Climate Effects: Nutrient Fluxes & Carbon Fixation
March 21, 2009 New Orleans, LA
The University of Southern Mississippi Department of Marine Science
Scott P. Milroy, Ph.D.
CO2 and Global Climate Change – There is a Reason for the Controversy…
Atmospheric concentrations of CO2 have risen ~20% since 1960.
Less than 0.04% of the Earth’s atmosphere is CO2. Water vapor (H2O) is the most abundant greenhouse gas in the atmosphere.
(http://lwf.ncdc.noaa.gov/oa/climate/gases.html)
H2O is 2X more effective at climate warming than CO2 and is 12X more abundant!
(http://www.nasa.gov/topics/earth/features/vapor_warming.html)
The Global Climate Change Controversy – A Warming Earth Will Accentuate:
Greenhouse Effect vs Heat Capacity
Thermal Expansion (Sea Level Rise)
The Global Climate Change Controversy – A Warming Earth Will Accentuate:
Increased Cloud Cover (Albedo)
The Global Climate Change Controversy – A Warming Earth Will Accentuate:
Torrential Rains (Extreme Weather)
The Global Climate Change Controversy – A Warming Earth Will Accentuate:
Increased Weathering (Nutrient/Sediment Flux) (High Nutrients / Low Light)
Utilization of Key Nutrients – Carbon, Nitrogen, and Phosphorus
The availability of C / N / P / ☼ in the Gulf of Mexico will determine:
Carbon Fixation
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
Availability of Key Nutrients – Where Does N+P Come From?
http://water.usgs.gov/nawqa/sparrow/gulf_findings/faq.html
Availability of Key Nutrients – Where Does N+P Come From?
http://water.usgs.gov/nawqa/sparrow/gulf_findings/faq.html
Availability of Key Nutrients – Where Does N+P Come From?
http://water.usgs.gov/nawqa/sparrow/gulf_findings/faq.html
Availability of Key Nutrients – Where Does N+P Come From?
http://water.usgs.gov/nawqa/sparrow/gulf_findings/faq.html
Availability of Key Nutrients – Where Does All That N+P Go?
Ideal N:P ≈ 15-16
N:P ≈ 21
(P-Limited)
N:P ≈ 8.6
(N-Limited)
Additional sources of nitrogen will increase productivity
http://www.epa.gov/msbasin
Coastal Producers – Ecosystems Typical of the Gulf of Mexico
Marshgrass Meadows
Mangrove Swamps
Seagrass 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.
Coastal Producers – Ecosystems Typical of the Gulf of Mexico
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. Microalgae Macroalgae Algae Blooms
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 CO2, N+P…
Deep Earth Burial
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 Ocean Transport