We seldom think about the importance of microscopic organisms. Diatoms are essential for life on Earth because they generate 20-30% of the oxygen we breathe. They are single-celled algae with a cell wall made of silica. In March 2022, the National Science Foundation announced the discovery of two unique diatom species in the waters around Hawaii.
Diatoms live in the oceans and waterways. You may be familiar with diatomaceous earth, which has many commercial uses, including pest control in organic gardening. It consists of the empty silica shells that diatoms leave behind. In addition to generating oxygen, diatoms are essential for life as part of the food chain in the oceans.
Like green plants, diatoms need nitrogen to grow. Marine diatoms thrive in nutrient-rich ocean areas such as the Gulf of Mexico. However, the open ocean waters around Hawaii lack significant nitrogen nutrients. Ocean waters contain dissolved nitrogen gas, but the diatoms can’t use it. These two species of diatoms solve that problem by having a symbiotic relationship with nitrogen-fixing cyanobacteria. These bacteria do not contain chlorophyll for photosynthesis, but they can extract nitrogen from ocean water and convert it to ammonia. In turn, the diatoms can use the nitrogen from the ammonia. In a symbiotic relationship, the newly discovered diatom species take the nitrogen-fixing bacteria into their shells to nurture their own personal nitrogen generators.
We have mentioned many symbiotic relationships before, but here is a microscopic one. Diatoms are essential for life because they provide much of the oxygen we breathe. This symbiotic relationship between diatoms and bacteria is another example of God’s wisdom and design for life. Everywhere we look, we see that God has designed and implemented systems that sustain life in all kinds of environments.
Last week (January 13-15), we talked about the electron structures of oxygen and nitrogen and the importance of those elements for life. One additional design feature is the electron orbitals of oxygen and nitrogen, which is the shape of the electron paths around the nucleus.
Electrons do not revolve around the nucleus in simple circles but rather in geometric paths. For example, the oxygen atom has two electrons that orbit the nucleus in a circular pattern. A little further out and at a higher energy level, two more electrons move in a circular path. Oxygen has eight electrons, and the four electrons in the last energy shell, the valence shell, have a different orbital.
In the third energy level, the orbitals of the four electrons have figure-eight paths at right angles to each other. This figure-eight pattern has two electrons isolated from the other two and each at right angles to the other. That arrangement enables the oxygen atom to form an essential polar molecule.
When an oxygen atom combines with two hydrogen atoms by covalent bonding, they form a molecule of water, H2O. The water molecule has the two hydrogen atoms positioned at one end, making it positive, while the other end of the water molecule is negative. This polar structure gives water its unique properties. For example, water expands as it freezes, causing ice to be lighter than the liquid form. Because of that, ice floats on the surface of a lake instead of sinking to the bottom and freezing the entire lake, killing all marine life. The polar nature of water also allows it to dissolve minerals.
With its seven electrons, nitrogen has five valence electrons moving at right angles to each other, allowing it to form critical organic compounds. For example, nitrogen bonds covalently with three hydrogen atoms to form ammonia which has properties very different from water. Nitrogen’s ability to form three bonds makes possible the structure of the DNA in our cells.
This very simplified description of the atomic design of chemistry gives a small glimpse of the wisdom of design God put into the electron orbitals of oxygen and nitrogen. The Master Chemist designed the structures of atoms to allow life to exist in an incredible number of forms and thrive in a wide range of environments.
Oxygen and nitrogen are two of a handful of elemental superstars of life. Without them, life would not be possible. In some ways, these two elements are very similar, but they are also very different.
Oxygen and nitrogen atoms differ in only one proton and one electron. In chemical reactions, the important subatomic particle is the electron, and oxygen has eight while nitrogen has seven. In the last two days, we talked about the difference that one electron makes. Oxygen and nitrogen make up about 99% of our atmosphere, with nitrogen composing nearly three-quarters of our air. So why is nitrogen’s percentage so high compared to oxygen?
As we said previously, the triple bond of a nitrogen molecule requires more than twice as much energy to break as the double bond of an oxygen molecule. The oxygen bond can be broken to allow combustion oxidation and energize our bodies. On the other hand, the nitrogen bond is not easy to break, but plants require nitrogen for photosynthesis and growth. What is the solution?
Lightning breaks the nitrogen bond allowing rain to wash nitrogen to the ground. Plants such as beans, peas, and alfalfa, which we call legumes, have microorganisms on their roots that extract nitrogen from the air. That enriches the soil with nitrogen while providing for the legumes. More than a century ago, scientists found a way to extract nitrogen from the air to produce ammonia. That process enabled fertilizer production, which today allows farmers to produce enough food for the world’s population.
It is not easy to break the nitrogen bond so it can combine with other elements, but with 78% of the atmosphere being nitrogen, there is no shortage. So why is our atmosphere mostly nitrogen? Since it is only about 21% oxygen, wouldn’t it be better to have more oxygen so we could breathe easier? The answer is that nitrogen stability is essential for our safety. Wildfires have been a significant problem in recent years. If the atmosphere consisted of a very high percentage of oxygen, fires would be more common and dangerous. If the atmosphere consisted of 100% oxygen, all it would take is one lightning strike to set the whole planet on fire.
Remarkably, we have the correct percentage of elements in our atmosphere. We have the right amount of oxygen to allow respiration to power our bodies and combustion to power our vehicles and industry and heat our homes. At the same time, we have the right amount of nitrogen to prevent uncontrolled combustion leading to the destruction of life. We have just a small amount of carbon dioxide, which plants need for photosynthesis. Plants use CO2 and generate oxygen to keep the gases in balance. The balance is amazingly precise as long as humans don’t generate enough carbon dioxide to mess it up.
During the dinosaur age, the oxygen level was higher, on the order of around one-third of the atmosphere. That allowed the enormous animals to prepare the Earth for humans. Now we have the precise balance to sustain human life and advanced society. The question is, did the features of oxygen and nitrogen and the balance between them happen by accident, or was it part of an intelligent plan? We think the best explanation is that an intelligent Planner of life created it.
How does a one-electron difference between oxygen and nitrogen allow life to exist on our planet? Why does the correct mix between those two elements in our atmosphere make it possible for us to be here?
Yesterday, we talked about covalent bonding in oxygen and nitrogen. We said that an oxygen atom needs to share two electrons with another oxygen atom to make a stable oxygen molecule. However, nitrogen needs to share three electrons with another nitrogen atom to complete the valence shell and create stability. So how can a single electron difference between oxygen and nitrogen be a big deal?
For oxygen or nitrogen to combine with other elements to form new compounds essential for life, the covalent bond between them must be broken. It takes about double the energy to break the triple bond between two nitrogen atoms as to break the double bond between two oxygen atoms. That means oxygen can be released to form other compounds much more easily. What does it take to break the oxygen bond and combine it with another element? Apply some heat to combustible material, and you will find out. You will get fire, which is a chemical reaction involving rapid oxidation of the burning material. Much slower oxidation occurs when oxygen in your blood combines with nutrients in your body, giving you energy and generating body heat. Another slow form of oxidation is when iron combines with oxygen to form iron oxide, or rust.
If it were not possible to release oxygen from its molecular bond with relative ease, we would not have combustion to heat our homes, run our vehicles, or energize our bodies. Life would not be possible. However, nitrogen bonds are much harder to break, and nitrogen is also essential for life. Tomorrow we will look at how the one-electron difference between oxygen and nitrogen enables life on planet Earth.
Nitrogen and oxygen together make up about 99% of the air we breathe. The vast majority of our atmosphere is nitrogen. Oxygen is ten times as abundant as nitrogen in the universe, but it makes up only about 21 percent of our atmosphere. So, the less common element is the most abundant in our atmosphere. What does that mean to us? The bottom line is that the atmosphere is fine-tuned for life. Let’s examine that more carefully.
An atom of oxygen and an atom of nitrogen differ by only one proton and one electron. That may not seem like much, but it makes a world of difference. Both of those elements form diatomic molecules, meaning that two atoms bond together to make one molecule of oxygen or nitrogen.
Covalent bonding is the chemical bonding of atoms by equal sharing of electrons. Thatbond gives atoms stability in their outer, or valence, electron shells. Atomic stability requires eight valence electrons. The only elements with that number are the so-called “noble gases”–helium, neon, argon, krypton, and radon. For that reason, they are inert, refusing to combine with other elements. All other elements need electrons to complete the octet in their valence shells.
An oxygen atom has six electrons in its valence shell, so it needs to share two electrons to become stable. When an oxygen atom shares two electrons with another oxygen atom, they both become stable. Nitrogen, on the other hand, has only five valence electrons. Therefore, by forming a covalent bond with another nitrogen atom, sharing three electrons, both atoms complete their outer shell. In this way, our atmosphere is made up of stable diatomic oxygen and nitrogen molecules.
However, not all molecules are equally stable. That is where we see the atmosphere is fine-tuned for life. For example, oxygen molecules have a double bond sharing two electrons, but nitrogen atoms have a triple bond sharing three electrons for more stability. That difference may seem insignificant, but it is essential to make life possible. Come back tomorrow when we will explain what a difference it makes.
You can find six elements in the cells of all living things: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. Without all of those elements, life, as we know it, could not exist. Living things require many other elements to perform various functions to survive, but those six elements are the building blocks of living cells. Life depends on those six elements and three interactions.
What do those elements have in common? For one thing, they are all non-metals. More important is that those six elements have stable atoms that are not radioactive. Radioactive decay of the atoms of some elements releases alpha or beta particles, which are destructive to living tissue. When those particles enter living tissue, they cause the release of high-energy particles in the cells. That destroys DNA, causing disease and mutations.
We are exposed to some radiation every day, but the amount is usually small, and our cells have a remarkable ability to repair themselves. If any of the six elements released radiation particles, life could not exist. Why are these six elements so stable? We have to consider the six elements and three interactions.
Three carefully balanced forces or interactions work within every atom to give stability. They are the strong force, the weak force, and the electromagnetic force. The strong force binds protons together in the atomic nucleus. The weak force is responsible for radioactive decay. Electromagnetic interaction between the protons in the nucleus and the electrons holds those electrons in the atomic shell while allowing chemical interactions between elements.
The key to stability is the precise balance between the three forces. A change in the value of any of the three would upset the balance, making our atoms unstable and life impossible. Was it mere luck that caused the delicate balance of those forces? Is it possible that the balance and our existence are just chance accidents? We think a better explanation is that the Creator of the universe carefully designed the six elements and three interactions.
Many years ago in Alaska, I had a discussion with a biologist who was studying the Alaskan soils. His study revolved around the fact that Alaska has very little soil and what it does have is developing. The lack of soil in Alaska has limited plant growth and made the ecology dependent on migrating salmon. Soils are complex mixtures of organic matter, minerals, water, air, and billions of organisms that form over hundreds of years. Good soils are vital for survival. President Franklin D. Roosevelt once said, “A nation that destroys its soils destroys itself.”
Research has shown that plants are designed to “call” for nutrients from the soil. A plant will release molecules called flavonoids, which cause bacteria in the soil to migrate into the plant and form nitrogen nodules on the roots. The nitrogen nodules generate food for the plant. If ample nitrogen is already available for the plant, it will not release the flavonoids.
This “hunger” by plants is vital to understand because many natural and human-caused processes can deplete the soil. Forest and brush fires, hurricanes, pollution, and climate change can deplete soils’ nitrogen content and kill plants. Studies of the giant sequoias in California have shown that the soil under them has twice as many bacteria as the soil under nearby sugar pines. We all know that bacteria influence human health, but bacteria also affect plant health and growth.
As our population increases and world climates change, it will become increasingly important to understand how soil allows us to feed our growing population. God’s design of the Earth includes providing the soils necessary to produce food. Good soils are vital for survival.
One of the many things that make our planet uniquely well designed is the atmosphere. Our atmosphere has the right density to burn up the 10,000 plus meteors that speed into it every year. It’s also dense enough to scatter the cosmic rays and X-rays from space, so we are protected from this deadly radiation by our Earth’s atmospheric design.
Also very important, the atmosphere is thin enough to allow light to penetrate so plants can grow. It contains the proper mix of gasses for all living things to use. There is enough oxygen for us to breathe, but not enough to cause dangerous, uncontrolled combustion. It has the right amount of carbon dioxide to allow plants to live and give us the right amount of the “greenhouse effect.” This proper amount prevents too much heat from radiating off into space, keeping Earth at a temperature that promotes life.
The atmosphere is mostly nitrogen, which is relatively inert, but plants need it to grow. Because nitrogen is inert, it’s released to the soil by bacteria and certain plants, such as legumes or by lightning or tectonic activity. The atmosphere is topped off with a layer of ozone that absorbs ultraviolet energy from the Sun to keep us from being overexposed to the harmful effects of UV rays.
There are many chemical wonders in our world, but few are as important and complex as the chemistry of nitrogen. Nitrogen makes up 78% of our atmosphere. It combines with oxygen to form nitrates and with hydrogen to produce ammonia, both of which are essential for growing our food. Nitrogen fixation, which is how nitrogen gets from what we breathe to what we eat, is an amazing demonstration of design.
First, let us review a little high school chemistry. The atoms of all elements have electrons which give them their properties for forming compounds. The electrons are arranged in pairs with their magnetic poles designed so that in a stable arrangement, one electron’s north pole is matched with its neighboring electron’s south pole. The electrons have various orbitals with different energy levels. The atom is stable and chemically inert if an orbital is filled with all the paired electrons it can hold. For example, neon has 10 electrons. The first two orbitals each have two paired electrons, and the last orbital has six electrons in three pairs. This pairing of electrons makes neon an inert gas which does not combine chemically with other elements.
Nitrogen has an uneven number of seven electrons. So how does nitrogen become chemically stable? The answer is that two nitrogen atoms share three electrons, giving them stability. The two nitrogen atoms bond together to form a diatomic molecule that cannot be easily pulled apart to bond with other elements. How strong is the bonding? To break up a nitrogen molecule into two nitrogen atoms requires temperatures of 400 to 500 degrees Celsius and pressures of 200 atmospheres. So with nitrogen as the dominant element in our atmosphere, the atmospheric gases are stable and inert. Also, nitrogen is not a greenhouse gas that could threaten our temperatures on Earth. How then has God built a system that takes these stable nitrogen molecules and breaks their triple bonds to produce nitrates and ammonia?
If you think this isn’t an important subject, ask yourself where your food comes from? The answer is that 50% of the American diet is produced using artificial fertilizers containing nitrogen, which has been “fixed.” Nitrogen fixation combines that inert gas with oxygen and/or hydrogen to supply the soil with the chemical needed to grow the plants we eat, and which the livestock eat to provide us with meat.
Bacteria accomplish God’s method of nitrogen fixation. The bacteria turn nitrogen into ammonia, which is a nitrogen atom sharing electrons with three hydrogen atoms instead of with another nitrogen atom. Plants known as legumes such as soybeans and peas, as well as bayberry and alder trees, attract bacteria which concentrate in nodules on the plant’s roots. The bacteria turn nitrogen gas into ammonia and nitrates the plants can use. Cyanobacteria in the ocean and cycad plants on the land are also major nitrogen fixers. Scientists are also discovering tropical plants that contribute to the wealth of nitrogen compounds in the soil.
Most of our fertilizers have nitrogen fixed by a method called the Haber-Bosch process. It uses massive amounts of energy to break the triple bonds of nitrogen gas. Producing 500 degrees and 200 atmospheres is expensive, and that is why you pay so much for the fertilizer you use in your garden. God’s methods are free. Scientists are trying to figure out how to recreate God’s nitrogen fixation method to save energy and produce more food.
Many bacteria are beneficial in various ways, and nitrogen fixation is only one of them. This is a great apologetic for God’s wisdom and design in preparing the Earth to provide food for us to eat.
All life forms on planet Earth need nitrates to build proteins and DNA. We get our nitrates from the plants and seeds that we eat. Plants absorb nitrates from the soil through their roots. The nitrates in the soil come from rain that has absorbed nitrates from the air through which it falls. The nitrates in the air come from the action of lightning. Our atmosphere is 78% nitrogen, and lightning takes some of the nitrogen and catalyzes it into a bond with oxygen to make nitrates. That is why we need lightning.
A surprising thing about this complex system is that the lightning is far more abundant than we realize. Lightning strikes the Earth around 1000 times every second. Above the clouds, in the upper atmosphere, there are continuous lightning types that we don’t see from Earth’s surface. They are called elves, sprites, blue jets, and gigantic jets, depending on their color and shape. There is a voltage difference between the ground and the ionosphere, which varies from 200,000 volts to 500,000 volts. Even in fair weather, there is a constant flow of current, which scientists believe is caused by the spinning of Earth’s core. All of this adds up to a total of over three million lightning strikes a day, and each produces nitrates to sustain life. The jet stream carries these nitrates around the planet, providing a natural fertilizer in places where electrical storms rarely occur.