Nav: Home

Stony corals: Limits of adaption

August 08, 2019

Corals fascinate amateurs and experts alike: small polyps that extract calcium carbonate from seawater and use it to build their elaborate skeletons. But climate change, with rising water temperatures and increasing ocean acidification, is changing the living conditions of corals at an unprecedented rate. Whether they can keep pace with these changes and adapt is an open question. Now researchers from the GEOMAR Helmholtz Centre for Ocean Research Kiel and the University of California are providing new insights with a study published today in international journal Nature Communications. For this study, which was co-financed by the Austrian Science Fund FWF (Fonds zur Förderung der wissenschaftlichen Forschung) and the US NSF, the scientists investigated the response of the stony corals Porites astreoides to low pH and high dissolved carbon content in their natural environment.

Over millions of years of their evolution, corals have experienced and survived major environmental changes. Like tree rings, their skeletons are an environmental archive that allows researchers to gain insights into the past. From the smallest differences in the chemical composition of coral skeletons, conclusions can be drawn about former environmental conditions. However, many details on the control and regulation of skeletal formation processes of corals are still unknown.

To learn more about these processes, the researchers used a natural laboratory off the east coast of Mexico. There, groundwater seeps from almost circular holes in the seabed, so-called ojos. The water has previously dissolved calcium carbonate from the Yucatan peninsula rocks as well as high carbon dioxide from soil respiration. It is more acidic than normal seawater but contains more dissolved carbon and thus resembles the seawater of the distant future.

Despite these unfavorable conditions, the hard-coral Porites astreoides has settled at these ojos. However, the corals there grow more slowly than similar species outside the ojos. "Unlike corals that are exposed to such an acidic environment in laboratory experiments for only a few weeks to months, the corals we sampled live under such conditions for their whole life history," says Prof. Dr. Adina Paytan of the University of California Santa Cruz, co-author of the study..

For the study, samples were taken from corals living at different distances from the ojos. The researchers were thus able to study corals of the same species with varying degrees of change in seawater composition.

It is known from earlier research that the ratio of boron and carbon isotopes in coral skeletons provides information on the chemical properties of the calcifying fluid at the time of skeleton formation. "Kiel is one of the few locations where we have the necessary analytics to be able to measure these parameters simultaneously and with high resolution", explains Dr. Jan Fietzke, physicist at GEOMAR and co-author of the study, "We are thus able to measure two important parameters of coral calcification".

The investigations showed an almost constant chemical composition of all samples. "From this, we can conclude that each polyp creates a calcifying fluid that is largely independent of the seawater conditions surrounding it," explains GEOMAR marine biologist Dr. Marlene Wall, first author of the study, "yet even small changes in the two parameters studied can have an effect on calcification." Model calculations for coral growth based on these chemical data resembled the decline in growth measured in the field highlighting their importance to facilitate growth. In an environment with a lower pH, the corals at the ojos must put more effort to raise their pH to the observed level. This process is likely to cost them more energy.

Since the corals must distribute their energy reserves over many important functions such as food acquisition, digestion, reproduction or defense against diseases, they grow more slowly. Other influences, however, such as the calcium concentration in the calcifying fluid or the role of coral symbionts, offer potential for further research. "The study has also shown that we still have a long way to go before we understand all the interactions between changes in seawater and coral growth," summarizes Dr. Wall.
-end-


Helmholtz Centre for Ocean Research Kiel (GEOMAR)

Related Science Articles:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.
Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.
Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.
Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.
World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.
PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.
Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.
Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.
More Science News and Science Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.