Kaitlin Baird: The Importance of Sound, September 16, 2012

NOAA Teacher at Sea
Kaitlin Baird
Aboard NOAA Ship Henry B. Bigelow
September 4 – 20, 2012

Mission: Autumn Bottom Trawl Survey with NOAA’s Northeast Fisheries  Science Center
Geographical Area: Off the Coast of Maryland
Date: September 16th

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Location Data:
Latitude: 37’72.10
Longitude: 75′ 17.02

Weather Data:
Air Temperature: 21.0 (approx.70°F)
Wind Speed: 8.71 kts
Wind Direction:  West
Surface Water Temperature: 22.99 °C (approx. 73°F)
Weather conditions: overcast

Science and Technology Log:

It’s day 13 aboard the Henry B. Bigelow and we have made the turn at our southern stations off the coast of North Carolina and are working our way back to port at some of our inshore stations off the coast of Maryland. You may wonder how each of the stations we sample at sea are chosen? The large area of Cape May to Cape Hatteras are broken into geographic zones that the computer will assign a set amount of stations to, marking them with geographic coordinates. The computer picks a set number of stations within each designated area so all the stations don’t end up all being within a mile of each other. Allowing the computer system to pick the points removes human bias and truly keeps the sampling random. The vessel enters the geographic coordinates of the stations into a chartplotting program in the computer, and uses GPS, the Global Positioning System to navigate to them.  The GPS points are also logged on a nautical chart by the Captain and mate so that they have a paper as well as an electronic copy of everywhere the ship has been.

You may wonder, how does the captain and fishermen know what the bottom looks like when they get to a new point? How do they know its OK to deploy the net? Great question. The Henry B. Bigelow is outfitted with a multibeam sonar system that maps the ocean floor.  Some of you reading this blog might remember talking about bathymetry this summer. This is exactly what the Bigelow is doing, looking at the ocean floor bathymetry. By sending out multiple pings the ship can accurately map an area 2.5-3 times as large as its depth. So if the ship is in 20 meters of water it can make an accurate map of a 60 meter swath beneath the boats track. The sonar works by knowing the speed of sound in water and the angle and time that the beam is received back to the pinger . There are a number of things that have to be corrected for as the boat is always in motion. As the ship moves through the water however, you can see the projection of the bathymetry on their screen below up in the wheelhouse. These images help the captain and the fisherman avoid any hazards that would cause the net or the ship any harm.  A good comparison to the boats multibeam sonar, is a dolphins ability to use echolocation. Dolphins send their own “pings” or in this case “echos” and can tell the location and the size of the prey based on the angle and time delay of receiving them back. One of the main differences in this case is a dolphin has two ears that will receive and the boat just has one “receiver”. Instead of finding prey and sizing them like dolphins, the ship is using a similar strategy to survey what the bottom of the sea floor looks like!

Bathymetric data being collected by multibeam sonar technology on the Bigelow

Bigelow multibeam sonar (NOAA)

Echolocation schematic courtesy of the Smithsonian Institute

Personal Log:

The last few days I have been trying my hand at removing otoliths from different species of fish. The otoliths are the ear bones of the fish. Just like the corals we have been studying in Bermuda, they are made up of calcium carbonate crystals. They are located in the head of the bony fish that we are analyzing on the cruise. A fish uses these otoliths for their balance, detection of sound and their ability to orient in the water column.

If you remember, at BIOS, we talk a lot about the precipitation of calcium carbonate in corals and how this animal deposits bands of skeleton as they grow. This is similar in bony fish ear bones, as they grow, they lay down crystalized layers of calcium carbonate. Fisheries biologist use these patterns on the otolith to tell them about the age of the fish. This is similar to the way coral biologists age corals.

I have been lucky enough to meet and learn from scientists who work specifically with age and growth at the Northeast Fisheries Science Center Fishery Biology Program. They have been teaching about aging fish by their ear bones. These scientist use a microscope with reflected light to determine the age of the fish by looking at the whole bone or making slices of parts of the bone depending on what species it is. This data, along with lengths we have been recording, contribute to an age-length key. The key allows biologists to track year classes of the different species within a specific population of fish. These guys process over 90,000 otoliths a year! whew!

The information collected by this program is an important part of the equation because by knowing the year class biologists can understand the structure of the population for the stock assessment.  The Fishery Biology program is able to send their aging and length data over to the Population Dynamics Branch where the data are used in modeling. The models, fed by the data from the otoliths and length data,  help managers forecast what fisheries stocks will do. It is a manager’s job to the take these predictions and try to balance healthy fish stocks and the demands of both commercial and recreational fishing. These are predictive models, as no model can foresee some of the things that any given fish population might face any given year (ie food scarcity, disease etc.), but they are an effective tool in using the science to help aid managers in making informed decision on the status of different fish stocks. To learn more about aging fish please visit here.

Otoliths (fish ear bones) that I removed from a Butterfish

You can see here an otolith that is 1+ years old. It was caught in September and that big 1st band is its Year 0. You can see that the black dot demarks the fish turning 1. You can then see the Summer growth but not yet the winter growth. This fish has not yet turned 2, but it will be Jan 1st of the next year.

I have to end with a critter photo! This is a Cobia (Rachycentron canadum).

Cobia caught off the coast of Maryland

Thanks for reading!

Amanda Peretich: Awesome Acoustics, July 13, 2012

NOAA Teacher at Sea
Amanda Peretich
Aboard Oscar Dyson
June 30, 2012 – July 18 2012

Mission: Pollock Survey
Geographical area of cruise: Bering Sea
Date: July 13, 2012

Location Data
Latitude: 59ºN
Longitude: 174ºW
Ship speed: 11.7 knots (13.5 mph)

Weather Data from the Bridge
Air temperature: 7.3ºC (45.1ºF)
Surface water temperature: 7.6ºC (45.7ºF)
Wind speed: 4.3 knots (4.9 mph)
Wind direction: 12ºT
Barometric pressure: 1010 millibar (1.0 atm, 757.5 mmHg)

Science and Technology Log

How sonar works: energy (sound) waves are pulsed through the water. When it strikes an object, it bounces back to the receiver. (from http://www.dosits.org/)

Before stepping onto the Oscar Dyson, I wasn’t quite sure about much of the science going on. Did they just put the nets in the water every so often and hope to catch some fish? Carefully lean over the side of the ship saying “here fishy fishy” with the hope that the pollock would find their way into the net? Neither of these scenarios is correct (good thing I’m not actually a fisherman!). So today’s lesson is going to be all about what the chief scientist actually uses to find fish: hydroacoustics (hydro meaning water and acoustics meaning sound). This also involves SONAR, which is short for SOund Navigation And Ranging.

Fishfinding basics.

If you’ve ever been on a smaller boat, yacht, fishing vessel, or the like, you may have seen something called a fishfinder. The basic concepts are the same as what is happening on the Oscar Dyson. An echosounder sends a pulse of energy waves (sound) through the water. When the pulse strikes an object (such as the swim bladder in fish), it is reflected (bounced) back to the transducer. This signal is then processed and sent to some sort of visual display.

Swim bladder in a fish.
(from https://www.meted.ucar.edu/)

The Oscar Dyson uses acoustic quieting technology where the scientists can monitor fish populations without altering their behavior. The Scientific Sonar System and various oceanographic hydrophones (underwater microphones) are raised and lowered through the water column beneath the ship on a retractable centerboard. This is important so that the transducers can be lowered away from the flow noise generated by the hull, which in turn will improve the quality of data collected. In addition, there is a multibeam sonar system located on the forward hull. Ultimately the hydroacoustic data is all used as one piece to the puzzle of measuring the biomass of fish in the survey area.

The different sonar signal transmitter/receivers (transducers) used on this leg of the pollock survey and their location on the ship.

Chief scientist Neal working away in the Acoustics lab. The second screen from the left on the upper row is showing the information from the ME70 multibeam.

So how does this all work when we are looking for fish? The chief scientist (Neal on the 0400-1600 watch) or another scientist (Denise on the 1600-0400 watch) will spend a lot of time analyzing the various computer screens in the acoustics lab, which has been affectionately termed the “cave” (no windows). They are looking at the information being relayed from both the multibeam and the EK60.

What is a multibeam? The Oscar Dyson has the Simrad ME70 scientific multibeam echosounder. It is located on the hull (underside) of the ship on the front half and sends 31 sonar beams per second down to the bottom of the sea floor.

Multibeam echosounder.
(from http://www.simrad.com/)

Aft of the multibeam (on the centerboard) are the five Simrad transducers. It may seem confusing, but hopefully I can walk you through a teensy little bit of how it works when we are looking to trawl for fish.

Information from the EK60 transducer at 18kHz (top) and 38kHz (bottom).

Information from the EK60 echosounder is displayed on the far left screen in the acoustics lab while information for the ME70 multibeam is displayed on the next screen. The darker patches are showing that there are fish in that area. When the scientist first starts to see a good amount of fish, they will “mark” it and keep watching. If the screen fills up with fish (as in the EK60 image), the scientist will call upstairs to the bridge and tell them where to head back to on the transect line to start trawling. Depending on the location of the fish in the water column, it may be a bottom trawl (83-112 net), a midwater trawl (AWT net), or a methot trawl. Side note: the 83-112 midwater comparison trawl that I’ve mentioned before is done almost immediately after an AWT midwater trawl to compare the fish caught in a common area.

Information from the ME70 multibeam. You can determine the sea floor depth and there are five narrow beam slices from the mid-section of the multibeam (of the 31 different beams that span 120 degrees) displayed on screen.

Chief scientist Neal up on the bridge.

Then the scientist will head upstairs as the deck crew is preparing the net. One of the many sensors attached to the net is called the FS70 fishsounder or “the turtle”, and it is only used during trawls (because it is attached to the headrope). The scientist can “watch” the fish swimming under the ship using the EK60 information combined with the information from the fishsounder. The yellow “turtle” on the right in the image shows how the FS70 is flying in the water. You want minimal pitch and roll and for the front of it to be facing the back of the ship. This way, we can “see” the fish as they are going through the net. The officer of the deck and lead fisherman or head boatswain can adjust various things to keep the turtle in the right orientation. The middle image below is constantly changing on the screen in the bridge as the sonar is sweeping back and forth, so you can almost watch the individual fish enter the net. It was interesting to watch the delay between when you would see the fish from the EK60 (on the left) and when you saw them with the FS70 (middle).

Display screens on the bridge used during a trawl.

Once the scientist is satisfied that enough fish have been caught for a sufficient sample size, the net will be hauled back and the acoustics work is done for just a little bit (giving Neal some time to grab some well-deserved coffee and the rest of us time to get our rain gear on to process the fish).

So some of the questions I had asked (that don’t really fit nicely in the information above):

Why do we use different frequencies in the acoustic studies?

Relationship between frequency and wavelength. (from http://emap-int.com)

This ties right back in to chemistry (and other sciences) with an equation and the relationship between frequency and wavelength (yay!). Basically there is an inverse relationship which means that at a high frequency there is a smaller or shorter wavelength (wavelength is the distance for peak to peak of a wave). At a low frequency, there is a higher or longer wavelength.

At a low frequency, you will see only see things that are larger, like pollock, whereas you will see very small things like krill and zooplankton at higher frequencies. Having information from both types of frequencies is necessary to complete the scientific research on the Oscar Dyson.

Traveling at 1 knot, showing single fish from EK60 sonar.

Is it possible to see a single fish?
Yes! From sunset to sunrise, the Oscar Dyson doesn’t actually travel the transect lines. This is because the pollock behave differently during darkness than during the day. So instead of traveling between 11 and 12 knots (which is what happens between trawls), it’s almost like the boat is just sitting around for a couple of hours. But during this time, since the boat isn’t moving along quickly, it’s possibly to see individual fish on the sonar as shown in the image.

Hydroacoustic surveys can involve any number of different types and locations of the transducers. (from http://btechgurus.blogspot.com/2012/06/sonar.html)

Personal Log
Today is Friday the 13^th but it was far from unlucky – I finally saw something out in the water other than fog: a boat! Again, all good sightings seem to come from up on the bridge, so I’m thankful for Lieutenant Matt for allowing me to ask a billion questions while I’m up there and teaching me more than I ever thought my brain could hold. He has all of the qualities of a great teacher, which is nice to see.

The ship we saw up on the bridge this morning from about 5 nautical miles away (left), on the sonar (middle), and through the binoculars (right).

Neal and I dancing while waiting for the fish!

Highlight from the other day? Chief scientist Neal finally dressed out in his Grundens (rain gear) and came to help process a catch in the fish lab! While waiting, he even took a quick second to dance in the doorway (we were “Dougie”-ing) to my music that was playing over the speaker system.

References
NOAA Oscar Dyson flier
NOAA Oscar Dyson Ship Electronics Suite
HTI Sonar
Wikipedia: Sonar
Simrad

Marsha Skoczek: North Florida MPA, July 7, 2012

NOAA Teacher at Sea
Marsha Skoczek
Aboard NOAA Ship Pisces
July 6 – 19, 2012

Mission: Marine Protected Areas Survey
Geographic area of cruise:  Subtropical North Atlantic, off the east coast of Florida
Date:  July 7, 2012

Location:
Latitude:  30.262610N
Longitude:  80.12.403W

Weather Data from the Bridge
Air Temperature:  29.2C (84.5F)
Wind Speed:  6.07 knots
Wind Direction:  from the SSW
Relative Humidity:  76%
Barometric Pressure:  1016.8
Surface Water Temperature:  30.82C (87F)

Science and Technology Log

North Florida MPA

Today we made our way about 50 nautical miles off shore to the North Florida Marine Protected Area (MPA) accompanied by dolphins and flying fish.  The North Florida MPAs were closed by the South Atlantic Fishery Management Council to bottom fishing in order to sustain and repopulate the following species of fish:  snowy grouper, yellowedge grouper, Warsaw grouper, speckled hind grouper, misty grouper as well as golden and blueline tilefish.  A second part of our science team is looking at the benthic invertebrates such as corals and sponges as they provide a habitat for the grouper and tilefish to live in.  The types of corals and sponges we expect to see in this area include: black coral, whip coral, purple gorgonian, Tanacetipathes, and the stink sponge.

Pisces deck hands launch the ROV

We did three Remotely Operated Vehicle  (ROV) dives with the Phantom S II.  Each dive was between one and two hours long depending on the bottom conditions.  The winch from the Pisces would lower the ROV to the bottom of the ocean approximately 50-60 meters deep (164 to 196 feet).  The area in the MPA we were looking at had been mapped the night before using the ship’s Multibeam Sonar to give the scientists a better idea of where to look and what type of bottom features they will see.   The current at the bottom for a couple of the dives was about 1.5 knots.  This made it pretty difficult to spend quality time looking at the species.  The Scientists will take this data back to the lab where they can spend more time with each video to fully catalog each species we saw today.

Stephanie Farrington and myself are logging data.

Once the ROV’s cameras were rolling, the science team was able to begin logging all of the different species that they saw.  Each part of the transect line is carefully documented with a date and time stamp as well as a latitude, longitude and depth.  Also mounted on the ROV is a small CTD to collect the temperature and depth every 15 seconds.  This will help the scientists match up all of the details for each habitat that we saw with the video on the ROV.  While the ROV is at the bottom collecting data, there are several different stations going on in the lab at the time.

John Reed and Stephanie Farrington are looking mostly at the benthic invertebrates, Stacey Harter and Andy David are cataloging all of the fish they are able to see and identify, and Lance Horn and Glenn Taylor are manning the ROV.  There is also a fourth station where one of the scientists uses a microphone to annotate the video as it is being recorded onto a DVD.  Today John, Stacey and Andy all took turns at the video annotation station.  Basically they are verbally describing the bottom features and habitat they see as well as all the different species of fish and corals.  This will make it easier for the scientists when they get back into their home labs as they process their data.  For each one hour of video taken it will take Stacey between four and eight hours to catalog each fish found as the ROV passed by.  This information is compiled into a report that will be shared with the South Atlantic Council to show if the targeted species are actually making a comeback in these MPAs.

The snowy grouper is one of the targeted species. We found this one using the ROV swimming back into his burrow.

Today some of the species we saw include reef butterflyfish, vermillion snapper, filogena coral, blue angelfish, purple gorgonian,yellowtail reef fish, black corals, bigeye fish, squirrelfish, wire corals, scamp grouper, hogfish, ircinia sponges as well as a couple of lobsters and a loggerback sea turtle.

Tomorrow we will make several more dives at another site outside the North Florida MPA so we can compare this data with the data taken today inside the MPA.

Personal Log

As part of the abandon ship drill, we had to be able to don our immersion suit in less than three minutes.

Life on the ship is really different in some ways compared to life on land.  There is the constant rocking of the ship, which my inner ears are not very fond of. The bedrooms are not the biggest and we each share with one other person.  I am rooming with Stephanie Farrington and she is very easy to get along with.  The food has been great — it would be very easy to gain weight while working on the Pisces.  The stewards do a fantastic job preparing meals for everyone on the ship.  Meal times are the same each day, breakfast is from 7-8 am, lunch is from 11am to noon, and dinner is from 5-6pm.  If someone is working the night shift, they can request that a meal be set aside for them so they can eat later.

Ocean Careers Interview

Stacey Harter

In this section, I will be interviewing scientists and crew members to give my students ideas for careers they may find interesting and might want to pursue someday.  Today I interviewed Stacey Harter, the Chief  Scientist for this mission.

What is your job title?  I am a Research Ecologist at NOAA Fisheries Panama City Lab.

What type of responsibilities do you have with this job?  My responsibilities are to acquire funding for my research, as well as plan the trips, go on the cruise to gather the data, and analyze the data when I get back.  I am also collaborating on other projects with NOAA Beaufort in North Carolina and St. Andrew Bay studying the juvenile snapper and grouper populations in the sea grass found at this location.

What type of education did you need to get this job?  I got my Bachelors degree in Biology from Florida State University and my Masters degree in Marine Biology from University of Alabama.

What types of experiences have you had with this job?  My best experience I’ve had was getting to go down in a manned submersible to a depth of 2,500 feet to study deep water corals and the fish that live there.

What is your best advice for a student wanting to become a marine biologist?  Do internships!  This is the best way to get your name out there and to make connections with people who might be able to get you a job after college.  I had an internship at the NOAA Panama City Lab while I was in graduate school which helped me to get my job with NOAA when I graduated.

Kaci Heins: September 24-26, 2011

NOAA Teacher at Sea
Kaci Heins
Aboard NOAA Ship Rainier
September 17 — October 7, 2011

Mrs. Heins Acquiring Data For The Hydrographic Survey

Mission: Hydrographic Survey
Geographical Area: Alaskan Coastline, the Inside Passage
Date: Tuesday, September 27, 2011

Weather Data from the Bridge

Clouds: Overcast
Visibility: 10 Nautical Miles
Wind: 10.40 knots
Temperature
Dry Bulb: 11.3 degrees Celsius
Barometer: 1000.1 millibars
Latitude: 55.28 degrees North
Longitude: -133.68 degrees West

Science and Technology

I have received many questions from students asking “What is hydrography?”.  According to the International Hydrographic Organization,  hydrography is “the branch of applied science which deals with the measurement and description of the physical features of the navigable portion of the earth’s surface [seas] and adjoining coastal areas, with special reference to their use for the purpose of navigation.” Lets break that word down to find the meanings of the prefixes and suffixes using dictionary.com.

hydro – means water,

graph – means to write or chart

graphy – means the science or process of recording

Another question I have received is what is a hydrographic survey?  Most of the surveys that you may have heard of are used on land.  For example, construction workers may survey a site before they start construction, or you may take a survey at school about what types of food you would like in the cafeteria.  Any kind of survey is the acquiring of information that is used for various purposes.  In the case of a hydrographic survey, the technicians acquire and chart information about the sea floor.  I was fortunate enough to go out on a survey launch to see that a hydrographic survey is conducted using sonar to look through the water to see what the sea floor actually looks like.

Launch Boat

The boat that NOAA uses to conduct the surveys is called a launch.  This means we use a large motorboat to get to where we need to go.  It costs tens of thousands of dollars a day to operate the Rainier, her launches, and the technology.  It is the technology that allows scientists to be able to “see” through the water to map what the ocean floor actually looks like.  The first, and most important, piece of technology on the launch that enables us to “see” the sea floor is the sonar.  Sonar (SOund NAvigation and Ranging) is the process of using sound waves to bounce off objects we cannot see and then acquiring the return sound to create an image.  However, it does get a little more complicated than that.  There are two different types of sonar that the NOAA National Ocean Service (NOS) goes into detail about.

1) Active Sonar – Transmits a pulse or acoustic sound into the water. If the sound pulse hits an object in its path, such as the sea floor, then the sound bounces off  and returns an “echo” to the sonar receiver.  By determining the round-trip travel time between the emission of the sound pulse and its reception, the transducer can determine the range (how far away) and orientation (location) of the object.  The formula for this is

Distance = (two way travel time x speed of sound through water) / 2

2) Passive Sonar – Is a sonar system that does not emit its own signal, but listens to sound waves coming towards it.

Multibeam Sonar

Both the Rainier and the smaller launches have  both active sonar called multibeam sonar. Multibeam sonar sends out numerous sound waves from directly beneath the ship on the boat’s hull that fans out its coverage over the seafloor.  This coverage is called a “swath”.  Before we leave the ship to head out on the launches we have a briefing to go over the weather, safety, and any other important information for the coxswains, scientists, or crew.  We also get a plan for the day for what polygons, or areas we have to survey.  On our way we turn on some of the expensive (and top secret!) technology called the Position and Attitude System (POS).  This technology collects the vessels motion data (roll, pitch, and yaw), that later will be incorporated into the Caris software that produces the final chart. The multibeam transmits around 512

Polygon Coverage Area for the Day

beams each second.  The frequency of the sound waves depends on the depths that we are working in.  We worked in waters that were around 50 meters deep so we used the 400 kilohertz frequency.  However, if we would have been working in deeper water we would have gone to 200 kilohertz.  By lengthening the wavelength the beams can travel into deeper water with less error or scattering.

Before we start acquiring data we make sure to have good communication with the coxswain, or driver, of the boat.  It is extremely important that there is good communication and that the coxswain can maintain their heading and speed throughout the polygon so that the data can be collected without too many errors.

Conductivity, Temperature, and Depth Cast

We want to make sure we only go about 6-8 knots so that the sonar echo has time to make it back up to the receiver and we can collect good data.  The scientists also conduct a CTD cast before we start and every four hours while they collect data.  CTD stands for Conductivity (or salinity), Temperature, and Depth (pressure).  The data from the CTD can be used to calculate the speed of sound through water.  All of these factors can cause errors in the survey data so scientists need to collect this information so that the finished product has fewer errors and depths can be corrected from the sonar.  Other features that can cause errors in the data are bubbles, vegetation such as kelp, schools of fish, and the type of material that is on the sea floor.  For example, if the sea floor consists of a softer material it won’t reflect the sonar beams back as well.

To collect the survey data we basically drive the launch back and forth over our assigned polygons with the multibeam sonar.  This is sometimes called “mowing the lawn” or “painting the bottom”.  When we get to one edge of the polygon we stop logging data, turn around, and make a new swath as close as we can to the previous one and continue collecting data.  We cover around 50 nautical miles each day collecting data with the overall goal to collect the best data quality that we can during our acquisition.

As we head back to the Rainier all the computer data is downloaded from the day and is later transferred to the plot room.  This is where survey technicians add all the other information and make corrections to the data such as tides, vessel motion (POS), GPS, sound velocity from the CTD, and other programs so that the data is as accurate as possible.  Technicians still must go through and clean out “noise” which is scattering of some of the data.  The finished survey chart is sent to the Pacific Hydrographic Branch for post processing and quality assurance.

What We Surveyed Today!

Personal Log

In my last blog I wrote about how math skills are very important not only as a strong skill needed on a NOAA ship, but also as a life-long skill.  As I continue learning more about hydrography I have also found that computer skills are extremely valuable in this work environment.  Most people have basic computer skills to check email and run office programs, but out here it takes a little more.  There is quite a bit of training that the survey technicians and the NOAA Corps officers must go through to learn about all the different software that collects data and then using more software to combine them to make the finished hydro chart.  Numerous hours of collecting data, combining data, cleaning data and finishing projects all have a significant amount of work done by or at a computer.  Everyone from the captain to the junior officers must know how to use it and how to troubleshoot when things don’t work right.  It is not as easy as picking up the phone and calling customer service.  Minds among the ship must come together to solve problems when they arise.

Using the Computer to Collect Survey Data

While underway whether it is on the ship or on one of the launches the high seas are always around.  At first they made me nervous because I was afraid I would get sick.  However, it has turned out to be quite the opposite!  Whenever the seas get rough I actually start to get sleepy as we sway back and forth!  Usually, we are so busy that there isn’t time to take a nap so I’m learning to work through it.  Going along those lines of being busy, there are usually no breaks during the weekends.  In most people’s lives the weekend is time to take a break, hang out with family and friends, and sometimes do absolutely nothing at all.  Out here on a working ship this is not the case.  The NOAA ships have to meet certain deadlines and with some of their past major repairs, time has been ticking away with not much work being done.  This means when Saturdays and Sundays roll around at the end of the week we keep on working like a regular day.  I have the utmost respect for all of the crew, scientists, and officers that spend their time out here working for weeks straight.  It is not an easy lifestyle, but they are committed to it and I admire them and their strength.

Student Questions Answered

Wildlife Spotted!

Sea Otters

Humpback Whale

Sea Otter

Sea stars

Sea Urchins

Question of the day

Caroline Singler, August 13-15 2010

NOAA Teacher at Sea: Caroline Singler
Ship: USCGS Healy 

Mission: Extended Continental Shelf Survey
Geographical area of cruise: Arctic Ocean north of Alaska in the Canada Basin
Date of Post: 16 August 2010

Follow the Leader – 13 – 15 August 2010

Location and Weather Data from the Bridge
Date: 13 August 2010 Time of Day: 2100 (9:00 p.m.) local time; 04:00 UTC
Latitude: 73º0’N

Longitude: 145º3’W
Ship Speed: 3.9 knots

Heading: 1.8º (north)
Air Temperature: 2.0ºC/35ºF
Barometric Pressure: 1018.9 millibars (mb) Humidity: 100%
Winds: 3-5 Knots SW
Sea Temperature: -0.4ºC Salinity: 25.37 PSU
Water Depth:~3600 m

Ice with Ridges

Date: 14 August 2010

Time of Day: 2105 (9:05 p.m.)

local time; 04:05 UTC
Latitude: 73º36.4’N Longitude: 146º19.21’W
Ship Speed: 4.7 knots Heading: 223º (southwest)
Air Temperature: 2.15ºC/35.88ºF
Barometric Pressure: 1022.3 mb Humidity: 92.1%
Winds: 12.2 knots SE Wind Chill: -3.1ºC/26.5ºF
Sea Temperature: -0.7 ºC Salinity: 24.84 PSU
Water Depth: 3708.6 m

Open Water and Beautiful Sky

Date: 15 August 2010

Time of Day: 1500 (3:00 p.m.)

local time; 22:00 UTC
Latitude: 72º56.4’N

Longitude: 150º9.0’W
Ship speed: 11.8 knots

Heading: 220º (southwest)
Air Temperature: 5.6ºC/42.2ºF
Barometric Pressure: 1015.6 mb

Humidity: 98.1%
Winds: 17.7 knots E

Wind Chill: 1.7ºC/35.1ºF
Sea Temperature: 3.9ºC

Salinity: 24.5 PSU
Water Depth:3691.1 mScience and Technology Log

The Extended Continental Shelf Project is a multi-year effort between the United States and Canada. The two countries share knowledge, resources, and information to allow greater coverage of the region and more cost effective achievement of the mission objectives. For this mission, the USCGC Healy is working in tandem with the Canadian Coast Guard ice breaker Louis S. St. Laurent, called Louis(pronounced “Louie”) for short. Healy is responsible for collecting bathymetric data and shallow subsurface imaging while Louis performs deeper subsurface imaging with her air-gun array. The instrumentation on Louis is towed behind the ship and requires a clear path through the ice; therefore, Healy’s primary responsibility when the ships are in ice is to lead and break ice for Louis. Healy opens a path and Louis follows, typically about one to two miles behind depending on ice and visibility conditions. It was foggy for most of the day on Friday as we led the way north along the first track line. The only way I knew that Louis was behind us was by watching the ship tracking chart and listening to occasional radio chatter between the two boats as the crews communicated about ice conditions. Skies cleared as we moved farther north and deeper into the ice on Saturday. Near midday, the fog lifted and there was Louis, first emerging like a ghostly image out of the fog and then, as we made the turn onto a new transect line, she was in full view. By Sunday afternoon we were heading south in open water, so Healy moved away fromLouis to conduct other business while our ice breaking services were not needed.

USCGS Healy Leading USCGS Lewis

USCGS Louis on Ice

While multibeam sonar allows us to “see the bottom”, subbottom profiling uses a different sound-producing system to see what is under the bottom. Geologists use the subbottom data both from Healy andLouis to estimate sediment thickness and make inferences about sediment types and structures beneath the seafloor. It makes me think of Superman’s x-ray vision! Like multibeam sonar, subbottom profilers are echosounding devices. They are active sonar systems – sound signals are transmitted and received by the instrument.

Healy’s profiler is a “chirp” system mounted inside the bottom of the ship’s hull – so called because it sounds like a bird chirping, a sound that one hears in the background throughout the ship. It releases high frequency pulses of acoustic energy that travel through the water column and (in theory) hit the seafloor and penetrate into subsurface materials to depths of tens of meters. Signals are reflected at the seafloor and at interfaces between different subsurface layers within the seafloor. The reflection of acoustic energy depends on the “acoustic impedance” of the material encountered. Acoustic impedance is related to the density of the material and the velocity of sound in that medium. Different materials have different acoustic impedance and therefore different reflectivity. The concept is similar to that of albedo when one considers the reflection of solar energy from different surfaces. A smooth, light-colored surface like a field of snow reflects a high percentage of incoming solar rays and therefore has a high albedo– hence the glare that hurts your eyes on a sunny day. Dark-colored surfaces reflect much lower percentages of incident light and therefore have low albedo. (They also absorb more energy which is why they get hotter on a sunny day.)

With subbottom profiling, sands typically reflect sound differently than mud, and layers or other structures in the subsurface result in different signal strengths returning to the receivers on the ship. The picture on the right shows an image of the raw chirp data displayed on the computer screen at the watch stander station. It does not show a lot in this state, but after processing the data will provide important information about the subsurface in the Arctic Ocean.

Chirp Display

Subbottom surveying on Louis is performed with a multi-channel air gun system that is towed behind the ship. Three air guns, powered by air compressors on the ship’s deck, provide the acoustic energy source. A streamer with an array of 16 hydrophones trails behind the air guns; the hydrophones receive the return signals reflected by the seafloor and subsurface sediments. In open water, the air guns are attached to a float and hang about three to five meters below the surface, at a distance of about 100 meters behind the ship. In ice, the air guns are attached to a metal sled (depressor) that hangs below the sea surface (and hence the ice) to a depth of about 10 meters and at a distance of about 10 meters behind the ship. When fired, the air guns simultaneously emit large air bubbles into the water column. As the bubbles collapse, an acoustic pulse is produced that moves through the water. It is similar to what happens in the atmosphere when air rapidly expands and contracts as a lightning bolt passes through, creating the sound we know as thunder. The air guns generate sound at a lower frequency than the chirp system; sound at these lower frequencies penetrates deeper into the subsurface but produces lower resolution than the higher frequency chirp system. Such air gun systems can provide images to depths of several kilometers below the seafloor.

WHOI Subbottom Profiling Diagram

Image source: USGS Woods Hole Science CenterReferences:
USGS Woods Hole Science Centerhttp://woodshole.er.usgs.gov/operations/sfmapping/seismic.htm
NOAA Coastal Services Centerhttp://www.csc.noaa.gov/benthic/mapping/techniques/sensors/subbottom.htm

Personal Log
Saturdays are “Field Days” on Healy. No, we did not all get into boats and take a trip away from the ship or get out onto the ice. Field Day is a fancy way of saying that it is time for cleanup and inspection of common areas and personal berthing areas. All personnel on board are responsible for trash removal and cleaning of staterooms, restrooms and common living and working spaces. Anyone who is not on duty pitches in to clean the Science lounge and labs – vacuuming, sweeping, washing floors and generally putting things in order. The “trash vans” are open twice a week; everyone brings trash and recycling to two large blue bins on the port side of the 02 deck (the same deck as the science staterooms). Coast Guard volunteers work the trash vans. Healy will be at sea for another long mission after this one, so efficient trash removal and storage is critical. Healy personnel are dedicated to recycling and have an award winning recycling program on board – no small feat when it is necessary to haul it all around for months at sea. Think about that when you are tempted to complain about separating recyclables from trash at home or at school.

Since everything was neat and tidy, I decided it was a good time to show you my living space on Healy. Science staterooms are set up for three occupants, but on this trip we have two people per room. I share a room with Sarah Ashworth, a marine mammal observer; she is currently on Louis, so for now I have my own room. The room is more spacious than I expected on a ship, similar in size to a lot of college dorm rooms.

My Rack

Space is used very efficiently. There are bunk beds; Sarah has more experience at sea than I, so she has the top bunk or “rack”.

Bunks

Each person has a good sized locker for clothes and since there are only two of us, we each have a desk and filing cabinet, so there is plenty of storage space – more than we need for our personal belongings.

Sink and Locker

Desk Area

There’s nothing like a room with a view, even if they left the tape on the window the last time they painted the ship.

Sun on Water Through Porthole

Each room has its own sink, and shares a bathroom with the adjoining room. Okay, they call it a “head” on a ship; don’t ask me why! The bathroom is small, but one does not linger when taking a “sea shower”, and there is always plenty of hot water. In case you ever wondered what a marine toilet looked like, here it is.

Shower

Marine Toilet

We headed towards Barrow on Sunday to pick up a crew member and some supplies for the Louis. There was a steady wind from the east for most of the afternoon, and the boat was rolling a little, but I was more prepared for it this time than I was the first time it happened, but I still stumble when I walk down the hall.

We have had beautiful views of ice, sea, and sky for the last few days.

Ice with cool clouds

Waves and sky

Caroline Singler, August 3-4, 2010

NOAA Teacher at Sea:Caroline Singler
Ship: U.S. Coast Guard Cutter (USCGC) Healy

Mission: International Continental Shelf Survey
Geographical area of cruise: Bering Sea en route to Arctic Ocean
Date: 4 August 2010

In the Bering Sea – 3 & 4 August 2010

Location and Weather Data from the Bridge
Time of Day: 1600 (4:00 p.m.) local time; 00:00 UTC (Coordinated Universal Time)
Latitude: 65º19’N
Longitude: 168º16’W
Ship Speed: 16.9 knots Heading: 358.1º
Air Temperature: 11.33ºC /52.38ºF
Barometric Pressure: 1009.3 millibars Humidity: 94.9%
Winds: 9.6 Knots SSE
Sea Temperature: 9.9 ºC
Water Depth:53.6 m

Science and Technology Log

Since leaving Dutch Harbor on 2 August 2010, the USCGC Healy has traveled north through the Bering Sea en route to the Arctic Ocean, where we will embark on the third year of an international effort called the Extended Continental Shelf Project. In a few days, we will rendezvous with the Canadian Coast Guard Ship (CCGS) Louis S. St. Laurent in the Arctic Ocean. The objectives of this mission are to perform detailed bathymetric mapping of the seafloor and imaging of the subsurface and to collect physical seafloor samples in the part of the Arctic known as the Beaufort Sea and Canada Basin. I will write more about this over the next few days; in a nutshell, we want to determine the limits of the extended continental shelf in that region. Our primary role on the Healy is to serve as the lead ice breaker for the Louis so that she can collect multichannel seismic reflection data of the subsurface. At the same time, Healy will collect multibeam bathymetric data and high resolution seismic reflection data and obtain seafloor samples using a variety of dredging and coring methods. The extent of our work may be influence by sea ice conditions which can be unpredictable.One of my responsibilities on the cruise is to serve as a “Watchstander” for the geophysical data collection. Watchstanders work in pairs and are responsible for keeping an eye on the computer monitor displays of the data that is continuously collected by the multibeam sonar and “chirp” (seismic reflection) data and to call in the experts if something goes wrong. Water depths are shallow and the seafloor relatively featureless on our traverse through the Bering Sea, but the data will likely become more interesting when we reach out destination. This is the time to learn about the equipment and understand our responsibilities so that we’ll be sharp when our data collection efforts become more critical. Last year’s mission mapped a previously undiscovered seamount! My watch is from 2000 to 0000 (8 p.m. to midnight), which leaves me lots of time during the day to write, research, and wander around learning about the ship. Later in the mission I will be involved in the sampling efforts when I am not on geophysical watch.

Fog Bow

Personal Log
It has been smooth sailing since leaving Dutch Harbor, and we have moved relatively quickly, slowing occasionally when the fog thickens. Foggy conditions are common in the Bering Sea and Arctic Ocean. I went out on deck early yesterday evening to enjoy a brief period when the sun was visible above the fog, and was treated to the sight of a “fog bow”.

Puffin Check!

NOSB folks will be happy to know that my puffin is accompanying me on my journey, even when I’m on watch.

I’ve seen both horned puffins and tufted puffins from the ship, and I’m beginning to be able to tell the difference, but nothing beats the show the horned puffins put on for us in Dutch Harbor. If you want to see awesome bird shots, take a look at Bill Schmoker’s journals, which you’ll find linked on the upper right side of my blog page.

Earlier this afternoon, we passed near a small island called King Island in the northern Bering Sea. There was a lot of seabird activity closer to shore, and I was fortunate to be on the Bridge watching when the marine mammal observer saw a gray whale. I got to see it surface and dive once; no time for a photo, just firsthand enjoyment of the experience.


I took a break while writing this log to go back to the Bridge as we passed through the Bering Straits. The view was the same as it was for the rest of the day, but I wanted to have the best view in the house for the experience.

Moving through the Bering Strait

Today is Coast Guard Day which commemorates the formation of the Revenue Cutter Service in 1790. In honor of the occasion, the Coasties roasted a pig out on the helo (helicopter) deck and served a picnic style dinner in the Mess tonight.

Pig Roast

Did You Know?
I did a search to learn more about Coast Guard Day. According to the U.S. Department of Defense, the Treasury Department established the Revenue Cutter Service in 1790 and “authorized the building of a fleet of ten cutters, whose responsibility would be the enforcement of the first tariff laws enacted by Congress under the Constitution.” The name “Coast Guard” was adopted in 1915.
Source: U.S. Department of Defense