Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

In CO2-rich Environment, Some Ocean Dwellers Increase Shell Production

03.12.2009
In a striking finding that raises new questions about carbon dioxide’s (CO2) impact on marine life, Woods Hole Oceanographic Institution (WHOI) scientists report that some shell-building creatures—such as crabs, shrimp and lobsters—unexpectedly build more shell when exposed to ocean acidification caused by elevated levels of atmospheric carbon dioxide (CO2).

Because excess CO2 dissolves in the ocean—causing it to “acidify” —researchers have been concerned about the ability of certain organisms to maintain the strength of their shells. Carbon dioxide is known to trigger a process that reduces the abundance of carbonate ions in seawater—one of the primary materials that marine organisms use to build their calcium carbonate shells and skeletons.

The concern is that this process will trigger a weakening and decline in the shells of some species and, in the long term, upset the balance of the ocean ecosystem.

But in a study published in the Dec. 1 issue of Geology, a team led by former WHOI postdoctoral researcher Justin B. Ries found that seven of the 18 shelled species they observed actually built more shell when exposed to varying levels of increased acidification. This may be because the total amount of dissolved inorganic carbon available to them is actually increased when the ocean becomes more acidic, even though the concentration of carbonate ions is decreased.

“Most likely the organisms that responded positively were somehow able to manipulate…dissolved inorganic carbon in the fluid from which they precipitated their skeleton in a way that was beneficial to them,” said Ries, now an assistant professor in marine sciences at the University of North Carolina. “They were somehow able to manipulate CO2…to build their skeletons.”

Organisms displaying such improvement also included calcifying red and green algae, limpets and temperate urchins. Mussels showed no effect.

“We were surprised that some organisms didn’t behave in the way we expected under elevated CO2,” said Anne L. Cohen, a research specialist at WHOI and one of the study’s co-authors. “What was really interesting was that some of the creatures, the coral, the hard clam and the lobster, for example, didn’t seem to care about CO2 until it was higher than about 1,000 parts per million [ppm].” Current atmospheric CO2 levels are about 380 ppm, she said. Above this level, calcification was reduced in the coral and the hard clam, but elevated in the lobster

The “take-home message, “ says Cohen, is that “we can’t assume that elevated CO2 causes a proportionate decline in calcification of all calcifying organisms.” WHOI and the National Science Foundation funded the work.

Conversely, some organisms—such as the soft clam and the oyster—showed a clear reduction in calcification in proportion to increases in CO2. In the most extreme finding, Ries, Cohen and WHOI Associate Scientist Daniel C. McCorkle exposed creatures to CO2 levels more than seven times the current level.

This led to the dissolving of aragonite—the form of calcium carbonate produced by corals and some other marine calcifiers. Under such exposure, hard and soft clams, conchs, periwinkles, whelks and tropical urchins began to lose their shells. “If this dissolution process continued for sufficient time, then these organisms could lose their shell completely,” Ries said, “rendering them defenseless to predators.”

“Some organisms were very sensitive,” Cohen said, “some that have commercial value. But there were a couple that didn’t respond to CO2 or didn’t respond till it was sky-high—about 2,800 parts per million. We’re not expecting to see that [CO2 level] anytime soon.”

The researchers caution, however, that the findings—and acidification’s overall impact—may be more complex than it appears. For example, Cohen says that available food and nutrients such as nitrates, phosphates and iron may help dictate how some organisms respond to carbon dioxide.

“We know that nutrients can be very important,” she says. “We have found that corals for example, that have plenty of food and nutrients can be less sensitive” to CO2. “In this study, the organisms were well fed and we didn’t constrain the nutrient levels.

“I wouldn’t make any predictions based on these results. What these results indicate to us is that the organism response to elevated CO2 levels is complex and we now need to go back and study each organism in detail.”

Ries concurs that any possible ramifications are complex. For example, the crab exhibited improved shell-building capacity, and its prey, the clams, showed reduced calcification. “This may initially suggest that crabs could benefit from this shift in predator-pray dynamics. But without shells, clams may not be able to sustain their populations, and this could ultimately impact crabs in a negative way, as well,” Ries said.

In addition, Cohen adds, even though some organisms such as crabs and lobsters appear to benefit under elevated CO2 conditions, the energy they expend in shell building under these conditions “might divert from other important processes such as reproduction or tissue building.”

Since the industrial revolution, Ries noted, atmospheric carbon dioxide levels have increased from 280 to nearly 400 ppm. Climate models predict levels of 600 ppm in 100 years, and 900 ppm in 200 years.

“The oceans absorb much of the CO2 that we release to the atmosphere,” Ries says. However, he warns that this natural buffer may ultimately come at a great cost.

“It’s hard to predict the overall net effect on benthic marine ecosystems," he says. “In the short term, I would guess that the net effect will be negative. In the long term, ecosystems could re-stabilize at a new steady state.

“The bottom line is that we really need to bring down CO2 levels in the atmosphere.”

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans’ role in the changing global environment.

Media Relations | EurekAlert!
Further information:
http://www.whoi.edu

More articles from Earth Sciences:

nachricht Better model of water under extreme conditions could aid understanding of Earth's mantle
21.06.2018 | University of Chicago

nachricht The Janus head of the South Asian monsoon
21.06.2018 | Max-Planck-Institut für Chemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Better model of water under extreme conditions could aid understanding of Earth's mantle

21.06.2018 | Earth Sciences

What are the effects of coral reef marine protected areas?

21.06.2018 | Life Sciences

The Janus head of the South Asian monsoon

21.06.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>