1 / 23

Spatial and Temporal Variability of pCO2 in the Great Bay Estuary System

Spatial and Temporal Variability of pCO2 in the Great Bay Estuary System. Chris Hunt, Joe Salisbury, Doug Vandemark, Janet Campbell University of New Hampshire Wade McGillis- Lamont-Doherty Earth Observatory ASLO Session SS07, Santa Fe February 5, 2007.

tavarius
Download Presentation

Spatial and Temporal Variability of pCO2 in the Great Bay Estuary System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Spatial and Temporal Variability of pCO2 in the Great Bay Estuary System Chris Hunt, Joe Salisbury, Doug Vandemark, Janet Campbell University of New Hampshire Wade McGillis- Lamont-Doherty Earth Observatory ASLO Session SS07, Santa Fe February 5, 2007

  2. 44 km^2 of estuary, 230 km of shoreline • Tidally dominated • Freshwater typically represents only 2% of tidal prism • Tidal height ~2m • Observed flushing time is 18 days from head of estuary (during high river flow)

  3. ~10 km to Gulf of Maine

  4. From Oczkowski, A. 2002, ‘Riverine inputs of nutrients to Great Bay, NH (USA)’, MS Thesis, Department of Earth Science, UNH, Durham

  5. Fast equilibrator for continuous pCO2 measurements. R/V Camden Belle Flow-through system equipped to measure Fl-Chl, Fl-CDOM, beam attenuation, DO, Temp, and Salinity. Seawater is pumped through the system at a rate of 20L/min.

  6. After a historic flood: June 5-6, 2006 After a drought: Oct 4-6, 2005 After spring runoff: April 7 & 10, 2006 During Fall low flow: October 5-6, 2006

  7. Apr 06 Oct 05 Salinity (psu) Oct 06 Jun 06

  8. Oct 2005 Apr 2006 Oct 2006 Jun 2006

  9. Apr 06 Oct 05 pCO2 (uatm) Oct 06 Jun 06

  10. Conservative mixing line TA (umol/kg) Slope=57.8 Int=316.3 Salinity (psu) K0 K1 H2CO3 HCO3- + H+ CO2(f) + H2O K2 CO3= + H+ Conservative pCO2 calculated using carbonate equations from Pilson (1998) and K1 and K2 from Cai and Wang (1998) Conservative mixing line, using an abiotic oceanic endmember DIC (umol/kg) Slope=46.8 Int=467.3 Cai W.-J. and Wang Y. (1998) The chemistry, fluxes and source of carbon dioxide in the estuarine waters of the Satilla and Altahama Rivers, Georgia. Limnol. Oceanogr.43, 657-668. Pilson, M.E.Q. (1998). An Introduction to the Chemistry of the Sea. Prentice Hall, Upper Saddle River, New Jersey. Salinity (psu)

  11. Apr 06 Oct 05 pCO2 Anomaly= pCO2conservative – pCO2observed • Values >0 indicate • less CO2 than predicted • by conservative mixing • Values <0 indicate • more CO2 than predicted • by conservative mixing • Values >0 suggest • autotrophy • Values <0 suggest • heterotrophy pCO2 Anomaly Jun 06 Oct 06 (uatm)

  12. Apr 06 Oct 05 pCO2 Anomaly %= (pCO2conservative – pCO2observed) pCO2conservative • Values >0 indicate • less CO2 than predicted • by conservative mixing • Values <0 indicate • more CO2 than predicted • by conservative mixing • Values >0 suggest • autotrophy • Values <0 suggest • heterotrophy pCO2 Anomaly % Jun 06 Oct 06 (%)

  13. Conclusions • The Great Bay operates as a ‘system of systems’, with differing metabolic patterns • We infer that seasonality and climatic events have a dramatic effect upon carbon processing • Endmember contributions from rivers seem to strongly influence estuarine biogeochemistry • General classification of estuaries as heterotrophic does not describe the Great Bay system, as well as other New England estuaries (e.g. Merrimack River)

  14. Speculations • River-sourced nutrients, OC, and light limitation drive patterns of heterotrophy/autotrophy in Great Bay • Precipitation events move terrestrial labile carbon to the estuary, promoting strong heterotrophy • Inputs from municipal WWTF significantly affect estuarine carbon cycle, particularly during low river flow

  15. Oct 2006 Nitrate Oct 2005 Nitrate NO3 (umol/L) NO3 (umol/L)

  16. Future Work • Determine seasonal DIC and OC fluxes for system as a whole and individual rivers • Calculate net CO2 exchange • Use caffeine as an anthropogenic tracer • Install continuous CO2 system in Great Bay?

More Related