Gregory Cook, The Dance, August 7, 2014

NOAA Teacher at Sea

Gregory Cook

Aboard NOAA Ship Oscar Dyson

July 26 – August 13, 2014

Mission: Annual Walleye Pollock Survey

Geographical Area: Bering Sea

Date: August 7, 2014

Science and Technology Log: Abiotic Factors in the Bering Sea

Ecosystems are made up of biotic and abiotic factors. Biotic is just another word for “stuff that is, or was, alive.” In a forest, that would include everything from Owl to Oak Tree, from bear to bacteria, and from fish to fungi. It includes anything alive, or, for that matter, dead. Keep in mind that “dead” is not the same as “non-living.”

Salmon and Black-Legged Kittiwake

The salmon and the black-legged kittiwake are both biotic members of the sub-arctic ecosystem.

“Non-living” describes things that are not, cannot, and never will be “alive.” These things are referred to as “abiotic.” (The prefix a- basically means the same as non-). Rocks, water, wind, sunlight and temperature are all considered abiotic factors. And while the most obvious threat to a salmon swimming up river might be the slash of a bear’s mighty claw, warm water could be even more deadly. Warm water carries less dissolved oxygen for the fish to absorb through their gills. This means that a power plant or factory that releases warm water into a river could actually cause fish to suffocate and, well, drown.

Bering Panorama

A 90 degree panorama of the Bering Sea from atop the Oscar Dyson. I’d show you the other 270°, but it’s pretty much the same. The sea and sky are abiotic parts of the sub-arctic ecosystem.

Fish in the Bering Sea have the same kind of challenges. Like Goldilocks, Pollock are always looking for sea water that is just right. The Oscar Dyson has the tools for testing all sorts of Abiotic factors. This is the Conductivity Temperature Depth sensor (Also known as the CTD).

CTD Deployment

Survey Technicians Allen and Bill teach me how to launch The Conductivity Temperature Depth Probe (or CTD).

The CTD sends signals up to computers in the cave to explain all sorts of abiotic conditions in the water column. It can measure how salty the water is by testing how well the water conducts electricity. It can tell you how cloudy, or turbid, the water is with a turbidity sensor. It can even tell you things like the amount of oxygen dissolved in the ocean.

To see how abiotic factors drive biotic factors, take a look at this.


The graph above is depth-oriented. The further down you go on the graph, the deeper in the water column you are. The blue line represents temperature. Does the temperature stay constant? Where does it change?

I know, you may want to turn the graph above on its side… but don’t. You’ll notice that depth is on the y-axis (left). That means that the further down you are on the graph, the deeper in the sea you are. The blue line represents the water temperature at that depth. Where do you see the temperature drop?

Right… The temperature drops rapidly between about 20 and 35 meters. This part of the water column is called the Thermocline, and you’ll find it in much of the world’s oceans. It’s essentially where the temperature between surface waters (which are heated by the sun) and the deeper waters (typically dark and cold) mix together.

OK, so you’re like “great. So what? Water gets colder. Big deal… let’s throw a parade for science.”

Well, look at the graph to the right. It was made from another kind of data recorded by the CTD.


Fluoresence: Another depth-oriented graph from the CTD… the green line effectively shows us the amount of phytoplankton in the water column, based on depth.

The green line represents the amount of fluorescence. Fluorescence is a marker of phytoplankton. Phytoplankton are plant-like protists… the great producers of the sea! The more fluorescence, the more phytoplankton you have. Phytoplankton love to live right at the bottom of the thermocline. It gives them the best of both worlds: sunlight from above and nutrients from the bottom of the sea, which so many animals call home.

Now, if you’re a fish… especially a vegetarian fish, you just said: “Dinner? I’m listening…” But there’s an added bonus.

Look at this:

CTD Oxygen

Oxygen data from the CTD! This shows where the most dissolved oxygen is in the water column, based on depth. Notice any connections to the other graphs?

That orange line represents the amount of oxygen dissolved in the water. How does that compare to the other graphs?

Yup! The phytoplankton is hanging down there at the bottom of the thermocline cranking out oxygen! What a fine place to be a fish! Dinner and plenty of fresh air to breathe! So here, the abiotic (the temperature) drives the biotic (phytoplankton) which then drives the abiotic again (oxygen). This dance between biotic and abiotic plays out throughout earth’s ecosystems.

Another major abiotic factor is the depth of the ocean floor. Deep areas, also known as abyss, or abyssal plains, have food sources that are so far below the surface that phytoplankton can’t take advantage of the ground nutrients. Bad for phytoplankton is, of course, bad for fish. Look at this:

The Cliff and the Cod

The blue cloud represents a last grouping of fish as the continental shelf drops into the deep. Dr. Mikhail examines a cod.

That sloping red line is the profile (side view of the shape of the land) of the ocean floor. Those blue dots on the slope are fish. As Dr. Mikhail Stepanenko, a visiting Pollock specialist from Vladivostok, Russia, puts it, “after this… no more Pollock. It’s too deep.”

He goes on to show me how Pollock in the Bering Sea are only found on the continental shelf between the Aleutian Islands and Northeastern Russia. Young Pollock start their lives down near the Aleutians to the southeast, then migrate Northwest towards Russia, where lots of food is waiting for them.

Pollock Distribution

Alaskan Pollock avoid the deep! Purple line represents the ocean floor right before it drops off into the Aleutian Basin… a very deep place!

The purple line drawn in represents the drop-off you saw above… right before the deep zone. Pollock tend to stay in the shallow areas above it… where the eating is good!

Once again, the dance between the abiotic and the biotic create an ecosystem. Over the abyss, Phytoplankton can’t take advantage of nutrients from the deep, and fish can’t take advantage of the phytoplankton. Nonliving aspects have a MASSIVE impact on all the organisms in an ecosystem.

Next time we explore the Biotic side of things… the Sub-arctic food web!

Personal Log: The Order of the Monkey’s Fist.

Sweet William, a retired police officer turned ship’s engineer, tells the story of the order of the monkey’s fist.

William and the Monkey's Fist

Sweet William the Engineer shows off a monkey’s fist

The story goes that some island came up with a clever way to catch monkeys. They’d place a piece of fruit in a jar just barely big enough for the fruit to fit through and then leave the jar out for the monkeys. When a monkey saw it, they’d reach their hand in to grab the fruit, but couldn’t pull it out because their hands were too big now that they had the fruit in it. The monkey, so attached to the idea of an “easy” meal wouldn’t let go, making them easy pickings for the islanders. The Monkey’s Fist became a symbol for how clinging to our desires for some things can, in the end, do more harm than good. That sometimes letting go of something we want so badly is, in the end, what can grant us relief.

Another story of the origin of the monkey’s fist goes like this: A sea captain saw a sailor on the beach sharing his meal with a monkey. Without skipping a beat, the monkey went into the jungle and brought the sailor some of HIS meal… a piece of fruit.

No man is an Island. Mt. Ballyhoo, Unalaska, AK

No man is an Island. Mt. Ballyhoo, Unalaska, AK

Whatever the true origin of the Order is, the message is the same. Generosity beats selfishness at sea. It’s often better to let go of your own interests, sometimes, and think of someone else’s. Onboard the Oscar Dyson, when we see someone committing an act of kindness, we put their name in a box. Every now and then they pull a name from the box, and that person wins something at the ship store… a hat or a t-shirt or what have you. Of course, that’s not the point. The point is that NOAA sailors… scientists, corps, and crew… have each other’s backs. They look out for each other in a place where all they really have IS each other.

And that’s a beautiful thing.

Sherie Gee: Male or Female? June 29, 2013

NOAA Teacher At Sea
Sherie Gee
Aboard the R/V Hugh R. Sharp
June 27 — July 7, 2013

Mission:  Sea Scallop Survey
Geographical Area of Cruise:  Northwest Atlantic Ocean
Date:  June 29, 2013 

Science and Technology Log:

Most of the shifts consisted of sorting out the animals from the dredges and carrying out the process of weighing, measuring and counting.  One other component to the process is that on every dredge, five of the scallops are scrubbed, weighed and dissected.  Once this is done, gender can be determined since this species of sea scallops have separate sexes.  Then each scallop is numbered, labeled, tagged, and bagged.  These five sea scallops will be brought back to the lab on land to be analyzed and aged.  This is done by counting growth rings on the shell.   The part of the scallop that is used as food is not the actual animal but the adductor muscle that is located in the middle of the shell.  This is the muscle that can open and close the scallop’s shell.  This is the only bivalve to be motile.  Often times other organisms find a nice little resting spot inside of the shells of the scallops.  This is a form of commensalism where the organism benefits while not harming the host.  We saw a small red hake living inside the shell of a dissected sea scallop.

The Atlantic Sea Scallop

The Atlantic Sea Scallop

After every other dredge, the crew brings out the CTD which is an apparatus that collects conductivity, temperature, and depth.  This data enters the database and is used in the labs on shore.  We could always tell when they were lowering the CTD because the ship had to come to a complete stop while collecting data.  Then they would bring the CTD back in and the ship would resume forward.

The CTD - Conductivity, Temperature and Depth

The CTD – Conductivity, Temperature and Depth

Did you Know:

The male sea scallop’s gonad is white and the female’s gonad is red.  Gonads are reproductive organs.

Personal Log:

I learned the secret to gearing up efficiently with the boots and foul weather overalls from Larry.  When you are ready to take them off, pull the overall part down toward the boots and leave about an inch of the boots exposed. Then just step out of the boots into regular shoes.  I’m glad I brought some slip-on shoes which made things a lot easier.  Then when it is time to gear up again, all I had to do was slip back into the boots and pull up the pants and suspenders.  We also had to wear rubber work gloves that kept us from cutting ourselves during the dredges.

Boots and Foul Weather Gear

Boots and Foul Weather Gear

I interviewed our steward, Lee, for one of my requirements by NOAA. I found her to be a very interesting and social person.  She is also the cook so she takes on two responsibilities at one time. She has to plan the meals, cook the meals and clean up after the meals. In addition to taking care of all kitchen duties, she also has to clean the heads (bathrooms), vacuum the carpets, clean the staterooms and do the laundry. She had to take some extensive courses on basic safety training for commercial vessels. Her satisfaction to the job is making food that people like and keeping up morale on the ship.  She has a designated drawer which serves as a treasure chest of gold only the gold is actually tons of candy. All kinds of candy.  She also keeps one big freezer full of ice cream and a refrigerator full of most types of can sodas.

Lee's Shrimp Jambalaya

Lee’s Shrimp Jambalaya

The Ship's Treasure

The Ship’s Treasure

Lee- The Ship's Cook and Steward

Lee- The Ship’s Cook and Steward

Steven Wilkie: June 26, 2011

JUNE 23 — JULY 4, 2011

Mission: Summer Groundfish Survey
Geographic Location: Northern Gulf of Mexico
Date: June 26, 2011

Ship Data:

Latitude 26.56
Longitude -96.41
Speed 10.00 kts
Course 6.00
Wind Speed 4.55 kts
Wind Dir. 150.72 º
Surf. Water Temp. 28.30 ºC
Surf. Water Sal. 24.88 PSU
Air Temperature 29.20 ºC
Relative Humidity 78.00 %
Barometric Pres. 1012.27 mb
Water Depth 115.20 m

Before getting down to work, it is important to learn all precautionary measures. Here I am suited up in a survival suit during an abandon ship drill.

Science and Technology Log

After two days of travel we are on site and beginning to work and I believe the entire crew is eager to get their hands busy, myself included.   As I mentioned in my previous post, it is difficult if not impossible to separate the abiotic factors from the biotic factors, and as a result it is important to monitor the abiotic factors prior to every trawl event.  The main piece of equipment involved in monitoring the water quality (an abiotic factor) is the C-T-D (Conductivity, Temperature and Depth) device.  This device uses sophisticated sensors to determine the conductivity of the water, which in turn, can be used to measure salinity (differing salinities will conduct electricity at different rates).   Salinity influences the density of the water: the saltier the water the more dense the water is.  Density measures the amount of mass in a specific volume, so if you dissolve salt in a glass of water you are adding more mass without much volume.  And since Density=Mass/Volume, the more salt you add, the denser the water will get.   Less dense objects tend to float higher in the water column than more dense objects, so as a result the ocean often has layers of differing salinities (less salty water on top of more salty water).  Often you encounter a boundary between the two layers known as a halocline (see the graph below for evidence of a halocline).

Temperature varies with depth in the ocean, however, because warm water is less dense than cold water. When liquids are cold, more molecules can fit into a space than when they are war; therefore there is more mass in that volume.   The warm water tends to remain towards the surface, while the cooler water remains at depth.  You may have experienced this if you swim in a local lake or river.  You dive down and all of a sudden the water goes from nice and warm to cool. This is known as a thermocline and is the result of the warm, less dense water sitting on top of the cool more dense water.

Here is the fancy piece of technology that makes measuring water quality so easy: the CTD.

Temperature also influences the amount of oxygen that water can hold. The cooler the temperature of the water the more oxygen can dissolve in it.  This is yet another reason why the hypoxic zones discussed in my last blog are more common in summer months than winter months: the warm water simply does not hold as much oxygen as it does in the winter.

The CTD is also capable of measuring chlorophyll.  Chlorophyll is a molecule that photosynthetic organisms use to capture light energy and then use to build complex organic molecules that they can in turn be used as energy to grow, reproduce etc.  The more chlorophyll in the water, the more photosynthetic phytoplankton there is in the water column.  This can be a good thing, since photosynthetic organisms are the foundation of the food chain, but as I mentioned in my earlier blog, too much phytoplankton can also lead to hypoxic zones.

Finally the CTD sensor is capable of measuring the water’s turbidity.  This measures how clear the water is.  Think of water around a coral reef — that water has a very low turbidity, so you can see quite a ways into the water (which is good for coral since they need access to sunlight to survive).  Water in estuaries or near shore is often quite turbid because of all of the run off coming from land.

This is a CTD data sample taken on June 26th at a depth of 94 meters. The pink line represents chlorophyll concentration, the green represents oxygen concentration, the blue is temperature and the red is salinity.

So, that is how we measure the abiotic factors, now let’s concentrate on how we measure the biotic!  After using the CTD (and it takes less time to use it than it does to describe it here) we are ready to pull our trawls.  There are three different trawls that the scientists rely on and they each focus on different “groups” of organisms.

The neuston net captures organisms living just at the water's surface.

The neuston net (named for the neuston zone, which is where the surface of the water interacts with the atmosphere) is pulled along the side of the ship and skims the surface of the water.  At the end of the net is a small “catch bottle” that will capture anything bigger than .947 microns.  The bongo nets are nets that are targeting organisms of a similar size, but instead of remaining at the surface these nets are lowered from the surface to the seafloor and back again, capturing a representative sample of organisms throughout the water column.   The neuston net is towed for approximately ten minutes, while the bongo nets tow times are dependent on depth.   Once the nets are brought in, the scientists, myself included, take the catch and preserve it for the scientists back in the lab to study.

The bongo nets will capture organisms from the surface all the way down to bottom.

The biggest and baddest nets on the boat are the actual trawl nets launched from the stern (back) of the boat.  These are the nets the scientists are relying on to target the bottom fish.  This trawl net is often referred to as an otter trawl because of the giant heavy doors used to pull the mouth of the net open once it reaches the bottom.  As the boat moves forward, a “tickler” chain spooks any of the organisms that might be lounging around on the bottom and the net follows behind to scoop them up.  This net is towed for thirty minutes, and then retrieved and we spend the next hour or so sorting, counting and measuring the catch.

Here you can see the otter trawl net extending off the starboard side of the Oregon II. When lowered into the water the doors will spread the mouth of the net.

Personal Log
I thought that adjusting to a 12 hour work schedule would be tough, but with a 5-month old son at home I feel I am more prepared than most might be for an extended day.  I might go as far as to say that I have more down time now than I did at home!  Although the ship’s crew actually manages the deployment of the majority of the nets and C-T-D, the science team is always involved and keeping busy allows the hours to tick away without much thought.  Before you know it you are on the stern deck of the ship staring at a gorgeous Gulf of Mexico sunset.

As we steam back East, the sun sets in our stern every day, and we have been treated to peaceful ones thus far on this trip.

The sun has long since set.  As I write this it is well after midnight and my bunk is calling.

Christine Hedge, September 15, 2009

NOAA Teacher at Sea
Christine Hedge
Onboard USCGC Healy
August 7 – September 16, 2009 

Mission: U.S.-Canada 2009 Arctic Seafloor Continental Shelf Survey
Location: Chukchi Sea, north of the arctic circle
Date: September 15, 2009

MST2 Tom Kruger and MST3 Marshall Chaidez retrieve a meteorological buoy on September 14.

MST2 Tom Kruger and MST3 Marshall Chaidez retrieve a meteorological buoy on September 14.

Weather Data from the Bridge 
Latitude: 730 22’N
Longitude: 1560 27’W
Temperature: 310F

Science and Technology Log 

The past few days have brought much change.  The depth of the ocean changed dramatically as we got closer to Alaska. The ocean went from depths of over 3500 meters to depths of less than 100 meters.  More birds are showing up and we are getting about 9 hours of darkness each day.  This morning at about 4 AM, the watch observed the Aurora Borealis and stars!!!  I am so jealous.

FOR MY STUDENTS: Why do you think we have more hours of darkness now? 

As we head home to Barrow, the science party is busily completing their “Cruise Reports” and making sure that their data is stored safely for the trip home.  Much has been accomplished on this trip:

  • 132 XBT deployments (measures temperature, depth)
  • 8 CTD deployments (measures conductivity, temperature, depth)
  • 5 Dredge operations and hundreds of pounds of rock samples collected and catalogued
  •  1 Seaglider deployed and retrieved
  • 2 HARP instruments retrieved and 3 deployed
  • 3 Ice buoys deployed
  • 8 Sonobuoys deployed
  • 9585.0 lineal kilometers of sea floor mapped
  • 1 METBUOY retrieved (meteorological buoy)

Coast Guard Marine Science Technicians  

MST3 Marshal Chaidez operates the winch during a dredging operation.

MST3 Marshal Chaidez operates the winch during a dredging operation.

Science parties come and go on the Healy, each doing a different type of research.  A constant for all the scientific cruises is the good work done by the Coast Guard MSTs (Marine Science Technicians). Running the winch, taking daily XBT and weather measurements, working the dredge, and helping to deploy buoys are just some of the many tasks these technicians do. The scientists could not get their experiments done without the assistance of our team of MSTs.

MST3 Daniel Purse, MST2 Daniel Jarrett, MST3 Marshal Chaidez, MST2 Thomas Kruger and Chief Mark Rieg have done a masterful job of helping the science party accomplish their goals. I asked them to tell me a little about their training for this job. Each MST attends a 10-week training school in Yorktown, VA. Most of their training involves how to clean up oil spills and inspect cargo ships which means they are usually stationed at a port. Being assigned to a ship is not the norm for an MST.  But, because the mission of the Healy is specifically science, a team of MSTs is essential.

MST2 Daniel Jarrett rigging the crane.

MST2 Daniel Jarrett rigging the crane.

Personal Log 

My commute to work is different lately. We have about 9 hours of darkness each day. It gets dark around midnight and stays dark until about 8:30 in the morning.  So, walking the deck to the science lab is a bit of a challenge at 7:45. It will be strange to drive to work in a few days! On September 16th, we will depart the Healy via helicopter if all goes according to plan.  It will be strange to be on land again.

We will be back in Barrow, AK on September 16th. I cannot believe that our expedition is almost over.  I have learned so much from the members of the science party and the crew of the Healy. They have been very gracious and patient while I took their pictures and asked questions. Now comes the task of sharing what I have learned with folks back home.  I know one thing for sure; the Arctic is no longer an abstract idea for me. It is a place of beauty and mystery and a place some people call home.  I hope to convey how important it is that we continue to study this place to learn how it came to be and how it is currently changing.

Jon Pazol and I next to the bowhead whale skull in Barrow. When we return to shore the bowhead hunting season will have started.

Jon Pazol and I next to the bowhead whale skull in Barrow. When we return to shore the bowhead hunting season will have started.

Thanks to the folks at NOAA Teacher at Sea, Captain Sommer, and chief scientists Larry Mayer and Andy Armstrong for allowing me to take part in this cruise.  You can be sure that I will be following Arctic research and the adventures of the Healy for many years to come.

Christine Hedge, August 25, 2009

NOAA Teacher at Sea
Christine Hedge
Onboard USCGC Healy
August 7 – September 16, 2009 

Mission: U.S.-Canada 2009 Arctic Seafloor Continental Shelf Survey
Location: Beaufort Sea, north of the arctic circle
Date: August 25, 2009

Weather Data from the Bridge 
Temperature: 30.150F
Latitude: 81.310 N
Longitude: 134.280W

Science and Technology Log 

This multibeam image of the new seamount is what I saw in the Science Lab.

This multibeam image of the new seamount is what I saw in the Science Lab.

A Day of Discovery… 

Today, our planned route took us near an unmapped feature on the sea floor.  A 2002 Russian contour map showed a single contour (a bump in the middle of a flat plain) at 3600 meters.  This single contour line also appeared on the IBCAO (International Bathymetric Chart of the Arctic Ocean) map.  We were so close that we decided to take a slight detour and see if there really was a bump on this flat, featureless stretch of sea floor. 

The contour was labeled 3600 meters and the sea floor in the area averaged about 3800 meters so a 200 meter bump was what the map suggested.  As the Healy traveled over the area we found much more than a bump!  The feature slowly unfolded before our eyes on the computer screen.  It got taller and taller and excitement grew as people realized this might be over 1000 meters tall.  If a feature is 1000 meters or more, it is considered a seamount (underwater mountain) and can be named.  Finally, the picture was complete, the data was processed, and a new seamount was discovered. The height is approximately 1,100 meters and the location is 81.31.57N and 134.28.80W.

The colors on this 3-D image of the newly discovered seamount indicate depth.

The colors on this 3-D image of the newly discovered seamount indicate depth.

Why Isn’t the Arctic Mapped? 

Some areas of the sea floor have been mapped and charted over and over again with each improvement in our bathymetric technology.  Areas with lots of ship traffic such as San Francisco Bay or Chesapeake Bay need to have excellent bathymetric charts, which show depth of the water, and any features on the sea floor that might cause damage to a ship.  But in the Arctic Ocean, there isn’t much ship traffic and it is a difficult place to collect bathymetric data because of all the ice. Therefore, in some areas the maps are based on very sparse soundings from lots of different sources. Remember, older maps are often based on data that was collected before multibeam  echosounders and GPS navigation – new technology means more precise data!  

Personal Log 

This is the IBCAO.  (International Bathymetric chart of the Arctic Ocean)  It is a great resource for ships exploring the Arctic Basin.

This is the IBCAO. (International Bathymetric chart of the Arctic Ocean) It is a great resource for ships exploring the Arctic Basin.

It is still very foggy. We are about 625 miles north of Alaska and plowing through ice that is 1-2 meters thick.  This time of year it is the melt season.  Increased evaporation means more water in the atmosphere and more fog.  Even though we are usually in water that is 90% covered by ice (REMEMBER 9/10 ice cover?) we rarely have to back and ram to get through.  It is noisier lately and the chunks of ice that pop up beside the ship are more interesting to look at.  There are blue stripes, brown patches of algae and usually a thin layer of snow on top.

I cannot send a current sound file because of our limited bandwidth on the Healy. When we are this far north it is difficult to get Internet access. But, if you would like to hear what it sounds like when the Healy is breaking ice, click on this link  from a past trip through Arctic sea ice.

Sea Ice at 810N after the Healy has broken through

Sea Ice after the Healy has broken through

Patricia Schromen, August 22, 2009

NOAA Teacher at Sea
Patricia Schromen
Onboard NOAA Ship Miller Freeman
August 19-24, 2009 

Mission: Hake Survey
Geographical Area: Northwest Pacific Coast
Date: Thursday, August 22, 2009

Bringing in the nets requires attention, strength and teamwork.

Bringing in the nets requires attention and teamwork.

Weather Data from the Bridge 
SW wind 10 knots
Wind waves 1 or 2 feet
17 degrees Celsius

Science and Technology Log 

In Science we learn that a system consists of many parts working together. This ship is a small integrated system-many teams working together. Each team is accountable for their part of the hake survey. Like any good science investigation there are independent, dependent and controlled variables. There are so many variables involved just to determine where and when to take a fish sample.

Matt directs the crane to move to the right. Looks like some extra squid ink in this haul.

Matt directs the crane to move to the right. Looks like some extra squid ink in this haul.

The acoustic scientists constantly monitor sonar images in the acoustics lab. There are ten screens displaying different information in that one room. The skilled scientists decide when it is time to fish by analyzing the data.  Different species have different acoustical signatures. Some screens show echograms of marine organisms detected in the water column by the echo sounders. With these echograms, the scientists have become very accurate in predicting what will likely be caught in the net. The OOD (Officer of the Deck) is responsible for driving the ship and observes different data from the bridge. Some of the variables they monitor are weather related; for example: wind speed and direction or swell height and period. Other variables are observed on radar like the other ships in the area. The topography of the ocean floor is also critical when nets are lowered to collect bottom fish. There are numerous sophisticated instruments on the bridge collecting information twenty four hours a day. Well trained officers analyze this data constantly to keep the ship on a safe course.

Here come the hake!

Here come the hake!

When the decision to fish has been made more variables are involved. One person must watch for marine mammals for at least 10 minutes prior to fishing. If marine mammals are present in this area then they cannot be disturbed and the scientists will have to delay fishing until the marine mammals leave or find another location to fish. When the nets are deployed the speed of the boat, the tension on the winch, the amount of weight attached will determine how fast the nets reach their target fishing depth.  In the small trawl house facing the stern of the ship where the trawl nets are deployed, a variety of net monitoring instruments and the echo sounder are watched. The ship personnel are communicating with the bridge; the deck crew are controlling the winches and net reels and the acoustic scientist is determining exactly how deep and the duration of the trawl. Data is constantly being recorded. There are many decisions that must be made quickly involving numerous variables.

Working together to sort the squid from the hake.

Working together to sort the squid from the hake.

The Hake Survey began in 1977 collecting every three years and then in 2001 it became a biannual survey. Like all experiments there are protocols that must be followed to ensure data quality. Protocols define survey operations from sunrise to sunset. Survey transect line design is also included in the protocols. The US portion of the Hake survey is from approximately 60 nautical miles south of Monterey, California to the US-Canada Border. The exact location of the fishing samples changes based on fish detected in the echograms although the distance between transects is fished at 10 nautical miles. Covering depths of 50-1500 m throughout the survey. Sampling one species to determine the health of fish populations and ocean trends is very dynamic.

Weighing and measuring the hake is easier with automated scales and length boards.

Weighing and measuring the hake.

Personal Log 

Science requires team work and accountability. Every crew member has an integral part in making this survey accurate.  A willing positive attitude and ability to perform your best is consistently evident on the Miller Freeman. In the past few days, I’ve had the amazing opportunity to assist in collecting the data of most of the parts of this survey, even launching the CTD at night from the “Hero Platform” an extended grate from the quarter deck.

Stomach samples need to be accurately labeled and handled carefully.

Stomach samples need to be accurately labeled and handled carefully.

Before fishing, I’ve been on the bridge looking for marine mammals.  When the fish nets have been recovered and dumped on the sorting table, I’ve sorted, weighed and measured fish. For my first experience in the wet lab, I was pleased to be asked to scan numbers (a relatively clean task) and put otoliths (ear bones) into vials of alcohol. I used forceps instead of a scalpel. Ten stomachs are dissected, placed in cloth bags and preserved in formaldehyde. A label goes into each cloth bag so that the specimen can be cross referenced with the otoliths, weight, length and sex of that hake. With all the high tech equipment it’s surprising that a lowly pencil is the necessary tool but the paper is high tech since it looks regular but is water proof.  It was special to record the 100th catch of the survey.

Removing the otolith (ear bone) with one exact incision. An otolith reminds me of a squash seed or a little silver feather in jewelry.

Removing the otolith (ear bone) with one exact incision. An otolith reminds me of a squash seed or a little silver feather in jewelry.

Each barcoded vial is scanned so the otolith number is linked to the weight, length and sex data of the individual hake.

Each barcoded vial is scanned so the otolith number is linked to the weight, length and sex data of the individual hake.

Questions for the Day 

How is a fish ear bone (otolith) similar to a tree trunk? (They both have rings that can be counted as a way to determine the age of the fish or the tree.)

The CTD (conductivity, temperature and depth) unit drops 60 meters per minute and the ocean is 425 meters deep at this location; how many minutes will it take the CTD to reach the 420 meter depth?

Think About This: The survey team directs the crane operator to stop the CTD drop within 5 meters of the bottom of the ocean.  Can you think of reasons why the delicate machinery is never dropped exactly to the ocean floor?  Some possible reasons are:

  • The swell in the ocean could make the ship higher at that moment;
  • An object that is not detected on the sonar could be on the ocean floor;
  • The rosetta or carousel holding the measurement tools might not be level.

Launching the CTD is a cooperative effort. The boom operator works from the deck above in visual contact. Everyone is in radio contact with the bridge since the ship slows down for this data collection.

Retrieving the CTD

Retrieving the CTD

Christine Hedge, August 20, 2009

NOAA Teacher at Sea
Christine Hedge
Onboard USCGC Healy
August 7 – September 16, 2009 

Mission: U.S.-Canada 2009 Arctic Seafloor Continental Shelf Survey
Location: Beaufort Sea, north of the arctic circle
Date: August 20, 2009

Weather Data from the Bridge  
Lat: 80.570 N
Long: 151.320 W
Air Temp: 29.210 F

Science and Technology Log 

The science computer lab is where the data is observed. Processors clean the data of all the extraneous noise and spikes. Not every beam is returned and some take a bad bounce off a fish, chunk of ice or a bubble.

The science computer lab is where the data is observed. Processors clean the data of all the extraneous noise and spikes. Not every beam is returned and some take a bad bounce off a fish, chunk of ice or a bubble.

The Healy is collecting bathymetric data on this trip.  Bathymetric data will tell us how deep the ocean is and what the terrain of the ocean floor is like.  Less than 6% of the floor of the Arctic Ocean has been mapped.  So, this data will help us to learn about some places for the very first time.  The word bathymetry comes from the Greek – bathy= deep and metry = to measure.

NOTE TO STUDENTS: If you learn Latin/Greek word parts you can understand almost any word! 

How Do We Collect This Data? 

There are two main devices the Healy is using to measure the depth to the seafloor.  One is called the multibeam echosounder. It sends a beam of sound, which reflects off the bottom and sends back up to 121 beams to a receiver. By measuring the time it takes for the sound to return the multibeam can accurately map the surface of the sea floor.  This allows the multibeam to “see” a wide swath of seafloor – kilometers wide.  The other device is bouncing a single beam off the bottom and “seeing” a profile of that spot. This one is called a single beam echosounder or sub-bottom profiler. The single beam actually penetrates the sea floor to show a cross-section of the layers of sediment. Both are mounted on the hull of the ship and send their data and images to computers in the science lab.

What Does Mrs. Hedge Do? 

This screen shows the multibeam bathymetry data.  Depth is measured over a swath about 8 kilometers wide on this particular screen.  Purple is the deepest (3850 m) and orange is the most shallow (3000 m).  You can see that for most of this trip we were on flat abyssal plain and then we hit a little bump on the sea floor about 450 meters tall.

This screen shows the multibeam bathymetry data. Depth is measured over a swath about 8 kilometers wide on this particular screen. Purple is the deepest (3850 m) and orange is the most shallow (3000 m). You can see that for most of this trip we were on flat abyssal plain and then we hit a little bump on the sea floor about 450 meters tall.

The science crew takes turns “standing watch”. We have 3 teams; each watches the computers that display the bathymetry data for an 8-hour shift. My watch is from 8 am until 4 pm.  We need to look at how many beams are being received and sometimes make adjustments.  Traveling through heavy ice makes data collection challenging. We also need to “log” or record anything that might impact the data collection such the ship turning, stopping, heavy ice, or a change in speed. When we are going over an interesting feature on the seafloor, our job is engaging. When the seafloor is flat, the 8-hour shift can seem pretty long!

How Did People Do This Before Computers? 

Until the 1930’s, the depth of the ocean was taken by lowering a lead weight on a heavy rope over the side of a boat and measuring how much rope it took until the weight hit the bottom. This was called a lead line.  Then the boat would move and do this again, over and over.

Another bear was spotted from the Healy. Photo Pat Kelley.

Another bear was spotted from the Healy. Photo Pat Kelley.

This method was very time consuming because it only measured depth at one point in time.    Between soundings, people would just infer what the depth was.  Using sound to measure depth is a huge improvement compared to soundings with a weighted rope.  For example, in 100 meters of water, with a lead line 10 soundings per hour could be obtained.  With multibeam at the same depth, 1,500,000 soundings can be obtained per hour.  Mapping the ocean floor has become much more accurate and precise.

FOR MY STUDENTS: Can you think of other areas of science where improvements in technology lead to huge improvements and new discoveries? 

Personal Log 

When a polar bear is spotted, the deck fills with hopeful observers.

When a polar bear is spotted, the deck fills with hopeful observers.

Last night, there was an announcement right after I went to bed that polar bears had been spotted.  I threw on some clothes and ran outside.  There was a female and cub 2 kilometers away.  With binoculars, I could see them pretty well.  The adult kept turning around and looking at the cub over her shoulder. I suspect, the cub was being told to hurry up!  When a bear is spotted, the deck of the ship fills up with hopeful observers no matter what time of day it is.

FOR MY STUDENTS: I heard that the old polar bear at the Indianapolis Zoo died recently. Will there still be a polar bear exhibit at the zoo?  What are the plans for the future?