Glowing Mushrooms and Fireflies

I've been neglecting you dear Zoology blog. I am very sorry and I am going to try and post on here at least once a week to keep on top of my extra reading. This evening I would like to talk to you about a very interesting subject I had a lecture on this week, bioluminescence. Many of us will have seen examples of bioluminescence (without knowing the fancy word for it) in fireflies and some people may also have seen glow worms. The majority of bioluminescence however is found in the oceans.

animals.nationalgeographic.com

As you would expect, it is very hard to see when you live in a deep sea habitat. The photo above is a Anglerfish which lives in very deep regions of the ocean and looks very much like a scary alien from a sci-fi movie! As you can see, the Anglerfish has a lure which has a light on the end. If you have ever seen Finding Nemo you will know that it uses this lure to attract smaller fish for it to eat. Dragonfish have a similar lure which goes underneath them rather than over their mouth. Dragonfish also have a light next to their eye which is a wavelength that only they can see. This is a pretty nifty way of being able to see both predators and prey without them seeing you.

tech.ca.msn.com

Bioluminescence is also helpful for marine organisms avoiding predators. The Hawaiian Bobtail Squid uses a bacterium (Vibrio fischeri) to create light which it reflects from its body in the same direction as the moonlight and therefore obscures its silhouette in the water and makes it difficult for predators to see them. The image above is the deep sea octopus (Stauroteuthis syrtensis) which is one of the very few bioluminescent octopuses. Strangely, it is the suckers on this octopus which light up and the function of this is not yet known but could be to either attract prey or for communication. The bioluminescence shown in ocean species is generally either blue or green as these are the colours that travel the furthest. In terrestrial organisms the colours can vary greatly.

animals.nationalgeographic.com

As I mentioned earlier, fireflies are a well known example of bioluminescence and are one of the few terrestrial examples. Since fireflies are usually seen as little glowing dots I thought I would give you a close up picture of one. Different species of firefly use different colours of light depending on the time of day they use their light and the ability of that particular species to see different colours. Many species emit red light but we only see yellow or green light due to our eyes. These organisms use their light to attract mates so they can reproduce, which is very different from the marine organisms we have already talked about.

Wikipedia

Finally I would like to talk to you about bioluminescent mushrooms. That's right, glowing mushrooms. The picture above shows a tropical fungus which is often found on decaying matter such as wood or leaves. When conditions, such as temperature and water content of the soil are right, these fungi glow. At night insects are attracted to the fungi and carry away spores which are then dropped somewhere nearby. This allows maximum growth of the spores due to the good conditions.

Bioluminescence is a very interesting subject that is still being researched. It is unknown why many organisms spend so much energy on producing light and studies are currently going on to help us discover more about this fascinating subject. The animals I have mentioned about are only a few of the many examples of this phenomenon and many are still being discovered.

References:

•  Deheyn, D.D., Latz, M.I., 2007, Bioluminescence characteristics of a tropical terrestrial fungus (Basidiomycetes), Luminescence, Voll 22, pp 462-467
• Dehingia, N., Baruah, D., Siam, C., Gohain Barua, A., Baruah, G.D., 2010, Purkinje effect and bioluminescence of fireflies, Current Science, Vol 99 (10), pp 1425-1429
• Johnsen, S., Balser, E.J., Widder, E.A., 1998, Light emitting suckers in an octopus, Nature, Vol 398, p113
• Nyholm, S.V., McFall-Ngai, M.J., 2004, The winnowing: establishing the squid-vibrio symbosis, Nature, Vol 2, pp 632-643

A Decade Long Marine Census Comes To An End

Yeti Crab - Census of Marine Life

The Census of Marine Life which started in 2000 has finally been completed. It is estimated that during the census 20,000 new species have been discovered, bringing the number of known species to nearly 250,000. The decade long project cost £413m and aimed to find out what lived, lives and will live in the oceans. It involved more than 540 expeditions with over 2,700 researchers and used many new types of technology. Fish were tagged and seals were fitted with monitors to record when they dived. Acoustic systems were used to measure fish populations.

Dr Ian Poiner, the chairman of the project’s scientific steering committee, told the BBC “All surface life depends on life inside and beneath the oceans”. This is literally true because we know that life evolved from the oceans and the very first life forms were aquatic organisms. Back then the atmosphere did not have everything they needed to survive but the water did. It was a while before the air contained the nutrients that were needed but eventually life began to evolve on earth. It is thought that there could still be many undiscovered species in the oceans and there could be at least a million of them in total.

Many wonderful species have been discovered during this census, including a Jurassic Shrimp that has thought to have been extinct for at least 50 million years and a crab which has been named the Yeti Crab (see the picture at the top of this post). However, it wasn’t just large organisms that Dr Poiner’s project looked for. The census included trying to tell tiny microbes apart using genetic sequencing. If you thought that a million organisms was a lot then you will be surprised at how many different types of microbes are thought to be in the water – one billion. Hopefully the Census of Marine Life will serve as a base for us to build on to try and preserve marine life.

Source - MSN News