Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

CT scans of coral skeletons reveal ocean acidity increases reef erosion

25.11.2014

Coral reefs persist in a balance between reef construction and reef breakdown. As corals grow, they construct the complex calcium carbonate framework that provides habitat for fish and other reef organisms.

Simultaneously, bioeroders, such as parrotfish and boring marine worms, breakdown the reef structure into rubble and the sand that nourishes our beaches. For reefs to persist, rates of reef construction must exceed reef breakdown.


This is an image of µCT scan showing the outside (top) and inside (bottom) of an experimental coral block after a one-year deployment in Kāne'ohe Bay, Hawai'i. Note the bioerosion scars inside the block.

Credit: Nyssa Silbiger at UH Mānoa and Mark Riccio at the Cornell Unversity µCT Facility for Imaging and Preclinical Research

This balance is threatened by increasing atmospheric carbon dioxide, which causes ocean acidification (decreasing ocean pH). Prior research has largely focused on the negative impacts of ocean acidification on reef growth, but new research this week from scientists at the Hawai'i Institute of Marine Biology (HIMB), based at the University of Hawai'i - Mānoa (UHM), demonstrates that lower ocean pH also enhances reef breakdown: a double-whammy for coral reefs in a changing climate.

To measure bioerosion, researchers deployed small blocks of calcium carbonate (dead coral skeleton) onto the reef for one year. Traditionally, these blocks are weighed before and after deployment on the reef; however, HIMB scientists used microCT (a high-resolution CT scan) to create before and after 3-D images of each block. According to Nyssa Silbiger, lead author of the study and doctoral candidate at HIMB, this novel technique provides a more accurate measurement of accretion and erosion rates.

The researchers placed the bioerosion blocks along a 100-ft transect on shallow coral reef in Kāne'ohe Bay, Hawai'i, taking advantage of natural variability of pH in coastal reefs. The study compared the influence of pH, resource availability, temperature, distance from shore, and depth on accretion-erosion balance. Among all measured variables, pH was the strongest predictor of accretion-erosion. Reefs shifted towards higher rates of erosion in more acidic water - a condition that will become increasingly common over the next century of climate change.

This study also highlights the impact of fine-scale variation in coastal ocean chemistry on coral reefs. Current models from the International Panel on Climate Change (IPCC) predict changes in pH for the open ocean, but these predictions are problematic for coral reefs, which are embedded in highly variable coastal ecosystems. The study found dramatic differences in ocean pH and in the daily variability of pH across a short distance.

"It was surprising to discover that small-scale changes in the environment can influence ecosystem-level reef processes," said Silbiger. "We saw changes in pH on the order of meters and those small pH changes drove the patterns in reef accretion-erosion."

Silbiger and colleagues are learning all they can from the microCT scans, as this is the first time before-and-after microCT scans were used as a measure of accretion-erosion on coral reefs. In ongoing work, they are using this technology to distinguish between accretion and erosion and to single out erosion scars from specific bioeroder groups (e.g., holes from boring worms versus bioeroding sponges). The researchers are also using this technology to investigate the drivers of the accretion-erosion balance over the much larger area of the Hawaiian Archipelago.

NJ Silbiger, O Guadoyal, FIM Thomas, MJ Donahue (2014) Reefs shift from net accretion to net erosion along a natural environmental gradient. Marine Ecology Progress Series, vol. 515, doi: 10.3354/meps10999

The School of Ocean and Earth Science and Technology at the University of Hawaii at Manoa was established by the Board of Regents of the University of Hawai'i in 1988 in recognition of the need to realign and further strengthen the excellent education and research resources available within the University. SOEST brings together four academic departments, three research institutes, several federal cooperative programs, and support facilities of the highest quality in the nation to meet challenges in the ocean, earth and planetary sciences and technologies.

Marcie Grabowski | EurekAlert!
Further information:
http://www.hawaii.edu

Further reports about: CT scans HIMB Marine coral reefs microCT scans ocean acidification ocean acidity ocean pH scans skeletons

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>