Is Pollution Causing Low Ocean Oxygen Levels?

Scientists are concerned about areas of the Pacific Ocean that have low levels of oxygen in the water. Areas of the ocean around the United States, especially in the states of Washington and Oregon have little or no oxygen in their waters. Sea creatures such as crabs have been found dead in these areas. And while some sea creatures are dying in these low oxygen areas of the ocean, some types of noxious bacteria are thriving in the same low oxygen conditions.

Ocean Oxygen Levels Chart

Oceans have always had areas that have had little to no oxygen in places. Scientists are concerned that these areas are growing in the last few years. Hypoxia, low ocean oxygen levels, has occurred deep in the Atlantic, Pacific, and Indian Oceans for many years. What concerns scientists is that these regions of low oxygen seem to be spreading. Scientists have discovered that ocean oxygen levels are decreasing nearly every year in some areas of the ocean. It is believed that ocean oxygen levels have decreased by about 34 percent in the last 50 years in some areas of the ocean.

Scientists believe that the lessening of oxygen in parts of the ocean is being cause by climate change that is occurring around the world. One study showed that oceans are absorbing greenhouse gases and carbon monoxide, which in turn causes the surface of oceans to become warmer. Some experts say that agricultural runoff and pollution flowing in the Mississippi and Columbia rivers are adding to the dead zones in the Atlantic and Pacific oceans.

In the summer, north winds combine with the Earth’s rotation to push surface water away from the shore, and drive nutrient-rich but low oxygen water to the surface. This process is called upwelling. The opposite, down-welling, occurs when the winds blow south. The balance between upwelling and down-welling in the ocean has changed quite a bit since 2002, and more low oxygen areas are being found closer to shore. It is unknown at this point whether the change in wind and ocean circulation is caused by global warming or by a weather pattern change.

Scientists don’t know with certainty how the lower ocean oxygen levels will affect ocean life. Ocean life living at the bottom of the ocean will most likely be unable to escape the low oxygen levels. Other species living in the ocean may be more able to adjust to the changing oxygen levels and move to higher parts of the ocean. Jellyfish and squid enjoy lower oxygen water and will thrive in it. So for now, scientists keep watching and looking for changes in the ocean’s oxygen levels. They will try to discover exactly what cause’s lower oxygen levels in the ocean, and what the affects may be on ocean life there.