Water bodies cover almost 71 percent of the surface of our planet and have played a crucial role in our history; some of the oldest civilizations originated along river channels. Water continues to play a vital role today: it is needed for sustenance, regulation of temperatures, and launching Leonardo Di Caprio’s career.
Despite this important role, 95 percent of current waters remain unexplored. This is partly because of the harsh environment, for which development in robotics and autonomous vehicles are helping deep-sea exploration. Still, it is interesting to note that more people have traveled to space than the deep waters.
Space and underwater exploration are analogous in some ways. They are both challenging and were untouched for a long time, inspiring several mythological stories and characters to humanize the unseen and unknown world. Scary storms were attributed to angry deities, and flying meteorites were considered either lucky or ominous. Both space and underwater studies are resource-hungry and demand considerable funding; hence, research in either of these fields almost always generates a what-is-the-point-of-this-study crowd.
However, one fundamental difference (besides the greater exploration of space compared to underwater) is that the deep sea is the largest existing habitat on earth; it is more habitable than the rainforest. This astonishing biodiversity flourishes despite the extreme pressures, earthquakes, and volcanic eruptions taking place in the darkest depths of the oceans.
Underwater life has to consist of creatures that can survive pressures ranging from 20 atm to more than 1,100 atm. Jellies, worms, bacteria are some examples. Many of these creatures live in areas that have never seen the light of the sun. Chemosynthesis is their key for survival. Several of these deep-sea animals appear strange to mammals like us who are usually exposed to a very skewed sample of living beings. One example of such a life form was the focus of an article two years ago. A type of bacteria was found below the sea floor of the Pacific Ocean (called Pacific gyre). This ancient life was claimed to be at least 1,000 years old, and probably millions of years old, perhaps even dating back to the time of dinosaurs! These bacteria live slowly on a dialed down metabolism, which is their survival strategy in an area so far removed from sunlight and fresh nutrients that it takes millions of years for a thin layer of sediment to form. Hans Roy, who led this study, stated, “If you imagine that a grain of sediment falls on the surface, it will take a thousand years before the next grain will sit on top of it”. The strange disciplined diet of these ancient, buried bacteria was described as follows: “[Bacteria] left the surface 86 million years ago with one lunch box, and they’re still eating out of it. These organisms live so slowly that when we look at it at our own time scale, it’s like suspended animation”.
One scientist, Robert Hazen, finds these bacteria interesting because of their slow rate of reproduction, which has delayed their rate of evolution compared to bacteria in nutrient-rich places. This implies that they may possess more primitive genetic features compared to other bacteria, and are therefore useful for studying fundamental aspects of biochemistry. Andreas Teske, a marine microbiologist, expects that studying their lifestyle can help understand the minimum essential conditions for sustenance of life; this knowledge can be of use to researchers searching for evidence of life beyond Earth.
This brings us back full circle and provides another link between space and water explorations. When we observe light from other planets, we are examining their past. Similarly, going deep into the ocean to collect these ancient microbes with primitive genetic material is comparable to visiting the millions of years old past.
Deep-sea research is compelling because the seas and oceans form an integral part of our biosphere but are largely unexplored. The hydrothermal vents were only discovered in 1977; however, the discovery of the unique organisms and their adaptable mechanisms for survival challenged our definition of life and urged us to look at life beyond our own time scale. Many scientists now believe that majority of life (measured by number) on Earth lives in darkness and processes energy slowly. The survival of the buried bacteria in extreme conditions suggests the endurance of bacteria in discharged material in space (for instance, material ejected by an asteroid impact) and their later deposition on another planet through meteorites (there have been speculations that perhaps life emerged on Mars and came to Earth on a meteorite). In any case, there are exciting prospects for scientists seeking life beyond our planet, especially after witnessing the adaptability of life in underwater creatures.
There are perhaps many more mind-boggling discoveries at the seafloor, waiting to be uncovered. However, until then, during this season of sunny days, overlooking the quiet sea at the beach, we can only consider our inability to imagine the staggering ocean depths teeming with unknown life, unaware of daylight, very much like our limited capacity in imagining the scale of nuclear fusion occurring in the charitable sun.