Cacti are plants that have evolved to become very successful at thriving in extremely arid and poor soil conditions. They come in all shapes and sizes, occupying high, arid mountain ecosystems down to hot valley floors below sea level. They’re relatively new to the biosphere as virtually all cacti live in the Americas and probably have existed “only” for the last 40 million years or so. Their stems have morphed into fleshy succulent storage structures while the leaves have largely formed into spines for protection and to provide shade for itself. They also have a unique form of photosynthesis. It’s called Crassulacean acid metabolism (CAM), which allows the plant to use the carbon dioxide in another chemical form that doesn’t require transpiration to take place during the heat of the day. This capability significantly reduces water loss during the process. Most have shallow root systems for efficient superficial water uptake and can store immense quantities of water within the stems when it suddenly becomes available. In fact, when fully hydrated, over 90 percent of a stem’s composition can be water. Many species have life spans in the hundreds of years. Cacti also are important food contributors for insects, birds, mammals and reptiles who scratch out a desert life.
There’s a whole host of animals and plants that have figured out a way to survive in the barren open sea and the lonely desert vastness; however, if you compare their numbers to healthy coral-reef or lush rain-forest ecologies, the differences will be in orders of magnitude. At the same time, humans, in great numbers, seek out the desolate beauty of places like Death Valley or yearn to cross the Seven Seas and find a deserted tropical island paradise. Of course, it hasn’t always been this way. Many of today’s national parks were once seen as dangerous by people who wanted to get through them as fast as possible so they could get to some promised land. And crossing an ocean was equally arduous, with scores of sea monsters waiting in ambush. While technology has caused the world to shrink and allowed civilization to flourish in less-than-ideal geography, large tracts of the planet are still off the beaten path.
Given to infrequent but brilliant displays of color, this cactus helps fix water in the arid desert landscape
There isn’t a place much lonelier than Bikini Atoll. Lost in the great expanse of the Central Pacific Ocean, for millennia this small group of islands, located in the 750,000-square-mile region known as the Marshall Islands, was suddenly thrust into the nuclear age in July 1946. The local inhabitants were removed “voluntarily,” and ships, equipment, animals and men were brought in as test subjects. Before it all ended in 1954, we threw everything we had in our atomic arsenal at this little atoll. Twenty-six explosions later, virtually all of the life was obliterated, and scores of radioactive isotopes permeated the sands of the seabed and what was left of the islands.
In 2004 and 2006, I spent 54 hours traveling on three airplanes and a boat, crossing nearly 5,000 miles of “empty” ocean, each time to visit Bikini’s sunken ships resting peacefully at the bottom of the lagoon. Their legacy of the Cold War is my good fortune. To see and feel the history of my father’s time before the sea fully reclaims the nuclear fleet and its possessions is a gift. These giants went down fully loaded with fighter planes, munitions, dishes and even personal effects. Every dive is a voyage back in time. On any occasion, there are fewer than 20 people living on the whole atoll, including the guests of the diving operation. And without TV or even reliable e-mail, the rest of the world essentially disappears.
Visiting the islands of Bikini now, you’d never suspect such a malevolent history. It’s an absolutely gorgeous coconut palm-studded landscape with miles and miles of deserted white sand beaches. Nature took pretty much all the nastiness she could dish out, and after 50 years—a blink of an eye in Earth time—she has nearly erased the destruction without our meddling.