Ocean acidification -- the ongoing decrease in the pH of the Earth's ocean caused by increasing carbon dioxide in the atmosphere)--may be a bigger problem than any of us realize!
Fortunately for us, we have the National Oceanic and Atmospheric Administration's (NOAA) Pacific Marine Environmental Laboratory (PMEL) on our side. Scientists at PMEL carry out many types of investigations in the ocean and atmosphere.
One program was of particular interest to us. The Carbon Dioxide (CO2) program at PMEL, located in Seattle, Washington, researches the ocean carbon cycle in most major ocean basins. Of course, that also includes the ocean's acidity level--a.k.a. ocean acidification.
Oceanographer Simone Alin is part of the PMEL CO2 group. Her research focuses on how carbon dioxide dynamics affect coastal ecosystems, however she is also interested in how ecosystems are affected by issues like climate change and pollution.
We wanted to find out more about PMEL, their goals, the results of their research, and what they say about ocean acidification (after all, they devote a whole page on their site to it.) We had ocean acidification on the brain and knew Simone would be the perfect person to talk to about it.
What is the PMEL Ocean Acidification group?
Until recently, our group has been known as the Marine Carbon or CO2 group at PMEL, but with the upsurge in research interest and activity in ocean acidification, our name may be undergoing a transition. We are a group of 14 scientists at the U.S. National Oceanic and Atmospheric Administration (NOAA) who study the marine carbon cycle, which is made up of both organic and inorganic forms of carbon. The inorganic part of the marine carbon cycle is what needs to be measured to characterize ocean acidification conditions.
Specifically, we are interested in determining a few key parameters, like the saturation of aragonite and calcite in seawater, which are the mineral forms of carbonate that many marine (and freshwater) organisms make their shells or skeletons out of, or pH, which is a measure of the acidity of seawater. Seawater with high carbon dioxide (CO2) and low pH (= high acidity) can be corrosive to organisms with carbonate body parts and can also be physiologically challenging in other ways to organisms.
Our group collects several types of carbon measurements throughout the world’s oceans. For instance, we participate in and occasionally one of us leads large-scale research cruises across ocean basins or along coastlines at regular intervals (e.g. every few years to a decade or so) to study how ocean chemistry is changing through time, with particular interest in understanding how much of the carbon dioxide (CO2) emitted by human activities is taken up by the ocean and what effects this may have on the marine ecosystem. Absorption of CO2 by the ocean slows down the accumulation of CO2 in the atmosphere and thus has the effect of slowing down climate change related to the buildup of greenhouse gases in the atmosphere, but it also lowers the pH of seawater, increasing the acidity and lowering the saturation state of the biominerals, aragonite and calcite.
To be sure that I am clear, I should tell you that we do the carbon chemistry measurements, and we collaborate with biologists in other divisions of NOAA, academia, and other state and federal agencies to help them learn about the impacts of ocean acidification on ecosystems—we do not study the organisms ourselves.
We also do measurements of the concentration of CO2 (partial pressure [pCO2] is a more accurate term for it) in surface water of the world’s oceans using automated analytical systems that we install on both moorings and “underway” platforms, which is just our way of saying research and commercial ships. Soon we will be adding pH and/or other inorganic carbon measurements to our existing moored and underway systems to do what is needed to more accurately and precisely study the changes associated with ocean acidification. The inorganic carbon system has four parameters that can be measured: pH, pCO2, dissolved inorganic carbon, and alkalinity. From measuring any two of these, we can calculate the rest, in addition to the aragonite and calcite saturation states. What is your role specifically in the group?
Within our group, three of us are “principal investigators” (or PIs) (myself, Richard Feely [who is the overall leader of our group], and Christopher Sabine). As PIs, we are responsible for bringing in the funding to do our research (through proposals to various agencies including NOAA), writing peer-reviewed papers to get the results of our research out to the broader community, attending national and international scientific meetings and workshops to discuss our science, developing new ways to measure and monitor ocean chemistry, and working with people at NOAA headquarters to develop plans for scientific activities or new initiatives. All of us also participate in national and international groups that help to coordinate and synthesize what we know about marine carbon and OA across the global oceans. My specific role in the group is to lead these activities for our coastal program, as well as the “underway” measurement program that I described earlier.
How would the group explain the meaning of Ocean Acidification and its negative impact on our oceans, perhaps for the average person?
Ocean acidification (OA) is the term we use to describe the process through which the excess carbon dioxide that is in the atmosphere due to human activities (burning fossil fuels, deforestation, etc.) is taken up by the ocean, thereby increasing the acidity of the ocean. When carbon dioxide is absorbed in water, it forms carbonic acid (CO2 + H2O => H2CO3). All organisms have a range of environmental conditions that allow them to survive. For aquatic organisms, the acidity of the environment is a critical one, and the pH system is how scientists measure and describe the acidity of an environment. pH is expressed on a logarithmic scale for the concentration of the hydrogen ion (H+), which is what gives a liquid its acidity, so each pH unit (e.g. between 7 and 8) corresponds to an order of magnitude change in concentration of H+ (from 10^-7 to 10^-8 mol/kg-seawater, for our example). One thing that often confuses people when we talk about ocean acidification is that pH values under 7 are considered “acidic,” while those above 7 are considered “basic.”
Ocean acidification just means that the water is moving toward being more acidic, whether it starts above or below a pH of 7 initially. I think that people are accustomed to hearing about pH (we hear about pH-balanced shampoos, etc., in commercials), so it seems familiar, but I doubt that most people think about what pH means for organisms. Sure, if we have a very strong acid, people may understand that they will get burned by exposure to it, but with more subtle variations in pH, it may not be as obvious to “the average person” what the significance of changing acidity may be to an organism. Some organisms may be directly affected by the change in H+ concentration, because individual cells may regulate the concentration of different ions, including H+, on a molecular level to accomplish different physiological tasks (e.g. intercellular communication, osmoregulation, etc.).
Other organisms are likely more directly affected by the change in CO2 concentration that causes the changes in acidity. For instance, seagrasses take up CO2 during photosynthesis, and it seems that more CO2 makes them more productive, so they are essentially fertilized by more CO2. Yet other organisms are probably affected by changes in the concentration of carbonate ion (CO32-) that accompany the CO2 and pH changes (through a series of chemical reactions, when carbonic acid goes up, carbonate ion goes down). Organisms that build carbonate shells or skeletons may have a harder time doing so with less carbonate ion in the environment.
How is marine life specifically being affected?
At this time, there have been dozens of studies that have demonstrated deleterious effects of increased CO2 (and the lowered pH and saturation states that go along with it) in laboratory studies. For instance, the delicate carbonate shells of small swimming molluscs called pteropods have been observed to dissolve while they are still alive in waters with elevated CO2 levels close to those expected within the next century. In another study that was conducted in the field, researchers at the Great Barrier Reef of Australia have measured the rates of coral calcification (in other words the rate at which corals are able to build their aragonite skeletons) over the last few decades (i.e. at CO2 levels already in the ocean) and have seen a ~14% decrease in the calcification rate over that interval.
In the Pacific Northwest, the oyster industry has had severe problems with failed recruitment for four of the last five years that seem to be correlated to low pH conditions, according to measurements that they have made. However, there are several problems that prevent us from being able to say that all these problems are just due to ocean acidification. First, the change in pH associated with the uptake of anthropogenic CO2 from the atmosphere is a very gradual process – the pH can be expected to change about 0.001 units per year, and most sensors are not precise enough to measure a change of this magnitude so we don’t really have the data records for most places to correlate to the observed biological changes.
In addition, the natural variability of pH in an environment can be orders of magnitude larger than this (perhaps 0.5 pH units across the seasonal cycle or 0.2 across a 24-hour period), depending on other biological, chemical and physical processes that are operating in the environment in question. Because of the many other, simultaneously occurring processes that change pH, it takes long time-series of data to sort out what the role of natural variability may be in an ecosystem and to detect a long-term trend associated with human CO2 emissions.
Second, many of the laboratory studies that have been done may not have had consistent methods with other studies, so it makes it difficult to compare the results across studies and generalize about effects in different organisms (or in the case of one species, even to be sure about the effects in a single species where the outcomes of different experiments were different). Some species do seem to benefit from higher pCO2 (e.g. seagrasses as noted above), whereas others may be harmed, so we expect that there will be winners and losers. Scientists are currently in the process of agreeing on the best methods to use for OA studies to make sure that future studies are as informative and accurate as possible.
Third, it is difficult to know what the effects of ocean acidification will be in the wild because many marine organisms are likely to be exposed to harmful conditions some of the time already, due to the strong natural variability in their environments. The duration of the exposure may also be important, as well as interactions with other species. These types of studies have only recently begun. To sum up, in the marine carbon science community, we have a lot of concerns about what may happen in the future (or may have already happened) to marine ecosystems because of the impacts of ocean acidification, but it is difficult to say with a high degree of scientific certainty right now what will happen (or has happened) because we do not have enough information yet.
What is the PMEL group doing in order to remedy this problem?
The PMEL OA group is working to try to get funding for and to implement high-quality observational systems that will allow us to learn more about the development/progression of ocean acidification throughout the world’s oceans, but with a particular focus on the Pacific Ocean. Because of the way that circulation works throughout the global oceans, water in the North Pacific Ocean already generally has lower biomineral saturation states and pH values than other basins, so ecosystems here are likely to be more vulnerable to and show the effects of ocean acidification earlier.
We are also working with biologists at other institutions (as described above) to help them do the appropriate carbon chemistry measurements with the necessary accuracy and precision so that their results will be as meaningful as possible. Because of the recent passage of the FOARAM Act, we are also currently busy helping the agency to plan for national and regional OA monitoring and research activities, but it would be premature to comment on what these will look like because we are in the early stages of the planning process and nothing has been set in stone (note that this is part of the reason why it has taken me so long to answer your questions!).
I would also like to mention that we work closely with our sister carbon chemistry group in Miami (at AOML) – they lead NOAA’s Atlantic and Caribbean ocean acidification work.
What are the goals of the group?
The previous question kind of addresses this. Perhaps in a more general sense, our overarching goal could be described as making the highest quality marine carbon measurements possible (through contributions to field observation campaigns and technology development) in order to continue to improve our understanding of the roles of both natural and anthropogenic processes on the marine carbon cycle in the context of significant environmental change. Can you identify some of the legislation and projects the group has brought to the table to help combat the issue?
Although it is not within the scope of our work to bring legislation to the table per se, my colleagues, Richard Feely and Christopher Sabine in the PMEL OA group, along with other leading scientists in the OA community, have testified before Congressional committees on the scientific basis for our understanding of ocean acidification. The information given to Congress through these testimonials was used in the process of writing and discussing the 2009 FOARAM Act that you ask about below.
As for a specific project our group has done on ocean acidification, in May-June 2007 (shortly before I joined the group), the PMEL OA group led a cruise along the North American Pacific Coast from British Columbia, Canada, to Baja California, Mexico. During this cruise, the scientists (i.e. Feely, Sabine, and our colleagues from other institutions in the U.S., Canada, and Mexico) discovered that corrosive water that could be harmful to organisms was already upwelling along the Pacific continental margin. Based on models for the open ocean, from which OA forecasts were extrapolated to the coasts, these conditions were not expected to occur for at least a few more decades, so this was a surprising finding.
What is the Federal Ocean Acidification Research and Monitoring Act (FOARAM)?
The 2009 FOARAM Act authorizes Congress to allocate funding for ocean acidification research and monitoring activities in the U.S. The money would be given to NOAA and the National Science Foundation (NSF) to carry out these activities. The money has not yet been allocated. Given the new administration, we are optimistic that the funds will be allocated, starting in the 2010 fiscal year, but I don’t believe that this is 100% certain yet, as the process is on-going.
What can the average marine enthusiast or marine conservationist due to spread awareness of the threat of ocean acidification?
The average marine enthusiast/conservationist can start by informing herself/himself about the basic science behind OA through the various documents/sites that are available on the web. People have a lot of questions about how this works and what we can expect, so if marine enthusiasts are able to answer these general questions, I think they will find a lot of curious conversationalists around them. For instance, over dinner at the airport tonight, I talked for half an hour or so with the man at the next table, who happened to also be a scientist (in the pharmaceutical industry), but I think was more interested in this issue from the perspective of what it means for his kids’ generation.
I think the next step to spreading awareness and engagement is to find out what is going on within one’s own region with respect to OA. People are more engaged by issues that they can relate to near home (e.g. the coral reef I like to dive on every weekend is growing more slowly than it did when I was a kid, or the oysters I like to collect at my beach cabin no longer seem to be reproducing successfully, etc.).
Finally, the marine enthusiast/conservationist may want to try to educate one’s political representatives as well. All politicians have their own issues that are most important to them, so some may not have a good understanding of or interest in the problem of ocean acidification. What many may not have thought about is the incredible economic and societal impact that ocean acidification could have, so you could look into what this issue means for your region.
Ocean acidification is different from climate change in the sense that the chemistry is pretty straightforward, so we know that the pH and saturation states of the oceans will continue to decrease as the atmospheric CO2 continues to increase and get absorbed into the oceans. This part is not uncertain. What is uncertain is whether the oceans will continue to absorb CO2 at the same rate as they have and what the associated changes in ocean chemistry will mean for ocean ecosystems. That is a gamble that I think many would agree it is unwise to take.
Does the future look bleak for the world’s oceans thanks to ocean acidification?
This is hard to answer. Like I said earlier, we anticipate that there will be winners and losers in the ultimate outcomes of ocean acidification. We can be pretty certain that ocean ecosystems will change, but we do not know what they will look like in the future. We hope that there won’t be any big surprises or catastrophic effects, but we certainly cannot state with confidence that there will not be (just like we cannot state with confidence what changes there will be). What we are starting to learn, however, is that a lot of the other environmental changes caused by humans that affect marine ecosystems (e.g. pollution, habitat destruction, etc.) may act synergistically to increase the damage caused by OA to organisms and ecosystems.
While signs are encouraging that our society may start to reduce fossil fuel emissions in the near future, it will be a long time until we have the situation under control. We do know that the impacts of ocean acidification (and climate change) that accrue in the interim can be expected to last for many human generations. Between now and the time we are able to convert to a largely clean energy society, we won’t really be able to control OA and warming. However, in the meantime, it would be very beneficial if we could reduce other impacts that may exacerbate the impacts of OA on marine ecosystems. This is another way in which marine enthusiasts could potentially contribute to helping mitigate OA impacts – i.e. by informing fellow citizens and politicians alike about the problem of multiple stressors on organisms and ecosystems.
Problems that can be addressed on local to regional scales may be “fixable” on shorter timescales, which may give marine ecosystems a reprieve from OA and give scientists, engineers, politicians, and citizens the time needed to come up with a longer-term solution for the ocean acidification problem.
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