Andrew,
I’m not sure I understand your comment that deep water isn’t that deep. Typical numbers for the shallow ocean are a depth of 200 meter, with a thermocline between 200 and 1000 meters and a very consistent temperature and salinity below 1000 meters. See, for example: https://oceanservice.noaa.gov/facts/thermocline.html One could bring the deep ocean from 1000 meters to surface in a sealed tube; it would take energy. I don’t know the permanent salt fountain well enough to comment on it. Peter Peter Flynn, P. Eng., Ph. D. Emeritus Professor and Poole Chair in Management for Engineers Department of Mechanical Engineering University of Alberta peter.fl...@ualberta.ca cell: 928 451 4455 *From:* Andrew Lockley [mailto:andrew.lock...@gmail.com] *Sent:* Friday, September 15, 2017 11:54 AM *To:* Peter Flynn <pcfl...@ualberta.ca> *Cc:* Jason Zhou <jasonsj.z...@gmail.com>; geoengineering < geoengineering@googlegroups.com>; kcalde...@stanford.edu *Subject:* RE: [geo] SOS 2017 Session spotlight 4 - Ocean NETs - CO2 Sequestration Via Ocean-Based Negative Emissions Technologies Thanks Peter. However, you don't address whether pumping water into sealed tubes or greenhouses would be viable. Deep water isn't that deep - water for my toilet is pumped much further. As long as the water lifted was kept away from the atmosphere and surface ocean, it should be effective at fertilization of algae without releasing CO2 A On 15 Sep 2017 18:15, "Peter Flynn" <pcfl...@ualberta.ca> wrote: This prompts several comments, and apologies for the delay and to those for whom this is too basic: 1. The ocean can be thought of as two relatively independent bodies of water, the shallow and deep ocean. There is a fairly sharp boundary between the two, called the thermocline. Transfer between the two is limited, as discussed below. Once something in solution is in the deep ocean, on average its residence time before getting to the shallow ocean is 600 to 1000 years. This is an average; there are regions of the ocean where circulation between the deep and shallow ocean is very limited, and the site specific residence time is longer. The deep ocean is cold and dense. Mixing with the shallow ocean is energetically difficult because of the energy required to move a dense element up against gravity across the thermocline into a less dense zone. 2. The interaction between shallow and deep is limited to downwelling and upwelling currents. There are two major zones of downwelling current, a zone in the north Atlantic called the GIN (named for its proximity to Greenland, Iceland, and Norway) and a zone in the Antarctic by the Weddell Sea. The GIN downwelling current is called the North Atlantic Deep Water (NADW), and is the countervailing flow to the Gulf Stream. Downwelling is driven by a combination of temperature and high salinity (the high salinity is in part driven by evaporation in the Mediterranean Sea, a current from which joins the Gulf Stream). NADW and the companion Gulf Stream were interrupted for about 1200 years when Lake Agassiz, a glacial fresh water lake in North America, flowed into the Atlantic after an ice dam melted. The result was a 1200 year European cold period known as the Younger Dryas. Europe has centers of high population at latitudes higher than any other region on the globe; the Gulf Stream is credited for enabling this. One concern cited about global warming is that melting of Greenland ice could interrupt the NADW / Gulf Stream again: the irony is that an early product of global warming could be a European “ice age”. 3. Songjian Zhou and I looked at whether one could move CO2 from the atmosphere into the deep ocean by increasing the concentration of CO2 in NADW. Our answer was no: the surface water descending into the NADW was saturated in CO2. But the deep ocean is not saturated in CO2, because of its higher pressure. 4. Hence discussion of moving deep ocean water into the shallow ocean baffles me. Yes: it contains nutrients. But it also contains CO2, which would flash as the pressure dropped and temperature increased. It strikes me that we should think of the deep ocean as the sink for CO2, not a source of a “fix”. Any plan to use the nutrients in the deep ocean to grow marine biomass to be sunk into the deep ocean (or utilized as biofuel) would have to be carefully tested against the CO2 release. 5. Glen Tichkowsky and I looked at a scheme in which ocean side pools of sea water would be used to grow algae. Evaporation would increase the salinity of the pond to a point where the water could be moved as a batch into the deep ocean without pumping. The rate limiting step, by an order of magnitude, was the rate of transfer of CO2 from atmosphere to ocean; it was sufficiently slow to make the cost of carbon sequestration by this scheme prohibitive. I understood after this work why commercial algae growing operations often include agitation (to enhance mass transfer) or CO2 injection. Transferring CO2 into solution is well served by a higher concentration, e.g. flue gas. I hope this is helpful. Peter Peter Flynn, P. Eng., Ph. D. Emeritus Professor and Poole Chair in Management for Engineers Department of Mechanical Engineering University of Alberta peter.fl...@ualberta.ca cell: 928 451 4455 <(928)%20451-4455> *From:* kcalde...@gmail.com [mailto:kcalde...@gmail.com] *On Behalf Of *Ken Caldeira *Sent:* Monday, September 11, 2017 7:03 AM *To:* Geoengineering <Geoengineering@googlegroups.com> *Subject:* [geo] SOS 2017 Session spotlight 4 - Ocean NETs - CO2 Sequestration Via Ocean-Based Negative Emissions Technologies fyi [image: http://sable.madmimi.com/view?id=37127.2887543.1.7549b994549320031d05f495dbf42a2e] Sustainable Ocean Summit 2017 SESSION SPOTLIGHT Ocean NETs: CO2 Sequestration Via Ocean-Based Negative Emissions Technologies (NETs) The Internatio [image: SOS2017 bannerRegistrationOpen 600x150px] <http://sable.madmimi.com/c/37127?id=2887543.2303.1.c94303a2dc2c5c07d90790b5f2ba98d4> Sustainable Ocean Summit 2017 SESSION SPOTLIGHT <http://sable.madmimi.com/c/37127?id=2887543.2304.1.a0bb2736e6402dc798ad4baa8e92c3d4> [image: ***] Ocean NETs: CO2 Sequestration Via Ocean-Based Negative Emissions Technologies (NETs) [image: Screen Shot 2017-09-08 at 21.10.24] <http://sable.madmimi.com/c/37127?id=2887543.2305.1.93a67d8d56ade51b064a6de73b758487> The International Climate Agreement (Paris 2015) requires negative emission technologies (NETs) to remove carbon dioxide from the atmosphere in order to meet planetary safe limits. NETs need to transfer carbon from the atmosphere to a safe and environmentally sound storage. Developing and implementing NETs are critical to all industries with a carbon footprint who already or will in the near future have a price on their carbon output. Although there is much attention to potential land based NETs, there is growing evidence that the ocean is the dominant player in global carbon cycling and storage and in the planet’s temperature regulation. This means that ocean-based NETs must be given serious consideration for their potential to make a significant contribution to climate mitigation. Chemical and biological Ocean NETs are being explored, including: ocean alkalinity shifts (introducing bicarbonates), direct CO2 injection (seabed and water column), growing seaweed for deep ocean deposition, expansion of coastal ecosystems that store carbon, adjusting ocean primary productivity (e.g. artificial upwelling, addition of macronutrients nitrogen and/or phosphorus, addition of trace elements such as iron and silicon, enhanced light penetration, promoting the growth of nitrogen fixing cyanobacteria). Researchers, private enterprises and public bodies exploring Ocean NETs coordination could benefit from a structure and process to enhance coordination and exchange. The World Ocean Council (WOC) is working to address this by developing a global Ocean NET platform to bring together science, policy, business and other interests. *The SOS 2017 session on “Ocean NETs: CO2 Sequestration Via Ocean-Based Negative Emissions Technologies (NETs)”* will address: • What are the requirements of the International Climate Agreement (Paris 2015) for negative emission technologies (NET’s) to remove atmospheric CO2 to meet planetary safe limits for global temperatures? • What are the potential ocean-based NETs, what science is available on them and what are the risks and benefits of Ocean NETs? • What is needed to advance careful, science-based consideration of Ocean NETs as a potentially viable, important means to address increasing atmospheric CO2? The SOS 2017 session will focus on tangible goals that can assist in advancing the evaluation of Ocean NETs, e.g. determining the potential impact and status of Ocean NETs; identifying research gaps and unknowns; reviewing the cost of implementation of Ocean NETs; reviewing the legal framework for Ocean NETs; exploring the conceptual design of a future multipurpose Ocean NET station for capturing CO2, producing food, generating power, and interacting with other ocean users. With a cluster of innovative ocean technologies there is significantly more potential to build commercially viable ocean enterprises that help ensure that innovative NET solutions combine the very best ocean technologies and skills in multi-functional marine technology sites housing and enabling Ocean NETs. To better understand the opportunities and challenges of Ocean NETs, experts and representatives from the ocean business community and other stakeholders are invited to get engaged as speakers or participants in the SOS 2017 session on this critical issue by contacting the WOC at i...@oceancouncil.org <%20i...@oceancouncil.org>. [image: ***] *Practical Information:* [image: UpdatedProgram] <http://sable.madmimi.com/c/37127?id=2887543.2306.1.008c154ed2df0a79c61da7a08ac66441> [image: Date] <http://sable.madmimi.com/c/37127?id=2887543.2307.1.9080e62fa14a67d8c8852063d961a8fd> [image: Location] <http://sable.madmimi.com/c/37127?id=2887543.2308.1.e4865157bac7e41a14d6d6cd8143ca76> [image: sos] <http://sable.madmimi.com/c/37127?id=2887543.2309.1.c1127082dd4a8bb13cf24b6882e76e25> Stay informed of our latest news! 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