Will the ocean really be dead in 50 years?

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Will the ocean really be dead in 50 years?


It’s a long one, so for those of you who don’t have enough time, here are the key takeaways.


  • Plastic to outpace fish, poisoning the ocean and climate.
  • Jellyfish boom due to pollution; fishing reforms needed.
  • Climate change creates ocean "dead zones."
  • Smaller fish due to warm, low-oxygen waters.
  • Rising sea levels hit human habitats harder than marine life.
  • Acidic oceans endanger plankton and krill.
  • Seaweed farming: a sustainability game-changer.
  • More than plastic: chemicals, light, noise also harm the sea.
  • Act now for ocean health; collective effort is key. 


Okay let's go.


Our vast expanses of water, key to the success of all life on Earth, are undergoing drastic changes. From ocean conservation efforts struggling to combat overfishing, to the inundation of plastic pollution, the state of our seas is alarming. These aren't isolated issues; they're interconnected problems exacerbated by climate change affecting the ocean's temperature, acidity, and even its oxygen levels.


The key question we explore in this blog is a haunting one: Will the ocean really be dead in 50 years? It's a complex issue that requires collective action from governments, businesses, and individuals alike.


Buying sustainable seafood, reducing our carbon footprint, and recycling are small steps we can all take, but they're just the tip of the melting iceberg.


A damselfish larva after it has ingested microplastic particles. _ Oona Lo%u0308nnstedt
A damselfish larva after it has ingested microplastic particles. Photo: Oona Lönnstedt



There Will be More Plastic Than Fish


The issue of plastic pollution in our oceans is not just a matter of litter; it's a ticking time bomb that severely affects marine life and, by extension, us. As data estimates continue to paint a bleak picture, the need for marine conservation has never been more critical. So how bad is the plastic pollution problem really? Well, it's estimated that by 2050, our oceans could contain more plastic than fish by weight. That's right, more plastic bottles, bags, and microplastics floating around than actual living creatures.


Plastic doesn't just float idly; it actively releases toxins into the water. As plastics break down, they leach harmful chemicals like BPA, which can disrupt hormone systems in marine life and even humans.


But it's not just BPA; plastic debris can absorb other pollutants from the water, such as polychlorinated biphenyls (PCBs), making them poisonous parcels that can wreak havoc on marine ecosystems.


And the effects go beyond the immediate poisoning of marine life. These toxins can accumulate in fish tissues, leading to longer-term health problems for fish populations, which disrupt the entire food chain. Even scarier? These toxic substances can end up in the fish that make it to our dinner plates.


Besides the direct threat to marine life, there's a climate angle too. Plastic production is a highly carbon-intensive process. Then, consider the energy spent on managing plastic waste and the greenhouse gas emissions from plastic that ends up decomposing in the ocean or landfill. In essence, our plastic problem exacerbates climate change.


So, let's bring it home. Why does marine conservation matter in the face of all this plastic pollution? Well, every piece of plastic we keep out of the ocean is one less toxin-releasing entity damaging marine life and contributing to climate change. Initiatives to recycle plastic, use biodegradable materials, and ban single-use plastics are not just environmentally responsible actions but steps to safeguard the future of our planet.


2 Ocean full of plastic, more than fish. Photograph The Ocean Cleanup
Photo: The Ocean Cleanup



A Jellyfish Take-Over


If the idea of oceans teeming with plastic wasn't enough, let's dive into another unsettling trend: rising jellyfish populations. In a strange twist, these gelatinous creatures are benefitting from the polluted and warmer waters that are causing other marine life to suffer. It's like they're playing by different rules, and unfortunately, their gain is at the ecosystem's expense.


So, why are jellyfish populations increasing? One reason is reduced competition from fish. Many fish species are struggling due to a host of environmental pressures, from habitat destruction to, yes, plastic pollution. This creates a vacuum, giving jellyfish more room to thrive. But that's not the whole story. Jellyfish also appear to have a special affinity for the conditions we humans are creating.


Jellyfish are highly adaptive creatures that can survive in less-than-ideal environments, including polluted and warmer waters.


Pollution, particularly from agricultural runoff loaded with nutrients, creates 'dead zones' in oceans where oxygen levels are low. Most marine life can't survive here, but jellyfish can. They're pretty much the poster children for resilience in the face of human-induced environmental changes.


Warmer waters due to climate change are another factor playing into the jellyfish's hands—or tentacles, if you will. Higher temperatures encourage more algal blooms, another low-oxygen environment where jellyfish can prosper. They're opportunists, taking advantage of the conditions that other marine animals find intolerable.


But it's not a hopeless situation; we can turn the tide through sustainable fishing practices. Overfishing has contributed to the decline in fish populations, which indirectly supports the rise in jellyfish. Adopting more sustainable fishing methods will not only help fish populations recover but also restore the balance in marine ecosystems, making them less hospitable to jellyfish.


1 A Jellyfish bloom iStock

A jellyfish bloom in polluted, oxygen-deprived waters. Photo: iStock



The Water Will be Warmer and It Will Hold Less Oxygen


If you've been paying attention to climate change reports, you might have heard that ocean temperatures are rising. This has far-reaching consequences for marine ecosystems. But there's another aspect that gets less attention: as the water gets warmer, it also holds less oxygen. And this dynamic duo of rising temperatures and dropping oxygen levels is causing a host of problems beneath the surface.


Dead zones are areas in the ocean where the water quality has deteriorated to the point where it can't sustain life. With the rise in temperatures and decline in oxygen, these dead zones are becoming more frequent and expansive.


This is bad news for fish, coral reefs, and basically any form of marine life that requires oxygen to survive.


A Glimpse into the Past: What Fossils Tell Us

Paleoclimatology offers valuable insights into the Earth’s climate history. Fossil evidence from ancient sediment layers has revealed instances of similar oceanic conditions with elevated temperatures and low oxygen levels. Such epochs, like the Permian-Triassic event approximately 250 million years ago, were often accompanied by mass extinctions and took thousands of years for ecosystems to recover.


Reduced marine biodiversity and fish populations have a domino effect on global economies, especially in regions heavily reliant on fishing and tourism. According to the Food and Agriculture Organisation (FAO), over 3 billion people rely on fish for almost 20% of their animal protein intake. A collapse in commercial fisheries could jeopardise food security for large swaths of the population. 


 3 gulf-dead-zone-The Gulf Dead Zone, shown in red, is an oxygen-poor area where little marine life survives. In 2010, it spanned 7,776 square miles-IMAGE COURTESY NOAA

The Gulf Dead Zone, shown in red, is an oxygen-poor area where little marine life survives. In 2010, it spanned 7,776 square miles. Photo: NOAA



Our Fish and Chips Will Get Smaller


As ocean temperatures rise and oxygen levels fall, one less-discussed yet significant effect is the reduction in the size of marine animals, including the fish that make up a vital part of human diets and economies. Indeed, our favorite fish and chips could get smaller, and here's why.


Fish are cold-blooded animals, which means their metabolic rates are directly affected by the temperature of their environment. As waters get warmer, metabolic rates accelerate, requiring more oxygen for cellular respiration. But there's a catch—warmer waters hold less dissolved oxygen.


Higher metabolic demand in an oxygen-poor environment means fish have less energy for growth. As a result, they either grow more slowly or, in extreme cases, experience stunted growth.


The Domino Effect: Up the Food Chain

It's not just the fish at the bottom of the food chain that will experience reduced sizes. Predators who rely on these smaller fish for food will also suffer. Smaller prey means less energy intake for predators, which, in turn, will also struggle to grow to their expected sizes. In essence, this isn't just a fish problem; it's an ecosystem problem. Marine mammals like seals and even seabirds that rely on fish could find it increasingly hard to sustain their populations.


The Double Whammy: Climate Change and Overfishing

Climate change alone poses a serious threat to marine life, but when coupled with overfishing, the impact is disastrous.


Overfishing removes the largest individuals from the population. These larger fish are generally the most fertile and capable of laying more eggs, which are vital for replenishing fish stocks.


When they're removed from the equation, not only does it affect the overall fish population, but it also skews the age and size structure of marine communities.


The remaining younger, smaller fish are less fertile and more sensitive to environmental stressors like increased temperature and lower oxygen levels. 


What Does this Mean for Our Plates?

The shrinking size of fish has implications far beyond the ocean. From a culinary perspective, smaller fish means less meat yield and potentially higher costs for consumers. From a nutritional angle, fish are an essential source of protein for billions of people worldwide. A decline in fish size and population could affect food security and even the global economy, given the massive industry built around fishing.


 4 Jack mackerel caught by a Chilean purse seiner, photo Wikipedia

Jack mackerel caught by a Chilean purse seiner. Photo: Wikipedia



Coastlines Will Change


One of the most immediate and visible impacts of climate change is the transformation of our coastlines, primarily due to the melting ice sheets contributing to rising sea levels. This isn't just a topic of academic interest or a problem for future generations; it's a here-and-now issue with both human and ecological ramifications.


Melting Ice Sheets and Rising Sea Levels: A Dire Equation

When we talk about melting ice sheets, we're primarily focusing on the vast expanses of ice in Greenland and Antarctica. These ice sheets hold the majority of Earth's freshwater and act as a kind of "buffer" for sea levels. As the climate warms, these ice sheets are melting at an accelerated rate, contributing to a rise in sea levels globally. This phenomenon is not just an ecological concern but also a ticking time bomb for human settlements along coastlines.


Ironically, while the ocean is the entity rising, it's humans who stand to lose the most from this shift.


Many marine ecosystems have a certain level of adaptability to changing water levels, as they've been doing it for millennia. Salt marshes, for example, can move inland, and coral reefs have some capacity to grow vertically.


Human settlements are far less flexible. Cities built near the coast can't simply "move" in the face of encroaching waters.


We're looking at the potential for millions of climate refugees, massive economic losses, and the obliteration of cultural landmarks.


Shifting Boundaries: When the Coastline Moves Inland

Rising sea levels aren't just a matter of a few feet of beach disappearing. They fundamentally alter the boundary between land and sea. Wetlands may become submerged, affecting both their ecological function and the species that rely on them. Coastal erosion will also accelerate, leading to unstable cliffs and the loss of habitats for birds and other wildlife.


Adapting to Our Changing World

As our coastlines evolve, so too must our strategies for managing these dynamic areas. Long-term planning that takes into account projected sea level rises is essential for any coastal development moving forward. Infrastructure like sea walls and elevated buildings can offer some protection, but they're just band-aid solutions to a much larger, systemic issue that ultimately needs to be addressed through global climate action.



7 Sea levels continue to rise
Photo: Statista
Source: NASA



6 Melting polar ice caps are causing sea levels to rise, putting coastal communities like those in the Philippines at flood risk. Photo PHOTOGRAPH BY GEORGE STEINMETZ _ NATIONAL GEOGRAPHIC

Melting polar ice caps are causing sea levels to rise, putting coastal communities like those in the Philippines at flood risk. Photo Georges Steinmetz / National Geographic



Water Will Become More Acidic


The health of our oceans is closely tied to the atmospheric levels of carbon dioxide. While oceans act as significant carbon sinks, absorbing a sizable amount of the carbon dioxide we produce, this comes at a considerable cost—increasing ocean acidity.


When carbon dioxide (CO2) dissolves in water, it forms carbonic acid. Although the ocean has acted as a buffer against climate change by absorbing about a quarter of human-generated CO2 emissions, this service comes with a hefty price.


The additional carbonic acid tips the ocean's delicate pH balance towards acidity.


This may seem like a small change, but even a modest shift in pH levels can have disastrous effects on marine life.


The Threat to Plankton and Krill: The Base of the Marine Food Web

Among the most vulnerable to these changes in ocean chemistry are microscopic organisms like plankton and krill. They rely on calcium carbonate to form their shells and exoskeletons. However, the increasing acidity compromises the availability of this essential compound, making it difficult for these tiny creatures to survive.


Given their pivotal role at the base of the marine food web, a decline in plankton and krill populations has cascading repercussions throughout the ecosystem.


Consequences for Larger Marine Animals

It’s not just the small fry who are affected. Larger marine animals like fish, whales, and even penguins rely on plankton and krill as primary food sources. With their primary nourishment compromised, these animals face a food scarcity which can lead to reduced fertility, lower survival rates, and dwindling populations. This, in turn, impacts other species that feed on them, perpetuating a vicious cycle that could devastate the biodiversity of our oceans.


The Ripple Effects on Climate and Human Activity

The growing acidity doesn't just stop at the ocean’s edge; it has broad implications for climate regulation and human activity. Oceans are a critical component in Earth's climate system, and a less effective carbon sink could accelerate global warming. Furthermore, with oceanic ecosystems in jeopardy, industries like fishing and tourism, which millions rely on for their livelihood, are at serious risk.


8 Microplastics found in plankton, Cole et al. (2013)

Zooplankton containing microplastic fragments. Photo: Cole et al. (2013)



Farming the Sea


As we grapple with the increasing challenges of climate change and overfishing, the search for sustainable food sources has never been more crucial. In this endeavor, one of the most promising options is as ancient as the ocean itself—seaweed.


Seaweed is not just the stuff you avoid when taking a swim at the beach; it's a highly nutritious plant packed with vitamins, minerals, and even protein.


As a sustainable food source, seaweed has some distinct advantages. It doesn't require freshwater, synthetic fertilisers, or pesticides, making it an eco-friendly choice. Additionally, certain varieties of seaweed, like kelp, are particularly effective at absorbing carbon dioxide, making them a natural ally in the fight against climate change.


Overcoming Challenges in Seaweed Farming

Of course, seaweed farming is not without its hurdles. The process faces challenges ranging from the optimal design of farming structures that can withstand rough ocean conditions, to the best methods for harvesting without damaging the plants or surrounding ecosystems. Research is currently underway to tackle these issues, with advancements in hydrodynamic modelling and biodegradable materials offering promising solutions.


Seaweed's Versatility

Beyond its role as a food source, seaweed also has a variety of other uses, from biofuel production to a base for cosmetics and pharmaceuticals. Its multi-purpose nature makes it not just a solution for sustainable food, but a resource that could have a broader economic impact.


If researchers can successfully address the challenges in seaweed farming, we could be looking at a future where our meals include not just fish from the sea, but plants as well.


With its low environmental footprint, seaweed could play a pivotal role in mitigating some of the challenges we face, from food security to climate change.

 9 NUSA PENIDA, INDONESIA - 2011-06-28 Farmer collecting seaweed plantations at seaweed farm in Nusa Penida, Indonesia

Farmer collecting seaweed plantations at seaweed farm in Nusa Penida, Indonesia. Photo: Shutterstock



Other Pollutants Could Increase


While the scourge of plastic pollution often takes center stage in discussions about ocean health, it's crucial to remember that our seas face a cocktail of other pollutants. Chemicals, light, and even noise are pervasive and growing problems, each with their unique long-term effects on marine life.


The Chemical Soup

Pharmaceuticals, agricultural runoff filled with pesticides, and industrial chemicals are just a few examples of the toxic substances that make their way into our oceans. Unlike plastic, these pollutants are often invisible but far from harmless.


They can accumulate in the tissues of marine animals, disrupting reproductive systems and leading to devastating consequences for ocean ecosystems.


 The Ixtoc I Oil Spill, 1979. 140 millions gallons spilt over the duration of one year. Getty images
The Ixtoc I Oil Spill, 1979. 140 millions gallons spilt over the duration of one year. Photo: Getty images


Night Isn't What It Used to Be: Light Pollution

The bright lights of coastal cities and shipping routes don't stop at the water's edge. They penetrate the ocean, disrupting the natural circadian rhythms of various marine species.


For creatures like sea turtles, which rely on the moonlight to navigate their way to nesting sites, light pollution can lead to disorientation and decreased survival rates for hatchlings.


 Looking Up At A Fullmoon From Underwater. Photo TWmedia
Looking up at a full moon from underwater. Photo: TWmedia


A Symphony of Noise

With the increase in shipping, ocean exploration, and even recreational boating, our oceans have become a cacophony of artificial noise.


Sounds travel four times faster in water than in air, making it difficult for marine animals to communicate, navigate, or even escape predators.


Animals like whales and dolphins, which rely heavily on echolocation, are particularly affected by this acoustic smog.


 A blue whale near an oil platform. Marine animals are increasingly affected by noise pollution. Getty Images
A blue whale near an oil platform. Marine animals are increasingly affected by noise pollution. Photo: Getty Images


Long-term Effects on Marine Life

What makes these pollutants so sinister is their cumulative effect. Chemicals can lead to coral bleaching and endocrine disruption in fish, while light pollution alters feeding patterns and disrupts mating rituals. Noise pollution adds another layer of stress, potentially leading to lower reproduction rates and increased vulnerability to predators.


The combined long-term effects can lead to shrinking populations, disrupted food chains, and ultimately, less resilient marine ecosystems. 


Conclusion: Time is of the Essence—The Ocean Can't Wait


The issues we've outlined, from the rising tide of plastic pollution to the less visible but equally harmful impacts of chemicals, light, and noise, underline a single, urgent message: the time to act is now. Our oceans are not just a distant, separate world; they are a living, breathing part of our global ecosystem, impacting our climate, our food supply, and even the air we breathe.


The Necessity of Swift Action

With problems like climate change causing ocean temperatures to rise and oxygen levels to drop, and pollutants creating inhospitable "dead zones," procrastination is a luxury we can't afford. The changes are already manifesting: smaller fish sizes, shifting coastlines, and disturbed marine food chains are just the tip of the melting iceberg. Every day we delay, these issues compound, leaving a more challenging, perhaps insurmountable, problem for future generations.


The Power of Collective Action

While individual actions—such as reducing plastic use or making sustainable seafood choices—can make a difference, these efforts are akin to a drop in the ocean. The real power to bring about change lies in collective action. This involves businesses adopting more sustainable practices, governments enforcing stricter environmental regulations, and the global community uniting to protect our oceans' long-term health.


Scientific research and technological innovation can offer solutions, from advancements in seaweed farming to breakthroughs in renewable energy that can reduce our reliance on fossil fuels and their associated pollutants. But these solutions will only work if we implement them swiftly and broadly.


A Vision for a Healthy Ocean

A healthy ocean doesn't just mean cleaner water. It means a more stable climate, a richer biodiversity, and a more secure food supply chain for us all. The ocean is not an inexhaustible resource but a fragile system, teetering on the brink of irreversible damage. It will take a concerted, global effort to pull it back from the edge.


In summary, the ocean's plight isn't someone else's problem; it's everyone's problem. The clock is ticking, and the ocean—as vast as it is—doesn't have the luxury of time. As we move forward, let us not forget the vital importance of collective action and the urgency that the situation demands.