NOAA Teacher at Sea
Aboard NOAA Ship Oregon II
June 22 – July 3, 2012
Mission: Groundfish Survey
Geographical area of cruise: Gulf of Mexico
Date: July 1, 2012
Ship Data from the Bridge
Speed: 10 knots
Wind Speed: 9.65
Wind Direction: S/SE
Surface Water Salinity:35.31
Air Temperature: 28.2 C
Relative Humidity: 76%
Barometric Pressure: 1017 mb
Water Depth: 57.54 m
Science and Technology Log
Here I’m filling up the BOD jar with our salt water samples from the CTD cast.
Reminiscent of my days in high school chemistry, today I had the opportunity to work with our Chief Scientist, Brittany, on completing the daily titration. If you remember, getting readings on the dissolved oxygen in the water is an important part of this survey as we locate any hypoxic (less than 2 mg of oxygen per liter of water) zones or anoxic (no oxygen) zones. This is done with a computerized device on the CTD, but we want to make sure that our readings are accurate. Because “chemistry never lies”, this is how we ensure our readings are accurate.
With our CTD, we have the ability to collect water samples at various depths. We do not collect water samples at every CTD, but rather one or two a day during the daytime hours. We collect water from the bottom to see if there is any expansion of hypoxia.
Using the Orion dissolved oxygen meter to measure the amount of dissolved oxygen in our sample.
When the CTD comes back up, we use an Orion dissolved oxygen meter, which is a handheld device, to get a dissolved oxygen reading from our samples. We put the probe on the end of the meter gently into the containers of water on the CTD to get our reading. We will use this number in conjunction with the information sent from the CTD to our dry lab to check against our titration results.
Once we have the reading with the probe, we are ready to take some samples for our titration. We then take the water samples in the cylinders, rinse out our 300 mL BOD (biological oxygen demand) glass bottles a few times with that water, and then fill the botttles up with the sea water from the bottom. These samples are brought back to our Chem Lab (short for chemistry, as I’m sure you figured out) where we will test the amount of dissolved oxygen.
Adding the manganese sulfate to our sample.
This is after I’ve added the manganese sulfate and iodide. Now we have to wait for it to settle.
We are using the Winkler method to find the amount of dissolved oxygen in our water samples. The first step in this process is to put 2mL of manganese sulfate into the bottle. After that, we also add 2 mL of azide- iodide. With those 2 chemicals added, we carefully replace the stopper and give the bottle a good shake. We then can wait about 10-15 minutes for the chemicals to settle at the bottom. Pipettes are used to add the liquids and allow us to be very precise in our measurements.
Here is our sample after it has settled.
After the particles have settled at the bottom, we add 2 mL of sulfuric acid (which can be a dangerous chemical if used inappropriately), replace the stopper, and shake the bottle again gently. The sulfuric acid “fixes” the solution. Finally we add 2 mL of starch to the solution, which is a blue indicator when we put it in but turns the solution a burnt orange color. Now we are ready to titrate!
Our sample solution being poured into the beaker, ready for the titration. Inside the beaker is a magnetic stirrer.
Now you can see the solution is clear in color, meaning our titration is finished. We are ready to determine the amount of dissolved oxygen.
Prepared beforehand was a burette filled with phenylarsine oxide, what we use to drip into the sample. We pour the sample into a beaker and place it on a magnetic plate. We’ve placed a magnetic stirrer in the beaker so it gently stirs the solution while we are titrating. We let the phenylarsine oxide slowly drip into the sample until it turns clear. When it does this, we note the amount of phenylarsine oxide that we put in the sample (which is equivalent to the amount of oxygen in the water), and the number should match (or be very close) to the reading of dissolved oxygen that we received from the CTD and the Orion dissolved oxygen meter.
This process is quite simple yet yields important results and is just one of the ways scientists verify their data.
One other interesting thing happened the other night on one of our shifts. We had brought in a bongo tow and were looking into the codends to see what we got. When Alex began rinsing the sample with some salt water, the whole codend began to illuminate. Why did it illuminate? Bioluminescence. Bioluminescence is essentially a chemical reaction that produces light. Many marine critters can produce bioluminescence, as seen below.
Bioluminescence in our bongo tow.
One of the things I’ve probably enjoyed the most about my trip so far are the relationships I’ve formed with the people on board. As a teacher, one of my top priorities is to build and maintain relationships with my students, both past and present. That became a bit more of a challenge to me this past year as I took on a new position and began teaching 600 students rather than the 30 I was used to.
Our watch leader, Alonzo, waiting to weigh our next catch.
I’ve come to love working with the scientists on the night watch, as each of them brings something to the table. Our watch leader, Alonzo, has a wealth of knowledge that he gladly shares with each of us, pushing us to learn more and find the answer for ourselves. I’ve improved immensely on identifying the different fish, crabs and shrimp we find (thanks to Lindsey, who is my partner in crime for making up silly ways to remember these crazy Latin names for all our species). Where I came in knowing names of very few if any types of Gulf critters, I can now confidently identify 15-20 different species. I’m learning more about how to look for the subtle differences between different species, and Alonzo has been able to sit back and be that “guide on the side” while we work and input all of our data. His patient demeanor has allowed all of us to become more self-sufficient and to become more confident in the knowledge we have gained thus far on this trip.
Alex with a sharksucker
Alex, another one of the scientists on my watch, shows an endless enthusiasm for marine science. He shares in my excitement when a trawl comes up, and the both of us rush out there to watch the net come up, often guessing how big we think the catch is going to be. Will it fill one basket? Two? Six? It’s even more exciting when we get inside and lay it out on the conveyor belt and can really examine everything carefully. His wish finally came true today as we are now in the eastern part of the Gulf. Alex is studying lionfish (Pterois volitans) for his research, and of course has been hoping to catch some. Today we caught 4, along with a multitude of other unique critters that we have not seen yet. Alex’s enthusiasm and passion for science is something I hope my students can find, whether it be in marine science, biology, or meteorology- whatever it is they love is what I hope they pursue.
Lindsey and Alex, getting ready to work.
Lindsey and Renee are both graduate students. Rene wanted to gain some experience and came on the ship as a volunteer. What a better way to get a hands-on experience! Lindsey has joined us on this cruise because she is doing research on Sargassum communities. She has been able to collect quite a few Sargassum samples to include in her research for her thesis. Lindsey, like Alex, is very passionate and excited about what she does. I’ve never seen someone more excited to pull up a net full of Sargassum (which I’m sure you remember is a type of seaweed) in order to sift through and find critters. She has a great eye, though, because she always manages to find even the tiniest of critters in her samples. Just yesterday she found a baby seahorse that couldn’t have been more than a few millimeters long! Outside I hear her giggle with glee- I know this is because she has found a Sargassum fish, which is her all-time favorite.
Our night shift deck crew- Tim, Chuck and Reggie
Our night watch would not be complete without the deck crew, Tim, Reggie and Chuck, who are responsible for helping us lower the CTD, Neuston and bongo tows, and for the trawl net. Our work could not be done without them.
William, one of our engineers, took me down into the engine room the other day. First impressions- it was hot and noisy! It was neat to see all the different machines. The ship makes its own water using a reverse osmosis system, which takes water from the ocean and converts it into drinking water for us (this water is also used for showers and sinks on board). One interesting note is that the toilets actually use salt water rather than fresh water so that we conserve our fresh water.
Our reverse osmosis systems.
I cannot believe how fast this leg has gone and that we only have a few more shifts to go before we return to the Oregon II’s home port of Pascagoula. As we’ve moved into the eastern waters of the Gulf, we have seen a lot of different types of critters. On average, our most recent trawls have been much more brightly colored. We are near some coral reefs too- in our trawls we have pulled up a bit of coral and sponge. The markings on some of the fish are very intriguing, and even fish we’ve seen before seem to be just a little brighter in color out here.
Due to the fact that we are finding very different critters, my list of favorites for today has greatly increased! Here are just a few:
The mouth of a scorpion fish. We’ve caught a bunch of these since we hit the eastern Gulf.
A baby seahorse we pulled out of our Neuston tow. He was hiding in the Sargassum.
One of our biggest red snappers.
This is another type of bashful crab, also known as the flame-streaked box crab (Calappa flammea).
This octopus sure liked my hard hat!