The naturally low pH (a measure of acidity) in the water around the springs creates conditions similar to those that will result from the widespread acidification of surface waters that scientists expect to occur as the oceans absorb increasing amounts of carbon dioxide from the atmosphere.
Ecological surveys around the springs found small, patchily distributed colonies of only a few species of corals, without the structurally complex corals that compose the framework of the nearby Mesoamerican Barrier Reef, one of the Caribbean's largest coral reef ecosystems.
A team led by scientists at the University of California, Santa Cruz, has been studying the submarine springs at Puerto Morelos near the Mesoamerican reef for the past three years. The researchers reported their findings in a paper published in the journal Coral Reefs (published online Nov. 20).
"This study has some good news and some bad news for corals," said coauthor Adina Paytan, a research professor in the Institute of Marine Sciences at UC Santa Cruz. "The good news is that some species of corals are able to calcify and grow at very low pH. The bad news is that these are not the ones that build the framework of the coral reefs. So if this is an indication of what will happen with future ocean acidification, the reefs will not be as we know them today."
The submarine springs, known as "ojos," occur along the eastern coast of the Yucatan Peninsula. Limestone "karst" landforms near the coast feature underground drainage systems that discharge brackish water at the ojos. The discharged water has lower pH than the surrounding seawater, and these conditions have existed for thousands of years. Lowering the pH affects the chemical equilibrium of seawater with respect to calcium carbonate, reducing the concentration of carbonate ions and making it harder for organisms such as corals to build and maintain structures of calcium carbonate.
Paytan's team monitored the pH and other conditions at ten ojos and conducted ecological surveys around each site. The researchers found that the number of coral species and the size of coral colonies declined with increasing proximity to the center of an ojo. Only a few species of hard corals were found in waters with the lowest carbonate saturation levels, closest to the ojos. These species are rarely major contributors to the framework of Caribbean reefs, but their ability to form carbonate skeletons in low-pH conditions warrants further study, Paytan said.
"We need to understand the mechanisms that allow these corals to calcify at these low-pH conditions. We should also make sure that the places where these species occur are protected," she said.
The low pH and low carbonate saturation near the ojos are comparable to the conditions scientists expect to see worldwide due to ocean acidification by the year 2100. Other conditions at the ojos are different, however, including somewhat lower salinity and high nutrient concentrations in the discharge water. Evidence from previous studies suggests that the low salinity is not responsible for the patterns seen around the ojos, since coral species that tolerate similarly low salinity occur in the region but were not found near the ojos. The high nutrient concentrations may benefit the corals, helping them compensate for the increased energy needed for calcification under low-pH conditions.
Elizabeth Crook, a graduate student in Earth and planetary sciences at UC Santa Cruz, is first author of the Coral Reefs paper. In addition to Crook and Paytan, the coauthors include Donald Potts, professor of ecology and evolutionary biology at UCSC, and Mario Rebolledo-Vieyra and Laura Hernández at the Centro de Investigación Científica de Yucatán. This research was funded by the National Science Foundation.
Tim Stephens | EurekAlert!
Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences