Thursday, May 7, 2015

The Chemistry of Ancient Rome


Fig.1. Aqueduct of Segovia, a Roman aqueduct in modern-day Spain (Credit: Arian Zwegers, 2013, via Flickr).

At the height of the Roman Empire, aqueducts stretched across Europe and helped sustain a population of one million people in Rome alone. As water rushed through these engineering marvels, it often left behind layers of sediment along the walls, which built up for hundreds of years. A recent study has found that the sediment, often deposits of calcium carbonate, may provide a highly nuanced and localized picture of the climate during ancient times. Such a specific record of temperatures or precipitation, along with historical and cultural accounts, would shed light on how human societies adapt to climate change.

Analyzing isotopes


Many reliable Roman aqueduct sources were limestone cave springs, which are rich with dissolved calcium carbonate. When the water is exposed to air, this compound starts to fall out of the water and lines aqueduct walls in layers of deposit called calcareous sinter. The sinter was the object of interest for Gül Sürmelihindi and Cees Passchier, of the Johannes Gütenberg University of Mainz, who took samples from aqueducts in southern Europe and Turkey. They found that sinter built up in dark and light stripes with specific chemical compositions.

Sürmelihindi and Passchier tested each layer for the abundance of oxygen-18 (18O), a chemical isotope that contains more neutrons than the more common form of oxygen. In the darker stripes, they found a higher ratio of the heavier 18O, whereas the lighter stripes contained less of this heavy oxygen isotope. The difference could reflect changes in temperature. Calcium carbonate more readily stays dissolved in colder water, so any sinter accumulating during winter is more likely to contain 18O, which precipitates out of water faster than the less heavy and more common oxygen form. Sürmelihindi and Passchier believe that the darker layers of deposit correspond to a cooler environment, and the lighter layers show warmer temperatures.

Even though the isotope analysis supports the color gradation, the researchers acknowledged that other causes could underlie the layers’ chemical composition. Varied precipitation, the presence of biological material, or even human activity might affect isotopic ratios. Sürmelihindi and Passchier need to accurately date each layer, but such depositions could represent hundreds of years of local climate change and therefore a valuable resource.


Fig.2. Calcified remains of Eifel aqueduct near Euskirchen-Kreuzweingarten, Germany. The calcareous sinter has built up significantly along the inside walls of the aqueduct (Credit: Putput, 2006)


Recording the climate’s history


This study is not the first to examine the effect of climate change on ancient societies. Researchers have used ancient Roman trade routes to model how temperature affects human populations, whereas other projects linked the fall of the Mayan empire to drought after analyzing cave deposits. In order to study ancient climate, paleoclimatologists normally examine polar ice cores, deep ocean sediments, tree rings, or even pollen records. The advent of certain chemical techniques, however, opened the field to the study of stalactites and stalagmites, which can date as far back as 500,000 years.

Although Sürmelihindi and Passchier are still researching sinter, this new record of ancient climate variation offers an important addition to stalactite and stalagmite records. Such deposit records offer a much more localized view of ancient climate change and show nuances that ice or sediment cores are unable to capture. Furthermore, chemical changes in sinter can be compared to historical records of Roman culture, creating a picture of how they adapted to regional changes in the environment. These records are vital not only to track the rise and fall of ancient civilizations, but also to predict how modern day society might adjust to climate change.



References:

McDonnell, T. (2013, June 6), Slicing Open Stalagmites to Reveal Climate Secrets. Climate Desk. Retrieved from http://climatedesk.org/2013/06/slicing-open-stalagmites-to-reveal-climate-secrets/.

NOVA (2000, February 22), Watering Ancient Rome. Retrieved from http://www.pbs.org/wgbh/nova/ancient/roman-aqueducts.html.

Wendel, J. (2015, March 19), Ancient Roman aqueducts could spill climate secrets. Eos, 96, doi:10.1029/2015EO026629.





Glossary

calcareous sinter
Deposit of calcium carbonate that accumulates on objects exposed to the dissolved compound.
isotope
A type of atom that is still the same atom but varies in the number of neutrons.
neutron
A subatomic particle with no net electric charge that, along with protons, makes up the nucleus of an atom.
paleoclimatology
The study of climate change over all of Earth’s history. Such data is obtained from ice cores, ocean sediments, rocks, tree rings, micro-fossils, and more.

17 comments :

  1. Helpful article! Which you have given such good and informative knowledge on Ancient Rome. It's useful for me but also good for others who are searching for this information. Thanks for giving me information like this. Ancient Rome tour for kids

    ReplyDelete
  2. I am really appreciating your ideas regarding to tour place. as we provide Annapurna Circuit trek at affordable prices. for more info visit our website.

    ReplyDelete
  3. Well you have shared here information about tour and travels. as we provide BVI Vacation Deals Online at affordable prices. for more info visit our website.

    ReplyDelete
  4. When we find issues related to this type of subject that's not easy to find but some people like you make it easy for us. Thanks for giving us precious time. holiday packages for egypt

    ReplyDelete
  5. The article you've shared here is fantastic because it provides some excellent information that will be incredibly beneficial to me what to do in denver. Thank you for sharing that. Keep up the good work.

    ReplyDelete
  6. You have done good work by publishing this article here. I found this article too much informative, and also it is beneficial to enhance our knowledge. Grateful to you for sharing an article like this. online business reputation management

    ReplyDelete
  7. You've provided quite good information here. This is fantastic since it expands our knowledge and is also beneficial to us. Thank you for sharing this piece of writing. Expedition Travellers Private Jet Tours to Brazil

    ReplyDelete
  8. A very delightful article that you have shared here.magical breaks Your blog is a valuable and engaging article for us, and also I will share it with my companions who need this info. Thankful to you for sharing an article like this.

    ReplyDelete
  9. Thanks for the blog loaded with so many information. I’ll be sure to bookmark it and, come back to read more of your useful info.
    for More Information Visit Here:- Roadrunner Email Login Issues

    ReplyDelete
  10. Thank you for giving such good and useful information to us.
    Mini Tractor Price

    ReplyDelete
  11. Great content, Thanks for sharing this one.
    new tractor

    ReplyDelete
  12. Factful knowledge it is, Thanks for sharing this.
    Tractor

    ReplyDelete
  13. Hey, your blog have a nice content about chemistry.
    John Deere tractor

    ReplyDelete
  14. I really liked visiting your web site and very good blog and information given to us, thank you
    Mercedes benz buses.

    ReplyDelete
  15. Thank you so much that you shared such good knowledge, and I liked your post very much.
    Tempo traveller 12 seater price

    ReplyDelete
  16. Your blog entries make it quite clear that you are an expert in matters involving reckless driving. Your blog is a priceless resource because of the way you explain complicated legal concepts and provide clear legal insights. I appreciate you sharing your expertise! Essex County reckless driving lawyer

    ReplyDelete