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Scientist Talks about the Once and Future Ocean


Aired 4/20/09

What role do the oceans play in sustaining life on Earth? How have humans altered the oceans and will they, and us, survive? We'll talk with ocean expert Paul Falkowski about the once and future oceans.

MAUREEN CAVANAUGH (Host): I'm Maureen Cavanaugh. You're listening to These Days on KPBS. Here in San Diego we see the ocean as a place of recreation, or as a gorgeous view. It's something always present, always beautiful, always part of the definition of being a San Diegan. In a much larger sense, the earth's ocean is part of the definition of life itself. Many evolutionary biologists believe life on earth began in the deep ocean. The relatively brief history of humans is intimately tied to the health and abundance of the ocean, and my guest this morning reminds us that our future is tied to it as well. The earth's ocean is changing. Many scientists believe human activity is responsible for that. Professor Paul Falkowski says if the changes cause a significant erosion in the ocean’s current ecosystem, it’s human beings and not the vast ocean that will suffer. Paul Falkowski is newly appointed adjunct professor of Biology at Scripps Institution of Oceanography at UCSD and is professor of biochemistry and biophysics at the Institute of Marine and Coastal Science at Rutgers University. Paul, welcome to These Days.

PAUL FALKOWSKI (Professor of Biology, Scripps Institution of Oceanography, University of California San Diego): Thank you very much, Maureen. Thank you for having me.

CAVANAUGH: Well, give us, if you could, a brief history of the ocean. How old is it. What did it first look like?

FALKOWSKI: So we know the ocean is approximately 4 billion years old at least. The rock record is much more difficult to use to try to really show when the oceans first occurred but the earth is about 4.5 billion years old. We know that for sure. And as soon as we can see the signs of water, it’s about 4 billion years old. So the oceans have been on part of this planet for a very, very, very long time.

CAVANAUGH: Did they look anything like the ocean we know today when they first formed?

FALKOWSKI: No. The oceans in the early portion of earth’s history, for about the first two and a half billion years of earth’s history, had no oxygen. There were no animals in the ocean. Everything was microbial. That means there were very, very small cells, invisible to the naked eye. And the oceans in those periods of earth’s history were probably less salty and had high, high concentrations of carbon dioxide in them. And were very, very warm.

CAVANAUGH: Now the ocean has gone through a number of changes as we’ve gone through the 4 billion years you talk about.


CAVANAUGH: What are some of those key points that, as a professor of oceanography you look at when you look in the distant past. How did those – How did the ocean change significantly?

FALKOWSKI: Well, the major turning point was about 2.3 billion years ago when we see evidence of oxygen on earth. And all the oxygen in the atmosphere that we breathe is derived from the ocean. It’s from the splitting of the water molecules into the component parts of hydrogen and oxygen, and the hydrogen is going to make carbon dioxide into organic matter. That’s the food of life. So this process, what we call oxygenic photosynthesis, or photosynthesis that was – commonly we see in green plants everywhere, evolved first in the ocean. When it evolved exactly we’re not sure but once it evolved, it generated oxygen which created the potential for all animal life subsequently. Now shortly after the evolution of oxygen, the oceans became covered with ice completely, even down to the equator. And it appears that we’ve had either four what’s called snowball or slushball periods of earth’s oceans like that, which were 7 million – several million years in duration. And each of those periods of earth’s history still allowed life to carry on in the ocean. The ocean really is the giver of life to the planet. It is the ultimate reservoir of all of the genetic information for life that evolve later on on land.

CAVANAUGH: And as the ocean has changed, do we know how these changes have come about and why it was covered with ice, why it had these slush periods?

FALKOWSKI: Well, there are many theories as to what were the major causes of these so-called snowball events. One of the early ideas, and I think it’s a very viable one, is that there was a lot of methane on the planet early on in earth’s history. And once you create oxygen, the methane becomes oxidized to CO2. Now CO2 is a greenhouse gas as is methane but CO2 is a much weaker greenhouse gas so when you convert methane to CO2, the atmosphere is not as warming as it would have been previously and the earth got very cold.

CAVANAUGH: Very cold, I see.

FALKOWSKI: And we don’t understand how this occurred, though, four times. So the geological record gives us clues but we’re still working on this quite a lot through proxies of isotopes of carbon and so on. It’s a complicated business.

CAVANAUGH: Well, about 200,000 years ago, humans come on the scene. How big an influence have humans been on altering the ocean?

FALKOWSKI: Until recently, trivial. Human beings have a very interesting history. They evolved in a very uncertain way from the great apes about six billion years ago – I mean, six million years ago. And only about 200,000 years ago do homo sapiens, our species, appear to occur on the fossil record. And we have a set of genes which is unique to animals and those genes give us the ability to speak and transfer information laterally across vast reaches of the universe like I’m doing right now on this radio station. So I’m transferring information horizontally without transferring genes, and that allows people then to have collective knowledge of how to do things. And over the last couple of hundred years, that collective knowledge has been rapidly accelerating the pace of human reach and global plunder of resources. So, whereas 150 or 200 years ago our ability to extract oil or coal or natural gas from the environment was very small, today it’s extraordinarily rapid. We can extract in one year one million years worth of deposition of natural resources from – in fossil fuels. So we’re a million times more efficient in extracting resources than nature was in putting them there. The consequences of this are in the last 100, 150 years we’ve altered many of the cycles on this planet, the carbon cycle, nitrogen cycle, phosphorus cycle, water cycle and so on. So human beings have greatly, greatly changed the planetary conditions and as a result of that, we are seeing direct and indirect effects on the ocean. The direct affect is acidification. The indirect affect is changes in ocean circulation.

CAVANAUGH: Is acidification your – the major concern about what the oceans are facing today?

FALKOWSKI: They’re both of major concerns but acidification is a really difficult thing to undo. Once it’s set in motion, it’s like a huge rock rolling down a hill. It’s very difficult to take carbon dioxide out of the atmosphere, very, very expensive. It’s not impossible but it’s very expensive. And the acidification will make it very difficult for organisms like corals and other organisms that produce calcium carbonate shells to survive for the next few hundred years of the ocean history. They will not go extinct but there’s going to be an incredible preening, weaning loss of diversity of these organisms.

CAVANAUGH: Now how does carbon dioxide in the air cause the ocean to become more acidic?

FALKOWSKI: Carbon dioxide is a strange gas. It combines with water to form a weak acid called carbonic acid and that you all know as seltzer water, basically. Okay, so when you open up a bottle of seltzer water, there’s – CO2 is mixed in with the water at the factory and the pH of that is acidic. Seltzer water is a little acidic. If you were to take the seltzer water and pour it onto a marble tabletop day in and day out, you would erode the marble tabletop. You would take – the carbon dioxide would slowly erode the carbon – carbonates of the marble, and that’s exactly what is happening on a longterm global scale when we add more CO2 to the atmosphere.

CAVANAUGH: I’m speaking with Professor Paul Falkowski, and we are talking about the ocean and the way that human activity has changed the ocean in the last 100 years or so. You know, Professor, we hear about the dead zones in the ocean and how these dead zones are now being charted and they’re kind of close to the coast. What causes the dead zones and what are they?

FALKOWSKI: So these are places where there’s very little or no oxygen and they’re caused in two – by two different processes. In the Gulf of Mexico, for example, they’re caused by runoff of huge amounts of nutrients that are put down by farmers, primarily, and homeowners and golf courses when they want to fertilize plants. And as a result of rain, you get all these nutrients into the Mississippi River, it runs down into the Gulf of Mexico and it causes huge blooms of microscopic plants called phytoplankton and those plants then ultimately die and decay and they remove the oxygen from the waters and cause death of that environment of fishes. In the Pacific northwest, we see the changes in ocean circulation have caused huge differences in the amount of what’s called upwelling, which is to bring the nutrient-rich waters into the surface along the coast, for example, of Oregon and Washington. And that is a process, again, that’s an indirect effect that causes huge anoxia along the coastline of the west of the United States leading to, again, dead zones. So these are two processes driven, one directly, one indirectly, by human beings.

CAVANAUGH: And the ocean so vast, it’s hard to think of puny little humans being able to significantly alter it. And you’ve already explained that it’s gone through such changes in the past, is it possible that the ocean may be able to recuperate on its own?

FALKOWSKI: Absolutely. The ocean will outlive humans easily. I mean, microbes are the stewards of the planet, not human beings. We’re very bad stewards so far. Microbial organisms, those tiny, invisible organisms that I first described that were evolved 2.5 more billion years ago, have been, throughout all of earth’s history, the major stewards of our planet and they’ll do fine. There’ll be many animals that may go extinct in the coming few hundred years of earth’s history primarily as a result of human interventions but at the end of the day, if we’re going to have 9.5 billion people on this planet, which we expect will be the number by the middle of this century, we are going to have to be much better stewards of our own resources.


FALKOWSKI: We’re the fragile species.

CAVANAUGH: …we’re the fragile ones so it’s to our own benefit but what is it that we do? What can we do?

FALKOWSKI: Well, I think the concept of sustainable resource development is absolutely critical here, and it is something that is starting to make its way through the circles in Washington. It is still anathema to many economists. There is a concept of moral economics, which is starting to emerge but the idea that we can just continue to plunder the planet and extract resources and there will always be a solution to whatever we remove, is not compatible with the reality of the biology and physics and chemistry of what this planet is endowed with. So, in a – for instance, energy is a major, major concern right now. We can rapidly develop, over the next 20 to 30 years, sustainable, renewable energy resources that will provide the electricity and power for our automobiles that will generate basically no carbon and would be totally green. It’s just a matter of will and a matter of economics, and so the economic stimulus has to be there to produce that, otherwise carbon dioxide concentrations will rise much, much, much faster and we’ll just reach a point in which human beings will be suffering far more.

CAVANAUGH: Just a quick last question to you. I wonder as we celebrate Earth Day, do you think more attention should be paid to the ocean?

FALKOWSKI: I think the ocean should be respected far more than it is. We don’t anymore have a spokesman for the ocean. The ocean doesn’t vote. There’s no constituency. So from a political point of view, the ocean is invisible. With Professor Jane Lubchenco now at NOAA, with many of my colleagues now working in this administration and very conscientiously trying to figure out how to extract us from the road we’ve gone down and put us on a new road towards green and sustainable economic growth of the country and the world, I think there’s hope. And…

CAVANAUGH: Well, I want to tell everyone if people want to hear more about the ocean and from Professor Paul Falkowski, you can hear his lecture "The Once and Future Ocean" today, 4:30 p.m. at the Scripps Institution of Oceanography in La Jolla. The event is free, open to the public, and if you want more information on it, you can always go to Paul, thank you so much for being here.

FALKOWSKI: Thank you very much, Maureen.

CAVANAUGH: Stay with us as These Days continues in just a moment.

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