What IS Bioluminescence?

Cover of Woody Hastings' bookSimply put, bioluminescence is the ability of living organisms to generate light; it is biological light. It sounds bizarre, but in fact it is not that uncommon, especially in the deep oceans. It developed very early in evolution when all life was found in marine environments. It is estimated that bioluminescence has evolved independently at least 40 times over many different groups of organisms, including about half of all phyla and in 35% of all classes within those phyla. However, despite this wide distributuion the actual number of luminescent species is low.

Bioluminescence involves a chemical reaction (chemiluminescence) that releases light so efficiently that it produces hardly any heat. The phenomenon has fascinated humans since ancient times, and is being used today in many different contexts, from medicine to warfare to biotechnology.

Bioluminescence is a form of phosphorescence, which is defined by the Oxford English Dictionary (OED) as "emission of light without any perceptible heat; the light so emitted." Fluorescence is different: it is the "distinctive luminosity shown by some substances when illuminated with light, esp. ultraviolet light; the emission of light by a substance as it absorbs light or other electromagnetic radiation of a different (usually shorter) wavelength. Also: the property of a substance of possessing this property" (OED 2006). A fluorescent glow ceases when the illumination stops.

This Guide has been created in conjunction with a temporary exhibit (February-June 2013) about Bioluminescence in the Northwest Building lobby at Harvard University. It gives a brief overview of the subject, its mechanisms, functions and uses, and describes a few of the many organisms that luminescence in various ways and for various purposes.

The guide is dedicated to the memory of Woody Hastings.

Both the exhibit and this Guide would not have been possible without the assistance of many members of Harvard's faculty and staff. Thank you all!


The exhibit on Bioluminesence in the Northwest Building lobby at Harvard was funded by the Harvard Library Lab, established “in order to create better services for students and faculty and to join with others in fashioning the information society of the future.

By offering infrastructure and financial support for new enterprises, the Lab offers opportunities for individuals to innovate, cooperate across projects, and make original contributions to the way libraries work.” The website is http://osc.hul.harvard.edu/liblab.

Library Lab receives generous additional funding from the Arcadia Fund.

The Lab is under the auspices of the Office of Scholarly Communication (OSC), which “spearheads campus-wide initiatives to open, share, and preserve scholarship.”

Many Thanks ...

Acknowledgments: Many people have contributed to the exhibit and this accompanying webguide. In no particular order, thanks to Renate Hellmiss, MCB Graphics; Karsten Hartel, Chris Kenaley and Andrew Williston of the OEB Ichthyology Department; Jan Sacco and Tristan Rocher of HMNH Exhibits; Adam Baldinger and Murat Recevik of MCZ Invertebrates and Mollusks; Phil Perkins and Rachel Hawkins of Entomology; Gonzalo Giribet of Invertebrates; Victoria Wilke of MCZ; and of course Woody Hastings, who inspired the idea and whose new book launched the exhibit. But many more, too numerous to name, have given their support, knowledge and encouragement. Thank you all!