Foraminifera – tiny, single-celled marine life forms – build gorgeous houses that record how much ice there is on the planet.

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LEARN MORE

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To learn more about this topic, start your googling with these keywords:

• Foraminifera: a class of single-celled marine organisms – protists, not animals – that live either near the surface ("planktonic foraminifera") or on the seafloor ("benthic foraminifera"). Called forams for short.

• Climate proxy: something that tells us what the climate was like in the past, such as data from the thickness of tree rings, the composition of gases trapped in ancient ice, historical human records of annual bloom times (eg the long-recorded bloom dates of cherry trees in Kyoto, Japan), or the ratios of certain stable isotopes found in shells, corals, or other biogenic substances

• Oxygen-18: a stable isotope of oxygen that contains 8 protons and 10 neutrons, rather than the 8 protons and 8 neutrons of "regular" oxygen (oxygen-16). The ratio of oxygen-18 to oxygen-16 in seawater (and sea shells) can be used as a proxy for the global average temperature

• Ice sheet: a permanent layer of ice covering land, as found in polar regions (and as distinguished from sea ice, like the stuff that floats at the north pole in the Arctic ocean). Combined, the Greenland and Antarctic ice sheets contain more than 99% of the total freshwater ice on Earth.

FUN LINKS

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If you liked this week’s video, we think you might also like: The Tiniest Fossils by the AMNH - https://www.youtube.com/watch?v=JLSa8cGJixQ Orbulina feeding on Artemia - https://www.youtube.com/watch?v=BYQNt52tiVU Mysterious Web Masters - https://www.youtube.com/watch?v=q0WbN34Mh7k

CREDITS

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Script Writer: Emily Elert | Script Writer, Director & Narrator Kate Yoshida | Script Editor Ever Salazar | Illustration, Video Editing & Animation Nathaniel Schroeder | Music

Special thanks to Professor Lee Kump of Penn State University and Professor Howie Spero of UC-Davis for lending their advice, expertise, and patience to the making of this video!

This video was supported by the Heising-Simons Foundation. To learn more, visit https://www.heisingsimons.org/

MinuteEarth is produced by Neptune Studios LLC https://neptunestudios.info

OUR STAFF

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Emily Elert • David Goldenberg Henry Reich • Alex Reich • Peter Reich Ever Salazar • Kate Yoshida

IMAGE CREDITS

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Cribrohantkenina inflata - Paul Pearson https://museum.wales/articles/2007-08-03/Up-close-with-nature/

Elphidium macellum, Bulimina and Calcarina hispida by foraminifera.eu http://www.foraminifera.eu/

Globigerina - Hannes Grobe http://www.nhm.ac.uk/our-science/our-work/biodiversity/planktonic-forminera.html

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REFERENCES

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Hays, J. D., Imbrie, J., & Shackleton, N. J. (1976). Variations in the Earth's Orbit: Pacemaker of the Ice Ages. Science, 194(4270), 1121-1132. Abstract: http://science.sciencemag.org/content/194/4270/1121

Kendall, C., & McDonnell, J.J. (1998). Fundamentals of Isotope Geochemistry. In Isotope Tracers in Catchment Hydrology (pp. 51-86). Eds: Elsevier Science B.V., Amsterdam. Link: http://wwwrcamnl.wr.usgs.gov/isoig/isopubs/itchch2.html#2.3

Kucera, M. (2007). Planktonic Foraminifera as Tracers of Past Oceanic Environments. In Developments in Marine Geology, Volume 1, (pp. 213-262). Link: http://pmc.ucsc.edu/~apaytan/290A_Winter2014/pdfs/2007%20Proxies%20Chapter%20six.pdf

NOAA National Centers for Environmental Information, State of the Climate: Global Analysis for Annual 2015, published online January 2016, retrieved on November 28, 2016 from http://www.ncdc.noaa.gov/sotc/global/201513.

Sachs, J., & Steig, E. (2010) Lecture on Isotopes and Air Temperature. University of Washington, Seattle, Washington. Link: http://courses.washington.edu/proxies/AirTemperatureLecture2_2010.pdf

Shanahan, T. (2010). Lecture on Oxygen Isotopes. University of Texas, Austin, Texas. Link: http://www.geo.utexas.edu/courses/302c/L16-N.pdf