1. Greenhouse Gas Emissions Following Seasonal
Flooding of Southeast Asian Tropical River Deltas
Amy Salvador[2] Michael Schaefer[1] Kate Roberts[1] Marco Keiluweit[1] Sam Ying[2] Scott
Fendorf[1]
August 13th 2015
[1] Stanford University [2]University of California, Riverside
32. O2
Results of Flooding Conditions
CO2
5/10/15 5/12/15 5/14/15 5/16/15 5/18/15 5/20/15 5/22/15 5/24/15
May 10 – 24,2015
Small CO2 Peak
Flooding Event
CO2
35. CO2
CO2 Exchange in Flooded Conditions
5/10/15 5/12/15 5/14/15 5/16/15 5/18/15 5/20/15 5/22/15 5/24/15
May 10 – 24,2015
Small CO2 Peak
Flooding Event
CO2
36. O2
CO2 Exchange in Dry Conditions
CO2
5/10/15 5/12/15 5/14/15 5/16/15 5/18/15 5/20/15 5/22/15 5/24/15
May 10 – 24,2015
CO2 Flux
Flooding Event
CO2
59. “Organic carbon oxidation
rates, as measured by
dissolved inorganic carbon
(DIC) concentrations,
further support arsenic
liberation via near-surface
anaerobic microbial
respiration.”
We already know that GHG’s are steadily rising and that humans contribute a lot towards emissions, but it is also important to know that soil is an important agent to produce and absorb these gases.
Loss of biodiversity
Changes in water system in terms of precipitation, runoff events, and rising sea levels, ocean acidification. But also change in clean water availability.
Changes in soil system in terms of arable soil lost via erosion and
Health issues following flooding/drying – diarrhea, water contaminants (arsenic, chromium, fe/al toxicity)
From researching gases emitted following variations of flooded and non-flooded conditions as exhibited naturally by flooding and drying, we can project how human use of land like flooding of rice paddies or drying of wetlands impacts the GHG gas concentrations and the following side effects.
We already know that GHG’s are steadily rising and that humans contribute a lot towards emissions, but it is also important to know that soil is an important agent to produce and absorb these gases.
Loss of biodiversity
Changes in water system in terms of precipitation, runoff events, and rising sea levels, ocean acidification. But also change in clean water availability.
Changes in soil system in terms of arable soil lost via erosion and
Health issues following flooding/drying – diarrhea, water contaminants (arsenic, chromium, fe/al toxicity)
From researching gases emitted following variations of flooded and non-flooded conditions as exhibited naturally by flooding and drying, we can project how human use of land like flooding of rice paddies or drying of wetlands impacts the GHG gas concentrations and the following side effects.
Project from one small area that we assume is exemplary of whole delta and able to apply assumptions to a larger whole of similar tropical climates.
So then, what we must consider, is the effectiveness of each compound in the atmosphere. According to the EPA, N2O has 298 times the capacity to trap heat in the atmosphere than CO2. And CH4 has 25 times the effectiveness.
http://www.epa.gov/ghgreporting/documents/pdf/2013/documents/2013-data-elements.pdf
Fossil fuels are the remnants of ancient life but living organisms are also important to the composition of the atmosphere and much of aquatic chemistry
2 stroke process of vegetative biomass converts CO2 and H2O into O2 and complex sugars that they can dump into the soil.
The other side of this process is oxidation or respiration in which microbes can eat these complex sugars, breathe in O2 and exhale CO2 much like us humans do. And on their other end emit CH4 and excrete Nitrogen as ammonia also like we do.
BUT when we humans run out of air, that’s it, we die. But what is so great about microbes is that they don’t need O2 as much as we do. They can live in O2 free conditions and take up other compounds that remain in the soil
Fossil fuels are the remnants of ancient life but living organisms are also important to the composition of the atmosphere and much of aquatic chemistry
2 stroke process of vegetative biomass converts CO2 and H2O into O2 and complex sugars that they can dump into the soil.
The other side of this process is oxidation or respiration in which microbes can eat these complex sugars, breathe in O2 and exhale CO2 much like us humans do. And on their other end emit CH4 and excrete Nitrogen as ammonia also like we do.
BUT when we humans run out of air, that’s it, we die. But what is so great about microbes is that they don’t need O2 as much as we do. They can live in O2 free conditions and take up other compounds that remain in the soil
Terrestrial Biome successfully sequesters or stores Carbon and Nitrogen into the soil. Or you can look at it on the opposite spectrum that this stored C and N is available for microbes to use them and emit them into the atmosphere.
Terrestrial Biome successfully sequesters or stores Carbon and Nitrogen into the soil. Or you can look at it on the opposite spectrum that this stored C and N is available for microbes to use them and emit them into the atmosphere.
Water is the medium that weathers minerals and transfers elements between the soil/water interface.
*What can this tell us?
- organic carbon and oxygen also in water released from soil and can interact with other elements.
ie. PO43- and Fe stick to organics and keep them in aqueous phase rather than gaseous.
What youre looking at is the soil moisture over the whole globe. What we can we see of the tropics around the equator is great fluctuations in wet/dry periods.
WHY?
Changes such as drying or flooding can result in drastic changes of Carbon sequestration or GHG emissions.
The Mekong is an example of transient moisture regimes. Such as extreme wetting and drying and very fast and drastic vegetation growing seasons and likewise dying seasons. Which is why the Mekong is interesting to study.
Picture source:
http://www.mdpi.com/2072-4292/5/10/5122/htm
Leads to question how is soil temperature affect gas emissions?
At the site, gases were taken off of flooded as well as dried soil.
Water sample were also taken to view at the carbon and nitrogen pool in the aqueous phase.
Soil sample were taken to measure the total carbon and nitrogen storage in the soil available to microbes.
Soil moisture lysimeters permanently installed to measure every 30 minutes.
At the site, gases were taken off of flooded as well as dried soil.
Water sample were also taken to view at the carbon and nitrogen pool in the aqueous phase.
Soil sample were taken to measure the total carbon and nitrogen storage in the soil available to microbes.
Soil moisture lysimeters permanently installed to measure every 30 minutes.
At the site, gases were taken off of flooded as well as dried soil.
Water sample were also taken to view at the carbon and nitrogen pool in the aqueous phase.
Soil sample were taken to measure the total carbon and nitrogen storage in the soil available to microbes.
Soil moisture lysimeters permanently installed to measure every 30 minutes.
At the site, gases were taken off of flooded as well as dried soil.
Water sample were also taken to view at the carbon and nitrogen pool in the aqueous phase.
Soil sample were taken to measure the total carbon and nitrogen storage in the soil available to microbes.
Soil moisture lysimeters permanently installed to measure every 30 minutes.
At the site, gases were taken off of flooded as well as dried soil.
Water sample were also taken to view at the carbon and nitrogen pool in the aqueous phase.
Soil sample were taken to measure the total carbon and nitrogen storage in the soil available to microbes.
Soil moisture lysimeters permanently installed to measure every 30 minutes.
At the site, gases were taken off of flooded as well as dried soil.
Water sample were also taken to view at the carbon and nitrogen pool in the aqueous phase.
Soil sample were taken to measure the total carbon and nitrogen storage in the soil available to microbes.
Soil moisture lysimeters permanently installed to measure every 30 minutes.
At the site, gases were taken off of flooded as well as dried soil.
Water sample were also taken to view at the carbon and nitrogen pool in the aqueous phase.
Soil sample were taken to measure the total carbon and nitrogen storage in the soil available to microbes.
Soil moisture lysimeters permanently installed to measure every 30 minutes.
More labile carbon available during flooding at surface. At depth more stable carbon because less biotic uptake
More labile carbon available during flooding at surface. At depth more stable carbon because less biotic uptake
More labile carbon available during flooding at surface. At depth more stable carbon because less biotic uptake
Smaller fraction, has more surface area to hold carbon BUT also less diffusion of oxygen under flooded conditions to release carbon as CO2.
Smaller fraction hold more Carbon. Less oxygen available in smaller fraction especially under flooded conditions
Smaller fraction hold more Carbon. Less oxygen available in smaller fraction especially under flooded conditions
Without oxygen my guess is that less iron oxides formed as well which would keep carbon out of the dense fraction.
![Greenhouse Gas Emissions Following Seasonal
Flooding of Southeast Asian Tropical River Deltas
Amy Salvador[2] Michael Schaefer[1] Kate Roberts[1] Marco Keiluweit[1] Sam Ying[2] Scott
Fendorf[1]
August 13th 2015
[1] Stanford University [2]University of California, Riverside](https://image.slidesharecdn.com/622f8efa-d58e-475f-9615-baf9bfb9f91e-160721163256/85/GHG-presentation-2-Autosaved-1-320.jpg)
