Britta Culbertson: The Beat of the Bongo (Part 1): Catching Zooplankton, September 11, 2013

NOAA Teacher at Sea
Britta Culbertson
Aboard NOAA Ship Oscar Dyson
September 4-19, 2013

Mission: Juvenile Walley Pollock and Forage Fish Survey
Geographical Area of Cruise: Gulf of Alaska
Date: Wednesday, September 11th, 2013

Weather Data from the Bridge (for Sept 11th, 2013 at 10:57 PM UTC):
Wind Speed: 4.54 kts
Air Temperature: 10.50 degrees C
Relative Humidity: 83%
Barometric Pressure: 1009.60 mb
Latitude: 58.01 N              Longitude: 151.18 W

Science and Technology Log

What is a bongo net and why do we use it?

As I mentioned in a previous entry, one of the aspects of this cruise is a zooplankton survey, which happens at the same stations where we trawl for juvenile pollock.  The zooplankton are prey for the juvenile pollock.  There are many types of zooplankton including those that just float in the water, those that can swim a little bit on their own, and those that are actually the larval or young stage of much larger organisms like crab and shrimp.  We are interested in collecting the zooplankton at each station because because we are interested in several aspects of juvenile pollock ecology, including feeding ecology.  In order to catch zooplankton, we use a device called a bongo net.  The net gets its name because the frame resembles bongo drums.

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Diagram of a 20 cm bongo net set-up. (Photo credit: NOAA – Alaska Fisheries Science Center)

The bongo net design we are using includes 2 small nets on a 20 cm frames with 153 micrometer nets attached to them and 2 large nets on 60 cm frames with 500 micrometer nets.  The 500 micrometer nets catch larger zooplankton and the 153 micrometer nets catch smaller zooplankton.  In the picture above, there are just two nets, but our device has 4 total nets.  At the top of the bongo net setup is a device called the Fastcat, which records information from the tow including the depth that bongo reaches and the salinity, conductivity, and temperature of the water.

Bongo in water

This is what the bongo looks like when it’s finally in the water (Photo credit: John Eiler)

What happens during a bongo net tow?

The process of collecting zooplankton involves many people with a variety of roles.  It usually takes three scientists, one survey tech, and a winch operator who will lower the bongo net into the water.  In addition, the officers on the bridge need to control the speed and direction of the boat.  All crew members are in radio contact with each other to assure that the operation runs smoothly.  Two scientists and a survey tech stand on the “hero deck” and work on getting the nets overboard safely.  Another scientist works in a data room at a computer which monitors the depth and angle of the bongo as it is lowered into the water.  It is important to maintain a 45 degree angle on the wire that tows the bongo to make sure that water is flowing directly into the mouth opening of the net.  One of the scientists on the hero deck will use a device that we lovingly call the “frying pan,” but more accurately it is called a clinometer or inclinometer. The flat side of the device gets lined up with the wire and an arrow dangles down on the plate and marks the angle.  The scientist calls out the angle every few seconds so that the bridge knows whether or not to increase or decrease the speed of the ship in order to maintain the 45 degree angle necessary.

Peter and the pan

Scientist Peter Proctor holds up the “frying pan” also known as a clinometer or inclinometer, which is used to measure the wire angle of the bongo when it’s in the water.

Meanwhile, back at the computer, we monitor how close the bongo gets to the bottom of the ocean.  We already know how deep the ocean is at our location because of the ship’s sonar.  The bongo operation involves a bit of simple triangle geometry.  We know the depth and we know the angles, so we just have to calculate the hypotenuse of the triangle that will be created when the bongo is pulled through the water to figure out how much wire to let out.  The survey tech uses a chart that helps him determine this quickly so he knows what to tell the winch operator in terms of wire to let out.  In the images below, you can see what we are watching as the bongo completes its tow.  The black line indicates the depth of the bongo, and the red, purple, and blue lines indicate temperature, conductivity, and salinity.

Good bongo tow

This is an example of a good bongo tow. The black line on the left of the graph shows a consistent tow angle both up and down. The key is that the black line should have a “v” shape on the graph if the tow is good.

Bad bongo

This graph shows what happens when a bongo gets caught in the current and stays at the same depth for a while. Look at how the black line isn’t smooth, but levels off for a bit. This happened with the bongo both when it was going down and coming back up to the surface.

When the bongo is within in 10 meters of the bottom, the survey tech radios the winch operator to start bringing the bongo back up.  It usually takes longer for it to come up as it does for it to go out, nevertheless, the 45 degree wire angle needs to be maintained.  When the survey tech sees the bongo at the surface of the water, the two scientists on the hero deck get ready to grab it.  This operation can be quite difficult when it’s windy and the seas are rough. If you look at the sequence of the photos below, pay attention to the horizon line where the water meets the sky and you can get a sense of the size of the swells that day.

When the bongo is safely back on deck, the person in the data room records the time of the net deployment, how long it takes to go down and up, how much wire gets let out, and the total depth at the station.  If anything goes wrong, this is also noted in the data sheet.

As the bongo reaches the surface, the scientists grab the net keep it from banging into the side of the ship.  When the net is on board, the next step is to read the flowmeters on the nets that indicate how much water has flowed through them.  Then we rinse the nets and wash all of the material down the nets and into the “codends” at the very end of the net.  These are little containers that can be detached and emptied to collect the samples.

Once the codends are detached, they are taken to the wet lab and rinsed.  Each of the four parts of the net has a codend where the zooplankton are caught. The zooplankton are rinsed out of the codends into a sieve and then collected in a jar and preserved with formalin.  The purpose of having two of each of the 20 cm and 60 cm bongo nets is to ensure that if one sample is bad or accidentally dumped, there is always a backup.  I have had to use the backup once or twice when there was a big jellyfish in the codend that kept me from getting all of the zooplankton out of the sample.

Codend

The codend from the 150 micrometer bongo net.

cleaning the codends and sieve

Britta rinsing the 500 micrometer sieve.

After we collect the zooplankton the samples are shipped to Seattle when we return to port. Back in the labs, the samples are sorted, the zooplankton are identified to species, and the catch is expressed at number per unit area.  This gives a quantitative estimate of the density of plankton in the water.  A high density of the right types of food means a good feeding spot for the juvenile walleye pollock!  This sorting process can take approximately one year.  I think it’s pretty amazing how much work goes into collecting the small samples we get at each station.  Just to think of all of the person hours and ship hours involved makes me realize how costly it is to study the ocean.

Colleen and zooplankton jar

Scientist Colleen Harpold holding up one of the preserved jars of zooplankton.

Colleen with zooplankton

Scientist Colleen Harpold holding up one of the preserved jars of zooplankton that has A LOT of algae in it too!

Personal Log

It is hard to believe that I’ve been on the ship a week now.  It feels strange that just 7 days ago I had never heard of a bongo net or an anchovy net.  Now I see them every day and I know how to identify several types of fish, jellyfish, and zooplankton.  I love working with the scientists and learning about the surveys we are doing.  Nearly every trawl reveals a special, new organism, like the Spiny Lumpsucker – go look that one up, I dare you!  We don’t have much down time and I’m trying to blog in between stations, but sometimes the time between stations after we finish our work can be 45 minutes and sometimes just 15 minutes.  So we are pretty much on the go for the whole 12-hour shift.  That’s where the fortitude part of Teacher at Sea comes in.  You definitely need to have fortitude to endure the long hours, occasional seasickness (I like to think of it as “sea discomfort”), and periodic bad weather.

By now though, it all seems routine and I’d like to think I’ve gotten used to being thrown around in my sleep a little now and again when we hit some rough seas.  This experience has been so worthwhile and even though I look forward to the comforts of home, I don’t really want it to end.  When I graduated from college, I worked with a herpetologist studying lizards in the desert south of Carlsbad, New Mexico.  I have fond memories of living in a tent for four months and collecting lizards all day to bring back to camp to measure and check for parasites.  I often miss doing scientific work, so Teacher at Sea has given me the opportunity to be a scientist again and to learn about a whole new world in the ocean.  What a treat! One of the reasons I chose to be a teacher was to be able to share my excitement about science with students and I feel so lucky that I get to share this experience too.

Did you know?

There are two species of Metridia, a type of copepod (zooplankton), that are found in the Gulf of Alaska/Bering Sea.  One of them is called Metridia lucens and the other one is Metridia oketensis.  These copepods are bioluminescent, which means that they glow when they are disturbed.  They sometimes glow when they are in the wake of the ship or on the crest of a wave.  Tonight when I was draining a codend into a sieve, my sieve looked like it had blue sparkles in it, but just for a second!  I asked our resident zooplankton expert, Colleen Harpold what they might be and she thought that my blue sparkles likely belonged to the genus Metridia.

If you are interested in reading a little more about Metridia, check out this blog from Scientific American on copepods in the Bering Sea!

Metridia longa

This is an image of Metridia longa. (Photo credit: NOAA/Hopcroft)

Glowing Metridia

This is a picture from Scientific American of Metridia spp. glowing while in a sieve. (Photo Credit: Chris Linder, Woods Hole Oceanographic Institute)

 Thanks for reading! Please leave me some comments or ask questions about any of the blog posts and feel free to ask other questions about the work we are doing or what it’s like at sea! I would love to be able to answer real-time while I am at sea.

Sue Cullumber: Drifting Away, June 21, 2013

NOAA Teacher at Sea
Sue Cullumber
Onboard NOAA Ship Gordon Gunter
June 5–24, 2013

Mission: Ecosystem Monitoring Survey
Date: 6/21/2013
Geographical area of cruise:  The continental shelf from north of Cape Hatteras, NC, including Georges Bank and the Gulf of Maine, to the Nova Scotia Shelf

Weather Data from the Bridge:  Time:  21.00 (9 pm)
Latitude/longitude:  3734.171ºN, 7507.538ºW
Temperature: 20.1ºC
Barrometer: 1023.73 mb
Speed: 9.6 knots

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Getting ready to launch the buoy – photo by Chris Taylor.

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Launching the buoy from the ship’s stern – photo by Chris Taylor.

Science and Technology Log: 

This week we launched a Global Drifter Buoy (GDB) from the stern of the Gordon Gunter.  So what is a GDB? Basically it is a satellite tracked surface drifter buoy.  The drifter consists of a surface buoy, about the size of a beach ball, a drogue, which acts like a sea anchor and is attached underwater to the buoy  by a 15 meter long tether.

Drifter tracking: The drifter has a transmitter that sends data to passing satellites which provides the latitude/longitude of the drifter’s location. The location is determined from 16-20 satellite fixes per day.  The surface buoy contains 4 to 5  battery packs that each have 7-9 alkaline D-cell batteries, a transmitter, a thermistor to measure sea surface temperature, and some even have other instruments  to measure barometric pressure, wind speed and direction, salinity, and/or ocean color. It also has a submergence sensor to verify the drogue’s presence. Since the drogue is centered 15 meters underwater it  is able to measure mixed layer currents in the upper ocean. The drifter has a battery life of about 400 days before ending transmission.

buoy

Stickers from students at Howard Gray School.

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Attaching the stickers to the buoy – photo by Kris Winiarski.

Students at the Howard Gray School in Scottsdale, Arizona designed stickers that were used to decorate the buoy. The stickers have messages about the school, Arizona and NOAA so that if the buoy is ever retrieved this will provide information on who launched it.  In the upcoming year students at Howard Gray will be tracking the buoy from the satellite-based system  Argos that is used to collect and process the drifter data. You can follow our drifter here, by putting in the data set for the GTS buoy with a Platform ID of 44932 and select June 19, 2013 as the initial date of the deployment.

Why are drifter buoys deployed?

In 1982 the World Climate Research Program (WCRP) determined that worldwide drifter buoys (“drifters”) would be extremely important for oceanographic and climate research. Since then drifters have been placed throughout the world’s oceans to obtain information on ocean dynamics, climate variations and meteorological conditions.

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The Howard Gray School drifter on its ocean voyage.

NOAA’s Global Drifter Program (GDP) is the main part of the Global Surface Drifting Buoy Array, NOAA’s branch of the Global Ocean Observing System (GOOS).  It has two main objectives:

1. Maintain a 5×5 worldwide degree array (every 5 degrees of the latitude/longitude of world’s oceans) of the 1250 satellite-tracked surface drifting buoys to maintain an accurate and globally set of on-site observations that include:  mixed layer currents, sea surface temperature, atmospheric pressure, winds and salinity.

2. Provide a data processing system of this data for scientific use.

bongossunset

Bongo nets going out for the plankton samples.

meshsamples

Plankton from the different mesh sizes. The left is from the smaller mesh and contains much more sample. Photo by Paula Rychtar.

EcoMon survey: We are continuing to take plankton samples and this week we started taking two different Bongo samples at the same station. Bongo mesh size (size of the holes in the net) was changed several years ago to a smaller mesh size of .33 mm. However, they need comparison samples for the previous nets that were used and had a mesh size of about .5 mm.  They had switched to the smaller net size because they felt that they were losing a large part of the plankton sample (basically plankton were able to escape through the larger holes). We are actually able to see this visually in the amount of samples that we obtain from the different sized mesh.

dolphinflying

Common Dolphins were frequent visitors to the Gordon Gunter.

Personal Log:

It’s hard to believe that my Teacher at Sea days are coming to a close. I have learned so much about life at sea, the ocean ecosystem, the importance of plankton, data collection, and the science behind it all.  I will miss the people, the ocean and beautiful sunsets and the ship, but I’m ready to get back to Arizona to share my adventure with my students, friends and family. I want to thank all the people that helped me during this trip including: the scientists and NOAA personnel, the NOAA Corps and ship personnel, the bird observers and all others on the trip.

Did you know? Drifters have even been placed in many remote locations that are infrequently visited or difficult to get to through air deployment.  They are invaluable tools in tracking and predicting the intensity of hurricanes, as well.

Question of the day?  What information would you like to see recorded by a Global Drifter Buoy and why?

shipsunset-2

Another beautiful sunset at sea.

Sue Cullumber: Plankton, Food for the Sea! June 13, 2013

NOAA Teacher at Sea
Sue Cullumber
Onboard NOAA Ship Gordon Gunter
June 5–24, 2013

Mission: Ecosystem Monitoring Survey
Date: 6/13/13
Geographical area of cruise:  The continental shelf from north of Cape Hatteras, NC, including Georges Bank and the Gulf of Maine, to the Nova Scotia Shelf

Weather Data from the Bridge:  Time:  8:25 am
Latitude/ Longitude:  4200.0122N, 6758.0338W
Temperature:  12.4ºC
Barometer:  1007.26mb
Speed:  9.1 knots

Science and Technology Log:

Why study plankton?  Plankton are at the bottom of the food chain. Remember they are free floating organisms that drift with the currents. That means that they provide food for many other animals and those animals are then eaten by larger animals and so on.  Therefore, plankton are important in the fact that if something happens to them, then the whole food chain is affected.

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Scientist, Chris Taylor, and Fisherman, Cliff Ferguson, bring the Bongo net back onto the ship.

So researchers are interested in learning all about the different types of plankton, their distribution and abundance in the ocean.  They want to answer questions such as: Have these factors changed over time?  Are we finding different kinds of plankton in different locations?  Has the amount of plankton changed?  How do the changes in the abundance and species of plankton affect higher trophic (feeding) levels?

Types of Plankton:

phaeocystis-phytoplankton

Phytoplankton on the surface of the water.

Phytoplankton – The plants of the sea. They carry out photosynthesis, so they are found in the water column where light is able to reach. This can vary depending on how clear the water is.  If water is very clear, they can be found at deeper levels because the light can penetrate farther.  These are the primary producers of the ocean, providing food for the first order consumers – mainly some types of zooplankton.

Amphipods, the two larger organims, and Copepods, the pink organisms– some of the many types of zooplankton we are finding.

Zooplankton – Animal-like plankton.  These vary immensely by size, type, and location. They are classified by their taxonomy, size, and how long they stay planktonic (some only are planktonic in a larval stage where others are for their entire life) .  These plankton are consumers with some eating the phytoplankton and others eating other zooplankton. These are extremely important as larger consumers eat them and then even larger organisms eat these.

fishlarvae

Fish larvae in among some copepods.

Icthyoplankton – Fish larvae or eggs. These float and drift in the water and, therefore, are considered planktonic.  Since these are only planktonic for part of their life, they are called meroplankton.  Organisms that are planktonic their entire life are called holoplankton.

Vocabulary:

Plankton – free floating organisms that drift with the current.

Trophic level – position an organism occupies in the food chain.

Taxonomy – how scientists classify organisms.

Holoplankton – organisms that are planktonic their entire lives.

Meroplankton – organisms that are planktonic for only part of their lives.

I interviewed our lead scientist onboard the Gordon Gunter who studies plankton:

chrismelrose

Lead Scientist – Chris Melrose

Name: Chris Melrose

What is your Position? Research Oceanographer

What do you do?  Principal investigator on  the Northeast Fisheries’ Ship of Opportunity project.  We collect data from merchant vessels that are crossing areas that we are interested in. I also work on the Ecosystem Monitoring Surveys where my main area of interest is primary production and phytoplankton. They are the base of the food web and tell you a lot about the functioning of a marine ecosystem.  Much of my work was in coastal regions where there were concerns about eutrophication, the enhanced primary production due to inputs of nutrients from pollution.

Why is your work so important?  We are studying the planet we all live on and we are in a period of environmental change. Long term monitoring programs, like this one, allow us to compare data from the present with the past to see how things have changed and also helps us to make predictions about what will happen in the future.

Why did you decide to become a marine scientist and work with NOAA and ocean science?  I grew up on the island of Martha’s Vineyard and always had an interest in the ocean. It was a hobby, but now it’s a career.

What do you enjoy most? I like science and being able to be out in the field – it is more of an adventure than just being in a lab.

What part of your job is most unexpected? When you are out in the ocean, there are always surprises – nature, weather or difficulties with ships, so you always have to be ready to adapt.

How long have you worked for NOAA and as a marine scientist?  From 1998 to 2004 I was with NOAA as a graduate student, from 2004 to 2010 as a contract employee and in 2011 I became a full-time employee.

What is your favorite type of plankton?  Diatoms because they have so many different shapes and geometric designs.

What is your favorite marine animal? Octopus as they are clever and it is amazing how they can change their color and shape.

If a student is interested in pursuing a career in marine science, what would you suggest to them?  Science and math are very important and you would need to attend graduate school.

What type of education do you need? At least a master’s degree to become a research scientist.

suewithbongos

Spraying down the Bongo nets – photo by Chris Melrose.

Personal Log:  

I am now getting use to my shift, noon to midnight.  At each station we put out the Bongo nets or Rosettes (more often the Bongos) and then we have to wash them down and strain out the plankton in a sieve to be saved later for the research. It gets a little harder and colder towards the end of the shift, but it has been very interesting seeing all the variety of plankton we are finding and how it changes from station to station.

stormwave2

Waves were a little higher during a very foggy day on the Gordon Gunter.

Yesterday was very foggy and a little more rocky.  It was very hard to see anything, but still beautiful to look at the ocean around us.  Today it is clearer, but still somewhat rocky.  Sightings have been few, but we were able to catch some whales in the distance by seeing them “blow” – spirt out water through their blow holes.  A Storm is on the forecast and we have had to change our route. We will not be going as far east as planned and will head north to avoid the main barrage of the storm.

The ocean is such an amazing place, with all its life and vastness. It makes you realize just how small you are and how big the world really is!

oceansunsetshipgood

Sunset off the stern of the Gordon Gunter.

zooplank

Euphausid- commonly known as krill

Did you know? Many types of whales feed exclusively on euphausid (or krill), a shrimp like zooplankton.

Question of the Day: What is your favorite type of plankton?

Sue Cullumber: Hooray, We Are Finally on Our Way! June 10, 2013

NOAA Teacher at Sea
Sue Cullumber
Onboard NOAA Ship Gordon Gunter
June 5–24, 2013

Mission: Ecosystem Monitoring Survey
Date: 6/10/13
Geographical area of cruise:  The continental shelf from north of Cape Hatteras, NC, including Georges Bank and the Gulf of Maine, to the Nova Scotia Shelf

Weather Data from the Bridge:
Time:  21:30 (9:30 pm)
Longitude/latitude: 40.50289N, 68.76736W
Temperature  14.1ºC
Barrometer 1017.35 mb
Knots  10.2

sueleavingport

Leaving Newport – photo by Chris Melrose.

Science and Technology Log:

After several ship issues, we were able to finally head out from Newport, RI on June 9th after 4 extra days in dock.  We have started the survey and are using two main types of equipment that we will deploy at the various stations: CTD/Bongo Nets and CTD Rosette Stations.  We were originally scheduled to visit about 160 stations, but due to the unforeseen ship issues, these may have to be scaled back.  Some of the stations will just be the Bongo and others only the Rosette, but some will include both sets of equipment.

Bongos

Bongo and baby bongos being deployed during the survey.

A bongo net is a two net system that basically, looks like a bongo drum.  It is used to bring up various types of plankton while a CTD is mounted above it on the tow wire to test for temperature, conductivity and depth during the tow. The two nets may have different sizes of mesh so that it will only  filter the various types of plankton based on the size of the holes.  The small mesh is able to capture the smaller phytoplankton, but the larger zooplankton (animals) can dart out of the way and avoid being captured. The larger mesh is able to catch the zooplankton but allows the phytoplankton to go through the openings. There are regular bongo nets and also baby bongo nets that may be launched at the same time to catch different types of plankton.

rosetteinwater

Rosette CTD returning to the surface.

The Rosette CTD equipment is a series of 10 cylinders that can capture water from different depths to test for nutrient levels and dissolved inorganic carbon, which provides a measure of acidity in the ocean. These are fired remotely via an electronic trigger that is programed by a computer program where each cylinder can be fired seperately to get 10 samples from different depths.  It also has several sensors on it to measure oxygen, light and chlorophyll levels, as well as temperature and salinity (salt) from the surface to the bottom of the water column.

plankton

Copepods and Krill from one of the bongo net catches.

Our first station was about 3 1/2 hours east of Newport, RI and it was a Bongo Station.  I am on the noon to midnight shift each day.  So on our first day, during my watch, we made four Bongo stops and two CTD Rosettes. Today we completed more of the Bongos on my watch.  We are bringing up a variety of zooplankton like copepods, ctenophores, krill, and some fish larvae.  We have also seen quite a bit of phytoplankton on the surface of the water.

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Wearing the survival suit – photo by Cathleen Turner.

Personal Log:

Being on a ship, I have to get used to the swaying and moving about.  It is constantly rocking, so it can be a little challenging to walk around.  I have been told that I will get used to this and it is actually great when you want to go to sleep!  Luckily I have not had any sea sickness yet and I hope that continues!  We completed several safety drills that included a fire drill and abandon ship drill where we had to put on our survival suits – now I look like a New England Lobster!

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Common dolphins swimming off the ship’s bow.

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Blue shark swimming beside the Gordon Gunter.

Today was an amazing day – was able to see Right Whales, Blue Sharks and Common Dolphins – with the dolphins surfing off the ship’s bow!  The Northern Right Whale is one of the most endangered species on the planet with only 300 left in the wild.  One of the reasons there are so few left is that swim on the surface and were excessively hunted and there feeding areas were within the Boston shipping lanes, so they were frequently hit by ships. Recently these shipping lanes have been moved to help protect these animals.  So I feel very privileged to have been able to see one!

Did you know? Plankton are the basis for the ocean food web.  They are plentiful, small, and free floating (they do not swim). The word plankton comes from the Greek word “planktos” which means drifting. “Plankton” from the TV show SpongeBob is actually a Copepod – a type of zooplankton.

Copepod

Copepod

Question of the day:  Why do you think it is important that the scientists study plankton?

Kaitlin Baird: Some Essential Tools! September 14, 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 North East Fisheries  Science Center
Geographical Area: Off the Coast of Cape Hatteras, North Carolina
Date: September 14th
.

Location Data:
Latitude: 35′ 10.67
Longitude:  75’33.60     

Weather Data:
Air Temperature: 23.40 (approx.74 °F)
Wind Speed: 2.17 kts
Wind Direction:  Southwest
Surface Water Temperature:2 7.61 °C (approx. 82°F)
Weather conditions: Sunny and fair

Science and Technology Log

One of the things I was curious about was the deployment of these large instruments and the technology that supports it. One of the keys to the deployment of things like the BONGO nets, Continuous Depth Recorders (CTD’s) and the trawl net itself are winches. A winch spools the wire cable that is hooked to all of the instruments and allows them to move up, down and out into the water column. With some of the instruments, like the BONGO’S and CTD casts, a retractable A-Frame is used to lower the cable from the winch. You can see the A-Frame on the right and the winch on the left in the photo below. This winch in particular controls the deployment of the net and connects to two winches on the stern that roll out the net to open up the mouth. The wire is constantly monitored from the bridge on the screen below and is automatically adjusted to maintain equal tension on both sides.

Winch for fishing nets, Tension monitor on winches from the bridge and A-frame

Winch for fishing nets, Tension screen for winches from the bridge and retractable A-frame

Once the net is run out with the aid of the winches, it is constantly monitored for its shape during the tow with a number of different censors attached to the net. There is an autotrawl system that sets the depth of the trawl and the tension of the wires. A Global Positioning System (GPS) plots the position of the net for each trawl so that it can be associated with all organisms caught in the tow. At the end of the tow the winches reel back the cable and a crane brings the net with the catch over to the “checker” where the net is unloaded!

Monitoring the position and shape of the trawl in the water

Monitoring the position and shape of the trawl in the water

Personal Log:

The fun part begins when the net opens and all the animals enter the checker. When all of the catch goes into the checker the scientists take a look at the catch, and remove anything too large to go up the conveyor belt. If a fish dominates the catch it will “run”. This means, as it goes down the conveyor belt it won’t be taken off and it will be weighed by the basketful and then a subsample will be taken for further analysis.

The fish are all divided up by species and electronically coded in the FSCS system to be measured. After they are measured, the system will prompt for further analysis for that particular species. If extra sampling of the fish is required,  it is labeled with a printed sticker for the species with a unique barcode that can be scanned to retrieve its record in the database.

tag for the organisms to designate its ID and what is to be done with it

Tag for the organisms to designate its ID and what is to be done with it

I thought I’d share some photos with you of some of the unique things we have seen so far fishing today. We are off the coast of Carolina and finishing up our Southern stations today into early morning!

Fish caught off of North Carolina

Fish caught off of North Carolina

Catch of the day! Thanks for reading!

Shark caught off of Carolina coast

Atlantic Sharpnose Shark caught off of Carolina coast

Kaitlin Baird: Let the Fishing Begin! September 8, 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 North East Fisheries  Science Center
Geographical Area: Atlantic Ocean steaming to south New Jersey coast
Date: September 8th
.

Location Data:
Latitude: 38° 44.58’   N
Longitude: 73 ° 39.30’  W       

Weather Data:
Air Temperature: 23.2°C (approx. 74°F)
Wind Speed: 5.05 kts
Wind Direction: from N
Surface Water Temperature: 25.29 °C (approx. 78°F)
Weather conditions: Sunny and fair

Science and Technology Log
Other than testing out the FSCS today and learning the ropes, I also learned about another type of tow we are doing on this cruise. When looking at fish stock assessment it is also important to look at the base of the food chain, you guessed it, plankton. Today we were specifically targeting zooplankton, microscopic animal drifters in the ocean that are an important food source for many of the fish and other invertebrates that we are surveying.

When I saw the nets go in, they looked a bit different than those on the R/V HSBC Atlantic Explorer, and I learned a new term, BONGO net. This is the tandem net which we are using  to tow for zooplankton at set locations while we are en route. Unlike the trawl net we tow these on the side of the ship verses the back so there is no interference by the wake made by the ship as it moves through the water. If you imagine a giant windsock with a plastic catchment at the end, this is what these nets look like. The pressure of the water moving through the net forces anything heavy to the “cod end” of the net and sieves the water out of the mesh that makes up the net.

The depth of the net tow is dependent upon bottom depth and protocol at each site, but they normally try to tow pretty close to the bottom (=/- 10 m). A separate, Conductivity, Temperature and Depth (CTD) recorder is also deployed with the nets to understand more about the ocean chemistry at set locations.  There is such a variability when towing for plankton (as it can be quite patchy) that having the two nets gives you more opportunity to capture the diversity of life that is out there. The nets are also two different mesh sizes so that they can catch zooplankton in different size classes.

Bongo Nets

Bongo Nets being deployed to 60 feet

Personal Log
It was great to get fishing today off of the coast of Maryland. We were all ready to sort anything that came down the conveyer belt. The species get sorted and then brought to the FSCS stations. Here they are measured along with anything else that needs to be done to them. I helped to get otoliths prepared and input data on gut contents, condition and sex.
Kaitlin in the wetlab with left eye and right eye flounder

Kaitlin in the wetlab with left eye and right eye flounder

One of the things I noticed were a lot of flounders, both left eye and right eye. That’s right folks, flounder usually start with one eye on each side of their heads and then eventually (species dependent) it migrates as they mature so that they sit on the bottom with both eyes on top of their heads. Depending on which way they migrate they are designated as “left eye” or “right eye” as you can see in the photos below. Did you know? These eyes can move independently of each other, pretty cool stuff!
Right Eye Flounder (Top) Left Eye Flounder (bottom)

Right Eye Flounder (Top) Witch Flounder
Left Eye Flounder (bottom) Four spot Flounder

Stay tuned for more critters! Here is just a shortlist of some that we saw today!

Rosette Skate
Little Skate
Tilefish
Goosefish
Chain dogfish
Fawn cusk-eel
Gulf stream flounder
Four spot flounder
Silver hake
Armored sea robin
LOTS of Squid

Bye for now!

Natalie Macke, August 28, 2010

NOAA Teacher at Sea: Natalie Macke
NOAA Ship: Oscar Dyson

Mission:  BASIS Survey
Geographical area of cruise: Bering Sea
Date: 8/28/2010
It’s Fish Feeding Time…
Weather Data from the Bridge :
Visibility :  <0.5 nautical miles  (Wondering what a nautical mile is??)
Wind Direction: From the W at 20 knots
Sea wave height: 2-3ft
Swell waves: WSW, 4ft
Sea temp:9.1 oC
Sea level pressure: 1013.0 mb
Air temp: 9.7 oC
Science and Technology Log:

Euphausiid Specimens (zooplankton)

We’re up to station #40 now and everyone certainly has their routine down.  One type of sampling I have yet to cover is the microscopic life; the base of the food web.  A look at the marine fisheries food web quickly reveals that in order to support the commercial fisheries as well as the vast number of marine mammals and ocean birds, there must be an abundance of phytoplankton and zooplankton available in the Bering Sea.  Evidence of this food chain is demonstrated by dissecting the stomach of a salmon.  The sample (in the picture below) revealed that the salmon had recently dined on euphaussids (commonly known as krill).   Before getting into how the zooplankton samples are collected, first let me go back and touch on the base of the food web; phytoplankton.  These samples are collected from the Niskin bottles on the CTD each cast.  The samples are preserved with formalin and will be brought back to the lab for further analysis.  Now, back to the critters..

Dissecting a salmon stomach

At every sampling station on the side deck and immediately after each CTD cast, zooplankton net tows are completed.  There are three different tows being used for the BASIS survey. The first two are vertical tows where nets that are weighted are dropped to the seafloor and then brought back to the surface thus sampling a vertical water column. The pairovet, named from the fact that is was designed as a “pair of vertical egg tows” (designed to collect pelagic egg samples) has a netting mesh size of 150 microns.  The net is simply deployed with a weight on the bottom.  When it reaches the deepest part of the water column it is brought back to the surface collecting its’ sample.  Another similar net with a 168 micron mesh size is named the Juday.  Once either of these nets is brought to the deck, it is washed down and anything caught is captured in the cod end (the name for the PVC bucket at the bottom of the net).

Cod end for Bongo

Deploying the Bongo nets off the starboard side

The last type of tow that is completed for the BASIS survey uses the Bongo nets.  This tow is considered an oblique tow since the nets essentially are lowered to about 5m from the ocean bottom and towed for a certain length of time.  If you remember from the acoustics, in daylight hours the zooplankton migrate to the ocean bottom to hide from their prey.  Since our sampling is done in daylight hours, the deep sampling depth is where we expect to find the highest density of zooplankton sample.  The mesh sizes on the two nets of the Bongo are 335 and 505 microns.  This allows for sampling of zooplankton of different sizes.   The samples are collected on board and then taken back to the lab for analysis.  They are separated by species, counted and weighed.  Biomass and species composition is determined for each sample.  The majority of the zooplankton we have seen this cruise have been euphaussids and copepods of varying types.

Oh where, oh where does the Internet go??

So as August winds down and the school year gears up, my connection to the Internet is becoming more and more important.  Since my Oceanography class is with the Virtual High School, I have to essentially set up my virtual classroom in these upcoming days.  I’ll assume my esteemed colleagues will assist me in unpacking lab equipment back at home at my physical classroom. (Even though I know.. all my orders will mysteriously wind up in other labs, I’m assured they’ll be safely placed away.)

So I tracked down Vince Welton, our Electronic’s Technician for some help understanding why sometimes I can surf, and why sometimes I can’t….

Simple…

Our Internet connection is via the geostationary satellite GE 23 at 172 degrees East. This satellite transmits over most of the Pacific Ocean (see a coverage map).  Since this satellite is positioned on the equator, that means our receiver must look essentially due south for a signal.  When our ship is northbound, the mast and stack of the Oscar Dyson simply gets in the way.  Therefore… no Internet on northbound travels.

The Oscar Dyson also has access to two Iridium satellites for communication as well as the GE 23.   These are the SAT-B which can transmit both data and voice communications and the VSAT which only allows voice transmission.  The ship can access this set of orbiting satellites when the GE 23 is unavailable due to course of travel or weather conditions.

  Personal Log
Jeanette videotaping

Jeanette videotaping

Yesterday, I got permission to stay on the trawl deck during one of our station trawls.  It was fun to be outside down with the net.  Jeanette helped do some taping which I hope to(during a few Internet-less days ahead) compile to a video for my classes.  Of course as fate would have it, our catch for the day (shown below) was not one for the record books or even worth remembering at all..  I guess that’s what the editing process is for hmmm…

Today’s catch

In the Oceanography lab, we have started our primary productivity experiments and chlorophyll analysis so learning these new procedures has been interesting and given me lots of ideas for some research topics for Edelberg’s class.  All in all, I am enjoying watching, learning and doing science here in eastern Bering Sea.  One week left..