AUV Launch, Raglan Beach, and Whale Bay

This morning we got to sleep in because we were launching the AUV for a practice run in the morning. Around 10:30 we met up with our TA, Adam, and some other PhD students who were doing a practice launch of the AUV. AUV stands for Autonomous Underwater Vehicle, and it is a torpedo-like device that can be remotely operated from land or a boat.

Adam and Alex launching the AUV

The AUV belongs to the University of Delaware and was shipped the whole way here to NZ to help in some of the PhD research Adam and some of the others are doing. We were invited to the practice launch so we could learn a little more about AUVs and how they are operated so later on we could learn about the type of research they can help do. AUVs can contain a number of different instruments to measure different parameters in the water like temp, salinity, depth, and bottom profiling.

The AUV going off on its first NZ mission, a practice launch in a lake

After playing with the AUV, we got lunch on the road to Raglan Beach. Raglan is a cool beach because it is on the west coast so it has bigger waves, and it has black sand! The sand is black because it is close to the rock source, which is black, basaltic rock full of heavy metals. When this rock weathers away to form sand, it forms a black sand at first. Raglan is close to the source rocks, so it still contains this black sand. The heavier minerals cannot be transported as easily by wind and water so beaches further up the coast from Ragland (like 90 mile beach!) don't have black sand.

The black sand at Raglan

We dug a small trench so we could see the layering of darker and lighter sand, which we learned was from different concentrations of the heavy metals in the sediment. The waves at Raglan were pretty big and the wind was blowing like crazy, so it was not as much fun as the other beaches we have been to, but it was still pretty awesome. We only got to spend a little bit of time there since we spent so much of the morning with the AUV and we needed to get to our next stop at low tide. The next stop was Whale Bay, a rocky intertidal shore a little bit south of Raglan.

The rocky intertidal Whale Bay

We got there right at low tide so most of the rocks were exposed, leaving small tide pools full of organisms for us to see. This area was a coastal biologist's dream. We found a bunch of species of crabs, snails, limpets, and barnacles. Covering most of the rock was a black seaweed-looking plant called pseudolithoderma.

Pseudolithoderma- it was covering almost all of the rocks!

A sea star I found in one of the tide pools

Besides the great marine life, there was also another organism that littered the water- surfers! The waves here were great so we got to see a ton of surfers doing all sorts of tricks. Honestly, I am surprised there were so many of them out there because the waves were huge and going straight into a shore full of rocks!

A sweet surfer shredding a wave

This rocky intertidal environment was pretty awesome so we ended up spending a lot of time sitting on some of the big boulders. Art told us more about the geological aspects of the area and how this area was the source of the black sand at Raglan. Whale Bay has was are known as pillow basalts, which are huge dark rock formations made by lava erupting under water and cooling quickly. The pillow basalts weather to form boulders, which weather further into cobbles, which weather into sand, creating the black sand at Raglan. Isn't geology fun?! We splashed around a little more in the tide pools, but the tide was coming in quickly so we had to pack up and move out.

Thanks for the Keens, mom! They are perfect!!

On the long bus ride home, Art decided it was Karaoke time so we had a very interesting ride to say the least. Then it was back to the university for dinner and a relaxing evening.