Magic carpet brings worms to the surface



Lynda Avery conducts a grab from the ocean floor.
Image: Gary Cranitch

 

Monday 23 November 2009
 
CReefs Australia's polychaete biologists are using an unusual method to collect samples.
 
Known as the "magic carpet" technique, a small plastic tarp is secured to the ocean floor with a heavy chain to cut off oxygen to the area underneath by preventing water flow.
 
Senior Principal Research Scientist at the Australian Museum in Sydney, Pat Hutchings, said the area of ocean floor selected for the technique "looked like a desert" when snorkelled over, but the sediment contained animals beneath the surface.
 
"The theory is that you reduce the oxygen content of the sediments, bringing all the animals to the surface," Pat said.
 
Some hours later, the plastic sheet is carefully peeled back and the animals at the surface of the sediment are gently gathered into a catch bag.
 
Polychaete consultant Lynda Avery, an associate at the Museum of Victoria, said the polychaete species collected were then divided up into taxonomic families and sent off to members of the polychaete team to examine.


Kareen Schnabel and Lynda Avery collect samples from underneath the magic carpet.
Image: Gary Cranitch

 

From the polychaetes collected from the magic carpet laid during this field trip, Lynda is studying Opheliids;Senior Principal Research Scientist at the Australian Museum in Sydney, Pat Hutchings, is examining Terebellidae and Museum and Art Gallery of the Northern Territory Chris Glasby is examining Nereididae. Polychaete expert Charlotte Watson, also of the Museum and Art Gallery of the Northern Territory, is assisting the team.
 
Lynda said the method had produced "very good" results when used during a CReefs Australia field trip to Ningaloo in May, but this time had not worked as effectively.
 
"But we'll wait and see the final results," she said.
 
Lynda also used the traditional method of collecting by "grab" nearby to the magic carpet site in order to gather a different set of samples and allow her to compare the results of the two collection methods.