Our oceans and blue carbon ecosystems are under threat.
In this unit, you’ll be introduced to some of the challenges they are facing.
SUB-UNIT 1
OCEAN ACIDIFICATION:
WHAT IS IT AND HOW DOES IT HAPPEN?
You may have heard the term “ocean acidification” before. But what is it exactly and why is it a serious threat to marine life?
Oceans are the biggest carbon sink that we’ve got, absorbing a significant portion of the carbon dioxide (CO2) we are emitting into our atmosphere. However, our oceans don’t just absorb all that CO2, in fact, there is a chemical reaction going on below the surface. This reaction is called Ocean Acidification
Then, what is the issue? Why is this such bad news?
​
Oceans are about 30% more acidic than before the industrial revolution and ocean acidification continues to increase at a rate 10 times faster than any time in the last 55 million years. This has dire consequences for marine life and surrounding ecosystems, such as coral reefs. Knowing that coral reefs are the most biodiverse habitats in the ocean, home to various marine species, ocean acidification is leading to a significant loss of marine life.
Besides this, acidification could leave some species of plankton unable to form their shells. This is extremely concerning as plankton is a foundation of nearly all marine and coastal ecosystems. If these tiny organisms die, everything else that depends on them for food could also start to disappear.
Ocean acidification is a serious problem and is a direct result of increased carbon in the atmosphere. Not only does ocean acidification lead to the death of many sea creatures, but it also affects the valuable ecosystem services that the ocean provides to society, such as fisheries, aquaculture, and shoreline protection.
SUB-UNIT 2
Land-use Conversion
Of all the threats to our oceans and blue carbon ecosystem, land-use conversion is probably the most visually apparent. Land-use conversion, fueled by the drive for economic development has resulted in large-scale destruction and exploitation of mangrove forests around the globe.
​
Mangroves around the world are at risk from land conversion whereby mangroves are cleared for coastal industrial development, residential homes, agricultural land, and aquacultural purposes. Over the last three decades, more than 40% of Indonesia’s mangrove forests have been destroyed, and that’s just Indonesia alone.
Furthermore, timber harvesting on a massive scale is also threatening the existence of mangrove forests. When mangrove forests are cleared on a massive scale, this results in the release of huge amounts of stored carbon, as well as a loss of carbon sequestration capacity. Consequently, this accelerates the rate of global warming and exacerbates the impacts of climate change.
​
Given the importance of mangrove forests to coastal ecosystems, this is really concerning. While the destruction of mangrove forests may result in short-term economic gains for some, the long-term consequences of this destruction far outway benefits.
SUB-UNIT 3
Overfishing
Another threat to our oceans and blue carbon ecosystems is overfishing.
Overfishing occurs when people catch fish faster than the fish populations are able to reproduce, resulting in the depletion of fish stocks. When fish in the ocean are depleted, it creates an imbalance that can disrupt food webs and lead to the loss of important marine life.
​
Besides reducing fish populations, the equipment used in some modern fishing techniques has a negative impact on marine life and habitats. Practices such as bottom trawling, push netting, poison fishing, blast fishing, and shark finning destroy vulnerable habitats such as coral reefs and seagrass beds and kill tons of marine animals many times faster than they are able to reproduce.
How does this happen anyway?
​
Poor management of fisheries and high demand for seafood continue to drive illegal activities, overexploitation, and environmental degradation in the fishing industry.
Around the world, many fisheries are regulated by rules that make the problem worse or have no rules at all. In many cases, difficulties in regulating fishing areas are due to lack of resources and tracking ability. This means some areas are barely monitored, if at all.
Also, fishing areas are largely unprotected – only a little over 7.91% of oceans have been declared as protected areas, and most of these are still open to fishing. This means that areas still can be harmed or depleted.
This is really concerning :(
With oceans taking up over 70% of the Earth, sea creatures and the overall health of marine life are essential for sustaining life elsewhere on the planet. Most developing, coastal communities depend on the fishing industry for their livelihood. When fish and other marine animals disappear, so do jobs and coastal economies.
​
When oceans are bountiful, they play a vital role as a climate regulator. However, if they are emptied, that role is threatened. Therefore, by ending overfishing and destructive fishing techniques, ocean resilience to climate change will increase. Furthermore, healthy marine ecosystems provide a boon to local economies.
SUB-UNIT 4
Plastic Polllution
Plastic. It’s low cost, lightweight, convenient, and has become an indispensable part of our daily lives. However, it’s creating serious long term problems wreaking havoc on our planet and our oceans.
Plastic on average takes 450 years to decompose. This means that the packaging from that pack of instant noodles that your parents had when they were in elementary school is probably still out there, either buried in the ground or floating out at sea.
Every year, it is estimated that 13 million tons of plastic end up in our oceans and makeup 80% of all marine debris, threatening our beaches, oceans, and marine ecosystems.
​
Even if you live hundreds of kilometers away from the coast, the plastic you throw away still has a good chance it will make its way into the sea then end up in the ocean. There are three main reasons for this.
First is when you throw your plastic waste into the bin, it usually gets transported to a landfill. During the transfer, it has a risk of being blown away to the waterways and eventually into the ocean.
​
Third, products that go down the drain. You may be surprised to learn that everyday products such as cotton buds, face wipes, and sanitary items contain plastic. When these products are flushed down the toilet, the plastic in them eventually enters the ocean.
Second, littering! Rainwater and wind carry plastic waste that is dropped in the street into streams and rivers, and through drains which can eventually lead to the ocean. The worst part is some coastal communities still tend to throw their waste, including plastic waste, directly into the sea due to lack of education, bad habits, or lack of alternative waste management solutions.
Once in the ocean, plastic breaks down into tiny pieces called microplastics which can be incredibly damaging to marine life and ecosystems. According to the United Nations, more than 800 species worldwide are affected by marine debris that contains lots of microplastics.
Fish, seabirds, sea turtles, and marine mammals can become entangled in or ingest plastic debris, causing suffocation, digestive problems, starvation, and drowning.
Not only does plastic affect ocean health, human health, coastal tourism as well as food safety and quality, it also poses a hidden threat that is contributing to climate change. The manufacturing process of plastic production and plastic waste itself releases greenhouse gases.
Also, when dumped into the ocean, plastic will get exposed to sunlight and heat, causing it to release greenhouse gases. This leads to a dangerous feedback loop as our climate changes, the planet gets hotter and the plastic breaks down into more methane and ethylene, exacerbating the impacts of climate change.
SUB-UNIT 5
Chemical Pollution
Besides plastic waste, human activities have been pumping alarming amounts of harmful chemicals into our oceans since the Industrial Revolution.
Chemical pollution can be divided into two main categories:
Agricultural pollution
Agricultural pollution mainly comes from the use of fertilizer and pesticides on farms, which ultimately flow into our oceans. Agricultural runoff increases the concentration of chemicals such as nitrogen and phosphorus in the seawater.
This leads to the growth of algal blooms that can be toxic to marine animals and harmful to humans, affecting fisheries and coastal tourism.
Industrial pollution
Industrial pollution takes many forms and includes everything from the extraction of raw materials to the manufacture of finished goods. Pretty much every product we consume in our modern lives produces chemical waste in one form or another.
While some industries such as oil extraction are well-known and obvious polluters, other industries are less obvious and might surprise you. Let’s take a closer look into one such industry, fashion, that pollutes our oceans more than you might realize.
Fashion’s impact on the environment doesn’t stop once our clothes are made.
The first source of pollution comes from the materials used in textile manufacturing. Materials such as polyesters are cheap and frequently used in clothing manufacturing. However, polyester contains microfibres which contain microplastics and when washed in a machine, these microfibres shed and enter our sewage system, further contributing to the ever-increasing amount of plastic waste in our oceans.
Additionally, textile dyeing in the fast fashion industry dumps dangerous chemicals into our oceans. Globally, textile production that uses hazardous chemicals is the second largest polluter of clean water. The polluted water then makes its way into our streams, rivers, seas, and finally oceans. The chemicals are bio-accumulative, meaning they build up inside organisms faster than they can excrete or metabolize them. This has dire consequences for the health of marine life and the ecosystems they live in and support.
Another more obvious source of chemical pollution in our oceans is from oil spills. In addition to the large-scale oil spills that make headlines, there are countless other smaller spills that we do not always hear about. These spills are nearly impossible to clean up and threaten coastal animal and marine life for generations. More crucial to the fight against climate change, oil spills threaten the ability of marine plants and phytoplankton to absorb carbon dioxide produced by human activity.
The last major source of chemical pollution we’ll talk about today comes from mining. Mining both above and below the water provides room for pollutants like mercury to find their way into the marine ecosystem, leading to the death of many marine animals and their habitats. Mercury is widespread in the oceans and can accumulate to high levels in fish such as tuna and swordfish, which are in turn eaten by us humans, causing many health issues for us as well.
It is devastating knowing that there are many pollutants still persist and remain in our oceans, as they are difficult to fully remove. The fate of our seas and oceans is not only in the hands of the government or industry, our individual actions matter too!! In the next unit, you’ll learn more about what we, both as individuals and as a society can do to take action.
Think you've mastered the topics we've covered in this unit?
It's time to put your knowledge to the test!
Answer all the questions correctly and get the certificate!
We would love to watch you progress up. Share your journey with us!
References
Annual reviews | NCBI | ScienceDirect | CIfor | Researchgate | Forestsnews | Youtube | Plastic Garbage Project | ScienceDirect | Conserve Energy Future | World Wildlife | EDF | The Conversation | National Geographic | NRDC | National Geographic | Fashion Revolution | Ocean Conservation Trust | Protected Planet | Nature