by Shane L. Larson
By the middle of the 17th century, Europe was emerging from the cloister of medieval thought, in a renaissance of human intellectualism known today as the Age of Enlightenment. In 1784, Immanuel Kant wrote that the Age represented “Mankind’s final coming of age, the emancipation of the human consciousness from an immature state of ignorance and error.” The methods and philosophy of science as we know it today emerged from this era; the printing of books had become common place, allowing knowledge to be recorded, preserved, and spread; exploration of the natural world and the Earth itself was encouraged for political as well as scientific reasons.
The motif of the age was light. Light was the symbolic enlightenment of the freedom of thought and religion. Light dominated the expansion of scientific thought with the discovery of the telescope and the microscope, tools that expanded the scope of human consciousness by expanding our vision into realms that had seldom been imagined or dreamed of. Light permeated the paintings of the age, suffusing many renowned works of the day, such as Johannes Vermeer’s famous pair of paintings, “The Astronomer” and “The Geographer,” and Rembrandt van Rijn’s “The Storm on the Sea of Galilee.”
Today, as we emerge into the 21st century, the world is poised on the brink of another new age of human consciousness. Using the tools that emerged in the 17th century, the microscope and the telescope, we have engaged in a new age of discovery that amplifies and expands the crux of the Age of Enlightenment: the Copernican Principle. Copernicus’ rejection of an Earth centered Cosmos allowed humankind to see the world anew, to imagine and discover the inner workings of the Universe that have ultimately led to a deeper understanding of our small planet and where it came from. The scientific revolution of the current age is no less profound: we are beginning to understand that we are not alone, and wonder if we as a species are unique. In the last decade, improving telescope technology has led to the discovery and realization that there are other worlds like our own in the Cosmos. The unprecedented ability to gather, categorize, store and retrieve enormous amounts of information has revealed the magnitude of our ignorance about the vast, unexplored realms on Earth that our churning scientific enterprise has yet to penetrate. And ever so slowly, we are discovering that the human race can and does have profound impact on our small blue world. The motif of this age, the central thread that links all these discoveries, is the ubiquitous and innocuous substance that we call water.
Water is the core element of our lives. Water was only one of the four classic Hellenic elements, but we know today that water is special. It is the primary mediator of climate; it is a crucial player in every niche of the Earth’s biosphere; it is one of the dominant shapers of topography and geography on the planet; human populations congregate and concentrate along the planet’s shores and waterways; it is an enormous economic resource and a focal point for political struggles large and small. Of all of these, it is the connections to biology that make water an important player in modern scientific endeavours. Consider the search for other, Earth-like worlds.
For the first time in history, we have the ability to detect and characterize other worlds circling other suns. Since the mid-1990’s, we have discovered and cataloged nearly 500 other worlds, but to date we have yet to find the thing that we most desire: a world that is the size of Earth and at a proximity from its parent star such that liquid water can exist on its surface. The search for water-bearing worlds reflects a profound bias we have: the belief that water is an essential element for any form of life we can imagine. It is an ideal solvent for many of the essential chemicals of life, and is liquid over an enormous range of temperatures making it available for those reactions that we call “life processes.” For hundreds of years, we had speculated that other stars harbored their own huddle of planets. That speculation was smashed by the announcement of a planet around 51 Pegasi in 1995. But the ecstasy of discovery passed quickly, replaced by an obsessive-compulsive search to find worlds like Earth around other suns. Why? The desire to find other Earth-like worlds is driven by a simple and altogether human question: are we alone in the Cosmos?
Ignoring the hidden implications of the question and taking its meaning literally the answer to “are we alone in the Cosmos?” is a resounding NO! In our zeal to look outward, it is easy to forget that we (the human species) share the planet with about 12 million other known species. To put our not-aloneness in context, consider that there are about 6,775,000,000 people on Earth, massing around 100 million tons. By contrast, there are 5,000,000,000,000,000,000,000,000,000,000 microbes on Earth massing about 2 billion tons (about 20x the total mass of the human race). That’s a lot of life besides humans. Even if you ignore bacteria and fungi and microbes and viruses, the number of plant and animal species on the planet exceeds 1.5 million. Virtually all of them are dependent on water for sustaining their life processes. As air-breathing, land-dwelling lifeforms, it is easy to be distracted by other air-breathing, land-dwelling lifeforms like kangaroos, porcupines, tapirs and angora bunnies. But the connections between life and water are framed in rather stark terms if we confine our attention to the waters of Earth.
In 2010 we completed the first decade long survey of life in the world’s oceans. Water covers a full 70.9% of the surface area of the planet, and the Census of Marine Life revealed a startling truth: the waters of our planet harbor an astonishing and vast array of previously uncataloged lifeforms. In October of 2010 the Census released their first Register of Marine Life, cataloging 122,500 species; the project is less than halfway done with the cataloging process. Marine scientists estimate that once the Census is complete, around 230,000 species will have been cataloged, but that this likely only represents about one-quarter of the total species in the world’s oceans. The waters of Earth teem with life, whether we can see it or are aware of it or not.
Looking at the world’s oceans our actions as a single species can have enormous and far-reaching effects on the other lifeforms we share this world with. Consider the Pacific Ocean. The waters of the Pacific (and all the world’s oceans) are in constant motion, circulating and moving water from the depths to the surface and back again, and streaming water from the tropics to the arctic and back again. These vast currents are one of the great cogs in the climate machine that pushes weather around our small blue world. The currents are complex and structured, driven by many physical processes such as wind, Coriolis forces, temperature gradients, and salinity gradients. Often, circular patterns of currents form in ocean basins, known as gyres. The North Pacific Gyre is one of the worlds five major ocean gyres. Spanning an area of 20 million square kilometers from the equator to 50º N latitude, it is the world’s largest ecosystem.
The persistent circulation of the North Pacific Gyre traps and funnels material to its center. Simulations in the late 1980s predicted that material could become trapped in the center of the gyre, and in 1997 Charles Moore discovered the truth while sailing through the gyre — a vast collection of human detritus, mostly plastics, has collected near the center of the North Pacific Gyre. Dubbed the “Pacific Trash Vortex,” media reports have often suggested that the garbage patch covers an area larger than the continental United States. The little scientific voice in the back of all of our minds should immediately voice the question, “how do they know that?” As consumers of information, we must be careful and aware of where scientific information comes from. In 2009 the National Science Foundation funded a survey of the Pacific Trash Vortex which concluded that media reports are greatly exaggerated, and the area is much smaller than the continental United States — it is only twice as large as Texas. Twice as large as Texas. The Pacific Trash Vortex, only a fraction of the detritus that is spilled into the world’s oceans, covers an area of 535,000 square miles, roughly 1/250th of the total ocean surface (1/360th the total surface area of the Earth). The plastic in the vortex degrades into small bits and pieces that mixes vertically in the water, penetrating as deep as 11 kilometers. Human intrusion into the waters of Earth, such as the Pacific Trash Vortex, threaten the biological strata in the waters — tremendous death has been recorded in the central Pacific associated with consumption of plastic at all levels of the food chain in the pelagic zone under the Trash Vortex.
It is easy to document that the trash from our civilization is gathering in the Pacific, but despite our great scientific ability, humans are extraordinarily poor about assessing the connections and consequences associated with simple observations of the world around them. Why should we care if some jellyfish snack on some old photodegraded pop bottles and die as a result? Consider one on many different lines of reasoning: consumption of plastic causes the chemical infrastructure of the plastic to be metabolized and deposited in bodily tissues. Big fish eat small fish, and the chemical elements of the plastics are metabolized by the big fish. This continues on up the food chain. Where does it end? At the top of the food chain, in your dining room. It’s easy to dismiss this, but most of us would not eat a milk jug with our steak and potatoes each night, so why should we eat pieces of milk jugs that have been incorporated into other foods?
There are other threats that like the Pacific Trash Vortex also threaten water ecosystems, such as the desalinization of seawater by ice melt and the subsequent disruption of thermohaline circulation patterns, and the increasing acidification of seawater due to the downdraw of carbon into the water cycle. These are all issues that have their roots in human activities, have far reaching and poorly understood consequences for our race, and are almost certainly going to require human intervention to rectify. The mysteries and predicaments we face hearken back to Rembrandt’s “The Storm on the Sea of Galilee” — a raging apocalypse of a storm looms before us, but like the image of the sailor on the port beam of the ship (purportedly a depiction of Rembrandt himself), one must have the courage to look into the face of the storm itself, look to the light and discover the way forward.
NOTE: This essay began with “The motif of the age was light.” A turn of phrase (and the paraphrasing of the sentence following it) were adapted from COSMOS Ch 6: “Travelers’ Tales”, by Carl Sagan.