Water’s Whispers

Ocean - The Cradle of Life

What caused our existence on this planet? An existential question that man has pondered over ever since he could. Where did we all come from? Did we appear in our current form, as is? What is the birthplace of the first lifeform? Which is the system of which we are all the products? Nature, in all its glory, holds answers to this and more - which man has been, and continues to seek and unravel. Probably, the deep blue waters might whisper the mysteries of life’s origins.

Image Source : European Research Executive Agency, "Protecting Our Ocean and Waters for Future Generations," June 8, 2022; Via - https://rea.ec.europa.eu/news/protecting-our-ocean-and-water-future-generations-2022-06 08_en

Scientists believe that the very waters that murmur the secrets of life’s beginning were once the birthplace of creation. The early oceans are believed to have been bustling laboratories for the precursors of life. These oceans were full of dissolved minerals which served a rich source of inorganic molecules. This, combined with volcanic eruptions and hydrothermal vents on the ocean floor, led to temperature gradients - conditions that may have very well provided a great medium for complex chemistry to take place. Similar conditions were unlikely to have existed on land.

Oceans are believed to have formed around 4 billion years ago, during the Hadean Eon—the earliest chapter in Earth’s geological history. Evidence suggests that life first emerged approximately 3.7 billion years ago, meaning it took nearly 300 million years of oceanic activity before the first signs of life appeared. This strongly reflects that nature toiled for millions of years to make molecules of and for life. Despite all of nature’s force, bringing life into existence was no mean feat. One can only fathom how intense nature’s early turmoils must have been to birth the very first molecule of life!

However, these primordial oceans were prebiotic and vastly different from the oceans we know of today; they were reactive and electrically charged environments - full of potential for chemical reactions of all sorts to occur. In such environments, the basic building blocks of life such as amino acids, nucleic acids are believed to have formed.

This line of reasoning was proven correct with the Miller–Urey experiment in 1953 where they created the conditions that might have prevailed in the early epochs of earth and built an apparatus to circulate methane, ammonia, water, and hydrogen gas past an electric discharge [14]. The experiment resulted in the production of amino acids and became groundbreaking for its empirical support of the hypothesis that prebiotic chemistry could give rise to organic molecules essential for life.

Further experimentation gave more concrete evidence to the idea that life could evolve from non-living matter in the oceans. Simple sugars, amino acids and lipids could accumulate in waves and currents, driven by sunlight, heat, or lightning. Over millions of years these molecules might have assembled into self-sealing membranes (protocells). In this way, the sea can be seen as a laboratory: a place where complexity gradually climbed the ladder from chemistry to biology.

An ample scope for deeper reflection stems from a fundamental property of water molecules - their polarity. Life, in its present form, would not have been possible if water molecules were non-polar. Could this very property of water molecules have been a necessary condition for the creation of life in the ocean? Does it warrant further thinking?

While we often dwell on our understanding that water is the only ‘high and mighty’, researchers are exploring the possibility of life’s existence in non-polar solvents. Thanks to its unique physical and chemical properties, water is arguably the most suited solvent for life - as we know it. However, scientists like Steven A Benner have been examining through experimental studies that alternatives - including non-polar or supercritical fluids - could be potential media to support life, albeit with notable constraints. (18) These constraints arise primarily in the case of a possibly flawed assumption that life must conform to earth’s model. Notwithstanding that conjecture, a wider range of liquids become plausible.

To truly question some of the most fundamental notions ingrained in us, one must explore the works of Steven A. Benner and his colleagues—such as Paradoxes in the Origin of Life and Is There a Common Chemical Model for Life in the Universe? For a bold and open defiance of conventional views, a close reading of Benner’s contributions to Nature’s ‘Seeking the Solution’ feature makes for a compelling read. In this, he presents an unflinching, no-holds-barred argument. Benner asserts that RNA could not have formed in water - strongly quashing the long-held belief that RNA, as the initial genetic material, had its birth in the waters.

On an average, a human’s body is composed of 70% water. Why is it that the number is 70 and not 20 or 95? Is 70 arbitrary? At the outset even if it may seem likely so, research into this question has provided explanation on the structural, physiological and evolutionary factors behind this hydration level in living organisms. Collectively, these studies show how the percentage of water is a result of biological optimisation, adding weight to our understanding that water has shaped life, and that life has adapted itself to a percentage of water, and that happens to be at 70% (approximately).

The fact that the earth’s surface is about 70% covered by water and that the human body is, on average, composed of 70% water offers a very striking and profound symbolism. While no definitive scientific evidence links these figures, for it may or may not exist; it does evoke a philosophical undertone. The resemblance is thought-provoking, making one wonder if we humans have echoed the earthly process. Does the numerical similarity reflect a deep, symbolic parallel?

The cell, whose biochemical environment mirrors that of early seawater, reverberates our evolutionary past. In the 19th century, French physician René Quinton, in his work observed deep ionic similarities between blood plasma and the ocean, referring to it as ‘ocean plasma’. It wouldn’t be wrong to say that we carry within us the chemistry of the ancient seas - and that the salty taste of the ocean, quite literally, runs in our blood!

It is for this reason that scientists speculate that life must have originated in the oceans of early earth. Beyond molecules and water, probably the ocean environment also offered crucial conditions for life’s dawn. Compared to land, the early seas provided stability. Water’s high heat capacity smoothed out day–night and seasonal swings yielding a fairly constant temperature in much of the ocean, a gentle cradle for delicate chemistry. The sea also collected Earth’s minerals. Weathering of rocks and constant volcanic and hydrothermal activity filled the water with iron, sulfur, phosphates and other nutrients. In short, the early ocean was a rich “chemical soup.”

It is thus theorized that the first proper lifeforms were formed in the early oceans in the Archean eon, second of the Earth’s four geological time periods - around 3.5 billion years ago. These lifeforms likely appeared in hydrothermal vents, in the form of bacteria that could metabolize the chemically rich water to utilize as a source of energy. These forms of life are found in the deep oceans even today where no rays of sunlight can penetrate. These microbes did not utilize oxygen as it was not a prominent element in the earth’s atmosphere and used sulfur from chemical reactions to power themselves.

Image Source : NOAA Ocean Exploration. ‘Exploring the “Lost City” Hydrothermal Field’, 2023; Via - https://oceanexplorer.noaa.gov/explorations/23lost-cities/welcome.html

It was not until 3.5 billion years ago that the first organism capable of converting sunlight into usable energy evolved - the precursors of cyanobacteria, a unicellular organism [12]. The proliferation of these cyanobacteria, more efficient energy producers, meant that there was a fundamental shift in the composition of the earth’s atmosphere due to their activities. The atmosphere, once rich in methane, carbon dioxide and hydrogen sulfide, was slowly terraformed by these cyanobacteria to increase the amount of oxygen, a byproduct of their respiration.

Single celled organisms that lack nucleus and are primitive - called prokaryotes - would set the stage for more complex forms of life to evolve. These phototrophs eventually became the food source for the first heterotrophs. This environment persisted for about one billion years when the first multicellular organisms are thought to have formed. Endosymbiotic events in nutrient-rich, stable marine settings gave rise to eukaryotes, which later formed simple multicellular colonies (e.g., algae, soft-bodied metazoans) in sunlit shallows. This was proven experimentally by subjecting the unicellular algae Chlamydomonas reinhardtii to pressures that would promote multicellularity, which yielded great results [13]. The first recorded complex life forms appeared around 560 million years ago. They were very different from the creatures which exist today.

Just as a cradle nurtures a baby into infancy and sets it for life ahead, the ocean has cradled the origins of life - nurturing it through its earliest tides, setting it for the evolution that was to come.

It would be more apt to say that it is not merely water in the oceans that helped life thrive on this planet, but the planet as a whole that made it possible. In this vast and seemingly sublime, enigmatic universe, our dear planet stands out as a bastion of life. It graciously hosts all this rich diversity—from trees that tower like skyscrapers to ferocious dinosaurs and the tiniest microorganisms silently performing their tasks. Each life is to be treasured—whether a small mouse, the majestic tiger, bees tirelessly pollinating, phytoplankton fueling ocean ecosystems, blue whales filtering krill, or humans pondering it all. We remain connected to every form of life on Earth, and it is our prerogative to protect our dear planet, a miracle in the grand scheme of the universe, and cherish our brief time here.

Does nature possess its own intelligence? Is the universe aware of itself? Did nature instinctively know that to give rise to life, it had to begin in the waters? Dashavathara, according to Hindu Mythology, begins with the Matsya - the fish form. Is that merely a coincidence or is there more?

As science seeks the secrets of life’s emergence in water, cultures across the globe have long intuited this belief. Worshipping water for its life-giving properties and essentiality for existence is common among most religions, but there are some to go a step beyond - revering water not merely as a sustainer, but rather as the very origin of life itself. With a rich treasure of knowledge in the vedas, the Hindu Philosophy provides one such perspective. The Nasadiya Sukta in the Rigveda, 10.129.3, alludes to a primordial state where everything was water; This verse can be interpreted as : All this was water, enclosed in darkness - an unborn, primeval chaos. Everything was masked by void, concealed by emptiness.

This understanding resonates with ancient Greek philosophy as well. Thales of Miletus, a Greek philosopher in the 6th century, proposed the revolutionary idea that water is arche - the principal and primary substance from which everything originates and ultimately returns to. Astivisarjan, a ritual followed in Hinduism, which is the submergence of cremated ashes in water, very deeply symbolises the reunion of the human body with the elements of nature from which life once emerged.

Similarly, the Surah Al-Anbiya, 21st chapter, verse 3 in the Quran also affirms that all life came from water.

This multi-cultural recognition of water as not just the sustainer but also the originator reinforces the idea and belief that life, in all its forms, must have had its first stirrings in water.

Authors :

Deepika S, Dr. H S Nagaraja

Acknowledgements :

The authors acknowledge the contributions of Akarsh B, Science Communication Intern for research support and content inputs during the development of this article.

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