Reef Report for Friday, June 22, 2007
Research Sheds Light on Impact of Land Use on the Reef
Results support farmers call for land use education.
The study by researchers from the ARC Centre of Excellence for Coral Reef Studies (CoECRS) focuses on the hundred-year history of coastal development around the cetnral Queensland town of Mackay and its impact on nearby coastal coral reefs, which have been gradually disappearing.over the past 100 years.
The land area they focused on was the watershed of the Pioneer River.
This areaís history is well known, and two key events on land were documented when the researchers analyzed the chemical composition of corals found offshore.
Large coral heads grow outward very slowly, add layers much like those of an onion. A researcher can analyze the chemical composition of the coral as it grew through the past century by looking at different depths of a thin sample of coral taken from the outmost living ring to the very oldest parts, deep in the core of the coral head.
What these researchers found was that nutrient releases caused by land based activities could be found in these corals. The old parts of the coral contained nuttirents released from the clearing of the forests for agriculture that took place 100 years ago, Parts of the coral dating from the 1950ís and onward contained nutrients matched the first large-scale use of chemical fertilziers during this time.
While itís long been thought that land use practices had an impact on coral reefs in Australia and elsewhere, this is the first clear connection that has made.
While it clearly demonstrates this process at work in the Pioneer River drainage, the history of land use practices up and down the Queensland coast is very similar, and itís likely that they have had a similar impact on those sections of the Great Barrier Reef.
While thatís all history, how can this research guide the development of land use practices that better protect the Great Barrier Reef? To some extent that is already happenning as state and federal governments several years ago released a plan that focuses on monitoring and improving the quality of water in the rivers that drain land adjacent to the Great Barrier Reef.
In the Cairns area a catchment plan for our largest local river, the Barron River, includes reestablishing the bands of forest land that bordered the river, which acted like a living filter to trap nutrients and prevent them from rinsing out of the soil, into the river and onto the reef.
The research also supports the requests of farmers, who are lobbying for funding of an educational service that will help them develop more reef-friendly land use practices, which will act to reduce the runoff of nutrients from farmlands and eventually end up on the Great Barrier Reef. We hope to see this program fully funded, but wonder if in the long term that savings from more efficient use of fertilizeers (because of better land use practices that keep fertilizers in the crops and prevent them from draining off land and into the rivers) may save enough money to pay for keeping the education program going.
Coverage of this story, from UQ News Online
The ARC Centre of Excellence for Coral Reef Studies
Farmers Request Assistance for Land Use Practice Education
The weekly reef report is written by Joel Groberg of DiveTheReef.com,
who compiles them from the many conversations he has with dive staff in the area, as well as† many other local sources in the dive
Index of all reef reports.