NOAA Teacher at Sea
Lisa Werner
Aboard NOAA Ship Bell M. Shimada
August 29-September 13, 2024
Mission: EXPRESS Project
Geographic Area of Cruise: Pacific Coast, near Northern California
Date: September 6, 2024
Weather Data from the Bridge (Mendocino Ridge Essential Fish Habitat Conservation Area):
Latitude: 40º18.178’ N
Longitude: 124º48.470’W
Wind Speed: 5.87 knots
Air Temperature: 14.3ºC/57.74ºF
Conditions: Foggy
Science and Technology Log
There are many methods of studying the ecosystem of the ocean on the mission that I am on, and another method we are utilizing is that of Environmental DNA (referred to as eDNA). Every living organism in the ocean leaves behind traces of its existence. Much like humans shed skin cells and hair, and cats and dogs shed fur, ocean organisms leave behind skin, scales, and waste products. These artifacts contain DNA, and can last in the water for anywhere from 7 to 21 days. Scientists have ways of collecting eDNA using the CTD (Conductivity, Temperature, and Depth) rosette.
A CTD rosette is a device that is routinely lowered off of the ship to monitor the temperature and conductivity of the water at measured depths in the water column. NOAA Ship Bell M. Shimada’s rosette has 12 containers, called Niskin bottles, that are opened before deployment, and then triggered at different depths one at a time as the rosette ascends, trapping the water from that depth inside. Separate from these collections, sensors analyze the temperature, salinity (salt levels), pressure, dissolved oxygen, turbidity (cloudiness), and other useful information. The data collected from the CTD shows up instantaneously on a computer screen aboard the ship.
To collect eDNA, the scientists look at where the biggest temperature changes happen (called the thermocline). Once the CTD is back aboard the ship’s deck, the scientists pump the water collected in the Niskin bottles triggered at the depths surrounding the thermocline through a filter. The eDNA material is collected and strained into this filter, where it is preserved to be sent to a lab for further analysis. Once the eDNA gets to the lab, scientists look at the DNA “fingerprints” left behind by organisms and match them to a database of known DNA. The scientists then have knowledge of what organisms were present in that location in the ocean at the depths those samples were collected from.
This goes hand in hand with the work I blogged about last on the MultiNet. The identification of the plankton that Jenn is doing is part of the work that goes into the database helping scientists identify DNA from the eDNA samples.
Personal Log
I’ve gotten a lot of questions about what the food is like on the ship, and anyone who knows me knows that food is a big part of my life! The ship’s cook, Ronnie, is amazing. He cooks the food from scratch, and it is not uncommon to see meatballs being rolled out for the next meal, or other prep taking place. The meals are served buffet-style, and there is no shortage of food. Even the pickiest eater would be happily satisfied here.
For Labor Day, we got to have a cookout on the ship’s back deck. It was quite the feast, featuring all of the grilled meat and fixings you could want.
Also, if at any meal you ‘forget’ to take dessert, Ed, the steward, will remind you. He’s always looking out for your best interest! He also always has the best jazz music playing in the kitchen.
Finally, I have to take a minute to wish my Dad a happy birthday! I had some cake to celebrate you today, Dad!!!
Music Connections
In looking at how the eDNA analysis works, I’m going to compare it to listening to an audio recording of a high school band. When a person listens to a recording of the band, they can tell what instruments are represented in the recording. For example, you may notice that there are flutes, oboes, clarinets, and saxophones, but perhaps the band is missing a bassoonist. If the group does a really good job of section playing, you would have a very tough time picking out HOW MANY flutists are in the recording. You may be able to hear that there are a lot of them, based on the depth of sound you hear throughout the dynamics being played, but you could not say with any confidence whether there are 7, 8, or 9 flutists. You also would not know whether one of the high school students was absent that day, or whether a guest was playing on the recording as well. The process of eDNA analysis is the same way – scientists can tell what was present in that one snapshot of time, based on the DNA present in the sample. They cannot tell you how many of each organism is present, or whether those organisms live there or were merely just migrating through the area.
For today’s audio clip, I recorded the ship’s horn being blown as a result of the reduced visibility from the fog. I learned that there are several different patterns for the horn to blow, and the example I have for you here is the long fog horn blast followed by two short blasts, signaling that we are unable to change course (in this case, due to the fact that we are acoustically tethered to the AUV that was in the water at the time)
Student Questions
Students asked me to be on the lookout for dolphins. On our third day at sea, we saw a whole pod of dolphins right next to the ship! Here’s a very short video to watch them all, and I am not zoomed in at all with my phone!