Diatoms
Diatoms
Diatoms are found wherever water is found - freshwater or seawater. They are everywhere at Rannoch.
Were they not so small diatoms might be called the elephants in the climate change room.
Many people have never heard of diatoms and yet they may be important to the survival of mankind. If you want to see a diatom you are going to need a microscope. They are very small but there are a lot of them. They live in freshwater and they live in the sea. They are a type of alga and are able to photosynthesise like the higher plants and because they photosynthesise they produce oxygen and use up carbon dioxide. In fact they are more important than all the rainforests of the world put together in capturing carbon dioxide. They are responsible for a massive 23 percent of the carbon cycle. It is anomalous therefore that few have heard of them. When we drive our cars or fly to the other side of the world diatoms are doing their best to absorb the carbon dioxide that we are producing.
As well as being vital components of the food chain and carbon cycle, diatoms are remarkably beautiful when viewed under a microscope. Small is indeed beautiful. They are possessed of silica valves (called a frustule) which are produced in a variety of complex symmetrical and curvaceous shapes. Silica is silicon dioxide and is very tough so that the shells of dead diatoms may last for millions of years as a material called diatomaceous ooze. Silica is the self same material that quartz, sand and glass are made from. It is hard and is near the top of Moh's scale of hardness, which geologist use to help classify minerals. Diatoms that have become a siliceous ooze on the sea bed are useful in determining ancient environmental conditions. The fact that they sink to great depth allows them to take carbon out of the upper environment.
The oceans are a complex ecosystem and it is difficult to predict what will happen when sea temperatures rise. We know that corals are already suffering damage and it is likely that the dominant type of plankton, of which, diatoms are one, will change. If this damages diatoms it will damage their role in carbon capture and sequestration (storage on the sea bed).
You may now be thinking where can I find my nearest diatom? Well, the nearest one may only be feet away in some damp soil or on a wet rock. They could be in a puddle, pond, loch or the sea. Some live in other organisms and some live on the feathers of diving birds. They live in Loch Rannoch and Loch Tummel and Lochaber just as the song says.
Diatoms can be used in forensics - if a person has drowned they will have taken water and the diatoms that the water contained into their lungs and some diatoms will have been absorbed into the body where they can be detected by the pathologist. If the dead body was dumped into water no diatoms will have been absorbed. This method can be used even if the body is somewhat decomposed because the silica shells of the diatoms do not decay. It is also possible to tell by the combination of diatom species if the body is found where the person drowned or if it had moved subsequent to drowning.
It may be possible to use diatoms in nanotechnology because they very reliably produce the same shape of silica shell. It will potentially be possible to artificially select for species that produce the right shape for different purposes. It is proposed that they may have a role in the manufacture of solar cells, semiconductors and in drug delivery.
Naturally you will want to examine some under the microscope. One way to collect them is to gather up some wet mud from a pond, put it into a glass container which is covered with black paper leaving the surface exposed to light. The diatoms will, in a day or two rise to the surface to access the light and can be scooped from here onto a microscope slide.
Diatoms art
A mélange of diatoms.
Creative Commons - credit rovag