NOAA Teacher at Sea
Aboard NOAA Ship Oregon II
July 10 – 20, 2017
Mission: Groundfish Survey
Geographic Area of Cruise: Gulf of Mexico
Date: July 12, 2017
Weather Data from the Bridge
We’re traveling through some mild rainstorms. Nothing extreme, but we do feel a little more side to side rocking motion in the boat (which makes me feel sleepy!)
Latitude: 29 degrees, 56.2 minutes North
Longitude: 86 degrees, 20.6 minutes West
Air temp: 24.7 degrees Celsius
Water temp: 30.1 degrees Celsius
Wind direction: light and variable
Wind speed: light and variable
Wave height: 1 foot (about 0.3 meters)
Sky: overcast with light rain
Science and Technology Log
Today I completed my first shift on the science team and we surveyed 3 complete stations. At each station, we carried out a multi-step protocol (or procedure). Here are the steps:
Before we begin fishing, the ship conducts a transect (or cross-section) of the survey area, using multiple pieces of equipment to observe the ocean floor. This tells us if it is safe (for both ship operations and for fragile coral that may exist) to trawl here. If a coral reef or other large obstacle was present, we would see significant variation in the depth of the ocean floor. This “depth contour output” graph shows the data we collected at one station. How deep is the water at this station? Is it safe to trawl here?
We also use a collection of instruments called a “CTD” to collect information about the chemistry of water itself at different depths. This information is called the water’s “profile.” For fisheries studies, we are most interested in the amount of dissolved oxygen and the temperature at different depths. Why might this information be relevant for understanding the health of fish populations?
We also measure the water color using the Forel-Ule color scale by matching it to the samples shown in this photo. This gives scientists an indication of the amount of particulates, chlorophyll, and nutrients are in the water.
Once we determine it is safe to trawl, the ship returns to the starting location. We will trawl along the same path that we observed. Here’s the trawl net before it is lowered into the water. It will be pulled just along the bottom of the survey area, using tickler chains to agitate the ocean floor for benthic organisms for 30 minutes, and collecting whatever crosses its path!
Once the trawl is finished, the deck crew uses a large crane to pull the trawl on board. We all help to empty the net and place everything into baskets. Most of what we catch are biological organisms, but small amounts of non-living material (like shells, dead coral, and even trash) come up as well.
We then bring the baskets into the wet lab.
We dump the baskets into a long metal trough that has a conveyor belt at the bottom.
Next we sort the catch. Each species gets its own basket and we count the number of individuals for each species.
Then, it’s time for the tough part (for me at least) – every organism has to be identified by its scientific name. That’s a lot of Latin! Fortunately, Andre and the senior scientists are very patient and happy to help those of us who are new. It’s amazing how many species these experienced scientists recognize off the top of their heads.
We also have many field guides, which are books containing photos and descriptions of species, to help us.
We are interested in how much of each species are present, so we record both the total number of individuals and total mass of each species.
We also measure the length and mass of a sample of individuals. A handy device called a Limnoterra Electronic Measuring Board makes this process easy. We place the mouth of the fish on one end of this board and then touch its tail fin with a pen-like magnetic wand. The board then automatically sends the fish’s length to the computer to be recorded. We use an electronic balance that is also connected to the computer to measure and record mass.
All of the information is recorded in a database, using software called FSCS (pronounced “fiscus”).
Many of the specimens we collect are saved for use in further research on land. Scientists at NOAA and other research institutions can request that we “bag and tag” species that they want. Those samples are then frozen and given to the scientists when we return to shore.
Any organisms or other material that remains is returned to the sea, where it can be eaten or continue its natural cycle through the ecosystem. The conveyor belt, conveniently, travels to a chute that empties back into the ocean. Now all that’s left is to clean the lab and wait for the process to begin again at the next station!
Our goal is to complete this process 48 times, at the 48 remaining stations, while at sea. 3 down, 45 to go!
This work has real highs and lows for me, personally. There are dramatic, hold your breath, moments like when equipment is lifted off the deck with cranes and lowered into the water. There is the excitement of anticipating what data or species we will find. My favorite moment is when we dump the buckets and all of the different species become visible. I’m amazed at the diversity and beauty of organisms that we continue to see. It reminds me of all of the stereotypical “under the sea” images you might see in a Disney movie.
The more challenging part is the pace of the work. Sometimes there are many different things going on, so it’s easy to keep busy and focus on learning new things, so time passes quickly. Other times, though, things get repetitive. For example, once we start entering all of the data about the individual fish, one person calls out the length and mass of a fish, while the other enters it into the computer – over and over until we’ve worked through all of the fish.
Sometimes, the work even stops altogether, especially when the weather interferes. There have been mild rainstorms coming and going continually. It is not safe to have people on deck to deploy the CTD and trawling equipment when there is lightning in the area, so there is nothing for the science team to do but wait during these times.
Because the pace of the work is constantly changing, it’s difficult to get into a groove, so I found myself getting really tired at the end of the shift. However, an important part of collecting data out in the field is being flexible and adapting to the surroundings. There is a lot to accomplish in a limited amount of time so I keep reminding myself to focus on the work and do my best to contribute!
Did You Know?
When working at sea, scientists must use special balances that are able to compensate for the movement of the ship in order to get accurate measurements of mass.
To ensure that we are accurately identifying species, we save 1 individual from each species caught at a randomly selected station. We will freeze those individuals and take them back to NOAA’s lab in Pascagoula, where other scientists will confirm that we identified the species correctly!
Questions to Consider:
Review: Look at the “depth contour output” graph above: How deep is the water at this station? Is it safe to trawl here?
Research: What does “CTD” stand for?
Research: For fisheries studies, we are most interested in the amount of dissolved oxygen and the temperature at different depths. Why might this information be relevant for understanding the health of fish populations?
Reflect: Why might scientists decide to use three different pieces of equipment to collect the same data about the ocean floor? And, why might they have several different scientists independently identify the species name of the same individuals?