Author Archives: Yuen Azu, 2022 AAUS Somers

The Tahoe Experience

My phone camera doesn’t quite capture the view I take in with my own eyes– the glass-like aqua blue water, the sweeping mountains lined with pine trees trailing all the way down to shore, the boulders bigger than cars that rest partially submerged– but looking back at my photos, I’m reminded of the fond memories I made here. The past month of my life revolving around Lake Tahoe was truly something spectacular, and I know I’ll be back someday to enjoy the beautiful scenery once again. 

Sand Harbor, Lake Tahoe. Photo credit: Brant Allen

The second leg of my internship was based at the UC Davis Tahoe Environmental Research Center (TERC), located in Incline Village, Nevada. I arrived a week before field work began but jumped right into the action as I was settling in. There was quite a bit of preparation to be done for the underwater surveys that I would be helping with. The Asian clam, a non-native species to Lake Tahoe, was first reported by TERC researchers in the south-eastern shore of the lake back in 2002, likely from an accidental introduction from a visiting boat. Since then, they have been spotted in other areas of the lake, including Sand Harbor. The main concern for their appearance in the lake is the algae that follows them. In densely populated areas of clams, this green algae builds up along the bottom due to the nutrients released by these shellfish. Large plumes grow, cloud up the water, and eventually end up washing up to shore. Lake Tahoe is known for its picturesque, clear blue water and scenic shorelines, but the Asian clam may soon alter these idyllic features if left unchecked. And this was why I was jumping in. 

Invasive Asian clams (Corbicula fluminea) blanketed by green algae. Photo credit: Brandon Berry

My task was to help capture underwater data with the TERC Dive Field Team as part of a multi-year clam-population study at Sand Harbor, located on the eastern shore of the lake. One of the team members, Erik Young, was a fellow AAUS scientific diving trainee with me at Bodega Marine Lab (BML) earlier this summer. The other three members– Katie Senft, Brandon Berry, and Brant Allen– were seasoned clam-collectors and showed me and Erik the ropes for the study. For two weeks, we got up early to hop on the R/V Bob Richards at the Tahoe City Marina and travel across the lake. Some of our survey sites were shallow enough to snorkel along, but the deepest areas we surveyed were at about 35 feet. We slipped into our wetsuits, staged our gear, and stepped off the boat with our minnow traps, which we used to scoop up the sand and filter out for clams. 

My mornings began at the field station in Tahoe City. Photo credit: Yuen Azu

Katie Senft (left) and me (right) collecting clams with our minnow traps. Photo credit: Brandon Berry

Holding up a bag of clams. Photo credit: Katie Senft

The first week was the perfect temperature for our dives. It was hot enough at the surface for us to stay comfortably warm underwater for over half an hour. However, a fire was burning southwest of Lake Tahoe and was carrying over smoke and colder temperatures. On top of this, I had unfortunately caught swimmer’s ear and had to take a couple of days off to heal up. It was agonizing to miss out, but I was able to rejoin the group for the last few days and finish our mission. 

A smoked-out view of the lake from the Mosquito Fire. Photo credit: Yuen Azu

My research dives at the lake had concluded, but the clam survey was far from over. It was now time to count and measure every single clam that we had collected. Dressed in a lab coat with calipers in hand, I went through jars and jars of our preserved bivalves and took careful notes of their measurements. The raw data sheets had to be transferred to the computer, so when I got tired of measuring I switched over to data entry. With the help of the others, we were able to get through most of the samples in four days, before my time at TERC was up.

Measuring clams back at the TERC laboratory. Photo credit: Yuen Azu

The last official week of my internship was spent learning how to dive with a drysuit. Emerald Bay, the southern region of Lake Tahoe, was my training ground. The State Parks Dive Team had generously included UC Davis divers for their refresher course on underwater surveying, and Jason Herum, my instructor and main BML contact, was in charge of teaching the Altitude Diving course. Over three days, we learned about the precautions needed to dive over 1000 feet above sea level and I went on six drysuit dives. 

Donned in a drysuit for the first time. Photo credit: Sydney Salley

Drysuits, as opposed to wetsuits, are water-proof and require air from your tank to be added as you dive. With the added complications of an extra air space, you’ll need to be trained and certified to use one. It was strange to have to return to buoyancy-control basics, a skill that had become natural to me over the years. As I waded into the water in my hot-pink rental for the first time, I pressed the inflator valve on my chest to add some air inside the water-proof suit. The deflator valve was located just below my left shoulder, and I had opened it almost all the way to allow air to vent out whenever I lifted my arm. Jason and I swam not too far from shore and descended to the sandy bottom at about 10 feet. I practiced adding enough air to my suit to hover above the bottom, then letting out the air so we could kneel. I lifted my left elbow up gently and a string of bubbles escaped out of the deflator valve – Jason called the motion ‘the chicken-wing’. Next, we practiced a technique to right yourself if the air moves to your feet and causes you to go upside-down. After moving into a head-first position, Jason tucked in his upper-half and rolled forward into an upright position. I copied, with mild success. After practicing the new drills in the shallows for a while, we headed down the steep slope further off-shore so I could work on adjusting the air in my suit as we descended. It was the first time I felt the thermocline– a depth in the water column that was much colder than above– while diving in Tahoe. 

For the next few days, I dove alongside my friends and instructors from BML, exploring several old wrecks and continuing to hone my buoyancy. The morning of our last dive, Jason gave me and the other two drysuit trainees a new task: we were to lead the dives as a trio. Up until that point, we had been following Jason underwater. We floated at the surface for a few minutes to hash out a plan and then descended. Once we were on our way however, we realized our discussion was not detailed enough. We hadn’t picked out an actual lead among the three of us, nor had we decided how long we were staying in the shallower area to review our drysuit skills before descending further for the rest of our dive. With the limitations of hand signals to communicate, we struggled to coordinate. Immediately after surfacing we debriefed on the issues we had. Our second and final dive that day was to redeem ourselves, and this time, we were much more explicit and careful with our dive plan. It was a serene dive as we descended upon a sunken boat not too far from shore. We had all vastly improved on our buoyancy control and seamlessly executed our plan. As I surfaced this time, I was elated that it went so well, but it was dawning on me that it was my last internship dive. My final day in Lake Tahoe had proved to be an important lesson on dive planning, and so I finished my internship with a drysuit certificate and a healthy dose of humility. 

My fellow dive-mates Erik Young (left) and Sydney Salley (middle) getting into our drysuits. Photo credit: John Harreld

Emerald Bay dive site. Photo credit: Yuen Azu

Although my time as the OWUSS/AAUS Dr. Lee. H. Somers Intern has come to an end, it has opened up a world of opportunities that I am excited to explore next. With just a semester left of my undergraduate education, I am hoping to find a research position that involves lots of diving within the next year. From there, I’ll gain more experience to prepare me for graduate school and a career in marine biological research. There were so many people that I met these past few months that impacted my experience, not just those explicitly mentioned in my blog. To all those whom I learned from, learned with, and/or shared any of the incredible experiences I had, I am deeply grateful that our paths crossed. 

I also cannot go without saying thank you to my wonderful family on the west coast who all made me feel right at home, and to my friends and immediate family for their support. My deepest gratitude goes towards The AAUS Foundation, which made this internship possible in conjunction with the Our World Underwater Scholarship Society. Finally, I have to thank my OWUSS family and my hosts at UC Davis for making sure my internship was a blast! 


Mastering the Art of Working Under Pressure… Literally

Hi! My name is Yuen Azu, and I am the 2022 Our World Underwater Scholarship Society (OWUSS) / American Academy of Underwater Sciences (AAUS) Dr. Lee H. Somers Scientific Diving Intern, hosted by the University of California, Davis Bodega Marine Laboratory. I’m an undergraduate at Amherst College working towards a Biology degree, and I got an amazing opportunity this year to learn how to dive for research purposes.

My story begins in mid-July. It was a foggy, cool morning when I arrived at the Bodega Marine Laboratory. Surrounded in state protected land, the laboratory entrance is landmarked by a solid group of trees fortifying the gate. I eeked at 15 miles per hour along the last stretch of road after punching in the gate code, keenly aware of my speed after reading the warning signs for wildlife crossings. Horseshoe cove was blanketed in a gradient of whiteness until the undulating water disappeared just beyond the headlands. I was tempted to step out of my car and walk along the shore for a quick scenic stop, but the entrance was closed off with NO ENTRY PERMITTED signs.

Entrance to the Bodega Marine Laboratory in Bodega Bay, California

I stepped out and pulled on a sweater. I had been warned about the mild temperatures of the coast but had naively thought that I could handle it Michigan-style. Still, it was the middle of summer and my brain was wired for heat at this time of year. Jason Herum, the Dive Safety Officer (DSO) for UC Davis and my day-to-day contact at the lab, was here to give me a private tour of the facility. He greeted me warmly outside, and we headed towards the main building. We had long phone conversations about the logistics of my internship over the past several months, and it was great to finally put a face to his voice. At a relaxed pace we made our way to the different wings of the building and walked over to other areas that I would be spending quite some time at, like the dive safety classroom, the dive locker, and the tank filling station. We also made a stop at the north-western edge of the property, a concrete and wood structure designated as the Diver Training Facility. Jason swung the heavy wooden door open and a blue, crystal-clear pool appeared on the other side. If it hadn’t been in the low 60s, I would have dipped my toes in the water without hesitation. We continued the outdoor tour to the edge of Horseshoe Cove, and Jason explained that typically access was restricted due to ongoing research, live feed cameras, and marine mammal pupping seasons. Hence the NO ENTRY PERMITTED signs.

Diver training facility at Bodega Marine Laboratory

I had a couple of days to settle in before the first half of the Research Dive Techniques course would begin. I spent that time sightseeing the Bodega Head, mentally and literally prepping for an intensive week, and catching the 2022 Australasian Scholar, Millie Mannering, right before she headed out to her next adventure. Helping her out was 2019 DAN Intern Abbey Dias, who also happened to work at BML. It was only for a few hours that day, but I was excited to see two familiar faces before my internship officially began.

Sunday rolled around and marked the beginning of a whirlwind week full of lectures, pool time, and mild sunburns. I met the other five students and learned their stories leading them to this course, each at a different point in their lives–either in graduate school, in between school, or working. I also met the other instructors alongside Jason: Shelby Kawana, the Assistant Boating and Diving Safety Officer, John Harreld, the Volunteer Instructor and co-founder of the Sonoma Coast Historical and Undersea Nautical Research Society (SCHUNRS), and Brian Bennett, the DSO at both San Francisco State University and Sonoma State University.

A snapshot of a classroom lecture for the Research Diving Techniques Course (Photo credit: Jason Herum)

With a 2:3 instructor-to-student ratio, we had a highly individualized learning experience. It had been months since I last took a breath while underwater and even longer since I dove in 50-degree water, so I needed a few moments for my body to adjust to the coldness seeping into my wetsuit. I wasn’t sure if I could get used to all of the restrictive layers of neoprene, especially with such thick gloves that made simple tasks cumbersome, but by the end of the week, I became much more confident in myself as a diver. My basic skills improved significantly, and I now feel a greater sense of security and assurance from having gone through rescue drills and learning to provide emergency care. We spent hours practicing CPR and using AEDs on dummies, setting up and breaking down oxygen units, and performing neurological assessments. In the water, we simulated beach and boat rescues, out-of-air scenarios, and my favorite– the ditch and don. In this exercise, we had to remove all of our gear (except our weight belts) at the bottom of the pool, turn off our tank, ascend to the surface, dive back down, turn on our tank, and put everything back on. If that sounds crazy to you, trust me, I was thinking the same thing when it was my turn. The ditching was relatively simple, but the donning was quite a struggle. I felt like I barely made it swimming back down to the 14-foot bottom without either my fins to propel me or my mask to help me navigate the otherwise blurry world. By the time I got my regulator in my mouth and opened up my tank, I was gasping. Conquering that challenge was the highlight of my day, maybe my week. On top of those emergency skills, we also hopped in the rarely-accessed Horseshoe cove to practice freediving and navigation. I had quite a lot of fun with both, but the navigation in particular was another confidence-boosting moment as my buddy and I landed fairly close to our target location in murky, surging waters. 

An injured diver scenario with us students in action (Photo credit: Jason Herum)

Standing in front of Horseshoe Cove and ready to freedive! (Photo credit: Sarah King)

The last two days of the session were dedicated to biological surveys and marine archaeology fundamentals. We simulated invertebrate transects, practiced sketching quadrats, used lift bags and redundant air sources, and performed trilateration. In addition to all of this, I was trained in using enhanced air nitrox (also called simply ‘nitrox’ or abbreviated as ‘EAN’) in which I breathe off a tank that has a higher percentage of oxygen. By the end of the first week of my internship, I obtained DAN DFA Pro certification.

Conducting a trilateration of a sunken canoe in the Dive Training Facility with my dive buddy (left) (Photo credit: Shelby Kawana)

A group shot on the last pool session at the Diver Training Facility (Photo credit: Shelby Kawana)

During the next few weeks of my internship, I joined dive projects, helped out at the tank-filling station, and shadowed a couple of labs at BML. My first dive was a marine archaeology survey in search of an anchor in a cove off the Pacific coast, and my second dive was to help retrieve, clean, upload data from, and re-attach scientific equipment at the NOAA field station located in the San Francisco Bay (with a great view of the Golden Gate Bridge). My third dive was in the cove right off BML, in which I video-recorded two other divers repairing underwater equipment. I also got to join a boat operation to collect water quality data in Tomales Bay, and on a separate occasion I got to dive there for some underwater instrument maintenance. Back at the lab, I got to learn the basics of air compressors and filling tanks with both air and Nitrox, and was also introduced to white abalone restoration research. 

On a mission with John Harreld to GPS-tag an anchor (Photo credit: Shelby Kawana)

Cleaning a CTD instrument with a view of the Golden Gate Bridge in the distance (Photo credit: Gregg Holzer)

In mid-August, we had the second half of the research diving course. We camped along the Sonoma coast and spent five days refining the skills we learned in the pool with a greater focus on scientific diving. We performed two types of marine archaeology search techniques and conducted invertebrate transects. Our final dive was geared towards exploring a shipwreck off Fort Ross, but the visibility was so bad that we instead turned the dive into a navigation exercise back to our entry point. By completing the course, I not only obtained AAUS Scientific Diving certification, but I left with NAUI Rescue Diving and Nitrox certification as well. It only hit me after sitting down and reviewing our course schedule that I had learned so much since the first day. Without the amazingly patient, helpful, and encouraging instructors, volunteers, fellow students, and other BML staff, I wouldn’t have gotten this far. 

Fully geared up and entering the water at Fort Ross (Photo credit: Sarah King)

Off to do invertebrate transects with my dive buddy Will Johnson (Photo credit: Jason Herum)

Holding up my certificate of completion for the UC Davis Research Techniques course (Photo credit: Isabelle Neylan)

For the latter half of my internship, I’ll be relocating to Lake Tahoe for the entirety of September to conduct invasive species surveys alongside the UC Davis Dive Team and work with the California State Parks Dive Team on a marine archaeology project. I’ll miss all of the little charms of Bodega Bay and my adventures around this area, but I’m stoked to start the next leg of my journey. What better place than a picturesque lake to spend a month honing my scientific diving skills!