Oceans Issues and Threats – UPSC Geography

Oceans Issues and Threats – Currently our Oceans are facing the following major problems:

  • Over Fishing
  • Predation of Top predators
  • Ocean Acidification
  • Coral Bleaching
  • Ocean Dead Zone
  • Heavy metal Pollution
  • Plastic Pollution

Over Fishing

  • Overfishing is having some serious impacts on our oceans. Not only does it work towards wiping out a species, but also the other species of marine animals that are dependent upon those fish for survival. It’s been shown that overfishing can cause marine animals to starve since we’re taking food from their mouths in too large of numbers for them to be able to get their fill. It is also estimated that most seas already need long term fishing bans if certain species are to recover at all.
  • Apart from it, the processes that are being used for fishing are causing more havoc. We use some pretty destructive methods in how we pull catches, including bottom trawling which destroys seafloor habitat and scoops up many unwanted fish and animals that are tossed aside. We also pull far too many fish to be sustainable, pushing many species to the point of being listed as threatened and endangered.
  • The main reason for overfishing is a sudden increase in the demand for seafood. We are trying to diversify our food sources and recently more impetus is given to seafood citing its health benefits.

Predation of Top predators

  • Sharks are killed in the tens of millions each year, mainly for their fins. 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. The fins are sold as an ingredient for soup. And the waste is extraordinary.
  • Sharks are top-of-the-food-chain predators, which means their reproduction rate 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, it’s usually the case that species lower on the food chain start to overpopulate their habitat, creating a destructive downward spiral of the ecosystem.
  • Whaling is also a major problem pushing the population of a blue whale to the brink.

Ocean Acidification

  • Ocean acidification is no small issue. The basic science behind acidification is that the ocean absorbs CO2 through natural processes, but at the rate at which we’re pumping it into the atmosphere through burning fossil fuels, the ocean’s pH balance is dropping to the point where life within the ocean is having trouble coping.
  • “Ocean acidification is more rapid than ever in the history of the earth and if you look at the pCO2 (partial pressure of carbon dioxide) levels we have reached now, you have to go back 35 million years in time to find the equivalents,” said Jelle Bijma, chair of the EuroCLIMATE program Scientific Committee and a biogeochemist at the Alfred Wegener-Institute Bremerhaven.
  • You need to understand that the pH of ocean water is basic. It is around 8.1 on average. With ocean acidification, the pH is coming slightly less. This does not mean that is has come less than 7. If it gets less than seven, then nothing would survive.

Coral Bleaching

When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white.

Ocean Dead Zone

  • Dead zones are swaths of ocean that don’t support life due to a lack of oxygen, and global warming is a prime suspect for what’s behind the shifts in ocean behavior that cause dead zones. The number of dead zones is growing at an alarming rate, with over 400 known to exist, and the number is expected to grow.
  • Dead zone research underscores the interconnectedness of our planet. It appears that crop biodiversity on land could help prevent dead zones in the ocean by reducing or eliminating the use of fertilizers and pesticides that run off into the open ocean and are part of the cause of dead zones.

Heavy metal Pollution

  • Mercury is the scariest pollutant that is being added to the ocean water. What makes it harmful is the fact that it is ending up on the dinner table. According to estimates, it is about to increase. Almost all coastal countries are facing the problem of mercury poisoning.
  • The long shelf life of mercury allows it to get bioaccumulated and magnified. The main source of mercury in water is Coal based thermal power plants.
  • Under Minamata, convention countries are trying to reduce the use and production of mercury.

Plastic Pollution

  • Large masses of plastic are swirling in the ocean. A giant patch of plastic soup the size of Texas sitting smack dab in the middle of the Pacific Ocean.
  • Many large fishes are choking on plastics. Plastic bags are ingested by the fishes and they get set in the digestive tract. This does not leave any space for the food and fishes die due to starvation.
  • Most of the plastic is finding its way to the ocean through drains and rivers.

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