Study finds Great Barrier Reef is an effective wave absorber

University of Southampton News Release: New research has found that the Great Barrier Reef, as a whole, is a remarkably effective wave absorber, despite large gaps between the reefs. This means that landward of the reefs, waves are mostly related to local winds rather than offshore wave conditions.

As waves break and reduce in height over reefs, this drives currents that are very important for the transport of nutrients and larvae. This reduction in wave height also has implications for shoreline stability. Transition

The Great Barrier Reef in Australia is the largest coral reef system in the world, extending 2,300 km alongshore. The reef matrix is a porous structure consisting of thousands of individual reefs, with gaps in between. The porosity varies in that is it much lower in the north where the continental shelf is narrow and there is extensive reef flats; and is greater in the south where the shelf reaches up to 300 km wide and there are extensive lagoons.

Previously, there have been several studies investigating how individual reefs in the Great Barrier Reef influence ocean waves. However, this was the first, comprehensive, large-scale study of the influence of an entire offshore reef system on ocean wave transmission. The researchers used a 16-year record of satellite altimeter measurements of wave heights.

The team was led by Dr Shari Gallop, Research Fellow in Geology and Geophysics at the University of Southampton, and included Dr Ivan Haigh, also from the University of Southampton; Professor Ian Young, Vice-Chancellor of the Australian National University (ANU); Professor Roshanka Ranasinghe, Professor of Climate Change Impacts and Coastal Risk (UNESCO-IHE, Deltares, ANU), and Dr Tom Durrant (Bureau of Meteorology, Australia).

The aim was to see how wave height reduction is influenced by the porosity of the reef matrix, sea level and wind speed. Dr Gallop says: “There was no evidence that in less porous areas wave heights are lessened. This is because individual reefs, like islands, cast a ‘wave shadow’ over a large area, so that a matrix of individual reefs is remarkably efficient at reducing waves.” ....

The Great Barrier Reef, shot by Sarah Ackerman, Wikimedia Commons via Flickr, under the Creative Commons 2.0 license

View on Private Sector: Insuring against climate change

Aamna Modhin in SciDev.net: A recent UN report said that global warming will cause trillions of dollars of damage to coral reefs in the Caribbean. It also warned that small island states will be disproportionally affected by the impact of climate change: their coral reefs, which their economies depend on, are under significant environmental stress.

One news report on the document noted that the insurance industry could play a role in safeguarding such nations’ economies by providing stronger theoretical frameworks in which to understand risks to reefs.

I asked Mike Maran, chief science officer at insurance firm Catlin Group, what such efforts might look like. He tells me the firm is sponsoring a global scientific survey of coral reefs, including some in the Caribbean, with the aim of monitoring their health over the coming years.

Why would an insurance company do such a thing? Maran explains that scientific evidence helps insurers understand what might happen to reefs in the future, and how fast. Although firms do not insure the reefs directly, Maran says they have a broad obligation to study the risks society will face in the future so as to understand and manage those risks. The collection of robust scient
ific information gives insurers a good understanding of how the planet is changing and the impact these changes will have on policyholders.

Many of the risks involved in policies firms do provide — for example insurance for homes, other properties and businesses — could be linked to climate change, and so understanding changes to reefs as a proxy measure of that will help quantify those risks. For example, reef degradation could have an impact on fishing or tourism industries and so indirectly change the value of insured assets....

A coral reef in Biscayne National Park in Florida, shot by a Park Service employee

Australian environmentalists welcome bank wariness on reef port

PhysOrg: Environmentalists on Saturday welcomed Deutsche Bank's reluctance to invest in a major port expansion near Australia's Great Barrier Reef, saying it reflected global concern about the project. Australia gave the green light to the major coal port expansion for India's Adani Group at Abbot Point on the Great Barrier Reef coast last year subject to strict environmental conditions.

But conservationists slammed the approval, warning it would hasten the natural wonder's demise given it is under pressure from climate change, land-based pollution and crown-of-thorn starfish outbreaks. At its annual general meeting in Europe on Friday, Deutsche Bank said its policy for dealing with activities in or near World Heritage Sites ruled it out of investing in Abbot Point.

"Deutsche Bank does not support activities when the government and UNESCO do not agree that the planned activities do not place the exceptional universal value of the site at risk," the bank said. "As we have seen, there is currently no consensus between UNESCO and the Australian government regarding the expansion of Abbot Point in the vicinity of the Great Barrier Reef. Our policy requires such a consensus at the least. We therefore would not consider applications for the financing of an expansion any further."

UNESCO has stated concerns about coastal development proposed in the region including port and coal operations, with the body expected to discuss the issue at a meeting in June.

The Australian Marine Conservation Society, which is campaigning against the port expansion, welcomed Deutsche Bank's stance, which it said showed global concern about plans to "industrialise the coastline of the Great Barrier Reef"...

Helicopter view of the Great Barrier Reef, shot by Nickj, Wikimedia Commons, licenseed under Creative Commons 3.0 

Reef fate in hands of chiefs and researchers — for now

Jan Piotrowski in SciDev.net: Trust and strong relationships between researchers and traditional tribal leaders of small pacific islands allows for quick and effective implementation of science-based strategies that slow the decline of coral reefs, an international conference has heard.

Coral reefs recovered far quicker when scientists worked directly with leaders of local communities — rather than national governments — on changing the damaging land-use practices that pollute coastal waters, said Robert Richmond, a professor of marine biology at the University of Hawaii, United States.

...But these strategies can only be a stopgap as the rising sea levels, water temperatures and acidification — which could spell the end for many reef ecosystems — will need to be addressed by an international climate change agreement, he said.

For local populations dependent on ever-diminishing coral reefs for survival, conservation laws take too long to devise, and are difficult to enforce and monitor in remote regions, Richmond tells SciDev.Net.

Local chiefs have the ability to quickly change damaging practices but researchers must first work to build trust before their advice will be considered, he adds. “Many times, the local level is much more efficient than national governance. Working at a local level means communities can act immediately,” Richmond says....

Hawaii's Pearl and Hermes atoll, US Fish and Wildlife photo

Human deforestation outweighs climate change for coral reefs

University of Western Australia: Better land use is the key to preventing further damage to the world's coral reefs, according to a study published this week in the online science journal Nature Communications. The study, by an international team including a researcher from The University of Western Australia's Oceans Institute, has important implications for Australia's Great Barrier Reef.

The study authors write that preventing soil erosion and sediment pollution arising from human activities such as deforestation are crucial to reef survival.

The study - ‘Human deforestation outweighs future climate change impacts of sedimentation on coral reefs' - looked at the effects of future climate change on the hydroclimate of Madagascar's reefs and different deforestation scenarios.

"The findings are very relevant for Australia since intense land use and past deforestation have transformed the river catchments tremendously and are seen as a major threat to coral reefs in the Great Barrier Reef and elsewhere," said Dr Jens Zinke, of UWA's Oceans Institute.

"Managing hinterland land use is the major action needed to buy time for corals growing near rivers." Dr Zinke said the study looked at four watersheds near coral reef ecosystems in Madagascar, which has different climate zones that mimic most of the world's coral reef climate and a range of different land uses...

In the Great Barrier Reef, shot by Steve Evans, Wikimedia Commons via Flickr,  under the Creative Commons Attribution 2.0 Generic license

Great Barrier Reef coral halved in 27 years

Amy Coopes in AFP: Australia's Great Barrier Reef has lost more than half its coral cover in the past 27 years due to storms, predatory starfish and bleaching linked to climate change, a study found Tuesday. The research by scientists from the Australian Institute of Marine Sciences (AIMS) and the University of Wollongong warned that coral cover on the heritage-listed reef -- the world's largest -- could halve again by 2022 if trends continued.

Intense tropical cyclones -- 34 in total since 1985 -- were responsible for much of the damage, accounting for 48 percent, with outbreaks of the coral-feeding crown-of-thorns starfish linked to 42 percent. Two severe coral bleaching events in 1998 and 2002 due to ocean warming also had "major detrimental impacts" on the central and northern parts of the reef, the study found, putting the impact at 10 percent.

Two-thirds of the loss had occurred since 1998, with the rate of decline increasing substantially and only three of the 214 individual reefs surveyed across the sprawling 345,000 square kilometre site escaping any impact. "This loss of over half of initial cover is of great concern, signifying habitat loss for the tens of thousands of species associated with tropical coral reefs," the study said.

Author Hugh Sweatman said the findings, which were drawn from the world's largest ever reef monitoring project involving 2,258 surveys over 27 years, showed that coral could recover from such trauma....

A giant clam in the Great Barrier Reef, shot by Janderk, public domain

DNA evidence shows that marine reserves help to sustain fisheries

EurekAlert: Researchers reporting online on May 24 in the Cell Press journal Current Biology present the first evidence that areas closed to all fishing are helping to sustain valuable Australian fisheries. The international team of scientists applied a forensic DNA profiling approach to track the dispersal pathways of fish larvae throughout a network of marine reserves on Australia's Great Barrier Reef.

"Marine reserves have been set aside to create resilient ocean ecosystems and help sustain fisheries, yet there has been little clear evidence that they can provide either," said Hugo Harrison from the ARC Centre of Excellence for Coral Reef Studies and James Cook University in Australia. "This study provides the first conclusive evidence that larval supply from marine reserves generates important recruitment subsidies to both fished and protected areas."

..."Until now, no one has been able to show that adequately protected reserve networks can make a significant contribution to the replenishment of fished populations," said Geoff Jones, lead author of the study. "The fate of the offspring of fish in the reserves has been a long-standing mystery. Now we can clearly show that the benefits of reserves spread beyond reserve boundaries."...

Photograph by DM289169, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license