Abstract Details
(2020) Challenges in Quantifying Long-Term Air–water Carbon Dioxide Flux Using Estuarine Water Quality Data: Case Study for Chesapeake Bay
Herrmann M, Najjar R, Da F, Friedman J, Friedrichs M, Goldberger S, Menendez A, Shadwick E, Stets E & St-Laurent P
https://doi.org/10.46427/gold2020.1026
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12c: Plenary Hall, Wednesday 24th June 22:21 - 22:24
Maria Herrmann
View all 2 abstracts at Goldschmidt2020
View abstracts at 2 conferences in series
Raymond Najjar View all 4 abstracts at Goldschmidt2020
Fei Da View all 2 abstracts at Goldschmidt2020
Jaclyn Friedman View all 2 abstracts at Goldschmidt2020
Marjorie Friedrichs View all 4 abstracts at Goldschmidt2020
Sreece Goldberger
Alana Menendez
Elizabeth Shadwick View all 4 abstracts at Goldschmidt2020
Edward Stets View all 3 abstracts at Goldschmidt2020 View abstracts at 2 conferences in series
Pierre St-Laurent View all 3 abstracts at Goldschmidt2020 View abstracts at 2 conferences in series
Raymond Najjar View all 4 abstracts at Goldschmidt2020
Fei Da View all 2 abstracts at Goldschmidt2020
Jaclyn Friedman View all 2 abstracts at Goldschmidt2020
Marjorie Friedrichs View all 4 abstracts at Goldschmidt2020
Sreece Goldberger
Alana Menendez
Elizabeth Shadwick View all 4 abstracts at Goldschmidt2020
Edward Stets View all 3 abstracts at Goldschmidt2020 View abstracts at 2 conferences in series
Pierre St-Laurent View all 3 abstracts at Goldschmidt2020 View abstracts at 2 conferences in series
Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.
Submitted by Christopher Sabine on Tuesday 16th June 21:43
You mentioned that the outgassing decreased with time. Can you determine where these changes were most prominent? When you broke the bay into 8 areas, the strongest outgassing was in the upper bay. Has there been a decrease in that outgassing in the upper bay that could account for the decrease in the overall bay fluxes, or have the changes been more uniform across all the areas?
Thank you for your question, Chris. The decrease with time is actually most prominent in the lower, mostly polyhaline part of the estuary, not in the upper bay. If you look on our map, this would be in regions 6 through 8.
You mentioned that the outgassing decreased with time. Can you determine where these changes were most prominent? When you broke the bay into 8 areas, the strongest outgassing was in the upper bay. Has there been a decrease in that outgassing in the upper bay that could account for the decrease in the overall bay fluxes, or have the changes been more uniform across all the areas?
Thank you for your question, Chris. The decrease with time is actually most prominent in the lower, mostly polyhaline part of the estuary, not in the upper bay. If you look on our map, this would be in regions 6 through 8.
Submitted by Andreas Andersson on Tuesday 23rd June 04:36
I was surprised that the alkalinity, a modeled parameter, contributed the smallest uncertainty to the flux estimate, and that pH which was actually measured contributed the highest uncertainty. Could you elaborate on why this was the case?
This is a great question, Andreas. Hight sensitivity of pCO2 to pH is a fundamental property of the carbonate equilibria. In our pCO2 calculation we used four inputs: temperature, salinity, alkalinity, and pH. To investigate sensitivity to each input, we calculated pCO2 over the observed range of a given variable, holding the other three variables constant at their approximate mean values for the study period. It turned out that at pH values below 8, the sensitivity of pCO2 to pH is roughly an order of magnitude greater that to the other inputs.
I was surprised that the alkalinity, a modeled parameter, contributed the smallest uncertainty to the flux estimate, and that pH which was actually measured contributed the highest uncertainty. Could you elaborate on why this was the case?
This is a great question, Andreas. Hight sensitivity of pCO2 to pH is a fundamental property of the carbonate equilibria. In our pCO2 calculation we used four inputs: temperature, salinity, alkalinity, and pH. To investigate sensitivity to each input, we calculated pCO2 over the observed range of a given variable, holding the other three variables constant at their approximate mean values for the study period. It turned out that at pH values below 8, the sensitivity of pCO2 to pH is roughly an order of magnitude greater that to the other inputs.
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