From Cloud Seeds to Lightning-Made Fertilizer

It’s counter-intuitive but true that water vapor has a hard time turning into water droplets without a solid or liquid surface to act as a seed.  Once liquified, water droplets can remain in a supercooled state below the freezing point in the absence of crystallization surfaces. The correct term for this “seed” is a cloud condensation nucleus, unfortunately creating the need for yet another abbreviation (CCN).

In the 1960s and 1970s James Lovelock proposed that aerosol particles which act as cloud-condensation nuclei (CCN) in the marine atmosphere are principally, perhaps almost exclusively, non sea-salt SO42- particles derived from the breakdown and oxidation of an organic compound (dimethyl sulphonio propionate) that algae used to remain isotonic with their saline environment.

The “perhaps almost exclusively” part was unfortunately never substantiated by evidence. A recent review study revealed that dust, sea salt, soot, biological particles such as pollen along with secondary organic aerosols—Lovelock’s non sea-salt SO42- —can all act as CCN. In fact, the ability of all this material to act as cloud seed depends far less on their chemical composition and more on aerosol particle size.

Another important conclusion from the review of the literature involves the impact of human activity on CCN:

Model calculations and observations in remote continental regions consistently suggest that CCN concentrations over the pristine continents were similar to those now prevailing over the remote oceans, suggesting that human activities have modified cloud microphysics more than what is reflected in conventional wisdom.

Lightning photographed by the author on July 27 in Montreal.

Lightning photographed by the author on July 27 in Montreal.

Once the droplets and ice crystals do form, rising droplets in cumulonimbus clouds collide with ice crystals. Electrons are transferred leading to the major static responsible for lightning.

The bolts of lightning, as this Nova video http://www.pbslearningmedia.org/resource/nves.sci.earth.nitrate/lightning-produces-nitrates/ explains are not very thick but are energetic enough to melt sand and break nitrogen’s triple bond. The free nitrogen atoms then attack air’s other main component, oxygen, to form nitrate, which is an important fertilizer.

Although Lovelock’s Gaia hypothesis is not backed up by observations—the algae with its byproduct aren’t single-handedly bioregulating wind patterns and eventual distribution of nutrients in the sea—there is in reality an astounding interplay of geology, biology and climate on our planet. Even in the absence of man, dust from dry lake beds and volcanoes, pollen and organics from land and microscopic sea organisms, respectively, make condensation possible, which then leads to lightning. Finally the latter forms nitrates which fertilize soil and seas,  finding their way into the proteins and genetic material of life.

Aside from highlighting the planet’s interconnections and revealing that divisions between science disciplines are often academic, the Gaia has important philosophical implications.

In Lovelock’s view humanity is peripheral, though dangerous, to the life systems of the planet. Our anthropocentric concern is to preserve the earth as we want it. Lovelock believes that ideas of stewardship of the planet are absurd and dangerous “hubris“: “We’ll never know enough…….. The answer is ’hands off”….Micro-organisms drive the system and we cannot influence them.

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Reasons I Love Chemistry

Love is irrational. Creating a list of reasons why you love your mate will not make your neighbour fall in love with the person . Well— hopefully not! Similarly, my list of reasons for why I love chemistry will probably not make it your lifelong passion, but it might make you respect chemistry a little more, even though the endeavour has often been misused.

1. It’s fun to use chemistry in everyday life. There’s acid in the snow, so neutralize it with lime in the spring. Reinforce the gluten network in pasta with a little lemon to ensure an al dente texture. Extract struvite, a fertilizer made from urine and epsom salts. Use simple calorimetry to estimate the efficiency of a microwave oven. Avoid adding salt to concrete steps. The chloride in it will make them crumble. Keep the same ion away from your car. Chloride is unfortunately great at displacing iron(II) which will accelerate rusting by exposing more elemental iron to oxygen and water. Understanding the chemistry of corrosion motivates me to tediously wash and wax my car especially during North American winters.

2. Chemistry’s experiments are very sensitive to detail. As Primo Levi mentions in The Periodic Table,

One must distrust the almost-the-same, the practically identical, the approximate, the or-even, all surrogates, and all patchwork.

Although accidentally or deliberately changing a little detail will often mess up a good trick,  it also opens the pathway to discovery.

3. Of course, if those accidents occur on too large a scale, people and the environment can get hurt. What originally put me on a chemistry-career path before I turned to teaching was the fact that chemistry can be used to tackle many of the health and ecological problems that are created through a combination of crude science, unsustainable approaches and plain old human nature.

4. Being as fundamental as physics, chemistry is part of the backbone of other sciences: biology, geology, pharmacology, nutrition and so on. A biologist wondering about the origin of life cannot tackle the problem without considering chemiosmosis and chemical kinetics. How does a geologist explain the difference in colour between rubies and emeralds without understanding the impurities’ effects on the ligand field of chromium(III) ion?

On surface of tissue, cocaine blocks sodium channels, affecting voltage of cells and therefore the transmission of signals. (anesthetic effect)

On the surface of tissue, cocaine blocks sodium channels, affecting the voltage of cells and therefore the transmission of signals. (anesthetic effect)

How does a pharmacologist rationalize the stimulating, pleasurable and anesthetic effects of cocaine without considering three separate chemical mechanisms? And eating black beans with rice makes sense because their essential amino acids (methionine and lysine, respectively) complement each other.

5. Questions and concepts about matter inspire experiments, which in turn lead to new ideas. This interplay leads to the evolution of a new language known as chemistry. Most people are indifferent or antagonistic towards chemistry because it is a foreign language to them. And languages are difficult to acquire past a certain age. Yet introduce it too early and chemistry becomes next to impossible to learn because of the abstractions and mathematics required. For those of us who caught on at just the right time in adolescence, we’re lucky to walk on Atkins’ bridge, linking our senses to that imagined world of atoms and molecules. As I write this, compounds from the parsley that I picked from the garden and handed to my wife linger on my fingers. The sensual experience is rich in itself, but it’s even more meaningful if I could relate the volatility to molecular size, which through the kinetic molecular theory affects the speed at which the smells reach my nasal receptors. What happens in the nose, a response elicited by intermolecular bonds with various receptors, is again chemistry.

6. While adding to one’s understanding of the universe, chemistry keeps one humble. Bohr’s model seemed to adequately explain the emission spectrum of hydrogen, but then it turned out that the lines were not as discrete as they seemed. There were sublevels for most of the electron’s energy levels, and you could never really pin down its location with 100% certainty. After decades of quantum mechanics, understanding periodicity (patterns of behaviour in the periodic table of elements) and investigating bonding in metal atoms, no one until recently could understand why gold atoms were so stingy and how they produced their startling colour. Then it was realized that  in select-heavy elements, the acceleration of inner electrons to relativistic speeds affected atomic size and chemical properties. In cases where atoms are not stingy, when atoms engage in a gain and loss of electrons, in so-called oxidation-reduction reactions, things are not as simple as we imagined either. Thanks to the team of Nobelist Henry Taube we know that in certain inorganic exchanges (and, it turns out, in many biochemical ones too),  there is a facilitating bridge for electrons between complex ions or molecules.

7. Understanding chemistry adds to my realisation of how special life and human beings are. On the other hand, fragmented knowledge of the science can lead to disillusioned and silly statements like this one from the 2001 movie Heartbreakers:

There’s no love. It’s the trick of the brain. It’s the combination of chemicals and hormones.

heartbreakersFor starters, hormones are also chemical compounds, which do play some role in erotic love. But no one has any clue of all the mechanisms involved. We know remarkably little about the inner workings of the brain. And what many forget is that new interactions emerge at every level of the organisation of matter. Chemical bonding in all its forms respects the laws of physics. But from studying physics alone, one would never have imagined the three dimensional discrimination our enzymes have for chiral molecules (nonsuperimposable mirror images, like a left and right- handed gloves). You cannot make a banana in the lab even if you have the complete analytical breakdown of every compound in there. Some of the fruit’s properties emerge from its biology—its cellular structure and tissue behaviour, some of which is still active after it’s been picked. Similarly, as the chemistry and the assemblies of neurons in the brain constantly respond to genetics and to interactions with our physical and social environment, new properties emerge. For now and a long time to come, serious novelists, humanists and some everyday people will have a lot more to say about love than chemistry.

A Misleading Ad Involving Chemistry

The ad I will be attacking is an old one. I first saw it in Scientific American in the early 1980s. But I bring it up 35 years later because recently, blogs, tweets, chemistry educational websites and newsletters have been posting graphics of fruit-components, listing them the way ingredients are outlined in store-bought foods. It was exactly the type of image used by that misleading ad. First the recent graphics:

bananaCompounds

from https://jameskennedymonash.wordpress.com/2013/12/12/ingredients-of-an-all-natural-banana/ It also appeared in Chem13News in the past school year.

blueberryCompounds

Before I get critical, I can’t help contain my enthusiasm for discovering through these graphics that the two most common amino acids in both blueberries and bananas are the same: glutamic and aspartic acid. Asparagine is also common in other fruits. http://onlinelibrary.wiley.com/doi/10.1002/jsfa.2740080304/abstract

In most cases the purpose is educational, but especially in the case of the blueberry tweet, the message that one can possibly take away from such graphics is, “Well, a fruit is full of chemical compounds, so I should not be afraid of other chemical components in man-prepared foods.” But what we need to be reminded of is that although most food additives are safe, that’s not the case for all compounds that have ended up in fruit,  prepared foods or in the environment as a result of agriculture, plastics or other sources. Vigilance and research are vital.

So here is the shameless advertisement:orangeMonsanto

All foods, even natural ones, are made up of chemicals. 

Let’s stop using the term “chemical” when we mean additive.  All matter that we know of consists of atoms. Often the atoms form chemical compounds. Otherwise they remain free elements, which are sometimes charged(ions). A fruit has ions, along with a few uncharged atoms and many compounds, most of which are absorbed from the environment (example, water, which incidentally the ad forgets to list as orange’s primary ingredient). It can also include pesticides added by man, compounds with a variety of concentrations and biological properties. Or it can include nitrates and phosphates, which could leach out of soil and lead to eutrophication.  Is it a coincidence that Monsanto chose an orange for this ad at a time when they were feeling pressure from the revelation that the Agent Orange herbicide they had manufactured was contaminated with dioxin?

But natural foods don’t have to list their ingredients.

In fact some argue that markets and grocery stores should be required to list them. Consumers have a right to know, given that fruits are being imported from different geographical areas and that there’s a variety of fertilizing and pest-treating techniques used by growers and industry. In general, there is a growing concern by the American Academy of Pediatrics, among others, that regulatory agencies do not assess the cumulative effect of the ensemble of additives that we are exposed to.

In fact the ordinary orange is a miniature chemical factory.

What a crude, unscientific analogy! Biosynthesis in a fruit, leaf or animal produces far more compounds than a factory with a far more sophisticated blueprint, that’s far more in tune with its environment, and creating far less waste, if any. That’s not to mention that oranges are time-tested to be safe, given that hundreds of generations have been eating them.

And the good old potato contains arsenic among its more than 150 ingredients.

For starters, potatoes concentrate arsenic in their leaves and peels. How much arsenic is contained in the entire potato depends on where it’s grown. The concentration can be elevated due to industrial contamination or from volcanic emissions. Even without the influence of the latter, different soils in the same country can lead to a wide range of arsenic concentration, from 0.07(probably irrelevant) to 1.36mg/kg (of concern) in Bangladesh potatoes.

And man-made foods often provide more nutrition at a lower cost than natural foods.

There’s no evidence for this notion. Many fruits are rich in vitamins and fiber, and despite their moderate sugar content, they have lower glycemic indices than processed counterparts. And the plums and cherries I grow don’t cost me anything except for the indirect cost of bought food-scraps that serve as compost.

Monsanto: Without chemicals, life itself would be impossible.

It’s a slogan used in an attempt to counter the idea that without releasing large quantities of questionable and dangerous compounds into the environment, life would be better off.