Tag: copepod

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Rebecca Bell, August 14, 2008

NOAA Teacher at Sea
Rebecca Bell
Onboard NOAA Ship Delaware II 
August 14-28, 2008

Mission: Ecosystems Monitoring Survey
Geographical Area: North Atlantic
Date: August 14, 2008

Weather Data from the Bridge 
Time:   134628 (GMT)
Latitude:  40.33.06N Longitude: 72.47.36W
Air Temp 0C: 22.1
Sea Water Temp:  22.3 0C

NOAA Ship Delaware II
NOAA Ship Delaware II

Science and Technology Log 

We sailed from Woods Hole, MA on Wednesday, August 13, 2008 on the first of three legs as part of the Ecosystem Monitoring Program. There are two main objectives of the cruise. The first is to see how well the fish population is doing by sampling and counting fish larvae. The number of fish is important to the fisheries industry- those folks who bring cod and other fish to your table. The second objective is to monitor the zooplankton population. Fish feed on the zooplankton, so a healthy zooplankton population may mean a healthier fish population. We also are monitoring the physical properties of the water; in this case, salinity and temperature. These influence where fish larvae and zooplankton can survive and where and how far they can be dispersed.

There are 125-130 sites randomly selected for sampling. At each site, a pair of bongo nets are dropped and the two samples are collected side-by-side, for a total of 250-260 samples. One sample is designated for the ichthyoplankton (fish larvae) study, and the other for the study of zooplankton composition, abundance and distribution. Near-surface along-track chlorophyll-a fluorescence, which indicates abundance of phytoplankton (i.e. food for the zooplankton), water temperature and salinity are constantly measured with the vessel’s flow-through sampling system. We will also be collecting a separate set of samples as we approach the Chesapeake Bay. These will be used to study aging of fish larvae.

Zooplankton include both unicellular and multicellular organisms. Many can easily be seen with the naked eye. Zooplankton can be classified in a number of ways. One way is to classify them by life history. Holoplankton are those that are planktonic during their entire life cycle (lifers). Meroplankton refers to those plankton in a developmental stage, like eggs and larvae (shorttimers). These larvae will grow into larger organisms such as jellyfish, mollusks, fish, starfish and sea urchins, crustaceans, copepods and amphipods.

The term “plankton” comes from a Greek word for “wanderer” or “drifter”.1 This may imply that these organisms are passively moved about by currents. However, many can power around on their own, using several different methods such as cilia, muscle contraction, or appendages on the head, thorax or abdomen. They also move vertically in the water column, up toward sunlight during daylight hours and downward at night. Krill (whale food), on the other hand, do the opposite- travel downward during the day and up at night.

The first two samples contained a vast number of salps. A salp is holoplanktonic and is related to sea squirts (urochordates). They are filter feeders, catching bacteria and extremely small plankton in mucous-covered “nets” that act as sieves. Salps are an important part of the ocean food chain.

Samples 3-5 show a greater variety of organisms- comb jellies (ctenophores), arrow worms (Chaetognatha) fish larvae and amphipods. Samples 6-8 are dominated by copepods. There are salps, too, but not nearly as many (about 1/3 fewer) as we saw in the first 2 samples.

So I am looking at these results and wondering: Are there patterns to the distribution of these assemblages? Are salps found in warm water or cooler water?  Does temperature matter at all? Do they like deeper water?  Higher or lower salinity? Combinations of any of these? Are they found where another organism is found?

Personal Log 

We began our first work shift today, er, last night, um, this morning at 3 a.m. I work the 3 a.m. to 3 p.m. shift. That means to bed around 7pm., rise and shine at 2:30 a.m. Well, rise, anyway. Not much shining till later.

As I sat on the deck in darkness, waiting to reach our first sample site, I spotted the light from another ship on the horizon. I watched as the light traveled up a wave, then down a wave then up, up, up, up, still up. I could not believe how high it was going, knowing we were doing the same thing. It’s a good thing it doesn’t feel like that. We are now heading south, back towards the Chesapeake Bay. It is getting hotter and muggier, just like home.

We saw dolphins today. A large leatherback turtle was spotted from the bridge. The 3pm- 3am. shift reported seeing flying fish.

Animals Seen Today 

  • Salps
  • Amphipods
  • Copepods
  • Ctenophores
  • Chaetognaths (arrow worms)
  • Fish larvae
  • Sea butterfly
  • Dolphins
  • Gulls (4 species)

1 Source: Online Etymology Dictionarywww.etymologyonline.com.

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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°.

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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.

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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.

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Joan Raybourn, August 20, 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 20, 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: Based on the caption for photo #6 above, in which direction was the ALBATROSS IV traveling when the picture was taken?

Yesterday’s Answer: Our location at 41.39 N and 67.11 W means our goldfinch was 160 nautical miles from Woods Hole. A nautical mile is equal to one minute of latitude and is slightly longer than an ordinary land mile.

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Science and Technology Log

In addition to collecting zooplankton samples, we also collect water samples and measure the amount of chlorophyll they contain. Phytoplankton are too small to see, but an instrument called a flourometer can measure their presence. The flourometer shines a beam of light through the water sample and measures how much blue light (fluorescence) is present.

This process is fairly delicate and great care must be taken to get a good representative water sample, and then not to contaminate it during processing. Water samples are collected in two ways: some are collected in water bottles that are attached to the bongo cable, and others are collected from a hose that is pumping sea water into the plankton lab.  In picture #1 above, our chief scientist, Jerry Prezioso, is collecting a sample from the plankton lab hose. The sample itself is poured through a filter into the bottle to remove any large particles that may be present. Then 200 ml of the sample water is pumped through a fiberglass filter (picture #2). The filter traps chlorophyll as the water passes through. Even though the large amounts of chlorophyll in land plants gives them their bright green color, the small amounts present in phytoplankton are not visible, so you can’t see it on the filter. In picture #3, Jerry uses tweezers to remove the filter (a small white circle) and place it into a cuvette, which is a small test tube. The cuvette contains acetone, which preserves the sample. Then it is placed upside down in the cooler for 12 to 24 hours, which allows the chlorophyll on the filter to wash out into the acetone.

When the sample is ready to be measured, it is taken out of the cooler along with a “blank”, a cuvette of plain acetone with no chlorophyll present. The two cuvettes must warm up a little before they are read, because water condensation on the outside of the cuvette can result in a false reading. We use the flourometer to take three separate readings. When we do science investigations at school, we determine which factors are constant (kept the same for each trial) and which are variable (the thing you are changing in each trial). In this case, the variable is the amount of chlorophyll on the filter. In order to make sure we are measuring only chlorophyll, we also “read” two constants: a solid standard, which is contained in its own tube and used for every trial, and the blank containing only acetone. After the chlorophyll sample is read, we can compare the three sets of data to see how much chlorophyll is really there. In picture #4, I am putting a cuvette into the flourometer, which will shine a light through it and display a number value. The numbers for the solid standard, the blank, and the chlorophyll sample are all recorded on the clipboard along with data such as date, time, and where the sample was collected. Later, the data will be entered into a computer for further analysis.

Why do we want to know about chlorophyll in the ocean? Well, chlorophyll is produced by plants, in this case, phytoplankton. By measuring the amount of chlorophyll in the water samples, scientists are able to determine how much phytoplankton is present. Since phytoplankton is the base of the ocean food web, it is one more piece of the ocean ecosystem puzzle.

Personal Log

Today I switched from the day watch to the night watch, but the timing was good because we had a long steam between stations and I was able to get a little extra sleep before doing a double watch. While all the scientists usually eat meals together, we work in teams to cover the watches, so I will be working with a different set of people. I am now on watch from noon to 6:00 p.m. and from midnight to 6:00 a.m. We will be working our way north for the next week, and the probability of seeing whales is increasing. That will be exciting!