Ocean acidification

“Lowest numbers of cod on record”

“Across the United States, changes in our climate and our oceans are having very real and profound effects on communities, businesses, and the natural resources we depend on — including our economically valuable fisheries …” declared a NOAA Fisheries webpage updated in June. “Understanding these changes and measuring their impacts is an important part of NOAA Fisheries’ mission.”

Alaska & Oyster Larvae in an Acidified Ocean

As the Pacific Ocean acidifies—a consequence of carbon emissions—oyster farms off California, Washington State, and British Columbia have struggled to get larvae to grow into seed, the stage when young oysters’ shells have formed. Though scientists are not quite sure why, the water off Southeast Alaska hasn’t seen the same deleterious effects. Now, entrepreneurs and investors are eyeing the state, looking to turn a profit off the short-lived gains of climate change.

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.

Nitrite Pollution Increase in Ocean Water

Researchers have more than once warned of “dead zones” and toxic algal blooms as a consequence of changing climatic conditions. Ocean temperatures are increasing, and this in turn encourages a new set of biochemical processes.

Professor Hollibaugh and a colleague report in the journal Environmental Science and Technology that over the course of eight summers they measured peaks of nitrite, alongside massive increases in the numbers of the microorganisms that produce it, in coastal waters off Georgia.