Scott Donnelly, April 22, 2008

NOAA Teacher at Sea
Scott Donnelly
Onboard NOAA Ship McArthur II
April 20-27, 2008

Mission: Assembly of Science Team and Movement of Science Gear/Equipment
Geographical Area: Coos Bay to Astoria, Oregon
Date: April 22, 2008

Weather Data from the Bridge 
Sunrise: 0620 Sunset: 2010
Wind: 10 kts, 25 kts gusts
Seas: 4-7 ft
Rain showers possible

Open Niskin bottles on CTD platform

Open Niskin bottles on CTD platform

Science and Technology Log 

What’s the significance of the NH Line (Newport Hydrographic, 44O39’N)? Water and biotic data acquisition at the NH Line began over 40 years ago. The NH Line then is significant on account of the long-term historical sample collection and data sets that it provides. Consequently, temporal (time) comparisons involving water and biotic data can be made over decades as opposed to shorter lengths of time such as years or months. It’s my understanding that nearshore and offshore sampling along the Oregon Continental Shelf (OCS) always includes the NH Line. My second 4-hour shift began at 0100 and ended shortly after 0500. Regardless of time of day each shift sets up and collects water samples from each of the twelve Niskin bottles on the CTD rosette. Typically, three water samples are collected at a particular depth. How does remote sub-surface water sampling work? When the CTD is deployed from the ship’s fantail, initially the top and bottom lids on all twelve Niskin bottles are open as shown in the photo below.

The CTD is lowered into the water and once the desired depth is reached the requisite number of Niskin bottles are closed electronically from the ship by whoever is in the control room. For my shift it’s team leader Ali Helms. After that is done, the CTD then is lowered or raised to another depth where another “firing” takes place and more water samples at a different depth are collected. When sampling is complete, the CTD is raised to the surface and onto the ship where it is secured to the fantail deck. The water in each Niskin bottle is collected and taken to the ship’s wet lab where each water sample collected at a particular depth is analyzed for other water quality parameters not measured by the CTD.

YSI datalogger

YSI datalogger

Other water parameters measured on this cruise in the wet lab include: total dissolved solids (TDS), pH, and turbidity (how transparent, or conversely cloudy, is the water). A YSI 6600 datalogger interfaced with a multi-sensor water quality probe (sonde) is used to measure the aforementioned water parameters. See photos below. The CTD and Niskin bottles then are hosed down with freshwater and reset for the next sampling site.  After the CTD is reset for the next sampling site, then it’s time to collect biotic samples from the surface and at different depths. Biological sampling always follows a CTD cast. On this cruise biological sampling is carried out on the ship’s starboard side just fore of the fantail. Collection of marine invertebrate (boneless) organisms uses nets that vary in size, shape, density of net mesh (number of threads per inch), and volume of detachable sample collection container (called a cod end). Sampling nets are conical in shape and typically are made from Dacron or nylon threads that are woven in a consistent, interlocking pattern. Each specifically designed net is attached to a wire cable and deployed from the starboard side. If collection/sampling is done below the water’s surface (also called sub-surface), a weight is attached to the net’s metal frame.  A bongo net is an example of a net used for the collection of invertebrate marine organisms at some defined depth below the surface (see photos below).

Multi-sensor water sonde

Multi-sensor water sonde

A bongo net collects organisms by water flowing into the net, which is parallel or horizontal to the water surface at some depth below the surface. Consequently, use of a bongo net requires that the ship moves forward. Deployment of a bongo net requires the use of trigonometry, a favorite math course of mine in high school a long time ago. The length of cable let out by the NOAA deckhand operating the winch with cable does not equal the depth that the bongo net is lowered below the surface. (This would be true if the net was simply dropped straight down over the side of the ship.) Let’s use the drawing below to illustrate this.

Suppose sample collection is to be done at 100m (328 feet) below the water’s surface. More than 100m of cable needs to be let out in order to lower the bongo net to 100m below the water’s surface. How much cable beyond 100m is let out (x) depends on the angle (θ) of the net (and hence cable) to the water’s surface. The angle θ is measured by a protractor attached to the cable and pulley at the position identified with the blue star in the drawing. The angle θ in turn depends on the ship’s forward speed. To calculate the length of cable that needs to be let out, the following trigonometric formula involving right triangles is used: sin θ = cos-1θ = 100mx. The calculated value x is communicated to the NOAA deckhand, who controls the winch that lets out the desired length of cable. When this cable length is reached, retrieval of the bongo net begins.

Duel sampling bongo nets ready for retrieval

Duel sampling bongo nets ready for retrieval

The volume of water that contains the marine organisms and that flows through the bongo net is recorded by a torpedo-shaped rotary flowmeter (left photo below), which is suspended by wires or thick fishing line in the middle of the net’s mouth. As water moves past the meter’s end, it smacks into and transfers its momentum to the flowmeter’s propeller, which rotates or spins. The propeller’s shaft in turn is linked to a mechanical counter inside the meter’s body (right photo below). A complete revolution of the propeller equates to a certain number of counts and that is related to a certain volume of water that has flowed past the meter.  The mathematical difference between the two numbers recorded before the net’s deployment and after the net’s retrieval is plugged into a mathematical formula to obtain the estimated total volume of water that flowed through the net’s mouth during the time of collection. Consequently, the weight or number of biomass collected by the net can be related to the volume of water in which the biomass was found. This gives an idea about the density of biomass (weight or number of biomass units per volume seawater, g/m3) in a horizontal column of seawater at a given depth and site. In tomorrow’s log I’ll talk about what marine organisms a bongo net collects (including photos) and also discuss and describe the three other nets used on this cruise to collect marine invertebrates.

Mechanical counter in flowmeter

Mechanical counter in flowmeter

Personal Log 

So far after one full day at sea, I haven’t experienced any indications of sea sickness in spite of rough seas (see weather forecast at beginning of log). Four other science team members haven’t been as fortunate. I didn’t witness any visible bioluminescent surface events on the early morning shift (0100 to 0500). I walked to the ship’s bow since this would likely be the best place to witness bioluminescence given all the agitation of seawater there. I left a bit disappointed but there are still five days remaining. The CTD and both the DO and chlorophyll probes (sensors) operated without any problems.

Bob and I communicate well and have similar personalities and intellectual interests. Before carrying out a task we discuss how it’s to be done and then agree to do it as discussed and in the order discussed. Communication is critical because when sampling for biological organisms for example, the nets have large, heavy weights attached so once the net is lifted from the ship’s deck for deployment the weight is airborne so to speak and free to move without resistance. Getting clobbered in the head or chest obviously would not be pleasant. The bongo net uses a 75 pound weight and the net’s solid metal frame must weigh another 25 pounds. Caution and paying attention are paramount once 100 pounds are lifted from the deck, suspended from a cable free to move about with the rolling and pitching of the ship with only air providing any sort of resistance against its movement.

 Rotary flowmeter

Rotary flowmeter

Bob and I have delegated certain tasks between us. We agreed that when a net is deployed, he will always control the net’s upper halve where the net’s “mouth” and weight are located; I in turn will control the net’s bottom halve where the netting and sample containers or cod ends are located. When the net is ready to be lifted from the sea and returned to the ship’s deck, the tasks for retrieval are the same as for deployment, though in reverse order from deployment. Before the net is lifted shipboard, it’s washed or rinsed top to bottom with seawater from a garden hose that gets seawater pumped directly from the Pacific. Washing is necessary because the collected marine organisms adhere to the net’s mesh so in order to get them into the sample container (cod end) at net’s end they must be “forced” down into the cod end. Once the net is shipboard, the cod end and collected organisms are emptied into a sample jar, sample preservative is added, and the container is labeled appropriately.

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Maggie Prevenas, Week 1 in Review, April 15, 2007

NOAA Teacher at Sea
Maggie Prevenas
Onboard US Coast Guard Ship Healy
April 20 – May 15, 2007

Mission: Bering Sea Ecosystem Survey
Geographic Region: Alaska
Date: April 15, 2007

Week in Review

On Monday, April 9: we loaded the ship with many bags and boxes of gear. Everyone moved into their rooms, unpacked and then headed for the science lab. In order to do science experiments, the scientists had to set up their labs.

The food is yummy onboard the Healy. There are always many fresh fruits, vegetables, beverages and snacks in the galley. Some of the food I have eaten includes fresh mixed fruit, creamy vegetable soup, and lo mein with vegetables. The salsa is to die for. There are fresh baked pies, coconut macaroons, brownies and ice cream.

Tuesday, April 10: we shipped out of Dutch Harbor and steered north. The water has been amazingly calm. We have seen many gulls and some smaller waterfowl. One of the research groups is counting and identifying our fine-feathered friends. Since they don’t have very much equipment besides binoculars, they were busy from the first day out, collecting data.

Wednesday, April 11:  was the first big push for samples from the rosette. Because so many teams need seawater in order to do their experiments, there are many sampling stops. The water is below freezing, but it is still liquid because salt is dissolved. Many of the scientists are using the water samples to test for the concentration of various nutrients and plankton.

Why nutrients? They are one very important limiting factor in the growth of the producers. Yes, without sunshine there’s no life, but algae and other phytoplankton need fertilizers to grow like crazy. Measuring the concentration of these nutrients allow the scientists to check on the health of the ecosystem and make predictions about what might happen to the delicate balance in the Bering Sea.

Thursday, April 12: was a very interesting day because the Ice Seal Team, from the National Marine Mammal Laboratory in Seattle, did some practice runs using the zodiacs. The Healy had never launched zodiacs of this size before so it was practice for the Coast Guard as well. The scientists in the lab were in full experiment mode, working on perfecting their technique or tweaking their new setup.

Friday, April 13: started our rotations through the science labs. We arranged our rotations around the theme of ‘Energy and Nutrient Transfer Through the Ecosystem.’ Dr. Cal Mordy was my first scientist mentor. He is looking at concentration of nutrients and oxygen in seawater. Robyn Staup, the other onboard teacher, was connected with the physical oceanographers, Drs. Nancy and David Kachel and Dr. Ned Cokelet. She fired tubes and learned many different techniques they are using to test the water of the Bering Sea.

The helicopter did a launch from the flight deck on Friday afternoon. The NMML (NOAA) is doing population counts for ice seals in the sea. Much work has to go into creating a flight plan. Time is made to communicate concerns. It was all done right, thanks to the careful attention of Ice Seal Team Leader Mike Cameron.

Today we saw our first ice.

Saturday, April 14: was a trial day for both Robyn and I as we are training for being the Ice Observers for the cruise. We had training in ice observation yesterday, but today we were on our own. Every two hours we look at the ice and interpret what kind and how much. We get help from the Coast Guard as they tell us the visibility in nautical miles and track our latitude and longitude too. We take ice observations as long as the sun is shining in daylight. After the scientists have completed their investigations in May, our ice observations will provide information about how much ice was there when they collected our data. The helicopter did another transect and observed ice seals and walrus.

Sunday, April 15: a great day to submit ice observations and look for walrus and ice seals. The animals are becoming more common and the birds are becoming scarce. Why? There is hardly any open water anymore, we are surrounded by ice.

The Ice Seals had another transect using the helicopter.

Robyn and I are working on the pictures we need for our first Live from IPY event. Our theme will be life on board a scientific research vessel that is also a Coast Guard Icebreaker.We believe it will be at 10:30 Hawaii time, 12:30 Alaska time, 1:30 Seattle time, 2:30 Mountain time, 3:30 Central time, 4:30 Eastern time. We expect to have representatives from both the Coast Guard and our scientists present.

Karolyn Braun, October 18, 2006

NOAA Teacher at Sea
Karolyn Braun
Onboard NOAA Ship Ka’imimoana
October 4 – 28, 2006

Mission: TAO Buoy Array Maintenance
Geographical Area: Hawaii
Date: October 18, 2006

TAS Braun using the Fluorometer to test CTD water samples.

TAS Braun using the Fluorometer to test CTD water samples.

Plan of the Day 

Transit; TAO buoy painting; Testing CTD samples using the Fluorometer

Woke up at 5am to get a head start on the painting. I’d rather work in the morning before the sun comes up.  I finished painting the white strips before breakfast so the crew could flip the buoys over to paint the red on the bottoms before the end of the day. I spent most of my day in front of the Fluorometer testing the CTD water samples.

Ok Learning time: To calculate chlorophyll you need to use the following equation: Chl (ug 1 ) = F*Ve((Fo-Fa)/S)Vf Where F = fluorometer calibration factor

Fo = total fluorescence

Fa = Fluorescence after acid

Ve = extract volume (acetone extract; 10ml)

Vf = filtration volume (volume of filtered seawater in liters; 0.528L

S = sensitivity To obtain Fo we need to fill the cuvette, a test tube-like glass beaker, and place into the Fluorometer.  Record data. Then add 3 drops of 10% HCL to cuvette while still in the fluorometer.  Re-read the fluorescence at the same sensitivity setting.  Record data. Making sure in between samples the cuvette is cleaned with acetone. In completing the equation, we discovered that out here most of the chlorophyll is deeper than in most places.  Let’s get to the basics. The ocean can be divided into five broad zones according to how far down sunlight penetrates:

  • The epipelagic, or sunlit, zone: the top layer of the ocean where enough sunlight penetrates for plants to carry on photosynthesis.
  • The mesopelagic, or twilight, zone: a dim zone where some light penetrates, but not enough for plants to grow.
  • The bathypelagic, or midnight, zone: the deep ocean layer where no light penetrates.
  • The abyssal zone: the pitch-black bottom layer of the ocean; the water here is almost freezing and its pressure is immense.
  • The hadal zone: the waters found in the ocean’s deepest trenches.

Plants are found where there is enough light for photosynthesis; however, animals are found at all depths of the oceans though their numbers are greater near the surface where food is plentiful.  So why is more chlorophyll found deeper the further you travel away from the equator?  Well my hypothesis is because all the nutrients are found in the deep cold layers of the midnight zone.  Near the equator and near coastlines upwelling occurs so the nutrients are brought up to the sunlit zone. As you go further away from the equator less and less upwelling occurs so the phytoplankton is unable to thrive in this sunlit zone. The phytoplankton will grow deep enough in the twilight zone to obtain the nutrients, yet shallow enough where photosynthesis can occur.  I also think that like land plants, too much sun can reduce the growth of the phytoplankton.

Chlorophyll fluorescence is often reduced in algae experiencing adverse conditions such as stressful temperature, nutrient deficiency, and polluting agents.  Phytoplankton photosynthetic efficiency is one of the biological signals that rapidly reacts to changes in nutrient availability as well as naturally occurring or anthropogenically introduced toxins (contaminants).  The results can be used as an indicator of system wide change or health.  I finally finished the samples around 3 p.m. Got in a work out, watched a movie and was off to bed but not before we retarded our clocks 1 hour.  We are now entering my normal time zone.  So close to American Samoa yet so far away•

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.

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.

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!