REGENERATION
Sponges have a great regeneration capacity, with the ability to repair wounds and restore lost parts via stem cells (Degnan et al 2010). Species vary with their ability to recover from, and resist damage. Traits that may increase the A.queenslandica resistance and recovery include low profile, resistant skeletal material, cryptic habitat, rapid growth rate, quick reconstruction of surfaces, and the ability to reattach to any surface and reorganise for efficient water pumping (Wulff 2006).
Whilst on Heron Island from in September 2010 an experiment was conducted on A. Queenslandica, assessing regeneration after wound induced stress The aim of this experiment was assess the rate of regeneration once wound stress had occurred. A similar study was conducted in 1990 where reduction and regeneration in several sponge species was observed. Full recovery was observed to some of the choanocycte chambers after only 12 hours of the stress being removed (Francis et al. 2009).
Specimens were collected using a bucket, filtered saltwater tank set-up, identification resources for A. Queenslandica, chisel and hammer and reef walking shoes and gloves. Lab analysis was conducted using a microscope with appropriate lighting, microscope camera with installation software, spare microscope light bulbs, a laptop, plastic container, scalpel, several A. Queenslandica specimens and seawater.
Sponge specimens were collected by walking out to the reef flat at Shark Bay, Heron Island, whilst wearing appropriate footwear and gloves, and turning over coral rubble until specimens matching the classification resources were identified. A chisel and hammer were used to separate the piece of rubble containing the sponge, then placing in a bucket full of seawater ensuring the sponge was submerged at all times. The specimens were taken back to the lab as soon as possible and placed back into filtered tanks.
The lab analysis was conducted by firstly placing the sponge specimens in a plastic filled with seawater to ensure no exposure. A very thin slice (1-2mm wide) was sliced off with the scalpel, using the weight off the scalpel and not applying extra pressure to the scalpel causing further damage. There was also care taken not to squeeze out cells or rip off tissue, as this is needed for regeneration. The sliced specimen was then placed under the microscope, setting the microscope camera to a time series to take a picture every 30 minutes for 12 hours. This time series was then repeated another times. Samples were also taken from another specimen and placed in 70% ethanol to set and preserve for genetic analysis.
Data Analsis was conducted using visual interpretation to assess the speed of regeneration over a 36hr time period
- First 12 hours;
http://www.youtube.com/watch?feature=player_detailpage&v=Es4hD34AJac
- 24 hours;
http://www.youtube.com/watch?feature=player_detailpage&v=3J2Oti8K3bA
- 36 hours;
http://www.youtube.com/watch?feature=player_detailpage&v=71GicK1tSWs
As this experiment only used visual interpretation it was not thought to be very successful, but may lead to further studies with more quantitative analysis. There were also problems associated with computers, light bulbs and the movement of the bench the experimental set-up was placed on. The specimens also didn’t seem to be doing as well as expected in the tanks, which may have been due to direct sunlight. If further analysis was to be conducted sponges should be kept in darker tanks and the lab analysis should be conducted in a separate lab where no interference can occur. The analysis should also be more quantitative, assessing the exact amount of surface area removed to know a more accurate rate of regeneration. A mathematical software program attached to the time series camera may be a way to do this. |