Algae wins the race on climate change

In a changing climate, one of the biggest obstacles organisms face is whether or not they can adapt fast enough to survive. Luckily for Emiliania Huxleyi, evolution is not a problem.

Three individual Emiliania Huxleyi Phytoplankton (Young 2004)

 Thanks to the fast evolution of this phytoplankton, scientists have been able to study the potential long term effects of climate change on this alga and its consequent affect on the carbon cycle.

Emiliania huxleyi also known as "Ehux" are microscopic algae known as coccolithophores characterized by their outer shell of calcium carbonate disks.

Emiliania Huxleyi showing detached calcium carbonate disks (Beaumont K 2007)

Ehux are a fairly new species having evolved less than 250 milion years ago and are now one of the most abundant phytoplankton on earth (Bown et al 2004 and Moore et al 2012).

Their global adaptability is caused by a pan genome which allows very high genetic variance between individuals (Read et al 2013). 

Some of the different variations of Emiliania Huxleyi (Read et al 2013)

 Their role in ecology

Some ecological contributions of E.huxleyi (Gorrick G 2001)

Emiliania Huxley are primary producers and provide the baseline food source for most marine life. They also play an important role in the carbon cycle and can account for up to 20% of carbon cycling (Poulton et al 2007).  Under the right conditions algal blooms can be so large they can be seen from space (Moore et al 2012).  

Satelite picture of a coccolithophore bloom (NOC 2015)

Ocean Acidification

There has been major concern that ocean acidification will reduce the amount of carbonate available for E. Huxleyi to produce their shells. As a result, their shells could become lighter hence they would not sink to the ocean floor and the carbon in the CaCO3 shells would not sequester at the bottom of the ocean (Riebesell et al 2000).

The role of coccolithophores in the carbon cycle, “F” refers to CaCO3 disks sinking to the ocean floor and sequestering carbon in sedimentation (Hutchins D  2011)

Thanks to ehux’s fast evolution scientists have found that populations can change within 500 generations in one year through adaptive evolution (Lohbeck et al 2014). Furthermore, pre-adapted populations can perform 55% better in future climate change scenarios than current e-hux populations (Schluter et al 2014). This is good news for emiliania huxleyi and their potential affects on the carbon cycle.

Having said this, the high variation of results in past experiments on CaCO3 production in Emiliania Huxleyi shows that there is still much to learn about this species (Beaufort 2011).  

 Thank-you for reading : ) check back next week for more information on how climate is affecting marine evolution.

References

Bown P R, Lees J A, Young J R 2004, “Calcareous nannoplankton evolution and diversity through time”, Coccolithophores, pp. 481-508, doi: 10.1007/978-3-662-06278-4_18

Lohbeck K T, Riebesell U, Reusch T B H 2014, “Gene expression changes in the coccolithophore Emiliania Huxleyi after 500 generations of selection to ocean acidification”, The Royal society: Biological sciences, vol.281, no. 1786, doi: 10.1098/rspb.2014.0003

Moore T S, Dowell M D, Franz B A 2011, “Detection of coccolithophore blooms in ocean color satellite imagery: A generalized approach for use with multiple sensors”,  Remote sensing of environment, vol. 117, pp. 249-263, doi:10.1016/j.rse.2011.10.001

Poulton A J, Adey T R, Balch W M, Holligan P M 2007, “relating coccolithophore calcification rates to phytoplankton community dynamics: Regional differences and implications for carbon export”, Deep sea research part II: Topical studies in Oceanography, vol.54, no. 5-7, pp. 538-537, doi: 10.1016/j.dsr2.2006.12.003

Read B Am Kegel J, Klute M J, Kuo A, Lefebvre C, Maumus F, Mayer C, Miller J, Moneir A, Salamov A, Young J, Aguilar M, Claverie J-M, Frickenhaus S, Gonzalez K, Herman E K, Lin Y-C, Napier J, Ogata H, Sarno A F, Shmutz J, Schroeder D, de Vargas C, Verret F, von Dassow P, Valentin K, Van de Peer Y, Wheeler G, Emiliania Huxleyi Annotation Consortium, Dacks J B, Delwiche C F, Dyhrman S T, Glockner G, John U, Richards T, Worden A Z, Zhang X, Grigoriev I V 2013, “Pan genome of the phytoplankton Emiliania underpins its global distribution”,  Nature, vol.499, pp.209-213, doi: 10.1038/nature12221

Riebesell U,Zondervan I, Rost B, Tortell P D, Zeebe R E, Morel F M M 2000, “Reduced calcification of marine plankton in response to increased atmospheric CO2”, Nature, vol.407,pp.364-367, doi: 10.1038/35030078

Schluter L, Lohbeck K T, Gutowska M A, Groger J P, Riebesell G U, Reusch T B H 2014, “Adaptation of a globally important coccolithophore to ocean warming and acidification”, Nature climate change, vol.4, pp.1024-1030, doi: 10.1038/nclimate2379

Images

• NOC 2015, “Eutrophication and health” viewed 15/4/15, http://www.seos-project.eu/modules/oceancolour/oceancolour-c03-p04.html

• Young 2004, “Emiliania Huxleyi”, viewed 15/4/15, http://www.nhm.ac.uk/nature-online/species-of-the-day/biodiversity/climate-change/emiliania-huxleyi/index.html

• Hutchins D 2011, “Coccolithophore carbon chemistry”, viewed 15/4/15, http://www.nature.com/nature/journal/v476/n7358/fig_tab/476041a_F1.html

• Gorrick G 2001,”E. Huxleyi importance, viewed 15/4/15 https://microbewiki.kenyon.edu/index.php/File:E._huxleyi_importance.jpg 

• Read et al 2013, “Pan genome of the phytoplankton Emiliania underpins its global distribution” viewed 15/4/15 http://www.nature.com/nature/journal/v499/n7457/full/nature12221.html

• Beaumont K 2007, “Acidification”, viewed 15/4/15, http://www.antarcticanimation.com/content/thesaurus/a/acidification01.php