water sample – Page 2 – NOAA Teacher at Sea Blog

July 23, 2008March 18, 2021

Jillian Worssam, July 23, 2008

NOAA Teacher at Sea
Jillian Worssam
Onboard U.S. Coast Guard Vessel Healy
July 1 – 30, 2008

Mission: Bering Sea Ecosystem Survey
Geographic Region: Bering Sea, Alaska
Date: July 23, 2008

Last night I went to bed at four, my wake up call was for seven forty five this morning, needless to say if I have a little difficulty explaining micro-zooplankton there is an excuse.Today I am spending time with Diane Stoeker and Kristen Blattner, both from The University of Maryland Center for Environmental Science.

If she is not at the computer Diane is either at the microscope, the incubators or working on her phytoplankton experiments.

Diane and Kristen are studying phytoplankton and micro-zooplankton, and it is amazing how these small components of an oceanic ecosystem are vital for the survival of pretty much the entire environment. Diatoms are small single-celled organisms, called phytoplankton. Diane is studying how fast phytoplankton are eaten by micro zooplankton, and how this “grazing” effects phytoplankton populations.

It is a long process to measure water and extract chlorophyll, Kristen is up for the challenge.

Let’s try a visual

Phytoplankton = the microscopic “plants” of the ocean. These organisms photosynthesize and drift with the current. Although some phytoplankton do have locomotive capabilities they cannot swim again the current.

Diatoms are a type of phytoplankton. Zooplankton = small animals who also move with currents and eat phytoplankton as well as micro-zooplankton.

Now enter Diane and Kristen, they look at phytoplankton to find out what is eating them, predominantly micro-zooplankton, and are even looking at their relationship with zooplankton pee and how it might work as a fertilizer for phytoplankton. What these ladies do is collect samples of sea water once a day. They use a mixture of 20% whole sea water and 80% filtered sea water (which removes most of the algae, copepods and protozoa), and a 100% whole sea water sample.

This is part of the larval stage, nauplius of a copepod.

Kristin then strains both types of water pre and post incubation, and will compare the chlorophyll samples. What Kristin is hoping for is that after 24 hours there will be more chlorophyll in the 20/80 sample indicating greater phytoplankton growth, due in part, to the fact that there are fewer predators (micro-zooplankton) in this water. Micro-zooplankton eat nearly 50-60% of the phytoplankton, which they are fertilizing at the same time. This relationship is fundamental to a healthy oceanic ecosystem; you could even say these micro-zooplankton help sustain the growth if phytoplankton in the ocean.

After the 24 hour incubation, samples are taken for further study back at the lab. One specimen they often see is a heterotrophic dinoflagellate. This guy has no chlorophyll and wants to eat phytoplankton; it is in other words a micro-zooplankton.

This little gem does not photosynthesize and locomotors by the little hair like tenacles.

As I look at the pictures Diane has taken, I am transported to a word that is so small that to tell the difference between plant is animal is very difficult.

Isn't this a great looking microzooplankton, can you see how it moves? — Isn’t this a great looking microzooplankton, can you see how it moves?

Quote of the Day: The great sea has sent me adrift, it moves me, it moves me, as the weed in a great river. Earth and the great weather move me, have carried me away and moved my inward parts with joy. Uvavnuk Eskimo Song

FOR MY STUDENTS: What other areas of study can we focus on while using microscopes?

April 24, 2008April 2, 2021

Scott Donnelly, April 24, 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 24, 2008

Weather Data from the Bridge
Sunrise: 0620 Sunset: 2010
Wind: 10 kts
Seas: 2 ft
Light rain showers possible

Science and Technology Log

As forecasted for Wednesday night the turbulent seas have calmed and the howling winds coming from all directions have subsided. On occasion a large wave smashes into the ship broadside. But, for the most part, it seems like the storm has moved onto land. Sampling operations restarted around 2000 (8pm) last night. This morning from 0100 to 0500 is my sixth 4-hour shift. Today nearshore and offshore CTD and biological sampling continues at different longitudes 124^O29’W to 125^O15’W but constant latitude 43^O07’N. This is called a longitudinal sampling survey. The latitude and longitude coordinates align with the westward flow of water from Coos Bay estuary in Coos Bay, OR. Along these coordinates CTD deployment will reach depths as shallow as 50m (164ft) to as deep as ~2,800m (~9,200ft)! Round-trip CTD measurements will take more time due to progressively greater depths with increasing distance from the OR coast. On my morning shift we collected samples at two stations. At the second station 30 miles from the coast the CTD was deployed to a depth of 600m (1,970 feet).

During Thursday’s afternoon shift (my seventh 4-hour shift) the CTD was lowered to a depth of ~2,700m (~8,860 feet) located 50 miles from the coast. At this distance out at sea, the coastal landmass drops below the horizon due to the curvature of the earth and the up and down wave action. The round-trip CTD deployment and retrieval to such great depths take about two hours to complete. The dissolved oxygen (DO) probe measurements indicate a secondary DO layer in deep water. So how are the continuous data measured by the CTD organized? What are the trends in data? In science graphs are used to organize numerical data into a visual representation that’s easier to analyze and to see trends. Below is a representative drawing of how CTD and wet lab data are organized and presented in the same visual space. Note the generous use of colors to focus the eyes and show the differences in data trends.

What are some trends that can be inferred from the graph above? First, with increasing depth, seawater becomes colder (maroon line) until below a certain depth the water temperature is more or less at a constant or uniformly cold temperature (compared to the surface). Second, the amount of dissolved oxygen (DO) in seawater (green line) is greatest near the surface and decreases, at first slightly then abruptly, with increasing depth below the surface. Third, salinity (red line), which is directly related to conductivity, increases with increasing depth. Furthermore, in general seawater pH (blue line) becomes more acidic (and conversely, less basic) with increasing depth. Last, marine photosynthetic activity as measured by chlorophyll a in phytoplankton (purple line) is limited to the ocean’s upper water column called the photic zone. Below this depth, sunlight’s penetrating ability in seawater is significantly reduced below levels for photosynthesis to be carried out efficiently and without a great expense of energy.

The consistently low (acidic) pH measurements of deep water collected by the Niskin bottles and analyzed on deck in the wet lab are a concern since calcium carbonate (CaCO3) solubility is pH dependent. On this cruise the pH measurements between surface and deep waters show a difference of two orders of magnitude or a 100 fold difference. Roughly, pH = 8 for surface water versus pH = 6 for deep water offshore. This difference in two pH units (ΔpH = 2) is considerable as it indicates that the deep water samples are 100 times more acidic than the surface water. pH is a logarithmic base ten relationship, i.e. pH = -log [acid] where the brackets indicate the concentration of acid present in a seawater sample. A mathematical difference in two pH units (ΔpH = 2) translates into a 100 fold (10^ΔpH = 10²) difference in acid concentration. Refer to the Saturday, April 19 log for a discussion concerning the importance of CaCO3 in the marine environment and the net acidification of seawater.

Personal Log

After the morning shift but before a hearty breakfast of eggs, hashed browns, sausage, bacon, and juice, I hung out on the ship’s port side to watch the sunrise, a memorable mix of red, yellow, and orange painting the sky. It was one of the best sunrises I remember and that’s saying a lot since I live in southern Arizona, where the sunrises and sunsets are the stuff of legends. With the low pressure system having moved over land, the sea was calm and the temperature considerably warmer with no clouds positioned between it and the ocean. Perhaps surprisingly, I haven’t sighted a whale or a whale spout, even in shallower, more nutrient-rich coastal waters. It’s not that I haven’t looked as each day I’ve visited the flying bridge (observation deck) above the operations bridge enjoying the immensity of the vast Pacific.

A flock of albatross have begun following the ship I suspect in hopes of getting a fish meal, mistakenly thinking that the McARTHUR II is a trawler. I saw trash, which I couldn’t identify without binoculars, floating on the surface. Sadly, even the vast, deep oceans and its inhabitants are not immune from humanity’s detritus. The history of humanity and its civilizations are intimately linked to the world’s oceans. This will not change. Humanity’s future as well is linked to its maritime heritage. The oceans have fed us well and have unselfishly given its resources without complaint. Perhaps it’s time we return the compliment and lessen our impact.

April 22, 2008April 2, 2021

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

Science and Technology Log

What’s the significance of the NH Line (Newport Hydrographic, 44^O39’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.

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).

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

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.

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.

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.

April 15, 2007April 1, 2021

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.

October 18, 2006April 1, 2021

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.

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•