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 Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University

nachricht NASA finds strongest storms in weakening Tropical Cyclone Sanba
15.02.2018 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>