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You students here. Thank. You sir for coming out tonight on cold rain all the time we have current. Situation while ours. There are girls procedures. Everybody else is doing well it is true you don't really mean here's the Introduce much to your party every time it was if you swore by the numbers on the chairs or the answer is I'm just going.

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Believe. It Or Not last year we are going to. Go It's nice for trying to show you why it's so good for your body. It's. Very much for the very nice introduction and trade on or to give this present patient as a part of the series of talks on international hero periodic table so my name is tacky toe and I teach physical and chemical as shower feet.

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In the. School of Earth and Atmospheric Sciences at Georgia Tech so I'm very happy to talk about my favorite subject ocean chemistry today and here's just a brief are trying of my talk I'd like to start with a periodic table of fortune over for us to help us understand what's happening to the chemistry of the oceans so I want to transition to more of a changes that we observe in the ocean chemistry today in a 2nd part so let me just dive in.

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Book excuse me so. In the late 1990 s. you're Ntozake he knows Ickes sensei is a chemical arsenal referer from Japan and he took he put together a periodic table of elements dissolved in the seawater. And what's interesting is this diagram is that he in capture a bit the vertical profile of each element of the served.

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In the north Pacific Ocean for each element so there are as of $9090.00 s. there are already more than 80 elements measured in the seawater and each box here I'm sorry it's kind of hard to see but it's a vertical profile so this is a concentration and y. axis is depths from surface to 5 kilometers so the bottom of the ocean.

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And also he put together the different symbols so it indicates the overall amount of concentration and these data go into. More detail. In a few slides but these measure measurements come from the research crews on the ship and it's a lot of work to sample waters this is the water sampler and this is the winch that sends these some pros down.

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Through the water column and of when we are not eyes on board so this is a picture from several years ago when I was on this cruise and I was making a wink or a title ation to measure or excision so. A lot of work went into making these datasets.

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And. So not likely since are found several patterns in the distribution of elements in the ocean I box these. High concentration of immense here in the blue box so I highlighted them those are the ones that are dear to very high concentration higher than merely more of these elements politer of seawater in these a main ingredients of sea salt.

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You can see. Earth and somehow or Jens. Like karate. And so the Among them is you simply have some of these are main ingredients sort. There are some intermediate concentration and immense Not many nitrogen oxygen city force for us these are important marker nutrients in the ocean those are in the order of one a micro more per liter of sea water while higher and the rest trace elements are very low concentrations.

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On the order of not a more people probably 8 or. Those takes up the bark of the periodic table. And he also identified there are several Parton's of this vertical structure. Some elements are conservative we call a conservative the vertical profile is almost uniform vertical is so the concentration is about the same everywhere and.

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High concentration see so it's mostly following this pattern and some trace elements are so conservative This indicates that they don't really act very quickly. And so over the long time the ocean mix this and it tends to homogenise the concentration so we also color These are normally active elements.

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And eventually they will get into the settlement and they originated from the breakdown of rocks on the land it's called where the wing and the beaver run off of transport that elements in but these comedians of yours in the ocean so the ocean circulation has time to just completely almost completely homogenised them and that's gradients of sea salt.

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The front another group of elements that behaves different 3. Those are the ones that's high concentration near the surface and as you go down with Depp's the concentration decreases and these are called scavenged profile. And there are several of these trace elements. So it is a low minimum guineas and several others that has destroyed file and what they seem to indicate.

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Is. That they have a common mechanism to form these distributions so we think of these elements coming from the atmosphere their position of arrows all that comes and deposit those dust from the atmosphere and the that's the source. And enters in the ocean but these trace Meadows. Active to the particles so he sticks to the Marine particles that are present in the ocean and he sinks out so all the sources at the surface and then it's observed into a protocol in the subsurface it creates a pattern that's decreasing with Depp's.

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And then there are another type of elements the has the opposite pattern that low near the surface and it increases with Depp's and this is called nutrient like profile. In fact all of these marker nutrients nitrogen force for us silica these low or near the surface and it goes up with depths but so is many of the trace elements a knife still find a very interesting.

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The many trace elements are also behaving like nutrient. So the underlying mechanism that's shared with these elements. That we have active for the synthesis and production of organic matter in the surface or Sion and these living organism recurrence sume the nutrients because they use the nutrients from the water to build biomass So the surface water is depleted in nutrients and those organisms produce organic matter making particles does sink through the water column and as a sinks those particles decompose back into a organic form so he leases these elements back to the water so the biology is essentially taking up the nutrient from the surface and then sending it down in the same back to the water so all it creates this protocol profile that reached a depth and depleted at the surface we call this a new turn like profile.

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So. So that's obviously what dictates the major nutrients like nitrogen and phosphorous but it also affects many trace meto elements that I find very interesting but back in 1900 there were not many of survey sions of these trees elements this is. A diagram I took from this paper plane total would be 2 Southern 16 this is a.

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Number of dissolved iron measurements as a function of time so you can see back in 1990 s. we have only a few 100 of our measurement that was enough to produce a vertical profile like this I don't also has a profile like Nutri like but we have a lot more measurement in recent years so what's been happening in the last 20 years or so is that making these profiles of.

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Trace Meadows 3 dimensional So we have more structure that we now serve so this is. Sort of State of the earth of measurement of iron in the ocean from the Geo traces project. That's been going on in the last decade or so so what we see in this cutter shading is the concentration of dissolved iron in a sea water photo in the pathway of research cruises so these curtains of color shading is following the research crews and then it's prodding the concentration as a function of Depp's So we see sort of more 3 dimensional structure and so you can see that the nearest surface the blue or purple Carter is showing very low concentrations near the surface it's generally roll and it's in bridged depths always do see this profile but we also have a lot of horizontal structure.

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Such as these features high iron coming off of the mid or shine ridges and these are thought to come from these black smokers the hydrothermal vents are important source of dissolved Ion Now we document the in these data. And so we this is something that we work on in our group to moderate this iron distribution in the ocean we now think that the system is a lot more complex that we have multiple sources not just from the atmospheric dust deposition but also Iran may come from the sea for us sediments also hydrothermal vents and we know that there it's a it's an important nutrient so he has a.

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Signature of biological consumption of the surface and he sinks with the particles but also it's scavenged onto the particles us trace metal and also you forms Island big and complex in the water and these are complex c.-h. and is very important because these Ira league and complex are dissolved in the water and that is not scavenged on to the particles so it's maintains the senatorial structures so.

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We are continuing to run the mechanism behind these profiles. For trace Meadows. And I want to switch a little bit to the human impacts the costo you trophy cation. Here I'm talking about nitrogen. Sources coming from the land. Of nutrients from the fertilizer waste water tends to increase the nutrient levels of beavers in estuaries and this is a very important program because the higher level of nutrient causes our go brooms that produce toxins and it produces a lot of organic matter if decays it consumes oxygen and also produce localised to defeat cations So it's important cost of environmental program and this is a map of the nitrogen roading for the issuer of these are on the u.s. course so you can see the Mississippi River gets a lot of nutrients from their fertiliser use in the upstream and we also have a program in the media Atlantic coast.

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More from the waste waters from the population centers but most of the is juries have some degree of your trophy cation and. The mainly flex the new General Odierno though each issue is different. So this map shows sort of the overall your traffic condition that mostly mirrors the nutrient loading.

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And I want to talk a little bit about oxygen and oxygen is an interesting element here doesn't look like any other elements in the in the sense that this looks like more like a leavers of the nutrient profile. And yet this is very important for life. All marine life nice oxygen for metabolism and.

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Surface water is duty free in Ridge to because 20 percent of atmosphere is oxygen and exchange of gases between the ocean and up and sphere tends to keep the surface or a cross to such a ration with the atmosphere and the such ration concentration of oxygen is a strongly dependent on temperature so here's the temperature x. axis and such ration oxygen on the orange or I it's a decreasing function of temperature so the warm water pours less gases and the blue dots are individual measurements from the surface waters so it more slowly for those days saturation the Asian ship.

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In the subsurface oxygen level goes down because of the decomposition of organic matter. Where the surface oxygen is produced by before the sink that is any us into the atmosphere. While the organic matter that's left behind will sink into the interior ocean and as a sinks it decays back into their getting nutrients and carbon at the same time oxygen is consumed at death and so the biology is consuming the subsurface oxygen and that.

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Loss of oxygen has to be replenished by their physical psyche ration that's transporting the reality of record water from the high large to use physically transporting it so so in order to maintain that dynamic steady stay the loss of oxygen by the biological processes has to be balanced by the physical transfer of oxygen.

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By the ocean circulation so that kind of maintains this shape of the oxygen profile in the ocean and this is something that we spend a lot of time studying. We also think that the oxygen is changing in the ocean. Part of it is because of the fact that Austin is warming up and the warm water through the thermodynamic creation ship the number is not very important but normal warming of the ocean tends to lose oxygen over time.

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And the 2nd factor is also important that there when the ocean is heated it's heated by. The surface heated at the surface or ssion so it tends to increase the stratification of the ocean. That the surface water is warmer and less dense and that surface water is even getting warmer Why would the deep ocean leave main street every quarter so the density difference between the surface and that depth is increasing as the ocean is heated up and.

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We think that that's going to reduce the physical supply of oxygen into the interior option because the surface mixing convection at the surface has to get weaker as you increase the density contrasts between the surface and that that. So this 2nd effect. Is deity really less now so we have been asking how much oxygen change has happened in this instrument record of the ocean so we've looked at war Dawson database this is international project where data centers and individual laboratories subnet.

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Of the of Asian savation are data to this data set and as of 2 servants are teeing oxygen profiles there were about a little bit short of a 1000000 oxygen profiles so that makes oxygen the most frequent tree measured chemical element in the ocean following temperature and salinity of course so.

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We have looked at this dataset and developed us 3 dimensionally grid and time resolved dataset of oxygen and we carry to date the temp or a change of. Oxygen event 3 as a function of time so that's the upper left panel. This publisher and there goes doing this ups and down is oxygen in been trained up or some other meters Grover integrated.

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So there was a period of a little bit of increase before 1980 s. And then after eighty's we have this strong decrease so that's the pattern we. Find and the horizontal structures so if we take a linear trend at every great point and may come up we have a pattern like this this pattern is not complete in the sense that there are missed there is a lot of missing data especially in the southern hemisphere oceans away from the population centers but nonetheless we see.

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The more red or blue that means the red regions are the regions that oxygen is decreasing so we see North Pacific and some part of the tropical options losing oxygen also in the southern hemisphere high latitudes. Again the number is not so important but overall in the last 60 years or so approximately the options seem to of last about 2 percent of its oxygen content so that's a result from this study.

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We can also look at this indication to the rate that ocean is wearing up so this is sheet content. Of the ocean based on for us for this is a data set that developed. The e.c.m. dive you have a European Center for medium weather a medium range weather forecasting so we use their data set to carry could beat the heat content change so this is the general increase of heat content increase over the same time period.

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So we combine that together and make this diagram where the excerpt says is the heat content and the y. axis is the oxygen content and trying to look at the relationship as the ocean warms up we move to the right oxygen goes down so we have this downward spiral of being lying to the right here and each dots coming from the ridge to.

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Combination of oxygen and heat content. Saw approximately we have this slope is about 30. $32.00 micro more per kilo of thing that's the observed oxygen to temperature ratio and what we would expect from the family dynamic. Of the oxygen. Is is about this slope this blue line here so it's much shallower slope down is observed and indicates that about a quarter of the oxygen loss comes from the warming of the ocean and the rest so that is the 3 quarters coming from the north sort of a defect then we think that to some extent that has to be explained by the circulation changes or the changes in the biological processes.

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So under understanding this. How this works is still an open question. And I would also like to talk a little bit about carbon since this is also such an important. Element carbon has a. Nearly constant profile but also it is nutrient like because it's an important building block of living living organisms.

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So. What's interesting about carbon is that if you look at how much carbon carbon dioxide exists in the atmosphere it's about 800 grams of carb pin a gram is the 10 to the 15th. Grams of carbon. In the ocean we have above 40 Souder and so more than 90 percent of carbon.

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In the ocean atmosphere system is in the ocean and this is a Mark the mark of all size of they're all shown reserve of carbon. Is is due to the charge associated with the charge of balance of the ocean. Where we have a lot of these positively charged irons in the ocean and that's coming from this weathering of land in order medians of years or so in accumulated decease So it and if you.

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Look at the poor the charge electrical charge of these seesawed it's slightly biased towards the positive and that positive charge has to be balanced by these carbonate species so and we want to have a net neutral if you think of the electron balance of the ocean we have to have a net neutral so we have to have a lot of these carbonate species to balance that charges from the positive charges from the salt.

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And. In the Barossa Cup process is also utilize the carbon sending to the portions of these kind of explains the vertical vertically in reached profile. And that's for other enriching the deep ocean carbon reservoir. So what's happening is that we're adding more and more c o 2 into the atmosphere we're adding this c o 2 into the atmosphere and that goes into the ocean the main reaction is that the c o 2 goes into the ocean and it combines.

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With carbon. And water molecules to form by carbonate and the by carbonate the h c was 3 minus is the major carbon species in the ocean about 90 percent of carbon in the ocean is in the by carbon and 10 percent is the current pool but in any case the ratio between these 2 guys is actually what's determining the ph of the seawater so as we increase more and more c o 2 this reaction shifts to the right and we're increasing the by a carbon it at the expense of consuming current So over time the hydrogen ion concentrations acidity of the water is going up.

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So this is the. Market mix like here. So this is the turning sour of part that. In the last decade or so on average. The International c o 2 emission is on the order of $9.00 Prosser minus a half paragraph of column per year out of this about less than half is remains in the atmosphere that contributes to the rise of the atmosphere Ixia to about half is disappearing from the other as fear about quarter goes into the ocean in the another quarter of course into the land so option is doing a great service in terms of slowing down the buildup of c o 2 in the atmosphere but because of the reasons we saw in the previous slide the ph ph of the seawater is the creasing and acidity of the water is going up so so so far since the Industrial Revolution we have seen about.

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A 30 percent increase in the hydrogen concentration and that's a substantial increase. So. Tours are coming close to the end and I wanted to talk a little bit about the ecological impacts that rate of change of these ph is. $10200.00 times faster than any period in the last 50 mirin years of the Earth's history so this is literally unprecedented rate of change of the Earth's environment and the p. h. is important for the stability of kerosene carbonate that is important and I share or scared on material for living organisms and the shelf is specially the early young stage is known to be runnable for the acidification So this is.

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The ocean is becoming more and concerned for fishery and ecosystem but I want to end with a little positive outlook on this story. There was a really interesting story from the Pacific Northwest shellfish industry its $270000000.00 industry supporting more than 3 Southern families in the rural parts of northern California Oregon and Washington caused and what happens in 2 southern 7 was that there was a near collapse of oysters that produces oysters sees for the oyster growers in the region this happened in Oregon coast and.

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The operators are looking for reasons 1st they doubt it for Argo brooms in the production of toxins I doubt it cause of mass mortality the mortality was more than 80 percent. And in a few years they started to corroborate with scientists from the Oregon State University and know what pm e.-l. they determining that the actual cause of the mortality was the higher a city of the water so in within the few years they actually developed under a adaption strategy to mitigate the effect of these acidification this is microscopic image of.

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The oyster larvae which the seas. One day to day 4 days after the nation of the egg and at the early stage. As they develop their shells this is under normal condition this is high c o 2 they demonstrated that the c o 2 has a major effect on.

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The development of these disease. But the amazing aspect of this story was that they reacted so quickly and developed a scientifically based solution to this program day. This diagram is showing that the what's Leary important in this program was actually the saturation State of Iraq that's a certain form of care to cover a mineral and they determined that that city ate it to.

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The production rate of the Seas which is the y. axis and found the syringe showed $1.00 in this unit is going to be the stress showed for commercially viable operation of the heart Sherry So they developed the earlier time morning tearing of the water quality and they only used the water.

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Open the water intake and the water condition that is good. And also David it developed the buffer ph buffering system to sodium carbonate into the tank when the ph was too low so so I think this is a very positive story that signed science and the fishery community work together to develop the solution so this is my last slide.

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I hope. That I was able to convey some of that understanding behind these current ongoing changes of the or ongoing changes in the ocean chemistry. And the importance of taking actions are can Orage the problem and also. I think developing there is a resilience. And science based solution opens up.

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New sets of scientific and engineering questions and opportunities so with that I'd like to finish my food. Patient thank you very much for your attention thanks. So much for the time. And the. Current us. As. Well. I think so the question was So what would be the consequence of collapsing or if if they're trying to clear their overturning circulation what a collapse what would be the consequence.

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Nutrients oxygen. Ecosystem I think that's very important questions and actually we are I think we have something to say we have work we're working on these programs because there is a more there projections that as the warming continues. That overturning might weaken we think it's an important transport pus way of nutrients to the north Atlantic Ocean.

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And they is a term called nutrient stream. And actually dinner Rosie is one of the pioneers who developed this concept so. We think that as if if it weakens it will reduce the surprise of nutrients to the north Atlantic Ocean so it creates use the. Potential to potentially reduce the productivity by a significant amount what that does to oxygen is interesting because of the weak and biological productivity there be arrests production of organic matter so.

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And the sinking organic matter is a major sink of oxygen so you might end up having a less oxygen loss because of having. Less organic matter production so that's. That's a hypothesis at the moment. But I think there would be a far reaching inference. Or. Right so the.

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The question of 40 lies in the ocean. Potentially as a way to. Mitigate program with c o 2 because increase the ocean productivity that is suck up the c o 2 from the atmosphere. So I think the has been that idea has been. Around for quite some time and also people have conducted in situ and also more than any experiments so my understanding is that it does increase biological productivity locally.

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However the effect on the carbon uptake part is not so clear and the reason is being now at. I think one reason is called the downstream effect that locally produced of the biological carbon up tick but if you consume. Other nutrients in that region and up my end up productivity being decreasing in the downstream region so as a whole.

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System you may not. Be as effective. So. I think there are several ideas that that counters the the idea of Asian. But I think there are there may be still. People thinking about that possibility. Right here show. Station readings here. Let me see. So I can see. Something to.

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See which was a huge. Interest. It's pretty controversy. And. That's that increases you. So. Much. As went. Thank you. Those. Are. 2. Kinds. Of us whose. Current. And. This. Strange. Climate for the news. So the question of a calcium carbonate production and sending it down to the sea for a sediment is actually a very interesting program but actually it would end up increasing the atmospheric c o 2.

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Because of it is being calcium carbonate. It is a it is denser So it's it's easier to sink for sure but what happens is that when you form cancer and covered it you're taking away calcium iron from the water combine it with carbon. To make your sim carbon and then they're both exported to the sea floor and that has different effect than making organic carbon and sending it to the deep ocean and the difference is that calcium carbonate has calcium iron and calcium ion is positive positively charged so you take away.

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That calcium 2 plus from the surface ocean and end up making the surface water more acidic. Even though you're removing carbon you're leaving more calcium iron and salt from the surface ocean so your so-called alkalinity level is decreasing more than you decrease car so it is known to actually increase the atmospherics year 2 so the parts that are important for drawing down our atmosphere exceed 2 is the organic part that's the part that we want to do to be stronger if you're if you think you have the lowering c o 2 in the atmosphere.

[00:43:04]
If you really. Soon there's. So this road to Mars. Work Orders. Which. Means. You know you know what. There's. No. Sir course and this is very hard. Yes. Or. One more missions. For you to. Use so of course. Is there. Yes I definitely agree with your comments that that has to be the future and for oxygen nitrate Ph.

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And a few other things we do have a solution that is autonomous and so those robotic frauds that can be released and be operational for years and making hundreds of profiles for lifecycle are now available and deployed in certain regions of the ocean not good over the yet but I am leary hoping that we have.

[00:45:13]
The global coverage of those autonomous census director increase the amount of data by orders of magnitude yes I definitely agree. This year's much. Well so predicts Shane is difficult. However and. We can use one ways to use more those. We have the building assumptions but there are more there base pretty projections really under different scenarios we can project how much c o 2 is going to be there in the atmosphere then we can cap we can carry cure rate.

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What would be the projected ph level going to be ph is probably easier to predict because it's strong related to the c o 2 levels so we can do based on. The mechanistic more there are base projection and that's probably the best horse we have because of the question.

[00:47:25]
I was. Wondering. Thank you very much for the question I know very familiar with. This that particular. So but. It's the question is Georgia is not enough fresh water right. I am getting interested in this program but I and the moment I don't. Have much information that I can offer and Fred.

[00:48:38]
I'm going to experience. So. If you're. Our Thank you very much thank.