Deserts and oceans share many commonalities for photographers. While seemingly barren to the inexperienced eye, deserts are havens of highly specialized plants and animals, as well as dramatic and stark vistas. Underwater the same kind of specialization takes place. Tropical reefs are like oases where life gravitates in an otherwise nutrient-poor environment.
At first glance, there appears to be little in common between the open sea and the desert—wet, salty and always in motion versus dry, dusty and slow to change. But once you get past the seemingly obvious differences, it turns out their similarities can be salient. Both are unforgiving terrain if you play the fool. Sand and dust can be as deadly to cameras (and people) as seawater. Both have life forms that can be very difficult to find, let alone approach. Trying to capture an iconic desert scenic can be just as hard as the undersea counterpart. And there’s a sameness to the seclusion one can feel when you’re immersed in their immensity. The isolation inherent in both environments has contributed greatly to the “barren wasteland” description heard often, even today. Wide-open expanses have helped produce everything from vast chemical dumping grounds to nuclear fission laboratories by virtue of their loneliness. Remoteness, in and of itself, also fosters uniqueness in the life forms that try to make a living in these harsh settings. This seems to be true whether you’re animal, vegetable or human.
The animals and plants that have found a way to eke out a living in these unforgiving habitats have had to solve some pretty big problems. The open sea has comparatively little in the way of food sources. While plankton and other underwater organisms are found virtually everywhere across the ocean, their population densities in some areas may not be suitable for adequate sustenance. Also, the seabed is probably miles below the surface, so finding an acceptable place to hide or rest isn’t likely. Just take a look at any floating junk in the open sea, and you’ll find it’s often a magnet for critters looking for refuge. Equally, the harsh dryness and lack of nutrient-rich soils in much of the open-desert regions also offer little incentive for life forms to find a home. Combined with excessive temperature variations between the seasons, and hospitable living conditions are further reduced. Two iconic organisms have achieved significant success in these seemingly unproductive living areas, however—the marine sea jellies (often erroneously called “jelly fish”) and the desert cactus plant.
Sea jellies occupy virtually every niche in the ocean, and most species travel the currents like a leaf in the wind, unable to control their direction to any significant extent. Some species do attach themselves to the bottom substrate, but these are few. As carnivores, they’re opportunistic feeders, and most depend on direct contact with their prey. Living their lives constantly on the move will sooner or later bring them into contact with food. The typical mode of securing lunch is to use venomous cnidocysts to paralyze small animals and then a series of tactile structures to bring the food to their “mouth.” The cnidocysts, or nematocysts, are very small capsules containing toxins and enzymes usually triggered by the contact. They can be located anywhere on the sea jelly, including the bell. Besides an effective tool for capturing their food, the poison is also very good for defense as anyone who has touched the wrong sea jelly washed up on a beach can tell you. Amazingly, the average sea jelly is comprised of 95% water, and yet they exist as females and males with complicated reproduction and intricate tissue development. Many can sense light, have bioluminescence, produce extremely toxic poisons and live for years. They also contribute enormously as food sources for a variety of sea turtles and fishes.