Mark Van Arsdale: What Makes Up an Ecosystem? Part II – Phytoplankton, September 14, 2018

NOAA Teacher at Sea

Mark Van Arsdale

Aboard R/V Tiglax

September 11 – 26, 2018


Mission: Long Term Ecological Monitoring

Geographic Area of Cruise: North Gulf of Alaska

Date: September 14, 2018


Weather Data from the Bridge

Mostly cloudy, winds variable 10 knots, waves to four feet

58.27 N, 148.07 W (Gulf of Alaska Line)


Science Log

What Makes Up an Ecosystem?  Part II Phytoplankton

Most of my students know that the sun provides the foundational energy for almost all of Earth’s food webs.  Yet many students will get stumped when I ask them, where does the mass of a tree comes from?  The answer of course is carbon dioxide from the air, but I bet you already knew that.

Scientists use the term “primary productivity” to explain how trees, plants, and algae take in carbon dioxide and “fix it” into carbohydrates during the process of photosynthesis.  Out here in the Gulf of Alaska, the primary producers are phytoplankton (primarily diatoms and dinoflagellates). When examining diatoms under a microscope, they look like tiny golden pillboxes, or perhaps Oreos if you are feeling hungry.

Primary productivity experiments running on the back deck of the Tiglax.

Primary productivity experiments running on the back deck of the Tiglax.

One of the teams of scientists on board is trying to measure the rates of primary productivity using captive phytoplankton and a homemade incubation chamber. They collect phytoplankton samples, store them in sealed containers, and then place them into the incubator.  Within their sample jars, they inject a C13 isotope.  After the experiment has run its course, they will use vacuum filtration to separate the phytoplankton cells from the seawater.  Once the phytoplankton cells are captured on filter paper they can measure the ratios of C12 to C13. Almost all of the carbon available in the environment is C12 and can be distinguished from C13.  The ratios of C12 to C13 in the cells gives them a measurement of how much dissolved carbon is being “fixed” into sugars by phytoplankton.  Apparently using C14  would actually work better but C14 is radioactive and the Tiglax is not equipped with the facilities to hand using a radioactive substance.

During the September survey, phytoplankton numbers are much lower than they are in the spring.  The nutrients that they need to grow have largely been used up.  Winter storms will mix the water and bring large amounts of nutrients back to the surface.  When sunlight returns in April, all of the conditions necessary for phytoplankton growth will be present, and the North Gulf of Alaska will experience a phytoplankton bloom.  It’s these phytoplankton blooms that create the foundation for the entire Gulf of Alaska ecosystem.

Personal Log

Interesting things to see

The night shift is not getting any easier.  The cumulative effects of too little sleep are starting to catch up to me, and last night I found myself dosing off between plankton tows.  The tows were more interesting though.  Once we got past the edge of the continental shelf, the diversity of zooplankton species increased and we started to see lantern fish in each of the tows.  Lantern fish spend their days below one thousand feet in the darkness of the mesopelagic and then migrate up each night to feed on zooplankton.  The have a line of photophores (light producing cells) on their ventral sides.  When they light them up, their bodies blend in to the faint light above, hiding their silhouette, making them functionally invisible.

A lantern fish with its bioluminescent photophores visible along its belly.

A lantern fish with its bioluminescent photophores visible along its belly.

Once I am up in the morning, the most fun place to hang out on the Tiglax is the flying bridge.  Almost fifty feet up and sitting on top of the wheelhouse, it has a cushioned bench, a wind block, and a killer view.  This is where our bird and marine mammal observers work.  Normally there is one U.S. Fish and Wildlife observer who works while the boat is transiting from one station to the next.  On this trip, there is a second observer in training.  The observers’ job is to use a very specific protocol to count and identify any sea bird or marine mammal seen along the transect lines.

Today we saw lots of albatross; mostly black-footed, but a few Laysan, and one short-tailed albatross that landed next to the boat while were casting the CTD.  The short-tailed albatross was nearly extinct a few years ago, and today is still considered endangered. That bird was one of only 4000 of its species remaining.  Albatross have an unfortunate tendency to follow long-line fishing boats.  They try to grab the bait off of hooks and often are drowned as the hooks drag them to the bottom.  Albatross are a wonder to watch as they glide effortlessly a few inches above the waves.  They have narrow tapered wings that are comically long. When they land on the water, they fold their gangly wings back in a way that reminds me of a kid whose growth spurts hit long before their body knows what to do with all of that height.   While flying, however, they are a picture of grace and efficiency.  They glide effortlessly just a few inches above the water, scanning for an unsuspecting fish or squid.  When some species of albatross fledge from their nesting grounds, they may not set foot on land again for seven years, when their own reproductive instincts drive them to land to look for a mate.

Our birders seem to appreciate anyone who shares their enthusiasm for birds and are very patient with all of my “What species is that?” questions.  They have been seeing whales as well.  Fin and sperm whales are common in this part of the gulf and they have seen both.

A Laysan Albatross

A Laysan Albatross, photo credit Dan Cushing


Did You Know?

Albatross, along with many other sea birds, have life spans comparable to humans.  It’s not uncommon for them to live sixty or seventy years, and they don’t reach reproductive maturity until well into their teens.


Animals Seen Today

  • Fin and sperm whales
  • Storm Petrels, tufted puffins, Laysan and black-footed and short-tailed albatross, flesh footed shearwater


Kevin Sullivan: Bering Sea Bound, August 22, 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 22-24, 2011

Weather Data from the Bridge
Latitude:  N
Longitude:  W
Wind Speed:  20-23kts Tue,Wed. seas 9′ Thu 8/25 = calm
Surface Water Temperature:  C
Air Temperature:  55F
Relative Humidity: 70%

Science and Technology Log

We are on Day II of our travels to get to our first sampling station located in the SE Bering Sea.  We will begin our fishing operations today!  We have had decent weather thus far although we did just go through Unimak Pass (see picture below of location) which is a narrow strait between the Bering Sea and the North Pacific Ocean.  This passage offered a time of heavier seas.  I’m guessing that like any strait, the currents may become more funneled and the seas “confused” as they squeeze through this area.  It’s kind of analogous to it being more windy in between buildings of a major city vs. suburbia as the wind is funneled between skyscrapers.  I also imagine this to be a popular crossing for marine mammals as well.

Interesting to think that both marine mammals and humans use this passage to both get to the same things: a food source and a travel route.  It’s a migratory “highway” for marine mammals, and a heavily-trafficked area for humans in international trade and commercial fisheries.

Anyway, the Bering Sea is a very unique body of water. It really is the way that I imagined it.  It is as though you are looking through a kaleidoscope and the only offerings are 1000 different shades of grey.  It is rainy, foggy, and windy.  I can appreciate how this sea has been the graveyard for so many souls and fishing vessels in the past who have tried to extract the bounties it has to offer.

unimak pass

unimak pass

As of Wednesday, the 24th, we have finished 4 stations of the 30 that have been planned for Leg I of this study (Leg II is of similar duration and goals).  I was involved with helping the oceanographic crew with their tasks of collecting and evaluating various parameters of water chemistry.  To do this, an instrument called a “CTD”– an acronym for Conductivity, Temperature, and Depth — is lowered.  This instrument is the primary tool for determining these essential physical properties of sea water.  It allows the scientists to record detailed charting of these various parameters throughout the water column and helps us to understand how the ocean affects life and vice-versa.

One aspect that I found very interesting is the analyzing of chlorophyll through the water column.  All plant life on Earth contains the photosynthetic pigment called chlorophyll.  Phytoplankton (planktonic plants) occupy the photic zone of all water bodies.  Knowing that we live on a blue planet dominated by 70% coverage in water, we can thank these phytoplankton for their byproduct in photosynthesis, which is oxygen.  Kind of strange how you often symbolize the environmental movement with cutting down of the rainforests and cries that we are eliminating the trees that give us the air we breath.  This is true, but proportionately speaking, with an ocean-dominated sphere, we can thank these phytoplankton and photosynthetic bacteria for a large percentage of our oxygen.  Additionally, being at the base of the food chain and primary consumers, these extraordinary plants have carved a name for themselves in any marine investigation/study.

The procedure to measure chlorophyll involves the following:  water from the Niskin Bottles (attached to the CTD, used to “capture” water at select depths) is filtered through different filter meshes and the samples are deep-frozen at -80F.  To analyze chlorophyll content, the frozen sample filter is immersed in a 90% solution of DI (Distilled Water) and acetone which liberates the chlorophyll from the phytoplankton.  This is then sent through a fluorometer.

Filtering water from CTD for Chlorophyll Measurements

Filtering water from CTD for Chlorophyll Measurements

Fluorescence is the phenomena of some compounds to absorb specific wavelengths of light and then, emit longer wavelengths of light.  Chlorophyll absorbs blue light and emits, or fluoresces, red light and can be detected by this fluorometer.

Fluorometer; Berring Sea 08-25-11

Fluorometer; Berring Sea 08-25-11

Amazing to think that with this microscopic plant life, you can extrapolate out and potentially draw some general conclusions about the overall health of a place as large as the Bering Sea. Oceanographic work is remarkable.

CTD Berring Sea 08-24-11

CTD Berring Sea 08-24-11


Personal Log

The crew aboard the Oscar Dyson have been very accommodating and more than willing to educate me and take the time to physically show me how these scientific investigations work.  I am very impressed with the level of professionalism.  As a teacher, I know that most often, the best way to teach students is to present the material in a hands-on fashion…inquiry/discovery based.   This is clearly the format that I have been involved in while in the Bering Sea and I am learning a tremendous amount of information.

The food has been excellent (much better than I am used to while out at sea).  The seas have been a bit on the rough side but seem to be settling down somewhat (although, I do see a few Low Pressure Systems lined up, ready to enter the Bering Sea…..tis the season).  Veteran seamen in this area and even in the Mid-Atlantic off of NJ, know that this is the time of year when the weather starts to change). On a side note, I see that Hurricane Irene has its eyes set on the Eastern Seaboard.  I am hoping that everyone will take caution in my home state of NJ.

Lastly, it’s amazing also to think of the depth and extent of NOAA.  With oceans covering 70% of our planet and the entire planet encompassed by a small envelope of atmosphere that we breathe, it is fair to say that the National Oceanic and Atmospheric Administration is a part of our everyday lives.  I am in the Bering Sea, one of the most remote and harsh places this planet has to offer and across the country, there are “Hurricane Hunters” flying into the eye of a hurricane that could potentially impact millions of people along the Mid Atlantic………..Both operated and run by NOAA!

Sunset on the Berring Sea 08-24-11

Sunset on the Bering Sea 08-24-11