Logo der Sektion Phykologie

Phycology Section

of the German Botanical Society (Deutsche Botanische Gesellschaft, DBG, e.V.)

Press Release

21st Jan 2009

Alga of the year 2009: Emiliania huxleyi – an algal dwarf which impacts on the global climate

Algal researchers of the German Botanical Society have chosen Emiliania huxleyi as alga of the year to highlight its importance as a global key organism.

‘Due to its global importance, Emiliania has been included in the sequencing programme of the Joint Genome Institute in California where its genetic composition will be analysed’, explains Professor Dr Peter Kroth, Chairperson of the Phycology Section of the German Botanical Society. An improved understanding of its genetic make-up will assist in researching the global carbon cycle.

Industry awaits genetic key

Unravelling the mechanism by which the algae can produce little calcified platelets or scales called ‘coccoliths’ (or ‘liths’) and attach these to their surfaces has also potential future applications. Further research in this field may result in new industrial uses in bio- and nanotechnology.

The translocation of lime has created chalk cliffs

Emiliania lives in the well-lit layers of all oceans. It is one of over 300 species of calcified microalgae called coccolithophores which are surrounded by small, distinct calcified platelets which give each species its unique look. Emiliania uses carbon to form these lime-based platelets; carbon is accumulated from the surrounding water in the form of bicarbonate and precipitated as calcite. The liths can only be seen using a scanning electron microscope – they appear as little dots under plain light microscopy. At the end of their lives, coccolithophores sink to the bottom of the oceans and the bound carbon is deposited at great depths forming sediments. In this way lime has been deposited for millions of years on the seafloor: the white cliffs of Dover in England and the chalk cliffs of the Island of Rügen ( Baltic Sea ) are evidence of such ancient sedimentation processes.

Emiliania dominates many algal blooms

Even though Emiliania is only a tiny microalga, it plays a significant role in the global carbon cycle. Its enormous contribution is due to its ability to multiply at an explosive rate: under certain environmental conditions Emiliania reproduces very fast, accumulates in large quantities and forms so-called algal blooms. These can extend over several hundred square kilometres and are even visible from space because they give the surface layers of the oceans a milky appearance. Algal blooms are often almost entirely made up by Emiliania cells which may contribute up to 80 or 90 per cent of the overall phytoplankton community.

Biological carbon pump

Emiliania is very important as it binds, during photosynthesis, a large quantity of the greenhouse gas carbon dioxide which, when the cells die, is transported into the deeper layers of the oceans. Scientists describe this process as the ‘biological pump’. Additionally Emiliania produces calcium carbonate which leads to an acidification of the seawater, which, in turn, results in the increased release of carbon dioxide (the so-called ‘carbonate pump’). Both processes have differential impacts on the oceans’ carbon-binding capacity.

Scientists are fascinated by Emiliania’s success

Anthropogenic increase in carbon dioxide leads to acidification of the oceans in the long-term. Scientists at the Alfred-Wegener-Institute in Bremerhaven currently investigate the ability of Emiliania to bind carbon and deposit this in the deep sea, and whether this will enhance or buffer climate change effects. ‘We try to answer such open questions by researching how Emiliania can cope with ocean acidification and what consequences this has for the wider marine ecosystem’ explains Dr Björn Rost, Leader of the ‘PhytoChange’ research group which focuses on consequences of climate change on marine phytoplankton. ‘Emiliania is particularly fascinating; we are constantly amazed and try to comprehend how this species can become so dominant in certain regions’.

Images

Mass reproduction of coccolithophores in the Barents Sea , caught by a NASA satellite. When the algae die, the calcified platelets are released into the water and scatter sunlight so that the water appears light blue. Platelets of intact algal cells do not scatter light. Therefore, whether coccolithophores dominate an algal bloom or not can only be seen from space once most individuals have already died and released their calcified platelets.
Photo: Jacques Descloitres, NASA/GSFC, MODIS Rapid Response
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Algal bloom off the coast of Iceland , documented by NASA. The turquoise traces in the water suggest that billions of Emiliania huxleyi are present in the phytoplankton.
Photo: NASA/GSFC, MODIS Rapid Response
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Calcified scales cover Emiliania huxleyi. The shape of the liths is characteristic of different species of coccolithophores but can only be distinguished under Scanning Electron Microscopy, as in this image.
Photo: Dr. Björn Rost, Alfred-Wegener-Institut für Polar- und Meeresforschung
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Image rights

Use of the image by Dr. Björn Rost is only permitted in connection with reporting on the topic ‘Alga of the Year 2009’ and only if the photographer is acknowledged in the format: first name, surname, institution. If you would like to use the images for any other purpose please contact Dr. Björn Rost (details above). Terms and conditions for use of NASA images are available at http://visibleearth.nasa.gov/useterms.php.

Note for publishers

In case of a publication please send a copy to Dr. Burkhard Becker, Botanisches Institut, Universität zu Köln, Gyrhostraße 15, 50931 Köln.
E-mail: medien@dbg-phykologie.de

Contacts for the media

Prof. Dr. Peter Kroth

Chairperson Phycology Section of the German Botanical Society

Universität Konstanz
Fachbereich Biologie

Tel. ++49 (0) 7531-884816

E-Mail: peter.kroth@uni-konstanz.de

Dr. Björn Rost

Leader of research group PhytoChange & expert on Emiliania

Alfred-Wegener-Institut
Bremerhaven

Tel.: ++49 (0) 471/4831-1809 (9-15 Uhr)

E-Mail: Bjoern.Rost@awi.de

Further information

Sektion Phykologie: www.dbg-phykologie.de
Members of the Phycology Section (Algology) conduct research on algae and investigate, amongst others, taxonomical, ecological, physiological and molecular topics on macro- and microalgae. The Section is one of five subject-specific Sections of the German Botanical Society (Deutsche Botanische Gesellschaft, DBG e.V.: www.deutsche-botanische-gesellschaft.de)

Text

by Dr. Esther Schwarz-Weig www.sci-stories.com, translated by Dr. Dagmar Stengel

Contents:

Images
Note for publishers
Contacts
Further information
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Click image for information