WE often read and hear about environmental hazards that affect human health but what is happening to the environment of the silent world of waters is not paid its due attention.

Unfortunately, we human beings are on the verge of causing unprecedented damage to the world’s rivers and oceans, and the animals living in them. Pollution, overfishing, oil drilling, illegal poaching, etc., have drastically affected the life and quality of the water on earth. The oceans that used to have variety of life forms before are now seeing many marine species on the verge of extinction; even though some measures have been taken by the United Nations since the last several years to recognise the importance and significance of oceans, it still needs a lot of attention from the world.

In 2008, June 8 as World Oceans Day was officially recognised by the United Nations. The day is an annual observation to honour the world’s oceans, celebrate the products that come from the oceans, such as seafood and marine life, and to appreciate the intrinsic value of oceans. So today let us discover what we are doing to our oceans and what will happen if we don’t stop damaging it and the life it supports.

We all know there are five oceans, Pacific, Atlantic, Indian, Southern and the Arctic oceans. They cover 71 per cent of the Earth’s surface and contain 97 per cent of the planet’s water, yet more than 95 per cent of the underwater world remains unexplored. The ocean and lakes play an integral role in many of the Earth’s systems including climate and weather. How are we damaging the oceans?

Overfishing

OVERFISHING is having serious impacts on our oceans. Not only does it result in wiping out a specie, but also other species of marine animals that are dependent upon those fish for survival. It’s been noted that overfishing can cause marine animals to starve, since we’re taking food meant for them. It is also estimated that most seas already need long-term fishing bans if certain species are to recover at all.

Moreover, the many fishing methods being used extensively are quite destructive, for instance, pulling the catches and bottom trawling destroy sea floor habitat and scoops up many unwanted fish and animals that are later tossed aside, but by that time they are either dead or severely injured.

The Food and Agriculture Organisation estimates that over 70 per cent of the world’s fish species have been entirely exploited or depleted; by capturing fish faster than they can reproduce, we are harming entire ecosystems that interact with those species, from the food they eat to the predators that eat them.

Between 1950 and 2014, Pacific bluefin tuna, sharks and North Atlantic cod were all almost fished to extinction. It is estimated that only between five to 10 per cent of these species remain.

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SHARK finning is killing sharks every year at an alarming rate! It is estimated that 100 to 200 million sharks are annually killed for their fins alone. It is a common practice to catch sharks, cut off their fins and toss them back into the ocean where they are left to die. This practice is mainly for supplying shark fins for shark fin soup, a delicacy in many countries.

Sharks are top-of-the-food-chain predators, which means their rate of reproduction is slow. Their numbers don’t bounce back easily from overfishing. On top of that, their predator status also helps regulate the numbers of other species. When a major predator is taken out of the loop, the species lower on the food chain start to overpopulate their habitat, creating a destructive downward spiral of the ecosystem.

Dead zones, they are growing!

DEAD zones are hypoxic (low-oxygen) areas in the oceans and large lakes, caused by ‘excessive nutrient pollution’ from human activities, coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water.

These dead zones are spots in the sea where life no longer exists. In 1975, there was one documented dead zone, but in 2014, there were more than 500!

Offshore drilling

OFFSHORE drilling continues to be a debate, but it’s clear that proceeding with oil production will only exacerbate the deteriorating condition of our oceans. The use of fossil fuels is the reason our oceans have been heating up and becoming more acidic, but offshore drilling takes the risks even further. When oil is extracted from the ocean floor, other chemicals like mercury, arsenic and lead come up with it. Also, the seismic waves used to find oil harm aquatic mammals and disorient whales.

In 2008, 100 whales had beached themselves as a result of ExxonMobil exploring for oil with these techniques. In 1947, there was just one oil drilling site and in 2014, there were more than 30,000.

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Well the entire ecosystem would collapse; all parts of the food chain are dependent on each other, if one thing goes, it will affect all the others in the chain.

If all fish become extinct then the majority of the ocean’s predators would die out too.

Organisms which are prey to the same animals which eat fish may also be wiped out as predators desperately try to find food. If one species in the food web ceases to exist, one or more members in the rest of the chain could cease to exist too.

It is a domino effect...

INTERRELATIONSHIPS within a food web can be so intricate that a chain of disruptive events can occur when one ecosystem component changes. Polar bears, for example, rely on seals for food. The seal population may decline if Arctic cod, a key food supply for seals, dwindles. Cod eat zooplankton, and zooplankton eats ice algae. If climate change causes sea ice to melt, the ice algae population will drop, creating a cascading effect that reduces the polar bear population.

What you can do to save the ocean?

WITH the summer vacation here, many families would visit the beach or some riverside or lake. Let’s just talk about Karachi’s Clifton beach and everyone will agree that it looks more of a dumping site than a beach! Visitors carelessly throw empty cans, packs, plastic bags and what not, without giving a second thought to the damage they are causing to the shoreline as well as the marine life.

So have fun on the beach, but always clean up before you leave. Explore and appreciate the ocean without interfering with wildlife or removing rocks and corals.

Plastic is poison!

PLASTICS that end up as ocean debris contribute to habitat destruction and entangle and kill tens of thousands of marine animals each year. To limit your impact, carry a reusable water bottle, store food in non-disposable containers, bring your own cloth tote or other reusable bag when shopping, and recycle whenever possible.

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AN unbelievable amount of trash finds its way into the ocean. Animals become easily entangled and trapped in the garbage and it also destroys delicate sea life like coral and sponges.

In addition, sea turtles and dolphins often mistake plastic bags for their favourite foods, like jellyfish and squids, choking them or clogging their digestive system.

If that’s not bad enough, hopefully the bigger-than-Texas trash vortex in the Pacific Ocean and its smaller cousin in the Atlantic will help serve as a wakeup call.

The great pacific garbage patch

PACIFIC garbage patch, also known as the ‘trash vortex’, was discovered by Captain Charles Moore in 1997. Moore was sailing from Hawaii to California after competing in a yachting race. Crossing the North Pacific Subtropical Gyre, Moore and his crew noticed millions of pieces of plastic surrounding his ship.

No one knows how much debris makes up the Great Pacific Garbage Patch as not all trash floats on the surface; denser debris can sink centimetres or even several meters beneath the surface, making the vortex’s area nearly impossible to measure.

About 80 per cent of the debris in the Great Pacific Garbage Patch comes from land-based activities in North America and Asia. Trash from the coast of North America takes about six years to reach the Great Pacific Garbage Patch, while trash from Japan and other Asian countries takes about a year.

The remaining 20 per cent of debris in the trash vortex comes from boaters, offshore oil rigs, and large cargo ships that dump or lose debris directly into the water. The majority of this debris — about 705,000 tonnes — is fishing nets. More unusual items, such as computer monitors and LEGOs, come from dropped shipping containers.

Ocean acidification

THE oceans absorbs as much as one third of the CO2 emitted worldwide, which keeps us cooler but makes the ocean surface much more acidic. This has the effect of limiting calcium carbonate needed by coral, plankton and other marine life that use it to build the skeletal frames and shells that protect them.

As atmospheric carbon dioxide rises, so does that in the ocean. This lowers the pH level in water, making it hard for shelled organisms, such as clams, oysters, corals and some plankton, to live. When these backbones of the ocean die, the repercussions carry throughout the ecosystem. Add that to present estimates of future carbon dioxide levels indicating the ocean could be nearly 150 per cent more acidic by the 2100s, and this is really bad news.

At some point in time, there is a tipping point where the oceans will become too acidic to support life that can’t quickly adjust. In other words, many species are going to be wiped out, from shellfish to corals and the fish that depend on them.

Coral reefs support a huge amount of small sea life, which in turn supports both larger sea life and people, not only for immediate food needs but also in terms of economy. Between 1950 and 2014, half of the coral reefs across the oceans died or suffered serious damage.