The Earth’s Oceans are in Trouble

The Earth’s oceans are in trouble, in large part due to actions made by humankind. The human species has been using the oceans as a food source and a garbage dump for millennia. These direct misuses have taken their toll, but now, global warming is adding new factors to the equation.

Four of the main problems facing the world’s oceans are Acidification, Garbage Patches, Dead Zones, and Over-fishing.

Acidification of the Oceans

The excess CO₂ in the atmosphere is causing chemical changes to the ocean as it absorbs more and more CO₂. These changes are lowering the pH of the water, which in turn lowers the amounts of calcium carbonate in the water. Ocean pH has been lowered by about 30% since the beginning of the industrial revolution. This chemical imbalance can have grave consequences for the planet.

Shellfish and other marine species can not get enough calcium for forming shells and bones. These animals are an important link in the overall food chain, without them, many species will be affected.

Garbage Patches

The most well known of these is the Great Pacific Garbage Patch. It is located between the California coast and Hawaii. However, there are more of these patches located around the world. The rotating ocean currents in these sub-tropical zones form these areas known as “gyres”.

The patches are huge areas filled with floating debris most of which is plastic. Another large component of this detritus is discarded and lost fishing equipment. We’ll talk more about that when we discuss Ghost Fishing.

Dead Zones

Dead Zones are caused by hypoxia which is a reduced level of oxygen in the water. One of the most famous of these zones, the Gulf of Mexico Dead Zone, is located near the US.

Hypoxia is mostly caused by an excess of nutrients in the water from agricultural runoff. These nutrients are consumed by large blooms of algae. When the algae die they sink to the bottom of the ocean and their decomposition by bacteria consumes all the available oxygen.

There are upwards of 400 of these areas spread around the world.

Over-fishing and Ghost fishing

Over-fishing is depleting ocean fisheries very rapidly. Many countries remove too much marine wildlife from the seas in spite of international treaties. Poor countries tend to over-fish in local coastal waters. Richer countries, many times fueled by subsidies and tax breaks, maintain large fishing fleets capable of reaching any part of the globe. Certain fisheries like pacific salmon, tuna, and cod are near collapse.

If this wasn’t enough, “ghost fishing” is taking a heavy toll on sea life. Ghost fishing is what happens when fishing equipment, like nets and long lines, are lost or discarded. The equipment abandoned in the sea continues to trap fish that end up dying without being harvested.

Conclusion

The earth’s oceans are in trouble and that should concern all of us. In future posts we plan to cover in more depth these four threats and others as well.