Anna Levy: What Tummies Tell Us, July 15, 2017

NOAA Teacher at Sea

Anna Levy

Aboard NOAA Ship Oregon II

July 10 – 20, 2017


Mission: Groundfish Survey

Geographic Area of Cruise: Gulf of Mexico

Date: July 15, 2017


Weather Data from the Bridge

Scattered, mild storms continue, causing some delays in our fishing. However, they do lead to beautiful sunsets!

Beautiful Gulf of Mexico sunset

Latitude: 29 18.790 N

Longitude: 84 52.358 W


Air temp: 28.7 C

Water temp: 29.7 C

Wind direction: light and variable

Wind speed: light and variable

Wave height: 0.3 meter

Sky: 80% cloud cover, no rain


Science and Technology Log

TAS Anna Levy removes the stomach of a red snapper.

Data about the number and size of individual organisms can tell us a lot about the health of an overall population of a species. However, it doesn’t tell us much about the role that species plays in its community. If we want to understand that better, we need to know more about how it fits into its food web – what it eats and what eats it. If you were trying to collect information about what a fish eats, where would you look first? Its stomach!

So, after we measure certain species, we dissect them and remove their stomachs. We place each stomach in its own tiny bag, with a bar code that identifies which individual fish it belonged to. Back at a lab on land, scientists will carefully examine the contents of the stomachs to better understand what each species was eating.

The bar codes that we use to label specimens.


This map shows the native range of lionfish. Credit:

For example, one of the fish currently under investigation in the Gulf of Mexico is the lionfish. This is an invasive species, which means that it is not native to the area. Its natural habitat is in parts of southern Pacific and Indian oceans, but it was first spotted in the Atlantic, off the coast of North Carolina, in 2002. Lionfish were most likely introduced to this area by humans, when they no longer wanted the fish as an aquarium pet. By 2010, its range had expanded to include the Gulf. And, with no natural predators in this area and rapid rates of reproduction, its numbers have increased exponentially.

Early dietary studies, which were focused on the lionfish in the Atlantic, show that the lionfish is a generalist. This means that, while it prefers to eat small reef fish, it is able to eat a wide variety of organisms including benthic invertebrates (like crabs) and other fish. This flexibility makes lionfish even more resilient and able to spread. These studies also found that lionfish stomachs were rarely empty, suggesting that they are highly successful predators, able to out-compete other top predators for food.

This has wildlife experts concerned about the impact lionfish will have on natural ecosystems. It is possible that lionfish will over-consume native species, causing native ecosystems to collapse. It is also possible that lionfish will out-compete and displace native, high level predators, like snapper and grouper. Scientists are working now to develop methods to try to manage this invasion.

Because ecosystems here are different from those in the Atlantic, scientists are now turning their attention to studying the lionfish in the Gulf of Mexico. The work that we did on the boat today should help them do just that!

To see the results of one such study, completed in 2014, see:

For more information and photos about the lionfish, please see:


Personal Log

Often times, we teachers struggle to convince our students that, while all of the modern technology we have is great, they also need to understand how to solve problems without relying on it. (Most of us have probably been on at least one side of the old, “no, you don’t need a calculator to multiply by 10!” argument at some point in life.)   Well, in the past couple of days, I’ve seen two great examples of this onboard the ship.

The first relates directly to our survey work. Our CTD, the equipment mentioned in last post, has two sensors that both detect how much dissolved oxygen is in the water. Having two instruments collecting the same information (sometimes called redundancy) is important, not only so that there is a back-up in case one breaks, but also so that we can tell if they are measuring accurately.

The two oxygen sensors have been reading differently – one was about 0.7 mg/L lower than the other. This is an indication that one needs to be calibrated – but which one? To find out, Alonzo Hamilton, one of the senior NOAA scientists, used a classical chemical analysis technique called titration.

This is the titration equipment found in the chemical lab on board the ship.

In a chemical titration, one substance is slowly added to another, while the scientist watches for a chemical reaction to occur. If you know how the two substances react, you can determine how much of the second substance is present, based on how much of the first was added to make the reaction happen.

Based on the results of his titration, Alonzo was able to determine which of the oxygen sensors was reading accurately. So, it definitely goes to show that there are important applications for that classic high school chemistry!

The binnacle that houses the ship’s magnetic compass.

The other example relates more to the ability to navigate the ship. NOAA Ship Oregon II is equipped with advanced electronic navigation software, Gyro compass, radar, and GPS systems. However, when I was exploring the top deck (flying bridge) of the ship, I came upon this strangely low-tech looking instrument. I asked ENS Chelsea Parrish, a NOAA Corps Officer and member of the wardroom, about it. She explained that it is called a “binnacle,” a safeguard that houses a magnetic compass! The magnetic compass is the same type of technology used by mariners back in the 1300’s. It is critical to have in case of a power outage or other disruption to the ship’s electronic navigation technology.



Did You Know?

While they typically live in cold waters, there is one pod of orca whales (aka killer whales) that resides, year-round, in the Gulf of Mexico. It’s rare to see them, but I’m keeping my eyes peeled!

Dolphins, on the other hand, seem to be everywhere out here. I’ve caught at least a glimpse of them every day so far. In fact, a group of them swam up to investigate our CTD today as it was being lowered into the water.


Questions to Consider:

Research: Some other famous invasive species in our oceans include the green crab (Carcinus maenas), killer algae (Caulerpa taxifolia), a jellyfish-like animal called a sea walnut (Mnemiopsis leidyi), a marine snail called rapa whelk (Rapana venosa), and the zebra mussel (Dreissena polymorpha). Where did each of these originate? How did they come to inhabit their invaded areas? What impact are they having?

Brainstorm: What measures could you imagine taking to manage some of these species?

Research: The specific type of titration used to determine the amount of dissolved oxygen in water is called the Winkler method. How does the Winkler method work?




Christina Peters: Update on Our Plankton Survey, July 16, 2013

NOAA Teacher at Sea
Chris Peters
Onboard NOAA Ship Oregon II
July 10 – 19, 2013

Weather and Location:
Time: 21:24 Greenwich Mean Time (5:24 p.m. in Rockville, MD)
Latitude:  29.1970
Longitude:  -85.9904
Speed (knots):  3.00
Water temperature:  28.10 degrees Celsius
Salinity (PSU = Practical Salinity Units): 34.07
Air temperature:  29.00 degrees Celsius
Relative Humidity:  68%
Wind Speed (knots):  17.15
Barometric Pressure (mb): 1018.96
Depth (m) = 187.2

As you can see if you have been following the Ship Tracker website, we have been making our way back towards Pascagoula.  We still have some stations to work, and won’t be reaching the dock until Friday morning, but we will continue to head in that direction.  The weather has gotten a bit windier, with much larger swells over the last couple of days.  This has made collecting the plankton even more interesting.  With the wind frequently above twenty knots, handling the equipment becomes much more dangerous.  Some procedures need to be changed a bit for the sake of safety.  Luckily, the deck crew, Tim, James, and Chuck, are on top of things.  They are pretty funny to work with, too!

Our deck crew
Our deck crew – James, Tim (chief boatswain), and Chuck

Science and Technology Log

Water Titrations to Check Cissolved Oxygen Levels

The plankton stations have continued, with the biggest changes being how much sargassum (seaweed) we have needed to rinse out and go through, and the different kinds of tiny animal life we have observed.  I mentioned in an earlier blog that the scientists must periodically do water titrations to verify that the readings taken from the CTD are correct and nothing is malfunctioning.  I had an opportunity to perform some real chemistry as Kim Johnson, the chief scientist, walked me through the water titration steps.

First we had to collect the water samples from the CTD.  Remember, we are testing the oxygen levels, so it is important to collect the water samples without allowing bubbles to form, which might add oxygen to the sample.  You would be surprised at how hard this is!  A flexible tube is attached to one of the three Niskin Bottles on the CTD tank, and before any water is put into the jars, all of the air bubbles in the tube must be squeezed out.  This is an art!  Then the water can be transferred to the jars through the tube, holding the end of the tube against the side of the beaker to avoid making bubbles.  The stoppers are then gently put into the glass jars, again to avoid the addition of oxygen to the samples.  It is important to keep the water samples from getting too hot if you are not going to do the titrations right away.  Can you think of why heat might create a problem when doing a titration?  Also, we test three samples.  Why do you think testing three beakers is important?

Now we are ready to start the mad chemist part!  The chemicals used, and their amounts, are very specific, and the directions are posted in the lab so that you can always check your memory.  First, two milliliters of manganous sulfate is added to each sample.  The stopper is replaced after adding each substance, and the jars are turned upside down and back several times to mix the solution. The second substance added is two milliliters of azide-iodide solution.  After the solution is gently mixed, the jars need to stand for ten to twenty minutes.  When you come back after twenty minutes, you will see that there is a cloudy substance in each jar.  This first part of the process causes the chemical bond between the hydrogen and the oxygen to break, and the oxygen forms new bonds with the added chemicals.

Adding chemicals
Using the pipettes to add the chemicals to the water
After initial chemicals are added
A cloudy substance forms after the manganous sulfate and azide-iodide are added and mixed.

At this point, the oxygen is fixed and we don’t need to worry about introducing more oxygen to the samples.  Next, we added two milliliters of sulfuric acid to each jar.  This must be done very carefully because sulfuric acid is very harmful.  However, once it is added, the sulfuric acid is neutralized and the solution in the sample jars is not harmful.  (Remember the acid/neutral/base tests we did in class with lemon juice, vinegar, and Alka Seltzer, using a pH scale?)

Sulfuric acid
The sulfuric acid changes the color, and after mixing, causes the cloudiness to disappear.

Now we have a yellowish liquid and I will be adding phenylarsine oxide, drop by drop. This is the titration part. When the color turns clear, we can look at how much phenylarsine oxide was needed and that will tell us how much dissolved oxygen was present in the sample. This new chemical will bond with the oxygen molecules and cause a color change. However, because the change from yellow is hard to see, I added one milliliter of a starch solution for the only purpose of turning the sample blue.  This way the color change back to clear is easier to see.

Starch is added
Notice the color change after the starch is added (the blue beaker).

The sample is poured into a wide-mouthed beaker and a magnetic stirrer is added to the beaker.  This is a small, magnetic bar that spins when it is on the metal stand.  Drops of the phenylarsine oxide are allowed to slowly drip from a burette into the sample.  A burette is a very tall, thin, glass pipe-like container that allows easy adjustment of the flow of liquid, and allows for easy reading of very small amounts.

Titration 1
The burette is allowing the phenylarsine oxide to mix with the water solution, one drop at a time.

Once the sample starts to lose its color, you know you are close. One or two more drops and you will shut the valve on the burette and read the amount that was mixed into the sample.

Titration 2
Notice the color change towards the end of the titration.
Titration complete
Once the color change is complete, the titration is finished, and the burette is read for the dissolved oxygen content.

My samples showed dissolved oxygen amounts of 6.4, 6.5, and 6.5 milligrams per liter.  The CTD showed dissolved oxygen of 6.4 mg/l.  Since our results were very close, we are confident that the CTD is working well.

Remember, levels below 2% are considered hypoxic.  6.4% is a very healthy dissolved oxygen reading. This is what we expect as we move further from developed land, but it is still reassuring to see the healthy levels.

Later I tried another titration without supervision and found consistent readings of 4.9 mg/ mg/l oxygen.  However the CTD reading was 4.35 mg/l.  I guess I need more practice! 

Buoy Rescue Mission

 Yesterday we had the opportunity to participate in a buoy rescue mission.  Another organization had deployed a wave buoy, or a wave runner, in the middle of the Gulf of Mexico that had been damaged, and was no longer able to give correct readings on things like current and wave height.  We were in the area, and agreed to retrieve the buoy.  As we got closer to the GPS signal, we spotted a large orange ball with an eight foot (about) antenna sticking out of it.  Oregon II’s small motor boat was launched and we set about collecting the buoy.

As we reached it, the deck crew and the CO noticed some things about the buoy that were inconsistent with the description.

Wrong buoy
Wrong buoy!

After making a telephone call, the CO told the crew to come back to the ship.  We had come across the wrong buoy!  Off we went in search of the correct one, which we found about half a mile away.  This one looked more like a surfboard and was fairly easy to get aboard the ship, using the crane.  That mission was accomplished, but we all marveled at the odds of finding two wave buoys within half a mile of each other in the middle of the Gulf of Mexico!

Weather buoy rescue
Using the crane to lift the wave runner onto the deck.
Chuck Godwin and Officer Matt , who helped rescue the wave runner
Chuck Godwin and LTJG Matthew Griffin, who helped rescue the wave runner
Both parts of the wave runner
The part of the wave runner that looks like a surfboard sits on top of the water and has solar panels. It is attached to the slatted part that acts as a glider, and uses wave energy as it rises and falls to propel the board through the water.

Personal Log

 A Week at Sea

While I am still enjoying the cruise and the work, I have had a few days of queasiness.  Taking the seasick medicine helps a lot, so I am sticking with that for a few days.  Nights have been fine, and the rocking of the ship really is like being rocked in a cradle.  I hope I’ll be able to sleep when I am in a stationary bed back home!

Being on a cruise on a small ship brings me back to my days of living in a college dormitory.  You are living in very close quarters, eating every meal together, spending large amounts of time together, and really getting to know the people who are on your watch.  I have had a great group to work with – people with a lot of knowledge, and great senses of humor!  Victoria, a college intern, has been a newbie with me.  We have learned a lot from the other scientists, Andre and Joey, on our watch, as well as from our chief scientist, Kimberley Johnson.  Tim, James, and Chuck are the deckhands on our watch, and they do most of the heavy work, like lifting the equipment and running the J frame, winches and cranes.  Sometimes we are working with the equipment for forty-five minutes at a time.  The deckhands, while very serious about safety, keep us laughing the entire time.  As I am finishing this entry, we are heading towards home.  It will be nice to be on land again, but I will also miss the many different personalities I was lucky enough to get to know. 

Did You Know?

The Gulf of Mexico covers an area that is about 615,000 square miles.

An area named “Sigsbee Deep” is located in the southwestern part of the Gulf.  It is more than 300 miles long and more than 14,383 feet deep at its deepest point.  It is often referred to as the “Grand Canyon under the sea”.

Sigsbee Deep
The Sigsbee Deep is the darker blue area in the Gulf of Mexico.
Photo credit to

The Gulf’s coastal wetlands cover over five million acres, which is an area equal to about one-half of the area of the U.S.  It is the home to twenty-four endangered and threatened species and critical habitats.

It is estimated that 50% of the Gulf’s inland and coastal wetlands have been lost and that up to 80% of the Gulf’s sea grasses have been lost in some areas.  The continual loss of wetlands (about a football field a year) around the Mississippi Delta, a large land area near where the Mississippi River flows into the Gulf of Mexico, changes how hurricanes impact the coast of the Gulf.  With fewer wetlands to absorb the impact of the hurricane, the hurricanes hit the populated areas with much greater force.

For more facts about the Gulf of Mexico, visit or‎

Thank you for visiting my blog.  I hope you will check back in a few days for an update!

Amanda Peretich: Sad Times With This, My Final Blog, July 22, 2012

NOAA Teacher at Sea
Amanda Peretich
Aboard Oscar Dyson
June 30 – July 18, 2012

Mission: Pollock Survey
Geographical area of cruise: Bering Sea
Date: July 22, 2012

Water collection bottles with samples from CTDs throughout the cruise.

Location Data
Myself: airports, airplanes, and Maryland
Oscar Dyson: Crowley pier in Dutch Harbor, AK

Science & Technology Log
On July 17, as we were “cruising” around 12 knots back to Dutch Harbor, Alaska, I had one more GREAT tie in to chemistry class that I just wanted to share because it was that cool to me! Every few CTDs, a water sample would be collected to later be tested for levels of dissolved oxygen. At the end of the cruise on our way back, Bill allowed me to watch him test those samples using a Winkler titration.

Why do we care how much dissolved oxygen is in the water in the first place? Dissolved oxygen levels provide an excellent indication of the underwater biological activity. If levels are extremely low (2 mg/L or lower), animals fail to survive during this “hypoxia”. If there is no dissolved oxygen at all (0 mg/L), this is known as “anoxia”, meaning without oxygen. Areas that are hypoxic or anoxic are known as “dead zones”. Luckily there aren’t really any reported dead zones around Alaska, but knowing the level of dissolved oxygen is important to the scientists as another piece of data to analyze from this cruise.

How does the Winkler titration work and why did I find it so cool? First off, in chemistry class, we use a buret to add a titrant manually drop by drop into a solution containing a phenolphthalein indicator that turns from clear to pink to signify the endpoint of the titration. On board, the actual titration is automated and there is no indicator! It was nice to see chemistry in action, and even nicer to see the process automated, removing any human error in the actual titration.

Winkler titration
Set-up for the Winkler titration on the Oscar Dyson.

Steps to performing the Winkler titration on the Oscar Dyson:
1. Collect water sample during CTD and add manganese chloride (MnCl2) and sodium iodide/sodium hydroxide solution (NaI/NaOH) to sample. Stopper and mix well.
2. Store all water samples for testing at the end of the cruise (this is how it’s done on the Oscar Dyson to test all samples at once, although you could test them each individually after collection).
3. When ready to test all samples, remove stopper and add magnetic stir bar and 1mL of sulfuric acid (H2SO4). Mix well. If precipitate does not completely dissolve, add more sulfuric acid.
4. Titrate and record results!
5. Repeat steps 3 and 4 for each sample 🙂

Winkler titration bottles
(a) The addition of excess manganese, iodide, and hydroxide ions added to each water sample forms a precipitate (solid), which is then oxidized by the dissolved oxygen in the water sample.
(b) and (c) A strong acid acidifies the solution and converts the iodide ion (I-1) into an iodine molecule (I2), causing the precipitate to dissolve (b) and the solution to turn brownish-orange (c).
(d) The solution is put on top of a stir plate and titrated with a thiosulfate solution. The titration is complete when the solution is neutralized, or there are no more ions remaining in solution. This is determined by measuring the conductivity of the solution because ions allow conductivity so when the solution is neutralized, there will be no conductivity. You can see the conductivity probe in the top of the solution on the right and the thiosulfate being added into the solution through the tube on the left.

Personal Log
My final days/adventures in Dutch Harbor? Enjoy the brief descriptions and photos below!

July 18
– arrived in Dutch early morning to beautiful blue skies all day and I watched as the Dyson docked at Crowley pier
– another Alaskan water adventure when Brian and I donned arctic survival suits, got in Captain’s Bay, and yelled up drafting readings of the water level from various points on the outside of the ship to Neal (while Chelsea took photos)
– went for a run over to Unalaska to see the Russian Orthodox church, walk along the beach, go to Memorial Park, check out some gravestones, and jog around town
– hung out in Dutch with some people off the Dyson, where Brian turned into Billy Idol, Chelsea got a new ‘do, and Kevin got a haircut

July 18: Dutch Harbor, Alaska
July 18: Dutch Harbor, Alaska

July 19
– the day started off looking bleak, and I got covered in mud running back into Captain’s Bay to check out the gigantic oil rig barge
– then it turned into another afternoon of beautiful blue skies to allow me to hike with Brian to the back of Captain’s Bay and up to a really pretty waterfall
– hung out in Dutch with some locals I’d met the night before, including an Aleut with the nose ring and face tattoo

July 19: Dutch Harbor, Alaska
July 19: Dutch Harbor, Alaska

July 20
– was supposed to fly out this afternoon but lo and behold, the skies turned gray, the fog rolled in, all flights in and out of Dutch were cancelled for the day, and I headed back to the ship
– hung out in Dutch with some people off the Dyson and celebrated Patrick’s birthday

July 20: Dutch Harbor, Alaska
July 20: Dutch Harbor, Alaska
July 21: Anchorage airport
July 21: Anchorage airport

July 21
– attempted to get on flights from standby multiple times throughout the day, and finally got on a flight at 8:45pm that got me to Anchorage after midnight, where I slept on a bench in the airport until about 4am

July 22
– no flights out of Anchorage available until almost 9pm! luckily I called Delta, got on standby for a 6am flight where enough people took a later flight (and everyone on standby ahead of me was in pairs) that I got out of Anchorage and to Minneapolis, where I had about 35 minutes to get on standby for another flight that I was able to get on as well; the flight goddesses were with me today
– arrived home to Maryland about 20 hours after leaving Dutch, happy to be back but sad this adventure is officially over

I’d just like to say one last time how AMAZING this adventure was on the Oscar Dyson and how incredibly BLESSED I was to meet such great people and learn some many new and EXCITING things. I owe a huge amount of thanks to plenty of people:
* Thanks to the chief scientist Neal along with Bill and Anatoli for all of the fun science and fish stuff I learned during my shift
* Thanks to the rest of the science party (Scott, Denise, Carwyn, and Nate) for more science and technology that I learned and for the card games I played after my shift and to Kathy for doing her survey tech thing (and helping me find my luggage and get to the airport on time)
* Thanks to the CO CDR Mark Boland for allowing me to be on the OD in the first place and for always seeming to have a smile on your face when I was around
* Thanks to the XO 1M Kris Mackie for all of his help in getting me to the ship, for never sugar-coating life, for a great espresso machine in the galley, and for life lessons, knowledge, and personal growth he probably doesn’t even know he taught me

* Thanks to the OPS LT Matt Davis for reading and approving all of the blogs and for the vast amount of knowledge I gained from him in multiple aspects of ship life
* Thanks to ENS Libby, Kevin, and Chelsea for plenty of information, stories, good laughs, and great memories
* Thanks to LTJG Dave for recommending thought-provoking movies and answering all my questions
* Thanks to the engineering crew (Brent, Tony, Vincente, Garry, Robert, Terry, Joel) for all of their hard work that kept the ship running during the entire trip and for everything you guys taught me
* Thanks to Vince for keeping the internet up and running so I could update my blogs, get on facebook, and let my parents know I was still alive with the VOIP
* Thanks to the stewards Tim and Adam for some of the best cooking I’ve had in a long time and for “encouraging” me try things I didn’t think I liked but wound up enjoying because you made them so delicious
* Thanks to the deck crew (Willie, Patrick, Deeno, Jim, Brian, and Rick) for putting up with my incessant chatter, photo taking, curiosity, and questions, for letting me crash your table at mealtimes, and for every little thing that you’ve each taught me, even if you didn’t know you were teaching me something at the time
* Thanks to GVA Brian for all the photos he took whenever I asked, for the awesome headphones he let me borrow most of the trip, for the knowledge he shared about everything he knew related to boats and fishing, and for adventures kayaking, taking draft readings, and hiking in Dutch
* Thanks to the NOAA Teacher at Sea program for providing this incredible opportunity in the first place
* Thanks to everyone that has been reading (and sometimes commenting on) my blogs

NOAA Oscar Dyson in Captains Bay, Dutch Harbor, AK
NOAA Oscar Dyson in Captains Bay, Dutch Harbor, AK