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    Chlorophyll measurements from the MesoHux mesocosm experiment held in May 2017
    
  
  
    
    

Chlorophyll measurements from the MesoHux mesocosm experiment held in May 2017

Website: https://www.bco-dmo.org/dataset/748471
Data Type: experimental
Version: 1
Version Date: 2018-09-14

Project
» Quantifying competing loss rates of viral lysis and microzooplankton grazing on Emiliania huxleyi mortality (E huxleyi Mortality)
ContributorsAffiliationRole
Johnson, Matthew D.Woods Hole Oceanographic Institution (WHOI)Principal Investigator
Bidle, Kay DRutgers UniversityCo-Principal Investigator
Harvey, ElizabethUniversity of Georgia (UGA)Co-Principal Investigator
Biddle, MathewWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Chlorophyll measurements from the MesoHux mesocosm experiment held in May 2017


Coverage

Temporal Extent: 2017-05-12 - 2017-05-30

Dataset Description

Water samples for chlorophyll extraction were collected from the mesocosms via a 5 L Niskin. Chlorophyll samples were filtered in triplicate through a 25mm Glass Fiber Filter (GFF), and immediately extracted in 6 mL of ethanol for 12-18 hours in the dark at room temperature. After extraction, filters were removed from the sample, and the fluorescence of the sample was read on a Turner AU10. The sample was then acidified with 1 drop of 10% HCL and re-read on the same instrument. The fluorometer was calibrated prior to using with a chlorophyll standard purchased from Sigma.

Mesocosm treatments are as follows:
P-limited: N:P added in a 60:1 ratio during the first 3 days of the experiment, no shading
Redfield: N:P added in a 16:1 ratio during the first 3 days of the experiment, no shading
Shaded: N:P added in a 16:1 ratio during the first 3 days of the experiment, top shaded of the mesocosm added on May 20, 2017
Ambient: no nutrients added, no shading
Samples were taken from either 1m, 5m, or from sediment from settling cones. Samples were noted in the Sample Depth (m) column.


Processing Description

BCO-DMO Processing Notes:

  • converted date from Mon, DD, YYYY to YYYY-MM-DD
  • addead header "notes" for 4th column
  • removed units and special characters from header
  • aggregated chlorophyll and sizefracchla files

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Parameters

ParameterDescriptionUnits
filenamename of the file unitless
Datedate of sample in YYYY-MM-DD format unitless
Sampleidentifier for the sample unitless
Stationstation identifier unitless
notesadditional notes unitless
Sample_Depthdepth of the sample meters (m)
Volume_Filteredvolume filtered mililiters (mL)
Extract_Volumevolume extracted mililiters (mL)
Dilution_Factordiltion factor unitless
F_oinitial fluorescence reading RFU
F_o_minus_blankinitial fluorescence reading RFU
F_afluorescence after acidification RFU
F_a_minus_blankfluorescence after acidification RFU
Total_chlorophylltotal chlorophyll micrograms per liter (ug/L)
Chl_achlorophyll a micrograms per liter (ug/L)
PheoPheo micrograms per liter (ug/L)


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Instruments

Dataset-specific Instrument Name
Turner AU10 fluorometer
Generic Instrument Name
Turner Designs Fluorometer -10-AU
Dataset-specific Description
After extraction, filters were removed from the sample, and the fluorescence of the sample was read on a Turner AU10.
Generic Instrument Description
The Turner Designs 10-AU Field Fluorometer is used to measure Chlorophyll fluorescence. The 10AU Fluorometer can be set up for continuous-flow monitoring or discrete sample analyses. A variety of compounds can be measured using application-specific optical filters available from the manufacturer. (read more from Turner Designs, turnerdesigns.com, Sunnyvale, CA, USA)


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Deployments

MesoHux_2017

Website
Platform
National Mesocosm Centre
Start Date
2017-05-01
End Date
2017-05-31
Description
Mesocosm experiments on bacteria and viruses.


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Project Information

Quantifying competing loss rates of viral lysis and microzooplankton grazing on Emiliania huxleyi mortality (E huxleyi Mortality)


Description from NSF award abstract: Processes that either promote growth or cause mortality drive the abundance of all organisms. For microbes such as phytoplankton, that have a lifespan measured in hours to days, small changes in these processes can have significant impacts. Phytoplankton are the central currency in the flow of material and nutrients throughout the marine environment. Even small shifts in their growth and mortality rates will have large-scale implications for ecosystem structure and biogeochemical cycling. While factors that influence growth are often examined, less is known regarding the regulation of phytoplankton mortality. This project will focus on quantifying competing modes of mortality on the bloom-forming coccolithophore, Emiliania huxleyi, a globally important phytoplankton species that contributes significantly to ocean carbon and sulfur cycles. Mortality due to grazing by single-celled microzooplankton is the largest contributor to phytoplankton loss in the marine environment. However, E. huxleyi also has a well-characterized relationship with a virus that can result in mass mortality. Therefore, E. huxleyi serves as a good model organism for examining how mortality is partitioned between grazing by microzooplankton predators and lysis due to viral infection. Quantifying these mortality mechanisms will help to inform mathematical models for the accurate prediction of shifts in E. huxleyi population dynamics and ultimately, primary production and biogeochemical cycling. This work will involve collaboration with a high school science teacher in a school system with a large proportion of students from underrepresented groups, in the creation and implementation of short film clips that depict important ecological interactions. These film clips will then be incorporated into laboratory activities to communicate these concepts to students. Further, undergraduate students from underrepresented groups will be trained at both Woods Hole Oceanographic Institute and Rutgers University, to perform laboratory research on mortality processes on phytoplankton. This research will also provide training and career development for a postdoctoral scientist. Mortality mechanisms in phytoplankton have generally been studied independent from one another, however in nature, these processes act concurrently. The relative proportion that microzooplankton grazing and viral lysis contribute to overall E. huxleyi loss and how they may interact to shape bloom dynamics is largely unknown. Understanding the relative importance of these processes, as well as their interaction, is critical due to their contrasting influence on the structure and function of marine food webs and biogeochemical cycles. While grazing tends to channel phytoplankton biomass to higher trophic levels, viral lysis stimulates microbial loop activity and vertical particle export flux. This research will determine the effect of one mortality process on the other, as well as their net effect on E. huxleyi population dynamics and export in both laboratory and field mesocosm experiments. This integrated approach will provide a unique mechanistic perspective of multi-trophic microbial interactions, thereby increasing the potential for accurate predictions of E. huxleyi population dynamics and biogeochemical cycling. The outcomes of this research have the potential to yield broadly applicable insights into how microbial interactions can drive ecological and biogeochemical dynamics in the marine environment. This project is funded by an NSF Collaborative Research award.


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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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This document is created by info v 4.1f 5 Oct 2018 from the content of the BCO-DMO metadata database.    2020-02-17  16:19:44