Taking apart ARMS step-by-step

1. Removing the ARMS structure from the water.
Image: Angus Livingston.


Monday 16 February 2009
ONE of the important tasks for the CReefs team on Lizard Island is the recovery of the Autonomous Reef Monitoring Structures (ARMS).
These reef-like structures were pinned to the ocean floor on the team's first visit in April 2008 and were designed to provide an environment for organisms to colonise.
The team responsible for examining the ARMS took one apart late last week and demonstrated the process they use to sample the biodiversity these structures collect.
Step one
The ARMS, which has been sitting in seawater with air bubbling through it to keep the animals living in it alive, is unbolted from the top. The pieces are removed and rinsed in a bucket to remove the mobile organisms, such as crabs or starfish.

2. Photographing the tray.
Image: Angus Livingston.


Step two
The plates are then photographed, top and bottom, with labels identifying them in the photographs. After that they are brushed over with a paintbrush into a bucket to make sure all the mobile organisms are collected.

3. The underside of the trays.
Image: Angus Livingston.


Step three
The plates, now only covered in sessile organisms like corals and bryzoans, are placed in ethanol to be preserved and examined later.

4. The various trays removed from the ARMS.
Image: Angus Livingston.


Step four
The water collected in the buckets is poured through various size filters to separate the larger and smaller organisms. The filters are then emptied into trays.

5. Filtering the organisms.
Image: Angus Livingston.


Step five
The trays are sorted through, with each organism collected and placed in separate cups.

6. Two trays of different sized organisms.
Image: Angus Livingston.


Step six
The organisms are placed in a tray for photographing, and then a small sample of their tissue is taken and preserved for DNA analysis.

7. Organisms sorted into cups.
Image: Angus Livingston.


Step seven
Finally, the organisms are preserved in ethanol so they can later be identified or re-sampled if necessary.