|Olson, Brady M.||Western Washington University (WWU)||Principal Investigator|
|Love, Brooke||Western Washington University (WWU)||Co-Principal Investigator|
|Strom, Suzanne||Western Washington University (WWU)||Co-Principal Investigator|
|Still, Kelly Ann||Western Washington University (WWU)||Student|
|Copley, Nancy||Woods Hole Oceanographic Institution (WHOI BCO-DMO)||BCO-DMO Data Manager|
Kendall, K., Marine Microzooplankton are Indirectly Affected by Ocean Acidification Through Direct Effects on Their Phytoplankton Prey. (Masters Thesis) Western Washington University. http://cedar.wwu.edu/wwuet/448/
The phytoplankton Rhodomonas sp. CCMP 755 was grown semi-continuously in atmosphere controlled chambers at three different CO2 treatment concentrations; Ambient (400ppmv), Moderate (750ppmv), and High (1000ppmv). Cultures were diluted daily starting day 4 with pre-equilibrated media containing f/50 nutrients. Some of the culture removed was used to evaluate chemical parameters.
pCO2 Rhodomonas: Samples for total alkalinity were taken on growth days 1, 3, 5, 7, 11, 12, 13 and 17 and preserved with HgCl2 and stored at 4° until analysis. Alkalinity was measured by gran titration using a Titrando 888, and 0.1 N HCl titrant, in a temperature controlled titration vessel. DIC samples were filtered through a 0.2 µm nylon syringe filter on the morning of the experimental day, then stored in airtight vials at 4°C until analysis within 60 days using an Apollo SciTech DIC Analyzer AS-C3 which incorporates the LI-7000 CO2/H2O Analyzer. Other parameters were calculated with CO2sys.
pCO2 Rhodomonas and long-term grazing by Coxliella: Samples for total alkalinity of pre-equilibrated media were taken on growth day 11 and from the Rhodomonas plus Coxliella grazing treatments on day16 and preserved with HgCl2 and stored at 4° until analysis. Alkalinity was measured by gran titration using a Titrando 888, and 0.1 N HCl titrant, in a temperature controlled titration vessel. DIC samples from the long-term grazing experiment were filtered through a 0.2 µm nylon syringe filter on the morning of the experimental day, then stored in airtight vials at 4°C until analysis within 60 days using an Apollo SciTech DIC Analyzer AS-C3 which incorporates the LI-7000 CO2/H2O Analyzer. Other parameters were calculated with CO2sys.
Data are unprocessed.
BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- nd (no data) was entered into all blank cells
- replaced spaces with underscores
|treatment_rep_culture_day||Treatment replicate that names the sample and the day of semi-continuous culture||unitless|
|alkalinity||total alkalinity of the culture material removed||micromoles/kilogram (umol/kg)|
|DIC||dissolved inorganic carbon||micromoles/kilogram (umol/kg)|
|pCO2||Partial pressure of carbon dioxide in the water body by computation from pH and alkalinity||parts per million by volume (ppmv)|
|description||description of the sub-dataset: Rhodomoas: no grazers; Rhodomonas_and_Coxliella: grazers present||unitless|
|Dataset-specific Instrument Name|| |
LI-7000 CO2/H2O Analyzer
|Generic Instrument Name|| |
LI-COR LI-7000 Gas Analyzer
|Generic Instrument Description|| |
The LI-7000 CO2/H2O Gas Analyzer is a high performance, dual cell, differential gas analyzer. It was designed to expand on the capabilities of the LI-6262 CO2/ H2O Gas Analyzer. A dichroic beam splitter at the end of the optical path provides radiation to two separate detectors, one filtered to detect radiation absorption of CO2 and the other to detect absorption by H2O. The two separate detectors measure infrared absorption by CO2 and H2O in the same gas stream. The LI-7000 CO2/ H2O Gas Analyzer is a differential analyzer, in which a known concentration (which can be zero) gas is put in the reference cell, and an unknown gas is put in the sample cell.
|Dataset-specific Instrument Name|
|Generic Instrument Name|| |
|Dataset-specific Description|| |
|Generic Instrument Description|| |
Instruments that incrementally add quantified aliquots of a reagent to a sample until the end-point of a chemical reaction is reached.
|Start Date|| |
|End Date|| |
Description from NSF award abstract:
The calcifying Haptophyte Emiliania huxleyi appears to be acutely sensitive to the rising concentration of ocean pCO2. Documented responses by E. huxleyi to elevated pCO2 include modifications to their calcification rate and cell size, malformation of coccoliths, elevated growth rates, increased organic carbon production, lowering of PIC:POC ratios, and elevated production of the active climate gas DMS. Changes in these parameters are mechanisms known to elicit alterations in grazing behavior by microzooplankton, the oceans dominant grazer functional group. The investigators hypothesize that modifications to the physiology and biochemistry of calcifying and non-calcifying Haptophyte Emiliania huxleyi in response to elevated pCO2 will precipitate alterations in microzooplankton grazing dynamics. To test this hypothesis, they will conduct controlled laboratory experiments where several strains of E. huxleyi are grown at several CO2 concentrations. After careful characterization of the biochemical and physiological responses of the E. huxleyi strains to elevated pCO2, they will provide these strains as food to several ecologically-important microzooplankton and document grazing dynamics. E. huxleyi is an ideal organism for the study of phytoplankton and microzooplankton responses to rising anthropogenic CO2, the effects of which in the marine environment are called ocean acidification; E. huxleyi is biogeochemically important, is well studied, numerous strains are in culture that exhibit variation in the parameters described above, and they are readily fed upon by ecologically important microzooplankton.
The implications of changes in microzooplankton grazing for carbon cycling, specifically CaCO3 export, DMS production, nutrient regeneration in surface waters, and carbon transfer between trophic levels are profound, as this grazing, to a large degree, regulates all these processes. E. huxleyi is a model prey organism because it is one of the most biogeochemically influential global phytoplankton. It forms massive seasonal blooms, contributes significantly to marine inorganic and organic carbon cycles, is a large producer of the climatically active gas DMS, and is a source of organic matter for trophic levels both above and below itself. The planned controlled study will increase our knowledge of the mechanisms that drive patterns of change between trophic levels, thus providing a wider array of tools necessary to understand the complex nature of ocean acidification field studies, where competing variables can confound precise interpretation.