The world's oceans (which is really one giant ocean), are not doing well. The last 100 years have not been kind to the 71 percent of the Earth's surface covered by water. Human industry has dumped an ever-growing amount of trash and pollution into these waters while ripping out an equally growing amount of fish and sea life. We dirty its waters with our oil spills and choke it with plastics that can persist in an environment for tens of thousands of years. We're disrupting marine ecosystems everywhere and driving countless species towards extinction.

You would think that we'd be more respectful to the ocean, considering that it's a vital source of nutrition for around one-third of people on the planet.

But it's hard to fight against the lure of short-term financial gain. For every step we make in protecting parts of the ocean, it seems we take two steps to drag it back.

You can't fight against what you can't see, and it's really important to know your enemy, so take a little time and familiarize yourself with some of the biggest threats to the ocean.

Fisherman working a net

Photo: crew_agent/Flickr


Humans are too good at catching fish and other sea life. Technologic advancements has given us the ability to scoop up hundreds of miles of floating nets, taking any fish, dolphin, whale, and shark caught within. Large fleets of towering fishing ships spend months at sea harvesting its life, docking with enormous floating factories that take in their catch to freeze and prepare for shipment to shore. History is strewn with historic fish stocks that collapsed after being overfished (and it's continuing today). The problem is exacerbated by the shifting baseline phenomenon — people compare how things are now with how things were when they were young, failing to see that conditions had already degraded far from their natural state by the time they were born. We look at fish stocks now and compare them to how things were in the 1950s, not how they were a thousand years ago before widespread human exploitation.

We once thought that the ocean was too big for our activities to really have an impact. We're seeing all over the world that that supposition is a short-sighted one. As we plunder the ecosystems and marine biospheres with our nets and hooks, we rob ourselves of a future where we can feed ourselves from the sea. We're racing to see who can pull out the last fish.

Dead coral

Dead coral. (Photo: prilfish/Flickr)

Habitat destruction

One of the things that makes protecting the ocean more challenging is that it's hard to see what is going on underneath its waters. We don't see the damage wrought by fish trawlers that drag their nets over the sea floor, scraping up and netting everything in its wide path. We don't see the negative impact of the countless loads of waste and pollution that are dumped into the seas every day. We miss the fields of dying coral and the seagrass and mangrove forests that get whittled away by human development, wind and sea.

Plastic pollution

Photo: blmurch/Flickr


Plastic is — at the same time— one of the greatest and one of the worst of humanity's inventions. It has facilitated a world of technological advancement and proven its utility by becoming virtually indispensable to modern life (look around where you are sitting right now and try to take note of everything made of plastic). But on the flip side, the very durability that makes it so valuable as a building material makes it an ecological monster — an immortal and invulnerable material that resists the pull of time and biodegradation that return most materials back into biologically useful forms.

Our addiction to plastic has not been a good thing for the ocean. As our use of plastic has risen, so too has the amount that has been dumped, blown, tossed, or dropped into the worlds oceans and rivers (which invariably lead to the sea). You might have heard of the Pacific Ocean Garbage Patch, an area in the Pacific Ocean between the West Coast of America and the Hawaiian islands that, due to the circular ocean currents surrounding it, collects and aggregates plastic waste. There are places within the garbage patch that have more plastic than plankton. Sadly, this phenomenon is happening all over the world wherever currents circle. Plastic in the waters leach chemicals and are often mistaken as food by marine wildlife.


Photo: Cliff1066/Flickr

Invasive species

Like their land-based counter-parts, invasive marine species have caused widespread damage to ecosystems all over the world. Species like the lionfish, shore crab, Asian clam, and even the humble starfish have disrupted food webs and driven native marine plants and animals to extinction. The loss of one species in an ecosystem is bad enough, but knock enough out of the picture and entire food webs can collapse. This is happening in oceans all over the globe and shows little sign of slowing down.


Photo: sfPhotocraft/Flickr


OK, so the dangers poised by sunblock pale in comparison to the other four threats on this list, but I'm including it here because most people have no idea that the lotion they put on their skin ahead of a day in the sun can fatally damage coral reefs. A little sunscreen may not sound like a real threat, but when you multiply it by a few tens of millions of swimmers jumping into the oceans every day, you get a substantial amount of sunscreen polluting the waters. What's an eco-conscious swimmer to do? Wear more clothes (think light and airy), buy more ecologically-friendly sunscreen, and buy a wide-brim hat.

Swimming for more stories about oceans? Check these out:

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