Day 8: 15 October

Day 8: 15 October

The final aim of the week was to deploy the deep towed imaging system (DTIS; see photo below). This is a camera that is lowered down to the seamount and towed along taking pictures every 20 seconds. We did 3 camera tows over Rumble III which provided some valuable images of the seafloor and the organisms (and lack of, in some areas) and helped explain some of our earlier results.

Along the transects it was clear to see that Rumble III was volcanic in origin, as are most seamounts, with pillow larva clearly visible. Below you can see individual coral colonies (the white ones are scleractinians and the orange ones gorgonians). Corals grow in areas of increased water flow, as they cannot move they must wait for the food to be delivered!

We had previously been disappointed by the lack of organisms collected in the beam trawls and sleds. However, when we sent a camera down we could see why. There was simply not a lot there! But we did see some nice critters including the squat lobster below

Can you see the squat lobster? Look more closely.....

Whilst seamounts can be hotspots of biodiversity they can also be inhospitable habitats. The picture below shows some of the inhospitable habitat on Rumble III. With lots of loose rubble to move around in the current there are no stable attachment sites for organisms like coral and the constant movement will crush many soft bodied organisms.

Once the camera was pulled up Tangaroa began the 48 hour steam back to Wellington.

In the last 5 days we have examined the water currents and tides in and around Rumble III, sampled the water column from 15m down to 3000m, collected some of the animals that live on the seamount and photographed areas never before seen. Once back in Wellington the samples will be distributed amongst marine biologists, chemists and physicists….the work has only really just begun.