water samples – NOAA Teacher at Sea Blog

August 23, 2024August 27, 2024

Tonya Prentice: NOAA’s CTD and Carousel, August 20, 2024

NOAA Teacher at Sea

Tonya Prentice

Aboard NOAA Ship Henry B. Bigelow

August 8 – August 24, 2024

Mission: Northeast Ecosystem Monitoring Survey

Geographic Area of Cruise: Northwest Atlantic Ocean

Date: August 20, 2024

Weather Data from the Bridge
Latitude: 42.2212 º N
Longitude: 70.29659º W
Wind Speed: NW at 12 mph
Air Temperature: 19.8° Celsius (67.64° F)
Sea Temperature: 19.3 Celsius (66.74° F)

Science and Technology Log

Monitoring Ocean Parameters with NOAA’s CTD and Carousel Bottle Sampler

The CTD and Carousel Sampler are essential tools NOAA uses to monitor ocean conditions. “CTD” stands for Conductivity, Temperature, and Depth, the primary parameters this device measures. By running profiles of the water column from the surface to the bottom, the CTD helps us understand key ocean characteristics. The Carousel Sampler paired with the CTD allows collection of water samples at depth for laboratory analysis.

What Does the CTD Measure?

Conductivity: Helps determine the salinity of the water.
Temperature: Measures the thermal profile of the water column.
Depth: Tracks how deep the CTD is during data collection.

Together, these measurements give us a detailed profile of the water column, helping scientists monitor what we call “the Big Four” parameters.

Carousel: Collecting Water Samples

The CTD and Carousel is equipped with twelve Niskin bottles, which are used to collect discrete water samples from specific depths. The bottles are numbered 1-12, and are “fired” (closed) at different depths to capture water samples.

For example, bottle 1 might be fired near the bottom (a few meters above the seafloor), bottle 2 at 10 meters, bottle 3 at the determined chlorophyll maximum (C Max), and bottle 4 couple just below the surface. Multiple bottles are often fired at each depth to collect additional water. These samples provide critical data about the ocean’s chemical properties at various levels.

view of the carousel sampler resting on the deck of NOAA Ship Henry B Bigelow at night. A white cylindrical metal frame holds twelve gray cylindrical bottles in a round. The bottles have opened stoppers connected at the top and bottom. the CTD probe, at the center of the round, is not visible. Tonya has added yellow text boxes to label the following: carousel, Niskin bottles, top stopper, valves, bottom stopper. — CTD Carousel Bottle Sampler

Preparing the CTD Carousel Bottle Sampler

Before deployment, we ensure that all the stopper valves at the top and bottom of each Niskin bottle are closed. We also hook the wires at the top and bottom to prepare the bottles to open at the designated depths. Once the CTD is ready, it is carefully lowered into the water, beginning its descent through the water column.

Analyzing the Key Parameters

Once the water samples are retrieved, we focus on analyzing these key parameters:

Dissolved Inorganic Carbon (DIC)
pH
Total Alkalinity (TA)
Nutrients
Chlorophyll

view of a large scientific instrument, a cylindrical metal frame containing a round of tall dark gray sample bottles, suspended over the rail of a ship. The sky and the water are both a dark blue, fading into one another at the horizon. — Lowering the CTD into the water.

photo of a computer monitor displaying a graph; the graph itself is not really readable — Lowering the CTD into the water.

Storing the Samples

After processing, the nutrient and chlorophyll samples are stored in a freezer kept at -80°C (-112°F) to preserve them for further analysis. Mercuric chloride is added to the DIC, pH, and TA samples to preserve them until they are measured in the laboratory. These samples provide invaluable insights into ocean health. The DIC, TA and pH samples help us monitor the effects effects of ocean acidification— which occurs when carbon dioxide dissolves into the ocean. The chlorophyll samples measure the amount of phytoplankton living in the water. Like plants on land, microscopic phytoplankton carry out photosynthesis, produce oxygen, and are at the base of the marine food web.

Understanding these parameters allows us to monitor the ocean’s health and better predict how it may change in the future. For more information on ocean acidification, check out this resource: NOAA Ocean Acidification.

By closely monitoring DIC, TA and pH we can track important changes in our oceans, providing critical data for research and conservation efforts.

Personal Log

Life on a 12-Hour Work Shift at Sea

Working a 12-hour shift at sea might sound intense, but there’s often some downtime between stations and even a few hours after the work is done. The time you get can vary depending on how far apart each station is. Sometimes it’s just enough to process samples before heading to the next station, while other times you have several hours to relax and recharge.

So, how do you spend that free time on a ship? There’s no shortage of options. You could enjoy a movie in the lounge area, dive into a good book, play a board or card game with other crew members, or head to the flying deck to spot seabirds and marine life, or simply take in the stunning ocean views. Another interesting way to pass the time is visiting the bridge, where you can see how the ship is navigated, maneuvered, and commanded.

Let’s not forget “Activities and Crafts with Katy,” which can bring a whole new adventure to your day. Today, this included visiting the lab and looking at the different species of marine organisms that have been collected, such as stingray barbs, dogfish, and scallop shells. Katy then showed us how to make our own Acadian Redfish otolith (ear bone) earrings. “Scientists use the ear stones (bones) as a way to age the fish. Also called otoliths, they are bones found right behind the skulls of bony fishes.” (Smithsonian)

The balance of work and downtime can make those long shifts much more manageable and even enjoyable, offering moments to connect with colleagues and the environment around you in a way that few people get to experience.

view of two rows of large brown comfy-looking recliners facing a tv screen mounted on the wall above cabinets. there is a bookcase off to one side. — The Lounge area.

the flying deck - the uppermost deck on the ship - is bisected by the ship's yellow mast. a tall metal frame appears to be shade structure but may serve additional purposes. There are picnic benches and beach lounge chairs. — The Lounge area.

Did You Know?

“One atmosphere is equal to the weight of the earth’s atmosphere at sea level, about 14.6 pounds per square inch” (NOAA Water Pressures at Ocean Depths). Beneath the ocean’s surface, water pressure increases by approximately one atmosphere for every 10 meters of depth.

To illustrate just how intense this pressure can be, we conducted a simple yet fascinating experiment. We decorated 16 ounce styrofoam cups with artwork, then placed them in a mesh bag attached to the CTD Carousel Sampler. The CTD , along with the cups, was submerged to a depth of about 500 meters (1640.42 feet), where the pressure equals roughly 725 pounds per square inch (psi). We repeated this process by submerging the cups to 200 meters (656.17 feet), which equals about 291.18 psi.

As the cups descended into the depths, the increasing water pressure caused them to shrink dramatically because the air inside the cups was compressed. This simple experiment vividly demonstrates how powerful the forces at play beneath the ocean’s surface can be.

three styrofoam cups in a row on a table or desk surface. the leftmost cup is the standard size, undecorated. The middle cup is 30-40% smaller. It's colored with marker to be a flower scene, with "2024" written around the top rim. The rightmost cup is the smallest, probably less than half the size of the original. It says Go Wildcats, August 2024, Henry B Bigelow. — This is a normal size ounce styrofoam cup (left side). Here is the cup after it was submerged 200 m below the ocean surface (middle). The last cup was submerged 500 m and then again at 200 m (right side).

July 18, 2019

Catherine Fuller: Searching for Water in the Ocean, July 9, 2019

NOAA Teacher at Sea

Catherine Fuller

Aboard R/V Sikuliaq

June 29 – July 18, 2019

Mission: Northern Gulf of Alaska (NGA) Long-Term Ecological Research (LTER)

Geographic Area of Cruise: Northern Gulf of Alaska

Date: July 9, 2019

Weather Data from the Bridge

Latitude: 57° 47.549 N
Longitude: 147° 30.222
Wave Height: 0-1 with swell of 4 ft
Wind Speed: 1.7 knots
Wind Direction: 170 degrees
Visibility: 5 nm
Air Temperature: 13.1 °C
Barometric Pressure: 1014.4 mb
Sky: Overcast

Science and Technology Log

Ana’s Work:

Dr. Aguilar-Islas oversees the iron fish deployment.

iron fish on deck — The “iron fish” on deck…

iron fish in water — ..and in its habitat.

Dr. Ana Aguilar-Islas and her team of Annie, Kelsey, and Carrie are studying how the different sources of iron in the Gulf of Alaska influence its chemical structure. Iron is considered a micronutrient, because it is a nutrient that is needed in lower quantities than silicate, phosphate and nitrate, which are macronutrients. Iron is essential for phytoplankton. Iron does not easily remain dissolved in ocean water, but has a tendency to precipitate and become a particle. It is essential for many functions within phytoplankton, including gene function and photosynthesis, so the presence or absence of iron in the water is an indicator of the viability of the ecosystem.

Testing phytoplankton in both an iron-limited environment and an iron-rich one allows scientists to pinpoint the effect that iron has. The water in the Gulf of Alaska is notable for having more iron, leading to larger zooplankton as compared to areas, such as Hawaii, where the lack of macronutrients in the water means that they’re much smaller. The Copper River plume was an example of a naturally occurring source of iron although its decrease is exponential the farther you move from the plume.

In order to test samples without any contamination from being in an iron ship, Ana’s team created a “bubble” room or a clean space to do testing. Her samples come directly from the “iron fish,” a collection instrument that is towed along the starboard side of the ship, and a pump on deck sends water through a tube that is carefully strung from the “fish” through the hallways and into the “bubble.” The team is testing water samples for dissolved iron, particulate iron, and ligands (naturally occurring structures that bind iron and allow it to stay dissolved in seawater). Both the filtered (any plankton filtered out) and unfiltered samples that Ana’s team collects are also used by other teams to provide context for their own experiments, especially testing the behavior of phytoplankton populations in iron-rich and iron-poor water.

looking in the bubble — The bubble from the outside.

Annie at the bubble — Annie spends many hours patiently taking water samples in the bubble.

The Search for “Perfect” Water

After completing our comprehensive zig-zagging study through the Copper River plume, it was decided to continue on a path south to find HNLC (high nitrate low chlorophyll) water. We’re specifically looking for water with a salinity over 32.4 psu and nitrates over 3 micromoles. Water like this would be low in iron. Normally, the lack of iron is a factor that limits photosynthesis,. However, in areas with these numbers, phytoplankton communities have evolved to survive in an iron-deprived environment.

What Clay, Suzanne and Ana hope to do is to introduce both Copper River iron-rich water and commercially available iron into samples of these communities to see if a “bloom” or a sudden growth in population will occur. It’s been a long search so far, taking us through an offshore eddy, watching salinity numbers slowly creep up as we leave the plume’s fresh water influence behind us. To pass the time, my cribbage board came out and I’ve lost to Pete, Seth and Ana (although I beat Seth once). To help Suzanne and Ana find their water, Seth stitched together a composite satellite picture of the chlorophyll in the Gulf from images taken over the last few weeks. This showed an eddy south of the Copper River plume that provided a possible location for the right sampling of water.

Our initial target was 58 degrees N, 146 degrees W, however, we’re continuing on the journey south to see if we can find the right spot. For a long time, we were towing the Acrobat behind us, trying to get additional readings, however, our speed with the Acrobat is limited to a maximum of 7 kts. Early this morning, the Acrobat was pulled in and we’re now cruising at about 10 kts. We’re supposed to move over to the GAK (Seward) line of waypoints after this, but the joke is that we’ll reach GAK 125, i.e. Honolulu, before we find water that fits the parameters we need.

After careful monitoring of our position and the information screens in the computer lab, it seems that our target water is between 57 degrees 21 minutes N between 145 degrees 42.8 minutes W and 145 degrees 39.9 W. Finding the perfect water is complicated by the number of anomalies in the sea surface. We’re having the bridge go through specific maneuvers to take us back and forth through the target patch of water. As we move through what seems reasonable, Ana’s iron fish will be deployed to start bringing in “perfect” water samples.

Sea Surface Temperature Anomalies — These anomalies represent changes in sea surface temperature, and in turn in the chemical composition of the water. On the map, you can see the lines we’re surveying from left to right: Kodiak, Seward (GAK) and Middleton.

our course — Our zigzag course: the bridge asked if we were making course lines with an Etch-a-Sketch!

Since last night, there has been at least one person stationed in the computer lab with eyes on the underway data display to monitor the salinity and nitrate levels. Today, with Dr. Strom, Clay and myself there, we jump every time the nitrate value does. Once our target patch is isolated, Dr. Strom directs the bridge to zigzag the ship through it to find maximum nitrate values and then radios the iron fish team. It’s 2.1….it’s 2.7…quick! Collect samples! It’s a crazy system, but for now it’s getting us the best results we can, considering the fluidity and changeability of the ocean.

I’m not sure what the bridge thinks about our maneuvers, and we’re all imagining what they’re saying! They have been very patient and willing to go along with requests; they’re pretty used to the demands of scientists in search of specific answers. We’re finding our highest values to be about 3.2 micromoles, and it seems that we’ve also narrowed down the “sweet spot.” In addition, a group of fin whales is moving through the area and is making regular appearances as we trace and retrace our path. At one point, Eric, the captain came down to chat and helpfully volunteered to look up the definition of “zig” and “zag” so that we would have our terminology correct. Is zig the upward progression or the downward one?

Most of the science done on board is carefully planned and prepared for. Methodologies are clean and precise in order to produce specific and incontestable results. Sometimes, however, science requires taking advantage of the situation at hand to find optimum data. Science can be messy and inexact, too, if the end result is finding the perfect drops of water in the ocean.

Personal Log

We are now over the 50% point in our trip. It is a bit ironic that as the science team and the crew get to know each better and develop friendships, both sides are also looking ahead to the end of the trip. It’s been fun to get to know the crew and to discover the personalities that make this ship run so smoothly.

Our weather has been notably calm so far, with today’s nearly flat seas being the smoothest to date. We have fog every day; every day the sea surface temperature is higher than the air temperature. What might that be an indication of? Russ seems to think it’s a fairly unusual pattern. Even though today’s temperature is in the mid-50s, the stillness and reflected light off the surface of the ocean almost make it seem warmer. It looks like we can continue to expect fairly calm seas for the next few days, too. Every day someone posts a weather forecast in the mess hall, and every day the forecast is similar.

fog bank on the horizon — Seeing fog banks on the horizon is a daily occurrence.

We continue to eat remarkably well. Today’s lunch was spaghetti or zoodles with eggplant parmigiana, shrimp, and hot veggies. This week already, we’ve had pecan pies and oatmeal raisin cookies for dessert and apple and berry turnovers for breakfast. The food is definitely one of the benefits of being on this ship!

Did You Know?

The fresh water measured in the Copper River plume equates to a quarter of the yearly excess melt from area glaciers. The question then is, where does the other three-quarters go?

What do you want kids to know about your research?

Ana: There are nutrients in the water that sea creatures need: large nutrients and small ones. The small ones are important because they’re needed more often, like vitamins being a more regular part of your diet than hamburgers.

Sea Creatures seen today:

A small group of fin whales came near us several times during our zigzag maneuvers.

March 28, 2016August 21, 2021

Mary Cook: Day 7, March 25, 2016

NOAA Teacher at Sea
Mary Cook
Onboard R/V Norseman II
March 18-30, 2016

Mission: Deepwater Ecosystems of Glacier Bay National Park
Geographical Area of Cruise: Glacier Bay, Alaska
Date: Friday, March 25, 2016
Time: 6:49 pm

Data from the Bridge
Temperature: 35.1°F
Pressure: 1012 millibars
Speed: 0.2 knots
Location: N 58°52.509’, W 137°04.299’

Science Log

Last night we headed out to open-sea and the waters got a bit rougher. I felt queasy so I took seasick meds and went to sleep. We steamed ahead to open sea and arrived to the site for our ROV dive. But the ROV dive didn’t occur due to a mechanical problem with the ship’s engine, so we headed back into the Bay on toward Johns Hopkins glacier for another round of sampling. Today was a very good day for many of the scientists to get a much-needed rest. The ship’s labs were quiet as we traveled back to the glacier. The ship’s crew on the other hand did not get a break. The ship must still be piloted. The galley work continued with meal preparation. The engine room and all of the ship’s operations were still in working mode.

Once we arrived at Johns Hopkins glacier, the ROV proceedings for the night began. It didn’t take long to find Primnoa pacifica! Samples were being carefully taken and put into quivers until resurfacing in the morning.

ROV Quivers for Samples — ROV samples stored in quivers overnight

There are all sorts of other important work that’s occurring in addition to coral collection. One of those is water sampling.

Amanda water sample — Amanda filters water samples

Scientist/Diver Amanda Kelley helps with filtering seawater collected in a Niskin bottle attached to the ROV Kraken. The Niskin bottle has plugs at both ends that are propped open to allow it to fill with water. When the plugs are tripped, the water at a certain depth is collected and sealed so that no other water will enter that sample.

Niskin bottle demo — Dann Blackwood demonstrates Niskin bottle mechanics

Filtering the water sample will help determine the concentration of particulate organic matter in a given amount of seawater at the same location of the Primnoa pacifica being collected. Scientists are trying to determine if the corals derive their food from the particulate organic matter or chemosynthetic sources. The filtered matter will be used to assess for the presence of nitrogen and carbon isotopes helping the scientists better understand the nutritional pathways of the coral ecosystem within Glacier Bay.

The scientists are measuring as many environmental variables as possible and hoping to link these to the health of the coral in Glacier Bay.

Accurate record keeping is of the utmost importance!
Oh my goodness! There are backups to the backups!

Kathy recording data — Kathy records data and checks the logbooks

Geologist Kathy Scanlon shares that she is putting geographic position data into a Geographic Information System (GIS), a digital mapping system, along with the other data collected such as diver comments and coral samples.

Kathy and GIS — Kathy records data in the Geographic Information System (GIS)

In a nutshell, it’s a way to organize data based on geographic location. In the process of gleaning this information, she says it’s also a great way of double-checking the record keeping for any inconsistencies. Another backup to the backups!
Some of the data points being recorded and re-recorded are date, time, site, depth, species, several reference numbers, and diver’s comments.

In addition to samples of Primnoa pacifica being collected, the divers are gathering samples of other organisms for documentation. These scientist divers are looking for something new—something they don’t recognize—possibly a new species or an extension of a known species location. When they surface with something unusual to them, the excitement is palpable! Everyone on the ship wants to see what’s new!

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Personal Blog

Today I’ve been a bit groggy because seasick meds make me sleepy, but I was glad to avoid the “5-star barfing” as one person described their seasick experience.

I’m so impressed with the enthusiasm for education amongst the people involved with this scientific cruise. Yesterday, I met several people at Bartlett Cove who were reading my blog and keeping up with this research cruise. All the scientists and crew onboard the Norseman II are willing and eager to answer any of my questions.

I got an email from a co-worker, Holly, one of Scammon Bay’s English teachers! She told me that she shared my blog with two of her classes and used it as a journaling prompt. Also, our principal Melissa Rivers, is sharing photos and facts with the entire school on a monitor in the Commons. I so appreciate the enthusiasm from my co-workers and their willingness to help our students learn about this cutting-edge research being done in Alaska. What a wonderful opportunity to learn and expand our horizons together!
Thanks again for your support and interest!

Where’s Qanuk?

On the ROV camera before deployment

Just hanging out!

October 27, 2011April 28, 2021

Stephen Bunker: Science Experiments on the R/V Walton Smith, 20 October 2011

NOAA Teacher at Sea
Stephen Bunker
Aboard R/V Walton Smith
October 20 — 24, 2011

Mission: South Florida Bimonthly Regional Survey
Geographical Area: South Florida Coast and Gulf of Mexico
Date: 20 October 2011

Weather Data from the Bridge

Time: 11:39 AM
Wind direction: North-northwest
Wind velocity: 4.5 m/s
Air Temperature: 23 °C (75° F)
Clouds: Alto cumulus

Science and Technology Log

We left port today at about 6:30 AM, before the sun had even come up. We are headed out to the Florida Keys. The rain has stopped as well as the wind. We left Miami Harbor as the sun was coming up.

Our scientific research will take place along the Florida Keys, a chain of low-lying Islands that arc around the southern tip of Florida. The R/V Walton Smith will stop at predetermined stops and take measurements.

There are many science experiments happening on board. In each post, I will try to highlight a different experiment. I’ll start off with the CTD because it is the experiment that drives our schedule throughout our cruise.

The Conductivity, Temperature, & Depth Instrument. Everyone on board calls it the CTD for short. The CTD schedule is our game plan. At about every 3 -5 hours — night and day — we’ll cycle through a series 3-4 CTD drops.

Lower CDT — These are the instruments on the lower part of the CTD.

On the bottom of the CTD are a number of instruments that give real-time data to a scientist on board the boat. The conductivity part of the instrument measures how much electricity passes through the sea water. Using a mathematical algorithm that takes in account temperature and how much current passes through the water, we can determine the density (salinity) of the water.

Full CDT — The CTD on deck. The grey tubes fill with water.

The top part of the CTD has 12 cylinders that can trap water. Those are the grey tubes you see in the picture to the left. There are lids on the top and bottom of each tube that can be closed with a remote control from inside the boat. In this way the scientists can take water samples from any depth of water.

So, when we arrive at one of these predetermined location we’ll lower the CTD.

Once the CTD is just below the surface of the water and everything checks out, the scientist will radio to the crane operator to lower the CTD to within a meter of the bottom of the ocean. That can be anywhere from 5 meters to over 100 down. As the CTD lowers, the scientist monitors the CTD instrument real-time readouts. Using a graph of the data, he or she will decide at which locations to close the cylinders on its return trip to the surface.

CDT Control Center — Nelson monitors the CTD data as it is collected.

Water sample processing — Cheryl is processing water samples from the CTD.

Once it surfaces, we’ll assist in placing the CTD back on the deck and securing it. We’ll then take water samples from the grey tubes. Those water samples will be analyzed in one of the laboratories on the boat. The water samples will show us chemical properties of the water.

Personal Log

Teamwork works! It takes a lot of teamwork to make things happen on board. Guiding the boat to the precise locations is the easy part for the crew. They have a GPS to help them do it. After they get there they have to maintain the location. That’s hard when currents, wind and waves, move the boat which is the size of a house. Then they delicately raise and lower the CTD.

Dave Diving — Crew member Dave preparing to dive in order to remove ropes caught in the ship propeller.

If something happens, they also need to fix it. They can’t drive it to a repair shop. They have to fix things on the spot. During the night, some ropes from lobster traps got tangled into one of the propellers. One of the crew put on scuba gear, got in the water, and removed the ropes.

The group of scientists have been organized into a day shift from 7:00 AM to 7:00 PM and the other half is on the night shift for 7:00 PM to 7:00 AM. This can be uncomfortable to have to stay awake all night, but it also means they have to sleep during the day. The day shift will also have a heavier work load because there are additional experiments that have to be done during the sunshine.

The bridge of the SV Walton Smith — Crew member Bill at the helm of the R/V Walton Smith

July 4, 2010April 15, 2021

Bruce Taterka, July 4, 2010

NOAA Teacher at Sea: Bruce Taterka
NOAA Ship: Oregon II

Mission: SEAMAP Summer Groundfish Survey
Geographical Area of Cruise: Gulf of Mexico
Date: Sunday, July 4, 2010

Out in the Gulf

Weather Data from the Bridge

Time: 1000 hours (10:00am)
Position: Latitude = 27.58.38 N; Longitude = 096.17.53 W
Present Weather: partly cloudy, haze on the horizon
Visibility: 8-10 nautical miles
Wind Speed: 17 knots
Wave Height: 2-4 feet
Sea Water Temp: 28.6 C
Air Temperature: Dry bulb = 29.2 degrees Celsius; Wet bulb = 26.1 C
Barometric Pressure: 1011.1 mb

Science and Technology Log

The purpose of the SEAMAP Summer Groundfish Survey is to collect data for managing commercial fisheries in the Gulf of Mexico. SEAMAP stands for Southeast Area Monitoring and Assessment Program.

Right now we’re working along the Gulf Coast of Texas, far from the BP Deepwater Horizon oil spill, so we’re not seeing any effects of oil here. However, part of our mission is to collect fish for testing to make sure that oil spill has not impacted the marine life in this area and that the fish and shrimp from Texas are safe to eat. We’re also collecting water samples from this area to use as baseline data for the long-term monitoring of the impact of the oil spill in Gulf.

BT Titration — Analyzing a water sample in the Oregon II’s lab.

There are four main ways the Oregon II is gathering SEAMAP data on this cruise, and we’ve already learned how to use all of them. The main way we collect data is by trawling, and this is where we do most of our work on the Oregon II. In trawling, we drag a 42’ net along the bottom for 30 minutes, haul it up, and weigh the catch.

BT Trawl Haul — Hauling in the trawl net.

We then sort the haul which involves pulling out all of the shrimp and red snapper, which are the most commercially important species, and taking random samples of the rest. Then we count each species in the sample and record weights and measurements in a computer database called FSCS (Fisheries Scientific Computer System).

BT Lab Squid — Logging a sample into FSCS.

Here on the Texas coast, where we’re working now, the SEAMAP data is used to protect the shrimp population and make sure that it’s sustained into the future. Since 1959, Texas has been closing the shrimp fishery seasonally to allow the population to reproduce and grow. The SEAMAP data allows Texas to determine the length of the season and size limits for each species. Judging by our trawls, the Texas shrimp population is healthy.

Another tool for data collection is the CTD, which stands for Conductivity, Temperature, and Depth. The CTD also measure dissolved oxygen, chlorophyll and other characteristics of the marine ecosystem and takes measurements from the surface to the bottom, creating a CTD profile of the water column at our trawling locations. These data are important to assess the extent of the hypoxic “dead zone” in the Gulf of Mexico, and to relate the characteristics of our trawling hauls to dissolved oxygen levels. SEAMAP data collected since the early 1980s show that the zone of hypoxia in the Gulf has been spreading, causing populations to decline in hypoxic areas.

We also use Bongos and Neustons to gather data on larval fish, especially Bluefin Tuna, Mackerel, Gray Triggerfish, and Red Snapper. The Neuston is a rectangular net that we drag along the surface for ten minutes to collect surface-dwelling larval fish that inhabit Sargassum, a type of seaweed that floats at the surface and provides critical habitat for small fish and other organisms.

BT Neuston Strainer — Examining the results of a Neuston drag.

We drag the Bongos below the surface to collect ichthyoplankton, which are the tiny larvae of fish just after they hatch. The Neuston and Bongo data on fish larvae are used for long-term planning to maintain these important food species and keep fish stocks healthy.

Personal Log

This is a great learning experience, not only about marine science but also about living and working on a ship. The Oregon II is literally a well-oiled machine, and the operation of the ship and the SEAMAP study depends on a complex effort and cooperation among the science team, the crew, the officers, engineers, and the steward and cook. Everyone seems to be an expert at their job, and the success of our survey and our safety depends on that. It’s a different feeling from life on land.

Life aboard the Oregon II is comfortable, especially now that I’ve gotten my sea legs.(I was hurting after we set out on Friday in 4’ to 6’ swells, but by Saturday afternoon I felt fine.) The food is excellent and most of the ship is air conditioned. The Gulf – at least the Gulf Coast off of Texas right now – is beautiful. The seas are deep green and blue and teeming with marine life. I’m looking forward to spending the next 2 weeks on board the Oregon II and being part of the effort to study the marine ecosystem in the Gulf and how it’s changing.