Lake Merritt Underwater ObservatoryLatest update June 17, 2019 Started on July 4, 2018
Based at the historic Rotary Nature Center in Oakland CA, we intend to explore the underwater habitats and human impacts in an ever changing urban tidal lagoon. High school and community college students will define and document missions.
On Saturday June 15th, members of the original team of Oakland High School Environmental Science Academy OpenROV builders (2014-2016) --Tamia, Kahlil and Angela and their friend Khyri and fellow ESA alum Hoang--met at the Lake Merritt Boating Center to fly the Trident. They were joined by other members of the Lake Merritt Underwater Observatory expedition --Adrian and David--and the curious public. We all shared a common interest in the lake, underwater exploration and pitting our wits against electronics. Just after setting up we found out that the port motor was frozen solid! We were flying with only two out of three motors (we could only go up, down and to the right) but somehow we managed to capture a view of the underwater world.
Compared to the last video we made in this spot in early January, the lake floor community was much more abundant and diverse. There were Northern Sea Squirts and bright orange, red and green algae (maybe bryozoans) everywhere. I'm very proud of these young scholars and the amazing adults they have become. I'm looking forward to seeing and sharing the videos. A long day but a good one. So proud of us.-Katie Noonan
I decided to take my 2.8 ROV (the Grebe) on a last minute Sunday evening expedition to see if I could see a school of fish I’d seen earlier in the day. Can’t wait til we can see this with the Trident. Also hoping this year I can catch the Striped Bass hunting, and a bat ray (both of which I saw further up Channel earlier in the day)
Mother's Day - Under the lake! Underwater view of LMBC dock area 5-12
Crab is at 3:06 min/seconds and is in view for about 20 sec. Mud snails foraging at about 1:00 min/sec, striper at 6:20 min/sec. Location is under the short floating dock primarily. Video by Ben Stein from Laney College.
Here are photos of the BioBlitz dive team: David Wofford, Adrian Cotter, Nicole Guintu, Katie Noonan, David Almandsmith, Mike Connor, Trea Kines ,Kate Klingensmith and son and also Charles and his mom.
A big take-away: : Immediately you see more from the underwater view than from above. From above its all green and slimely looking with towers of fine filamented green algae (Cladophora?). Underwater you see patches of beige and rose, sheets of sea lettuce and a soft beige silt covering everything. Are we looking at a bacterial mat, eroded dirt, or a combo? You have to look closely to see the trash buried in the surface organic matter. Bay Pipefish=Syngnathus leptorhynchus There was more structure and patchiness visible than from above – there the plumey “cladophora stuff dominated. There were mussel clumps hanging below docks, from ropes?
Additional technical observations and questions: In viewing he video, I got seasick from up and down motion necessary to avoid smashing into soft bottom; slow versus fast motor speed helped. Problem of knowing scale….dust off a quadrat? It was hard to know the scale of objects in view. I missed the 10 cm. lasers as cross-eyed as they sometimes were. We might try experimenting with a quadrat. What is that beige stuff? Bleached and rotting seaweed or….Amathia?? not so soon for that. At times very murky looking out through >volume of water – even though the Secchi reading was quite clear. Lack of focus because camera was too far from the bottom was sometimes annoying. Probably more practice with the controller would help. I couldn’t find the pipefish in the 15 min segment so named… Smaller segments might make reviewing easier. We saw what appeared to be a mussel graveyard. There were small fish: schools of minnows, possible killifish,
Video from our BioBlitz on April 27th, 2019. It was an excellent little foray with half a dozen people taking a turn at driving. The lake bottom was busy with fish: killifish and gobis seemed everywhere, but in larger numbers on the sandy bottom. But we had two nice surprise visitors Bay Pipefish... surprise in that we didn't quite notice them while driving, but only in the viewing of video. We knew they were to be found in the lake, but not entirely sure they'd show themselves so readily.
We are going to meet in front of the Lake Merritt Boating Center docks around 10:30am PT and have an underwater look at the community of life in the lake.
Videos from our Lake Merritt Underwater Observatory dives in the summer and winter were displayed at the Grand Re-Opening of the Rotary Nature Center in Lakeside Park in Oakland CA on February 16th. Because of recent rains, the water clarity of <50 cm (Secchi) and the continuing rainfall made us decid eto postpone putting our new S.E.E. Trident in the water that day. We hope to do so soon.
Many thanks to OpenROV and to Nicole G. in Berkeley for helping us learn how to apply for the S.E.E. and how to operate the Trident. We are planning a new event in the next few weeks. This program will add a new dimension to natural history interpretation at the Nature Center.
A special thank you to Elks Lodge #003 in San Francisco for funds to purchase the accessories needed for operating the new Trident and making it accessible to a group of interested young people.
The most interesting thing about the video here, is perhaps what is not there. The mussels that dominate in this video were punctuated by anemones in my original one from this same location: https://vimeo.com/285059315.
The bed of the lake had much more on it... here it is empty.
The videos were taken from the same launching point near the Sailboat House on Lake Merritt where there is a series of floating and fixed docks.
This difference in the videos points to the seasonality of the slough as a whole: the fluctuations in salinity and oxygen because of the influx of fresh water... and also a unnatural aspect of Lake Merritt -- the time where the flood gates are most often closed, where the tide is not allowed in to refresh the lake.
Several of us met up with Nicole of OpenROV on Sunday Jan 27th 2019 to explore underwater at Lake Merritt. Many thanks to Nicole of OpenROV and Adrian Cotter for bringing out their remotely operated vehicles. Nicole showed us the new Trident ROV which was amazingly fast and maneuverable. Adrian's 2.8 model got beautifully clear views from time to time as it cruised more slowly.
The expedition was quite successful. We saw lots of red seaweed and mussels and some sunken trash with everything kind of blanketed in beige silt. Lake Merritt is a tidal lagoon connected to San Francisco Bay by a short channel. It receives fresh water from urban creeks and stormdrains. The lake was still brackish on Sunday even after all the rain (24ppt top/27 ppt bottom) and dissolved oxygen (7 ppm). Thanks to Tamia, Davonte, Mike, David and several passersby for assisting with the project. More photos of the day at : https://www.flickr.com/photos/ohsesa/albums/72157704809555041
Major thanks to Adrian Cotter for sharing his expertise and his OpenROV with us. The video really shows the potential for ROV's to show the underwater community. I made a "log" for Adrian's video so that we can begin to record species and habitat observations, and easily locate them in the 14 minute tape. I look forward to the next dive. Thanks to everyone who came out. We can use this experience to plan for a grand reunion maybe this fall. Photos from August 12th here:
DIVE LOG –August 12th 2018 - Adrian’s OpenROV
TIME Total time is 14 min
0:00 Tube worms (Ficopomatus emigmaticus) and yellow sponge with long tubes (oscules) extended(Halichondria bowerbanki). Beige brushy stuff is bryozoans and mud tubes from polychaete worms.
0:21 Sea anemones with tentacles extended – 2 light strips on barrel identifies as Diadumene lineata. Form with orange strips also seen elsewhere.
1:02 ROV heads under the dock. Mussels and sponges.
1:26-1:31 A crab on a pillar. Shape and position suggest green shore crab (Hemigrapsus oregonensis).
2:30 Close-up of mussels and anemones, brushy bryozoans. A lot of “marine snow.”
3:17 break, then shifts to travel over yellowish-beige seaweed (bleached from red seaweed?). Color pinkish-reddish.
3:44 Open water
4:00 Fish grazing on vertical pole covered with organisms. Small fish laterally flattened. Condensation in camera chamber a problem.
5:35 A clump of green-colored seaweed to left (Codium fragile). Bottom is soft. Red encrusting stuff on Codium (Star tunicate or Botrylloides schlosseri?).
6:17 Ficopomatus reef red stuff = Star tunicate; beige brushy stuff.
9:13 Long stretch of open water with weed-covered bottom.
11:05 Shift to dense mussels encrusted with white/beige stuff on upper surface usually; orange tunicate (Star?)
Sunday, August 12th, we had a great little expedition. Lake Merritt Observatory's first. Katie Noonan organized the day bringing out her usual array of sampling equipment. Adrian Cotter set up the OpenROV (named RV Grebe, RV for research vessel :-) and after a little bit of worry and a couple of restarts, had it in the water and exploring for the next hour and a half.
Raven, Davonte, and Angela were out to help: having a go at the ROV controls, helping with various sampling efforts, checking out what the ROV dragged up (at one point the tether brought up some seaweed, which we scooped up and poked around to see what might be living there), and Raven filled out our Lake Merritt Observatory whiteboard for the day (see photos).
We had some learnings:
- an umbrella or some sort of sun blocker would come in handy
- turn off the HUD when you record!
We still have to take some time to go through the video and catalog all that's on there: anemones, mussels, various little fish, seaweeds, tunicates, a crab hanging from the pylon, and more!
We're looking forward to exploring some different parts of the lake, and figuring out how best to use the ROV.
Students who participated in the OpenROV program will collaborate to design an expedition. Stay tuned.
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