Studying the small - Bryozoa


Kevin Tilbrook examines one of the many samples collected from the Ningaloo lagoon.
Image: Gary Cranitch

 

Kevin Tilbrook, an independent researcher linked to Natural History Museum of London as scientific associate, works with an often overlooked group of animals in the ocean known as the Bryozoa.
 
Bryozoans are commonly known as lace corals or moss animals.
 
"Each colony consists of a group of individuals," Kevin said. "They're asexually budded one from another so they are all genetically identical.
 
"Colonies can form large intricate structures which bear no resemblance to the structure of the individual."
 
He said that he, like the other researchers on the CReefs trip, was at Ningaloo to do an inventory of the species in the area.
 
He said it was good to be able to collect the samples, (he looks at rubble, shells and rocks) even though he will not to be able to work the information fully, as he doesn't have an official posting or funding for further research. The samples he has collected will go to a retired bryozoan expert in Melbourne, and they will work them up together.
 
Kevin said his ability to access the deeper sites had been hindered partly by the weather and only being able to search while snorkelling on this trip.
 
He said he has recognised 95 per cent of the species that he had come across here.
 
Many of his samples had come from the lagoon but he thinks there may be more species on the outer reef. He said there was the possibility that there was more diversity to be detected if he were to collect samples from greater depths and other locations.
 
There are some species Kevin said he would expect here, but so far he has not yet found them.
 
"It may be phenomenally diverse; I don't think it is, my gut feeling is that it is not as diverse as the Great Barrier Reef. But it is interesting for the fact that it isn't diverse," he said.
 
"It may be because we are getting to the bottom of the tropics that we are not finding the tropical bryozoans I would have expected to find.
 
"But as there is so little known about tropical bryozoans it is hard to generalise about numbers.
 
"It is a good starting point for Western Australia," he said.
 
He said he was looking at a three inch shell that Magda had collected for him which carried about eight species on it, and added three species to his list. "That shell was from a different place, a different depth, it is about trying to get samples from as many and varied places as possible".
 
Typically, he said, he waited for the items collected from the reef floor to dry before looking at them.
 
"The whole rock glistens when it is wet, making it difficult to differentiate the bryozoans but when it is dry, only the bryozoans glisten, because they have an organic layer over the top of them," he said.
 
He said while he was at Ningaloo he would try a technique used by a colleague which involved adding food colouring to the water they were kept in. This method was meant to highlight the colonies when wet.
 
In WA he has been looking at the specimens under a microscope, but when back in the laboratory he would use an electronic microscope. This makes telling the species apart easier as the distinguishing characters are so small and only really visible at high magnification.
 
He said he was looking at a three inch shell that Magda had collected for him which carried about eight species on it, and added three species to his list. "That shell was from a different place, a different depth, it is about trying to get samples from as many and varied places as possible".
 
Typically, he said, he waited for the items collected from the reef floor to dry before looking at them.
 
"The whole rock glistens when it is wet, making it difficult to differentiate the bryozoans but when it is dry, only the bryozoans glisten, because they have an organic layer over the top of them," he said.
 
He said while he was at Ningaloo he would try a technique used by a colleague which involved adding food colouring to the water they were kept in. This method was meant to highlight the colonies when wet.
 
In WA he has been looking at the specimens under a microscope, but when back in the laboratory he would use an electronic microscope. This makes telling the species apart easier as the distinguishing characters are so small and only really visible at high magnification.