Dive_Blog_2024_08_06_SSS1

Purpose: Watching El Nino Underwater TLC and sensor recovery and deployment.

August 6, 2024

By: William Hagey

Our fearless, although at least in my case, not flawless, crew. From left to right, Glenn Hefner, Jim Melrod, Ronan Gray and Bill Hagey. Welcome Glenn and we wish you luck with your studies at UC Berkeley – we hope you can join us again soon! 

Point Loma – SSS1

Vessels: The (Mighty) Kelpfish

Topside Support: Glenn Hefner.

Divers: William Hagey, Ronan Gray (Jim had to miss this dive to help the team. Sorry about that Jim.)

Surface conditions: 1 to 2 foot mixed swell, sun burning through earlier fog.

Visibility: 30 ft (The water was ocean blue and full of salps – I’ll explain and show.)

Temperature: 52° F

Current: Very mild.

Dive: Time in: 10:38 pm, Dive length 49

Depth max: 57 ft

Purpose: Deploy and Recover TLCs – and try to do a transect.

Summary: With the visibility way up and the plankton bloom over we could more easily see the environment. There is a lot more Macrocystis, it is young and easy to get tangled in. There was a lot of lower story brown algae too, including Laminaria and Desmarestia. W Hagey got photos and video with his Olympus and new GoPro. Ronan shot video and edited it here:

Here’s a link to a video Ronan made of our dive:

August 6, WENU Project Dive 2 (youtube.com)

Equipment Notes: TLC PMRG 3  with MintDOT766000 were recovered. Both collected full sets of images and data. A wiper successfully kept the window on the TLC clear. The UVC anti fouling light was attached to the top of the TLC aimed down at it as a test. To our surprise the fused silica tube of the UV-C light was shattered. We suspect a large sheephead was the cause; maybe he thought it looked interesting. The battery for the UVC LED and the salve LED light was 14.8V at 5AH made with two batteries that were diode-OR’d together. It is unclear if the UVC light stopped biofouling since we don’t know how long it was on. The replacement TLC is using a UV-C light aimed at its window with a duty cycle of 30 seconds every 6 hours. 

Here’s a link to the time-lapse video:

2024 06 04 Thru 2024 08 06 USA CA SSS1 (youtube.com)

Habitat characteristics and surveys: Salps galore! What a neat experience!! No proper transect was done because Ronan and I were simply trying to get our bearings on this site again. He found the TLC quickly, but our first attempt to find the wreckage failed. Ronan tried again and found it this time. I tried to get a magnetic heading, but had no luck because my new GoPro has strong magnets and was mounted right next to my compass. We did, however, confirm that the TLC is 32 meters from the wreckage. 

We did record videos as we looked for the wreckage which will act as transect videos. There is a lot of young macrocystis beginning to grow in this area. (The ghost town is growing again!) It 

has larger gas bladders and looks more like what I’ve seen around Catalina. It can be seen in the transect videos. A lot of Laminaria was in the lower story. The bottom was pretty well covered with it. This is in addition to the brown algae that I’ve seen here before, it is evidently transitory and not a good food source.

Methods: I believe we have a good anti fouling solution with the UVC lights going on for 30 seconds every 12 hours. For this deployment we went up to every 6 hours, just to be sure. We sent up a float from the wreckage and I believe we have a good GPS way point on it now.  We need to get a GPS hit for our original ground zero where the zig-zag block is. This will help a lot with transect videos in the future.

Abalone: I saw some adult reds in the wreckage along with some shells. One shell is kind of a home for a gopher rockfish. . The only other adult red was the one in front of the TLC. 

Dive Details: Only Ronan and I dove. I forgot my mask and Jim Melrod was such a great team player that he let me use his mask even though he had to forfeit this dive. The water was ocean blue from the surface to the bottom. There were salps throughout! It was like diving back into a sea from 200 million years ago… see pictures below. On our second attempt we found the wing. I sent up a float and I think we got a good GPS fix on it. We will try it next time. 

ADD link to TLC video

These are salps. The upper image shows a colony and the lower one is an individual. They come into our waters about once a decade.

The top image is what it looked like when we recovered the TLC. Two months can be a long time underwater! The lower image is what it looked like when we left it. While this is not an award winning photo, it does show how things were set up. This setup has two lights, on the upper sides. The TLC we recovered had one light stalk that was straight above the camera.. Note the wiper is being used and the UV-C light is being tested on top of the TLC. We took pictures before deploying the camera so we could get a before and after comparison.

The top is an image from the TLC from the previous deployment The bottom image is from the most recent deployment. We are working on aiming the cameras the same between deployments. Notice how the abalone is lifted pretty high off the rock. This is its “ready to capture drift kelp mode”. It is not exactly a pounce, but somehow, in a trick that I don’t understand, they are able to grab kelp as it drifts by. Just imagine trying to do this, without fingers, arms or even teeth!