(from Pinterest, original not found) Electron scanning microscope image of bacteriophage
Viruses take the prize for being not only the smallest biological entities in the ocean, but also the most numerous. There are approximately 10 mission viruses in every drop of surface seawater (futurity.org). They are equal opportunity - it is thought that every animal in the ocean has at least one or two viruses to infect them. Even bacteria have their own viruses, which I thought was a bit of karma. I picture a bacteria giving an infection, and then it gets a little tiny cold from a virus. Serves it right. However, unlike our current viral challenges of COVID, having viruses in the ocean is not all downside. Viruses do their job of keeping ecosystems in balance in the ocean by slowing down rapidly increasing populations of bacteria, and releasing nutrients back into the ocean. If you remember from high school biology, a virus infects a cell, takes over it’s machinery to make proteins and shanghais it to instead produce a ton of new viruses. The cell eventually blows up (lyses) and releases all the newly made viruses (and nutrient bits of the cell) to go on and infect other cells. Turns out the viruses can also pick up bits of the DNA from the cell they blew up and transfer them to the next cell they infect. If they don’t kill that cell, the DNA can incorporate itself and thus contribute to evolution. This is without even bothering with the whole egg and gamete way of passing down genes. This is appropriately called Horizontal Gene Transfer, and is really common. It does tend to muddy the waters when geneticists try to trace the path of genes they are finding in a particular animal.
There are many different shapes or morphs of viruses. We are all really aware of the spherical shape of the Coronavirus from pictures. My favorite shape is the complex shape of the bacteriophage. It looks for all the world just like a microscopic space ship lander. Imagine being a bacteria and having this thing land on you and inject its alien DNA in order to take over your body and then blow you to oblivion. Great material for a horror flick! (correction - they don’t literally blow up, just tear open, but I just love that image!)
The other freaky thing about viruses is that there is debate whether they are even alive. The usual answer to this question from scientists is that viruses are not alive, “because they do not complete all of the seven life processes: Movement, Respiration, Sensitivity, Nutrition, Excretion, Reproduction and Growth. Viruses can’t move, grow (they don’t divide), convert nutrients into energy or excrete waste products. But viruses certainly reproduce….”(from BBC Bitesize)
So, next time you are in the ocean you may think twice about how many viruses you are swallowing accidentally. But fear not, very few of them are generally ones that infect humans. On the other hand, if you consider yourself a bacterium…
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