Dive_Blog_2024_11_08_AS1
Purpose: Watching El Nino Underwater TLC and sensor recovery and deployment.
8 Nov 2024
Dive_Blog_2024_11_08_AS1
Post-Trip Dive Report
Purpose: Watching El Nino Underwater
08 November 2024
By: William Hagey
Here’s the video made from our time-lapse camera over the past two months:
Location: Point Loma – Acoustic Site 1 (AS1)
Vessels: The Keltic Knot
Topside Support: None
Divers: William Hagey, Paul Rahilly, and Jim Melrod
Surface conditions: Flat calm, sunny and warm. A day of summer in November.
Visibility: 20 at the surface, and about 20 feet at the bottom
Temperature at depth: 53° F
Current: No current at the surface and the bottom.
Dive #2: Time in: 12:23 PM, Dive length 37 minutes.
Depth Max: 66 ft
Purpose: To replace the TLC camera, conduct a video transect, take photos and videos, and make observations.
Summary: We swapped out TLCs with O2 sensors and did a video transect. Videos were taken by W Hagey with GoPro and a couple stills with my Olympus. Jim Melrod, took stills.
Equipment Notes: There had been no big swell during this deployment so the camera was where we left it.The UVC had no corrosion, but the zinc, which was larger than last time, was well used. I will need to make sure to replace the zinc. The slave light and UV-C light system on this unit is the original kind with potted splice on the endcap. So it is possible that the other four units have a galvanic issue.
TLC PMRG 3 with MiniDOT 766000 was recovered. The TLC was set at a 15 minute interval with and O2 readings were set for every ? minutes. The UV-C light worked for the whole deployment and there was an obvious area around and including the window that was clear of fouling. The UVC light works. Now, we need to make sure it does not corrode. The batteries seem to be holding up well through these deployments.
Habitat characteristics and surveys:
The habitat seems healthy and the lower and upper story kelp continues to grow and thicken. There is a lot of Stalked kelp (Pterygophora californica) both young and adult. The elk kelp (Pelagophycus porra) continues to have young individuals growing.
Methods: Jim took photos and I took videos and a couple stills as we did our work. I swam a 50 M transect.
Transect: We swam a 50 meter transect at 300 degrees magnetic with my new GoPro cam. There was Ptaragophera and Pelagophycus scattered in the transect.
Abalone: I didn’t see any, but I was busy and not looking.
Dive Details: Note: I used the new GPS waypoint, and Paul held the boat right on location as the anchor went down. As a result the anchor line went right over the top of the TLC. I would guess that the GPS waypoint is about 3 meters north of the TLC. A perfect waypoint. The yellow painted paver and brick near the camera helped us find it easily. There is a larger brick with holes in it there. It is like the ones used in lobster traps.
This is good because 4 days later a commercial diver found the TLC and picked it up. The bricks will make it easier to find the location to place it again. There is a fun story here.
These are images from the past three deployments. The latest one is on top. The camera is aimed a little lower than I would like on the previous one. But, thanks to the camera being brought up by a commercial diver on Sept 23, we may be able to place it better. It was tilted a little higher, and I did rotate it to the right a little with the hope of having some more of the kelp in the background. Unfortunately it is also rotated a little.
This is a plot of the oxygen and temperature measurements for the deployment. Notice the flat line after about the first week. This is where the commercial diver had collected the TLC. We were able to get it back out in about a week.
