Marcia McNutt

The potential impacts of global warming on the surface of the Earth are horrible enough — inundated coastlines, sunken atolls, elimination of species, the spread of tropical disease to the temperate climates. But in the sea, upon which much of Earth's life depends, they could be even more devastating.

Marcia K. McNutt, president and CEO of the Monterey Bay, Calif., Aquarium Research Institute, said the danger to oceans is acidification, caused when carbon dioxide emissions in the atmosphere end up in the ocean and change into carbonic acid.

McNutt is scheduled to give the University of Utah's Frontiers of Science Lecture, speaking on this topic, at 7:30 p.m. on Wednesday. The talk, free to the public, will be held in the Aline Wilmot Skaggs Biology Building Auditorium on the university campus.

"The reason I'm eager to talk to the people in Utah about this is the fact that the conversation on climate change is so focused on the impact on the land side of the planet," she said in a telephone interview. "And yet two-thirds of Earth is covered by ocean."

Most people get their protein from the ocean, she said. If climate change harms fisheries, "that is going to have a very big impact on our ability to harvest protein from the oceans." Also, more than half of the oxygen that we breathe comes from plants that photosynthesize in the oceans, she added.

"So we have to be concerned about any impacts of climate change that affect the ability of those plants to convert carbon dioxide back into oxygen."

The ultimate fate of the tremendous volume of CO2 released into the atmosphere by burning fossil fuel is to be absorbed into the ocean, she said. There it's converted to carbolic acid.

"Right now, the uptake of CO2 by the ocean is 1 million tons of CO2 per hour," she said. This makes the oceans ever more acidic and "500 billion tons of CO2 have been taken up by the oceans since the dawn of the industrial revolution."

Many families monitor the acidity or alkalinity of their gardens or lawns, she said, showing the importance of a proper balance for a healthy ecosystem.

Too much carbolic acid will turn the oceans too acidic, McNutt added. "That is not beneficial to either the plant life or the animal life in the ocean."

The first part of the worldwide aquatic ecosystem to suffer are the coral reefs, she said. The reefs are home to many animal and plant species.

14 comments on this story

"We are already seeing signs of severe degradation in the coral reefs," she said. Some of these reefs are beginning to die. The coral is bleaching because the water is too acidic and too warm.

It's called bleaching because of the death of algae that are associated with the coral and essential to the health of the reef. "The algae photosynthesize and are in a symbiotic relationship with the corals." When they die and whiten, the coal dies.

But that's only an early step in a disaster that may be starting. Acidification could happen too swiftly for life to adapt, leaving the oceans with only a few surviving species.

"Life as we know it today has not experienced an acid ocean," McNutt said. "So they (many life forms) probably don't have the genetic wherewithal to adapt."