Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Discover First Vertebrate with Eyes that Use Mirrors Rather than Lenses

28.01.2009
An international research team has discovered the first vertebrate with eyes that use mirrors rather than lenses to focus light. The spookfish, Dolichopteryx longipes, manages to focus light in the lower eye without using a lens. Light enters the lower portion of the eye and hits a mirror composed of stacks of crystals. This is the first time that this type of focusing mechanism has ever been found in a vertebrate.

Florida Atlantic University researcher and member of the Center for Ocean Exploration and Deep-Sea Research at Harbor Branch Oceanographic Institute, Dr. Tamara Frank, was part of an international research team that discovered the first vertebrate with eyes that use mirrors rather than lenses to focus light.

Results from this research have been published in the January issue of Current Biology. The article, titled “A Novel Vertebrate Eye Using Both Refractive and Reflective Optics,” describes the unusual eyes of the spookfish, Dolichopteryx longipes. These eyes are tubular, which are similar in structure to the eyes of many other fish that swim in the ocean’s twilight zone where the background light field is very dim.

“What makes this animal so unusual is that each eye is divided into two parts, one pointing upwards and one pointing downwards, making it look like it has four eyes, and four-eyed fish don’t exist,” said Frank.

In the few other species of deep-sea fish that possess split eyes, the upper eye has a lens, like in the spookfish, for focusing light. However, at these depths, there is so little upwelling light that a lens would attenuate light too much in its efforts to focus the light for the lower eye. Therefore, in other fish, the lower eye doesn’t have a lens, resulting in a blurred image. The spookfish however, manages to focus light in the lower eye without using a lens. Light enters the lower portion of the eye and hits a mirror composed of stacks of crystals. The stacks sit roughly parallel to one another, but their angle changes over the surface of the mirror, giving it an overall concave shape. A computer simulation by research team member Dr. Julian Partridge, Bristol University, United Kingdom, showed that orientation of the plates within the mirror's curved surface is perfect for focusing reflected light onto the fish's retina. This is the first time that this type of focusing mechanism has ever been found in a vertebrate.

Many deep-sea or night active animals (including dogs and cats) use mirrors behind the retina to make their eyes more sensitive to light, hence why their eyes seem to glow when a light shines on them. It has been estimated that this reflecting layer, the tapetum, doubles the sensitivity of the eyes that possess them. With these animals, the mirror sits behind the eye and cannot focus light. In the spookfish, the mirror sits in front of the retina and serves to focus light, providing an image that’s much brighter than a lens could produce.

“While this species was first described 120 years ago, the few specimens that have been collected in the past were dead and quite mangled, so very little could be discerned about their visual systems,” said Frank.

The expedition, led by Dr. Hans-Joachim Wagner from Tübingen University in Germany on the German research vessel Sonne, utilized Frank’s “Tucker Trawl,” built by Harbor Branch’s engineering division. The opening/closing net has a special temperature-insulated collecting vessel at the end that can be closed at depth. This feature enabled the scientists to secure the first-ever living specimen of this very rare fish from a depth of 700 meters over the Tonga Trench off Samoa. Pictures of the live animal immediately revealed that there was something unusual about the eye. Once back on land, the scientists examined the structure of the eye and discovered its unique properties.

About Harbor Branch:
Harbor Branch Oceanographic Institute at Florida Atlantic University is a research institute dedicated to exploration, innovation, conservation and education related to the oceans. Harbor Branch was founded in 1971 as a private non-profit organization, http://www.hboi.edu. In December 2007, Harbor Branch joined Florida Atlantic University.
About FAU:
Florida Atlantic University opened its doors in 1964 as the fifth public university in Florida. Today, the University serves more than 26,000 undergraduate and graduate students on seven campuses strategically located along 150 miles of Florida's southeastern coastline. Building on its rich tradition as a teaching university, with a world-class faculty, FAU hosts ten colleges: College of Architecture, Urban & Public Affairs, Dorothy F. Schmidt College of Arts & Letters, the Charles E. Schmidt College of Biomedical Science, the Barry Kaye College of Business, the College of Education, the College of Engineering & Computer Science, the Harriet L. Wilkes Honors College, the Graduate College, the Christine E. Lynn College of Nursing and the Charles E. Schmidt College of Science.

Gisele Galoustian | Newswise Science News
Further information:
http://www.fau.edu

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>