Prochlorococcus and Synechococcus cell counts in dilution experiment treatments from samples collected on RV Cape Hatteras cruises CH0409 and CH0510 in 2009 and 2010.

Website: https://www.bco-dmo.org/dataset/716979
Data Type: Cruise Results
Version: 1
Version Date: 2017-10-12

Project
» Top-Down Regulation of Picophytoplankton in the Sargasso Sea: Application of a Reciprocal Transplant / Dilution Approach (Picophytoplankton_Regulation)
ContributorsAffiliationRole
Binder, BrianUniversity of Georgia (UGA)Principal Investigator
Ake, HannahWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Prochlorococcus and Synechococcus cell counts in dilution experiment treatments from samples collected on RV Cape Hatteras cruises CH0409 and CH0510 in 2009 and 2010.

Table of Contents

Coverage

Spatial Extent: N:30.9082 E:-71.8634 S:30.1464 W:-72.8769
Temporal Extent: 2009 - 2010

Dataset Description

Prochlorococcus and Synechococcus cell counts in dilution experiment treatments.


Methods & Sampling

Dilution Experiments: For an overview of the purpose and interpretation of dilution experiments see Landry (1993) and Worden & Binder (2003). Seawater samples were taken with Go-Flo bottles suspended on non-metallic cable. A portion of this water was gravity-filtered through 0.2 um pore-size capsule filters (Whatman Polycap 36 TC), and appropriate volumes of filtered and unfiltered seawater were added to 500 ml polycarbonate bottles to achieve the indicated dilutions. Time-0 (T0) samples were removed from each bottle and preserved for later flow cytometric analysis as described below. Incubation bottles were then distributed to nylon mesh bags and resuspended in the water column at the depths indicated. After 24 hours, the bottles were recovered and sampled for time-final (TF) counts. All sampling gear, filters, and incubation bottles were acid-washed per Fitzwater et al. (1982). The dates, times, and locations of the experiments were as follows:
 
Cruise      Exper    Date (UTC)    T0 (UTC)     E Long     N Lat
CH0409    X1         26-May-09     17:58:30     -71.998    30.171
CH0409    X2         29-May-09     13:28:09     -72.002    30.173
CH0510    X2         27-May-10     13:33:30     -72.683    30.699
 
Flow Cytometric Cell Counts: Samples were fixed with freshly titrated paraformaldehyde (pH 7.4–8.1, 0.1% final concentration), held in the dark for 10 min, frozen in liquid nitrogen, and stored in a ‑80 deg C freezer (CH0409 samples) or in liquid nitrogen (CH0510 samples) until analysis. Preserved samples were analyzed by flow cytometry on a modified Coulter-EPICS 753 flow cytometer (Binder et al. 1996). Samples were chosen in random order and defrosted in a 30 deg C water bath (just long enough to melt, ~5 min). Prior to analysis, polystyrene fluorescent beads (Flow Check® 0.494 um “BB”; Polysicences Inc., Washington, PA, USA), were added to each sample, and used to normalize cellular light scatter and fluorescence. Samples were typically run at an infusion rate of 20 uL min-1 for 1 to 20 min, depending on cell abundance within the sample. A minimum of 1,000 Prochlorococcus cells were analyzed, except for samples in which low cell concentrations made this impractical. Final cell concentrations tabulated here were calculated from 1-7 replicate counts (Count.n).

Data Processing Description

BCO-DMO Data Processing Notes:

- removed rows that had all blank cells
- replaced all decimal points in column headers with underscores
- removed units from column names


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Data Files

File
dilutionexpercellcounts.csv
(Comma Separated Values (.csv), 10.78 KB)
MD5:97750ea595800c88d60c78a6775d65be
Primary data file for dataset ID 716979

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Related Publications

Binder, B.J., Chisholm, S.W., Olson, R.J., Frankel, S.L., Worden, A.Z. (1996). Dynamics of picophytoplankton, ultraphytoplankton, and bacteria in the central equatorial Pacific. Deep-Sea Res. II 43:907-931.
Methods
Fitzwater, S. E., Knauer, G. A., & Martin, J. H. (1982). Metal contamination and its effect on primary production measurements1. Limnology and Oceanography, 27(3), 544–551. doi:10.4319/lo.1982.27.3.0544
Methods
Landry, M.R. (1993). Estimating rates of growth and grazing mortality of phytoplankton by the dilution method In P.F. Kemp, B.F. Sherr, E.B. Sherr, J.J. Cole (eds) Handbook of methods in aquatic microbial ecology (pp. 715–722). Boca Raton, FL: Lewis Publishers.
Methods
Worden, A., & Binder, B. (2003). Application of dilution experiments for measuring growth and mortality rates among Prochlorococcus and Synechococcus populations in oligotrophic environments. Aquatic Microbial Ecology, 30, 159–174. doi:10.3354/ame030159
Methods

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Parameters

ParameterDescriptionUnits
CruiseR/V Cape Hatteras Cruise Designation unitless
ExperExperiment Designation unitless
BottleUnique incubation bottle identifier unitless
Depth_SampleDepth of source water meters
Depth_IncubateDepth of incubation meters
DilutionFraction of unfiltered seawater in bottle number
TimeSampling time; timepoints unitless
ProProchlorococcus Cell Concentration cells per milliliter
SynSynechococcus Cell Concentration cells per milliliter
CountNumber of counts underlying cell concentrations number


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Instruments

Dataset-specific Instrument Name
Go-flo bottle
Generic Instrument Name
GO-FLO Bottle
Dataset-specific Description
Used to take seawater samples
Generic Instrument Description
GO-FLO bottle cast used to collect water samples for pigment, nutrient, plankton, etc. The GO-FLO sampling bottle is specially designed to avoid sample contamination at the surface, internal spring contamination, loss of sample on deck (internal seals), and exchange of water from different depths.

Dataset-specific Instrument Name
Coulter-EPICS 753 flow cytometer
Generic Instrument Name
Flow Cytometer
Dataset-specific Description
Used to analyze preserved samples
Generic Instrument Description
Flow cytometers (FC or FCM) are automated instruments that quantitate properties of single cells, one cell at a time. They can measure cell size, cell granularity, the amounts of cell components such as total DNA, newly synthesized DNA, gene expression as the amount messenger RNA for a particular gene, amounts of specific surface receptors, amounts of intracellular proteins, or transient signalling events in living cells. (from: http://www.bio.umass.edu/micro/immunology/facs542/facswhat.htm)


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Deployments

CH0409

Website
https://www.bco-dmo.org/deployment/716831
Platform
R/V Cape Hatteras
Report
https://ezid.cdlib.org/id/doi:10.7284/902620
Start Date
2009-05-20
End Date
2009-06-02
Description
Project: Top-Down Regulation of Picophytoplankton in the Sargasso Sea: Development and Application of a Reciprocal Transplant/Dilution Approach

CH0510

Website
https://www.bco-dmo.org/deployment/716833
Platform
R/V Cape Hatteras
Report
https://ezid.cdlib.org/id/doi:10.7284/901958
Start Date
2010-05-20
End Date
2010-06-02
Description
Project: Top-Down Regulation of Picophytoplankton in the Sargasso Sea: Development and Application of a Reciprocal Transplant/Dilution Approach


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Project Information

Top-Down Regulation of Picophytoplankton in the Sargasso Sea: Application of a Reciprocal Transplant / Dilution Approach (Picophytoplankton_Regulation)

Coverage: Western Sargasso Sea (vicinity of 30 N 72 W)


The intellectual merit of the research is to extend our understanding of the biology and ecology of marine picophytoplankton, a group of microbes that are responsible for a large proportion of the total photosynthetic carbon fixation that occurs in the world's oceans. The importance of picophytoplankton as the dominant primary producers in open-ocean ecosystems is well-established. However, the factors that regulate the distribution and abundance of these populations remain poorly understood. The investigators will explore the dynamics of top-down (grazer-mediated) regulation of picophytoplankton populations in a specific context: the maintenance of summertime subsurface maxima in the pico-cyanobacterium Prochlorococcus (but not Synechococcus) in the Sargasso Sea. This phenomenon represents a relatively simple and predictable model system within which to test hypotheses about the regulation of oceanic picophytoplankton in general.
Recent results suggest that despite their abundance, Prochlorococcus in the subsurface maxi-mum are growing (and being grazed) rather slowly, as compared to the smaller population at the surface. In order to understand the factors responsible for this apparent paradox, this project will use a combination of field and laboratory studies to characterize and compare the interactions between Prochorococcus and its protozoan grazers at these two contrasting depths, and in relation to Synechococcus, which forms no such sub-surface maximum.
The broader impacts include training for graduate and undergraduate students. In addition, given the significance of picophytoplankton as primary producers at the base of oceanic microbial food webs, the results of this project should inform efforts to describe and model the broader oceanic ecosystem, and ultimately to understand its role in the global carbon cycle.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)
OCE-0751672

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