Dive_Blog_2024_11_08_AS2

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

8 Nov 2024

Here’s the video made During our dive:

Here’s the video made from the time-lapse images from the previous two months:

Report by: William Hagey

Point Loma – Acoustic Site 2 (AS2)

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: 54° F

Current: No current at the surface and the bottom.

Dive #1: Time in: 9:53 AM, Dive length 39 minutes.

Depth Max: 72 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. Jim Melrod, took stills macro.

Equipment Notes: 

TLC recovered notes: 

The camera was where we left it. It was about 15 meters to the northeast from where we dropped anchor. PMRG 1 with DOT 697549 was recovered. Full sets of data were recorded from the TLC and the O2 and temperature logger. The UV-C light was not corroded like the previous four units. This may be because it was wired differently and there is no ground to electrolysis or it may be because of a larger zinc. I’ll be sure to install a similar size zinc next time and it should be fine.  The camera has been tilted up during the deployment. It turns out that something had done this about half way through the deployment. It was not during a storm. I’ve seen this happen from a  curious harbor seal. But I didn’t see anything in the images. 

Deployed TLC notes:

We deployed NOAA 2 with a UV-C light that had all of it’s exposed aluminum parts cast in epoxy to protect it from corrosion. 

Methods: Jim took stills working on macro images that I’ll share in this report and hopefully in the video. I recorded video with my GoPro with a dive light and took a still of the TLC. Paul stayed near both of us as a safety diver. I swam a 50 meter transect at 300 degrees magnetic. I used the compass on my slate 

Habitat:The habitat seems much the same as last time. It seemed healthy with a good variety. There may have been more lower story algae. The video transect may show this. 

Dive Details: The visibility was about 25 feet at the bottom with some particulates.

The adventures of the day: It was just a beautiful day! Sunny, calm, warm… like the best day of summer!

This is an image taken from this deployment. The camera was aimed a little higher to get more of the water in the background. These are senorita fish. When the camera was tilted up it looked like there were a lot of these guys. I wonder if they were spawning?

This image is from the July – Sept deployment with a sheephead and a juvenile rock fish. 

This is a plot of the temperature and oxygen for the last two months.