton community as a whole (Barber and Chavez 1991;Chavez et al. 1991;Cullen 1991;Cullen et al. 1992;Landry et al. 1995;Verity et al. 1996;Latasa et al. 1997;Lindley and Barber 1998) and for the small cyanobacterium Prochlorococcus (DuRand 1995;Landry et al. 1995;Vaulot et al. 1995;Binder et al. 1996;Latasa et al. 1997;Liu et al. 1997; Vaulot and Dom-1 Corresponding author (chisholm@mit.edu). AcknowledgementsWe thank the captain and crew of the RV Melville, as well as Kenneth Coale and the Moss Landing IronEx group, for making the experiment possible. We also thank R. Michael Gordon for iron concentration measurements, and Richard Barber, William Cochlan, Michael R. Landry, and Makoto Saito for sharing unpublished data. Comments by J. Cullen, P. Falkowski, and an anonymous reviewer helped improve the manuscript.

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Section: Methodsmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

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Iron limits the cell division rate of Prochlorococcus in the eastern equatorial Pacific

Mann

Chisholm

2000

Limnology & Oceanography

120

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“…Such an approach could improve the accuracy of growth rate estimation and may require less samples for each measuring cycle (McDuff & Chisholm 1982). In additioh, a mathematical derivation indicates that it is possible to estimate the duration of terminal events for a partially synchronized culture without a second independent calibration (Carpenter & Chang 1988). To evaluate the performance of the proposed method, we conducted experiments on a laboratory-cultured dinoflagellate, Heterocapsa tn'quetra, and compared our growth rate estimation with another independent growth rate method.…”

mentioning

confidence: 99%

Species-specific phytoplankton growth rates via diel DNA synthesis cycles. II DNA quantification and model verification in the dino-flagellate Heterocapsa triquetra

Chang¹,

Carpenter²

1988

Mar. Ecol. Prog. Ser.

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The DNA content of individual cells, after being stained by a DNA-specific fluorescent dye, was quantified by a TV camera-based microfluorometry system. Under proper dye concentrations, fluorescence intensity of a stained nucleus was in proportion to the amount of nuclear DNA. Durations of die1 cell cycle phases were estimated with DNA histograms from 2 partially synchronized cultures of the dinoflagellate Heterocapsa tn'quetra. Estimates of growth rate were calculated from phase durations and compared to the growth rates estimated by cell counts. Growth rates calculated by various mathemahcal procedures and sampling intervals were simllar, and the calculated growth rate via DNA synthesis gave a reasonably good estimate of the rate calculated by increase in cell density. This technique is promising in its application to species-specific growth rates in the field.

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“…This phenomenon has been utilized to obtain rough estimates of cell division rates in marine waters (mitotic index method) [McDuff and Chisholm, 1982]. Recent improvements using cell cycle measurements provided much more accurate estimates [Carpenter and Chang, 1988] and revealed the very high synchrony of some oceanic populations [Vaulot et al, 1995].…”

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confidence: 99%

Diel variability of photosynthetic picoplankton in the equatorial Pacific

Vaulot¹,

Marie²

1999

J. Geophys. Res.

205

172

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Abstract. The diel variability in cell abundance, light scatter, and pigment fluorescence of three autotrophic picoplankton groups (Prochlorococcus, Synechococcus, picoeukaryotes) measured by flow cytometry was investigated in surface waters of the equatorial Pacific Ocean (5øS, 150øW) during 5 days with about 1 hour temporal resolution. The diel variability of vertical profiles was examined at the same station on days 2 and 4. Prochlorococcus division rate was also estimated from cell cycle measurements. A more limited data set was obtained at a station located in very oligotrophic waters (16øS, 150øW). All three picoplankton populations exhibited very marked diel variability. Cell division was highly synchronized but not phased identically for all three populations: Synechococcus divided first, followed 2 hours later by Prochlorococcus and 7 hours later by picoeukaryotes. Cells grew in size only once the sun had risen, but growth did continue in the dark for a short period. Growth processes occurred in parallel at the top and the bottom of the mixed layer, inducing uniform profiles for cell abundance and scatter. For chlorophyll fluorescence, in contrast, prokaryotes displayed opposite patterns during the light period between surface (decrease due to very strong quenching) and depth (increase). This created steep vertical gradients during the day that vanished at night because of convective mixing. In the top 25 m, strong light intensities (including UV radiation) had very pronounced detrimental effects on prokaryotes, especially on Prochlorococcus, inducing fluorescence quenching, slowed down growth, and retardation of DNA synthesis.

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Species-specific phytoplankton growth rates via diel DNA synthesis cycles. I. Concept of the method

Cited by 129 publications

References 20 publications

Iron limits the cell division rate of Prochlorococcus in the eastern equatorial Pacific

Iron limits the cell division rate of Prochlorococcus in the eastern equatorial Pacific

Species-specific phytoplankton growth rates via diel DNA synthesis cycles. II DNA quantification and model verification in the dino-flagellate Heterocapsa triquetra

Diel variability of photosynthetic picoplankton in the equatorial Pacific

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