Ocean Acidification is a global-scale change in the basic chemistry of oceans that is under way now, as a direct result of the increased carbon dioxide in the atmosphere. We are just beginning to understand the impacts of Ocean Acidification on life in the ocean. The moniker “osteoporosis of the sea,” gives you a hint about some of its impacts. The basic chemistry of Ocean Acidification is well understood -- - not controversial. Here are three key concepts: First, the chemistry of the oceans is dependent upon the chemistry of the atmosphere. More carbon dioxide (carbon dioxide) in the atmosphere means more carbon dioxide in the ocean. Second, as carbon dioxide from the air is dissolved in the ocean, it makes the ocean more acidic. And third, the resulting changes in the chemistry of the oceans disrupt the ability of plants and animals in the sea to make shells and skeletons of calcium carbonate. And those chemical changes also dissolve shells already formed. Who in the in oceans is affected? Any plant or animal with a shell or skeleton made of calcium carbonate. The hard parts of many familiar animals such as oysters, clams, corals, lobster, crabs - such as the ones on this table are made of calcium carbonate. Many microscopic plants and animals at the base of the food chain also have calcium carbonate shells or skeletons. Some of these microscopic plants and animals are so abundant that when they die, their shells accumulate on the seafloor in massive deposits. The famed white cliffs of Dover are a familiar example of calcium carbonate - or chalk - deposits - the skeletons of microscopic organisms. Acidic ocean water is corrosive to all of these calcium carbonate shells and skeletons, but let me focus on two quick examples. First, Corals, which provide the fundamental structure for the world’s treasured coral reef ecosystems, make their skeletons with calcium carbonate. If ocean water is more acidic, it is harder for corals to make their hard parts. If the ocean becomes too acidic, coral reefs may well disappear. The second example is Pteropods - also called 'sea butterflies'- are small, shelled animals about the size of a lentil bean. They occur in the millions off the coast of my home state of Oregon, but also throughout the world's oceans. They are a key or the primary source of food for juvenile salmon and many other fish around the world. Pteropods are particularly susceptible to increasingly acidic ocean water, as you'll see in a moment. I mention them in part because they illustrate the broader consequences of a disruption to one part of an ocean ecosystem reverberating throughout the rest of the system, potentially affecting jobs, food security, tourism and more. Because pteropods are a main source of food for juvenile salmon, mackerel, pollock and herring, their demise will likely affect all of their predators, some in a major fashion. The severity of the impact of ocean acidification is likely to depend in part on the interaction of acidification with other environmental stresses, such as rising ocean temperatures, over-fishing and pollution from the land. Early evidence suggests that some species are better equipped to thrive in increased acidity, but the adaptability of most organisms to increasing acidity is unknown. While our understanding of ocean acidification’s impacts are still unfolding, the basic science of how the ocean is acidifying and the effect of increased acidity on some marine organisms is well-known. I would now like to demonstrate two of the basic concepts I mentioned earlier. The ocean does a great service by absorbing tremendous amounts of carbon dioxide from the atmosphere. In fact, the oceans have absorbed about one-third of the carbon dioxide that humans have added to the atmosphere over the last 2 centuries, greatly reducing the impact of this heat-trapping pollutant on the climate. But the carbon dioxide absorbed by the ocean changes the chemistry of the seawater, making it more acidic and corrosive. When carbon dioxide dissolves in water, it forms carbonic acid, making the water more acidic. I would now like to demonstrate two of the basic concepts I mentioned earlier. To illustrate how this occurs, I have a vessel of water that I will pour into this container and I have a common laboratory blue dye that changes color depending on the acidity of the solution which it is so let me put a few squirts of this blue dye into this tap water make it a nice blue color here one more squirt for good measure and I have some frozen carbon dioxide otherwise known as dry ice okay so this is ordinary water its blue color illustrating that it is neutral acidity as I drop in dry ice or carbon dioxide into the water the carbon dioxide changes to carbonic acid and that in turn changes the acidity of the water and so you can see graphically the blue changing to yellow illustrates that the water has become more acidic now I emphasize that this is tap water that we've used but the same principle holds true for the oceans if we make them, when they absorb more carbon dioxide that simply makes them more acidic but the second key concept that I want to emphasize is that the impact increasing acidity on shells made of calcium carbonate is a function of the level of acidity in the water so I have three glasses into the first one I will pour water into the second wind I will pour half water and half vinegar an into the third one I will pour vinegar so we have three beakers this is neutral acidity water this is more acidic because vinegar as you know is a weak acid and in this is more acidic so we have a gradient in acidity I will take sticks of chalk, calcium carbonate when I was growing up the chalk that we used in classrooms was pretty much pure calcium carbonate most chalk today is not completely calcium carbonate there are other things in it to make it less breakable and less dusty so if you try this at home you need to get the stuff that's mostly made of calcium carbonate we put it into water of neutral acidity and the chalk just sits there just like most shells in sea water are not affected by the water around them if however I put the chalk sticks into the beaker that has half water and half vinegar you can see bubbles beginning to form as the chalk begins to dissolve in the water those bubbles are carbon dioxide that is being formed as the calcium carbonate is dissolving and if I put the chalk into the vessel that is pure vinegar that dissolving of the calcium carbonate happens even faster now to be clear the ocean will never be as acidic as the vinegar we've used here I'm using vinegar just as a dramatization of the effects of ocean acidity because I only have a few minutes to demonstrate these basic concepts so increasing acidity makes the shells disslove faster and the water becomes more acidic as it absorbs carbon dioxide from the atmosphere but let's move from a chemical demonstration to a biological one to show you the effects of the projected increase in acidity in oceans worldwide I've brought a short one minute video clip before I start the clip let me describe what you'll see the first ten seconds will show a living swimming petropod or sea butterfly which I mentioned earlier about the size of a lentil bean, pteropods play a key role in ocean ecosystems in part as I mentioned because they provide food for juvenile salmon mackrel, pollack, and herring following the healthy pteropod in today's ocean you'll see if that happens to a pteropod in sea water by the end of this century if nothing is done to reduce the carbon emissions let's start the video here we see the normal healthy pteropod swimming the the ocean this is what it should look like and now we will see a pteropod shell that is in ocean water that's what we expect to be by the end of this century and as you can see with more days in this increasingly acidic ocean the shell is completely dissolved and animal would not be healthy this last clip is an animation illustrating from the year seventeen sixty five to twenty one hundred the effect that increasing ocean acidity on the availability of calcium carbonate mineral that pteropods, corals and other such organisms need to create their shells and skeletons the projections assume a business as usual emissions scenario a change in the color of the animation for purple to pollute a yellow to red indicates increasing ocean acidity and decreasing availability of a form of calcium carbonate needed for the formation of many shells and skeletons ocean acidity has increased by thirty percent since the beginning of the industrial revolution just over two hundred years ago this increase it's one hundred times faster that any change in acidity experienced by marine organisms for at least twenty million years by the middle of the century it is expected that coral calcification rates will decline by a third for an erosion of corals will outpace new growth making many coral reefs unsustainable and by the year twenty one hundred vast areas of the ocean ultimately shown here in red will have preached a level of a acidification where pteropods, corals, and other important marine species will likely be severely compromised by the increasingly corrosive nature of the sea water there Our understanding of the impacts of ocean acidification is relatively new. Roughly two thirds of the published research has come to light since 2004. Thanks to Congress’ action in passing the Federal Ocean Acidification Research and Monitoring Act, more attention will be given to this subject, particularly by scientists at NOAA and our partners at the National Science Foundation and in academia. Nonetheless, the fundamental scientific understanding of the basic chemistry of ocean acidification is sound. More carbon dioxide emitted into the atmosphere will lead to more carbon dioxide being absorbed into our oceans, and this in turn will result in increasing ocean acidity. Recent evidence suggests that the ocean’s very capacity to absorb carbon dioxide from the atmosphere may be slowing down, degraded by ocean acidification. These mechanisms can only be addressed by decreasing the amount of carbon dioxide that enters the atmosphere. The dramatic impacts that ocean acidification can and will have on ocean ecosystems are clear. And we can see, looking back, the dissolution of chalk in the most acidic water here how problematic that might be for many plants and animals that we depend upon