Featured Research

from universities, journals, and other organizations

Living Coral Reefs Provide Better Protection From Tsunami Waves

Date:
December 19, 2006
Source:
Princeton University
Summary:
Healthy coral reefs provide their adjacent coasts with substantially more protection from destructive tsunami waves than do unhealthy or dead reefs, a Princeton University study suggests. Initially spurred by the tsunami that devastated the coastlines of the Indian Ocean two years ago, the finding provides the first quantitative confirmation of a widely held theory regarding the value of living coral reefs as a defense against tsunami.

Healthy coral reefs provide their adjacent coasts with substantially more protection from destructive tsunami waves than do unhealthy or dead reefs, a Princeton University study suggests.

Initially spurred by the tsunami that devastated the coastlines of the Indian Ocean two years ago, a team of scientists developed the first-ever computer model of a tsunami strike against a reef-bounded shoreline, using a volcanic island as an example. The model demonstrates that healthy reefs offer the coast at least twice as much protection as dead reefs. The finding provides the first quantitative confirmation of a widely held theory regarding the value of living coral reefs as a defense against tsunami waves, which are often generated by powerful undersea earthquakes.

Princeton professor Michael Oppenheimer said his team's work will give scientists the ability to quantify how much any given reef will benefit its particular stretch of coast.

"Healthy reefs have rougher surfaces, which provide friction that slows the waves substantially in comparison with smoother, unhealthy ones," said Oppenheimer, the Albert G. Milbank Professor of Geosciences and International Affairs. "Scientists had never before studied this effect by the numbers, nor had they ever analyzed it over a wide variety of coastal shapes. This study provides yet another motivating factor for protecting the planet's coral reefs from degradation."

The team's findings appear in the Dec. 14 edition of the journal, Geophysical Review Letters. In addition to Oppenheimer, other team members include Robert Hallberg, who is head of the Oceans and Climate Group at the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Lab, and Catherine Kunkel, who is the paper's lead author. Kunkel spearheaded the work during her senior undergraduate year at Princeton, from which she graduated with a physics degree in June.

Though anecdotal observations of reefs' effects on tsunami abounded after the 2004 Indian Ocean strike, Kunkel said, it was difficult to form any real conclusions because so many of these observations came after the fact. The goal of this study, which began as Kunkel's senior thesis project, was to provide a systematic framework by which to examine the assumption that healthy reefs protect shorelines more effectively.

"For our purposes, we assumed that the health of the reef would only be important in terms of the drag it exerted on the wave," said Kunkel, who is currently working as a research assistant at Tsinghua University in China. "If you have a healthy reef, it has lots of live coral branching out, sticking a lot of small obstacles into the water. A dead reef, on the other hand, is not as rough -- it tends to erode and exerts less drag on the wave."

A turbulent mountain of water crashing over a complicated rough surface presented Kunkel with a number of obstacles for her own study -- specifically, how to find a way to express each of these effects with a mathematical formula that a computer could employ to simulate it. Different complex parameters had to be considered one by one: the width and depth of the reef; the roughness of its surface; the size of the lagoon behind it; and the slope of the coast beyond. And the overarching element was the wave itself and its interaction with all these obstacles. Eventually, Kunkel found a set of equations that provided a limited but comprehensive picture of a tsunami strike.

"We had to idealize a number of factors, because we wanted to create a model that could be used for a general shoreline," Kunkel said. "For example, we had to consider a perfectly even ocean floor, because uneven ones can funnel a wave into a certain area."

Despite the limitations of the model, Oppenheimer said it provides a sound basis for the team's conclusions.

"The general conclusion is that a healthy reef might provide twice as much protection as a dead one," he said. "This could translate into sparing large sections of inshore area from destruction."

Because coral reefs are dying from rising ocean temperatures, increasing ocean acidity, and direct human damage, Oppenheimer said the findings offer yet another reason to protect these fragile offshore ecosystems.

"This study shows yet another way that protecting the environment relates to humanity in a very tangible way," he said. "Villages get built behind coral reefs for good reasons, and this is one of them."

Kunkel said that she hoped the study would inspire other scientists to continue the research by obtaining more observational data. Incorporating such data into the team's theoretical model, she said, would then allow scientists to plan better for future tsunami strikes along local coastlines.

"We now have a basic idea of what variables are important, but if you want to quantify the effectiveness of a barrier reef around a particular island, you'd want to model that island directly," Kunkel said.


Story Source:

The above story is based on materials provided by Princeton University. Note: Materials may be edited for content and length.


Cite This Page:

Princeton University. "Living Coral Reefs Provide Better Protection From Tsunami Waves." ScienceDaily. ScienceDaily, 19 December 2006. <www.sciencedaily.com/releases/2006/12/061218122605.htm>.
Princeton University. (2006, December 19). Living Coral Reefs Provide Better Protection From Tsunami Waves. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2006/12/061218122605.htm
Princeton University. "Living Coral Reefs Provide Better Protection From Tsunami Waves." ScienceDaily. www.sciencedaily.com/releases/2006/12/061218122605.htm (accessed April 23, 2014).

Share This



More Earth & Climate News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

UN Joint Mission Starts Removing Landmines in Cyprus

UN Joint Mission Starts Removing Landmines in Cyprus

AFP (Apr. 23, 2014) — The UN mission in Cyprus (UNFICYP) led a mine clearance demonstration on Wednesday in the UN-controlled buffer zone where demining operations are being conducted near the Cypriot village of Mammari. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
California Drought Is Good News for Gold Prospectors

California Drought Is Good News for Gold Prospectors

AFP (Apr. 22, 2014) — For months California has suffered from a historic drought. The lack of water is worrying for farmers and ranchers, but for gold diggers it’s a stroke of good fortune. With water levels low, normally inaccessible areas are exposed. Duration: 01:57 Video provided by AFP
Powered by NewsLook.com
Raw: MN Lakes Still Frozen Before Fishing Opener

Raw: MN Lakes Still Frozen Before Fishing Opener

AP (Apr. 22, 2014) — With only three weeks until Minnesota's fishing opener, many are wondering if the ice will be gone. Some of the Northland lakes are still covered by up to three feet of ice, causing concern that just like last year, the lakes won't be ready. (April 22) Video provided by AP
Powered by NewsLook.com
Scientists Warn Of Likely El Niño Event This Year

Scientists Warn Of Likely El Niño Event This Year

Newsy (Apr. 22, 2014) — With Pacific ocean water already showing signs of warming, the NOAA says there's about a 66 percent chance the event will begin before November. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins