Broadcast study of ocean acidification to date helps scientists evaluate effects on marine life

Jan 23, 2012
The image shows a SeaFET pH sensor deployed underneath approximately 12 feet of sea ice in McMurdo Sound, Ross Island, Antarctica, in Oct. 2010. Scientists use these sensors to identify the natural dynamics of ocean pH in order to better understand how marine organisms may be impacted by climate change. The black object is the sensor, which is anchored to the ocean bottom using weights. Along the ocean bottom, worms and sea stars are visible. Credit: Rob Robbins

Might a penguin's next meal be affected by the exhaust from your tailpipe? The answer may be yes, when you add your exhaust fumes to the total amount of carbon dioxide lofted into the atmosphere by humans since the industrial revolution. One-third of that carbon dioxide is absorbed by the world's oceans, making them more acidic and affecting marine life.

A UC Santa Barbara marine scientist and a team of 18 other researchers have reported results of the broadest worldwide study of ocean acidification to date. Acidification is known to be a direct result of the increasing amount of greenhouse gas emissions. The scientists used sensors developed at Scripps Institution of Oceanography at UC San Diego to measure the acidity of 15 ocean locations, including seawater in the Antarctic, and in temperate and .

As oceans become more acidic, with a lower pH, are stressed and entire ecosystems are affected, according to the scientists. Gretchen E. Hofmann, an eco-physiologist and professor in UCSB's Department of Ecology, Evolution & Marine Biology, is lead author of the recent article in PLoS ONE that describes the research.

"We were able to illustrate how parts of the world's oceans currently have different pH, and thus how they might respond to climate changes in the future," said Hofmann. "The sensors allowed us to capture that." The sensors recorded at least 30 days of continuous pH values in each area of the study.

Since the beginning of the industrial revolution, human activities have accelerated the release of carbon dioxide into the atmosphere as mixes with water. The two molecules combine to become carbonic acid, making seawater more acidic. As billions of molecules combine and go through this process, the overall pH of the oceans decreases, causing ocean acidification.

Acidification limits the amount of carbonate forms that are needed by marine invertebrates, such as coral, urchins, snails, and shellfish, to make their skeletons. As the concentration of carbonates decreases in acidified water, it is harder to make a shell. And, the structures of some organisms may dissolve when water chemistry becomes too unfavorable.

"The emerging pH data from sensors allows us to design lab experiments that have a present-day environmental context," said Hofmann. "The experiments will allow us to see how organisms are adapted now, and how they might respond to climate change in the future."

Hofmann researched the Antarctic, where she has worked extensively, as well as an area of coral reefs around the South Pacific island of Moorea, where UCSB has a Long-Term Ecological Research (LTER) project. She also studied the coastal waters of Santa Barbara, in conjunction with UCSB's Santa Barbara Coastal LTER. The research team provided 30 days of pH data from other ocean areas around the world.

UCSB graduate student Emily Rivest positions a SeaFET pH sensor in a coral reef off the island of Moorea, in French Polynesia. The large cement posts once held up a pier that toppled over the reef; one of the fallen posts provides an anchor for the sensor. The grey bottle is used to collect seawater samples for chemical analyses that augment the pH data. The reefs surrounding the island of Moorea are home to UCSB's Coral Reef Long-Term Ecological Research site (MCR LTER). Credit: Anderson Mayfield

The researchers found that, in some places such as Antarctica and the Line Islands of the South Pacific, the range of pH variance is much more limited than in areas of the California coast that are subject to large vertical movements of water, known as upwellings. In some of the study areas, the researchers found that the decrease in seawater pH being caused by is still within the bounds of natural pH fluctuation. Other areas already experience daily acidity levels that scientists had expected would only be reached at the end of this century.

"This study is important for identifying the complexity of the ocean acidification problem around the globe," said co-author Jennifer Smith, a marine biologist with Scripps. "Our data show such huge variability in pH, both within and across marine ecosystems, making global predictions of the impacts of ocean acidification a big challenge."

Todd Martz, a marine chemistry researcher at Scripps, developed the sensor. "When I arrived at Scripps, we re-engineered my prototype design, and since then I have not been able to keep up with all of the requests for sensors," said Martz. "Because every sensor used in this study was built at Scripps, I was in a unique position to assimilate a number of datasets, collected independently by researchers who otherwise would not have been in communication with each other. Each time someone deployed a sensor, they would send me the data, and eventually it became clear that a synthesis should be done to cross-compare this diverse collection of measurements." Hoffman worked with Martz to put together the research team to create that synthesis.

The team noted that the Scripps sensors, called "SeaFET" and "SeapHOx," allow researchers to continuously and autonomously monitor pH from remote parts of the world, providing important baselines from which scientists can monitor future changes caused by .

Despite surveying 15 different ocean regions, the authors noted that they only made observations on coastal surface oceans, and that more study is needed in deeper ocean regions farther away from land.

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User comments : 24

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Meyer
1.4 / 5 (9) Jan 23, 2012
The oceans are not acidic, so it is impossible for them to become "more acidic."
SoylentGrin
4 / 5 (8) Jan 23, 2012
Anything can become more acidic. If something goes from pH 9 to pH 8, even though it's still on the base side of the scale, it has become more acidic. It has also become less basic.
But it's better to say that absorbing CO2 makes the oceans more acidic, rather than saying it makes them less basic, because then you aren't mixing the concepts of adding something (CO2) resulting in something being less (basic).

Did you really want to play semantics rather than address the content of the article?
Brian_Brown
1.6 / 5 (7) Jan 23, 2012
Ocean vents (90% of Earth's volcanoes) couldn't have anything to do with this could they?

Parsec
5 / 5 (6) Jan 23, 2012
Ocean vents (90% of Earth's volcanoes) couldn't have anything to do with this could they?


Where did you extract the number "90% of earth's volcano's?.

And sure they could. But follow the logic. It not hard. Shells made out of calcium carbonate dissolve in even slightly acidic water. Ergo, we can rather easily see the history of how acidic the oceans have been in the past by looking at these shells.

Unless your suggesting that somehow the number of oceanic vents are increasing in the last few hundred years, its extremely unlikely that they could be the cause of an increase in ocean acidity. Whereas even a simple back-of-the envelope calculation of how much CO2 has been absorbed by human civilization in the last 200 years gives pretty good agreement with the increase in acidity.
Meyer
1.6 / 5 (7) Jan 23, 2012
Anything can become more acidic. If something goes from pH 9 to pH 8, even though it's still on the base side of the scale, it has become more acidic. It has also become less basic.
But it's better to say that absorbing CO2 makes the oceans more acidic, rather than saying it makes them less basic, because then you aren't mixing the concepts of adding something (CO2) resulting in something being less (basic).

Did you really want to play semantics rather than address the content of the article?

So if the ocean temperature falls from 50 to 49 degrees, it has become more icy? And it's not a semantic game. It's a semantic error in the article. An alternative would be to say "as the oceans' acidity increases ..."
SoylentGrin
4 / 5 (4) Jan 23, 2012
So if the ocean temperature falls from 50 to 49 degrees, it has become more icy?


The temperature has become colder, yes, just as if pH falls, it has become more acidic.
Don_Norris
3 / 5 (2) Jan 23, 2012
"Ocean acidification refers to the process of lowering the oceans pH (that is, increasing the concentration of hydrogen ions) by dissolving additional carbon dioxide in seawater from the atmosphere. The word acidification refers to lowering pH from any starting point to any end point on the pH scale. This term is used in many other scientific areas (including medicine and food science) to refer to the addition of an acid to a solution, regardless of the solution's pH value. For example, even though seawater's pH is greater than 7.0 (and therefore considered basic in terms of the pH scale), increasing atmospheric CO2 levels are still raising the ocean's acidity and lowering its pH. In comparison, this language is similar to the words we use when we talk about temperature. If the air temperature moves from -40°C to -29°C (-40°F to -20°F), it is still cold, but we call it warming. James Orr, Senior Scientist, Laboratory for the Sciences of Climate and Environment, France; Christo
Meyer
1.6 / 5 (7) Jan 23, 2012
"it is still cold, but we call it warming"

Poor analogy. You wouldn't say it has become "hotter" or "more hot" because that assumes "hot" as the starting point. You could accurately say the oceans are acidifying but not that they are becoming "more acidic." Moreover, while "hot" is subjective, "acidic" has a precise definition and the oceans are objectively not acidic.
SoylentGrin
3 / 5 (2) Jan 23, 2012
He was quoting James Orr, the senior scientist at the Laboratory for the Sciences of Climate and Environment. I'm sure you can school him on his use of terminology.
Meyer
1.8 / 5 (5) Jan 23, 2012
He was quoting James Orr, the senior scientist at the Laboratory for the Sciences of Climate and Environment. I'm sure you can school him on his use of terminology.


Why? James Orr wasn't misusing terminology or misapplying his example. I think he would agree with my nit picking. Lazy writing leads to unnecessary confusion.
MarkyMark
1 / 5 (2) Jan 24, 2012
He was quoting James Orr, the senior scientist at the Laboratory for the Sciences of Climate and Environment. I'm sure you can school him on his use of terminology.


Why? James Orr wasn't misusing terminology or misapplying his example. I think he would agree with my nit picking. Lazy writing leads to unnecessary confusion.

Pot calling the Kettle black........!
rubberman
5 / 5 (1) Jan 24, 2012
"it is still cold, but we call it warming"

Poor analogy. You wouldn't say it has become "hotter" or "more hot" because that assumes "hot" as the starting point. You could accurately say the oceans are acidifying but not that they are becoming "more acidic." Moreover, while "hot" is subjective, "acidic" has a precise definition and the oceans are objectively not acidic.

Since we're nit picking grammar, lose the word "more" from in front of acidic and you're statement is correct. But, if something is acidifying, it is becoming more acidic my friend. Just as water that is in a state of continuous cooling is in the process of solidifying or becoming more solid, but until it is actually ice you cannot say it is solid.
Deathclock
not rated yet Jan 24, 2012
The oceans are not acidic, so it is impossible for them to become "more acidic."


Wow... basic science fail.
Deathclock
not rated yet Jan 24, 2012
Meyer, you are wrong.

The pH scale is a SCALE. If something moves toward one end of the scale, regardless of where it is on that scale, it is becoming more of that. If we define one side of the scale to be acidic, and one side to be basic, and we measure something that is all the way to the basic side of the scale, and it moves one unit to the other side, it is correct to say that it became more acidic.

Just like if we measure the temperature at -100 degrees and then later -99 degrees it is correct to say it became warmer.
Meyer
3 / 5 (2) Jan 25, 2012
So, -99 is more positive than -100? No, neither one is positive at all.
rubberman
not rated yet Jan 25, 2012
So, -99 is more positive than -100? No, neither one is positive at all.


Again nit picking basic grammar, the above should read:
So -99 is more positive than -100, ALTHOUGH neither one is positive at all...
The only 2 ways in describing the # -99 as it relates to -100 are either more positive or less negative...take your pick.
Deathclock
5 / 5 (1) Jan 25, 2012
So, -99 is more positive than -100? No, neither one is positive at all.


-99 is LARGER than -100, even though neither are large, yes. It can also accurately be described as being closer to positive. The difference here is that there is an absolute point on the scale that serves as a demarcation between positive and negative, no such point exists on most other scales. There is no set point where something is acidic or is not acidic, the scale measures acidity, all points along it are described by the level of acidity.
rubberman
not rated yet Jan 25, 2012
LMAO...it is also larger...3 ways..sorry. I guess a 4th would be not smaller.....
Meyer
3.7 / 5 (3) Jan 25, 2012
The only 2 ways in describing the # -99 as it relates to -100 are either more positive or less negative...take your pick.

Less negative, obviously. And there are obviously more than two options: greater, closer to 0, increasing, etc.

-99 is LARGER than -100, even though neither are large, yes. It can also accurately be described as being closer to positive.

All true, but it is not MORE past some threshold that it has not passed.

There is no set point where something is acidic or is not acidic

Yes, there is. Just as a number below 0 is negative, a substance with acidity below a pH of 7 is acidic. 1 is not "more negative" than 2, just as 8 is not "more acidic" than 9.
Meyer
3.7 / 5 (3) Jan 25, 2012
I was just offering a minor correction. It is surprising how many people want to defend such a basic mistake. If it gets any more basic, it might become basic.
Deathclock
5 / 5 (1) Jan 25, 2012
If the temperature goes from -50 to -49 it has become warmer (more warm and less cold), it has also become hotter (more hot and less cold). Likewise, if the pH of a solution goes from 10 to 9 it has become more acidic and less basic, BOTH are true.
bewertow
1 / 5 (1) Jan 28, 2012
So, -99 is more positive than -100? No, neither one is positive at all.


The integers are an ordered field, so clearly you can say which one is greater. Learn to do basic math, n00b.
Meyer
3.7 / 5 (3) Jan 28, 2012
I said "more positive," not "greater." Would you say 1.3 is "more of an integer" than 1.4?
RitchieGuy
3 / 5 (2) Feb 04, 2012
The proper term for 1 degree lower than basic would be "BECOMING acidic", while 2 degrees lower and more would then be "MORE acidic" because the 1 degree lower is the starting base or point from the basic ph. With every degree lower from basic, you could then say, "it's becoming more acidic". And, subsequently, more and more acidic. But the first initial point below basic ph should only be "becoming acidic" since it was not acidic before that.

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