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

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 

Great Barrier Reef report warns of cumulative effect of development

Oliver Milman in the Guardian (UK): The health of the Great Barrier Reef is declining and requires an urgent "net benefit policy" to ensure development along the Queensland coast does no further damage to the vast coral ecosystem, according to a major government assessment.

The Great Barrier Reef strategic assessment warns that the reef faces numerous threats, including erosion of water quality, a plague of crown-of-thorns starfish and climate change, which is described as the "most serious long-term risk facing the reef".

The Great Barrier Reef Marine Park Authority's report, which analysed the health of the World Heritage-listed marine park area, identified the need to reduce sediment, nitrogen and nutrient flows onto the reef. A parallel report, conducted by the Queensland government, looked at the condition of the coastline alongside the Great Barrier Reef.

The marine park assessment states that "urgent and effective" intervention is required. It proposes that a "net benefit policy" should ensure coastal activities produce an overall benefit to the reef, with more focus on the overall impact of human activities and weather events such as cyclones, rather than individual events....

A satellite image of the Great Barrier Reef, from NASA