Deadly Air

About two billion years ago, a deadly case of air pollution threatened to wipe out most life on Earth. The poison gas was released into the atmosphere by photosynthetic single-celled life forms like those in the picture---cyanobacteria. (Photosynthesis is the name of the process some single celled creatures and all plants use to turn sunlight into a form of energy they can use… carbohydrates for instance).

The deadly gas has a familiar name--- OXYGEN.

Oxygen? We need that stuff don’t we? Yes we do and so does most life. Without it we would perish in minutes. So how did oxygen go from a killer gas to a life sustaining one?

First, why was oxygen so dangerous and is it still dangerous? Yes it is because it can produce things called free radicals. Free radicals of oxygen are very aggressive, ripping up molecules used by cells for food, enzymes which cells need to do their work, vitamins, fats and a bunch of other molecules cells need to work properly.

(Free radicals may sound familiar because they have been mentioned a lot in news stories about nutrition along with anti-oxidants. Anti-oxidants are found in many foods, blueberries for instance. They neutralize some of these free radicals before they can do any harm.)

Something had to be done to combat this toxic threat. Fortunately nature is remarkable able to adapt. Billions of years ago, a mutation occurred in a cell’s photosynthesis genes, an error was made yielding two copies of that same gene when the cell divided.

Duplication of a gene is something a cell can exploit. It already has a working copy, so if one of the twins mutates further the cell is probably going to be OK and the new mutation may even be useful. One of the pair mutated further to produce a second kind of photosynthesis. This new process depended on the toxic gas and used up much of the oxygen before it could harm the cell. Talk about a lucky break. Life on the planet would be very different without those fortunate mutations. There are also structures in cells that neutralize oxygen photosynthesis doesn’t need.

This second kind of photosynthesis did not replace the first method, instead they work together. The older method produces the toxic oxygen in a process that splits water into hydrogen and oxygen. (Plants combine carbon from carbon dioxide in the air with the hydrogen to form carbohydrates).

If you are wondering why an organism would produce a toxic gas that could kill it in the first place, here’s the deal. Photosynthetic cells need lots of hydrogen to make carbohydrates and billions of years ago Earth was running out of easily available hydrogen. Photosynthesizing cells solved the problem by splitting a molecule of water, using light energy from the sun, into hydrogen and oxygen. The oxygen was discarded as a waste product into the atmosphere. Minerals in the Earth’s crust combined with the oxygen for a long time, but eventually it could absorb no more and oxygen levels in the air grew to a toxic level. Fortunately the concentration of oxygen grew slowly enough for some organisms to adapt by way of those fortunate mutations.

(There are still many types of bacteria that are killed by exposure to oxygen. You’ve probably used hydrogen peroxide on a wound. Hydrogen peroxide breaks down into water and oxygen. The bubbly stuff you get when you pour it on a cut is you’re right--- oxygen.)

This second kind of photosynthesis not only uses up a dangerously toxic gas, the process using oxygen is also very, very efficient at producing energy. The new and improved cells really took off eventually covering the Earth. Is this lemons into lemonade or what?

Animals also have a process for using up oxygen before it can be harmful as well as tapping into a more efficient means of producing energy. The process is called cellular respiration, not to be confused with breathing. We animals are descended from cells that could exploit oxygen.

So, the next time you take a breath, think about that deadly gas your inhaling and the amazing way life on Earth adapted to —OXYGEN.

Fit to Drink?

I promise this will be the last of the fresh water blogs and I’ll make it short.

Some facts:

40 % US rivers are too polluted for fishing or swimming or aquatic life

46% of US lakes are too polluted for fishing, swimming or aquatic life

Every year approximately 1,200,000,000,000 gallons of untreated sewage, storm water and industrial waste are discharged into US waters.

Each year 250,000,000 people become sick from water related diseases worldwide

Each year about 5,000,000 to 10,000,000 people die of water borne diseases worldwide

Remember we are talking about water, a substance that no living thing can live without. Given that, we should be more careful how we manage it. Fresh water is not only in short supply, but we are making a large percentage of it unusable.

Doesn’t seem like a good idea.

If you would like more information try this link http://www.flowthefilm.com/ a really great documentary on the world of water.

Hold the Salt--Just Water, Please.

Last week I gave the example that if ten full glasses represented all the water on Earth, the fresh water portion would only be about one-third of one of the glasses. And keep in mind we share that with every living thing from bacteria to sequoia trees, plus a good portion of the fresh water we have is frozen at the poles or cruising around in icebergs or flowing along in glaciers. In countries that receive little rain like Sub-Sharan Africa or in states like Nevada or in Southern California, which are really desserts with loads more people than the local water supply can accommodate, at some point the taps will run dry unless a way is found to make fresh water.

Nature does it for us by evaporating water from the oceans. The water vapor goes up the salt stays behind, and eventually the water vapor turns to clouds and fresh water fall from the sky, free.

That worked pretty well until there were too many of us using billions of gallons of fresh water for watering golf courses, lawns, filling swimming pools and billions and billions of gallons a day making stuff, like cars and ironically water bottles.

So what do we do now that we are literally running out of fresh water? Well, we can make fresh water out of sea water just like nature does, but the catch is that it is expensive. Right now the Middle East and Saudi Arabia make up to 70 % of their fresh water from sea water, but then the Saudi’s have plenty of money and lots of cheap oil to run the de-salting plants. (Wonder how they got so rich? A few decades ago the Saudis lived in tents barely making ends meet selling stuff to tourists on the way to Mecca.)

Anyway, there are two main ways water is de-salted---by evaporation or by a process called reverse-osmosis.

The evaporation method is pretty straight forward, you heat sea water, collect the water vapor, cool it and you have liquid fresh water and a really salty brine to get rid of, probably by dumping it back into the ocean, hopefully not on marine organisms that will be injured by high salt concentrations.

The other way is reverse osmosis which is pretty simple too. Basically you have a tank divided by a membrane, a membrane in this case is something that lets water through but not salt, put about 1200 pounds per square inch on the side with the salt water and collect the de-salted water on the other side of the membrane. That requires pumps to provide the pressure and they use energy.

Both methods are expensive, but if you or your industries are thirsty enough you’ll pay what you have to pay.

As of today there are 1200 de-salting plants in the United States with more in the planning stages. What water makers would really like to do is hook up de-salting plants with Nuclear Reactors to supply power. But, the problem here is, that safe as they claim the plants may be, nobody can agree where to store the thousands of tons of radioactive waste for thousands of years.

Not in my backyard, dude.