Cracks in the ice (good ones)

Today we swam to the other side of the McMurdo Jetty. This is the main site I have worked at for years and I wanted to see if there had been any big changes. Strangely enough there were much fewer of the faster growing sponges than the other side. In previous years we have seen outbreaks of Seastar Wasting Syndrome here and so I also wanted to see if there was an outbreak again (I didn't see any sick ones - so that is great).

The animal life on the seafloor is very similar to many other places but the crack along the top of the ice was more striking than the other side. This is the crack we have really enjoyed its variety from year to year, and this one didn't disappoint. Here is a worm tube (Feather duster/Sabellid polychaete) with tons of anemones growing on it, and then a sponge (Isodictya) and an inquisitive fish keeping an eye on me.

While there were more of the fast growing sponge on the other side of the jetty, some was still here. You can see why it is not a long lives species with three seastars eating it. These are the top predators here.

Looking back to the hole (which seems much farther away than it is) there is even more kinds of invertebrate diversity. Including a sea spider for good measure. When people talk about a lack of life in Antarctica, they are very much not talking about the ocean floor.

While there is less life in the water, much of it is still striking. Plus the lack of much phytoplankton is why the water is clear enough for the images here.

ROV and penguin encounters

We spent our last two days back up at Evans and working hard to get as many samples of different kinds as possible. It was another wonderful trip.

We don't always get to dive out of the comfort of nice big dive locker but are living pretty good life with our dive tomato. This hut is on skis and is light enough that we can tow it around. The hole in the bottom we can dive through and then at night we hang our drysuits as you see to make sure that the feet are not totally frozen for the second day of diving. We then go camp in tents, we can also get this structure pretty hot with the heater on the far side.

We are working with a small ROV that the Kiwi scientists are very adept at using. That means they go find the site and then the ROV leads us to it. It can survey in a day what would take divers a long time and it has been incredibly helpful to us. The shot at the top of the page is us working with it to collect samples from the seep it found.

Just after our dive, we had some more visitors. They hung around for a long time to the point where we just had to wander away and get back to the science. We never approach birds and mammals here because of the Antarctic Treaty. However, they haven't read it so just come right over to do what they want around the camp.

Another just amazing day in this windy and cold, but beautiful place.

Diving a new site and new Seeps!

Much of this years project is looking for new areas where methane is seeping from the seafloor. Our aim is to understand what is eating the methane and keeping it out of the atmosphere. Here we are focusing on areas like the one to the right which have active methane released from the seafloor leading to that white color. The white is bacteria that eat Sulphur that is a bi-product fo the microbes that eat methane. This is a new site that we just found this year!

Here are Alex and Steve collecting images of the site as we scope it out. Our New Zealand Colleagues found this and then guided us to it. There were many more sites that they also found that we hope to dive on over the next week.

This site has a lot more light so there is algae including the coralline algae that it looks like the urchins and sea stars are eating here.

This includes fleshy red algae such as above, but it lives in the shallows so can be impacted by ice.

Here is some anchor ice that is having a tug-of-war with the algae. The ice is trying to float away and the algae trying to stay. In the ice algae there is a bunch of amphipods that live there. They also live in dense assemblages under the ice

Our bubbles disturb them and sometimes they swarm. Nice to be wearing a drysuit at times like these.

Here is the view up - nothing but brinacles, algae, and amphipods (so an active ecosystem under the ice.)

Overall a wonderful dive. The rest of the dives were working, so we didn't bring cameras and instead used the information we gained on this dive to sample the various new ecosystems discovered.