These “macroalgae,” or large algal species, are big enough to essentially smother corals. They can get out of control when sewage increases nitrate levels, feeds the algae, and some of the large fish that are most effective at reducing the algal buildup are removed by fishing.
Scientists found that macroalgal competition decreased coral growth rates by about 37 percent and had other detrimental effects. Other research has documented some persistent states of hypoxia.
Researchers call this process “the slippery slope to slime.”
Findings on the research were just published in PLoS One, a professional journal. The work was supported by the National Science Foundation.
“There is evidence that coral reefs around the world are becoming more and more dominated by algae,” said Rebecca Vega-Thurber, an OSU assistant professor of microbiology. “Some reefs are literally covered up in green slime, and we wanted to determine more precisely how this can affect coral health.”
The new study found that higher levels of algae cause both a decrease in coral growth rate and an altered bacterial community. The algae can introduce some detrimental pathogens to the coral and at the same time reduce levels of helpful bacteria. The useful bacteria are needed to feed the corals in a symbiotic relationship, and also produce antibiotics that can help protect the corals from other pathogens.
One algae in particular, Sargassum, was found to vector, or introduce a microbe to corals, a direct mechanism that might allow introduction of foreign pathogens.
There are thousands of species of algae, and coral reefs have evolved with them in a relationship that often benefits the entire tropical marine ecosystem. When in balance, some algae grow on the reefs, providing food to both small and large fish that nibble at the algal growth. But the algal growth is normally limited by the availability of certain nutrients, especially nitrogen and phosphorus, and some large fish such as parrot fish help eat substantial amounts of algae and keep it under control.
All of those processes can be disrupted when algal growth is significantly increased by the nutrients and pollution from coastal waste water, and overfishing reduces algae consumption at the same time.
“This shows that some human actions, such as terrestrial pollution or overfishing, can affect everything in marine ecosystems right down to the microbes found on corals,” Vega-Thurber said. “We’ve suspected before that increased algal growth can bring new diseases to corals, and now for the first time have demonstrated in experiments these shifts in microbial communities.”
Some mitigation of the problem is already being done on high-value coral reefs by mechanically removing algae, Vega-Thurber said, but the best long-term solution is to reduce pollution and overfishing so that a natural balance can restore itself.
Corals are one of Earth’s oldest animal life forms, evolving around 500 million years ago. They host thousands of species of fish and other animals, are a major component of marine biodiversity in the tropics, and are now in decline around the world. Reefs in the Caribbean Sea have declined more than 80 percent in recent decades.
About the OSU College of Science: As one of the largest academic units at OSU, the College of Science has 14 departments and programs, 13 pre-professional programs, and provides the basic science courses essential to the education of every OSU student. Its faculty are international leaders in scientific research.
The study this story is based on is available online: http://bit.ly/QkeZkp
Rebecca Vega-Thurber | EurekAlert!
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
100 % Organic Farming in Bhutan – a Realistic Target?
15.06.2018 | Humboldt-Universität zu Berlin
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...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
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...
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.
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...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
20.06.2018 | Information Technology
20.06.2018 | Materials Sciences
20.06.2018 | Life Sciences