Climate Change

Marine Heat Waves Now More Frequent

The study, published Monday in the journal Nature Climate Change, looked at the impact of marine heat waves on the diversity of life in the ocean. From coral reefs to kelp forests to sea grass beds, researchers found that these heat waves were destroying the framework of many ocean ecosystems.

Warming Oceans Threaten Starfish

According to Rebecca Vega Thurber, an associate professor of environmental microbiology at Oregon State University, who was not involved in the study, “What’s really exciting about this paper is the really strong correspondence between this temperature anomaly that occurred during that year when the sea stars started dying.”

Everywhere the warming went, the sunflower stars sickened and died.

The study showed a correlation between warming temperatures and the spread of the disease, not a direct cause. But it corroborates a hypothesis that was initially questioned because the virus that researchers think is responsible also shows up in healthy sea stars.

A Shocking 40% Increase in Ocean Warming

As the oceans continue to heat up, those effects will become more catastrophic, scientists say. Rainier, more powerful storms like Hurricane Harvey in 2017 and Hurricane Florence in 2018 will become more common, and coastlines around the world will flood more frequently. Coral reefs, whose fish populations are sources of food for hundreds of millions of people, will come under increasing stress; a fifth of all corals have already died in the past three years.

A Review of Climate Change & Oceans

Another reason global warming has not been too bad yet is because the ocean absorbs most of the earth’s excess heat. But oceans are warming due to greenhouse gas emissions. According to the National Oceanic and Atmospheric Administration, half of the increase in ocean heat content since 1865 has occurred over the past two decades. Warmer water holds less oxygen, but the respiration rate of animals (except for marine mammals) increases with temperature, so they need more oxygen at the same time that less is available. A warmer ocean has less turnover (vertical water movements), which normally brings nutrient-rich water up from deep water to the plankton that photosynthesize near the surface. With fewer nutrients, they photosynthesize less and animals can’t get enough food.