Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Submarine springs can cause problems for coral reefs

27.09.2019

Climate change, ocean acidification, overfishing – coral reefs are exposed to many damaging influences. A team of scientists from the Leibniz Centre for Tropical Marine Research (ZMT) has now come across another threat that could have far more impact than previously thought: submarine groundwater discharge. They have detailed their findings in the journal Limnology and Oceanography.

Many divers are familiar with the phenomenon: when diving through a coral reef, the water can suddenly become blurred and much colder, which is often the result of groundwater seeping through the seabed after having made its way from the land over many kilometres through rock and sand layers.


Groundwater leak from a crater in a reef off Lombok

Photo: Till Oehler, Leibniz Centre for Tropical Marine Research


Groundwater source in a reef off Lombok

Photo: Imke Podbielski, Leibniz Centre for Tropical Marine Research

Submarine groundwater springs are widespread all over the world, but have hardly been studied by scientists to date. According to previous estimates, such springs account for up to 10% of the water discharged from land into the sea.

They are particularly common in volcanic regions, where the groundwater can flow easily along fissures and cracks through the underground.

Together with partners from the Indonesian Research Centre of Geotechnolgy, Till Oehler, geologist at ZMT, discovered a large number of submarine springs in a coral reef off Lombok, a volcanic island in Indonesia.

On closer inspection they found deep cracks and crevices in the reef alongside the springs; in some cases large craters with a diameter of up to 16 metres had formed. Coral debris accumulated on the seabed, and algae had started to overgrow the reef.

Measurements by the researchers showed that a large amount of water is discharged from the individual springs in the reef: up to five litres per second. “This type of groundwater is usually heavily polluted and very rich in nutrients such as nitrate or phosphate, as it carries fertiliser and wastewater from industry, agriculture and settlements. Lombok and many other islands in the region have virtually no sewage treatment plants,” reports Dr. Till Oehler.

To investigate water chemistry, the geologists took groundwater samples from the reef and from wells on land. They found that the nitrate levels at the reef springs were 40 times higher than in the surrounding water. They were also able to trace the origin of the reef springs, which was located on Lombok in a densely populated valley region.

Coral reefs thrive best in nutrient-poor, clear water. An excess of nutrients can lead to strong algae growth. Algae then compete with corals for the settlement in the reef, resulting in overgrowth and eventual death of the corals. “In addition, the submarine groundwater springs produce water which is more acidic than seawater and can impair skeleton formation and thus coral growth.”, explains Professor Nils Moosdorf, who leads the working group “Submarine Groundwater Discharge” at ZMT.

Freshwater springs, as described by the researchers, were also found in reefs off Hawaii, Mexico and the Philippines. The ZMT scientists assume that they are widespread. Along the Pacific, for example, where continental plates collide at the Pacific Ring of Fire, islands of volcanic origin line up in front of Australia and Southeast Asia, like pearls on a chain. The area is rich in coral reefs and one of the most biodiverse marine regions on Earth and the researchers also suspect further groundwater springs there.

“Groundwater is fed by rain which is especially high during the monsoon season,” says Professor Moosdorf. “According to forecasts on the consequences of climate change, rainfall in the region is expected to become even more intense. This could lead to a further increase in submarine groundwater discharge and its nutrient load.”

Wissenschaftliche Ansprechpartner:

Dr. Till Oehler
Leibniz Centre for Tropical Marine Research (ZMT)
Tel: 0421 - 23800 135
E-mail: till.oehler@leibniz-zmt.de

Prof. Dr. Nils Moosdorf
Leibniz Centre for Tropical Marine Research (ZMT)
Tel: Tel: 0421 - 23800 33
E-mail: nils.moosdorf@leibniz-zmt.de

Originalpublikation:

Oehler, T., Bakti, H., Lubis, R. F., Purwoarminta, A., Delinom, R., & Moosdorf, N. (2019). Nutrient dynamics in submarine groundwater discharge through a coral reef (western Lombok, Indonesia). Limnology and Oceanography, lno.11240. https://doi.org/10.1002/lno.11240

Dr. Susanne Eickhoff | idw - Informationsdienst Wissenschaft

Further reports about: Tropenforschung ZMT coral reef coral reefs corals groundwater springs nitrate volcanic

More articles from Earth Sciences:

nachricht The Antarctica Factor: model uncertainties reveal upcoming sea-level risk
14.02.2020 | Potsdam-Institut für Klimafolgenforschung

nachricht How the ocean is gnawing away at glaciers
04.02.2020 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

Im Focus: Skyrmions like it hot: Spin structures are controllable even at high temperatures

Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices

The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...

Im Focus: Making the internet more energy efficient through systemic optimization

Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.

Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.

Im Focus: New synthesis methods enhance 3D chemical space for drug discovery

After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.

"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.

Im Focus: Quantum fluctuations sustain the record superconductor

Superconductivity approaching room temperature may be possible in hydrogen-rich compounds at much lower pressures than previously expected

Reaching room-temperature superconductivity is one of the biggest dreams in physics. Its discovery would bring a technological revolution by providing...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

Empowering the cell’s disposal system to deal with disease-prone garbage

17.02.2020 | Life Sciences

Freiburg researcher investigate the origins of surface texture

17.02.2020 | Materials Sciences

How do rotor blades deform in wind gusts?

17.02.2020 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>