CO2 Sea Change
Researcher studies ocean impacts on global warming
Scientists taking on the growing threat of global warming and climate change are faced with two monumental challenges: how to accurately predict the future; and, given that, how to change the future.
For nearly two decades, those fundamental goals have guided the research of Professor Mike DeGrandpre, a UM oceanographer and analytical chemist.
Landlocked Missoula, Mont., hundreds of miles from the nearest sea, might seem an unlikely place to find an oceanographer, especially one as highly respected as DeGrandpre. His research into the Earth’s marine-carbon cycle and his related technological innovations are helping scientists throughout the world understand the role of oceans in climate change caused by increasing accumulations in the atmosphere of greenhouse gases such as carbon dioxide.
Since 1990, the specific objective of DeGrandpre’s research is to determine how oceans absorb CO2 from the atmosphere.
He says that studies indicate “oceans have taken up 25 to 30 percent of CO2 pumped into the atmosphere by fossil fuel combustion and biomass burning by deforestation.
“Assuming that CO2 in the atmosphere is causing global warming,” he adds, “we pretty much know that the oceans have reduced the impact of greenhouse gases. Levels would be 25 to 30 percent higher in the atmosphere if not for the oceans.”
Through research such as his that seeks to comprehend the oceans’ mechanisms for taking up CO2, DeGrandpre says, scientists hope to more accurately predict the future, and then try to mitigate climate change.
So far, there are more questions than answers.
“With our warming climate,” he says, “how does that feed back into these processes that take up CO2? Right now we don’t know if it will have a positive or negative impact. So, as the oceans warm, will they have reduced capacity for taking up CO2 or a greater capacity? We still don’t know the answer to that.”
To find the answers, DeGrandpre invented an innovative research tool that measures the amount of dissolved CO2 in oceans or other bodies of water.
The device — called a Submersible Autonomous Moored Instrument, or SAMI-CO2 for short — is a plastic cylinder about 6 inches wide and 2 feet long. They are self-powered and capable of hourly measurements for up to one year. All data collected is logged to an internal memory chip to be downloaded later.
These sensors usually are placed a few feet underwater on permanent moorings, while others on floating drifters sample the water wherever the wind and currents carry them. The instruments have been used by researchers around the globe in a variety of studies since 1999.
DeGrandpre developed the SAMI from 1990 to 1993 during his postdoctoral work at the Woods Hole Oceanographic Institution on Cape Cod, Mass. He’s continued to make incremental improvements to the sensor since joining the UM faculty in 1996.
In addition, he created a spin-off company, Sunburst Sensors, to manufacture, market and provide technical support for SAMIs sold to other researchers. He then teamed with Missoula businessman and mechanical engineer Jim Beck, and the company’s sales and service have totaled $1.2 million from late 1999 through December of last year. The business employs one undergraduate student, two engineers and one postdoctoral research scientist.
Interest in DeGrandpre’s research using SAMI technology, he says, has generated $400,000 in grants to Sunburst from organizations such as the National Science Foundation to encourage commercial development of the system so other scientists can benefit from it.
“The science community knows I publish good, quality (research) papers,” DeGrandpre says. “That gives Sunburst credibility.”
Sunburst recently received two new grants, including $900,000 from the National Oceanographic Program, to improve the reliability of the SAMI system, which has been a problem for the company. A new model has been extensively tested in the laboratory, and a prototype will be tried at sea this year. DeGrandpre says he expects the new sensor to be in production later in 2008.
“We’ve never advertised (SAMIs) because we’ve been dealing with a non-user-friendly instrument,” he explains. “So our goal was to redesign it and market it. At that point, we could really take off. Now technical support drains the company. Also, if they don’t work, we get a bad reputation.
“We now have about 50 or 60 of these instruments out there. We can handle that level, but not more. We hope, with the new design, it will be just sort of plug-and-play. We could really sell a lot of those things.”
In addition, Sunburst has developed and started to market a new pH sensor and a novel method for measuring alkalinity, he says.
While developing the alkalinity sensor, DeGrandpre and his research group discovered a new method of titration — a standard chemical measuring technique — that immediately generated commercial interest.
The new system uses tracer chemicals, he explains, which eliminate the need to have accurate volume measurements as a prerequisite for chemical analysis.
“It’s sort of like developing a new way of slicing bread,” he says. “Sometimes you do something, and you say, ‘Why hasn’t someone done this before?’ This was surprisingly simple.”
The SAMI pH technology relates to DeGrandpre’s recently expanded research focus into ocean acidification and the possibility of increasing the ability of the oceans to take up more CO2.
“It all relates to CO2,” he says. “So the oceans are taking up all this CO2. But the CO2 forms carbonic acid like in Coca-Cola. The pH drops from that. That’s called acidification of the oceans.
“What’s that going to do to all the animals that form calcium carbonate — or shells — from the CO2 in the water? As pH drops, their ability to form shells is diminished, or impacted, because calcium carbonate solubility goes up as pH goes down.
“Here’s an example,” he adds. “Everyone around (Missoula) gets calcium carbonate buildup in their sinks, because we have relatively hard water. And we use an acid — lime — to dissolve it. Basically, we’re liming away our oceans with CO2. It has impacts on food webs and coral reefs.”
That’s a concern of scientists in the fertile ocean off the southern tip of South America, according to DeGrandpre, who was involved in an extensive research voyage on those seas from Feb. 28 to April 9 this year.
While DeGrandpre wasn’t on board the research vessel, his SAMIs are crucial to the mission, funded by the National Oceanic and Atmospheric Administration, as well as the National Science Foundation and NASA.
Sensors employed by other scientists on the research mission — studying a wide range of factors relating to CO2 exchange — were connected to DeGrandpre’s SAMI drifter system. The sensors were suspended on cables like tentacles of a jellyfish at varying depths up to 100 meters.
The drifters contain a global positioning system transmitter that allows the ship to locate them and retrieve their stored data after days of sampling the ocean.
“Our system is the main brain, collecting all the data from the sensors connected to it at various depths,” DeGrandpre says. His own studies of CO2 exchange and ocean pH are being conducted in collaboration with other scientists on board.
Theoretically, he says, the ocean’s capacity to take up CO2 could be increased by fertilization.
Our ability to change the future of climate change could be accomplished in various ways, he says, including switching to alternative energy sources and stepping up conservation efforts. Or, he suggests, it might be altered through engineering processes like sequestering carbon by fertilizing the oceans, resulting in increased plant productivity, which would allow oceans to take up more CO2 through photosynthesis.
“But what would be the effect on the food web?” he asks. “A lot of different calculations have widely different interpretations of the results of fertilizing the ocean. Right now we don’t understand the systems enough to tell if it would be a benefit or not. Some impacts are not foreseeable. That’s the reason for the research.”
— By Daryl Gadbow
The rough Labrador Sea with an inset photo of UM's Mike DeGrandpre
checking a SAMI-CO2 sensor before deployment (Photos by Dave Hebert and Mike DeGrandpre)
|A research vessel in Chile that released UM sensors near Antarctica (DeGrandpre photo)
|A SAMI-CO2 sensor is attached to this floating buoy in the Labrador Sea. (Cory Beatty photo)
|A UM sensor deployed near a coral reef in the Bahamas (Jim Hendee photo)