Bacteria in the sea are sensitive to ocean acidification caused by carbon dioxide emissions

January 12, 2016

Marine bacteria are heavily influenced by ongoing ocean acidification caused by human emissions of carbon dioxide. This discovery is made by researchers at the Institute of Marine Science (Eva Calvo, Josep Maria Gasol, Cèlia Marrasé and Carles Pelejero), together with researchers of the Linnaeus University in Sweden, the La Laguna University in Tenerife and the Institute of Environmental Assessment and Water Research (IDAEA-CSIC). The results are presented in an article in the prestigious journal Nature Climate Change. Bacteria in the sea play a crucial role in the global cycling of elements necessary to life. They act as the primary degraders of organic material produced through photosynthesis of microscopic algae in the ocean, or material released through wastewater. When algae or other organisms die, they are degraded by bacteria and, at the same time, bacteria mediate the release of elements like nitrogen or phosphorous that are essential to the food chain. Now the researchers at the ICM show that bacteria in the sea that experience ocean acidification significantly alter their metabolism. They need to invest extra energy for activating mechanisms to counterbalance the stress produced by acidification.

Bunse, C., Lundin, D., Karlsson, C.M.G., Akram, N., Vila-Costa, M., Palovaara, J., Svensson, L., Holmfeldt, K., González, J.M., Calvo, E., Pelejero, C., Marrasé, C., Dopson, M., Gasol, J.M., Pinhassi, J. (2016) Response of marine bacterioplankton pH homeostasis gene expression to elevated CO2. Nature Climate Change. http://dx.doi.org/10.1038/nclimate2914.


Mass coral bleaching now affecting half of Australia's Great Barrier Reef

April 11, 2016

Climate change and strong El Niño cause hundreds of kilometres of reef to bleach, as higher temperatures stress the coral

The mass coral bleaching event smashing the Great Barrier Reef has severely affected more than half its length and caused patches of bleaching in most areas, according to scientists conducting an extensive aerial survey of the damage.

“The good news with my last flight is that I found 50 reefs that weren’t bleached, so that may be the southern boundary,” said Terry Hughes from James Cook University. Hughes is the head of the national coral bleaching task force, which has been conducting flights over the length of the reef, mapping bleached areas and recording the severity of the damage.

Climate change and a strong El Niño have caused hundreds of kilometres of the reef to bleach, as the higher water temperatures stress the coral, and they expel their symbiotic algae. If the bleaching is bad enough, or the temperatures remain high for long enough, the corals die, putting the future of reefs at risk.

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