Contributors | Affiliation | Role |
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Morris, James | University of Alabama at Birmingham (UA/Birmingham) | Principal Investigator |
Lu, Zhiying | University of Alabama at Birmingham (UA/Birmingham) | Scientist |
Barreto Filho, Marcelo Malisano | University of Alabama at Birmingham (UA/Birmingham) | Student |
Walker, Melissa | University of Alabama at Birmingham (UA/Birmingham) | Student |
York, Amber D. | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Synechococcus cultures were grown under similar conditions to those described in our previous experiment with Prochlorococcus (Hennon et al., 2017). Briefly, all cultures were prepared in acid-washed conical-bottom glass centrifuge tubes containing 13 mL of artificial seawater (ASW) amended with nutrient stocks (Hennon et al., 2017) and with acid and/or base to control pCO2. ASW (per L: 28.41 g NaCl, 0.79 g KCl, 1.58 g CaCl2*2H2O, 7.21 g MgSO4*7H2O, 5.18 g MgCl2*6H2O) was sterilized in acid-washed glass bottles, amended with 2.325 mM (final concentration) of filter-sterilized sodium bicarbonate, then bubbled with sterile air overnight. Synechococcus cultures were grown in SEv (per L: 32 μM NaNO3, 2 μM NaH2PO4, 20 μL SN trace metal stock, and 20 μL F/2 vitamin stock). The primary differences between this medium and the PEv medium used in our earlier Prochlorococcus study are the nitrogen source (NO3- vs. NH4+, with molar concentration of N and N:P ratios identical to PEv) and the addition of F/2 vitamins (Hennon et al., 2017). Carbonate chemistry of each media batch was determined prior to pCO2 manipulations by measuring alkalinity and pH by titration and colorimetry, respectively (Dickson et al., 2007) and then using the oa function in seacarb package in R to determine how much hydrochloric acid and bicarbonate (for 800 ppm pCO2) or sodium hydroxide (for 400 ppm pCO2) was needed to achieve desired experimental conditions (Gattuso and Lavigne, 2009). Acid and base amendments were introduced immediately prior to inoculation. Cultures were grown in a Percival growth chamber at 21º C under 150 μmol photons m-2 s-1 on a 14:10 light:dark cycle. Synechococcus cultures were grown on a rotating tissue culture wheel at approximately 60 rpm. After addition of amendments, absorbance values at 434, 578, and 730 nm were collected both before and after injection of m-cresol purple dye, and again after a second dye injection to correct for the impact of dye addition on solution pH. Equations from (Dickson et al., 2007) were used to compute the pH. The data are provided in the form of an Excel spreadsheet containing the necessary formulas for computing the pH from the absorbance data. pH assays were performed in microtiter plates using a BioTek H1 plate reader with an automated dye injection mechanism and temperature control.
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carb_chem.csv (Comma Separated Values (.csv), 5.75 KB) MD5:fb8861fc038cf4322d40644bab2c7684 Primary data file for dataset ID 883120 |
Parameter | Description | Units |
Sample | Sample Identifier | unitless |
Sample_Temp | Temperature of the sample at the time of pH measurement | degrees Celsius |
Salinity | Salinity of the medium | PSU |
volume_dye | Amount of dye injected at each injection point | milliliters (mL) |
pH_sample_with_dye_corrections | pH of the sample taking into account both dye injections | unitless |
pH_sample_without_dye_corrections | pH of the sample only considering the first dye injection | unitless |
d730_1 | Difference between initial and injection 1 A730 readings | unitless |
d730_2 | Difference between initial and injection 2 A730 readings | unitless |
Sample_A_434 | Absorbance at 434nm before dye injection | unitless |
Sample_A_578 | Absorbance at 578nm before dye injection | unitless |
Sample_A_730 | Absorbance at 730nm before dye injection | unitless |
Sample_and_Dye_A_434 | Absorbance at 434nm after 1 dye injection | unitless |
Sample_and_Dye_A_578 | Absorbance at 578nm after 1 dye injection | unitless |
Sample_and_Dye_A_730 | Absorbance at 730nm after 1 dye injection | unitless |
Sample_and_Dye_x2_A_434 | Absorbance at 434nm after 2 dye injections | unitless |
Sample_and_Dye_x2_A_578 | Absorbance at 578nm after 2 dye injections | unitless |
Sample_and_Dye_x2_A_730 | Absorbance at 730nm after 2 dye injections | unitless |
A1_to_A2sub1 | Ratio of A578:A434 after 1 injection | unitless |
A1_to_A2sub2 | Ratio of A578:A434 after 2 injections | unitless |
pK2 | pKa of the dye, corrected for salinity and temperature | unitless |
delta_A1_to_A2 | Difference in absorbance ratios between first and second dye injections | unitless |
Constant_A | Constant A = E1(HI-)/E2(HI-); extinction coefficient from Dickson et al. 2007 SOP6b eq. 7 | unitless |
Constant_B | Constant B = E1(I-2)/E2(HI-); extinction coefficient from Dickson et al. 2007 SOP6b eq. 7 | unitless |
Constant_C | Constant C = E2(I-2)/E2(HI-); extinction coefficient from Dickson et al. 2007 SOP6b eq. 7 | unitless |
Dye_Correction_Incercept_a | Intercept of regression line for the two dye injections, for correcting for effect of dye addition | unitless |
Dye_Correction_slope_b | Slope of regression line for the two dye injections, for correcting for effect of dye addition | unitless |
A1_to_A2_corrected | Ratio of A578:A434 corrected for effect of dye addition | unitless |
Dataset-specific Instrument Name | BioTek H1 plate reader |
Generic Instrument Name | plate reader |
Generic Instrument Description | Plate readers (also known as microplate readers) are laboratory instruments designed to detect biological, chemical or physical events of samples in microtiter plates. They are widely used in research, drug discovery, bioassay validation, quality control and manufacturing processes in the pharmaceutical and biotechnological industry and academic organizations. Sample reactions can be assayed in 6-1536 well format microtiter plates. The most common microplate format used in academic research laboratories or clinical diagnostic laboratories is 96-well (8 by 12 matrix) with a typical reaction volume between 100 and 200 uL per well. Higher density microplates (384- or 1536-well microplates) are typically used for screening applications, when throughput (number of samples per day processed) and assay cost per sample become critical parameters, with a typical assay volume between 5 and 50 µL per well. Common detection modes for microplate assays are absorbance, fluorescence intensity, luminescence, time-resolved fluorescence, and fluorescence polarization. From: http://en.wikipedia.org/wiki/Plate_reader, 2014-09-0-23. |
NSF Award Abstract:
Carbon dioxide released from fossil fuels is causing the ocean to become more acidic. Much attention has been given to how this will affect shelled animals like corals, but acidification also affects the algae that form the base of the ocean food chain. It is possible that future algal communities will look very different than they do today, with potentially negative consequences for fisheries, recreation, and climate. Alternatively, it is possible that these algae will be able to adapt rapidly enough to avoid the worst of it. This study looks at algae adapting to acidification in real time in the lab, focusing on "marketplace" interactions between the algae and the bacteria they live alongside. The researchers also go to sea to learn whether adaptations from the lab experiments are beneficial under real-world conditions. Ultimately, this project is helping scientists better understand how the ocean's most important and most overlooked organisms will respond to the changes humans are causing in their habitat. The researchers also use their scientific work to create fun educational opportunities from grade school to college, including agar art classes where students learn about microbial ecology by "painting" with freshly-isolated ocean bacteria.
The effect of ocean acidification on calcifying organisms has been well-studied, but less is known about how changing pH will affect phytoplankton. Previous work showed that the mutualistic interaction between the globally abundant cyanobacterium Prochlorococcus and its "helper" bacterium Alteromonas broke down under projected future CO2 conditions, leading to a strong decrease in the fitness of Prochlorococcus. It is possible that such interspecies interactions between microbes are important for many ecological processes, but a lack of understanding of how these interactions evolve makes it difficult to predict how important they are. This project is using laboratory evolution experiments to discover how evolution shapes the interactions between bacteria and algae like Prochlorococcus, and how these co-evolutionary dynamics might influence the biogeochemical processes that shape Earth's climate. Four research cruises to the Bermuda Atlantic Time Series are also planned to study how natural algal/bacterial communities respond to acidification, and whether evolved microbes from laboratory experiments have a competitive advantage in complex, natural communities exposed to elevated CO2. The ultimate goal of this project is to gain a mechanistic understanding of microbial interactions that can be used to inform models of Earth's oceans and biological feedbacks on global climate.
Funding Source | Award |
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NSF Division of Ocean Sciences (NSF OCE) |