Frank Hubacz: Ice in the Bering Sea, May 7, 2013

NOAA Teacher at Sea
Frank Hubacz
Aboard NOAA ship Oscar Dyson
April 29 – May 10, 2013

Mission: Pacific Marine Environmental Laboratory Mooring Deployment and Recovery
Geographical Area of Cruise: Gulf of Alaska and the Bering Sea
Date: May 7, 2013

Weather Data from the Bridge (0500):
N wind 10 to 25kt. Partly cloudy.
Air Temperature 0.8C
Relative Humidity 90%
Barometer 1019.80 mb
Surface Water Temperature 2.30 C
Surface Water Salinity 31.96 PSU
Seas 4 to 9ft

Science and Technology Log

Remember that in my last blog you were left with a question…

Did you figure out what this was?
Did you figure out what this was?

If you still have not guessed what this is then here is a hint…


You are correct!  This is a Marine Assessment Monitoring and Prediction (MARMAP) Bongo tow with two 20cm and two 60 cm ring openings!  The 60 cm ring has a 500µm mesh net and the 20 cm ring has a 150µm.  I knew that most of you would guess the correct answer.  These nets are towed through the ocean to collect zooplankton samples. Plankton are important members of the ocean food web converting energy from the primary producer level into a form that is useable by animals in the upper levels of the marine food web. The word plankton is derived from the Greek word planktos, which means wandering.  Plankton drift, or swim weakly, traveling wherever the ocean takes them.  Phytoplankton are able to produce their own food (autotrophic), as the name suggests, via the process of photosynthesis. Zooplankton are heterotrophic and eat the primary producers in the ocean food web, the phytoplankton.  Zooplankton are the most numerous consumers in the entire ocean with nearly every major animal group being represented.   The most abundant, accounting for 70% of individuals, are copepods (crustaceans).  You are all probably most familiar with the organism within this group known as krill.  They are very abundant in the waters of the Arctic.


These shrimp-like marine organisms grow no larger than 4 to 6 cm and serve as food for baleen whales, penguins, seals, fish, sea birds, and many other predators.  80(+) species of krill have been identified in oceans around the world. Their habitats range from abyssal depths (5,000 m) to near shore kelp beds (10 m), and from warm tropical seas to the freezing Antarctic Ocean. (

Marine scientist use bongo nets to catch these small creatures and study them. The net size is selected to catch zooplankton as opposed to smaller phytoplankton.  The bongo net has a flow meter installed in each net to calculate the volume of water sampled.   Plankton tows can be done at any depth or time of day and the samples are caught in a small rigid container, the codend.

Basic Bongo tow
Detailed Bongo schematic


Cod-end of  Bongo tow net
Codend of Bongo net where the sample is collected
Our night shift deploying our Bongo net
Our night shift readying our Bongo net
Deploying the Bongo net in dark icy waters of the Bering Sea
Retrieving the net after the tow
Matt washing the contents of the codend into a straining sieve
Matt washing the contents of the codend into a straining sieve
Capturing all of the sample
A closer look!
A closer look!

The Bongo tow used on this cruise also has attached an SBE-19 SEACAT system which measures salinity, depth, and temperature.

SEACAT System attached to Bongo tow
SEACAT System (on right) attached to Bongo tow

Additionally deployed on this cruise were drogue drifters.  Drogue drifters help determine the flow of ocean currents using a sort of “message in a bottle” approach, the drogue drifter, which is connected to a surface buoy.  The buoy communicates its location to an ARGOS satellite system producing a map of its path.  The drogue portion is really a “holey-sock” that flows below the surface to indicate subsurface ocean currents.

Drifter Schematic
Complete drifter package
Bill preparing the drogue drifter for launch
Drogue drifter entering the water with attached satellite buoy
World map of current drifter locations


Overnight on the 7th we turned north-north-west hoping to sample water near the edge of the ice sheet.  We found ice much earlier than hoped and at approximately 0630 a decision was made that we could travel no further!  Upon collecting a sample at this station we turned south to sample along the 70 meter line for several miles.

Ice flow...picture taken at 0300
Ice flow…picture taken at 0300
Ice all around
Ice all around


Ice as seen from the bridge(Photo courtesy of Matt Wilson)

Ice as seen from the bridge(Photo courtesy of Matt Wilson)
Saying good bye to the ice!
Saying good bye to the ice!(Photo courtesy of Matt Wilson)

Personal Log

Sampling continues around the clock now that all of the moorings have been deployed.  I continue to collect nutrient samples from each CTD launch, usually 5 to 7 per draw, assist with washing the Bongo nets, and helping wherever I can .  Our midnight to noon shift goes by quickly.  After my shift I have been relaxing by reading and then going to bed by 0300 before waking at 2300.  Now that we are heading south our satellite “issues” have been resolved and so the internet works great.  Keep those questions coming.

We had an abandon ship drill today and I finally was able to “slip” into my Survivor Suit!  You will get to meet the science crew in my next blog!

Slipping into my survival suit
Slipping into my survival suit
Heading for the life boat station
Heading for the life boat station
Arriving at the WRONG station!
Arriving at the WRONG life boat station! (Port is left)

Natalie Macke, August 25, 2010

NOAA Teacher at Sea: Natalie Macke
NOAA Ship: Oscar Dyson
Mission:  BASIS Survey

Geographical area of cruise: Bering Sea
Date: 8/25/2010
The Sounds of Science…
Weather Data from the Bridge :
Visibility :  10+ nautical miles (Wondering what a nautical mile is??)
Wind Direction: From the ESE at 8 knots
Sea wave height: <1ft
Swell waves: NW, 1-2 ft
Sea temp:6.8 oC
Sea level pressure: 1018.1 mb
Air temp: 8.2 oC
Science and Technology Log: 
Acoustician, Sandra Parker-Stetter on the Bridge preparing to fish..

When you walk into the acoustics lab you are greeted with an impressive display of primary colors and fascinating images.  Sandy, our Acoustician is also there to greet you and help explain the science behind the images of sound.  She explained not only the basics of acoustic science; but also shared some fascinating biological phenomena that can be witnessed with this technology.

So first some basics about the acoustics.  (Hoping BTW to make Sandy proud about her skills in teaching a physics phobic..   She only made my head hurt a few times..)  When you walk in the Acoustics Lab on the Oscar Dyson you will see there are six different acoustic displays in the lab:

  • 18 kHz & 38 kHz on one display  (These are more common to fishing vessels to distinguish larger fish from jellies, zooplankton and juvenile fish)
  • 70 kHz, 120kHz, 200kHz and a 70 kHz with a sideway view from the ship.

The acoustic sounders positioned on the ship’s centerboard emit a ping that is transmitted directly downward from the boat (except one 70kHz pointed sideways).

These pings each have a set characteristic frequency designated by the unit of a kiloHertz (kHz).   A  kilohertz simply is the thousands of cycles per second that the wave is transmitted.  Frequency is indirectly related to wavelength.  So if you think about what will fit in-between the waves in the left image it will make sense that lower frequency acoustics are used to identify larger things, while higher frequency captures images of much smaller species or individuals.

Acoustics have the potential to not only identify schools of fish, but also discriminate between species types as well.  A characteristic scattering is observed from different types of fish depending on their internal structure (morphology) and composition.  For example, whether or not a fish has a swimbladder can be used for identification.  A swimbladder will cause a greater acoustic scattering.  In terms of composition, jellyfish are over 99% water.  The more like the composition of water, the less the sound bounces off the specimen.  Therefore, the scatter from the ping of the acoustics is weak and difficult to see on the monitor.   However, the jellyfish signature is shows up quite strong on the acoustic monitors.  In this case, the size and shape of the jellyfish causes the sound to scatter regardless of its’ composition.  So acoustic analysis is not always as straight-forward as the scientists (and fishermen) would like.  So how do the scientist tell a jellyfish from a juvenile salmon?  Trawling data..   Part of the acoustic’s mission on our BASIS cruise.  The scientists would like to develop patterns to match trawls with acoustic signals.  Therefore, acoustics can be used in the future more effectively to track and monitor pelagic populations.

 Biological Phenomena Visualized with Acoustic Technology
Biological Phenomena Visualized with Acoustic Technology

Zooplankton Migration 
Using the 200kHz acoustics, tracking the movement of the zooplankton is quite easy.  In the image to the left, taken and archived during the evening hours you can literally see how the zooplankton migrate toward the ocean surface as the sun sets(Around 10PM in these parts..).   Trying to avoid their predators, the zooplankton stay near the ocean bottom during the daylight hours, but migrates upward toward their food source, the phytoplankton, once darkness begins to onset.

Riding the Pycnocline
Another interesting physical oceanographic feature you can observe with acoustics is the pycnocline.  While you can’t literally see the density change of the water using the acoustics aboard this ship, you can watch the fish hover immediately above this feature.

18 kHz Acoustics
38 kHz Acoustics

Personal Log:


Yesterday morning’s sunrise was one for the books..  Tuesday was a glorious, sunny day aboard the Dyson.. (Uh..  the answer is YES..  apparently Alaskans do sunbathe in 50 degree weather.  As long as the sun is out…  I won’t mention any names.)  The daytime turned to an evening with a sky full of stars.  We then were treated to a spectacular sunrise the next morning with beautiful calm seas.  Thanks to Sandy, who captured the picture to the left that morning, while most of us were busy eating omelets and pancakes in the Mess Hall.

It’s fun sometimes when Sandy’s right….

Brian Beckman, Fish Biologist

After days of searching for the juvenile salmon, we finally found their playground.  One of trawls yesterday brought us over 2,000 sockeye juveniles along with a mess of jellies…  After accosting my colleagues with a few paparazzi moments, it was fun to join in to help sort out the catch.   And even sometimes when things don’t work out perfectly, finding what you’re looking for makes everything better. To the right is a snapshot of what happens when the bin doesn’t stop in time and the fish/jelly mess overtakes the belt and scientists.  Now this is fishin’….

“Catch of the Day…”