Melissa George: Do You Hear What I Hear? July 28, 2013

NOAA Teacher at Sea
Melissa George
Aboard NOAA Ship Oscar Dyson
July 22 – August 9, 2013

Mission:  Pollock Survey
Geographical Area of Cruise:  Gulf of Alaska
Date:  Sunday, July 28, 2013

Current Data From Today’s Cruise

Weather Data from the Bridge 
Sky Condition:  Cloudy
Temperature:  14° C
Wind Speed:  4 knots
Barometric Pressure:  1025.1 mb
Humidity:  90%

Sun and Moon Data 
Sunrise:  5:57 am
Sunset:  10:34 pm

Moonrise:  11:52 pm  (July 27, 2013)
Moonset:  2:35 pm

Geographic Coordinates at 

Latitude:  59° 53.3′ N
Longitude:  149° 00.0′ W

The ship’s position now can be found by clicking:  Oscar Dyson’s Geographical Position

False Point on Kenai Peninsula (viewed this morning through the fog)

False Point on Kenai Peninsula (viewed this morning through the fog)

Science and Technology Log

How do scientists use acoustics to locate Pollock (and serendipitously other ocean creatures)?

Scientists aboard the NOAA Research Vessel Oscar Dyson use acoustic, specifically hydroacoustic data, to locate schools of fish before trawling.  The trawl data provide a sample from each school and allow the NOAA scientists to take a closer look by age, gender and species distribution.  Basically, the trawl data verify and validate the acoustics data.  The acoustics data, collected in the Gulf of Alaska in systematic paths called transects, combined with the validating biological data from the numerous individual trawls, give scientists a very good estimate for the entire Walleye pollock population in this location.

This screen is showing the echogram from the EK 60 echosounder during a trawl at 83.13 meters.  The red line in the middle of the screen is the ocean floor.  The colorful spikes above the red line indicate “backscatter” that is characteristic of capelin, a small fish that pollock feed on.

This screen is showing the echogram from the EK 60 echosounder during a trawl at 83.13 meters. The red line in the middle of the screen is the ocean floor. The colorful spikes above the red line indicate “backscatter” that is characteristic of capelin, a small fish that pollock feed on.

Hydroacoustics  (from Greek words: hydro meaning “water”  and  acoustics meaning “sound”) is the study of sound in water.  Sound is a form of energy that travels in pressure waves. In water, sound can travel great distances without losing strength and can travel fast, roughly 4.3 times faster in water than in air (depending on temperature and salinity of the water).

Click on this picture to see how sound travels from various ocean creatures through water. (Photo from sciencelearn.org)

Click on this picture to see how sound travels from various ocean creatures through water. (Photo from sciencelearn.org)

The Oscar Dyson has powerful, extremely sensitive, carefully calibrated, scientific acoustic instruments or “fish finders” including the five SIMRAD EK60 transducers located on the bottom of the centerboard, the SIMRAD ME70 multibeam transducer located on the hull, and a pair of SIMRAD ITI transducers on the trailing edge of the centerboard.

Image of acoustic instruments on the Oscar Dyson.  (Photo courtesy of NOAA Teacher at Sea Program)

Image of acoustic instruments on the Oscar Dyson. (Photo courtesy of NOAA Teacher at Sea Program)

This “fish-finder” technology works when transducers emit a sound wave at a particular frequency and detect the sound wave bouncing back (the echo) at the same frequency.  When the sound waves return from a school of fish, the strength of the returning echo helps determine how many fish are at that particular site.

The green ship’s transducer is sending out sound waves towards the fish.  The waves bounce back echoes towards the ship that are received by the transducer.  (Photo courtesy of Oracle Thinkquest)

The green ship’s transducer is sending out sound waves towards the fish. The waves bounce back echoes towards the ship that are received by the transducer. (Photo courtesy of Oracle Thinkquest)

Sound waves bounce or reflect off of fish and other creatures in the sea differently.  Most fish reflect sound energy sent from the transducers because of their swim bladders, organs that fish use to stay buoyant in the water column.  Since a swim bladder is filled with air, it reflects sound very well.   When the sound energy goes from one medium to another, there is a stronger reflection of that sound energy.  In most cases, the bigger the fish, the bigger the swim bladder; the bigger the swim bladder, the more sound is reflected and received by the transducer.  The characteristic reflection of sound is called target strength and can be used to detect the size of the fish. This is why fish that have air-filled swim bladders show up nicely on hydroacoustic data, while fish that lack swim bladders (like sharks) or that have oil or wax filled swim bladders (like Orange Roughy), have weak signals.

The above picture shows the location of the swim bladder.  (Photo courtesy of greatneck.k12.ny.us)

The above picture shows the location of the swim bladder. (Photo courtesy of greatneck.k12.ny.us)

These reflections of sound (echoes) are sent to computers which display the information in echograms.  The reflections showing up on the computer screen are called backscatter.  The backscatter is how we determine how dense the fish are in a particular school.  Scientists take the backscatter that we measure from the transducers and divide that by the target strength for an individual and that gives  the number of individuals that must be there to produce that amount of backscatter.  For example, a hundred fish produce 100x more echoes than a single fish.  This information can be used to estimate the pollock population in the Gulf of Alaska.

The above picture shows a computer screen with dense red “backscatter” characteristic of large amount of fish. The yellow lines above and below the backscatter show the location of the trawl lines.

The above picture shows a computer screen with dense red “backscatter” characteristic of large amount of fish, most likely pollock. The yellow lines above and below the backscatter show the location of the trawl lines.

Personal Log: 

Safety

Safety Announcements Don the Walls of the Oscar Dyson

Safety Announcements Don the Walls of the Oscar Dyson

Continuing with Maslow’s hierarchy of needs, I will continue up the pyramid  (see below) and discuss some ways that the basic need of safety is  met on the ship.  The safety and security of all staff (as well as sea animals we encounter) are top priority on the Oscar Dyson.   There are constant reminders of  this priority during ship life.
A Version of Maslow's Hierarchy of Needs

A Version of Maslow’s Hierarchy of Needs

Safety Drills

On the first day of our travel,  before the Oscar Dyson was far from port at Kodiak,  we had three drills.  The fire drill and man overboard drill required me to report to the conference room and meet up with the rest of the science team.  Patrick, the lead scientist, then reported that we (the scientist team) were all accounted for.  The crew had more complex tasks of deploying a small boat and retrieving “the man overboard”.

The other drill was the abandon ship drill.  On the ship, every person is assigned to a life boat (mine is Lifeboat 1).  When the drill commenced, I reported to my muster, the portside of the trawl deck, with survival gear:  jacket, hat, survival suit and life preserver.  We will have drills weekly at anytime.

Abandon Ship Crew Assignments

Abandon Ship Crew Assignments

Safety Gear
When working in the lab, the scientists wear orange slickers, boots, and gloves, not only to keep clean, but to protect us from anything that might be dangerous (fish spines, jellyfish tentacles, and so on).  When on deck, we must wear hardhats (to protect from falling objects from the crane or trawl) and life preservers like the rest of the crew.
Gloves, a Must in Fish Lab!

Gloves, a Must in Fish Lab!

Water Tight Doors
Watertight doors are special types of doors found on the ship which prevent the flow of water from one compartment to other during flooding or accidents. These doors are used onboard in areas, such as the engine room compartment,  science and acoustics labs, and control bridge, where chances of flooding are high.
Water Tight Door on Bridge

Water Tight Door on Bridge

These are just a few examples of how safety is emphasized on the ship.  There are reminders in one’s line of vision constantly.
Safety, Everyone's Responsibility

Safety, Everyone’s Responsibility

Did You Know?

There are various seafarer or crew positions on the Oscar Dyson.  A ship’s crew can generally be divided into three main categories: the deck department, the engineering department, and the steward department.  Rob and Greg are members of the deck department; both men hold Merchant Mariner Credentials as “Able Bodied Seamen” or ABS.  Rob is from Boston, Massachusetts and went to school for seamanship in Fairhaven, MA.  He considers his NOAA position as a good job with a good income, but his main profession is lobstering which he does on the open sea when he is not working for NOAA.  Rob says, “The ocean is in my blood” and always wanted to work on it.   Greg, on the other hand, chose to be a Merchant Mariner after a voyage at sea.  He moved to Texas from Louisiana in his 20’s, went fishing for the first time, and got seasick.  He considered battling seasickness a challenge, and thus pursing seamanship as a career.  In his free time he is a free-lance photographer and journalist.  Below are some pictures of Greg and Rob on the job.  Notice they are always wearing their safety gear.
Greg and Rob Bringing in the Trawling Net

Greg and Rob Bringing in the Trawling Net

Greg and Rob, Preparing for a Camera Drop

Greg and Rob, Preparing for a Camera Drop

Something to Think About: 

Since I will begin teaching Zoology later in August, I have decided to highlight some of the animals that the scientist team has found in our trawls.  Today’s feature will be one of the simplest multicellular animal families, the Porifera.  Porifera is a word formed from combining the Latin words porus which means “passage-way” and fera meaning “bearing.”  Porifera, commonly referred to as sponges, have tiny pores in their outer walls that filter water to get nutrients.  

Various Porifera (Sponges) from a Bottom Trawl

Various Porifera (Sponges) from a Bottom Trawl

Teacher (me) Demonstrating How Water Flows out the Osculum (opening) of a Poriferan

Teacher (me) Demonstrating How Water Flows out the Osculum (opening) of a Poriferan

To learn more about the Porifera Family, click the Porifera on the picture below, and stay tuned for further exploration of this animal Tree of Life.

Tree of Life:  Can you spot  the Poriferan?

Tree of Life: Can you spot the Poriferan?

Melissa George: Crossing the Line, July 25, 2013

NOAA Teacher at Sea
Melissa George
Aboard NOAA Ship Oscar Dyson
July 22 – August 9, 2013

Mission:  Pollock Survey
Geographical Area of Cruise:  Gulf of Alaska
Date:  Thursday, July 25, 2013

Current Data From Today’s Cruise 

Weather Data from the Bridge (at 6:00 am Alaska Daylight Time)
Sky Condition:  Fog
Temperature:  12° C
Wind Speed:  11 knots
Barometric Pressure:  1017.5 mb
Humidity:  87%

Sun and Moon Data
Sunrise:  5:51 am
Sunset:  10:40 pm

Moonrise:  10:57 pm (July 24, 2013)
Moonset:  10:37 am

Geographic Coordinates (at 6:00 am Alaska Daylight Time)
Latitude:  58° 30.5′ N
Longitude: 148° 47.7′ W

The ship’s position now can be found by clicking:

Oscar Dyson’s Geographical Position

Science and Technology Log

How can you determine the population size of species?  You could count every member of the population.  This would be the most accurate method, but what if the individuals in the population move around a lot? What if the population is enormous and requires too much time to count each individual?   For example, krill is a small crustacean (usually between 1 and 6 cm long) that accounts for 400-500 million metric tons of biomass in the world’s oceans.  Would you want to count all of the krill in the Gulf of Alaska?

Krill (and a Few Capelin)

Krill (and a Few Capelin)

Often, ocean populations of animals are just too large to count.  Sampling, or collecting a manageable subset of the population and using the information gathered from it to make inferences about the entire population, is a technique that ocean scientists use.   There are a variety of ways to sample.

One method is called mark and recapture.   In this method,  one catches individuals from the population, tags them, and releases them in a certain area.  After a set amount of time, an attempt is made to recapture individuals.  Data are compiled from the recaptures and the population is mathematically calculated.  Tuna populations in some areas are monitored this way;  fishermen are required to report any fish that are recaptured.  (Photo courtesy of Western Fishboat Owners’ Association)

Tuna with Tag Locations

Tuna with Tag Locations

Another method is quadrat sampling.  The organisms in a subset area (quadrat) are counted and then the overall population in the entire area is calculated.  For example, in the picture below, one quadrat would be randomly selected and the organisms counted.  From this count the overall population would be extrapolated.  (Photo courtesy of BBC Bitesize Biology)

Quadrat Sampling

Quadrat Sampling

The sampling method used on the Oscar Dyson employs the use of a transect line.  The picture below illustrates the use of a transect line.  On various increments along the transect line, samples of populations are taken.  Imagine the Oscar Dyson’s path  on the sea as the measuring tape and the trawl net is the sampling square.  (Photo courtesy of Census of Marine Life Organization)

Transect Line Sampling

Transect Line Sampling

The overall survey area of the pollock study this summer is the northern Gulf of Alaska between the shore and the continental break.  Within this area transect lines were established.  These are pathways that the Oscar Dyson will travel along and periodically take samples of the fish.

The current set of transects are 25 nautical miles apart and are parallel, but transects in other areas may be 2 or 5 nautical miles apart.  One nautical mile is equal to 1/60 of a degree (or 1 minute ) of latitude. Transects that we are following now are located on the shelf and are perpendicular to the coastline.  Transects in inlets and bays may run differently, perhaps even zigzag.

Screen Shot of Oscar Dyson Transect Line Travel

Screen Shot of Oscar Dyson Transect Line Travel

If fish are located through acoustics monitoring off the transect line,  the ship might break transect (a mark is made on the map), circle around to the desirable position, and collect a sample by trawling.  The population of pollock can then be mathematically calculated from counting the sample.  After trawling, the ship will return to the break and continue along the transect line.

Most days, scientists hope that the Oscar Dyson will finish a transect line by nightfall and then the ship can be at the next transect by sunrise.  This maximizes the time for detecting fish acoustically and trawling to collect samples.

Personal Log: 

In his 1943 paper “A Theory of Human Motivation,” Abraham Maslow, a developmental psychologist, proposed a hierarchy of needs which focus on describing the stages of growth in humans.  The largest, most fundamental needs are at the bottom, and as those are satisfied, individuals are able to progress up the pyramid.  So, I am going to use this diagram (somewhat tongue-in-cheek) to discuss how  basic needs are met on the ship.  In today’s blog, I will begin the discussion at the bottom level (where else?).
A Version of Maslow's Hierarchy of Needs

A Version of Maslow’s Hierarchy of Needs

The bottom layer includes the most basic physiological needs one requires for survival:  food, water, warmth, and rest.  (We might also include exercise in this level).   So, let us begin at the beginning.
Food

Food is available in the galley.  It is planned for and shopped for before the mission.  Chief Steward, Ava, and Second Cook, Adam, do an excellent job preparing and executing delicious, healthy meals at set times during the day (Breakfast: 7 to 8 am, Lunch 11 am to noon, Dinner 5 to 6 pm). Since the staff on the ship are working around the clock, there is always food available (salad bar, cereal, yogurt, peanut butter and jelly sandwiches) if meal time is missed for sleeping.  Below is a photo of the galley.  (What are those neon yellow things on the bottom of the chair legs for, do you think?)

Oscar Dyson Galley

Oscar Dyson Galley

Water

Water is needed for in several capacities on the ship.  The staff on the ship needs potable water to drink and to cook with.  Additionally,  water is needed for washing dishes, bathing, flushing toilets and doing laundry.

To get clean drinking water, we pump the salt water from the ocean into a desalination unit (a distiller). The distilled water is then sent to a 10,000 gallon holding tank. When water is needed, it is pressurized so that it will move to the faucets, drinking fountains, showers, and so on.

Water is also needed on the ship in the lab and on the deck to clean up after the catch is hauled in and processed.   The water used here is salt water and is pumped onto the boat directly from the ocean.

Rest

Half of the staff on the ship is working around the clock; the other half is resting.   For the science staff, there are two shifts, a morning shift (4 am to 4 pm) and an evening shift (4 pm to 4 am).  The shifts are staggered at these hours so that the evening shift will be able to share two meals with the rest of the staff (usually lunch and dinner).  In most cases, two people share a stateroom:  one works days and the other works nights.  Because the quarters are close on a ship, this gives each person some time alone in the room to sleep, bathe, and take care of other personal needs.  A stateroom consists of a bunk bed, a desk, two lockers, and a bathroom/shower.  Below are some photos of the stateroom that I share with my roommate, Abby.  (Note:  Because rooms are small and space is shared, it is not advisable to bring a large purple suitcase that won’t fit inside one’s locker.)

Oscar Dyson Stateroom

Oscar Dyson Stateroom

Oscar Dyson Stateroom Bath

Oscar Dyson Stateroom Bath

Exercise

There are two workout areas on the ship.  One workout area has a treadmill, an elliptical machine, a bike, and a yoga mat; the other has a treadmill, a rowing machine, and some free weights.  There are limited walking spaces on the ship, so these machines provide a way to stretch one’s legs, so to speak.

Oscar Dyson's Exercise Room

Oscar Dyson’s Exercise Room

 
Did you Know?
With a bachelor’s degree in science, math, or engineering and a 6 month training program at the US Coast Guard Academy in New London, CT, one can serve the United States as a member of the National Oceanic and Atmospheric Administration’s Commissioned Officer Corps (NOAA Corps).  Members of the NOAA Corps serve as operational experts, taking researchers to sea and helping to generate environmental intelligence.  My roommate, Abby, serves as a member of the NOAA Corps.
Abby Controlling the Oscar Dyson

Abby Controlling the Oscar Dyson

This is Abby’s second cruise with the NOAA Corps.  She has a bachelor’s degree in chemistry and just completed her NOAA officer basic training.  One of her tasks is to be ready to deploy specific measures in case of a fire on board.  Below, she is reviewing all of the locations on the Oscar Dyson with fire response equipment.  For more information on NOAA Corps, click on the link.
Abby Locating Fire Response Equipment

Abby Locating Fire Response Equipment

Something to Think About
Knowing geography is essential to various positions on the ships such as scientific exploration and navigation.  Many types of maps are seen on board, for example, computer generated bathymetric maps show the contour and depth of the ocean.  Equally valuable are the “old school” tools (paper maps, compasses, straight edges, and pencils) used to plot the ship’s course.
Navigation Tools

Navigation Tools

Plotting Transects

Plotting Transects

Fun Fact

Etymology is the study of the origin of words.  Many of the words in science originate from ancient languages such as Greek or Latin.   For example, the word etymology comes to us from two Greek words: etymon meaning “the true sense of a word combined with  logia meaning “doctrine, study.” Combining these two roots gives us “the study of the true sense of words,” which can be said to be the meaning of the word etymology.

Here are some root words I came across today all originating from Greek words:

zoo-from zoion meaning “animal”

phyto-from phyto meaning “plant”

plankton-from planktos meaning “drifting” or “wandering”

vorous-from vorous meaning “eating”

In the blogs thus far, I have discussed two species:  walleye pollock and one of their prey, krill.  Krill are classified as zooplankton, literally “animals that drift. ” Krill eat phytoplankton, or “animals that drift.”  Pollock are considered to be zooplanktivorous, or “drifting animal eaters.”  An award winning short video explaining The Secret Life of Plankton can be viewed by clicking on the link.

Melissa George: Yakutat or Bust, July 24, 2013

NOAA Teacher at Sea
Melissa George
Aboard NOAA Ship Oscar Dyson
July 22, – August 9, 2013

Mission:  Pollock Survey
Geographical Area of Cruise:  Gulf of Alaska
Date:  Wednesday, July 24, 2013

Current Data From Today’s Cruise

Weather Data from the Bridge (6:00 am Alaska Daylight Time)
Sky Condition: Scattered Clouds
Temperature: 12º C
Wind Speed: 12 knots
Barometric Pressure:  1017.2 mb
Humidity: 93%

Sun and Moon Data
Sunrise:  5:40 am
Sunset: 10:38 pm

Moonrise:  10:36 pm (July 23, 2013)
Moonset:  9:11 am

Sunrise on July 24, 2013

Sunrise on July 24, 2013

Geographic Coordinates  (6:00 am Alaska Daylight Time)
Latitude: 58º 30.5’ N   Longitude:  150º 53.9’ W

The ship’s position now can be found by clicking:

Oscar Dyson’s Geographical Position

Science and Technology Log

This blog is titled Yakutat or Bust because there is a great deal of hope to complete the survey around Yakutat, Alaska in the southeast.  On the map below, the green mark is our position in the water near Kodiak Island (the survey actually began a bit west near the islands of Four Mountains) and the red is our final destination of Yakutat Bay.  (Photo courtesy of GoogleEarth)

Gulf of Alaska Map

Gulf of Alaska Map

http://www.msc.org/track-a-fishery/fisheries-in-the-program/certified/pacific/gulf-of-alaska-pollock

The purpose of this cruise is to survey the walleye pollock (Theragra chalcogramma) in the Gulf of Alaska. Pollock is a significant fishery in the United States as well as the world.  Pollock, a certified sustainable fishery, is processed into fish sticks, fish patties and imitation crab.  Last year, about 3 million tons of pollock were caught in the North Pacific.  The scientists on board will collect data to determine the pollock biomass and age structure.  These data are used with results from other independent surveys to establish the total allowable pollock catch.

Our First Pollock Catch

Our First Pollock Catch

According to the Alaska Fisheries Science Center, typically pollock grow to about 50 cm and weigh about .75 kg.  They live in the water column and feed on small krill, zooplankton, and small fish as they grow.  As they age they will eat other pollocks.  Sexual maturity is reached around age 4.  Spawning and fertilization occurs in the water column in early spring.  The eggs stay in the water column and once hatched are part of the zooplankton until they are free swimming.

The general process used to catch the pollock involves multiple parts.  I will break down those steps in a series of blogs.  But basically, acoustics are used to locate fish in the water column.  Once the scientists have located the fish along the transect (transects are the paths that the ship will travel on so the scientists can collect data), the Oscar Dyson sets out a trawl equipped with a camera.  The trawl is brought in and data from the catch is documented.  And then the ship continues on.

Bringing in the Aleutian Wing Trawling (AWT) Net

Bringing in the Aleutian Wing Trawling (AWT) Net

Trawling is usually completed only during daylight hours.  Fortunately the sun does not set here in Alaska right now until after 10 pm.  When it is dark, work aboard the Oscar Dyson continues.  For example, one of the scientists is documenting the sea floor with a drop camera.  She is looking at life that is there as well as potential threats to the trawl nets for the bottom trawl surveys.

Preparing the Drop Camera

Preparing the Drop Camera

Questions to Think About:

  • How do scientists use acoustics to locate pollock?
  • How are the transects locations determined?
  • How are pollock and the rest of the catch processed?
  • What information is retrieved from the trawl camera and other types of sensors?
  • What is a bottom trawl and how is it different from a mid-water trawl?
  • What types of careers are available on the Oscar Dyson?

Personal Log: 

Before we left Kodiak Island on July 22, I was able to spend a day exploring alone and with some of the members of the science team while the crew prepared the ship.  The town of Kodiak is one of seven communities on the island and the central location for all commercial transportation on and off the island either by airplane or ferry boat.  

Flying into the Kodiak Airport

Flying into the Kodiak Airport

Kodiak is the ancestral land of the Sugpiaq, native Alaskans of the Alutiq Nation, who subsisted by hunting, fishing, farming, and gathering.  Russian explorers were the first outsiders to visit the island, and under Grigory Shelikof, established a settlement in 1792 that became the center of Russian fur trading.  Following the 1867 Alaska Purchase from Russia, the island and the rest of Alaska became the 49th of the United States in 1959.  Russian influence is still apparent on Kodiak:  the Shelikof Strait separates Kodiak Island from mainland Alaska and the Holy Resurrection Russian Orthodox Cathedral holds a full house on Sunday mornings.

Holy Resurrection Russian Orthodox Church

Holy Resurrection Russian Orthodox Church

Flora and fauna are abundant in this beautiful location.  On a short hike, I was able to sample the delicate salmonberries; fear the beautiful, yet invasive and poisonous hogweed; and watch a gorgeous sunset.

Delicate Salmonberries

Delicate Salmonberries

Invasive Hogweed

Invasive Hogweed

Sunset on Kodiak Island

Sunset on Kodiak Island

Did You Know?

The background of scientists on the Oscar Dyson varies; however, most have a strong affinity for the ocean and spent a lot of time outdoors exploring nature and playing with various critters as children. Kirsten, for example, is a post-doctoral researcher funded by the National Research Council.  She has a BS degree in Marine Biology from Roger Williams University in Rhode Island as well as MS and PhD degrees in Oceanography and Coastal Sciences with a concentration in Fishery Science from Louisiana State University in Baton Rouge.  She came aboard the ship to develop a time series of krill distribution in the Gulf of Alaska and to relate that to other species of importance such as pollock.

Kirsten's Krill Collection

Kirsten’s Krill Collection

Something to Think About: 

STEM (Science, Technology, Engineering, and Math) are not the only important subjects to know to work on the Oscar Dyson.  All three crews on the ship (NOAA Corp, Deck/Fishery Crew, and Scientists) use writing every day. Below are pictures of two log books: one records Weather Data by the NOAA Corp and the other Scientists’ notes.

NOAA Corp Weather Log

NOAA Corp Weather Log

Scientists' Trawling Log

Scientists’ Trawling Log

Fun Fact:

Alaska’s official flag is based on a design by Benny Benson, a thirteen year old boy.  It was submitted in a territory-wide contest for schoolchildren sponsored by the American Legion in 1926.  Benny Benson chose the background color of the flag to represent both the blue sky and the forget-me-not. The Alaska legislature later named the forget-me-not as Alaska’s official state flower.  The flag inspired the state song, the lyrics of which are seen in the picture below.  Marie Drake wrote the lyrics, and Elinor Dusenbury composed the song.

A Popular Hang Out on Board

A Popular Hang Out on Board

Paul Ritter: Lock and Load the XBT – The Joke is on Me, July 22, 2013

NOAA Teacher at Sea
Paul Ritter
Aboard the NOAA Ship Pisces
July 16– August 1, 2013 

Mission: Southeast Fishery-Independent Survey (SEFIS)
Geographical area of cruise: southeastern US Atlantic Ocean waters (continental shelf and shelf-break waters ranging from Cape Hatteras, NC to Port St. Lucie, FL)
Date: July 22, 2013

Weather Data from the Bridge

7-22-13 ship data

Science and Technology Log

Yesterday was a very exciting day.  After we dropped off our first traps, the ship’s officers brought the ship to a full stop and it was time to release the CTD.  What is a CTD?  CTD stands for Conductivity, Temperature, and Depth.  The CTD unit  is an array of sensors that is lowered to just above the bottom of the ocean to take a continuous profile of the water column.  Moments after the CTD reaches the bottom it is brought back to the surface and the deck hands bring it back on board the ship.  From here, the scientific crew can analyze the data from the CTD to determine the water conditions for the drop area.  On some expeditions, the CTD is fitted with a device that actually takes water samples at the different depths for chemical and biological analysis.   This information allows the scientists to get a complete picture of the water column where the traps are set and where the fish live.

What is a CTD? CTD stands for Conductivity, Temperature, and Depth.

Another instrument that is used by the ship is the Expendable Bathythermograph or XBT.  This device was used by the military for many years to measure the temperature of the water at various depths.  The most interesting thing about this probe is how it is deployed.

Warren Mitchell, a fisheries biologist for NOAA’s Beaufort Laboratory, decided it would be a good idea for me to be trained firsthand to deploy this vital instrument.  The first thing I had to do was put on my hardhat and safety vest and step on to the recovery deck.  At that point Warren called up to the bridge to ask for permission to drop the XBT.  The officers on the bridge gladly gave us permission and Warren then got me into a launching position with my feet spread apart and my elbow braced on hip.  The CO then happened to walk by and asked me if I had my safety glasses on, to which I immediately said yes.

It was at this point that Warren gave me permission to launch the XBT.  I was excited.  I was ready.  I could not wait for Warren to give me the signal.  The only problem was I did not know the signal and I could not find the trigger.  I did not know what to do.  I was getting worried.  Warren then repeated the orders “launch”.  “How?” I replied.  Tip the barrel forward, lean forward, he replied, and the XBT slid out of the tube into the water.

The joke was on me.  Here I had been led to believe that this was going to be some grand launch something just shy of the space shuttle taking off into space.  The reality was that the XBT just falls into the water.  Very non-exciting for me but everyone on the boat laughed for hours.  So did I.  It is good to be treated like one of the family.  After our final set of traps for the day, I ventured out to see what it is like to work in the acoustics lab.

Warren Mitchell NOAA Scientist instructs Paul Ritter on the proper use of the XBT.

Warren Mitchell NOAA Scientist gives instruction to Paul Ritter on the proper deployment of the XBT.

Personal Log

Monday 7-22-13

Nurse shark outside chevron trap.

Nurse shark outside our chevron trap.

To this point this expedition has been so amazing.  Would you believe there are 3 people aboard the NOAA Ship Pisces that live or once lived within 60 miles from my home town? Crazy I know.  We have had only one medium sized squall to this point with 3 to 5 foot seas.  We have brought up traps with tons of jellyfish, in which I got a nematocyst (jellyfish stinging cell) to the hand.  It was not too bad but I did feel a slight burning sensation.

We have had a number of different types of starfish, all of which I have never seen.  One particular trap that we sent to the ocean floor, while upon retrieval did not have any fish, but did have a secret to share.  After Julie Vecchio, one of our volunteer scientists replayed the video cameras that are on the top of the trap, we discovered that a nurse shark had been trolling the area around our trap. I have seen so many amazing things.  Several days ago we were hauling traps and just as we brought our trap up there was a sea turtle that came up to the boat.  I snapped a couple of photos, as quick as I could and then went right back to work.  It was not two minutes later and I saw a baby sea turtle the size of a fifty cent piece.  Immediately, the first thing that came to my mind was thought of Crush and Squirt from Disney’s Finding Nemo talking to me.

Crush: Okay. Squirt here will now give you a rundown of proper exiting technique.

Squirt: Good afternoon “Paul”. We’re gonna have a great jump today. Okay, first crank a hard cutback as you hit the wall. There’s a screaming bottom curve, so watch out. Remember: rip it, roll it, and punch it.

 Paul: Whoa! Dude! That was totally cool!

Turtle off the port bow.

Turtle off the port bow.

Tuesday July 23, 2013

Somewhere in the middle of the night the wind picked up and so did the waves.  I share a stateroom with Zach Gillum a graduate student from East Carolina University.  This kid is amazing.  We really have become great friends.

One of the great things about this trip is to be totally immersed in an expedition with like-minded people. We will all hang around waiting for traps, or eating dinner and start conversations about some environmental issue or ecological principle.  I sure wished I lived closer to my new friends.  Anyway, our stateroom window is about 4 foot above the waterline.  Many times during the night, our window was under the water as a wave passed by.  When we woke up, the wind and waves increased.  A four to seven foot wave is enough to make many run for the toilet.  So far so good for me when it comes to sea sickness.

I just hope we don’t find any bigger waves.  We gathered on the aft deck as we usually do but we delayed deployment, waiting for improvement in weather conditions.  The major problem we had was with larger waves comes the possibility of the traps bobbing up and down on the ocean floor.  With adverse conditions on pick-up, we are also more likely to drag traps across the bottom.  We set the first six traps, pulled them up and just as we had suspected not many fish.  Around 1:00 P.M. Zeb Schobernd, our Lead Scientist, made the decision to head to another location.   It just goes to show you that when you are at sea, you need to follow the 3 F’s.  Flexibility, fortitude, and following orders.

Waiting to work.

Waiting to work.

Did You Know?

Did you know that a jelly fish’s nematocyst are like mini speargun?

These little stinging cells fire when they come in contact with the surface of and organism.  Some jellyfish tentacles can contain up to 5000 or more nematocyst.

Susy Ellison: Dreaming of the Cool North, July 22, 2013

NOAA Teacher at Sea
Susy Ellison
Aboard NOAA Ship Rainier
September 9-26, 2013

Mission:  Hydrographic Survey
Geographic Area: South Alaska Peninsula and Shumagin Islands
Date:  July 22, 2013

In September I will be heading north for 3 weeks as a NOAA Teacher at Sea (TAS).  Right now it’s over 90F outside and I am happily visualizing wearing layers of fleece and waterproof raingear on the deck of the NOAA Ship Rainier assisting with hydrographic survey work along the South Alaska Peninsula and Shumagin Islands.

How am I preparing for my experience?  First and foremost, it’s important to actually practice blogging and communicating using the TAS website.  Since this is the platform that will enable me to communicate with my coworkers, students, and all of you out there in the blogosphere, it’s important to learn how to manipulate all the nuances of electronic communication.  Second, I need to learn about the work I will be involved in during my TAS cruise.  Third, since I will be gone during the school year, I need to design lessons and unit plans that will enable students and staff at school to follow along during my experience.  Finally, since it’s still summer vacation, I need to make sure that I get out there!!

A visit to Niagara Falls

I am Susy Ellison, a teacher at Yampah Mountain High School in Glenwood Springs, CO.  Yampah is a public, alternative high school serving students from 4 school districts.  Our students come to us for a variety of reasons, although most are united in their search for a high school experience that helps them identify and pursue their passions while providing information in a relevant, hands-on manner.  I am the sole science teacher for our school, responsible for teaching earth, life, and physical science classes, as well as taking students outdoors for weeklong trips in the nearby mountains and deserts. My passion is environmental literacy, creating connections between people and their planet.  My students will tell you that, no matter what class they are taking, they learn about the planet and how their actions matter.

If you’ve been a good follower of the TAS blogs, you will already know that there have been 4 teachers cruising along on the Rainier (2 of them are on the ship right now).  I have been following their blogs to learn about the science and daily life aboard the ship.  It is exciting to know that there are still places that need to be mapped. I am looking forward to gaining firsthand knowledge of the mapping technology that is used. The one thing that I have noticed is always mentioned in their blogs, besides the science, is the fact that no one is malnourished onboard the ship!

In the coming weeks I will be designing lesson and unit plans for my science classes so that they will be able to follow along while I am at sea. Since Yampah takes an integrated approach to education, I am also creating lessons that our math, language arts, and social studies teachers will be using to add a little hydrographic science to their classes.  The lessons will revolve around the theme of ‘Mapping Our World’, which just happens to be this year’s theme for Earth Science Week.

Finally, my preparations include having an action-packed summer vacation.  I am lucky enough to live in western Colorado, close to mountains, rivers, and deserts.  I have spent part of the summer floating rivers in Utah and Idaho with my husband and friends.  Now, as the waters ebb, I am heading to the mountains for some altitude-adjustment and hiking.  The wildflowers are lovely, and the high-elevation hiking helps me beat the heat (and stay in shape!).

My husband in the dory he built.

My husband in the dory he built.

Floating in my kayak on the Green River

Floating in my kayak on the Green River

I have a wonderful 'backyard'!

I have a wonderful ‘backyard’!

Stay tuned as my cruise approaches for more of my preparations and, perhaps, some glimpses of the lessons I will be preparing for my students.

Rosalind Echols: Sound Off! From Noise to Nautical Charts, July 22, 2013

NOAA Teacher at Sea
Rosalind Echols
Aboard NOAA Ship Rainier (NOAA Ship Tracker)
July 8 — 25, 2013 

Mission: Hydrographic Survey
Geographical Area of Cruise: Shumagin Islands, Alaska
Date: July 22, 2013

Current Location: 54° 55.6’ N, 160° 10.2’ W

Weather on board: Broken skies with a visibility of 14 nautical miles, variable wind at 22 knots, Air temperature: 14.65°C, Sea temperature: 6.7°C, 2 foot swell, sea level pressure: 1022.72 mb

Science and Technology log:

Teamwork, safety first

Rainier motto, painted in the stern of the ship above the fantail, the rear lower outside deck where we have our safety meetings.

“Teamwork, Safety First”, is inscribed boldly on the Rainier stern rafter and after being aboard for more than 2 weeks, it is evident this motto is the first priority of the crew and the complex survey operation at hand.

Rainier launch

This is one of the survey launches that we use to gather our survey data. In this case, the launch is shown approaching the Rainier, getting ready to tie up.

It’s a rainy overcast morning here in SW Alaska and we are circled around the officers on the fantail for the daily safety meeting. Weather conditions, possible hazards, and the daily assignment for each launch are discussed. Per the instructions on the POD (Plan of the Day), handed out the previous evening, the crew then disperse to their assigned launches. The launches are then one-at-a-time lowered into the water by the fancy davit machinery and driven away by the coxswain to their specific “polygon” or survey area for the day. A polygon surveyed by a launch on average takes 2-3 hours at 6-8 knots to survey and usually is an area that is inaccessible by the ship. Many polygons make up one large area called a “sheet” which is under the direction of the “sheet manager”. Several sheets make up an entire survey project. Our hydrographic project in the Shumagins has 8 sheets and makes up a total of 314 square nautical miles.

Safety meeting

The CO, XO, and FOO lead the safety meeting for the day, discussing weather conditions, water conditions, and the assignments for each launch.

Shumagin Islands

This is a chart of the Shumagin Islands showing the 8 sheets (highlighted in green) that we are surveying.

Polygons

East side of Chernabura Island divided into survey “polygons”, each labeled with a letter or word. Notice how each polygon is a small subset of the larger sheet.

On board each launch we have a complex suite of computer systems: one manages the sonar, another manages the acquisition software, and the third records the inertial motion of the launch as it rocks around on the water (pitch, heave, roll). The acquisition system superimposes an image of the path of the launch and the swath of the sonar beam on top of a navigational chart within the polygon. Starting at one edge of the polygon, the coxswain drives in a straight a line (in a direction determined by the sheet manager), to the other end of the polygon, making sure there is some overlap at the boundaries of the swaths. He/she then works back in the other direction, once again making sure there is some overlap with the adjacent swath. We call this “mowing the lawn,” or “painting the floor” as these are visually analogous activities. Throughout the day, we pause to take CTD casts so that we have a sound velocity profile in each area that we are working.

Launches

Typical launch dispersal for a survey day. Launches are signified by “RA-number”. You can also see the location of our tide measurement station and GPS control station, both of which we use to correct our data for errors.

Mowing the lawn

This image shows the software tracking the path and swath of the launch (red boat shape) as it gathers data, driving back and forth in the polygon, or “mowing the lawn.” The darker blue shaded area shows overlap between the two swaths. The launch is approaching a “holiday”, or gap in the data, in an effort to fill it in.

You might be wondering, why the swath overlap? This is to correct for the outer sonar beams of the swath, which can scatter because of the increased distance between the sea floor and the sonar receiver below the hull of the boat. The swath overlap is just one of the many quality control checks built into the launch surveying process. Depending on the “ping rate”, or the number of signals we are able to send to the bottom each second, the speed of the boat can be adjusted.  The frequency of the sound wave can also be changed in accordance with the depth. Lower frequencies (200 khz) are used for deeper areas and higher frequencies (400 khz) are used for shallower areas.

Rosalind in launch

Rosalind in front of the computers on the launch, checking for sonar quality (right screen) and observing the path of the ship, to make sure there are no gaps in the data, or “holidays”.

Despite what might seem like mundane tasks, a day on board the launch is exhausting, given the extreme attention to detail by all crew members, troubleshooting various equipment malfunctions, and the often harsh weather conditions (i.e. fog, swells, cool temperatures) that are typical of southwest Alaska. The success of the ship’s mission depends on excellent communication and teamwork between the surveyors and the coxswain, who work closely together to maximize quality and efficiency of data collection. Rain or shine, work must get done.  But it doesn’t end there. When the launches arrive back at the ship, (usually around 4:30 pm), the crew will have a debrief of the day’s work with the FOO (field operations officer) and XO (executive officer). After dinner, the survey techs plunge head first (with a safety helmet of course) into the biggest mountain of data I have EVER witnessed in my life, otherwise known as “night processing”. We are talking gigabytes of data from each launch just for a days work.  It begins with the transferring of launch data from a portable hard drive to the computers in the plot room. This data is meticulously organized into various folders and files, all which adhere to a specific naming format. Once the transferring of data has finished, the “correction” process begins. That’s right, the data is not yet perfect and that’s because like any good science experiment, we must control for extraneous factors that could skew the depth data. These factors include tides, GPS location error, motion of the launch itself, and the sound velocity in the water column.

Plot room

Our chief surveyor works in the plot room cleaning and correcting data.

Data cleaning.

Data showing the consequences of the tide changing. The orange disjointed surface shows the data before it was adjusted for the tide changing. You can see how the edges between swaths (i.e. red and olive green) do not match up, even though they should be the same depth.

Sound speed artifact

This image shows the edge effects of changing sound speed in the water column. The edges of each swath “frown” because of refraction owing to changing density in the water column. This effect goes away once we factor in our CTD data and the sound speed profile.

In previous posts, I discussed how we correct for tides and the sound velocity. We also correct for the GPS location of the launch during a survey day, so that any specific data point is as precisely located as possible. Although GPS is fairly accurate, usually to within a few meters, we can get even more precise by accounting for small satellite errors throughout the day. The Coast Guard provided Differential GPS allows us to position ourselves to within a meter. To get even more precise, within a few centimeters, we determination location of a nearby object (our Horizontal Control, HorCon, Station) very precisely, and then track the reported position of this object throughout the day. Any error that is recorded for this station is likely also relevant for our launch locations, so we use this as the corrector. For example, if on July 21, 2013, at 3pm, the GPS location of our Bird Island HorCon station was reported 3cm north of its actual location, then our launches are also probably getting GPS locations 3cm too far north, so we will adjust all of our data accordingly. This is one of the many times we are thankful for our software. We also account for pitch, heave, and roll of the launch using the data from the inertial motion unit. That way, if the launch rolled sideways, and the center beam records a depth of 30 meters, we know to adjust this for the sideways tilt of the launch.

HorCon station

This shows the set up of our Horizontal Control and tide gauge station. The elevated rock position was chosen to maximize satellite visibility.

After all correctors have been applied (and a few software crashes weathered), the survey technicians then sort through all the data and clean out any “noise.” This noise represents sound reflections on sea life, air bubbles, or other items that are not part of the seafloor. Refraction of sound waves, as mentioned in the last post, is caused by density changes in the water due to changes in the temperature, pressure, or salinity.

Dirty data

This shows sonar data with “noise”. The noise is the seemingly random dots above and below the primary surface. On the surface itself, you can see data from four different swaths, each in a different color. Notice the overlap between swaths and how well it appears to be matching up.

Cleaned surface

This shows sonar data after the “noise” has been cleaned out. Notice how all data now appears to match a sea floor contour.

Many of the above correctors are applied the same day the data is collected, so the sheet manager can have an up-to-date record of the project’s progress before doing final planning for data collection the next day. After a sheet has been fully surveyed and ALL correctors applied, the sheet manager will complete a “descriptive report”, which accompanies the data and explains any gaps in the sonar data (“holidays”) and/or other errors present. This report, along with the data, is sent to the Pacific Hydrographic Branch for post-processing and Quality Control. After that the data is forwarded to the Marine Charting Division where the data undergoes a final set of Quality Assurance checks and is put in a format that can be printed on a paper nautical chart. From acquisition on the launches to publication on a chart, the process can take up to two years! The length of the process is designed to ensure maximum accuracy as many mariners rely on accurate charts for safe navigation.

Personal Log

As the saying goes, “When in Rome, do as the Romans.” One of the attractions of life in Alaska is access to excellent fishing, and a wide variety of tasty fish species. Although I normally consider myself to be a fairly outdoorsy person, thus far in my life this had not extended to the activity of fishing. However, inspired by Avery’s enthusiasm, and her first successful halibut catch, I decided at least give it a try, obtaining an Alaska fishing license and preparing myself for yet another adventure. I am, after all, always encouraging other people to try new things, especially things that make them a bit nervous, so it only felt right to follow some of my own advice. Honestly speaking, though, the thought of catching the fish and then having to deal with the consequences made me a little anxious.

Rosalind with fish

Rosalind with her first ever fish catch, trying very hard to keep her fingers away from the tip of the hook and the very spiny and painful back fin of the fish. Black rock fish have venomous points on their fins.

Fortunately, I had excellent guidance in this activity, setting out with Avery and two very patient crew members, who put up with my initial lack of skill and muscle, and intense enthusiasm about even the smallest jellyfish in the water. I had realized after my shoreline rock verification expedition that pointing at everything in the water and shouting “Look!” was probably not that helpful if we were trying to identify rocks, but here it seemed more appropriate. At least if you think jellyfish are cool. After several lackluster hours, we finally found a spot where a group of Black Rock Fish were schooling, and caught quite a few very quickly. Not surprisingly, the fish aren’t that happy about being caught and flail around a fair amount. Considering that they have pointy, venomous spines in their dorsal fin, it takes great care to get the fish in the bucket without injury, but we successfully managed it.

Rosalind cleaning

Rosalind learning how to fillet a black rock fish. Notice the safe distance between knife and fingers!

Somehow, in all my years of school, I never actually dissected anything, and have always felt a little squeamish around dead animals. However, after helping catch the fish, I couldn’t very well leave my colleagues alone to deal with the arduous task of filleting and cleaning the fish, so I decided to do my best to participate. It actually went much better than I expected, and I learned quite a bit about fish anatomy along the way. For example, fish have an air bladder that allows them to float. They look much less impressively large when this is deflated.

Fish fillets

A sampling of our collection of black rock fish fillets, mid-way through cleaning. I am proud to have contributed to this!

All in all, it was a very satisfying experience. It is nice to be able to say that I have developed a somewhat useful life skill (fishing as well as avoiding my fingers with large knives). Our wonderful cook, Kathy, even used some of the fish for a delicious lunch of fish tacos, which I hope to try to replicate myself some time in the near future.

FIsh tacos

Delicious fish tacos made from Black Rock Fish caught by Rainier crew and Teachers at Sea Rosalind and Avery!

Fun Fact: a fathom, a maritime measurement for depth equal to six feet, was originally based on the distance between a man’s outstretched finger tips. The word itself derives from an Old English word meaning outstretched or embracing arms. Given that we use it to measure depth, it is also interesting to note that it is related to the word to fathom something, or the adjective unfathomable, meaning immeasurable. The word is also related to the phrases “six feet under” and to “deep six” something.

Avery Marvin: Sound Off! From Noise to Nautical Charts, July 22, 2013

NOAA Teacher at Sea
Avery Marvin
Aboard NOAA Ship Rainier (NOAA Ship Tracker)
July 8 — 25, 2013 

Mission: Hydrographic Survey
Geographical Area of Cruise: Shumagin Islands, Alaska
Date: July 22, 2013

Current Location: 54° 55.6’ N, 160° 10.2’ W

Weather on board: Broken skies with a visibility of 14 nautical miles, variable wind at 22 knots, Air temperature: 14.65°C, Sea temperature: 6.7°C, 2 foot swell, sea level pressure: 1022.72 mb

Science and Technology log:

Teamwork, safety first

Rainier motto, painted in the stern of the ship above the fantail, the rear lower outside deck where we have our safety meetings.

“Teamwork, Safety First”, is inscribed boldly on the Rainier stern rafter and after being aboard for more than 2 weeks, it is evident this motto is the first priority of the crew and this complex survey operation at hand.

Rainier launch

This is one of the survey launches that we use to gather our survey data. In this case, the launch is shown approaching the Rainier, getting ready to tie up.

It’s a rainy overcast morning here in SW Alaska and we are circled around the officers on the fantail for the daily safety meeting. Weather conditions, possible hazards, and the daily assignment for each launch are discussed. Per the instructions on the POD (Plan of the Day), handed out the previous evening, the crew then disperse to their assigned launches. The launches are then one-at-a-time lowered into the water by the fancy davit machinery and driven away by the coxswain to their specific “polygon” or survey area for the day. A polygon surveyed by a launch on average takes 2-3 hours at 6-8 knots to survey and usually is an area that is inaccessible by the ship. Many polygons make up one large area called a “sheet” which is under the direction of the “sheet manager”. Several sheets make up an entire survey project. Our hydrographic project in the Shumagins has 8 sheets and makes up a total of 314 square nautical miles.

Safety meeting

The CO, XO, and FOO lead the safety meeting for the day, discussing weather conditions, water conditions, and the assignments for each launch.

Shumagin Islands

This is a chart of the Shumagin Islands showing the 8 sheets (highlighted in green) that we are surveying.

Polygons

East side of Chernabura Island divided into survey “polygons”, each labeled with a letter or word. Notice how each polygon is a small subset of the larger sheet.

On board each launch we have a complex suite of computer systems: one manages the sonar, another manages the acquisition software, and the third records the inertial motion of the launch as it rocks around on the water (pitch, heave, roll). The acquisition system superimposes an image of the path of the launch and the swath of the sonar beam on top of a navigational chart within the polygon. Starting at one edge of the polygon, the coxswain drives in a straight a line (in a direction determined by the sheet manager), to the other end of the polygon, making sure there is some overlap at the boundaries of the swaths. He/she then works back in the other direction, once again making sure there is some overlap with the adjacent swath. We call this “mowing the lawn,” or “painting the floor” as these are visually analogous activities. Throughout the day, we pause to take CTD casts so that we have a sound velocity profile in each area that we are working.

Launches

Typical launch dispersal for a survey day. Launches are signified by “RA-number”. You can also see the location of our tide measurement station and GPS control station, both of which we use to correct our data for errors.

Mowing the lawn

This image shows the software tracking the path and swath of the launch (red boat shape) as it gathers data, driving back and forth in the polygon, or “mowing the lawn.” The darker blue shaded area shows overlap between the two swaths. The launch is approaching a “holiday”, or gap in the data, in an effort to fill it in.

You might be wondering, why the swath overlap? This is to correct for the outer sonar beams of the swath, which can scatter because of the increased distance between the sea floor and the sonar receiver below the hull of the boat. The swath overlap is just one of the many quality control checks built into the launch surveying process. Depending on the “ping rate”, or the number of signals we are able to send to the bottom each second, the speed of the boat can be adjusted.  The frequency of the sound wave can also be changed in accordance with the depth. Lower frequencies (200 khz) are used for deeper areas and higher frequencies (400 khz) are used for shallower areas.

Rosalind working the surveying computers in the launch

Rosalind working the surveying computers in the launch

Despite what might seem like mundane tasks, a day on board the launch is exhausting, given the extreme attention to detail by all crew members, troubleshooting various equipment malfunctions, and the often harsh weather conditions (i.e. fog, swells, cool temperatures) that are typical of southwest Alaska. The success of the ship’s mission depends on excellent communication and teamwork between the surveyors and the coxswain, who work closely together to maximize quality and efficiency of data collection. Rain or shine, work must get done.  But it doesn’t end there. When the launches arrive back at the ship, (usually around 4:30 pm), the crew will have a debrief of the day’s work with the FOO (field operations officer) and XO (executive officer). After dinner, the survey techs plunge head first (with a safety helmet of course) into the biggest mountain of data I have EVER witnessed in my life, otherwise known as “night processing”. We are talking gigabytes of data from each launch just for a days work.  It begins with the transferring of launch data from a portable hard drive to the computers in the plot room. This data is meticulously organized into various folders and files, all which adhere to a specific naming format. Once the transferring of data has finished, the “correction” process begins. That’s right, the data is not yet perfect and that’s because like any good science experiment, we must control for extraneous factors that could skew the depth data. These factors include tides, GPS location error, motion of the launch itself, and the sound velocity in the water column.

Plot room

Our chief surveyor works in the plot room cleaning and correcting data.

Data cleaning.

Data showing the consequences of the tide changing. The orange disjointed surface shows the data before it was adjusted for the tide changing. You can see how the edges between swaths (i.e. red and olive green) do not match up, even though they should be the same depth.

Sound speed artifact

This image shows the edge effects of changing sound speed in the water column. The edges of each swath “frown” because of refraction owing to changing density in the water column. This effect goes away once we factor in our CTD data and the sound speed profile.

In previous posts, I discussed how we correct for tides and the sound velocity. We also correct for the GPS location of the launch during a survey day, so that any specific data point is as precisely located as possible. Although GPS is fairly accurate, usually to within a few meters, we can get even more precise (within a few centimeters) by accounting for small satellite errors throughout the day. We do this by determining the location of a nearby object (our Horizontal Control, HorCon, Station) very precisely, and then tracking the reported position of this object throughout the day. Any error that is recorded for this station is likely also relevant for our launch locations, so we use this as the corrector. For example, if on July 21, 2013, at 3pm, the GPS location of our Bird Island HorCon station was reported 3cm north of its actual location, then our launches are also probably getting GPS locations 3cm too far north, so we will adjust all of our data accordingly. This is one of the many times we are thankful for our software. We also account for pitch, heave, and roll of the launch using the data from the inertial motion unit. That way, if the launch rolled sideways, and the center beam records a depth of 30 meters, we know to adjust this for the sideways tilt of the launch.

HorCon station

This shows the set up of our Horizontal Control and tide gauge station. The elevated rock position was chosen to maximize satellite visibility.

After all correctors have been applied (and a few software crashes weathered), the survey technicians then sort through all the data and clean out any “noise.” This noise represents sound reflections on sea life, air bubbles, or other items that are not part of the seafloor.  Refraction of sound waves, as mentioned in the last post, is caused by density changes in the water due to changes in the temperature, pressure, or salinity.

Dirty data

This shows sonar data with “noise”. The noise is the seemingly random dots above and below the primary surface. On the surface itself, you can see data from four different swaths, each in a different color. Notice the overlap between swaths and how well it appears to be matching up.

Cleaned surface

This shows sonar data after the “noise” has been cleaned out. Notice how all data now appears to match a sea floor contour.

Many of the above correctors are applied the same day the data is collected, so the sheet manager can have an up-to-date record of the project’s progress before doing final planning for data collection the next day. After a sheet has been fully surveyed and ALL correctors applied, the sheet manager will complete a “descriptive report”, which accompanies the data and explains any gaps in the sonar data (“holidays”) and/or other errors present. This report, along with the data, is sent to the Pacific Hydrographic Branch for post-processing, and in 1-2 years, we will have a corrected and updated navigational chart. During this time the data is reviewed for quality and adherence to hydrographic specifications and then is distilled into a cartographic product (nautical chart) consisting of points, lines, and areas.

Personal Log:

So I am going to hold off in talking about an animal that has recently fascinated me and instead devote this personal log to some cool things I have been doing on the ship.

Most recently I got to be the helmsman and steer the ship. This involved me following orders from the “conning officer” who told me various steering commands such as: “Left ten degrees rudder”, “steady on course 167°”, “ease 5° right”, “helm in auto” (auto-pilot). To acknowledge the command, I repeated what the conning officer said followed by “aye”. For example: “Left ten degrees rudder, aye” or “course 167°, aye”.  When the boat is actually on the course that was requested by the conning officer, I repeated the command with the word “steady”. For example: “Steady on course 167°”

Avery at the helm

Avery at the helm

You might be wondering why all of the commands involve degrees. Well that is because this ship is steered by the rudder, similar to how you manually steer a small sailboat.  So changing the angle of the rudder will change the direction of the ship.  To change this angle, you turn the steering wheel a desired amount of degrees beyond zero in the direction the conning officer instructed.  So if he said “right 5 degrees rudder”, I would turn the steering wheel right, and stop at the 5 hash mark.

Once the boat actually turns 5°, I will make sure I am at the correct “heading” or degree mark that the conning officer instructed.  A heading can be any number between 000-360 (where 000-deg = North, 045 = Northeast, 090 = East, etc.) as this boat can turn in a complete circle and be navigated in any direction.  (There is 360° in both a compass and a circle.)  Once I am steady at the correct heading, I will put the steering wheel back to 0° which means the rudder is completely straight and parallel with the boat. At this point the boat is going straight. If this were a car, you could just stay straight no problem.

But because this boat moves in water and is affected by ocean conditions such as swells, it is easily knocked off course of the heading. So as helmsman I am constantly making tiny adjustments with the steering wheel by a few degrees in either direction to maintain my heading.   This adjustment is done using the steering wheel if I am driving manual, or using a dial on the gear panel if the boat is in “auto” (auto-pilot). Because the ship rudder must “push water out of the way” in order to steer the boat, there is a delay between when I turn the steering wheel to when the ship actually moves that amount of degrees. This is not a car which turns instantaneously by the movement of axles.  So I need to account for that “lag time” as well as ocean conditions and the speed of the boat when turning the ship.  For example, if the boat is going slow (3 knots) and I need to turn quickly, I will have to use a greater rudder angle.  Throughout this process I have several digital screens that show me my current position and course, current heading and desired heading as well as other navigational aides.  When I was helmsman, I was closely monitored and assisted by Jason, a former Navy Chief Boatswain, who is one of the best helmsman on the ship.  To be a good navigator you need to know the fundamentals but you also need a lot of practice and exposure to various navigational situations.

Helm stand

Helm stand

Yesterday, Rosalind and I got to work on deck and help the Chief Boatswain with various deck tasks such as lowering the anchor and assisting with the davit to hoist the launches from their day of surveying out on the water.  Assisting with the job of lifting a 16,000 lb launch with 3 people aboard using the davit winch was by far the most exhilarating experience thus far on the ship. I handled the task with extreme caution. As with being a helmsman, there are many factors I must consider as a davit operator.  For example, if there is a significant swell, I need to be more aggressive with the davit movements to get the boat lifted fast to avoid any excessive swaying in mid-air. Most importantly, I must attentively follow the gestures of the deck boss below who is able to see the launch very clearly and is directing me on every davit movement.  Even an experienced davit operator like Jason, who probably can predict the next davit movement in his sleep, must never assume and then act. He ALWAYS follows the exact orders of the deck officer below because he never knows what they are seeing that he cannot from the above deck.  Overall, with Jason’s close attention and assistance, I think I did a good job of assisting with the davit. The boat made it safely aboard, and my heart returned to a normal beating pattern. 🙂

Operating the crane to get the davit ready to lift the launch out of the water

Getting the davit positioned and ready to lift the launch out of the water.

On a lighter note I learned how to play the good ole’ mariner pastime favorite, Cribbage. Rosalind (the other Teacher at Sea and my delightful roommate) taught me how to play. We had a cribbage tournament here aboard the ship in which about 12 people competed. I did not advance to the finals but had a lot of fun nonetheless.  I am looking forward to gaining more Cribbage strategies so I can be a more competitive player for future matches.

First round of Cribagge tournament

First round of Cribbage tournament

Just for fun:

An adorable sole I caught on the fantail of the Rainer (I released him/her)

An adorable sole I caught on the fantail of the Rainer (I released him/her). 🙂

Fun factoid: A fathom which is a maritime measurement equal to 6 feet, was originally based on the distance, fingertip to fingertip of a man’s outstretched arms. Fathom that!