Tag: oceanography

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Jillian Worssam, July 19, 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 19, 2008

Numerous times over the past two and half weeks I have mentioned the CTD, small ones attached to moorings, there is one on the MOCNESS, there are even CTD sensors aboard the HEALY, but what does this CTD really tell the scientists?

For every sampling station the CTD needs to be prepared ahead of time so that all the equipment is functioning fully.
For every sampling station the CTD needs to be prepared ahead of time so that all the equipment is functioning fully.

As a review, let’s remember that a CTD records the Conductivity of the water that when adjusted for Temperature gives us salinity. The Depth of each sample is recorded because the ocean is not static; it is constantly moving both vertically and horizontally, and changing as it moves. When you sample with the CTD you can add a variety of accessory sensors to measure other ocean parameters: O2 salinity, temperature, pressure, fluorescence, turbidity and on our specific cruise we are also collecting data in regards to micro-zooplankton, nitrates, iron, and radon.

Each line represents a different element that the CTD is measuring.
Each line represents a different element that the CTD is measuring.

Let’s stop for a moment and talk about ocean currents. There are three ocean currents that affect the ecosystems of the Bering Sea: The Alaska Coastal Current, heavily freshwater, colder runoff that shoots through Unimak Pass; The North Pacific Gyre, warmer(relatively) water that seeps through the entire Aleutian chain, like water through a sieve. And the deep ocean conveyor belt, this one actually comes from the Mediterranean…water that has not seen the surface for a thousand years or more! This dense and cold fluid flows through Kamchatka pass, and has traveled from the north Atlantic through the Pacific to get to the Bering Sea, and is really rich in nutrients. No wonder it takes a thousand years. Anyway here we have all this water filtering into the Bering Sea, and here on the HEALY we have the CTD to give us precise data on the composition of this water.

The scientists all getting their water samples out of the 30 liter bottles.
The scientists all getting their water samples out of the 30 liter bottles.

During the actual cast of the CTD at each recorded station 24 data points are collects each second, giving an excellent representation of each specific water column. It is Scott’s job to run the CTD and let me tell you this is no easy task. The electronic equipment has to be constantly calibrated, the physical instrument array maintained, and all the collected data cataloged and stored for transmission to all the scientists both during and at the end of this cruise. None of this is an easy task. I also find Scott’s role on the vessel fascinating. Scott is an engineer who works for Scripts out of California and is hired on as outside technical support. He is not technically one of the scientific team, not technically part of the U.S. Coast Guard, and the HEALY could not technically collect most of their data with out him!

Hamming it up, Scott shows us the real science behind the CTD.
Hamming it up, Scott shows us the real science behind the CTD.

Quote of the Day: If you plan for a year, plant rice. If you plan for ten years plant trees. If you plan for 100 years, educate your children. Chinese Proverb.

FOR MY STUDENTS: What is a pycnocline?

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Chris Harvey, June 6, 2006

NOAA Teacher at Sea
Chris Harvey
Onboard NOAA Ship Oscar Elton Sette
June 5 – July 4, 2006

Mission: Ecosystem Survey
Geographical Area: Central Pacific Ocean, Hawaii
Date: June 6, 2006

Science and Technology Log 

I survived the night with ease! The only problem I had was after I woke up the first time (around 1:30 AM) and could not fully get back to sleep.  I am still struggling with this jetlag thing, although my “sea legs” are coming along well.  Knock on wood; I am already well adjusted in the inner ear, though I still get tossed around a bit when I try to walk. I can handle that though. It is the seasickness that I feared.

I ate breakfast with Amee and John, the Electronics Technician guy.  He handles all of the communications and electronics stuff on the ship.  We all traded past war stories and somehow ended up in a pseudo-philosophical discussion about science and technology and the future of our world. (I say “pseudo-philosophical” because none of us is trained in any way in philosophy!) Yeah, we are all science geeks!  But it was fun. I am learning that everyone on the ship is very kindhearted and friendly.  I guess you have to be if you are going to live in such close quarters together for so long.  I’ve begun to think of this ship in terms of reality shows (Not that I am a fan of them, but we are under a lot of the same conditions: many strangers with unique backgrounds put together in a strange situation, forced to share resources in close conditions, while attempting to complete a task or mission in a given amount of time.).  I will attempt to document the human element of this trip as much as the scientific.  After all, is observation not a key element to the scientific method?  So far we are drama-free, aside from losing Tonatiuh.  But there are still 30 days left.

On a more concrete note, we are headed towards Necker Island, to the northwest of Oahu.  Unofficial word is that we will be there by mid-afternoon.  Although I have also heard that we have another full day of transit.  When we arrive there, we will begin baiting and setting lobster traps. Our mission on the OSCAR ELTON SETTE is to trap lobster in the Hawaiian waters, take measurements of tagged lobsters, and keep track of the overall population density of lobsters in the given areas.  My colleagues are concerned that the number of lobsters in the area is remaining low despite the fact that the waters have been off limits to commercial fishermen since 1990.  They are hoping that, each time they come out here, there will be a sudden increase in the number of lobsters in the area.  Something must be keeping the population down, and through the data we collect, we will be able to contribute to determining the cause, and therefore be able to help scientists devise solutions to stabilizing the lobster population.

Until we reach Necker Island, it is smooth sailing across a gently rolling Pacific, upon my perch on the Marine Mammal Observation Deck, the highest deck set directly above the bridge and which is intended for use for scientists to search for whales, dolphins, and other such life. It is covered, with a nice breeze, and Garret, a fellow researcher, is playing his harmonica.  Life couldn’t get much better.

On that note: Bob, the Chief Scientist onboard the ship (my “boss” so to speak) has made it rather clear to me that when the time to work comes, I will be working hard alongside everyone else. “I don’t know what they told you about the Teacher at Sea program,” he told me over the phone when I first arrived in Honolulu.  “But you are not going to be just observing. You will be getting hands on and dirty.”  “Good,” I told him with a smile on my face.  “That’s why I am here.”  I imagine that when we arrive at Necker Island the pace of life will pick up rather dramatically.  Until then, I am going to work on learning the ropes and enjoy my time with good company.

We have stopped the ship so that we can take a CTD reading.  The CTD reading is a measure of Conductivity, Temperature, and Depth of a water sample between the surface and 500 meters below the surface.  I was very interested in this because 1) it is the first time we have stopped the ship since we made our run out of Honolulu and a change of scenery is great when you are on a ship; and 2) the information that comes back from a CTD is very relevant to the information that I cover in my Earth/Space Science class (Mother, you will have to find some answers to questions I will pose, since some of the data contradicted my thoughts of what it should be.)

The data we are collecting is part of a time series, meaning that we are taking the sample at a specific point that has been sampled in the past and will be sampled in the future.  Scientists can then use the data over time to make inferences about such things as an approaching El Nino or La Nina, suitable regions for supporting animal populations, and other such conclusions based on our basic oceanographic data.  In addition to temperature and depth, the CTD measures the amount of oxygen and chlorophyll in the water, as well as the ocean’s salinity. Why is this data important?  We’ll get to that in a minute.

The CTD is nothing more than a weighted contraption with sensors built into it.  It is picked up by a winch and then released at a rate of 60 meters per minute to a maximum depth of 500 meters.  For this trip, we are going to take four CTD readings.  It is a secondary mission for us, meaning the only reason we are doing it is because we happen to be in the area. As the CTD increases in depth, these are some things I would have expected to see:

1) Temperature should decrease (the deeper it goes, the further it is from sunlight)

2) Chlorophyll count should decrease (Chlorophyll is dependent upon sunlight as well. This is the same chlorophyll that is found in green plants on the solid earth, and is important because it is the most basic form of life for the aquatic food chain. Thus, the more chlorophyll, the greater the chance that an aquatic food chain could be established and supported in a given region of water.  No chlorophyll would indicate a region of water that would most likely not be able to sustain life- i.e.- without chlorophyll there would be no plankton.)

3) Salinity should increase (Saline water is more dense than fresh water, so more saline water should be found at greater depths than less saline water)

4) Oxygen should be found in greatest abundance wherever chlorophyll is in greatest abundance. (Remember from Biology 101, chlorophyll takes carbon dioxide and sunlight and converts it to oxygen)

What actually happened was this:

1) Temperature did in fact decrease with depth, though only slightly.  We were at a depth of over 4,000 meters and we only sent the CTD down 500 meters.  Imagine what would have happened if we sent it down further!

2) The chlorophyll count went from about zero to its maximum at 100 meters, and then returned back to zero by 200 meters depth. This makes sense since most of the sunlight is absorbed by 200 meters.

3) The salinity of the seawater increased at first, then decreased, and ultimately ended up about the same as at the surface.  This is the question I pose for you Terry (ask Marge for some assistance!): Why?  One of my colleagues, smartalec Amee, told me that it was because the Coriolis effect was stirring the ocean between depths of 0-500 meters.  Is this true?  (Remember, Amee is British so I must second-guess ANYTHING and EVERYTHING she says!)

4) Oxygen followed the same suit as I suspected and was at greatest concentration where the chlorophyll was at greatest concentration.

It was very interesting to conduct this investigation because the data that I use in class comes from surveys such as ours.  This was another exciting science-geek moment for me because I seem to forget quite often that I am on a NOAA research vessel conducting the research and acquiring the data that many science resources across the world become dependent upon!

On the sociology side of things, our reality show would never cut it back in the States.  It seems that we all just get along too darn well!  No matter what we seem to say or do to each other, everything seems to come out positive.  Imagine having classrooms with environments like this!  Imagine communities cooperating like we do!  Imagine entire cities or states or countries, or God-forbid, the entire world!  The words of John Lennon come to mind: “…Imagine all the people…”  I guess I am in a utopia of sorts, where life is different only for the time being.  But just imagine!

…you may say that I’m a Dreamer, but I’m not the only one…

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Rachel Dane, May 4, 2005

NOAA Teacher at Sea
Rachel Dane
Onboard NOAA Ship Ka’imimoana
April 29 – May 10, 2005

Mission: Oceanographic Survey
Geographical Area: Puerto Ayora, Isla Santa Cruz, Galapagos
Date: May 4, 2005

Plan of the Day
0400: 1.5N CTD
0830: 2N Recovery and deploy with CTD, AOML and ARGO
2215: 2.5N CTD

Weather Data
Latitude: 1 degree N
Longitude: 95 degrees W
Visibility: 12 nautical miles
Wind Direction: 153 degrees
Wind Speed: 10 knots
Sea wave height: 1-2 feet
Swell wave height: 2-3 feet
Sea water temperature: 27.9 degrees C
Barometric pressure: 1013.2
Cloud cover: 5/8 cumulus, altocumulus

Science and Technology Log 

Last night I ended up falling into bed, exhausted, around midnight.  Jim and I spent almost an hour having a super fun conversation about river running in Idaho and the Grand Canyon—I had no idea that he and I were both guides on the main fork of the Salmon River in Idaho!  It was a wonderful talk, and I hope to have the opportunity to chat more together.

It’s another buoy day; today we will be recovering a damaged buoy and deploying a new one in its place. Each TAO buoy is moored to the bottom of the ocean using Nilspin, which is steel cable surrounded by a protective plastic shield.  Old railroad wheels are used as anchors for each buoy in the array.  The Nilspin cable is also equipped with sensors at various depths; these sensors transmit data from the ocean to the surface of the buoy. Remember, these buoys constantly collect data on wind speed and direction, air temperature, relative humidity, rainfall, barometric pressure, sea surface and subsurface temperature, salinity, water pressure and ocean currents.  The data is gathered and transmitted via NOAA satellites, and is used by scientists all over the world who are studying the relationship between the Pacific Ocean and climatic changes.

Buoy recovery is a fairly labor intensive process that involves lassoing the floating toroid, craning it aboard, spooling in all of its cable, and cleaning the entire apparatus.  Being submerged for 6 months at a time, the buoys acquire quite a collection of barnacles!  Before a buoy can be recovered the anchor needs to be dropped; a sensing apparatus on its underside is responsible for detecting the “drop anchor” signal transmitted by the ship.  In today’s case, the recovered buoy will be stored on deck until it is cleaned, painted, and outfitted with new instrumentation; it will then be standing by, ready to replace another buoy on the array if necessary. There was some excitement today during operations when the anchor release signal was not acknowledged by the buoy—the ship’s winch was very unhappy about having to haul up the additional 2.5 tons of anchor weight!

Deploying a buoy involves all of the same steps as recovery, but in the reverse order.  First, one end of the spooled cable is attached to the bottom of the buoy’s 2.5m diameter base. The buoy is then lowered into the water and the cable is unspoooled.  Finally, the anchor is dropped. The entire buoy lifting and lowering process is done with the large cranes and winches that the KA is equipped with.

Personal Log

All hands involved in the buoy ops functioned together like a well oiled machine.  There is no doubt that everyone on board is familiar with their duties and responsibilities, and all know what needs to be done and precisely when it needs to happen in order for the procedure to be successfully executed.  It is definitely impressive. Again today, all crew members were more than happy to include me in the excitement, and all were very patient with this rookie sea-goer!  Thank you, everyone!

The weather here at the equator is much less humid than I expected.  In fact, I find it quite pleasant; maybe because there is always a sea breeze blowing.  The inside of the ship sometimes feels like a refrigerator, especially the computer and science labs which are kept cool to maintain the machines.

Teams are made and times are set; let the tournaments begin!  For the remainder of the cruise we will be competing against each other in scrabble, cribbage, darts, poker, and a card game called Sequence.  My first challenge is tonight at 6:30—Fred and I play cribbage.  Personally, I can’t wait to see the dart competition as we rock and roll our way to Mexico!

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Rachel Dane, May 3, 2005

NOAA Teacher at Sea
Rachel Dane
Onboard NOAA Ship Ka’imimoana
April 29 – May 10, 2005

Mission: Oceanographic Survey
Geographical Area: Puerto Ayora, Isla Santa Cruz, Galapagos
Date: May 3, 2005

Plan of the Day
0300: 0.5S CTD
1200: Equatorial mooring repair followed by a deep CTD and an ARGO
1845: 0.5N CTD
2345: 1N CTD

Weather Data
Latitude: 0 degrees N
Longitude: 94 degrees W
Visibility: 12 nautical miles
Wind Direction: 150 degrees
Wind Speed: 12 knots
Sea wave height: < 1 foot
Swell wave height: 2-3 feet
Sea water temperature: 26.5 degrees C
Barometric pressure: 1013.0
Cloud cover: 2/8 cumulus, cirrus

Science and Technology Log 

Today is my first full day on the KA’IMIMOANA (KA).  After sleepily answering my 3:30 AM wake-up call and quickly grabbing a hot cup of caffeine, I met Shawn and Jay on deck to begin the first CTD cast of this second leg of the KA’s journey along the equator. CTD is an acronym for “Conductivity, Temperature, Depth”; it is essentially an analysis of the salinity and chlorophyll levels of a site specific water sample. The casts are performed at each 1 degree change in latitude along the entire TAO array.  The CTD “package” consists of 15 cylinders, each about 1.25m high, attached to a sensing apparatus. Based on commands from the deck, this sensing apparatus will open and close the cylinders and provide real-time data of water conductivity, temperature, density and salinity. For the purposes of this morning’s sample, the package was lowered to a final depth of 1000m for sample collection.  Final depths vary with each cast.  Once the cask is deployed, data analysis of the water sample is displayed graphically on a nearby computer—this morning I was able to view a graphical representation of the thermocline for the first time!

Before lunch, I shadow Doc during her weekly safety inspection.  What a great opportunity for me to see the inner workings of this impressive vessel!  After lunch, the announcement that we have arrived at the site of our first buoy repair comes echoing over the loudspeakers, and it’s buoy time!

The equator! For me, it’s no longer simply a line around the globe.  Not only does the equator represent the dividing line between the northern and southern hemispheres of the earth, but this is also the region where Pacific ocean currents are being extensively studied by NOAA in order for us to better understand the relationship between the oceans and climate.  Essentially, the TAO buoy array acts as a 6000 mile antennae that scientists use to monitor ocean trends.

Donning hard hat and life jacket, I ran to the third deck clutching my zip locked camera and climbed into one of the orange work rafts attached to the KA’s port side.  We (Dave, Brian, Chris, Matt and I) were gently lowered into the water by attentive crew members, and off we motored to our waiting buoy, about 75m away.  Unfortunately, this buoy had been damaged by a fishing vessel so Dave and Brian had some repairs to make.  Fish prefer to swim in the vicinity of buoys because schools feed on the growth that accumulates on the underside, and it is quite common for large fishing vessels to tie up to TAO buoys; oftentimes damage occurs in the process.  After the repairs were complete, I was enthusiastically invited to jump onto the mooring buoy, and it was the absolute highlight of my day! Since fish like to hang out by the buoys sea birds do too; this was immediately obvious to me once I had hopped onto the platform and was clinging to the rungs of the tower.

The entire apparatus was covered from top to bottom with dried guano, and within minutes of climbing and perching on the tower, so was I!  Kind of gross; however, this did not prevent me from reveling in the experience of being on the equator and bobbing like a cork, completely and utterly surrounded by water.  It felt as though I had stepped into a completely foreign liquid universe.  Other than our work boat, the only object in the panoramic view was the KA’IMIMOANA headed towards the horizon. I believe that I could have very happily floated on that buoy for the rest of the day, reveling in the vastness.

Once back in the orange raft, our expert coxswain Chris kicked it into turbo gear and off we sped on a high speed chase, in hot pursuit of our ocean home.  Although the KA remained in sight for the entire operation today and although I longed for more time bobbing in the serene, blue stillness of the equatorial Pacific, there was a feeling of extreme comfort in riding to port side of the mighty Ocean Seeker.  Looking up, we saw 10 of our crew members peering anxiously over the rails on all decks, ready to work together to bring us home safely.

Personal Log

On a daily basis, I continue to be amazed by this ship.  So many aspects of life aboard the KA’IMIMOANA are extremely refreshing: that it is a floating home that operates so efficiently through the patience, teamwork and cooperation of all hands, that a hallway passing almost always evolves into a friendly conversation, and that crew members are consistently willing to share their knowledge and experience with me and excitedly teach new information.

Despite my best intentions and despite a 4.5 mile run on the treadmill, I was not able to squeeze in a rest this afternoon. Now it’s 10:30pm and I’m feeling exhausted, but too overwhelmed to sleep.  This evening I studied the Southern Cross and surrounding constellations with Don. Although I live at the Grand Canyon and regularly study extremely impressive night skies, the stars here rival what I’ve become accustomed to at home.  Thanks to Jimbo’s call I watched over 100 squid swarming on our starboard side, and kudos to Tony–his expert fishing skills have ensured that we will all enjoy fresh calamari tomorrow night!  Matt was the first person to introduce me to an actual example of bioluminescence tonight, visible in the ship’s wake; thank you, Matt, it was so incredibly cool! I definitely plan on taking him up on his offer for me to borrow the “Blue Planet” series to learn more about deep ocean luminescence.  So, brimming with curiosity and excitement, I look forward to the gentle rocking of the ship once I tumble into my bunk later this evening.

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Rachel Dane, May 2, 2005

NOAA Teacher at Sea
Rachel Dane
Onboard NOAA Ship Ka’imimoana
April 29 – May 10, 2005

Mission: Oceanographic Survey
Geographical Area: Puerto Ayora, Isla Santa Cruz, Galapagos
Date: May 2, 2005

Science and Technology Log

Today is the big day—my first day at sea! I am excited and nervous at the same time; with no experience sailing my main hope is that sea legs will develop quickly for me!  As Academy Bay receded behind us I was a bit wistful at having to leave the Galapagos with so much left unexplored, but I am phenomenally happy to have had the experience to travel here and truly hope to return someday.

Much of my afternoon was spent picking the brain of Patrick Rafter, our Ph.D. student from the Scripps Institution of Oceanography. Patrick boarded the KA in San Diego at the start of this cruise, and is amazingly knowledgeable about marine chemistry.  He is also super patient with all of my questions, and very fun to chat with! You rock, Patrick! I basically asked him for a crash course in oceanic interactions, and this is what he taught me—too cool!

Essentially, the ocean can be viewed as the shallow, warm “mixed layer” at the surface and the deep, cold ocean. The dividing line between these two is called the thermocline, and it is the level at which a rapid change in water temperature occurs. Think about it as a multi-layered cake, with each water layer maintaining a fairly unique and consistent salinity, density and water temperature.  Generally, the mixed layer at the surface is the warmest.  In the equatorial pacific this surface layer has a depth of about 100m, and it is this first layer of oceanic cake that NOAA is most interested in studying.  Normally, the thermocline that divides the high warm layer from the lower cold layer maintains a gradually increasing easterly slope.  Under normal conditions, there is also less convection occurring and less wind is present.  However, under El Nino conditions the dividing line between the two layers becomes more level, creating a deeper, warmer top layer. This increase in depth of the top layer affects marine interactions in several ways.  First, a much larger percentage of surface water is warmer.  Second, more convection is occurring due to the warmer water temperature, and third, more wind is present.  One of the major uncertainties that TAO project data is attempting to explain is the cause of this thermocline change.

Personal Log

After a long Monday and a fabulous shrimp dinner, I feel quite tired and ready to call it a day. Tomorrow, Joe will set up my ship email account; I am really looking forward to being in touch with friends and loved ones at home, and also communicating with my students! It pleases me to report that, surprisingly, my stomach feels more settled at sea then it did when we were anchored in the Bay!  I’m not feeling 100% yet, but definitely well enough to give the treadmill a try tomorrow—and maybe I can even skip the Dramamine… Until tomorrow!