Allison Schaffer, September 21, 2007

NOAA Teacher at Sea
Allison Schaffer
Onboard NOAA Ship Gordon Gunter
September 14 – 27, 2007

Mission: Ichthyoplankton Survey
Geographical Area: Gulf of Mexico
Date: September 21, 2007

Weather Data from Bridge 
Visibility: 12 nautical miles
Wind direction: E
Wind speed: 12 kts.
Sea wave height: 1 – 2 feet
Swell wave height: 2 – 3 feet
Seawater temperature: 29.0 degrees
Present Weather: Partly Cloudy

Science and Technology Log 

Today we had the opportunity to try out two new sample methods.  One method is along the same lines as the bongo and Neuston sample but this one is called a methot.  A methot is 2.32 X 2.24 m frame with 1/8” mesh netting.  The total length of the methot net is 43 feet. It’s huge! It works just like regular plankton net where it has a large opening and then as it moves towards the end it becomes more and more narrow and eventually ends at a collection container. The reason this is my first time doing one is because they are usually done only at night and since the net is so large they must be done in fairly deep water. The deck personnel helped us put the net in the water and then we waited.  As the net was brought back on deck, we rinsed it down and collected samples the same way we would a bongo or Neuston sample. Of course with such a large net we collect bigger animals that we would with the other two.  We did collect some fairly large fish along with smaller larvae.  Our collection wasn’t the most excited some of the scientists have seen but to me, it was very exciting.

The second collection we took wasn’t a plankton collection but a water sample.  It is important to know the physical and biological parameters of different areas when collecting. For this, we used a very large (and expensive) piece of technology: a CTD which stands for conductivity, temperature and depth.  The CTD also measures dissolved oxygen and can do all of these measurements without actually collecting any water.  We do however collect water to look at chlorophyll levels.  The CTD frame has three bottles attached to the frame to collect water throughout the water column.  Once we open the bottles on deck and set them, the lab scientist has the capability to fire the bottles shut at different depths. All measurements and water collection happen at three areas in the water column. One data and water collection is done at maximum depth, the second at mid depth at the third just a few feet from the surface.  After all of the data has been collected, the CTD is brought back on deck where we bring the water samples up to the lab to test. It was definitely an exciting day on deck today.

Personal Log 

It has one week since we left port in Pascagoula and I am having such a great time!  I forgot how much fun field work is and how excited I get over the smallest things when it comes to animals.  I am so fortunate to have such an experience and I can not wait to get some samples home to share with our students.  I already have started making some lesson plans!

Addendum: Glossary of Terms 

  • Visibility is how far ahead you can see from the ship.  On a very foggy day you may only have a visibility of 10 ft whereas on a clear day you can see all the way to the horizon, or 12 nautical miles.
  • Wind direction tells you which way the wind is blowing from: 0° is north, 90° is east, 180° is south, and 270° is west.
  • Sea wave height is the height of the smaller ripples
  • Swell height is the estimates larger waves
  • Sea level pressure (or Barometric Pressure) indicates what the trend of the weather has been. High barometric pressure usually means sunny weather and rain can not build up in clouds if they are being squeezed together by high pressure.  Low barometric pressure means rainy or stormy weather is on the way.
  • Present Weather is a description of what the day’s weather is.

– Courtesy of Thomas Nassif, NOAA Teacher at Sea, 2005 Field Season

  • Field Party Chief or FPC is in charge of the team of scientists on board the ship. This person oversees all activities having to do with collection of samples and is the go to person in case anything goes wrong that the scientists can’t handle.  They also act as an extra set of hands when needed.
  • Bongo Net is two circular frames 60 cm in diameter sitting side by side with two 333 micron nets and a weight in the center to help it sink.  At the base of each net is a plastic container used to collect all the plankton that can be easily removed so we can retrieve the samples
  • Lab Scientist is the scientist that stays in the lab to work the computers recording the data on sample time, sample depth and is the one that relays information to the deck personnel about when the nets have hit maximum depth.  They keep watch in case anything goes wrong underwater.
  • Deck Scientist is the scientist out on deck getting the nets ready, rinsing the nets, collecting and preserving samples.  They are the eyes on deck in case anything goes wrong at the surface or on deck.
  • Neuston Net is one net 1 X 2 meters with a 947 micron net.  Neuston samples are done only at the surface and placed in the water for ten minutes.
  • CTD 
  • Photic Zone 

Allison Schaffer, September 18, 2007

NOAA Teacher at Sea
Allison Schaffer
Onboard NOAA Ship Gordon Gunter
September 14 – 27, 2007

Mission: Ichthyoplankton Survey
Geographical Area: Gulf of Mexico
Date: September 18, 2007

Weather Data from Bridge 
Visibility: 12 nautical miles
Wind direction: NE
Wind speed: 18 kts.
Sea wave height: 3 – 4 feet
Swell wave height: 3 – 4 feet
Seawater temperature: 27.5 degrees
Present Weather: Mostly Cloudy

Our sample from one of the bongo collections

Our sample from one of the bongo collections

Science and Technology Log 

I woke up this morning excited and ready to go! My morning doesn’t exactly start bright and early at 6am but tends to start much later around 10am.  The way life on board the boat works for the team of scientists is that there are two teams: the night watch which is from midnight to noon and the day watch runs from noon to midnight. The field party (that’s what the team of scientists on board is called) consists of six scientists and the FPC (Field Party Chief).  I work as part of the day watch along with two of the other scientists.  The remaining three work the night shift. Each of the pre-selected stations is about 30 miles apart, so it takes us close to three hours to commute between stations. Once we arrive at the station, all the sample collections and last about 45 minutes to an hour. After we have completed a station we head back into the lab where we have three hours to wait until our next station. During this time we usually watch a movie, read a book, email friends, family or work, do work, play cards, etc. Or in my case, I like to sit out on the deck and look at the ocean since living in Chicago it’s not something I get to see everyday.

Teacher at Sea, Allison Schaffer, rinsing one of the bongo samples into a glass container to be preserved

Teacher at Sea, Allison Schaffer, rinsing one of the bongo samples into a glass container to be preserved

So this particular morning, I wake up and get dressed just in time for an early lunch before our shift. Today it happens that we reach our station around 11 and since each station takes about an hour, myself and the other scientists from my shift decided we would head up and relieve the night shift early so they can head down for lunch since lunch is only out until noon. Since they had already done the bongo net sampling and preserving, we finished up the station with a Neuston collection. Once we labeled all the samples, I sat down at one of the computers to do some more emailing and started staring out the window in the lab. It was another beautiful day on the Gulf! At least from my perspective it was.  What I didn’t see yet on our horizon was a fairly large storm system was headed our way from the Atlantic across Florida in our direction. We arrived at our second station, did our two sample collections and headed back in for dinner. When we got back in, the FPC said that the Commanding Officer (or CO), Lieutenant Commander Brian Parker, said we were going to be heading south to get away from the storm. He said that was our best bet to avoid any bad weather and that the safety of everyone on board is most important to him.  We would definitely not be able to hit anymore stations on my shift but we now had the rest of the night off to relax!

Bongo nets coming out of the water getting rinsed down by one of the scientists

Bongo nets coming out of the water getting rinsed

Personal Log 

I have been finding some very cool animals in the samples we have collected!  The other deck scientist and I spend more time looking through our sieves to see what caught than we do doing anything else. At our first station we got more jellies—and the stinging ones this time!  But at our second station, we caught a bunch of juvenile flat fish and eels.  And we are getting tons of crabs and shrimp!  Little tiny ones!  It is still amazing to me the variety of what we are finding and the different colors of everything! Bright blue copepods, orange or purple crabs, purple amphipods, silvery blue and yellow jacks, silvery blue half beaks, yellow and gray triggers, pink shrimp, and more!

 

Teacher at Sea, Allison Schaffer, taking wire angle measurements for the bongo nets using the inclinometer.

Allison Schaffer taking wire angle measurements for the bongo nets with the inclinometer

Teacher at Sea, Allison Schaffer holding a cannon ball jelly caught in the Neuston net

Allison Schaffer holding a cannon ball jelly caught in the Neuston net

Allison Schaffer, September 16, 2007

NOAA Teacher at Sea
Allison Schaffer
Onboard NOAA Ship Gordon Gunter
September 14 – 27, 2007

Mission: Ichthyoplankton Survey
Geographical Area: Gulf of Mexico
Date: September 16, 2007

Weather Data from Bridge 
Visibility: 12 nautical miles
Wind direction: NE
Wind speed: 10 kts.
Sea wave height: 1 – 2 feet
Swell wave height: 1 – 2 feet
Seawater temperature: 30.1 degrees
Present Weather: Clear with scattered clouds

NOAA Teacher at Sea, Allison Schaffer, gets ready to set sail aboard NOAA Ship GORDON GUNTER

NOAA Teacher at Sea, Allison Schaffer, gets ready to set sail aboard NOAA Ship GORDON GUNTER

Science and Technology Log 

We left port in Pascagoula, MS and headed toward the coast of Florida’s panhandle to begin our ichthyoplankton survey. The purpose of the cruise is to assess the abundance and distribution of the early life stages of different fish. I am part of Leg II of the Fall Ichthyoplankton cruise.  Leg I took place the two weeks prior.  Throughout the Gulf of Mexico there are 143 pre-selected stations set about 30 miles apart at specific latitudes and longitudes.  They spread across the Gulf of Mexico’s continental shelf in water depth of 6 meters to just over 200 meters.  Some species we are specifically keeping and eye out for are king and Spanish mackerel, red drum, and snapper.

Once we arrived at our first station, I put on my hard hat and got to work.  The first sample collected was done using a bongo frame net.  This is two circular frames 60 cm in diameter sitting side by side with two 333 micron nets and a weight in the center to help it sink. At the base of each net is a plastic container used to collect all the plankton that can be easily removed so we can retrieve the samples.  The bongo net is placed in the water and deployed near the bottom.  We don’t want it to hit bottom though!  The bongo sampler is towed at a 45 degree angle that I, as one of the deck scientists, measure using an inclinometer and report back to the lab scientist.  The time that the bongo is in the water depends on how deep it is at each station.  Once the tow was completed, the bongo was brought back on board and using a sea water hose, I rinsed the net allowing all the plankton to fall into the container to collect any plankton caught in the net.  I removed the collection container and rinsed the sample into a sieve.

Then the fun part! I got to look around and see what we caught.  Our first station was full of jellies! I rinsed the samples and placed them in jars to preserve them for identification back at the lab on land. The next sample I collected was done using a Neuston net.  This is very different from the bongo nets in that it is one large net 1 X 2 meters with a 947 micron net and we sample only at the surface.  The Neuston is placed in the water for ten minutes and then brought back on board, rinsed and preserved the same way as the bongo nets. Once I was done with that I headed back inside where we label everything to make sure all samples have numbers and what equipment was used for collection.  I sat down to email some friends back home feeling a little overwhelmed but excited to get to our next station!

Personal Log 

I am still getting my sea legs and learning as I go.  Since today was my first day on deck, everything was very new to me but that didn’t stop me from jumping right in.  My fellow deck scientist has been very helpful and patient about teaching me everything and making sure I feel comfortable doing the different tasks.  I can’t wait to learn more!

Addendum: Glossary of Terms 

  • Visibility is how far ahead you can see from the ship.  On a very foggy day you may only have a visibility of 10 ft whereas on a clear day you can see all the way to the horizon, or 12 nautical miles.
  • Wind direction tells you which way the wind is blowing from: 0° is north, 90° is east, 180° is south, and 270° is west.
  • Sea wave height is the height of the smaller ripples
  • Swell height is the estimates larger waves
  • Sea level pressure (or Barometric Pressure) indicates what the trend of the weather has been. High barometric pressure usually means sunny weather and rain can not build up in clouds if they are being squeezed together by high pressure.  Low barometric pressure means rainy or stormy weather is on the way.
  • Present Weather is a description of what the day’s weather is.

Courtesy of Thomas Nassif, NOAA Teacher at Sea, 2005 Field Season  

  • Field Party Chief or FPC is in charge of the team of scientists on board the ship. This person oversees all activities having to do with collection of samples and is the go to person in case anything goes wrong that the scientists can’t handle.  They also act as an extra set of hands when needed.
  • Bongo Net is two circular frames 60 cm in diameter sitting side by side with two 333 micron nets and a weight in the center to help it sink.  At the base of each net is a plastic container used to collect all the plankton that can be easily removed so we can retrieve the samples
  • Inclinometer is the instrument which measures the wire angle to insure that the bongo nets are at the ideal 45 degrees.
  • Lab Scientist is the scientist that stays in the lab to work the computers recording the data on sample time, sample depth and is the one that relays information to the deck personnel about when the nets have hit maximum depth.  They keep watch in case anything goes wrong underwater.
  • Deck Scientist is the scientist out on deck getting the nets ready, rinsing the nets, collecting and preserving samples.  They are the eyes on deck in case anything goes wrong at the surface or on deck.
  • Neuston Net is one net 1 X 2 meters with a 947 micron net.  Neuston samples are done only at the surface and placed in the water for ten minutes. 

Joan Raybourn, August 25, 2005

NOAA Teacher at Sea
Joan Raybourn
Onboard NOAA Ship Albatross IV
August 14 – 25, 2005

Mission: Ecosystem Productivity Survey
Geographical Area: Northeast U.S.
Date: August 25, 2005

Personal Log

Today was the last day of our two-week adventure at sea. At dawn this morning, we paused for a while before entering the north end of the Cape Cod Canal. While we have been within sight of land for a day or two, it was strange to see land on both sides of us. The canal was built in the 1930s, and using it to get back to Woods Hole saves at least half a day’s sailing time. Without it, we would have to sail all the way around the “arm” of Cape Cod. We slipped into the canal and eased our way south, back into civilization. We stood on the bow of the ship and watched fish playing in the water, seabirds hovering hopefully over them. People walked their dogs on the path beside the canal, and sailboats passed silently. All was quiet. When a siren split the air, we knew we were back.

The trip through the canal took about an hour and a half, and we were in Buzzards Bay. We made our way through the islands and back around to Woods Hole, to the pier where our trip began. We cleaned the labs and packed our gear and samples to go ashore. At the pier, a gangplank was attached to the ALBATROSS IV so that we could move “all ashore that was going ashore”. We lugged boxes and crates over it to the NOAA warehouse, the EPA truck, and the NOAA van that would take the samples back to the lab in Rhode Island. It was a strange feeling to be back on land. At the beginning of the trip, my body had to adapt to the motion of the ship, and for the first two days I staggered around until I got my sea legs. Back on land, my body had to adapt again; even though my brain knew I was on solid land, the sensation of motion persisted.

And then it was over. By 2:30, everyone who was leaving was gone, and our shipboard community was dissolved. Since my flight home is not until tomorrow, I will stay one more night aboard the ALBATROSS IV. It’s a little lonely now, with everyone gone and no work to do. But I’ve been up since midnight, when my last watch began, and an early bedtime tonight will be welcome. What an adventure this has been! I will never forget my days out on the wide blue sea, with nothing to see but sky and wind and ocean. Whenever city life hems me in, I’ll be able to go back in my mind’s eye, feeling the wind and the sunshine, and watching the endless play of the sea, all the way to forever.

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Joan Raybourn, August 24, 2005

NOAA Teacher at Sea
Joan Raybourn
Onboard NOAA Ship Albatross IV
August 14 – 25, 2005

Mission: Ecosystem Productivity Survey
Geographical Area: Northeast U.S.
Date: August 24, 2005

Weather Data from the Bridge

Latitude: 43°32’ N
Longitude: 69°55 W
Visibility: 8 miles
Air Temperature: 17° C
Wind direction: E (99 degrees)
Wind speed: 5 knots
Sea wave height: 1’
Sea swell height: <1’
Sea water temperature: 18.8°C
Sea level pressure: 1018.0 millibars
Cloud cover: 7/8 Cumulus

Question of the Day: At what degrees on the compass would you find the intermediate directions? (Use information below to help you and look for the answer at the end of today’s log.

Yesterday’s Answer: GMT stands for “Greenwich Mean Time”. GMT is the time at the Prime Meridian, which passes through Greenwich, England. People around the world can use this time as an international reference point for local time. We are on Eastern Daylight Time (EDT), which is four hours behind GMT. At 1:33 a.m. GMT, it was already August 24 in Greenwich, but our local time was 9:33 p.m. EDT, still August 23, so that is the date I used in the log.

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Science and Technology Log

Over the last eleven days, the ALBATROSS IV has zigzagged back and forth across southern New England waters, Georges Bank, and the Gulf of Maine. The collection stations were chosen in advance of the trip and plotted on an electronic chart. So how does the crew drive the boat to the next station?

Ship navigation is a combination of automated and manual tasks. Based on the ship’s current position and the latitude and longitude of the next station, the navigator determines what heading to take. That is, he decides in exactly which direction to go using a compass. The ship has an electronic gyroscope as well as a manual compass similar to the ones you may have seen, only larger. It has a magnetic needle that points north, and is divided into 360 degrees. The cardinal directions are these: 0° is north, 90° is east, 180° is south, and 270° is west. The navigator enters the heading into the ship’s navigation computer, and if conditions are normal, he can set the ship on Autopilot. Then the computer will automatically adjust the ship’s direction to keep it on course.

The fact that the ship is running on Autopilot does not mean that the crew can take a break. The crew sets the ship’s speed depending on weather and sea conditions, and on how much other ship traffic there is in the area. In open water, the ALBATROSS IV cruises at about ten to twelve knots, which means we cover about 10 to 12 nautical miles per hour. The crew must constantly monitor to make sure the ship is operating safely and efficiently. They plot the ship’s course on paper, monitor weather conditions, watch for other ships and communicate with them, and adjust the ship’s course and speed. At the collection stations, they are able to put the ship at the exact latitude and longitude called for, and keep it there during water casts and sediment grabs, or moving at just the right speed for plankton tows.

Navigators keep a constant watch out for other ships, using a combination of visual and radar data. They use radar to pinpoint the ships’ locations, and often can be seen scanning the sea with binoculars. Signal lights on ships help with navigation, too. Ships have a red light on the port (left) side and a green light on the starboard (right) side. This helps navigators know which side of a ship is facing them and in which direction it is headed. Of course, radio communication makes it possible for ships’ crews to talk to each other and make sure they are passing safely.

Personal Log

Tonight will be the last night of the cruise. We expect to be back in Woods Hole by midday tomorrow, two days earlier than planned. We’ve been blessed with excellent weather, and have made good time cruising between stations. I was very excited last night to see fireworks in the toilet! Toilets on the ship are flushed with sea water, which often contains some bioluminescent phytoplankton. Sometimes the swirling action of the water will excite them, and we’ll see blue-green sparkles and flashes as the water washes down. (Sewage and waste water are biologically treated on board so that they are safe to release into the ocean.)

I want to thank the crew of the ship, especially the NOAA Corps officers who have welcomed me on the bridge and answered many questions about ship operations. I am particularly grateful to Capt. Jim Illg, who reviewed all of my logs, and Ensign Patrick Murphy, who answered many questions about weather and navigation.

Finally, I want to thank the scientists who willingly shared their knowledge and patiently taught me protocols for their work. Jerry Prezioso, a NOAA oceanographer, served as chief scientist on this cruise. He helped me prepare ahead of time via telephone and email, and has been endlessly helpful to this novice seafarer. His enthusiasm is infectious, and he has a knack for turning any event into a positive experience. Jackie Anderson, a NOAA marine taxonomist, taught me to operate the CTD unit and helped me identify the kinds of zooplankton we captured in the bongo nets. Don Cobb, an EPA marine environmental scientist, helped me understand the kinds of research the EPA is doing to monitor the health of our oceans and estuaries. Thanks to all of them for their  work in keeping Planet Earth healthy, and for making this an experience I can take back to my classroom and use to help make science real for my students.

Today’s Answer: The intermediate directions are those that fall between the cardinal directions, so to find their degree equivalents, find the halfway point between the numbers for each cardinal direction. Northeast would be at 45°, southeast would be at 135°, southwest would be at 225°, and northwest would be at 315°.

Joan Raybourn, August 23, 2005

NOAA Teacher at Sea
Joan Raybourn
Onboard NOAA Ship Albatross IV
August 14 – 25, 2005

Mission: Ecosystem Productivity Survey
Geographical Area: Northeast U.S.
Date: August 23, 2005

Weather Data from the Bridge

Latitude: 44°23’ N
Longitude: 66°37’ W
Visibility: 10 miles
Wind direction: W (270 degrees)
Wind speed: 12.7 knots
Sea wave height: 1’
Sea swell height: 1’
Sea water temperature: 11.1°C
Sea level pressure: 1014.7 millibars
Cloud cover: 1/8 Clear with a few cumulus clouds low on the horizon

Question of the Day: What does “GMT” stand for and how does it affect the date in the log information above?

Yesterday’s Answer: The clock shows 9:17 a.m. There are 24 hours around the clock face. The hour hand is pointing a little past the 9, so that is the hour. To read the minute hand, notice its position. On a twelve-hour clock, this position would indicate about 17 minutes past the hour. Since this clock counts off 24 hours instead of counting to 12 twice, the afternoon and evening hours have their own numbers. For example, 4:00 p.m. on a twelve-hour clock would be 16:00 on a twenty-four-hour clock. There is no need to indicate a.m. or p.m. since each hour has its own unique number.

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Science and Technology Log

Today I spent some time up on the bridge talking to the crew about weather. The ship collects all kinds of weather data from on-board sensors, including air temperature, air pressure, wind speed and direction, and relative humidity. It also receives weather data from sources outside the ship via satellite link and email. I was especially interested in how the crew determines visibility, cloud cover, sea wave height, and sea swell height, since these represent subjective data. “Subjective” means that someone uses known data and their own experience to make a judgment. Here are some examples.

Visibility just means how far you can see into the distance. This is very hard to judge on the sea because there are no reference points – no objects to “go by” to decide how far away something is. Radar gives an accurate distance from the Albatross IV to objects such as other ships, and on a clear day, the horizon is about twelve miles away. A navigator learns to estimate visibility by combining radar information with how far away objects look in relation to the horizon. It takes a lot of practice to be able to judge visibility using only your eyes!

Cloud cover just means the amount of the sky that is covered by clouds. This is expressed in eighths. Today the cloud cover was about 1/8, meaning about one eighth of the sky had clouds and seven eighths was clear. To make the estimate, mentally divide the sky in half and ask yourself if about half of the sky is cloudy. If you see that less than half the sky has clouds, then mentally divide the sky into fourths, and then eighths. This can be tricky if the clouds are scattered around because it is hard to see a fraction that isn’t all “together”. Once again, this skill takes a lot of practice.

Sea swell height and sea wave height are both descriptors of how the ocean surface is behaving. These are important to observe because they affect the motion of the ship. Swells are large rolling humps of water that are created by the winds from storms. Navigators can tell how far away the storm is by observing the speed of, and length between, the swells. The ship might rock with long, slow swells caused by a storm hundreds of miles away, or with the shorter, faster swells of a storm that is closer. Waves, on the other hand, are caused by local wind; that is, the wind that is blowing right at your location. Waves might just be rippling the water if the wind is light, but can be large if the wind is strong. Both swell height and wave height are estimated in feet from the trough (bottom) to the crest (top) of the wave. Again, this skill takes lots of practice.

Personal Log

Yesterday we got word that a pod of about seventy right whales had been sighted in the Bay of Fundy. This represents a large fraction of this endangered species’ entire population of fewer than 300. Our route has taken us up a little way into the bay, and we have been eagerly watching for whales. We’ve seen several blows in the distance, and occasionally a glimpse of a long back breaking the water. Most of them have been fin whales, but we did see two or three right whales before it was completely dark. It’s exciting to see these giants of the ocean and we hope to see more when the sun comes up.

Joan Raybourn, August 22, 2005

NOAA Teacher at Sea
Joan Raybourn
Onboard NOAA Ship Albatross IV
August 14 – 25, 2005

Mission: Ecosystem Productivity Survey
Geographical Area: Northeast U.S.
Date: August 22, 2005

Weather Data from the Bridge

Latitude: 42°17’ N
Longitude: 69°38’ W
Wind direction: SE (130 degrees)
Wind speed: 10.3 knots
Air Temperature: 19°C
Sea water temperature: 21.8°C
Sea level pressure: 1016.5 millibars
Cloud cover: High, thin cirrus

Question of the Day: What time does the 24-hour clock in picture #7 show?

Yesterday’s Answer: Sediment is composed of all the small particles of “stuff” that sink to the ocean floor. Near the coast, fresh water is flowing into the ocean from rivers and streams, and human activity creates more matter that is flushed into the ocean. Because there are more sources of sediment near the coast, it collects more quickly there than it does in the open sea.

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Science and Technology Log

Advances in computer technology have made the process of collecting plankton and water samples much easier than it was in the past. During a plankton tow or a water cast, many different people are working together from different parts of the ship, and technology makes it easier to communicate, obtain plankton and water samples from precise locations, and protect equipment from damage. The ship’s crew navigates the ship to the exact station location and maintains the location while the samples are collected, there are scientists and crew members on the aft deck handling the collection equipment, a crew member operates the winch to lift and move the equipment, and a scientist operates the computer system that collects data from the Conductivity, Temperature, and Depth instrument (CTD).

The stations, or places where we will collect samples, are designated in advance of the trip and plotted on a computer map. A computer chooses the stations randomly so that we get information from all over the area with no accidental human pattern. The ship’s commanding officer and the head scientist work together to determine the course the ship will take to visit each station. Many factors must be considered, including efficiency, fuel conservation, and weather. Once the course is set, the chief scientist “connects the dots” on the computer map. Then it is easy to see where we are going next, how far away it is, and when we can expect to be there. “Are we there yet?” is a question asked not only by children on vacations, but by scientists and crew at sea!

When the ship approaches a station, the bridge crew makes an announcement so that everyone knows to get ready. “Ten minutes to bongo” means that it is time for the CTD operator to fire up the computer, for the winch operator to get set, and for the deck crew and scientists to get into their gear and make sure the equipment is ready to go. There is a video camera on the aft deck that enables everyone inside to see what is happening on the deck. This makes it easier to coordinate the collection process and to act quickly if there is an emergency.

When the ship is at the exact position of the station, the bridge radios the winch operator. He in turn lets the CTD operator know that we are ready to begin. The CTD person starts the computer program and tells the deck crew to turn the CTD on. The winch operator lifts the equipment and casts it over the side of the ship into the ocean. The “cast” might have just the CTD unit, or water bottles to collect water samples, or the bongos to collect plankton samples. The CTD goes down on every cast since it is collecting data that is important for the success of the tow as well as for further study.

During the cast, the CTD operator watches the computer display to make sure collections are made at the correct water depths. He or she talks to the winch operator over a walkie-talkie so that he knows how far to drop the line and when to pull it back up.  Plankton is collected at about 5 meters above the ocean floor. The ship’s computer tells us how deep the water is and the CTD tells us how deep the instrument itself is. By comparing these two numbers, the CTD person can make sure the equipment doesn’t drag the bottom, which would damage it and contaminate the samples. Once the CTD and the collection equipment are out of the water, the unit is turned off and the CTD operator finishes up the data collection process by entering information such as date, time, latitude, longitude, station and cast numbers. We just finished Station #75, and will be doing our 100th cast at the next station. (More than one cast is done at some stations.) Sample collections at each station can take anywhere from about 20 minutes for a relatively shallow plankton tow to about 2 hours if we are in deep water and collecting plankton, water, and sediment.

During the cast, the CTD operator can watch as the computer creates line graphs showing the data that is being recorded by the CTD unit. In picture #6 above, the line graph on the right shows the depth, while the graph on the left shows the sea temperature in red, the density of the water in yellow, salinity in blue, and fluorescence in green. Density is kind of like how “thick” the water is, salinity is how salty it is, and fluorescence is a measure of phytoplankton. Line graphs show change over time, so we can see how these values change while the CTD is in the water.

Personal Log

Some adaptations take longer than others. Since I switched watches, I have never been completely sure of what day it is, and when I get up in late morning, I’m always surprised to see lunch being served instead of breakfast. However, I have learned to use the physics of the ship’s motion to make everyday tasks easier. Carrying a heavy load up the stairs is easier if you wait for a swell to lift the ship and give you a little boost, and opening doors and drawers, standing up, and even drinking water is easier if you do it with, rather than against, the roll of the ship. As much as I staggered around for the first two days of the cruise, I wonder now if dry land will feel odd when we get there at the end of the week.