Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sinking islands: Does the rise of sea level endanger the Takuu Atoll in the Pacific?

02.02.2016

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister picture is being painted evoking the demise of the island states and their cultures. Are the effects of sea-level rise already noticeable on reef islands? Scientists from the ZMT have now answered this question for the Takuu Atoll, a group of Pacific islands, located northeast of Papua New Guinea.

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister picture is being painted evoking the demise of the island states and their cultures.


In the Takuu Atoll

Anke Mösinger, Leibniz Center for Tropical Marine Ecology


Ritual dances in the Takuu Atoll

Anke Mösinger, Leibniz Center for Tropical Marine Ecology

Are the effects of sea-level rise already noticeable on reef islands? Scientists from the ZMT have now answered this question for the Takuu Atoll, a group of Pacific islands, located northeast of Papua New Guinea.

Reef islands are among the landforms most vulnerable to the rise of the sea level. Researchers have already predicted that the Takuu Atoll with its ancient Polynesian culture will no longer be habitable within the next decades. The island government is said to have already made plans to relocate the community as so-called “climate refugees”. The alarming problem has also been the focus of an award-winning documentary called “There Once Was An Island” from 2010.

Not many studies, however, have as yet investigated the visible effects of climate change on reef islands. For the first time ZMT geologist Dr. Thomas Mann has now examined the changes in vegetated land area and the position of the coastline on Takuu since 1943 by closely studying areal photographs from the Second World War and an extensive set of satellite images. “The result came as quite a surprise to us,” he says.

“Although the rise of the sea level started about 100 years ago and has been progressing much faster since the 1990s, the vegetated land area of the Takuu islands has grown by a total of three percent between 1943 and 2012.”

Although a reversing trend has emerged since 2008, the loss of land however happened too suddenly to be attributed to sea-level rise. The erosion started immediately after the atoll was affected by storm waves, which eroded large parts of the islands’ coasts and contributed to the horror scenario of the sinking islands. “After such climate events islands can recover – albeit very slowly,” says Dr. Thomas Mann. “Our data have shown that the renewal of the islands already started a few years after the storm tide.”

Changing beach dimensions also added to the picture of the sinking Takuu Atoll, but the beaches only decreased in size on a number of islands – a process which was in fact man-made as the islanders removed large amounts of sand to erect artificial hills on which they traditionally built houses for the village elders. Furthermore, the islanders had constructed a massive seawall on the main island of Nukutoa to safeguard against storm tides. Instead of smoothly rolling onto the shallow shore the waves now hit the wall with huge force, whirling up and seizing the sandy beach below.

“Overall, our data do not allow any conclusion that current sea-level rise has had a negative effect on the Takuu islands in the last 70 years,” explains Dr. Mann. Coral islands are also not powerless against sea-level rise, he says. “These islands are lined with living corals, which can grow up to 20 cm per year. Entire coral reefs can still grow by around 8 mm a year, so in a manner of speaking they are faster than the current rise of the sea level.”

However, a coral reef can only keep up the pace if it is in healthy condition and not impaired by pollution, higher water temperature or destructive fishing methods. Dr. Mann says: “The health of coral reefs is a deciding factor for the future stability of reef islands.”

Publications:
Mann, T., Westphal, H. (2015) Multi-decadal shoreline changes on Takú Atoll, Papua New Guinea: Observational evidence of early reef island recovery after the impact of storm waves. Geomorphology 257. doi:10.1016/j.geomorph.2015.12.028

Mann, T., Bayliss-Smith, T., Westphal, H. (2015). A Geomorphic Interpretation of Shoreline Change Rates on Reef Islands. Journal of Coastal Research. DOI: 10.2112/JCOASTRES-D-15-00093.1

Contact:
Dr. Thomas Mann
Leibniz Center for Tropical Marine Ecology
Tel: 0421 / 23800-132
Email: thomas.mann@leibniz-zmt.de

About the Leibniz Center for Tropical Marine Ecology
In research and education the Leibniz Center for Tropical Marine Ecology (ZMT) in Bremen is dedicated to the better understanding of tropical coastal ecosystems. As an interdisciplinary Leibniz institute the ZMT conducts research on the structure and functioning of tropical coastal ecosystems and their reaction to natural changes and human interactions. It aims to provide a scientific basis for the protection and sustainable use of these ecosystems. The ZMT works in close cooperation with partners in the tropics, where it supports capacity building and the development of infrastructures in the area of sustainable coastal zone management. The ZMT is a member of the Leibniz Association.

Dr. Susanne Eickhoff | idw - Informationsdienst Wissenschaft

More articles from Earth Sciences:

nachricht How is climate change affecting fauna in the Arctic?
22.05.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Sea level as a metronome of Earth's history
19.05.2017 | Université de Genève

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

Im Focus: Hydrogen Bonds Directly Detected for the First Time

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

Media accreditation opens for historic year at European Health Forum Gastein

16.05.2017 | Event News

 
Latest News

New approach to revolutionize the production of molecular hydrogen

22.05.2017 | Materials Sciences

Scientists enlist engineered protein to battle the MERS virus

22.05.2017 | Life Sciences

Experts explain origins of topographic relief on Earth, Mars and Titan

22.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>