Natural carbon dioxide (CO2) seeps in Papua New Guinea have given scientists rare insights into what tropical coral reefs could look like if human-induced atmospheric CO2 concentrations continue to rise unabated. At present rates of increase, the Intergovernmental Panel on Climate Change (IPCC) forecasts atmospheric CO2 levels of about 750ppm or more by 2100. About a third of this extra atmospheric CO2 is absorbed by the world’s oceans. As a consequence, pH levels will drop from 8.1 to 7.8, resulting in increased ocean acidification which will severely impact marine ecosystems.
Site exposed to very high concentrations of CO2 concentrations where coral developement ceases to exist. Katharina Fabricius, AIMS
Seascape at control site
Katharina Fabricius, AIMS
The coral reefs, having the highest biodiversity of all marine ecosystems, are probably the most vulnerable.
Dr Katharina Fabricius, scientist at the Australian Institute of Marine Science (AIMS) has led two research expeditions, with researchers from six countries including Germany, USA and Papua New Guinea. Among the international team of scientists was a group from the Max Planck Institute for Marine Microbiology in Bremen, experts in the field of microsensors, a valuable tool for studying coral reefs.
The team of scientists studied three natural CO2 seeps in Milne Bay Province, Papua New Guinea. This unique location was discovered by chance during a field trip to document biodiversity and is the only presently known cool CO2 seep site in tropical waters containing coral reef ecosystems. The study has given scientists unprecedented insights into what coral reefs would look like if greenhouse gas emissions and resulting ocean acidification continues to increase at present rates. At the seeps, streams of CO2 bubbles emanate from the ocean floor due to volcanic activity.
This week a scientific paper on the first results of this study is published in the prestigious, international scientific journal Nature Climate Change. It is the first scientific paper to present data on tropical coral reef ecosystems that are naturally adapted and acclimatised to elevated CO2. “Our research showed us there will be some winners, but many more losers, when tropical coral reefs are exposed to ocean acidification,” said principal investigator Dr. Fabricius. “In the past, we have relied on short-term laboratory experiments to tell us what happens to marine organisms exposed to ocean acidification,” she said. “Those experiments indicated deleterious effects on the performance of many species.”
While laboratory experiments are important, Dr Fabricius said the natural CO2 seeps in Milne Bay provided a more complete picture about the ecological consequences for coral reef communities when exposed to higher levels of CO2 for many decades. This natural setting allowed scientists to compare coral reef communities along a gradient from normal present day to low pH.
“The cover of the more delicate tabulate, foliose and branching corals was reduced three-fold near the CO2 seeps. Similarly, the abundance of soft corals and sponges were also significantly reduced. Most importantly we found that reef development ceased below pH level 7.7.”
One of the MPI co-authors, Martin Glas said: “Not only did coral abundance change, also other calcifiers like foraminifera and calcifying algae were strongly reduced under elevated CO2 levels. This is disturbing news as they represent key-species for the formation of a healthy coral reef and contribute significantly to the reefs calcium carbonate production.”
Amongst the few winners at higher levels of CO2 were seagrasses which showed increased cover with three to four times more shoots and roots than under normal conditions.Dr Fabricius said the study showed that ocean acidification leads to profound changes in coral reefs ecosystems. “The decline of the structurally complex corals means the reef will be much simpler and there will be less habitat for the hundreds of thousands of species we associate with today’s coral reefs.
“They would not be the richly diverse and beautiful habitats we currently see in places such as the Great Barrier Reef.”
“There are also fewer juvenile corals in areas with high CO2 levels, therefore coral reefs in those environments face greater challenges recovering from disturbances such as tropical storms.
“Ultimately, what we observed was that the diversity of reefs progressively declines with increasing CO2. At concentrations similar to those predicted for the end of this century at a ‘business as usual’ emissions scenario, the “coral reef” observed was depauperate and lacked the structural complexity of present healthy tropical coral reefs. These changes are simply due to ocean acidification, i.e., even without the projected +2°C warming of the oceans associated with rising greenhouse gases. The 0.5°C warming we have already observed in the tropics in the last 50 years has already caused mass coral bleaching events and declining coral calcification.”
Dr Fabricius said: “The rate of increase of atmospheric CO2 continues to accelerate due to human activities. The range of exposures at the Milne Bay seep sites are comparable to end-of-century CO2 projections.“It would be catastrophic if pH levels dropped below 7.8."
Dr Fabricius said it was important for the researchers to continue their study in the unique location in Papua New Guinea and future expeditions are in preparation.For further information contact:
Dr. Manfred Schloesser | Max-Planck-Institut
Further reports about: > CO2 > CO2 concentration > CO2 levels > Climate change > Fabricius > Marine Microbiology > Marine science > Max Planck Institute > Pacific Ocean > atmospheric CO2 > coral reef > coral reef ecosystems > gas emission > greenhouse gas > greenhouse gas emission > marine ecosystem > microbiology > ocean acidification > pH level > reef ecosystem > tropical storm
Modeling magma to find copper
13.01.2017 | Université de Genève
What makes erionite carcinogenic?
13.01.2017 | Friedrich-Schiller-Universität Jena
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Power and Electrical Engineering
16.01.2017 | Information Technology
16.01.2017 | Power and Electrical Engineering