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The deep ocean has been transformed into a dumping site for radioactive waste, baby bottles, and Spam.
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The deep ocean has been transformed into a dumping site for radioactive waste, baby bottles, and Spam.

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The ocean depths have been traditionally viewed as separate from the rest of the world, a mysterious and unfamiliar place inhabited by foreign beings. This belief is partially due to the challenges of studying it, but it also stems from a deeply ingrained mindset. As noted by writer Robert Macfarlane, humans have always been creatures of the light and sky, often harboring negative feelings towards the spaces beneath our feet which we associate with death, burial, and the unknown. While some may see the “underland” as a site of sacred rituals, the deep sea is more commonly associated with tragedy and disappearance.

While those knowledgeable in traditional methods of navigation may have had a deeper understanding of the ocean, the concept of the deep as an unknowable place was also present in navigational practices. European sailors navigating the Mediterranean, Atlantic, and Indian oceans focused solely on identifying potential dangers like reefs and sandbars, ultimately making the depths of the ocean seem unimportant.

Only in the early 19th century did scientists begin to have a more comprehensive understanding of the depths of the ocean. This was partly due to the expansion of the colonial powers, who had commercial and territorial interests across the globe. As a result, there was a greater need for precise and detailed knowledge of the ocean. Additionally, the experiences of whalers on their journeys into the Atlantic and Pacific oceans revealed the vast depths that whales would frequently dive to, leading to a greater appreciation for the deep ocean.

In the 1850s, there was a growing interest in exploring the depths of the ocean, particularly due to the efforts of British and American entrepreneurs who were laying the first submarine telegraph cables across the Atlantic. This task required a more thorough understanding of the ocean floor and its technical challenges. It wasn’t until the 1870s, when the Challenger expedition became the first to scientifically survey the world’s oceans, that the true extent of the deep ocean was revealed. The expedition discovered depths of over 8,000 meters in the Mariana Trench in the north-west Pacific, which astonished scientists of the time. Additionally, the Challenger also found living organisms, such as tiny shells, at depths of more than 7,000 meters.

Since the Challenger expedition, our knowledge of deep-sea life has been constantly surprising us. One significant discovery is the presence of thriving communities surrounding hydrothermal vents on the ocean floor. These vents occur when cracks in the Earth’s crust allow seawater to mix with magma. Unlike on the surface, where water would evaporate due to the heat, the pressure at the bottom of the ocean keeps the water from boiling. Instead, it is forcefully expelled as a superheated geyser, carrying minerals from the Earth’s mantle. As the water cools, these minerals solidify and create structures that can reach up to dozens of meters tall and can grow 30cm per day.

In 1977, researchers discovered the first hydrothermal vent while exploring the ocean floor 2,500 meters deep in the Galápagos Rift between Ecuador and the Galápagos Islands. The team noticed a sudden rise in temperature near the ocean floor. Upon reviewing photos taken by their submersible, they were astounded to find a diverse and thriving community of organisms. In a subsequent article, scientist Robert Ballard was fascinated by a photograph capturing a temperature anomaly, as the previous image only showed a desolate landscape of fresh lava. However, in the next 13 frames, the lava was covered with numerous white clams and brown mussel shells, a dense and unprecedented accumulation in the deep sea. The scene quickly disappeared from view, and the following 1,500 images once again showed a barren seabed.

Tiny crabs and other sea life live next to a hydrothermal vent on the ocean floor.

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Since the first discovery, over 600 vent sites have been found, all filled with thriving organisms. Unique communities of mussels and other shellfish cling to the hot vents alongside areas of feathery worms and starfish; crabs and shrimp can also be seen darting around, consuming nutrients in the murky water. The abundance of life in these deep, dark oceans is astonishing, especially considering the lack of sunlight for photosynthesis. However, the creatures living around the vents do not rely on sunlight for energy. Instead, they depend on chemosynthetic microbes which can convert the chemicals released by the vents into usable energy.

The discovery of animals living near hydrothermal vents has greatly expanded our knowledge of the types of environments that can sustain life. This has significant implications for the search for life beyond Earth – if organisms can thrive in extreme conditions on our planet, they may also be able to flourish in the icy oceans of moons like Enceladus, which orbits Saturn. This has also challenged previous assumptions about the origin of life on Earth: instead of starting in a shallow pool, it is now believed that life may have begun in the depths of the ancient ocean. In other words, the deep sea may not be a place of death and oblivion, but rather the birthplace of life on our planet.


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There are more areas in the deep sea besides hydrothermal vents that are uncovering surprising variety of living organisms. Dr Tim O’Hara, a marine zoology senior curator at the Melbourne Museum in Australia, has led two expeditions to investigate the ocean floor near the continental margin off the eastern coast of Australia and in the deep waters of the Indian Ocean. These missions were the first to thoroughly study these regions, highlighting the limited knowledge we have of deep-sea environments.

During O’Hara’s trips, they were amazed by the vast amount of biological diversity that their sampling revealed. Even at depths of several kilometers below the surface, the sides of the seamounts were teeming with life, such as corals, crustaceans, and an array of unusual-looking fish. While it will take years for scientists to fully document the species that were discovered on these expeditions, it is estimated that around 30% of them are new to science. This serves as a reminder to O’Hara that even with advanced deep-sea survey techniques, we are only seeing a small portion of a much larger world.

Given the limited nature of this data, it might seem impossible to develop a sophisticated understanding of the distribution of biodiversity in the deep. But incredibly, that is precisely what has begun to emerge out of O’Hara’s research.

A colony of brittle stars on the ocean floor.View image in fullscreen

The story begins with brittle stars, which are related to starfish and use their long, spiny arms to move along the ocean floor. These creatures can be found in deep water and are present in all oceans, with over 2,200 species identified so far. In order to gain a better understanding of the distribution of brittle stars, O’Hara and his team collected genetic material from museums around the globe. This allowed them to create a map of where different species are located. However, as they delved deeper into their research, O’Hara realized that their map not only showed the current distribution of brittle stars, but also provided insights into the evolution of these species and the rate of diversification in different regions of the world.

O’Hara is now working on a far larger project that aims to use genetic analysis to map the history of biodiversity in the oceans over the past 100m years. “My dream is to be able to say: ‘We can see that 20m years ago, all the animals in the Atlantic flooded downwards, and then the circumpolar current swept them around so they populated Tasmania,’ and so on. Because if we can do that, we can make an animated map that shows the swirling movement of biodiversity across tens of millions of years.”


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Could a map alter our perception of the unknown?
It is probable that it would, since it would reveal that the ocean’s depths are not a foreign territory, but intricately connected to all other regions of the earth. Specifically, such a map could counter the habit of using the ocean, especially the deep sea, as a convenient dumping ground for hazardous or costly refuse that is unsuitable for land storage.

During the years following World Wars I and II, the governments of Britain, America, the Soviet Union, Australia, and Canada disposed of outdated chemical weapons by dumping them into the sea, either individually in barrels or by sinking entire ships containing mustard gas and nerve agents like sarin. While public outrage led to an end of this practice in 1972, many fishermen in Europe, the US, and other regions have been hospitalized after unintentionally bringing up solidified chunks of mustard gas or shells containing the dangerous substances in their nets.

The deep depths of the ocean have served as the final resting place for a significant amount of nuclear material. According to a 2019 study, there are approximately 18,000 radioactive objects scattered throughout the Arctic Ocean, many of which were discarded by the Soviet Union. These objects include vessels like the K-27, a 110-meter nuclear submarine that operated with an experimental liquid-metal-cooled reactor and was purposely sunk in 1982 despite its reactor still being intact (although the explosive charges intended to sink it failed to fully detonate and a tugboat had to finish the job). Other examples of these objects are the wreckage of the K-141 Kursk, which sank in the Barents Sea in 2000 during a naval exercise, claiming the lives of all 118 crew members and carrying its reactor and fuel to the ocean floor, and the K-159 attack submarine, which sank while being towed near Murmansk in 2003 with 800kg of used uranium fuel on board. The head of Norway’s Nuclear Safety Authority predicts that it is only a matter of time before these objects start to release their harmful legacy into the ocean, while others have likened the situation to a “slow-motion Chernobyl on the sea floor”.

The Russian K-159 nuclear submarine, which sank in the Barents Sea in 2003 as it was being towed for scrappage.

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Despite the Soviet Union being responsible for the most nuclear waste dumped in the sea, other countries have also contributed. From 1948 to 1982, the British government disposed of almost 70,000 tonnes of nuclear waste in the ocean. The US, Switzerland, Japan, and the Netherlands are among other nations that have also used the sea as a disposal site for radioactive material, though in smaller amounts. While current international agreements forbid the dumping of radioactive material at sea, the British government is considering disposing of 750,000 cubic metres of nuclear waste, including over 100 tonnes of plutonium, beneath the sea floor in Cumbria. This method is seen as a way to keep the waste stable and secure for hundreds of thousands of years, but the 2014 incident of radioactive material leakage from a disposal facility in New Mexico highlights the need for caution when it comes to the promises of the nuclear industry.

The disposal of nuclear waste into the ocean is just a small segment of a larger narrative of recklessness and avarice. Beneath the surface of the deep sea, human refuse in the form of plastics and various items can be found in abundance. This is evident through the Deep-sea Debris Database created by the Japan Agency for Marine-Earth Science and Technology, which records the discovery of items such as tires, fishing nets, sports bags, mannequins, beach balls, and baby bottles scattered across the ocean floor at depths of thousands of meters. In some areas, the quantity of these objects exceeds 300 per square kilometer.

Even the most isolated and inaccessible areas of the ocean are now affected by a significant amount of waste. When Victor Vescovo explored the depths of the Mariana Trench in 2019, he not only discovered new species of amphipods, but also came across a plastic bag and candy wrappers. In a separate expedition in 2016, the US National Oceanic and Atmospheric Administration found a can of Spam at a depth of 4,947 meters in the Mariana Trench.

One cause of concern is the escalating buildup of microplastics deep in the ocean. These tiny pieces can come from large plastic items that have broken down in the water, or from deliberately created plastic beads found in face scrubs and other items. The use of artificial fibers like polar fleece is also contributing to the problem, as they release numerous small filaments every time they are laundered.

Microplastics have infiltrated the upper levels of the ocean’s ecosystem, accumulating in increasingly higher amounts as they are passed up through the food chain. In certain areas of the Pacific, the amount of zooplankton-sized plastic outweighs the amount of actual plankton, resulting in marine animals like whales and birds ingesting significant quantities of microplastics. This can lead to malnutrition and harm to various organs as the microplastics accumulate in their bodies.

Research shows that the amount of plastic present in the upper layers of the sea is significantly lower compared to the amount found in deeper waters. According to studies, a staggering 99.8% of the estimated 11 million tonnes of plastic that enters the ocean annually is believed to sink into deeper depths. Whilst larger pieces of plastic may sink quickly, smaller microplastics take more winding paths. Some are carried downwards by the marine snow, which can be found in the excrement of marine animals, or can become embedded in decomposing pieces of zooplankton and algae. In fact, it is estimated that this process may transport over 400,000 tonnes of plastic into the deep sea every year.


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Is plastic the sole substance that sinks downward? In 2019, a team of Chinese researchers found radioactive carbon-14 resulting from the nuclear bomb detonations from the 1940s and 50s in amphipods dwelling at the base of the Mariana Trench. These particles were not transported by ocean currents, but instead descended with the organic material raining down from the surface. Further investigations have also uncovered radioactive caesium, a product of the Fukushima nuclear catastrophe, in sediment located over 7,000 meters beneath the Japan Trench.

Several substances build up similarly, including persistent organic pollutants like polychlorinated biphenyls (PCBs). PCBs were initially utilized for cooling and insulation in the 1920s, but by the 40s, they were being added to paints, adhesives, PVC coatings on electrical wires, and various other products, causing concern.

The widespread use of PCBs meant large quantities were released into the environment, but the effect of that did not become apparent until the 1950s, when the Danish scientist Sören Jensen found traces of them in pike caught in Sweden. Over the next two years, Jensen detected trace of PCBs everywhere: in fish, in birds – even in the bodies of his wife and daughter.

Since Jensen first found them, PCBs have been prohibited or controlled in numerous nations. However, their presence has not vanished entirely. Instead, as evidenced by the discovery of large amounts in amphipods recovered from the Mariana and Kermadec trenches, they have moved into deeper areas of water.

A Spam tin food container, seen resting at 4,947 metres below the surface in the Mariana Trench in 2016.View image in fullscreen

The exact implications of this are not yet fully comprehended. PCBs are extremely harmful even in small amounts, causing various health issues such as cancer, liver damage, and physical abnormalities in a wide variety of species. They also disrupt hormone levels in fish, birds, and mammals and have been connected to neurological disorders in birds. Due to their affinity for fatty tissues, PCBs accumulate and become more concentrated as they move up the food chain, especially in long-lived and high-level predators such as sharks, seals, and whales. This can lead to mass deaths among dolphins, and has been known to increase mortality rates in whales and dolphins, as high levels of PCBs are transferred to their offspring through their milk. Additionally, PCBs biodegrade very slowly in the absence of sunlight, resulting in their persistence in the deep sea and the bodies of animals for decades or even longer.

Similar to how nuclear waste is slowly breaking down and spreading across the ocean floor, the negative impact of human industry on ocean creatures serves as a constant reminder that the depths of the ocean are not a place to forget, but rather a repository of memories. These memories not only document the recent destruction of the environment, but also reach back far beyond the timeframe of human existence. For example, researchers have learned a great deal about the Earth’s past climate by studying the shells of small, single-celled organisms called foraminifera. These creatures, which are less than a millimetre in size, can be found thriving in the mud on the ocean floor or drifting near the surface with other plankton. As foraminifera die, their shells become layered into the sediment, providing a timeline for scientists to analyze. By examining the different isotopes found within these shells, scientists can reconstruct not only ocean conditions, but also changes in atmospheric carbon dioxide levels, ocean currents, and the evolution of ice caps and plant life over the past 100 million years or more.


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Western science began to understand the actual age of the Earth only 250 years ago. This realization of the vastness of time changed the European belief that humans were at the center of the Earth’s history. Historian Tom Griffiths has compared the impact of this discovery to that of the Copernican and Darwinian revolutions.

To fully understand the vastness and importance of the deep ocean, we must also change the way we think about life on Earth. Although we often assume that terrestrial environments are the defining characteristic of our planet, the truth is actually the opposite. The deep ocean covers the majority of the ocean biosphere and, depending on your method of measurement, occupies nearly 90% of the habitable area on Earth.

Due to increasing evidence of how human actions are impacting the deep ocean, it is no longer feasible to treat it as separate from human activity. Additionally, the idea of exploiting it as a new frontier through projects like deep-sea mining must be reconsidered. Instead, just as the concept of deep time changed society’s perception of our place in Earth’s history, realizing the interconnectedness of the deep with the rest of the planet requires a shift in our understanding of the vastness and intricacy of the biosphere. This, in turn, highlights that the future of not only human life but all life on Earth is intrinsically tied to the deep.

Adapted from Deep Water: the World in the Ocean by James Bradley, published by Scribe UK on 28 March and available at guardianbookshop.co.uk

Source: theguardian.com