Single-Celled Creature Has Eye Made of Domesticated Microbes
By Ed Yong

Under the microscope, each warnowiid contains a conspicuous dark dot. This is the ocelloid. It consists of a clear sphere sitting in front of a dark red strip, and has components that resemble a lens, an iris, a cornea, and a retina.

Eyes are meant to be animal inventions. They’re supposed to comprise many cells. They are icons of biological complexity. And yet, here’s a non-animal that packs similar components into its single cell. Is the ocelloid actually an eye? Can it sense light? What does a warnowiid use it for? These questions are still mysteries, but in trying to answer them, Gregory Gavelis from the University of British Columbia has discovered something about the ocelloid that’s even weirder. At least two of its components—the “retina” and the “cornea”—seem to be made from domesticated bacteria.

Glowing Sky, Glowing Water

Over the last week, the island of Tasmania has seen its southern shores glowing. The lower blue glow is produced by dinoflagellates – a type of single-celled organism common throughout the ocean that gives off light through a chemical reaction. This species tends to light up when it is disturbed, whether by action of humans or simply by the waves. When they suddenly grow in an area in large amounts, they can be washed ashore, causing a glowing line along the bach.

There are many bioluminescent species in the ocean – deep in the ocean that can be the only source of light – and the exact color of light given off by each varies slightly depending on the exact chemistry used. Pale blue hues like these are particularly common as blue light travels farther than more reddish light through water.

This pale glow was captured beneath the glow of another light – the Milky Way galaxy – by James Garlick – and shared on our wall with permission. Thanks!


Image credit: http://on.fb.me/1Pxiqo4
The Photographer’s page (prints available if you contact through there):

Read more: http://bit.ly/1KkkX1b

The Gippsland Lakes in Australia is a beautiful example of bioluminescence.   Noctiluca scintillans, commonly known as Sea Sparkle, is the non-parasitic, marine-dwelling dinoflagellate that exhibits the bioluminescence throughout its cytoplasm when disturbed.


Sea Sparkle (Noctiluca scintillans)

Also known as the sea ghost or fire of the sea, the sea sparkle is a species of free-living marine dinoflagellate that is widely distributed throughout the world. Sea sparkles are often found along coasts, estuary and shallow areas of continental shelves. N.scintillans is a heterotroph (meaning it gets its own food)  and will feed on other plankton like diatoms, fish eggs, bacteria and even other dinoflagellates via phagocytosis. Unlike other dinoflagellates N.scintillans goes through a life cycle that has a diploid and a haploid phase. True to their name sea sparkles are capable of bioluminescene and when they congregate in high concentrations (usually from environmental conditions) they are known as red tides. Although they are known as ‘red tides’ not all sea sparkle blooms are red, and color is derived from the pigments of organism inside the vacuoles of the sea sparkles. When disturbed N.scintillans will bioluminesce and produce a blue light earning them the ominous names of sea ghost and fire of the sea.


Chromalveolata-Dinoflagellata-Noctiluciphyceae-Noctilucales-Noctilucaceae-Noctiluca-N. scintillans

Images: Maria Antonia Sampayo and Hans Hillewaert


Multicellularity is often considered a prerequisite for morphological complexity, as seen in the camera-type eyes found in several groups of animals. A notable exception exists in single-celled eukaryotes called dinoflagellates, some of which have an eye-like ‘ocelloid’ consisting of subcellular analogues to a cornea, lens, iris, and retina

According to a canadian research team at the University of British Columbia, the single celled organism called  warnowiid dinoflagellate evolved a tiny version of a multi-cellular eye. In fact, contains a collection of sub-cellular organelles that look very much like the lens, cornea, iris and retina of multicellular eyes found in large animals.  The ocelloid, who is named the structure, could be used to detect shifts in light as it passed through their transparent prey

This process is known as convergent evolution, when different animals can evolve similar traits in response to their environments.

Warnowiids are found in marine plankton, little is known about their life histories, because they cannot be cultured in the laboratory, and samples obtained from the natural environment do not survive well under laboratory conditions

Light micrograph of a single Warnowia isolate. Scale bar = 10 microns, from Hoppenrath et al. 2009. 

The Bay of Fire

Imagine entering a quiet tropical bay at night. There are no lights on shore, and on a moonless night the spectacle is unforgettable. As the propeller of your boat churns the black water, an intense blue-green light is left behind, like an eerie trail of cool fire. Outside the bay you see a few sparks of light as you approach, but inside the bay things are very different. Long streaks of light shoot like fireworks beneath the boat. They are created by fleeing fish. A swim in the bay is even more spectacular. Your dive into the water is accompanied by a blinding flood of light, and sparks scatter out as you wave your arms.

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Also known as sea sparkle, Noctiluca scintillans is a large dinoflagellate that lives near the surface of the ocean, where it feeds on other planktonic organisms. It has a flattened spherical body but no protective test. It is colorless, although the presence of photosynthetic organisms within the cell may give it a pink or greenish tinge. This species, which is bioluminescent in some areas (noctiluca means “shining lantern”), may also form red tides and has been linked to fish and invertebrate deaths.

This is not a Photoshop or LED trick! 

This is Vaadhoo Island in Maldives; welcome to the world of Bioluminescence!

The biologically illuminated waves are due to the presence of light emitting phytoplankton. Bioluminescence results from energy released during chemical reactions occurring inside the organism. A very small fraction of the released energy is heat.

Most of the Pelagic Organisms (living in Open Ocean) exhibit this phenomenon. Since the Sun’s rays are not able to penetrate deep enough in sea water, sea creatures living in the realm of darkness (beyond 300m) have evolved to produce their own light.

Most of these organisms emit blue light. This is because it has a shorter wavelength, and thus has higher energy to travel farther through the sea water. An exception to this is Loosejaw which emits red light. Red light, having a longer wavelength, cannot travel long enough so this helps Loosejaws to remain invisible for the predators.

Bioluminescence serves different purposes for different organisms. It can be:
• To communicate
• To illuminate prey
• To attract mates
• Camouflage


(Photo Source: Doug Perrine, Alamy

Article References: 
1. National Geographic - http://news.nationalgeographic.com/news/2012/03/pictures/120319-glowing-waves-ocean-blue-bioluminescent-plankton-science

2. http://www.lifesci.ucsb.edu/~biolum/

3. http://www.waltonoutdoors.com/bioluminescent-waves-light-up-the-shoreline-at-grayton-beach/

For further study: 
1. NOAA - http://oceanservice.noaa.gov/facts/biolum.html

2. How Stuffs Work - http://science.howstuffworks.com/environmental/life/zoology/all-about-animals/bioluminescence1.htm)

though beautiful, these fluorescent blue patches of water are an indicator of a harmful algal bloom created by noctiluca scintillans, single celled organisms which become abundant when levels nitrogen and phosphorous from farm run off increase, and which proves toxic to the marine life that consumes it. the noctiluca also serve to deprive the water of oxygen, creating dead zones that are difficult for oceans to recover from.

while the evolutionary reason for their bioluminescence is still debated, varying from defensive purposes to communication to predatory strategy, the cause of this so called sea sparkle is better known; as the noctiluca float, movement in the water sends electrical impulses around a proton filled compartment inside the microorganisms, triggering a series of chemical reactions which ultimately activates luciferase, a protein that produces the neon blue light.

most marine bioluminescence is in the blue and green light spectrum, as these wavelengths pass furthest through seawater. interestingly, no known fresh water dinoflagellates have ever evolved bioluminescent abilities.

(click pic or link for credit and location xxxxxxxx, xxx)

Over the last week in Tasmania a dinoflagellate bloom by Noctiluca scintillans (also known as sea sparkle) has made for some amazing pictures.

Also known as a red tide during daylight, the bioluminescent algae glows a stunning blue if disturbed at night.


Image-Leena Wisby