Kevin Sullivan: Bering Sea Bloom, August 28 – September 2, 2011

NOAA Teacher at Sea
Kevin C. Sullivan
Aboard NOAA Ship Oscar Dyson
August 17 — September 2, 2011

Mission: Bering-Aleutian Salmon International Survey (BASIS)
Geographical Area:  Bering Sea
Date:  August 28 – September 2, 2011

Weather Data from the Bridge
Latitude:  56.95N
Longitude: 162.93 W
Wind Speed:  10 Knots
Surface Water Temperature: 10.5 C
Air Temperature:  55F
Relative Humidity: 97%

Science and Technology Log:

Well, at this time tomorrow, the Oscar Dyson will be tied up in port at Dutch Harbor.  This is our end destination for Leg I of the BASIS survey.  I will write-up a summary/conclusion either at that time or shortly after getting back into town.  For now, I will fill you in on some material that I promised.  As noted in earlier blogs…I have been intentionally writing in a trophic bottom up approach.  That is, I started my first blog entries with descriptions of the primary producers, the Phytoplankton.  I covered this extensively and correlated it to the oceanographic work that has been going on aboard this ship.  It seemed logical to work from the base of the food chain and work my way up the trophic levels to the more complex consumers.

However, before I close the chapter on Phytoplankton take a look at the picture I took below.  When I stepped outside and saw this, I thought I had been transported to the Caribbean.  Clear skies, calm seas, tropical blue waters are not typical descriptions for the Bering Sea.  If you look closely enough, you can even see the shadow of the clouds on the surface of the sea.   Science is the field of making observations, forming hypothesis, designing and conducting experiments and drawing conclusions about the natural world we live in.  So…what would you make of this observation?  What has caused this temporary “mirage” of tropics?  Clearly something is going on here.

Coccolithophores

Coccolithophores 08-28-11

Well, although not 100% certain, the most likely explanation is what would be called a Coccolithophore bloom.  These are single-celled algae which are characterised by special calcium carbonate plates as seen in photo below under magnification.

Coccolithophore

Coccolithophore

Under certain conditions, (some speculate that wind pattern changes fail to mix the water column favoring cocolithophore blooms as opposed to other plankton) coccolithophores can create large blooms turning the water brilliant shades of blue pending on the species of coccolithophore blooming at the time.  Ed (Chief Scientist) was telling me of a major bloom that had occurred back in the late 90’s.  I researched it a bit and the following picture is of this bloom in the same general vicinity where we are now.  Amazing to think of how microscopic plants can influence a region on the scale of an entire sea and be seen from space. *Note: this is not a false colored Image

Coccolithophore Bloom 98 Bering Sea

Coccolithophore Bloom 98 Bering Sea

There is also some speculation that these types of blooms may be linked to sub-average runs of salmon (and even impact seabirds negatively in the area).  Some hypothesize that this may be due to the idea that salmon prey heavily upon euphausiids (see picture I took below on 08-28-11 and the one centered beneath for a closer look taken from NOAA) and the euphausiids have difficulty subsiding on the extremely small coccolithophores.  Remember what I was saying about visualizing the flow of energy as a pyramid and the effects of taking out a few or many blocks that make up the base of the food chain.

euphausiids 08-28-11

euphausiids 08-28-11

Euphasiid

Euphasiid

Ok, to make this easier for the reader, I am going to stop this blog here and start a new one dedicated to the zooplankton…..I got a little sidetracked with the whole coccolithophore bloom event…….

Personal Log

Earlier this morning we were greeted with some higher winds and consequently some larger seas.  As my friend back East says conditions got “Sporty.”  Here is a picture from where we launch the CTD.  Winds were out of the SW gusting to 30 knots and seas were in the 10′ range with some larger swells thrown into the mix to keep things interesting.

Bering 09-01-11

Bering 09-01-11

Natalie Macke, September 2, 2010

NOAA Teacher at Sea: Natalie Macke
NOAA Ship: Oscar Dyson
Mission:  BASIS Survey
Geographical area of cruise: Bering Sea
Date: 9/2/2010

 

Salmon Vampires and Birds…..     
Weather Data from the Bridge :
Visibility :  10+ nautical miles (Wondering what a nautical mile is??)
Wind Direction: From the SE at 12 knots
Sea wave height: 2-3ft
Swell wave direction: 3-4 ft NW
Sea temp:9.9 oC    Sea level
pressure: 1014.4 mb    Air temp:  11.2oC
Science and Technology Log: 
NOAA Fish Biologist Brian Beckman collect blood samples from salmon

NOAA Fish Biologist Brian Beckman collect blood samples from salmon

NOAA Fish Biologist Brian Beckman is our resident salmon vampire aboard the Oscar Dyson. He’s been diligently collecting salmon blood samples anytime we catch them.  So I finally got a chance near the end of our journey to sit down and talk with Brian about why he want all those samples…

Insulin-like Growth Factor One (IGF1)
This is a ubiquitous protein that is made in the liver which causes calls to divide and grow.  So simply put, it causes growth.  Since the level of IGF1 in the blood is relatively stable, scientists can infer the growth rate of a fish by analyzing for this protein in the blood samples.  The growth rate is not an absolute value, but instead a relative comparison between fish populations.  Brian has been studying IGF1 levels in salmon off the coast of Oregon and is now trying to extrapolate or compare his findings with the salmon in the Bering Sea.  When averaging his finding over the region of coastal Oregon, he has been successful in correlating IGF1 levels in salmon with overall zooplankton abundance in the region.

More food –> healthier juvenile salmon –> higher levels of IGF1 –> greater abundance of adult salmon
Getting a Bit more technical..

IGF1

After the blood samples are collected, Brian first centrifuges them to separate out the plasma.  The IGF1 is contained in the plasma portion of the blood.  (Remember that blood is considered a heterogeneous mixture so the components can be separated by physical means)  The plasma is removed and frozen for analysis.  An immune assay is then completed on the samples back in the lab.

Brian also is concerned about the age of his salmon specimens.  Since bigger fish will be producing a steroid that stimulates the production of IGF1.  Therefore, bigger fish’s IGF1 levels are a consequence of both the effect of the steroid and the fish’s diet.  So, by collecting juvenile fish (no steroid production yet) a direct comparison can be made between the fish’s diet and it’s growth rate.

Birding on the Oscar Dyson

So on Thursday it was apparent to the crew and scientists that our fishing was done.  Troubles with the winch made balancing an open net in the water impossible.  Since our perfect 20 days of weather had us ahead of schedule, our sampling stations for this leg of the BASIS cruise were completed and our job was now done.  The scientists could now rest a bit and enjoy their cruise back to Dutch Harbor.  Except for two….. our colleagues from the Alaska Fish and Wildlife Service.  Tamara Zeller and Aaron Lang are aboard this cruise, not for fish or oceanographic samples; but instead they are here to perform an opportunistic survey about seabirds.  Armed only with a computer, binoculars and their savvy for visual details they collect data only when the ship is cruising so this last sprint to the harbor meant it was time for them to do some birding.

Tamara, Bruce, Aaron and Jeanette (left to right)

The computer pings and Tamara records what she sees from her window on the front starboard side of the bridge.  Indicators of ocean health, the Fish and Wildlife Service collects baseline data on seabird distribution and abundance in the Bering Sea.  Since most seabirds only come to land to breed, when ships like the Oscar Dyson has room aboard, a bird observer will take advantage of the opportunity to collect some data.

When I asked Aaron and Tamara what the most exciting bird this trip was, they had a hard time deciding between the two shown below.

Curlew There’s only about 5,000 left in the world

Horned Lark, Russian breeding flava subspecies Land bird from Russia

Personal Log

The ending to our cruise on the Oscar Dyson will be bitter sweet.  While I’m happy to be on land again, I will certainly miss the camaraderie of all aboard the ship.  I could not have wished for a better group of people and a more professional crew.  Everyone went to extraordinary measures to help me understand all they do AND how they do it.

Sorting Fish

Sorting Fish  

A special thanks to Ed Farley, our Chief Scientist and Jeanette Gann, my bunkmate and friend these past twenty days..   I wonder how many morning I’ll awake dreaming about collecting water samples from Niskin bottles??
Everyone on board and the NOAA crew was amazingly helpful and patient with the paparazzi teacher.  I’ll miss you all and thank you all once again…
Over and out..

Natalie Macke, August 20, 2010

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

Mission: BASIS Survey
Geographical area of cruise: Bering Sea
Date: 8/20/2010

Ed Farley, Chief Scientist

Learning from Guts and Gonads …   

Weather Data from the Bridge :
Visibility:  10 nautical miles(Wondering what a nautical mile is??)
Wind Direction: From the SE at 7 knots
Sea wave height: 1-2ft
Swell wave direction: 3 ft from the SW
Sea temp: 7.5 oC
Sea level pressure: 1026.0 mb
Air temp:  10oC
Science and Technology Log:

One of the objectives of the scientists on the BASIS cruise is to support Alaskan fisheries’ efforts to better understand the life histories of the local salmon populations.  The goal is to determine an index to better forecast the juvenile salmon’s return to western Alaska.  Thus management decisions may be made with a better understanding of long-term as well as short-term implications.  So to understand the science behind this, this chemistry teacher from the northeast had to first learn a bit about salmon….

The SockeyeKing and Coho seem to be the favorite for eating.  While the Chum is often used in dog food (thus the name Dog Salmon) and the Pink Salmon is often used for canned products.  Salmon are considered a keystone species of the region; therefore, its’ removal would have a deleterious impact to many levels of the ecosystem.  (Learn more about the Keystone Hypothesis)

Top fish are a juvenile Chum and juvenile Red Bottom is an immature Chum

Salmon are anadromous fish.  This simply means, while they spend most of their lives at sea in marine waters, they can and will return to fresh waters of lakes, streams and rivers to spawn.  The most tenuous part (in terms of environmental and human impact to the general population) of a salmon’s life seems to be in its’ juvenile stage (1st year in the ocean).  Environmental conditions, availability of food and loss to bycatch by fisheries all have impacted the salmon populations as a whole.  Our short term mission here on the Oscar Dyson is to collect data from the salmon caught during our trawls.  Below is a bit more about the specific data the scientists hope to collect and the issues behind the science of that data.

Remember that the scientists hope to establish an index to forecast the juvenile salmon’s return to western Alaska’s spawning grounds.  This index is based on relative abundance and a fitness index.  So what is a fitness index for a fish??  (I asked too..)  It’s simply the caloric content of the fish.

Making a chemistry teacher happy with yet another example of the usefulness of calorimetry.   Yes, folk..  they burn the fish and measure how much energy is released, just like we do in class except not with a soda can.  The fish are frozen for this analysis and brought back to the lab for bomb calorimetry analysis.

Various ecosystem indicators (Sea surface temperature, water column stability, types of of zooplankton, species composition and biomass) all affect both the fitness and abundance of the salmon.  Therefore, these are the data that scientists on board the Dyson are collecting.  Fish are sorted, separated, measured and then some are gutted.  Scale samples from the immature salmon are collected  for determination of age and growth history.  The scales have rings very much like the rings of a tree that can tell us not only how old a salmon is; but also, the general conditions of each growing season.  A band of small width would indicate a poorer/unhealthy condition for the fish.  Scientists have been collecting these scale samples for over fifty years and have started to compare the growth history of the salmon with climate cycles looking for overall correlations in order to predict how future climate change will impact these species.  (Want to learn more about using salmon scales for growth determination, read this article from Alaska Fish and Wildlife News)

The growth of a salmon depends much on its’ diet.  Scientists have observed a shift in the diet of the salmon when there is a shift in zooplankton populations.  During warmer years a more stable water column develops with a pronounced thermocline.  [Really warm (about 10 degrees Celsius or so) on top and really cold on bottom (close to 0 degrees Celsius)]  Associated with this type of water column are the presence of zooplankton with a smaller lipid content (less fat).  As a result, the salmon (specifically the Sockeye) were observed to be eating pollock during warmer years.  Normally, the majority of the salmon diet is zooplankton.  During colder years, a less stable water column develops and zooplankton with a higher fat content were observed to be the main diet of the juveniles.  This link between the salmon and pollock populations causes an uncertainty in forecasting future salmon population changes.   The impact of the pollock fisheries has been mostly documented in the past simply in terms of bycatch.  Summer pollock fishing often results in bycatch of Chums; whereas the winter pollock season impacts the Chinook.  Understanding this newer biological relationship between salmon and pollock is important to predicting how changes in pollock populations will ultimately impact the future of salmon.  This future causes great concern among the local northern native groupswho rely on the Chinook’s population as a major food source.

Personal Log:
We were treated Thursday evening with some blue sky and then on Friday morning to a beautiful sunrise with a view of the mountains of Unimak Island.  When grey is a common daily theme any color is appreciated oh so more..

MORNING VIEW

EVENING SKY

Natalie Macke, August 18, 2010

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

Mission:  BASIS Survey
Geographical area of cruise: Bering Sea
Date: 8/18/2010
 
“Learning a Different Sort of Job…”

A King Salmon catch

                                             

Weather Data from the Bridge :
Visibility :  5 nautical miles (Wondering what a nautical mile is??)
Wind Direction: From the WSW at 16 knots
Sea wave height: 3ft
Swell wave direction: 5 ft from the WSW
Sea temp: 9.4oC
Sea level pressure: 1026.0 mb
Air temp:  8.8oC
 Science and Technology Log:
CTD

CTD

It seems my background in chemical oceanography is coming into some use this cruise.  Since one of the scientists was not able to make the journey, the oceanography lab was short-handed.  So, I immediately was put to work to help collect and process the oceanography samples.  Below is a bit more about what that entails.

Scientists use an instrument referred to simply as a CTD (acronym for conductivity, temperature and depth) to electronically collect much of the physical ocean data.  Shown to the right, the CTD is a rosette with numerous electronic sensors and water collection bottles (known as Niskin bottles) that is slowly lowered into the ocean.  A cable electronically transmits data from the apparatus back up in real-time to the computer screen monitored by the scientists.  Viewing the data, an immediate decision can be made as to where (at what depth) a water sample should be retrieved for further analysis.

Jeanette looking at the CTD data

Jeanette, the oceanographer on board, is viewing the screen with her log book.  She’ll look at the pycnocline and fluorescence data to decide where she’ll “fire the Niskin bottles”.  This simply means to send an electronic signal down to trigger the closing of the tube and thus capturing a water sample at that specific depth.  The general plan is to capture samples from 5m above the seafloor, two samples on the bottom and then top of the pycnocline.  Two additional samples will be also taken at the fluorescence maximum as well as near the surface.

The fluorescence maximum is where the fluorometer has identified the greatest biomass of phytoplankton in the water column.

Jeanette and I are pondering our catch of the day, “Oceanographer’s style”

Once the CTD has been recovered back onboard, we take samples from the Niskin bottles for further study…  So what will we do with our samples??
–  Sample for nutrients such as nitrates and nitrites (food for the phytoplankton)
–  Sample for Oxygen-18 isotopes
–  Sample for different sizes of phytoplankton by filtering various aliquots using filter paper with different pore sizes.

Niskin bottle sampling

Filtering water samples

Once the samples are recovered from the Niskin bottles, (Each sample is given number associated with the depth from which it was collected) the samples are taken back to the oceanography lab for processing.  Samples are filtered for a given size of phytoplankton.  These sizes range from greater than 10 micrometers all the way down to GFF (greater than fine fraction)  meaning anything smaller will be bacteria and viruses.    The filter papers are recovered from the processing and will be brought back to shore for plankton analysis.  Ultimately, this data will help confirm the analysis completed electronically by the fluorometer on the CTD.  Our lab on the Oscar Dyson is quite nice and as long as seas remain calm as they have been, I have to say that my new job is one that I feel quite comfortable with…

Oceanography Wet Lab

Oceanography Wet Lab
 Personal Log:

I have to say that I have gotten accustomed to the layout of the Oscar Dyson quite quickly and easily.  The levels are numbered with the Bridge being Level #1.  My berth is on Level #4 and the Oceanography Lab and the Mess hall are both on Level #3.  That’s pretty much all that I really have to know..   Since seas have been calm, the gentle rocking has simply acted as a sedative to make you want to eat Oreo cookies and then take a nap.  I think I better locate the two gyms on board in the near future..  I have very much enjoyed getting to know the crew and scientists on board and look forward to learning much more from all of them.  Even drills are a bit different on the Dyson…

My very own “Gumby Suit”