For as long as humans have been around, they have seen the oceans as a source of life, and they believed it to be inexhaustible. The oceans have been used for food and transport and, unfortunately, as a huge dumping ground for our trash. We believed, for a long time, that nothing we could ever do would really affect them. Unfortunately, over the past half a century or so, we have learned that we were wrong, and the oceans are at the limit of what they can take. So what are some of the biggest threats facing our oceans?
1. Destructive Overfishing
When we overfish, which means we take too much fish out of the ocean, the cumulative effect is massive. Not only do we lower the amount of fish that we actually try to catch, we destroy their entire ecosystem. Those fish eat, which means other marine life rises, and they are eating, which means even further marine life dies. Around 65% of the large fish is now no longer in our ocean. Additionally, one in every three fish populations have actually collapsed entirely since 1950. Too many boats now try to catch too few fish, and it is destroying the planet.
2. Coastal Pollution
Remember the Deepwater Horizon spill? Most people do. But did you know that was just a 'drop in the ocean' compared to the pollution the Gulf of Mexico faces on a daily basis? The Mississippi River carries uncountable amounts of chemicals into that very same Gulf on a daily basis. These include phosphorus and reactive nitrogen. And it's not just the Mississippi. Agriculture across the world does the same to almost every river, and every river eventually ends in an ocean. This is creating 'ocean dead zones', in which nothing lives. Worst of all is that we know how to stop this, but nobody is actually doing it.
3. Shark Fishing
Sharks are the most important type of predator in the ocean and they are being killed at alarming rates. Worst of all is that the only reason they are being killed is for their fins. In various Asian countries, particularly China, sharks are caught, their fins are sliced off and the still bleeding, alive shark is simply tossed back into the ocean and left to die. Millions of sharks meet this fate, solely so that people can continue to eat shark fin soup. The impact this has on the rest of the ecosystem is tremendous, as the shark is such an important predator. This may be good news for some fish that serve as sharks' food, but it is bad news for the rest of the world, as nature's circle of life has to be maintained.
4. General Pollution
The agricultural pollution previously mentioned is bad, but it is not the only cause of pollution in our oceans. Our own personal behavior is just as bad. We use pesticides and fertilizers, throw everything away and flush everything into the sewage system. Out of sight, out of mind, in other words. Unfortunately, they all end up in the oceans, harming the full marine food chain. And do remember that humans form part of the marine food chain!
A lot of people think commercial whaling stopped around the time of the writings of Moby Dick. Unfortunately, it is still happening. It is believed that just 350 North Atlantic Right Whales exist. The Antarctic Blue Whale has had its population reduced by 99%. The West Pacific Gray Whale is so endangered that there are only about 100 left. This is all due to the fact that whaling still exists, even if it is largely illegal.
Acidification is the hole in the ozone layer of the oceans. As we release gasses into the atmosphere, acids are released into our ocean's waters. This is a very dangerous process, as it makes it impossible for shellfish to reproduce properly, leading to less calcium, and even greater acidity. This process shows that the oceans also suffer from what we do outside of our waters. At this rate, the only organism that will still be able to live in the oceans soon are the jellyfish, and even those may start to struggle.