dissolved oxygen do and dissolved organic carbon doc in the cape fear river estuary n.
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Dissolved Oxygen (DO) and Dissolved Organic Carbon (DOC) in the Cape Fear River Estuary PowerPoint Presentation
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Dissolved Oxygen (DO) and Dissolved Organic Carbon (DOC) in the Cape Fear River Estuary

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Dissolved Oxygen (DO) and Dissolved Organic Carbon (DOC) in the Cape Fear River Estuary

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  1. Dissolved Oxygen (DO) and Dissolved Organic Carbon (DOC) in the Cape Fear River Estuary Lauren Thompson Chemical and Physical Analysis of Seawater Fall 2008

  2. Why DO? • Frequently measured analyte • General water conditions • Oxic, suboxic, anoxic • implications to fish health • Important marker of biological activity of the water body • Indicates Redox conditions

  3. Four Main Controls of DO • Physical- • Temperature • Salinity • Most DO in cold, fresh water. • Biological • Photosynthesis: produces of DO • CO2+ H2O CH2O+ O2 • Respiration: use of DO • CH2+ O2 CO2+ H2O

  4. YSI • Measured in situ with a YSI meter • Cathode Reaction • Reduction- 02+ 4e- 202- • Anode Reaction • Oxidation- 4Ag 4Ag+ 4e- • Overall Reaction • 4Ag 4Ag+ +4e- • DO measured is proportional to current flow of the meter.

  5. Physical Controls Cruise 1 Temp: 22.4oC Cruise 2 Temp: 16.5oC

  6. DO Comparison

  7. DO Comparison

  8. What about DOC? Dominant control of DO in Cape Fear is utilization. CH2 + O2 CO2 + H2O DOC causes a decrease in %O2 saturation as salinity increases.

  9. What is DOC? • Dissolved Organic Carbon • Operational definition- material that passes through a filters 0.2-0.7µM • Cape Fear is an input to the Oceans • 0.2 x 1015 g C yr-1 • Biological Production • Excretion and Cell Lysis • Sloppy Feeding • Release from Fecal Matter

  10. Surface vs. Deep More DOC in surface.

  11. Conservative mixing Increased Salinity, Decreased DOC Salinity Effects

  12. Long-term Trend Class Data from previous 6 years!

  13. Chl-a Increased levels of Chl-a with decreasing DOC concentrations. Optical clarity of water ?

  14. Conclusions • Cruise 2 was colder than Cruise 1 by 5.9 ºC • Higher Levels of DO for Cruise 2 at all sites. • Cruises 1 & 2 showed Correlation to salinity, but it was reverse of what is expected. • Not main controlling factor. • Both Cruise 1 and Cruise 2 DOC vs. % saturation produced an inverse relationship • Surface typically had higher numbers when compared to deep. • Except Cruise 2 M18-35. • DOC has inverse relationship to Salinity • Also, inverse to chl-a. • More production with decreased DOC. • Main Control is Utilization.