Posted by: chrismaser | March 21, 2012

OCEANS IN CRISIS—ACIDIFICATION

Although it is today common knowledge that anthropogenically-produced carbon dioxide is continuing to increase from such sources as coal-fired plants, industrial manufacturing, automobiles, and agriculture the political approach to the problem is symptomatic, rather than systemic. In other words, alleviate a symptom, but under no circumstance deal with the cause because it would demand a radical shift in our thinking, which in turn would disrupt economic interests. One such symptomatic approach, touted as the “energy panacea” to our US dependency on oil, is corn as a biofuel.

CORN AS BIOFUEL

To fully understand the ramifications of corn as a biofuel, we must first understand something about corn as a crop. Author Richard Manning has the following to say about the importance of corn:

If you follow the energy, eventually you will end up in a field somewhere. Humans engage in a dizzying array of artifice and industry. Nonetheless, more than two thirds of humanity’s cut of primary productivity [the amount of green vegetation produced in a particular year] results from agriculture, two thirds of which in turn consists of three plants: rice, wheat, and corn. In the ten thousand years since humans domesticated these grains, their status has remained undiminished, most likely because they are able to store solar energy in uniquely dense, transportable bundles of carbohydrates. They are to the plant world what a barrel of refined oil is to the hydrocarbon world. Indeed, aside from hydrocarbons they are the most concentrated form of true wealth—sun energy—to be found on the planet.1

The advent of intensive maize (corn) agriculture among indigenous American societies during late prehistory not only had profound effects on the pre-Columbian landscape as a whole but also on the freshwater mussels, in particular the “river mussel.” According to evidence from shell middens, the relative abundance of these mussels has declined steadily during the last five thousand years, a decline that could be interpreted as the result of either an increase in direct human impacts on streams or of long-term, non-anthropogenic changes in climate. Nevertheless, decline of these mussels increased significantly in the southeastern United States about one thousand years before the present—a decline attributable to the advent of large-scale, intensive maize agriculture. The data suggest that such land use by early indigenous Americans wrought changes in communities of freshwater mussels that were portents of the deleterious environmental effects intensive agriculture is causing today.2 And what, you might ask, are some of the problems?

Today’s large acreages of intensively farmed crops in the United States, which are addicted to toxic pesticides, host fewer species of birds than do smaller, organic farms. In addition to insecticides, the loss of habitat or its declining quality (or both) through fragmentation can also have strong, negative impacts on indigenous populations of insects, which in turn affect insect-eating birds and bats. For example, when prairie remnants in Nebraska are converted to agriculture, there is an overflow of generalist predatory insects, such as the ladybird beetles, that begin to consume the herbivorous insects indigenous to the prairie ecosystem. In other words, populations of native insects decline when confronted with an increasing loss of habitat to agriculture, and there is then a corresponding upsurge in populations of predatory species having a generalist proclivity.

As with everything else, agricultural intensification has consequences. But people keep trying to push Nature into ever-higher production. Corn, it turns out, is one of the most energy-intensive crops when it comes to the amount of fertilizer it requires, and farmers are applying seven times the amount of synthetic nitrogen as they did in the late 1960s. Although the production of grain has doubled since then, largely because of the widespread use of synthetic fertilizers, pesticides, and intensive irrigation, the current rate of increased agricultural output is unsustainable, as evidenced since the late 1980s by diminishing returns in crop yields, despite the increased application of fertilizers.3

The environmental consequence of a farmer’s and the soil’s addiction to synthetic chemicals is compromising bacterial nitrogen fixation, thereby increasing dependence on synthetic nitrogenous fertilizer, while simultaneously reducing soil fertility and increasing the long-term non-sustainability of crop yields and increasing the demand for fossil fuels.4

Beyond the application of synthetic fertilizers, the natural gas used in their production accounts for 90% of the cost of the ammonia, which is the basis for the nitrogen fertilizer applied to corn. The pesticides and herbicides required to produce these vast monocultures are also gas-based petrochemicals—and thus increases the amount of anthropogenically produced carbon dioxide emitted annually into the atmosphere. And then there is the substantial amount of diesel fuel needed to operate the farm machinery. And this says nothing of the enormous quantity of water this exceedingly thirsty crop requires—1,700 gallons of water for each gallon of ethanol produced.5

In the Great Plains, where new ethanol plantations are being established, an unexpected environmental cost is exacted because groundwater is the only source for irrigation. As water soaks through the soil, it collects carbon dioxide from decomposing organic matter in the soil through which it percolates. According to Gwen L. Macpherson, a hydrogeologist at the University of Kansas in Lawrence, groundwater holds, on average, from 10 to one 100 times as much carbon dioxide as water in lakes and rivers.6

Thus, when groundwater is pumped to the surface, the carbon dioxide escapes into the air, where it adds to the growing supply of greenhouse gases. Nonetheless, people have been pumping about 178 cubic miles of water from below ground annually and thereby have been releasing approximately 331 million tons of carbon dioxide into the atmosphere every year. Although the volume of carbon dioxide released from the groundwater is a small percentage of that produced from the combustion of fossil fuels, it is about three times the amount spewed from the throats of volcanoes, which are a natural source of the greenhouse gas.7

CARBON DIOXIDE AND OCEAN ACIDIFICATION

In addition to problems with the use of inorganic fertilizers is the fact that manufacturing these fertilizers concomitantly produces carbon dioxide from the burning of fossil fuels. In turn, the world’s oceans absorb carbon dioxide from the atmosphere in a direct air-to-ocean exchange, which theoretically and ideally reaches a sort of equilibrium.

The global oceans are the largest, natural reservoir of carbon dioxide. They absorb about one-third of the carbon dioxide we humans spew into the atmosphere every year. Although this process is extremely slow, taking hundreds to thousands of years, once dissolved, a carbon atom can remain in the water for decades or centuries depending on the depth in the ocean in which it is located. However, anthropogenic carbon dioxide now penetrates the whole water column of the North Atlantic Ocean.8

Moreover, there’s a strong possibility that dissolved carbon dioxide in the ocean’s surface waters will double over its pre-industrial levels by mid-21st century and will be accompanied by even greater acidity as well as by a decrease in the carbonate ion. When carbon dioxide reacts with seawater, it produces carbonic acid, which can be thought of as the soda-water effect. This change in seawater chemistry is having profoundly negative effects on the calcium-secreting organisms in the world’s oceans because they depend on calcium carbonate for the production of their shells (mollusks, including planktonic mollusks, and marine algae) and skeletons (corals).

In fact, these species already have a reduced ability to produce their protective shells (oysters, snails, and others) and supportive skeletons (coral). In addition, the increase in carbonic acid is even now beginning to dissolve the shells and skeletons once they are produced, which is making them increasingly susceptible to wear and erosion. In other words, shells are dissolving with living animals still inside. Decreased calcification will no doubt compromise survival of these organisms and will shift marine flora and fauna toward non-calcifying species. For example, the common periwinkle (a small marine snail) normally grows extra-thick shells when living among crabs, but the snail’s ability to produce a thicker-than-normal protective shell is disrupted if the water is too acidic.9

As well, ocean acidification points to coming troubles for marine fish, such as Atlantic cod and a small, estuarine fish known as silversides. With respect to silversides, hatchling survival from currently-fertilized eggs fell steadily from about 50% at around 410 parts per million of carbon dioxide in the seawater, to about 10% at 1,000 parts per million—a concentration scientists predict may occur by the end of this century. Moreover, silverside eggs incubated in moderately acidified water (600 parts per million of carbon dioxide) were far less likely to survive than were eggs in water at current levels of acidity. According to Hannes Baumann from Stony Brook University in New York, carbon dioxide levels of around 600 parts per million could occur within 40 years. Further, the length of Hatchling also fell, and rates of severe body malformations rose in correspondence to the elevated levels of carbon dioxide in the water.

In Europe, Balitc cod grew faster, matured later, and died at progressively higher rates when exposed to elevated concentrations of carbon dioxide. In addition, they exhibited higher rates of severe damage, such as the death of tissue death and malformations, in a host of organs including the liver, pancreas, kidney, and gut.10

Other studies show that, if acidification continues unabated, the impairment of sensory ability of larval fish to find adult habitat (homing ability) will reduce the population sustainability of many marine species, with potentially profound consequences for marine diversity. As well as alter the potential of some species of fish to detect predators or move in habitual patterns.11

On a global scale, the alterations in surface-water chemistry from the anthropogenic deposition of nitrogen, sulfur, and dissolved inorganic carbon are relatively slight compared with the acidification caused by the oceanic uptake of anthropogenic carbon dioxide. If the anthropogenic emissions of carbon dioxide do not abate soon, the complex fabric of marine ecosystems will begin to fray—and eventually unravel completely. The impacts are more substantial in coastal waters, however, than in the deep ocean. In coastal areas, the ecosystem responses to acidification will have severe implications for people, especially those who rely on the seas of the world for food.

These changes are already sending ripples throughout the marine food web—from the microscopic plankton to the plankton-feeding whales and all life in between—and will only increase over time. As the ocean gets warmer and more acidic, the amount of dissolved oxygen will diminish accordingly, which will magnify the severity of the oceanic dead zones (oxygen-deprived areas), as well as the availability calcium carbonate required by coral and other calcium-secreting organisms.12

Coral reef ecosystems are among the most biologically diverse on Earth. In addition, they provided food, medicines, and other resources for over 500 million people worldwide. Despite their importance, they are declining at a rate of 1-2% annually as a result of local overfishing, declining water quality, global warming, and oceanic acidification. Although the exact response of coral reefs to the acidification of seawater is unknown, it’s highly likely that coral-dominated reef systems will be present in tropical oceans of the future at the current rate of their warming and acidification.13

One possible reason is that oceanic acidification undermines successful sexual reproduction, settlement of larvae, and post-settlement survival and growth. The cumulative impact of seawater acidification on fertilization and settlement is an estimated 52% and 73% reduction in the number of larval settlers on the reef under present levels carbon dioxide projected for the middle and the end of this century, respectively. Moreover, high levels of carbon dioxide caused a 50% decline in post-settlement larvae compared to the current seawater levels. This study suggest that oceanic acidification has the potential to cause multiple, sequential changes in the early-life-history stages of corals, thereby severely compromising sexual recruitment and the ability of coral reefs to recover from disturbance.14

“You don’t have to believe in climate change to believe that this is happening,” says Joanie Kleypas, an oceanographer with the University Corporation for Atmospheric Research in Boulder, Colorado. “It’s pretty much simple thermodynamics.” According to Kleypas, “Acidification is more frightening than a lot of the climate change issues” because it’s much harder to turn around. “It’s a slow-moving ship, and we’re all trying to row with toothpicks.”15

Consider, for example, that the severity of human-induced climate change depends not only on the magnitude of the change but also on the potential for reversibility. Reversibility, in this sense, means the degree by which the production of anthropogenically produced carbon dioxide is reduced within this century. As far as Nature’s biophysical principles are concerned, however, nothing is ever reversible because the entire oceanic ecosystem will have changed—and will continue to do so indefinitely.

Data show that the effects of climate change taking place due to increases in the concentration of carbon dioxide will remain in affect of 1,000 years after emissions are halted. Following the cessation of emissions, the amount of heat trapped in Earth’s atmosphere will decline, but that decline will be offset by a slower loss of heat to the ocean, which means that atmospheric temperatures do not drop significantly for at least 1,000 years.

What, you might wonder, are some of the physical impacts of a warmer climate over the next 1,000 years or so. Should concentrations of atmospheric carbon dioxide increase from current levels near 385 parts per million by volume to a peak of 450–600 parts per million by volume over the coming century, dry-season rainfall would be reduced in several regions comparable to those of the “dust bowl” era. In addition, seawater expands as it warms, which increases sea level. When the volume of water from melting glaciers and ice sheets is added to the expanded seawater, the future rise in sea levels may well be several feet over the next millennium or longer.16 And, these are just two outcomes of global warming wherein the world’s oceans will play a part.


Oceans in Crisis:

• Meeting The Ocean

• Resource Overexploitation

• Overfishing

• Marine Protected Areas

• Chemical Pollution

• Human Garbage

• Noise

• Temperature

• Lessons We Need to Learn For the Sake of All Generations

Related Posts:

1. What Is A Commons?

4. The Ocean, Mother Of All Waters

• Principle 1: Everything is a relationship

• Principle 6: All relationships are self-reinforcing feedback loops

• Principle 6: All relationships are self-reinforcing feedback loops

• Principle 9: All relationships are irreversible

• Principle 11: All systems have cumulative effects, lag periods, and           thresholds


ENDNOTES

1. Richard Manning, “The Oil We Eat,” Harper’s, February 2004, 37–45.

2. Evan Peacock, Wendell R. Haag, and Melvin L. Warren Jr. Prehistoric Decline in Freshwater Mussels Coincident with the Advent of Maize Agriculture. Conservation Biology, 19 (2005):547–551.

3. Lester R. Brown. Can We Raise Grain Yields Fast Enough?” World•Watch, 10 (1997):8–17.

4. Jennifer E. Fox, Jay Gulledge, Erika Engelhaupt, and others. Pesticides Reduce Symbiotic Efficiency of Nitrogen-Fixing Rhizobia and Host Plants. Proceedings of the National Academy of Sciences, 104 (2007):10282–10287.

5. (1) Tad W. Patzek. Thermodynamics of the Corn-Ethanol Biofuel Cycle. Critical Reviews in Plant Science, 23 (2004):519–567; (2) David Pimentel and Tad W. Patzek. Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower. Natural Resources Research, 14 (2005):1, 65–76; (3) Jason Hill, Erik Nelson, David Tilman, and others. Environmental, Economic, and Energetic Costs and Benefits of Biodiesel and Ethanol Biofuels. Proceedings of the National Academy of Sciences, 103 (2006):11206–11210; (4) Manfred Kroger. Forum: Corn Is Food, Not Fuel. Pittsburgh Post-Gazette, April 8, 2007; (5) Alice Friedemann, Peak Soil: Why Cellulosic Ethanol, Biofuels Are Unsustainable and A Threat To America. http://culturechange.org/cms/index.php?option=com_content&task=view&id=107&Itemid=1; (6) Lian Pin Koh. Potential Habitat and Biodiversity Losses from Intensified Biodiesel Feedstock Production. Conservation Biology, 21 (2007):1373–1375; and (7) Sid Perkins. Groundwater Use Adds CO2 to the Air. Science News, 172 (2007):301.

6. Sid Perkins. Groundwater Use Adds CO2 to the Air. op. cit.

7. Sid Perkins. Groundwater Use Adds CO2 to the Air. Ibid.

8. (1) Rosane Gonçalves Ito, Bernd Schneider, and Helmuth Thomas. Distribution of Surface fCO2 and Air-Sea Fluxes in the Southwestern Subtropical Atlantic and Adjacent Continental Shelf. Journal of Marine Systems, 56 (2005):227–242 and (2) Helmuth Thomas and Venugopalan Ittekkot, “Determination of Anthropogenic CO2 in the North Atlantic Ocean Using Water Mass Ages and CO2 Equilibrium Chemistry. Journal of Marine Systems, 27 (2001):325–336.

9.The discussion of ocean acidification is based on: (1) Jonathan Shaw. The Great Global Experiment: As Climate Change Accelerates, How Will We Adapt to a Changed Earth? Harvard Magazine, 105 (2002):34–43, 87–90; (2) Kathy Tedesco, Richard A. Feely, Christopher L. Sabine, and Cathrine E. Cosca. Impacts of Anthropogenic C02 on Ocean Chemistry and Biology. NOAA Archive of Spotlight Feature Articles, 2005, http://www.oar.noaa.gov/spotlite/spot_gcc.html; (3) Lisa Stiffler. Research in Pacific Shows Ocean Trouble. Seattle Post Intelligencer, March 31,2006; (4) Ruth Bibby, Polly Cleall-Harding, Simon Rundle, and others. Ocean Acidification Disrupts Induced Defenses in the Intertidal Gastropod Littorina littorea. Biology Letters, 3 (2007):699–701; (5) Scott C. Doney, Natalie Mahowald, Ivan Lima, and others. Impact of Anthropogenic Atmospheric Nitrogen and Sulfur Deposition on Ocean Acidification and the Inorganic Carbon System. Proceedings of the National Academy of Sciences, 104 (2007):14580–14585; (6) J. C. Blackford and F. J. Gilbert. pH Variability and CO2 Induced Acidification in the North Sea. Journal of Marine Systems, 64 (2007):229–241; (7) Igor P. Semiletov, Irina I. Pipko, Irina Repina, and Natalia E. Shakhova. Carbonate Chemistry Dynamics and Carbon Dioxide Fluxes across the Atmosphere-Ice-Water Interfaces in the Arctic Ocean: Pacific Sector of the Arctic. Journal of Marine Systems, 66 (2007):204–226; and (8) O. Hoegh-Guldberg, P. J. Mumby, A. J. Hooten, and others. Coral Reefs under Rapid Climate Change and Ocean Acidification. Science, 318 (2007):1737–1742.

10. The preceding two paragraphs are based on: Janet Raloff. Acid Test Points To Coming Fish Troubles. Science News, http://www.sciencenews.org/view/generic/id/336901/title/Acid_test_points
_to_coming_fish_troubles

11. (1) Philip L. Munday, Danielle L. Dixson, Jennifer M. Donelson, and others. Ocean Acidification Impairs Olfactory Discrimination And Homing Ability Of A Marine Fish. Proceedings of the National Academy of Sciences, 106 (2009):1848–1852 and (2) Janet Raloff. Acidification Alters Fish Behavior. Science News, 181(2012, number 4):14.

12. (1) Kathy Tedesco, Richard A. Feely, Christopher L. Sabine, and Cathrine E. Cosca. Impacts of Anthropogenic C02 on Ocean Chemistry and Biology. NOAA Archive of Spotlight Feature Articles, 2005, http://www.oar.noaa.gov/spotlite/spot_gcc.html and (2) Janet Raloff. Carbon Dioxide Erodes Marine Ecosystems. Science News, 181 (2012, number 5):10.

13. (1) O. Hoegh-Guldberg, P. J. Mumby, A. J. Hooten, and others. Coral Reefs under Rapid Climate Change and Ocean Acidification. Science, 318 (2007):1737–1742 and (2) Ove Hoegh-Guldbereg. Regional Environmental Change, 11 (2011):S215-S227

14. Rebecca Albright, Benjamin Mason, Margaret Miller, and Chris Langdon. Ocean Acidification Compromises Recruitment Success Of The Threatened Caribbean Coral Acropora Palmata. Proceedings of the National Academy of Sciences, 107 (2010): 20400-20404.

15. Kathy Tedesco, Richard A. Feely, Christopher L. Sabine, and Cathrine E. Cosca. Impacts of Anthropogenic C02 on Ocean Chemistry and Biology. op.cit.

16. The preceding three paragraphs are based on: (1) Susan Solomon, Gian-Kasper Plattner, Reto Knutti, and Pierre Friedlingstein. Irreversible Climate Change Due To Carbon Dioxide Emissions. Proceedings of the National Academy of Sciences, 106 (2009):1704–1709 and (2) Radiative Forcing. http://web.mit.edu/newsoffice/2010/explained-radforce-0309.html


Text © by Chris Maser 2012. All rights reserved.

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If you want to contact me, you can visit my website. If you wish, you can also read an article about what is important to me and/or you can listen to me give a presentation.



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