1. Climate Effects: Nutrient Fluxes & Carbon Fixation The University of Southern Mississippi Department of Marine Science Scott P. Milroy, Ph.D. March 21, 2009 New Orleans, LA

3. CO 2 and Global Climate Change – There is a Reason for the Controversy… Atmospheric concentrations of CO 2 have risen ~20% since 1960. Less than 0.04% of the Earth’s atmosphere is CO 2. Water vapor (H 2 O) is the most abundant greenhouse gas in the atmosphere. (http://lwf.ncdc.noaa.gov/oa/climate/gases.html) H 2 O is 2X more effective at climate warming than CO 2 and is 12X more abundant! (http://www.nasa.gov/topics/earth/features/vapor_warming.html)

4. The Global Climate Change Controversy – A Warming Earth Will Accentuate: Thermal Expansion (Sea Level Rise) Greenhouse Effect vs Heat Capacity

5. The Global Climate Change Controversy – A Warming Earth Will Accentuate: Increased Cloud Cover (Albedo)

6. The Global Climate Change Controversy – A Warming Earth Will Accentuate: Torrential Rains (Extreme Weather)

7. The Global Climate Change Controversy – A Warming Earth Will Accentuate: Increased Weathering (Nutrient/Sediment Flux) (High Nutrients / Low Light)

8. Utilization of Key Nutrients – Carbon, Nitrogen, and Phosphorus The availability of C / N / P / ☼ in the Gulf of Mexico will determine: The rate and overall amount of photosynthesis (i.e. food production via carbon fixation). The diversity and overall biomass of those producers. The diversity and overall biomass of opportunistic consumers. C/N/P are “locked away” in the biomass Carbon Fixation

9. Availability of Key Nutrients – Where Does N+P Come From? http://water.usgs.gov/nawqa/sparrow/gulf_findings/faq.html

10. Availability of Key Nutrients – Where Does N+P Come From? http://water.usgs.gov/nawqa/sparrow/gulf_findings/faq.html

11. Availability of Key Nutrients – Where Does N+P Come From? http://water.usgs.gov/nawqa/sparrow/gulf_findings/faq.html

12. Availability of Key Nutrients – Where Does N+P Come From? http://water.usgs.gov/nawqa/sparrow/gulf_findings/faq.html

13. Availability of Key Nutrients – Where Does All That N+P Go? http://www.epa.gov/msbasin N:P ≈ 21 (P-Limited) N:P ≈ 8.6 (N-Limited) Ideal N:P ≈ 15-16 Additional sources of nitrogen will increase productivity

14. Coastal Producers – Ecosystems Typical of the Gulf of Mexico Marshgrass MeadowsMangrove SwampsSeagrass Meadows These producers remove C / N / P from coastal waters and have relatively slow turnover rates. Increased run-off (turbid N+P) will favor marshgrasses and disfavor seagrasses; increased global temperatures will favor mangroves.

15. Coastal Producers – Ecosystems Typical of the Gulf of Mexico MicroalgaeMacroalgaeAlgae Blooms These producers remove C / N / P from coastal waters but have rapid turnover rates. Increased run-off (turbid N+P) will favor green macroalgae (Chlorphyta) and shade-adapted / quick-growing phytoplankton. Diatoms will be favored due to concomitant silica run-off; nitrogen-fixers will be favored if nitrogen is limited.

16. Nutrient Sequestration – Limiting the Bioavailability of C / N / P Long-term burial of organic material (full of C/N/P) will prevent microbial reconversion into CO 2, N+P… The secret is to encourage C/N/P scrubbing (via carbon fixation), then bury the biomass in the deep earth or deep ocean. Turbid rivers (like the Mississippi) are doing just that! Deep Earth Burial Deep Ocean Transport