Why Oceans

“The sea, the great unifier, is man’s only hope. Now, as never before, the old phrase has a literal meaning: we are all in the same boat.”

Jacques Yves Cousteau

Oceans are the life support system of our planet and humankind. The seas flow over nearly three-quarters of the Earth and hold 97% of the planet’s water. Sea plants, like Posidonia, produce 70% of the oxygen we breathe, that’s every second breath we take. The oceans are home to incredible biodiversity and some of the most massive creatures on earth. Producing more than half of the oxygen in the atmosphere , they also absorb the most carbon from it. No matter where you live in the world, from the mountains to the desert, oceans directly affect your life and the lives of everyone you know.

From the air that you breathe, the water you drink, the food you eat, to the products that keep you warm, safe, informed, and entertained, all can come from or are transported by the ocean. Around 50% of the world’s population lives within the coastal zone, and ocean-based businesses contribute more than $500 billion to the world’s economy.

Historically, we thought that we could never take too much out of the oceans, or put too much waste into it. However, now, the sheer number of people on our overpopulated planet who use and depend on the sea, and the sometimes unwise practices we adopt, have created many problems such as the overfishing, pollution, acidifying oceans, biodiversity loss, and degradation of marine habitats, among others. We now risk the very ecosystems on which our survival so closely depends.

From the powerful quote above, Cousteau’s words ring truer now more than ever.

Today, the oceans and marine life are facing the threat of permanent alteration from a number of sources of pollution, and plastic is among the most significant. Plastic accounts for 60-80% of marine garbage, and in high-density areas, reaches up to 95%.

The reality is that every piece of plastic that has ever been made still exists in one form or another. Even when burned, it breaks down into microscopic, toxic particles. Made from oil, plastic is not a material that our planet can digest.

Recent studies have revealed that corals exposed to plastic showed discernable signs of disease 90% of the time. Plastic, a brittle material, is a magnet for bacteria, including some linked to coral

diseases. In addition, plastics can block light, making corals more susceptible to a disease called black band, which leads to complete tissue degradation.

Take this: corals with plastic on them were 20 times more likely to be diseased than those that were not polluted. Plastic permeates our modern lifestyles but there are simple ways for individuals and

communities to reduce their plastic footprint by choosing to use reusable alternatives to common consumer goods like shopping bags, coffee cups, water bottles, utensils, straws, and more.

Quick Facts

• By 2050, there will be more plastic than fish in the ocean (by weight).
• At least eight million tons of plastic leak into the ocean each year.
• Every piece of plastic ever created still exists in some shape or form.
• 95% of plastic in the ocean comes from land

There are many areas of the oceans that are suffering from human made habitat destruction, but coastal areas are disproportionately affected. As the global population grows, coastal land use and development increases.

With development come far-reaching impacts on coastal ecosystems and the species dependent on them. Coastal areas are home to over 90% of all marine species, but we are losing these habitats at an alarming rate.

Coastal habitats include estuaries, marshes, mangrove ecosystems, seagrass, and coral reefs. These habitats serve as nurseries, breeding grounds, feeding spots, and the destruction of these habitats inflict repercussions to dependent species.

Coastal development linked to human settlements, industry, aquaculture, or infrastructure can cause severe impacts on nearshore ecosystems. The impacts of coastal development are both direct (e.g., in the form of landfilling, dredging, coral and sand mining for construction) and indirect, such as from increased run-off and erosion of sediment and pollutants.

Quick Facts

• Coastal areas are some of the most productive and biologically diverse on the planet.
• Humans prefer living near water. 40% of the world’s population lives within 100 km (62 mi) of the coast, taking a significant toll on ecosystems and species.
• Coastal development impacts include pollution, erosion, habitat destruction, and the creation of dead zones.

93% of the excess heat generated by human activities via the greenhouse effect is absorbed by the ocean, thus mitigating the increase in temperature of the atmosphere. This heat absorption causes a slight warming of the ocean which can be detected as deeply as seven hundred meters below sea level. It has now reached the deep sea in the polar regions and is spreading to all ocean basins. Considering the volume of the ocean, this represents a significant amount of heat!

However, even if greenhouse gas emissions ceased today, the effects of the increasing ocean temperature would continue for several decades.

Increasing ocean temperatures affect marine species and ecosystems, causing coral bleaching and the loss of breeding grounds for marine fishes and mammals. Ice melt and sea level rise are two additional crucial consequences of warming sea water.

Rising ocean temperatures also affect the benefits humans derive from the ocean – threatening food security, increasing the prevalence of diseases and causing more extreme weather events and the loss of coastal protection.

Quick Facts

• The ocean has absorbed over 90% of the excess heat trapped by greenhouse gases in the atmosphere since the 1970s.
• Ocean warming affects fish stocks and crop yields, and leads to more extreme weather events and increased risk from water-borne diseases, affecting humans directly.

For more than 200 years, or since the industrial revolution, the concentration of carbon dioxide (CO2) in the atmosphere has increased due to the burning of fossil fuels and land use change. The ocean absorbs about 30% of the CO2 that is released in the atmosphere, and as levels of atmospheric CO2 increase, so do the levels in the ocean.

When CO2 is absorbed by seawater, a series of chemical reactions occur resulting in the increased concentration of hydrogen ions. This increase causes the seawater to become more acidic and causes carbonate ions to be relatively less abundant.

Carbonate ions are an essential building block of structures such as sea shells and coral skeletons. Decreases in carbonate ions can make building and maintaining shells and other calcium carbonate structures difficult for calcifying organisms such as oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton.

These changes in ocean chemistry can affect the behavior of non-calcifying organisms as well. Certain fish’s ability to detect predators is decreased in more acidic waters. When these organisms are at risk, the entire food web may also be at risk.

Ocean acidification is affecting the entire world’s oceans, including coastal estuaries and waterways. Many economies are dependent on fish and shellfish, and people worldwide rely on food from the ocean as their primary source of protein.

Quick Facts

• Since the beginning of the Industrial Revolution, the ocean has absorbed approximately one-third of the CO2 we have produced.
• This has caused an increase of 30% in surface ocean acidity.
• If current CO2 emissions continue at this rate, ocean acidity is expected to increase 100-150% more, relative to the beginning of the Industrial Revolution.

The growing impact of human activities is causing a rapid loss of animal and plant biodiversity. Currently, the rate of animal extinction is 1,000 to 10,000 times higher than the natural extinction rate. According to a UN report on the state of the global environment, 25% of the world’s mammals face extinction by the year 2032.

Some researchers believe that the sixth mass extinction event is already underway. A mass extinction, in the paleontological sense, is diagnosed when the pace of extinction is significantly higher than the pace of origination. Over the past 540 million years, five mass extinctions have occurred, during which at least 75% of all animal species were destroyed due to natural causes. However, the threat of extinction today is caused by human made influences including habitat loss, overhunting, overfishing, the spread of invasive species and viruses, pollution, and the frighteningly high expansion rate of the human population.

In the oceans, the rate of biodiversity destruction is cataclysmic. There is a wide range of causes of marine species extinction and endangerment, such as habitat loss, acidification, atmospheric change, and pollution. The most dominant and influential threat, however, is overfishing. Overfishing is reported to be the greatest threat to marine biodiversity in all regions. When the population of a species is reduced, the genetic variation is reduced along with it. This compromises the species’ ability to adapt to new environmental stresses and changes.

Due to the interdependencies between species, the destruction of one can lead to the demise of others. When whole species are wiped out or remain at insignificant population levels, the stability of the entire ecosystem is under threat.

Quick Facts

• Between 1970 and 2012, marine species populations have declined by 49%.
• By 2100, more than half of the world’s marine species may stand on the brink of extinction.
• 60% of the world’s major marine ecosystems have been degraded or are being used unsustainably.
• There are now close to 500 dead zones covering more than 245,000 km2 (94,600 mi2) globally, that’s equivalent to the surface of the United Kingdom.