Tag: phytoplankton

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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 21, 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 21, 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: Why does sediment collect on the ocean floor more rapidly near the coast than it does further out in the ocean?

Yesterday’s Answer: The stern of the ship is at the back, and the sun rises in the east, so the ship must have been heading west.

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Science and Technology Log

On this cruise, there are actually two separate but complementary kinds of research going on. We have two scientists from the Environmental Protection Agency (EPA) who are collecting samples of the sediment on the ocean floor, which will be analyzed both biologically and chemically. Biology is the study of living things, so the scientists will look to see what organisms are living in the top layer of the ocean floor. The chemical analysis will show what non-living substances, mainly nitrogen and phosphorus compounds, are present. Chemicals may occur naturally, or may be a result of pollution. This work gives us information about human influence on the ocean ecosystem.

To collect the ocean floor sample, scientists use a sediment grab (picture #1). The “grab” is lowered into the ocean until it hits the bottom, where the container closes and “grabs” a sample of whatever is down there. Then it is hauled back to the surface and opened to see what has been collected. There could be sand, silt, mud, rocks, and any creatures living at the bottom of the ocean. There are two chambers in the grab. From one chamber, the top 2-3 cm of sediment are scooped into a pot, mixed up, and put in jars for later chemical analysis. This thin top layer will yield information about the most recent deposits of sediment. Near the coast, that sample may represent matter that has settled to the ocean floor over a year or so. Further out, that much sediment would take several years to deposit. The contents of the other chamber are dumped into a bucket and washed through a sieve to remove the sediment and leave only the biological parts.

The sieves used for the sediment sample are very much like the ones used for the plankton samples, but bigger and with larger mesh at the bottom (picture #4). The bigger “holes” in the mesh allow silt and sand to be washed out. Whatever is left in the sieve is put into jars and stored in coolers for later analysis. The sample contains evidence of what lives in the benthic layer, the top layer of the ocean floor. This evidence could be plankton, worm tubes, or remains of once-living animals.

At each station where a sediment grab is performed, three water samples are taken, one each from the bottom, the middle, and the surface of the ocean. One liter of each water sample is filtered (picture #6) to analyze its nutrient content. This process is somewhat similar to the chlorophyll filtering I described in yesterday’s log. The filters are saved to be analyzed in laboratories, which will look for both dissolved nutrients and particulate matter. Dissolved nutrients are like the sugar that dissolves in your cup of tea – you can’t see it, but it’s still there. Particulate matter consists of tiny bits (particles) of things such as plankton, whale feces, plants, anything that might be swirling around in the ocean.

The EPA is primarily concerned with human influences on natural environments. By collecting sediment and water data, scientists can see what substances humans are putting into the ocean, and what effects they are having on the plants and animals living there. This work meshes well with the plankton research work, since the health of the plankton is directly influenced by the health of its environment. Everything in the natural world is connected, and we humans must learn how to balance our wants and needs with the needs of all other living things. If we are not careful about how we use our Earth, we will upset the balance of nature and create negative consequences that we may not see for years. For example, if chemicals dumped into the ocean (on purpose or accidentally) kill large numbers of phytoplankton, then the entire food web will be disrupted in a kind of ripple effect, like a stone dropped into a pond. The zooplankton (who eat phytoplankton) will starve, and the animals that eat zooplankton will either starve or move to a different part of the ocean, which in turn changes that part of the ecosystem. From this very small example, maybe you can see how huge our responsibility is to keep our oceans (and other environments) clean.

Personal Log

I am so grateful to Jerry Prezioso, our NOAA chief scientist, and Don Cobb, our EPA scientist. They have included me in all of their operations from Day 1, and have been infinitely patient with my many questions. They have explained things over and over until I “got it”, from procedures for collecting samples to the science behind all their work. It has been eye-opening to be on the student side of learning. Many times I have not even had enough background knowledge to know what questions to ask, or have been almost paralyzed with fear that I might do something wrong and skew someone’s data. I know this experience will help me better understand my students who go through these same feelings of anxiety and joy when they are learning something new.

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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!

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Joan Raybourn, August 19, 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 19, 2005

Weather Data from the Bridge

Latitude: 40’ 17” N
Longitude:  70’ 08” W
Wind direction: NNE (29 degrees)
Wind speed: 19.6 knots
Air temperature: 19° C
Sea water temperature: 22.8°C
Sea level pressure: 1018.1 millibars
Cloud cover: cloudy

Question of the Day: Yesterday a goldfinch visited us, but we are far out to sea. When I took the picture above (#6), our position was 41.39 N and 67.11 W. About how far was this little guy from Woods Hole, Massachusetts?

Yesterday’s Answer: Qualitative data is the “what” that your doctor can observe but not necessarily measure. She might look in your ears, eyes, and throat, feel your internal organs through your abdomen, observe your spine, test your reflexes, have you balance on one foot with your eyes closed, and ask general questions about how you feel. Quantitative data is the “how much”; it is something that can be measured. Your doctor will probably measure how tall you are and how much you weigh, and take your temperature and your blood pressure. If she takes blood or urine samples, they will be analyzed for both qualitative and quantitative properties. We are observing and recording similar kinds of data about the ocean, so scientists can get a good picture of the health of this ecosystem.

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Science and Technology Log

We are very fortunate on this cruise to be able to deploy a drifter buoy. The NOAA Office of Climate Observation (OCO) established the Adopt-a-Drifter program in December 2004. The program makes buoys available to teachers who are participating on cruises as Teachers at Sea. Our drifter has been adopted by my school, Greenbrier Intermediate School of Chesapeake, Virginia, and by Julie Long’s school, Farnsworth Middle School of Guilderland, New York. We named him (It’s a buoy!) Moose in honor of the fact that he was deployed in the Georges Bank area of the Gulf of Maine, which has a number of GOMOOS (Gulf of Maine Ocean Observing Systems) buoys. Moose is the fourth drifter buoy to be deployed as part of the NOAA program, and joins over 1,000 drifter buoys collecting data worldwide.

The buoy itself is a blue and white sphere about the size of a beach ball. It is attached to a drogue, a long “tail” that hangs below the buoy and ensures that it is drifting with the surface currents and not being pushed along by the wind. The buoy is equipped with a water temperature sensor, and a transmitter so that its position and temperature data can be beamed to a satellite, which relays this information to a ground station that will place it on a website. Julie and I decorated the buoy with our school names and signatures – it even has a Greenbrier Intermediate School sticker and a picture of our panther mascot. Then we deployed the buoy on August 18 by tossing it over the side of the ship while it was moving slowly. It was a little sad to see Moose drifting off without us, so small on the huge ocean, but we can follow his adventures for the next 410 days by checking the Adopt a Drifter website. You can begin tracking it here. You can find Moose by clicking on his WMO number, which is 44902. The website will give you the location of the buoy (latitude and longitude) and the date, time, and temperature of the surface water at that location.

What can scientists do with the data about surface water currents that buoys such as Moose are collecting? Of course it can be used to track major ocean currents. Knowledge of currents is useful for understanding the ocean ecosystem and for navigation. But this data will also be used to build models of climate and weather patterns, predict the movement of pollution spills, and even to assist with forecasting the path of approaching hurricanes.

Personal Log

I finally feel like I am becoming useful as a scientist on this cruise, not just an interested observer. Although I have been busy helping from Day 1, I am gaining confidence about conducting some parts of the work on my own. I have learned to collect and preserve the plankton samples, process water samples for chlorophyll, and operate the CTD (Conductivity, Temperature, and Depth), a computer linked instrument that measures oceanographic data. This morning I was up in time to watch a beautiful sunrise and had time to do a load of laundry during a long steam between stations. We had a raft of seabirds sitting hopefully off the stern while we were stopped for some work, and the weather is cool and sunny. It’s a beautiful day in the neighborhood!