Dave Barlow © Cleveland Naturalists’ Field Club. 17th April 2015
Looking through the microscope for the first time I was fascinated but also very much aware that I didn't have clue what I was looking at! One of the things I really wanted to find was a Water Bear or Tardigrade which is Latin for slow walkers. This seems to be a creature that the general public has never heard about as well as many scientists and naturalists. I had read about them and was amazed at what these minute creatures were capable of. In some way their survival skills have taken them to a level that few if any creatures on the planet can emulate. They can be found all over the world from the tops of the Himalayas to the bottom of the deepest part of the ocean. More importantly you can find them in your back garden or anywhere outside. So just exactly where can you find these creatures? The best place to look is in a piece of moss that could dry out. As this is the key to their survival. They are able to withstand drying out completely.
These very small creatures are of special interest to scientists including NASA! Why you might ask would NASA be interested in a creature only 0.3 to 0.7 of a millimetre long. It is their ability to seemingly come back from the dead. When a piece of moss dries out the little Water Bears draw in their eight legs into their body and to all intents and purposes just die! They can lose more than 90% of their body water and simply go to a hibernation mode called a tun which is simply extraordinary. Scientists have experimented with these unfortunate little creatures and if they were higher order animal they might be accused of cruelty. I don't really know why the scientists pushed what these creatures can withstand but it is simply amazing and cannot be matched by any creature on earth.
Well what exactly can they endure?
They have been frozen to a degree above absolute zero and have been brought back to life. Not content with that test they then subjected them to a temperature of 151 °C which would kill even bacteria!
They have also subjected them to immense pressure which is something like 6 times the pressure that is at the bottom of the deepest part of the ocean. The scientists still trying kill these little bears then gave them a dose of radiation something like 1000 times more than would kill a human! Not content with this the ultimate challenge to these innocent bears was to take them into space. The problem for the tough little critters is that they put them on the outside of the spacecraft and left them there for 10 days to be bombarded with radiation 1000 times as much as on the surface of the earth. When they returned to earth and were rehydrated they woke up and actually laid eggs! The bears had passed all these tests and are the only creatures to survive being in outer space.
This is not all and is perhaps why NASA are interested in how they do it. A few years ago some scientists in Sweden were opening some dusty Victorian display cases that had some dried mosses in them. The scientists wet the mosses and to their astonishment the water bears that had been in the moss came back to life. The problem was that the moss had been in the case for 120 years!! This ability of the Water Bears ( which if you see them are actually cute) to withstand all this abuse has made some people question whether they actually came from outer space. The mechanism that they use to survive unharmed is totally amazing and the subject of continuing research. What is a fascinating thing to me is just how common these extraordinary creatures are and you will have them in your garden.
I have included some still images and video taken with a compact digital camera mounted on one of the two eyepieces on my microscope. The camera is mounted on a digiscoping clamp used really for a telescope although it works well on the microscope with a slight modification. Although Water Bears are fascinating creatures they are not the only interesting things in pond water or mosses. The other creatures which share some of the same abilities of the Water Bears is the Rotifers. They have the same ability to recover from drying out. This cryptobiosis is a process that only a few species have managed to achieve. The Rotifers are quite easy to identify as a group but trying to get to species level is much more of a challenge and currently beyond my skills. They all have minute cilia which they beat to draw in the microscopic soup of bacteria and other very small food items. They are basically filter feeders. The cilia look like rotating wheels as seen through the microscope hence their family name. There are of course lots of other inhabitants of this hidden world.
Of these an interesting one is the Vorticella this is a genus of protozoa, with over 16 known species. They are filter feeders that are attached to something on a long thread which is like a coiled spring. When they are touched by something they contract the spring back very quickly. The most common species is Vorticella campanula
As yet I have only just scratched the surface with these microscopic creatures but it does give you a sense of just how diverse life is and an insight into evolutionary processes that have enabled each species to develop their own niche in the world. It also makes you aware of the beauty of these creatures and gives me a sense of wonder about the world around us. Seeing it for yourself is much better than just looking at video clips and has given me a whole world to explore.
Bears in Billingham
I consider myself curious about the natural world and I am always wanting to know more about the world around us. My natural history interests are wide and varied with the only constraint being time to learn more.
As I intend to take early retirement during 2013 and maybe start to indulge myself with new branches of study with this in mind I purchased something I have always wanted a microscope. I felt to become a true naturalist I needed one. I was very fortunate to find a very good almost new one on eBay during the summer of 2012.
Armed with my new instrument I set about finding a much as I could about this inner world. A very good place to start was the Internet. Before the Internet which younger people see as vital and cannot remember a world before BC (before computers). However, I feel that if Charles Darwin was alive today he would have loved the Internet as a massive resource base to find out and communicate with people from around the world as Darwin did in his time as he spent many hours writing letters to people around the globe.
Here is my microscope with the camera clamp used to obtain the still and movie images.