Trophic interactions between picophytoplankton and micro- and nanozooplankton in the western Arabian Sea during the NE monsoon 1993

Reckermann, Marcus; Veldhuis, Mjw

doi:10.3354/ame012263

Cited by 135 publications

(88 citation statements)

References 40 publications

(55 reference statements)

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“…Lastly, cell cycle analysis and diel variations in abundances and sizes of PRO indicated that growth and grazing mortality rates increased in the patch to at least 1.0 d -1 . Although PRO were initially believed to be constrained by synchronous cell division to growth rates of no more than 0.7 d -1 in the equatorial Pacific (Vaulot et al 1995), these higher rates under favorable environmental conditions are consistent with recent results from the Arabian Sea (Reckermann & Veldhuis 1997.…”

Section: Dynamics Of the Ironex II Bloomsupporting

confidence: 78%

Biological response to iron fertilization in the eastern equatorial Pacific (IronEx II). III. Dynamics of phytoplankton growth and microzooplankton grazing

Landry¹,

Constantinou²,

Latasa³

et al. 2000

Mar. Ecol. Prog. Ser.

198

143

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Section: Dynamics Of the Ironex II Bloomsupporting

confidence: 78%

Biological response to iron fertilization in the eastern equatorial Pacific (IronEx II). III. Dynamics of phytoplankton growth and microzooplankton grazing

Landry¹,

Constantinou²,

Latasa³

et al. 2000

Mar. Ecol. Prog. Ser.

198

143

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“…This would suggest that the grazers of phytoplankton in the large size category did occur in our incubation bottles; otherwise the grazing impact of the large particles would be small (growth rate of large size category would largely exceed grazing mortality). Previous studies using size-fractionated dilution experiments also F. H. Chang et al: Scaling of growth rate and mortality 5277 support our findings, as their grazing mortality estimates from the < 20 µm and < 200 µm fractions do not significantly differ (Lessard and Murrell, 1998;Reckermann and Veldhuis, 1997). However, given relatively scarce studies on sizespecific growth rate and grazing mortality, it is not clear how the technical issues of such bottle incubation could affect the size-specific level investigation.…”

Section: Difficulties In Testing the Mte In Natural Phytoplankton Asssupporting

confidence: 53%

“…This new approach overcomes the deficiency in traditional sizefractionated chlorophyll measurements (Calbet et al, 2001Calbet, 2008;Lessard and Murrell, 1998;Reckermann and Veldhuis, 1997), which cannot provide satisfactory size resolution. Combining the detailed size information acquired from the FlowCAM and dilution technique, we were able to measure the size-specific growth and mortality rate of microphytoplankton with high resolution ranging from 10 to 300 µm.…”

Section: Flowcam Analysismentioning

confidence: 99%

Scaling of growth rate and mortality with size and its consequence on size spectra of natural microphytoplankton assemblages in the East China Sea

et al. 2013

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Allometric scaling of body size versus growth rate and mortality has been suggested to be a universal macroecological pattern, as described by the metabolic theory of ecology (MTE). However, whether such scaling generally holds in natural assemblages remains debated. Here, we test the hypothesis that the size-specific growth rate and grazing mortality scale with the body size with an exponent of −1/4 after temperature correction, as MTE predicts. To do so, we couple a dilution experiment with the FlowCAM imaging system to obtain size-specific growth rates and grazing mortality of natural microphytoplankton assemblages in the East China Sea. This novel approach allows us to achieve highly resolved size-specific measurements that would be very difficult to obtain in traditional size-fractionated measurements using filters. Our results do not support the MTE prediction. On average, the size-specific growth rates and grazing mortality scale almost isometrically with body size (with scaling exponent ∼0.1). However, this finding contains high uncertainty, as the size-scaling exponent varies substantially among assemblages. The fact that size-scaling exponent varies among assemblages prompts us to further investigate how the variation of size-specific growth rate and grazing mortality can interact to determine the microphytoplankton size structure, described by normalized biomass size spectrum (NBSS), among assemblages. We test whether the variation of microphytoplankton NBSS slopes is determined by (1) differential grazing mortality of small versus large individuals, (2) differential growth rate of small versus large individuals, or (3) combinations of these scenarios. Our results indicate that the ratio of the grazing mortality of the large size category to that of the small size category best explains the variation of NBSS slopes across environments, suggesting that higher grazing mortality of large microphytoplankton may release the small phytoplankton from grazing, which in turn leads to a steeper NBSS slope. This study contributes to understanding the relative importance of bottom-up versus top-down control in shaping microphytoplankton size structure

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“…Populations in the ϩFe bottles had cell division rates of 1.4 d Ϫ1 , which is equal to two doublings per day and significantly higher than any growth rate previously recorded for Prochlorococcus in the equatorial Pacific. Division rates greater than one division per day that are either supported by a second round of division seen in the DNA histograms or calculated by the dilution technique (Landry et al 1995) have only been reported for the highly productive Arabian Sea (Reckermann and Veldhuis 1997;Liu et al 1998;Shalapyonok et al 1998). These results indicate that the maximum cell division rate of Prochlorococcus in the equatorial Pacific if iron is abundant is 1.4 d Ϫ1 , significantly higher than the cell division rates found in situ in this and other studies (DuRand 1995;Vaulot et al 1995;Binder et al 1996;Latasa et al 1997;Liu et al 1997).…”

Section: Resultsmentioning

confidence: 99%

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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Trophic interactions between picophytoplankton and micro- and nanozooplankton in the western Arabian Sea during the NE monsoon 1993

Cited by 135 publications

References 40 publications

Biological response to iron fertilization in the eastern equatorial Pacific (IronEx II). III. Dynamics of phytoplankton growth and microzooplankton grazing

Biological response to iron fertilization in the eastern equatorial Pacific (IronEx II). III. Dynamics of phytoplankton growth and microzooplankton grazing

Scaling of growth rate and mortality with size and its consequence on size spectra of natural microphytoplankton assemblages in the East China Sea

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

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