Hi Folks, I would like to respond to this intricate assessment by Andrew.
"Albert is right that the ESS excursions are shallow. All cold-environment excursions tend to be shallow as the clathrathe stability zone terminates closer to mean sea level in cold waters. Therefore high latitude methane ebulliation is less susceptible to dissolution. As such, oxygen treatments are less likely to be effective, as dissolution is a necessary precursor for aerobic metabolism of the methane excursions". The ESAS excursions are both a challenge and a benefit duo to the shallowness, yet it is not the only area of concern. Regardless of the reduction of dissolution, methane bubbles will be present and will represent a large percentage of surface out gassing to the atmosphere. As to oxygenation being less effective duo to cold water inhibiting bubble production, allow me to take that from two different angles. First, maintaining/enhancing the health of the biotic web, is important in metabolizing the dissolved methane and is far better at it than any effort we can even contemplate.... realistically. Second, as we know, the increased GW induced heating in that region will potentially illuminate that conditional situation.....Let's hope we have time to avoid that. . "Steps could be taken to improve dissolution, such as by mechanically breaking up the bubbles, or pumping seawater across bubble vents which has low levels of solute gases in. This will tend to increase dissolution. However, the results obtained are likely to be no better than could be achieved by seeking to capture methane bubbles for flaring or bottling/piping, and without the according economic benefits." Industrializing these very fragile/remote areas for "economic benefit" is a thought pattern that has basically brought us to where we are. Flaring methane within the atmospheric Polar Cell region would be mainlining ozone depleting compounds directly to the Ozone Hole. ESAS just happens to be directly under the ascending cell flow. I think flaring, on a mass scale, would be profoundly catastrophic. Mechanical shearing of bubbles/pumping seawater???? I need help understanding the rational foundation for that idea. "In environments where dissolution occurs, but where oxygen is scarce and methane therefore diffuses from the sea surface, input of oxygen into the waters may be of benefit. However, this is far from simple. As has been pointed out, disruption of benthic ecosystems due to stirring sediments and transporting surface waters or oxygen down is unlikely to be desirable." That important point is why I proposed oxygenation "well above the biotic layer" "As such, any ducts would likely need to be moored some way off the seabed, suspended between floats and weighted anchors, or actively depth controlled using towed arrays from ships". Yes, that was also indicated in the original concept. Towed arrays are appropriate for localized areas needing intensive consideration. "In shallow seas this is even more difficult to acheive, as the clearance depth from the sea bed would be a significant fraction of the total depth of the water column." Multiple means of mechanically/logistically addressing deferent conditions are needed. Extreme shallow conditions could benefit from nutrient enhancement and maybe rafts of mixers autonomously roving the area guided by remote methane monitors. "I do not think it viable to use ships for this task. Oxygenation processes would have to be essentially continuous to be effective, and criss-crossing with ships is likely to be energetically and logistically expensive. In order to provide year-round power in remote areas, we would need to consider wind turbines or tidal turbines, or shore-based power. Turbines could be mounted on anchored barges, or set into the sea bed." See OOI links at the main thread. Wave power is also possible, but only in non-arctic environments. The power so generated could be used to aid downwelling, or used to pump air into ducts for venting near the sea bed." This project, if it goes forward, has the potential to stimulate needed new green energy systems through the sheer number of unit needed. I vote for methane and hydrogen fuel cells, as well as, hydrogen/methane uptake polymers. Here are a few links to that field. http://chem.hust.edu.cn/tanbien/uploads/tan46.pdf http://pubs.acs.org/doi/abs/10.1021/la0355500 http://sqma.myweb.usf.edu/pictures/P-24.pdf This is just a glimpse of what is available. Even so, with materials like these, we could engineer more advanced methane capture concepts. Being able to adsorb dissolved methane from seawater would not just allow better buoys to be developed, but could lead to mass means to cool/heat wide ocean areas and/or new industrial energy supplies. Any project of the size which is under discussion has game changing potential within the green energy issue. Energy is the foundational issue. Missing this opportunity, if it develops, would be a historic failure of thinking. I don't fully agree that there's a big risk from mixing waters in the ESS. The sea temperature under the ice is close to freezing point in winter. In summer, surface temperatures may be significantly higher, but pumping would not occur at this time. Summertime albedo enhancement of that region, through hydrosol deployment, may be crucial to year around health of the general ecosystem. In that, the ESAS is shallow and the heat stress does degrade a number of aspects within that system. Even a minor decrease in solar energy uptake by the waters could provide significant system wide benefits. Combining that heat reduction and the added oxygenation provided by hydrosols, the GW stress reduction would probably be documented within a few seasons.I do remain concerned by mass movements induced by ebulliation. Such movements are non-trivial. Indeed, domestic aquaria use ebulliation to induce mass flow through undergravel biological filters. The bubble diffusers used would have to be capable of producing small diameter bubbles which dissolve readily. These diffusers would have to be well distributed, as water around the bubble column would quickly saturate with oxygen in the event of a high mass flow of air. I believe "mass movements induced by ebulliation" you are referring to an "eruption" of methane. If I am correct, then, preventing ebullitions is what this effort is about. Such discharges, once found, can be a focal point of active conversion of the potential energy fuel to local area cooling of the water. Heat is the primary reason for such eruptions. This use of the methane energy in cooling the surrounding waters was also claimed in the first post. As such, any undersea network of bubblers would be very expensive due to the complexity, power requirements, high number of vents and extreme environment. The turbines, ducts and bubblers would need to expand over the area of an entire sea. Models and maps are now coming to my attention that allow for a focused effort on priority sites that currently exist. Selective intervention is the best way to ramp up a more broad network. The entire region(s) do not have to be blanketed with buoys. The thread under "Lecture on Methane.." is where I will try to collect the models/maps. This to me seems impractical. Far better to use SRM to prevent the warming in the first place. The policy implications between local/regional intervention and global intervention make this view unrealistic, as far as time. If we give the ocean methane issue a high priority, the need for Global SRM may be delayed.... possibly avoided One competing idea I considered is the use of foams to arrest methane bubbles on the surface. This will of course cause a reduction in oxygenation of the waters, but at least the methane could be recovered and could potentially be economically useful. I have no comment. Thanks for offering this assessment, Andrew. It is this type of questioning that can help a new concept evolve. A tree that grows without a breeze, will never weather the storm. Michael -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
