Thursday, April 26, 2012

Bioluminescence in Bacteria

Luminescence in marine organisms is far more common than would be expected.  Since many of the organisms live in deep ocean areas they are not very well studied or known.  However, there are many things about bioluminescent bacteria that are fairly well known.
The most common reaction used in creating bioluminescence in bacteria is catalyzed by luciferase.  When the bacteria let oxygen into their light organs it allows the oxygen to react with Luciferin and, catalyzed by luciferase, the reaction occurs to produce light.
The luciferin-luciferase reaction.
This is useful to medium to deep sea organisms because it can let them produce red light to blend into the complete darkness, or blue light to match ambient light from above and avoid predation, or light that will allow them to pull in prey.  This is the most obvious in the deep sea anglerfish that has a light organ on its head to attract prey.  In this light organ are symbiotic bacteria that allow the glowing to occur, but there are also bacteria like this that are free living.
A type of these free living bacteria, photobacterium, use their ability to glow as an attractant, but not for prey.  It is thought by some Harvard researchers that they use their glowing as an attractant to bring more predators to them.  In an experiment using both glowing and non-glowing bacteria it was found that a significant number of zooplankton would be more attracted to the glowing bacteria.  One the zooplankton ate the bacteria it began to glow and this caused it to be more susceptible to being eaten by bigger organisms such as fish.
It is thought that this is because the predators give them nutrients from the stomach and intestines and that the bacteria actually benefit from being eaten.  They are not broken down in digestion as shown in the figure below depicting a zooplankton after it has eaten the bacteria.  They were also traced from the digestive tract to the fecal matter of these zooplankton and fish.
Fig. 2.
Since they are not broken down this means that they can be eaten multiple times in order to make use of necessary nutrients in their host organisms.  This is an interesting means of gaining nutrients that sets this bacteria apart.
Research article

Wednesday, April 25, 2012

Great White Whale

I know I am done with my posts but I thought this was interesting and thought I would share it with everyone!

Tuesday, April 24, 2012

Presentation on Vampire Squids

The vampire squid is an impressive animal of the deep sea. They have over enlarged eyes that are a result of the dark environment in which they live in. They are considered to be living fossils because they have been around for such a long time. The animal lives at around 300 meters deep. They are found in the tropical and temperate regions of the world’s oceans. They are not very large; they grow to around 13 cm long. They have 8 arms and a long curly strand that acts as a sensory filament. They are technically not squids. It is thought to be an ancestral line between squids and the octopi. They do not produce in nor do they have the ability to change their coloration in order to blend into their surroundings.
       They have a unique defense mechanism that makes them very interesting. They have the ability to turn themselves inside out. Their tentacles come up over their body, giving them their name the “Vampire squid.” The one characteristic that they are known for is their defense mechanism that is to turn themselves inside out. 
The study that I particularly looked at for my presentation was done at Monterey Bay, California. The study was done in order to observe the luminescent clouds. They looked at 57 individuals in situ and they looked at 18 individuals in the laboratory aquarium. The vampire squids that were in the aquarium were recorded in complete darkness and under red light by the use of low light video cameras.    
       In particular, the study looked at the arm tips of the squid. They are known to hold the particles that glow. Then when the arms are put over the head and the mantle of the squid the particles are released. This puts the squid into what is known as a luminous cloud. The squid releases a few hundred to several thousand particles each time it makes the luminous clouds.  The glowing particles last between 2-3 minutes. Some trials happened to last as long at 9 minutes. In this study there was no way to measure the intensity of the luminescence. They could only record the amount of time that the particles were luminescent.

       The  light has been found to be emitted from the 2 fin- based photophores. The photophores are a light emitting organ that are found on deep water organisms. It is hypothesized that they use light to get away from predators. The light is thought to distract the predator long enough for the vampire squid to get away.
       Later on in the study they found that the luminous fluid was sticky, therefore when the squid released it into the surrounding water some of it stuck to the predator. This is interesting fact, because it leaves the predator glowing and it is more vulnerable to secondary predators.

The bright blue lights usually appeared as a tight chain of 4 to 6 small discs, tapering in size distally along the oral surface of each arm tip. Occasionally there were different patterns, in which the light appeared as two parallel lines separated by a dark gap. The green areas next to the arrows are where the particles are ejected from. They are less than 1mm wide.
To test for the presence of coelenterazine, they homogenized individual arm tips in 500 μl of methanol. The graph A above shows the light produced by methanolic extracts upon addition of Oplophorus luciferase, this indicated the presence of the luciferin coelenterazine. The graph B above shows the addition of coelenterazine to aqueous  extracts, it shows high luciferase activity. As the two graphs show the amount of light over a given period of time, graph B showed that the coelenterazine resulted in a more solid glow in comparison to sample A. This is represented by the linear line on the graph. It was also concluded that the Calcium chloride did not emit light, indicating that the calcium-activated photoprotein was not involved in making the particles glow.
It was concluded that the lights are used for intraspecific communication, attracting prey, and also to get away from predators. The arm tips glowed every time after the animal was handled. The luminous ejecta was never observed without the tip lights glowing as well. The light that was produced by the methanolic extracts upon the addition of Oplophorus luciferase indicates the presence of the luciferin coelenterazine.

Ocean Acidification

Ocean acidification has not yet been a major contributor to ocean problems but more and more studies have been focusing on this.  According to NOAA the ocean absorbs approximately a quarter of the Carbon Dioxide we release into the air every year.  As we discussed in class acidification of waters can happen through the reaction shown below and has the potential to hurt many habitats.  
Ocean Acidification Illustration
Since this is just recently becoming noticeable in the oceans first signs of effects on the wildlife are beginning to appear.  The most noticed problem is inability to form calcium carbonate structures, which has been effecting mostly corals and animal that secrete shells.  
In one study done at Oregon State University there was signs that acid environment during larval development of oysters lead to an inability to grow correctly and to low recruitment levels   This immediately has an affect on businesses using oysters and other shelled animals to make a profit, but will soon be noticeable in the environment.  The reduction of these animals may be an indication of future problems to come and act as a sort of "canary in the coal mine" for the ocean.   
Although the results of this ocean acidification have not been immediately evident there are beginning to be signs that it is affecting the wildlife.  Since there are calcium carbonate animals such as corals that are already being greatly reduced in numbers it is important the situation becomes controlled as soon as possible.  Also, since areas of upwelling will soon be bringing waters that were previously acidified the situation will not just get better on its own.  


Tuesday, April 17, 2012

Cool Coral Communities

Corals are animals in the Phylum Cnidaria, a coral polyp the main organism in the reef is made up of  a skeleton of CaCO3. The coral polyps are not the only ecosystem engineers of this community; sponges, bryozoans, sea anemones, fish, crabs, worms, and many other animals all call the Great Barrier Reef home. Being the world's richest area of diversity the animals all work together to survive in such a complex ecosystem. There are fish, Parrotfish, that play a major role in the life of coral reefs because the fish eat the seaweeds that over grow the coral. Even though this is a benefit to coral, Parrotfish also eat coral adding to the complex ecosystem found within coral reefs. Coral reefs provide not only food but protection for many animals. Because corals are so fascinating and unique many people desire to visit them. Tourism in the Great Barrier Reef is a huge economic advantage as well as a potential danger to the corals themselves. Runoff into the reef can pollute the ecosystem causing the corals to die off. The pollutants can cause disease and death with in the corals. This destroys one of the most beautiful places on earth.

 Tourists can break coral off while scuba diving or snorkeling slowly diminishing the reef little by little. Since the tourism of the reef is such a huge economic advantage for Australia, receiving two million visits a year, researchers have been discovering ways to protect the reef. NOAA's Coral Reef Conservation Program has been working on methods to preserve the reefs around the world. There is ongoing research around the world, the University of Miami in Florida is researching how to protect the reefs off the coast. While the University of Sydney is also doing research on understanding the coral communities. Much of the protection is regulating the tourists and the public to specific activities at certain times. Monitoring the fishing and the amount of water entering the reef are both ways the universities are helping to maintain their corals. The research on coral reproduction helps to place time frames for some restricted activities. Researchers are working on understanding the coral lifestyle to better protect the areas. Finding the presence of benthic organisms helps to define the habitat. On some reefs the benthic organisms are the problem, and others it is the fish. Depending on the characteristic of the reef, only specific organisms need protected to maintain the reef population. As more and more information is discovered about the fish and other creatures within this habitat better protection can be made.