Aug 082011


About the dive

The eagle eyed may have noted an extra diver in the background of the last Piccaninnie Ponds shot I talked about here. The little white speck in the distance is actually a diver heading into the usually-forbidden depths of the cave. The photo was taken on a weekend reserved for research into some of the more unusual aspects of this unique wetlands and cave site.

In particular, the team was checking on salinity monitors that had been installed in the cave on a previous project weekend. Piccaninnie Ponds is just over the sand dunes from the ocean, and a reduction in ground water flows following the recent drought may lead to salt water incursion from the ocean into the system. This is more likely to happen at deeper levels, but with spring water creating a flow from the bottom of the system to the surface, salt water entering the bottom of the cave could have serious impacts on the wetland ecosystem.

The deepest salinity monitor has been installed at 95m, in the area known as the Chamber of Secrets at the very bottom of the cave. Above this, there are further monitors at 40m, 20m in the saddle between the Chasm and the Cathedral, and near the surface. A solar powered logging station seen in the second photograph below is anchored at the surface to collect the data and transmit it for study.

Cormorant on the monitoring station

A further point of interest being investigated is the noted flow coming out of the bottom of the Cathedral. Known as the bathtub, a diver using a sidemounted configuration (and with the appropriate government permits) can move into the very tight, twisting and silty area below the Cathedral. On this dive, Jim and I were both familiarising ourselves with this challenging area and hoping to retrieve a reel previously deposited. Despite my original intentions to explore without being hampered by a camera, I’d decided a chance to capture some images was too good to pass up.

About the photo

After moving through the first vertical squeeze with Jim following me, I retreated off the line to get a shot of Jim passing through. You can see the orange line running through the shot. The shape of the vertical fissure made strobe placement very tricky, with the wide angle lens making the cave look deceptively large at this point. Silt raining down meant there wasn’t going to be very many photographic chances. Upon clicking the shutter for the first time, I discovered a further challenge – the camera shutter clicked once, but the two attached strobes fired 8 to 10 times, as soon as they recharged.

This meant a very long delay between feasible shots, as I wasn’t able to co-ordinate the automated strobing with my shutter clicking. Taking a shot between the 8 flashes meant the strobes hadn’t recharged, and without light all the camera could capture was blackness. On the other hand, waiting until the end of the 8 strobe series was causing some confusion with my model. Complications were added by the off camera strobe Jim was carrying, which was being triggered by some of the repetitive flashes but not all.

After three attempts at photography, and having examined the woeful results on my camera screen, this equipment malfunction led me to wrap the camera up and leave it on the line for retrieval on exit. The culprit was later discovered to be water in the connector between the strobe cable and housing bulkhead, and luckily no permanent damage was done. Reviewing the attempted pictures afterwards, this shot appealed to me for giving a good sense of the challenge of this area of the cave for photography.

I liked the scalloping on the walls, which is more pronounced as you move deeper into the cave. The off camera strobe has given a blue tinge to the clear water below, glimpsed through the limestone projections. This image also gives a small idea of the spiralling nature of the cave at this point, which makes it very difficult to reference up and out. Not a place to lose the line, but a very interesting one to explore.

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