Working in a microbiology lab, I’ve seen my fair share of bacterial growth curves. They all follow the same pattern: a lag phase or period of adjustment to a particular environment; an exponential phase, or period of rapid growth; a stationary phase, which occurs when nutrients finally become limiting; and finally, a death phase, which occurs when the supply of available nutrients have been exhausted.
I see this trend everyday but this week it seemed less like a typical laboratory observation and more like an ominous microcosmic reflection of our own population growth.
Case in point:
This comparison was prompted by two articles I stumbled across in the lab coffee room over my lunch break this week. The first describes the decline of naturally available helium (via National Geographic, Feb 2011). The second, the decline of readily available phosphorous (via The Scientist).
Fuel shortages and water shortages have both been on the radar for a while, but these were both news to me.
Helium, as it turns out, is mainly collected from natural gas reserves in the great plains of the United States. At one point, the government was stockpiling it but decided to sell off the reserve in the 1990s. (There’s an interesting graph in the paper copy of the magazine); Apparently, by 2015 the helium market will be controlled solely by producers outside North America. So it wont’ be completely gone. However, the fact that we can even deplete our stores of helium is worrisome, given its scientific and medical applications, which include its use in rockets, NMR spectroscopy, MRI scans, deep-sea diving, and geological dating.
The Nobel laureate Robert Richardson argues that helium is vastly undervalued. For instance, he proposes that helium balloons should be sold for $100 instead of $2.
Or maybe we should boycott them altogether? Which would be a little sad, admittedly, but I’d take an MRI scan over a balloon 9 times out of 10.
The second article was perhaps more pressing it its message that human use of elemental phosphorous, particularly in fertilizers, is rapidly depleting natural sources. Our dependance on the key elements of life–such as phosphorous and nitrogen–to support the green revolution means that we are incredibly vulnerable to their disappearance. In effect, we are feeding more people than the earth can naturally support, primarily due to advances in agricultural technology. Things are going to get pretty ugly if and when we run out.
Furthermore, our heavy use of phosphorous is being linked to the development of cancer and other effects of “phosphorous toxicity”.
I’m not going to summarize the rest of the article because it is well-written and deserves to be read in its entirety.
(For instance, the nerdy biochemist in me also enjoyed reading about the cool extremophile bacteria that live in phosphorous-rich and phosphorous-limited environments. There’s one in particular that uses sulphur instead of phosphorous in its cell membrane. Neato! Someone should call NASA. Heh.)
Instead, two final thoughts sparked by my lunch-time readings:
1. As someone interested in the links between environmental and human health, this is further proof to me that the two are fundamentally interconnected. On average, we are far more likely to engage in a debate about health care than environmental concerns because we see one as more immediately relevant to our well-being. One of the great values of molecular biology and biochemistry in my mind has been to build a bridge that links the two. We can now show the effects of elemental phosphorous toxicity in mice and cell lines. Ergo, we can no longer justify the compartmentalization of these issues. (This is a favourite trick in Western thought, as illustrated by our biomedical approach to health care. But that’s another post altogether).
Elections loom on the horizon. This is a prime time to shift the political mindset.
2. Humans are really shitty at being responsible consumers of pretty much everything. Bacterial populations have the same problem and they too face element shortages at some point in their growth. Bacteria are also remarkably adaptable. They can shift their gene expression to make use of waste products and less-desirable resources. (Aside: everyone should be required to observe at least one bacterial growth experiment, IMO. Then maybe birth control would be used more effectively the world over.)
The world is our round-bottomed flask. Eventually we’ll reach our stationary phase too. Will our ingenuity be sufficient?
3. (bonus) This cartoon.