Cara Nelson: Little Creatures that Rule the World, September 23, 2019

NOAA Teacher at Sea

Cara Nelson

Aboard USFWS R/V Tiglax

September 11-25, 2019


Mission: Northern Gulf of Alaska Long-Term Ecological Research project

Geographic Area of Cruise: Northern Gulf of Alaska – currently sheltering in Kodiak harbor again

Date: September 23, 2019

Weather Data from the Bridge:

Time: 13:30
Latitude: 57º47.214’ N
Longitude: 152º24.150’ E
Wind: Northwest 8 knots
Air Temperature: 11ºC (51ºF)
Air Pressure: 993 millibars
Overcast, light rain


Science and Technology Log

As we near the end of our trip, I want to focus on a topic that it is the heart of the LTER study: zooplankton.  Zooplankton are probably the most underappreciated part of the ocean, always taking second stage to the conspicuous vertebrates that capture people’s attention.  I would argue however, that these animals deserve our highest recognition. These small ocean drifters many of which take part in the world’s largest animal migration each day. This migration is a vertical migration from the ocean depths, where they spend their days in the darkness avoiding predators, to the surface at night, where they feed on phytoplankton (plant plankton). Among the zooplankton, the humble copepod, the “oar-footed,” “insect of the sea,” makes up 80% of the animal mass in the water column.  These copepods act as a conduit of energy in the food chain, from primary producers all the way up to the seabirds and marine mammals.

copepod
A copepod. Photo credit: Russ Hopcroft.

Aboard the R/V Tiglax, zooplankton and copepods are collected in a variety of manners.  During the day, a CalVet plankton net is used to collect plankton in the top 100 meters of the water column.  

CalVet
Russ prepares the CalVet for deployment.

On the night shift, we alternated between a Bongo net and a Multinet depending on our sampling location.  The Bongo net is lowered to 200 meters of depth (or 5 meters above the bottom depending on depth) and is towed back to the surface at a constant rate.  This allows us to capture the vertical migrators during the night.  How do we know where it is in the water column and its flow rate you may ask?  Each net is attached to the winch via a smart cable.  This cable communicates with the onboard computer and allows the scientists to monitor the tow in real time from the lab. 

bongo net
The Bongo net coming back aboard. Note the smart cable attached to the winch that communicates with the computer. Grabbing the Bongo can be tricky in high seas as we learned on this trip!

The Multinet is a much higher tech piece of equipment.  It contains five different nets each with a cod end.  It too is dropped to the same depth as the Bongo, however each net is fired open and closed from the computer at specific depths to allow for a snapshot of the community at different vertical depths.

multinet
The Multinet about to be deployed during our night shift.

Copepod research is the focus of the two chief scientists, Russ Hopcroft and Jennifer Questel aboard R/V Tiglax.  Much of the research must occur back in the laboratories of the University of Alaska Fairbanks.  For example, Jenn’s research focuses on analyzing the biodiversity of copepods in the NGA at the molecular level, using DNA barcoding to identify species and assess population genetics.  A DNA barcode is analogous to a barcode you would find on merchandise like a box of cereal.  The DNA barcode can be read and this gives a species level identification of the zooplankton.  This methodology provides a better resolution of the diversity of planktonic communities because there are many cryptic species (morphologically identical) and early life stages that lack characteristics for positive identification.  Her samples collected onboard are carefully stored in ethanol and frozen for transport back to her lab.  Her winter will involve countless hours of DNA extraction, sequencing and analysis of the data.

One aspect of the LTER study that Russ is exploring is how successful certain copepod species are at finding and storing food.  Neocalanus copepods, a dominate species in our collections, are arthropods that have a life cycle similar to insects.  They have two major life forms, they start as a nauplius, or larval stage, and then metamorphisize into the copepodite form, in which they take on the more familiar arthropod appearance as they transition to adulthood.  Neocalanus then spends the spring and summer in the NGA feasting on the rich phytoplankton blooms. They accumulate fat stores, similar to our Alaska grizzlies.   In June, these lipid-rich animals will settle down into the deep dark depths of the ocean, presumably where there is less turbulence and predation.  The males die shortly after mating, but the females will overwinter in a state called diapause, similar to hibernation.  The females do not feed during this period of diapause and thus must have stock-piled enough lipids to not only survive the next six months, but also for the critical next step of egg production.  Egg production begins in December to January and after egg release, these females – like salmon – will die as the cycle begins again. 

Part of Russ’s assessment of the Neocalanus is to photograph them in the lab aboard the ship as they are collected.  The size of the lipid sac is measured relative to their body size and recorded.  If females do not store enough lipids, then the population could be dramatically altered the following season. These organisms that are live sorted on the ship will then be further studied back in the laboratory using another type of molecular analysis to look at their gene expression to understand if they are food-stressed as they come out of diapause.

Russ Hopcroft at microscope
I watch in awe as Russ is able to manipulate and photograph copepods under a microscope amid the rocking ship.
Neocalanus
Two Neocalanus with their lipid sacs visible down the center of the body. Note the difference in the size of the lipid storage between the two.

Back in the UAF laboratory, countless hours must be spent on a microscope by technicians and students analyzing the samples collected onboard.  To give an idea of the scope of this work, it takes approximately 4 hours to process one sample.  A typical cruise generates 250 samples for morphological analysis to community description, which includes abundance, biomass, life stage, gender, size and body weight information.  There are three cruises in a season, and thus the work extends well into the spring. To save time, computers are also used to analyze a subset of the samples which are then checked by a technician.  However, at this stage, the computer output does not yet meet the accuracy of a human technician. All of these approaches serve to better understand the health of the zooplankton community in the NGA. Knowing how much zooplankton there is, who is there and how fatty they are, will tell us both the quantity and quality of food available to the fish, seabirds and marine mammals that prey upon them.  Significant changes both inter-annually and long-term of zooplankton community composition and abundance could have transformative effects through the food chain.  This research provides critical baseline data as stressors, such as a changing climate, continue to impact the NGA ecosystem.


Personal Log

After sheltering in Kodiak harbor overnight Friday, we once again were able to head back out during a break in the weather.  We departed Kodiak in blue skies and brisk winds on Saturday. 

sunset
Sunset over Marmot Island at the start of the Kodiak line on what would end up being our last night of sampling.

We made it to the start of the Kodiak line by sundown and began our night of sampling with the goal of getting through six stations.  The swells left over from the last gale were quite challenging, with safety a top priority this evening.  Waves were crashing over the top rale as we worked and the boat pitched side to side.  Walking the corridor from the stern to the bow required precise timing, lest you get soaked by a breaking wave, as poor Heidi did at least three times.

Despite having to pull the Methot early on one station and skip it all together on another due to the rough seas, we had an amazingly efficient and successful evening.  Our team was amazing to work with and Dan captured one last photo of us as we wrapped up our shift at 6am.

night shift group photo
The night shift “A Team”: Emily, Jenn, Jen, Cara and Heidi.

The day crew worked fast and furious on the return to station one as once again, another gale was forecast.  This gale was the worst yet, dipping down to 956 millibars in pressure with the word STORM written across the forecast screen for the entire Gulf of Alaska.  Luckily we were able to make it back into Kodiak harbor by Sunday evening just as winds and waves began to build.  After riding out the storm overnight we are still waiting for the 4pm forecast to reassess our final days two days.  The crew grows weary of sitting idle as the precious window for sampling closes.  Stay tuned for a follow up blog as I return to solid ground on Wednesday! 


Did You Know?

Copepods are the most biologically diverse zooplankton and even outnumber the biodiversity of terrestrial insects!

Catherine Fuller: Out of the Sea and into the Lab, July 3, 2019

NOAA Teacher at Sea

Catherine Fuller

Aboard R/V Sikuliaq

June 29 – July 18, 2019


Mission: Northern Gulf of Alaska (NGA) Long-Term Ecological Research (LTER)

Geographic Area of Cruise: Northern Gulf of Alaska

Date: July 3, 2019

Weather Data from the Bridge

Latitude: 58° 54.647’ N
Longitude: 146° 00.022’ W
Wave Height: 4-5 ft.
Wind Speed: 1.9 knots
Wind Direction: roughly 90 degrees, but variable
Visibility: 1 nm
Air Temperature: 13.2 °C
Barometric Pressure: 1014.4 mb
Sky: Clear, then foggy

Weather overview

We have been fortunate so far to have very calm conditions.  Winds have been variable or light and are expected to continue to be so through the weekend at least.  Wave heights have generally been about 3 feet, although they’re up to 4-5 feet today, and are expected to drop tomorrow.  The calm weather is critical for some of the testing being done, and thus is allowing more to happen.

Science and Technology Log

The focus of all of testing on board is plankton.  As the base of the food web, all species depend on their health and abundance for survival. There are multiple teams who are focused on various aspects of plankton and their reaction to environmental conditions.  Kira Monell is a graduate student at the University of Hawaii at Manoa who is working under the direction of Dr. Russ Hopcroft while on board.  She is studying zooplankton, or the animal version of plankton.   She is specifically focusing on Neocalanus flemingeri, a type of sub-arctic copepod.  It is important to study zooplankton because they provide a link between phytoplankton (the plant version of plankton) and larger fish on the food web.  Copepods are extremely abundant and varietal, found just about everywhere in the world.  They are an important food source for most aquatic species (they exist in both salt and fresh water).  They are a trophic link – a connection in the food web.  Her target species is special because they mostly eat phytoplankton during the seasonal plankton blooms.  They convert their food into a lot of lipids (fats) and thus are great sources of food and energy for larger fish.  After fattening up, they go deep into the ocean to hibernate around mid-summer. 

Kira is specifically focused on the termination of their hibernation (technically called diapause).  She is doing genetic testing to see which genes are activated or deactivated during this phase of their lives.  Messenger ribonucleic acid (or mRNA) coded by these genes is required to construct the enzymes that cause changes in body functions, so she is looking at levels of different mRNA in the copepods. She is expecting to see an increase in genes relating to oogenesis (egg formation).  Her female copepods go into diapause ready to start making eggs, so she expects to see changes in genes relating to egg growth as they come wake up from diapause.

Kira is examining copepods through three different experiments.  With some samples, she adds a stain called EDU (a dye that labels cells that are just about to divide) into her samples and then checks them at 24 hours to see which cells have divided.  Because the copepods are still alive, she can check back to see what further cell division have happened over longer periods of time.  A fluorescent microscope is required to see the EDU.  Scientists still struggle to understand what actually triggers emergence from diapause since deep water copepods don’t experience seasonal light changes, or other potential triggers that might exist on the surface. 

Another thing she is looking at is in-situ hybridization.  She makes a tag that is very specific for the gene she wants to examine.  When the probe gene is introduced, it attaches to the gene she wants to look at only if it is being actively copied.  Kira then attaches a colored or fluorescent dye to the probe and in that way she can track which genes are being expressed in specific areas of the body.

The third project that she is working on is trancriptum analysis, which requires building a complete “catalog” that shows all the RNA used by a species. She can then look at which gene transcripts are present, and in how abundant they are, so as to compare them to the “average” version of a transcriptum to see which genes are being turned off and on under certain conditions.

To obtain samples of copepods, the zooplankton team, including Kira, uses Calvet nets.  These are four long nets that terminate in collection tubes. Weight is added to the bottom of the nets and they are submerged off the stern to 100 meters of depth and then pulled back up (a process that takes roughly five minutes).  The nets are then rinsed to collect the samples in the tubes, which are transferred into jars and brought to the lab for more detailed sorting and examination. 

Calvet rising
The Calvet is returning to the surface after being submerged
Kira and Kate rinse net
Kira and Kate rinse the length of the nets to collect their samples in the tubes in the end.

As the Calvet rises you can see the full net. (This video has no dialogue.)



Personal Log

back deck
This is the main working deck at the stern of the ship.

Getting prepared to go out on deck safely!

All of the sample collection happens on the working deck at the stern of the R/V Sikuliaq or in the adjacent Baltic Room.  The back deck is equipped with a variety of cranes and winches that are designed to handle heavy weights and lines under tension.  As such, it is critical to wear the proper protective gear when you’re out there: boots (preferably steel-toed), a hard hat and a flotation vest of coat.  If there’s a potential to get wet or dirty, rain gear or waterproof bibs are essential to stay dry and relatively clean. Being properly dressed is a process that took getting used to, but now it’s habit.  Again, we’re lucky to have had good weather, so the deck is usually warm enough to wear a t-shirt and jeans.  I find it calming to be outside, so I am enjoying learning about the sampling methods of other teams by watching and sometimes assisting them.  There are also observation decks at the bow that do not require safety gear.  A few of us have discovered that the forward decks are much quieter and are good spaces to decompress and look for sea life. 


Animals Seen in the Last 24 Hours:

We’ve seen a few species of birds including black turnstones, glaucous-winged gulls, Black-winged kittiwakes, as well as deeper water birds such as storm petrels and shearwaters.  In addition, there have been small pods of dolphins in the distance and one humpback whale (all we saw was the tail).

Katie Gavenus, Bonus Blog: MIXOTROPHS, May 5, 2019

NOAA Teacher at Sea

Katie Gavenus

Aboard R/V Tiglax

April 26 – May 9, 2019

Mission: Northern Gulf of Alaska Long-Term Ecological Research project

Geographic Area of Cruise: Northern Gulf of Alaska – currently in transit from ‘Seward Line’ to ‘Kodiak Line’

Date: May 5, 2019

Weather Data from the Bridge

Time: 2305
Latitude: 57o 34.6915’
Longitude: 150o 06.9789’
Wind: 18 knots, South
Seas: 4-6 feet
Air Temperature: 46oF (8oC)
Air pressure: 1004 millibars
Cloudy, light rain

 

Science and Technology Log

I was going to just fold the information about mixotrophs into the phytoplankton blog, but this is so interesting it deserves its own separate blog!

On land, there are plants that photosynthesize to make their own food. These are called autotrophs – self-feeding.  And there are animals that feed on other organisms for food – these are called heterotrophs – other-feeding.  In the ocean, the same is generally assumed.  Phytoplankton, algae, and sea grasses are considered autotrophs because they photosynthesize.  Zooplankton, fish, birds, marine mammals, and benthic invertebrates are considered heterotrophs because they feed on photosynthetic organisms or other heterotrophs.  They cannot make their own food.  But it turns out that the line between phytoplankton and zooplankton is blurry and porous.  It is in this nebulous area that mixotrophs take the stage!

Mixotrophs are organisms that can both photosynthesize and feed on other organisms.  There are two main strategies that lead to mixotrophy.  Some organisms, such as species of dinoflagellate called Ceratium, are inherently photosynthetic.  They have their own chloroplasts and use them to make sugars.  But, when conditions make photosynthesis less favorable or feeding more advantageous, these Ceratium will prey on ciliates and/or bacteria.  Bacteria are phosphorous, nitrogen, and iron rich so it is beneficial for Ceratium to feed on them at least occasionally. Microscopy work makes it possible to see the vacuole filled with food inside the photosynthetic Ceratium. 

illustration of mixotrophic dinoflagellate Ceratium

I created this drawing after viewing a number of microscopy photos of the mixotrophic dinoflagellate Ceratium under different lights and stains. This artistic rendition combines those different views to show the outside structure of the dinoflagellate as well as the nucleus, food vacuole and chloroplasts. (Drawing by Katie Gavenus)

Other organisms, including many ciliates, were long known to be heterotrophic.  They feed on other organisms, and it is particularly common for them to eat phytoplankton and especially cryptophyte algae. Recent research has revealed, however, that many ciliates will retain rather than digest the chloroplasts from the phytoplankton they’ve eaten and use them to photosynthesize for their own benefit. Viewing these mixotrophs under blue light with a microscope causes the retained chloroplasts to fluoresce.  I saw photos of them and they are just packed with chloroplasts!

illustration of mixotrophic ciliate Tontonia sp.

The mixotrophic ciliate Tontonia sp. eats phytoplankton but retains the chloroplasts from their food in order to photosynthesize on their own! I made this drawing based off of photos, showing both the outside structure of the Tontonia and how the chloroplasts fluoresce as red when viewed with blue light. (Drawing by Katie Gavenus)

Mixotrophs are an important part of the Gulf of Alaska ecosystem.  They may even help to explain how a modestly productive ecosystem (in terms of phytoplankton) can support highly productive upper trophic levels. Mixotrophy can increase the efficiency of energy transfer through the trophic levels, so more of the energy from primary productivity supports the growth and reproduction of upper trophic levels. They also may increase the resiliency of the ecosystem, since these organisms can adjust to variability in light, nutrients, and phytoplankton availability by focusing more on photosynthesis or more on finding prey. Yet little is known about mixotrophs.  Only about one quarter of the important mixotroph species in the Gulf of Alaska have been studied in any way, shape or form!

Researchers are trying to determine what kinds of phytoplankton the mixotrophic ciliates and dinoflagellates are retaining chloroplasts from.  They are also curious whether this varies by location, season or year.  Understanding the conditions in which mixotrophic organisms derive energy from photosynthesis and the conditions in which they choose to feed is another area of research focus, especially because it has important ramifications for carbon and nutrient cycling and productivity across trophic levels.  And it is all very fascinating!

food web illustration

A drawing illustrating a fascinating, tightly linked portion of the Gulf of Alaska food web. Mesodinium rubrum must eat cryptophyte algae (this is called obligate feeding). The Mesodinium rubrum retain the chloroplasts from the cryptophyte algae, using them to supplement their own diet through photosynthesis. In turn, Dinophysis sp. must feed on Mesodinium rubrum. And the Dinophysis retain the chloroplasts from the Mesodinium that originally were from cryptophyte algae! (Drawing by Katie Gavenus)

Did you know?

Well over half of the oxygen on earth comes from photosynthetic organisms in the ocean.  So next time you take a breath, remember to thank phytoplankton, algae, and marine plants!

Personal Log:

Tonight was likely our last full night of work, as we expect rough seas and high winds will roll in around midnight tomorrow and persist until the afternoon before we head back to Seward.  We were able to get bongo net sampling completed at 6 stations along the Kodiak Line, and hope that in the next two nights we can get 2-4 stations done before the weather closes in on us and 2-4 nets on the last evening as we head back to Seward.

Despite our push to get 6 stations finished tonight, we took time to look more closely at one of the samples we pulled up.  It contained a squid as well as a really cool parasitic amphipod called Phronima that lives inside of a gelatinous type of zooplankton called doliolids.  Check out the photos and videos below for a glimpse of these awesome creatures (I couldn’t figure out how to mute the audio, but I would recommend doing that for a less distracting video experience).

 

 

Phronima

A parasitic Phronima amphipod. This animal typically lives inside doliolids, a type of gelatinous zooplankton. Apparently its body structure and fierce claw-like appendages inspired the design of “Predator.”

 

 

 

 

Katie Gavenus: Thinking Like A Hungry Bird, April 28, 2019

NOAA Teacher at Sea

Katie Gavenus

Aboard R/V Tiglax

April 26-May 9, 2019

 

Mission: Northern Gulf of Alaska Long-Term Ecological Research project

Geographic Area of Cruise: Northern Gulf of Alaska – currently on the ‘Middleton [Island] Line’

Date: April 28, 2019

 

Weather Data from the Bridge

Time: 1715
Latitude: 59o 39.0964’ N
Longitude: 146o05.9254’ W
Wind: Southeast, 15 knots
Air Temperature: 10oC (49oF)
Air pressure: 1034 millibars
Cloudy, no precipitation

 

Science and Technology Log

Yesterday was my first full day at sea, and it was a special one! Because each station needs to be sampled both at night and during the day, coordinating the schedule in the most efficient way requires a lot of adjustments. We arrived on the Middleton Line early yesterday afternoon, but in order to best synchronize the sampling, the decision was made that we would wait until that night to begin sampling on the line. We anchored near Middleton Island and the crew of R/V Tiglax ferried some of us to shore on the zodiac (rubber skiff).

This R&R trip turned out to be incredibly interesting and relevant to the research taking place in the LTER. An old radio tower on the island has been slowly taken over by seabirds… and seabird scientists. The bird biologists from the Institute for Seabird Research and Conservation have made modifications to the tower so that they can easily observe, study, and band the black-legged kittiwakes and cormorants that choose to nest on the shelfboards they’ve augmented the tower with. We were allowed to climb up into the tower, where removable plexi-glass windows look out onto each individual pair’s nesting area. This early in the season, the black-legged kittiwakes are making claims on nesting areas but have not yet built nests. Notes written above each window identified the birds that nested there last season, and we were keen to discern that many of the pairs had returned to their spot.

Gavenus1Birds

Black-legged kittiwakes are visible through the observation windows in the nesting tower on Middleton Island.

Gavenus2Birds

Nesting tower on Middleton Island.

The lead researcher on the Institute for Seabird Research and Conservation (ISRC) project was curious about what the LTER researchers were finding along the Middleton Line stations. He explained that the birds “aren’t happy” this spring and are traveling unusually long distances and staying away for multiple days, which might indicate that these black-legged kittiwakes are having trouble finding high-quality, accessible food. In particular, he noted that he hasn’t seen any evidence they’ve been consuming the small lantern fish (myctophids) that generally are an important and consistent food source from them in the spring. These myctophids tend to live offshore from Middleton Island and migrate to the surface at night. We’ll be sampling some of that area tonight, and I am eager to see if we might catch any in the 0.5 mm mesh ‘bongo’ nets that we use to sample zooplankton at each station.

The kittiwakes feed on myctophids. The myctophids feed on various species of zooplankton. The zooplankton feed on phytoplankton, or sometimes microzooplankton that in turn feeds on phytoplankton. The phytoplankton productivity is driven by complex interactions of environmental conditions, impacted by factors such as light availability, water temperature and salinity as well as the presence of nutrients and trace metals. And these water conditions are driven by abiotic factors – such as currents, tides, weather, wind, and freshwater input from terrestrial ecosystems – as well as the biotic processes that drive the movement of carbon, nutrients, and metals through the ecosystem.

Scientists deploy CTD

This CTD instrument and water sampling rosette is deployed at each station during the day to collect information about temperature and salinity. It also collects water that is analyzed for dissolved oxygen, nitrates, chlorophyll, dissolved inorganic carbon, dissolved organic carbon, and particulates.

CTD at sunset

When the sun sets, the CTD gets a break, and the night crew focuses on zooplankton.

Part of the work of the LTER is to understand the way that these complex factors and processes influence primary productivity, phytoplankton, and the zooplankton community structure. In turn, inter-annual or long-term changes in phytoplankton and zooplankton community structure likely have consequences for vertebrates in and around the Gulf of Alaska, like seabirds, fish, marine mammals, and people. In other words, zooplankton community structure is one piece of understanding why the kittiwakes are or are not happy this spring. It seems that research on zooplankton communities requires, at least sometimes, to consider the perspective of a hungry bird.

Peering at a jar of copepods and euphausiids (two important types of zooplankton) we pulled up in the bongo nets last night, I was fascinated by the way they look and impressed by the amount of swimming, squirming life in the jar. My most common question about the plankton is usually some variation of “Is this …” or “What is this?” But the questions the LTER seeks to ask are a little more complex.

Considering the copepods and euphausiids, these researchers might ask, “How much zooplankton is present for food?” or “How high of quality is this food compared to what’s normal, and what does that mean for a list of potential predators?” or “How accessible and easy to find is this food compared to what’s normal, and what does that mean for a list of potential predators?” They might also ask “What oceanographic conditions are driving the presence and abundance of these particular zooplankton in this particular place at this particular time?” or “What factors are influencing the life stage and condition of these zooplankton?”

Euphausiids

Euphausiids (also known as krill) are among the types of zooplankton we collected with the bongo nets last night.

Copepods in a jar

Small copepods are among the types of zooplankton we collected with the bongo nets last night.

As we get ready for another night of sampling with the bongo nets, I am excited to look more closely at the fascinating morphology (body-shape) and movements of the unique and amazing zooplankton species. But I will also keep in mind some of the bigger picture questions of how these zooplankton communities simultaneously shape, and are shaped by, the dynamic Gulf of Alaska ecosystem. Over the course of the next 3 blogs, I plan to focus first on zooplankton, then zoom in to primary production and phytoplankton, and finally dive more into nutrients and oceanographic characteristics that drive much of the dynamics in the Gulf of Alaska.

 

Personal Log 

Life on the night shift requires a pretty abrupt change in sleep patterns. Last night, we started sampling around 10 pm and finished close to 4 am. To get our bodies more aligned with the night schedule, the four of us working night shift tried to stay up for another hour or so. It was just starting to get light outside when I headed to my bunk. Happily, I had no problem sleeping until 2:30 this afternoon! I’m hoping that means I’m ready for a longer night tonight, since we’ll be deploying the bongo nets in deeper water as we head offshore along the Middleton Line.

WWII shipwreck

While on Middleton Island, we marveled at a WWII shipwreck that has been completely overtaken by seabirds for nesting.

Shipwreck filled with plants

Inputs of seabird guano, over time, have fertilized the growth of interesting lichens, mosses, grasses, and even shrubs on the sides and top of the rusty vessel.

 

Did You Know?

Imagine you have a copepod that is 0.5 mm long and a copepod that is 1.0 mm long. Because the smaller copepod is half as big in length, height, and width, overall that smaller copepod at best offers only about 1/8th as much food for a hungry animal. And that assumes that it is as calorie-dense as the larger copepod.

 

Question of the Day:

Are PCBs biomagnifying in top marine predators in the Gulf of Alaska? Are there resident orca populations in Alaska that are impacted in similar ways to the Southern Resident Orca Whale population [in Puget Sound] (by things like toxins, noise pollution, and decreasing salmon populations? Is it possible for Southern Resident Orca Whales to migrate and successfully live in the more remote areas of Alaska? Questions from Lake Washington Girl’s Middle School 6th grade science class.

These are great questions! No one on board has specific knowledge of this, but they have offered to put me in contact with researchers that focus on marine mammals, and orcas specifically, in the Gulf of Alaska. I’ll keep you posted when I know more!

Mark Van Arsdale: What Makes Up an Ecosystem? Part III – Zooplankton, September 15, 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 15, 2018

Weather Data from the Bridge

Mostly cloudy, winds southerly 20 knots, waves to eight feet

57.56 N, 147.56 W (in transit from Gulf of Alaska Line to Kodiak Line)

Science Log

What Makes Up an Ecosystem? Part III Zooplankton

The North Gulf of Alaska Long-term Ecological Research Project collects zooplankton in several different ways.  The CalVET Net is dropped vertically over the side of the boat to a depth of 100 meters and then retrieved.  This net gives researchers a vertical profile of what is going on in the water column.  The net has very fine mesh in order to collect very small plankton.  Some of these samples are kept alive for later experiments. Others are preserved in ethanol for later genetic analysis. One of the scientists aboard is interested in the physiological details of what makes copepods thrive or not.  Copepods are so important to the food webs of the Gulf of Alaska, that their success or failure can ultimately determines the success or failure of many other species in the ecosystem.  When “the blob” hit the Gulf of Alaska in 2014-2016, thousands and thousands of sea birds died.  During those same years, copepods were shown to be less successful in their growth and egg production.

Chief Scientist Russ Hopcroft prepping the Multi-net

Chief Scientist Russ Hopcroft prepping the Multi-net

The second net used to collect zooplankton is the Multi-net.  We actually use two different Multi-nets.  The first is set up to do a vertical profile.  In the morning, it’s dropped vertically behind the boat.  Four or five times a night, we tow the second Multi-net horizontally while the boat moves slowly forward at two knots.  This allows us to collect a horizontal profile of plankton at specific depths.  If the water depth is beyond 200 meters, we will lower the net to that depth and open the first net.  The first net samples between 200 and 100 meters, above 100 meters we open the second net.  As we go up each net is opened in decreasing depth increments, the last one being very close to the surface.  Once the net is retrieved, we wash organisms down into the cod end, remove the cod end, and preserve the samples in glass jars with formalin. In a busy night, we may put away twenty-five pint-sized samples of preserved zooplankton.  When those samples go back to Fairbanks they have to be hand-sorted by a technician to determine the numbers and relative mass of each species.  We are talking hours and hours of time spend looking through a microscope.  One night of work on the Tiglax may produce one month of work for technicians in the lab.

 

Underwater footage of a Multi-net triggering.

The last type of net we use is a Bongo net.  Its steel frame looks like the frame of large bongo drums.  Hanging down behind the frame is two fine mesh nets, approximately seven feet long terminating in a hard plastic sieve or cod end.  Different lines use different nets based on the specific questions researchers have for that transect line or the technique used on previous years transects.   To maintain a proper time series comparison from year to year, techniques and tools have to stay consistent.

A cod end

A cod end

I’ve spent a little bit of time under the microscope looking at some of the zooplankton samples we have brought in. They are amazingly diverse. The North Gulf of Alaska has two groups of zooplankton that can be found in the greatest abundance: copepods and euphausiids (krill.)    These are food for most other animals in the North Gulf of Alaska.  Fish, seabirds, and baleen whales all eat them.  Beyond these two, I was able to observe the beating cilia of ctenophores and the graceful flight of pteropods or sea angels, the ghost-like arrow worms, giant-eyed amphipods, and dozens of others.

Deep sea squid, an example of a vertical migrator caught in our plankton trawls

Deep sea squid, an example of a vertical migrator caught in our plankton trawls

By far my favorite zooplankton to watch under the microscope was the larvae of the goose neck barnacle.  Most sessile marine organisms spend the early, larval stage of their lives swimming amongst the throngs of migrating zooplankton.  Barnacles are arthropods, which are defined by their exoskeletons and segmented appendages.  Most people would recognize barnacles encrusting the rocks of their favorite coastline, but when I show my students videos of barnacles feeding most are surprised to see the delicate feeding structures and graceful movements of this most durable intertidal creature.  When submerged, barnacles open their shells and scratch at particles in the water with elongated combs that are really analogous to legs. The larva of the goose neck barnacle has profusely long feeding appendages and a particularly beautiful motion as it feeds.

We have to “fish” for zooplankton at night for two reasons.  The first is logistical.  Some work needs to get done at night when the winch is not being used by the CTD team.  The second is biological.  Most of the zooplankton in this system are vertical migrators.  They rise each night to feed on phytoplankton near the surface and then descend back down to depth to avoid being seen in the daylight by their predators.  This vertical migration was first discovered by sonar operators in World War II.  While looking for German U-boats, it was observed that the ocean floor itself seemed to “rise up” each night.  After the war, better techniques were developed to sample zooplankton, and scientists realized that the largest animal migration on Earth takes place each night and each morning over the entirety of the ocean basins.


One of my favorite videos on plankton.

Personal Log

The color of water

This far offshore, the water we are traveling through is almost perfectly clear, yet the color of the ocean seems continuously in flux.  Today the sky turned gray and so did the ocean.  As the waves come up, the texture of the ocean thickens and the diversity of reflection and refraction increases.   Look three times in three directions, and you will see three hundred different shades of grey or blue.  If the sun or clouds change slightly, so does the ocean.

The sea is anything but consistent. Rips or streaks of current can periodically be seen separating the ocean into distinct bodies.  So far in our trip, calm afternoons have turned into windy and choppy evenings. Still, the crew tells me that by Gulf of Alaska standards, we are having amazing weather.

Variations in water texture created by currents in the Gulf of Alaska.

Variations in water texture created by currents in the Gulf of Alaska.

 

Did You Know?

The bodies of puffins are much better adapted to diving than flying.  A puffin with a full belly doesn’t fly to get out of the way of the boat so much as butterfly across the surface of the water.  Michael Phelps has nothing on a puffin flapping its way across the surface of the water.

 

Animals Seen Today

  • Fin and sperm whales in the distance
  • Storm Petrels, tufted puffins, Laysan and black-footed and short-tailed albatross, flesh footed shearwaters

Amanda Dice: Bongos in the Water, August 24, 2017

NOAA Teacher at Sea

Amanda Dice

Aboard NOAA Ship Oscar Dyson

August 21 – September 2, 2017

 

Mission: Juvenile Pollock Fishery Survey

Geographic area of cruise: Western Gulf of Alaska

Date: August 24, 2017

Weather Data: 11.5 C, Foggy

Latitude 56 35.5 N, Longitude 153 21.9 W

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This map on the bridge helps everyone keep track of where we are and where we are headed next.

Science and Technology Log

At each sampling site, we take two types of samples. First, we dip what are called bongo nets into the water off of the side of the boat. These nets are designed to collect plankton. Plankton are tiny organisms that float in the water. Then, we release long nets off of the back of the boat to take a fish sample. There is a variety of fish that get collected. However, the study targets five species, one of which is juvenile walleye pollock, Gadus chalcogrammus. These fish are one of the most commercially fished species in this area. I will go into more detail about how the fish samples are collected in a future post. For now, I am going to focus on how plankton samples are collected and why they are important to this survey.

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Juvenile walleye pollock are fish that are only a few inches long. These fish can grow to much larger sizes as they mature.

As you can see in the photos below, the bongo nets get their name because the rings that hold the nets in place resemble a set of bongo drums. The width of the nets tapers from the ring opening to the other end. This shape helps funnel plankton down the nets and into the collection pieces found at the end of the nets. These collection devices are called cod ends.

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Bongo nets being lowered into the water off of the side of the ship.

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This is the collection end, or cod end, of the bongo nets.

This study uses two different size bongo nets. The larger ones are attached to rings that are 60 centimeters in diameter. These nets have a larger mesh size at 500 micrometers. The smaller ones are attached to rings that are 20 centimeters in diameter and have a smaller mesh size at 150 micrometers. The different size nets help us take samples of plankton of different sizes. While the bongo nets will capture some phytoplankton (plant-like plankton) they are designed to mainly capture zooplankton (animal-like plankton). Juvenile pollock eat zooplankton. In order to get a better understanding of juvenile pollock populations, it is important to also study their food sources.

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Here I am, helping to bring the bongo nets back on to the ship.

Once the bongo nets have been brought back on board, there are two different techniques used to assess which species of zooplankton are present. The plankton in nets #1 of both the small and large bongo are placed in labeled jars with preservatives. These samples will be shipped to a lab in Poland once the boat is docked. Here, a team will work to identify all the zooplankton in each jar. We will probably make it to at least sixty sampling sites on the first leg of this survey. That’s a lot of zooplankton!

 

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A jar of preserved zooplankton is ready to be identified.

The other method takes place right on the ship and is called rapid zooplankton assessment (RZA). In this method, a scientist will take a small sample of what was collected in nets #2 of both the small and large bongos. The samples are viewed under a microscope and the scientist keeps a tally of which species are present. This number gives the scientific team some immediate feedback and helps them get a general idea about which species of zooplankton are present. Many of the zooplankton collected are krill, or euphausiids, and copepods. One of the most interesting zooplankton we have sampled are naked pteropods, or sea angels. This creature has structures that look very much like a bird’s wings! We also saw bioluminescent zooplankton flash a bright blue as we process the samples. Even though phytoplankton is not a part of this study, we also noticed the many different geometric shapes of phytoplankton called diatoms.

 

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A naked pteropod, or sea angel, as seen through the microscope.

Personal Log

Both the scientific crew and the ship crew work one of two shifts. Everyone works either midnight to noon or noon to midnight. I have been lucky enough to work from 6am – 6pm. This means I get the chance to work with everyone on board at different times of the day. It has been really interesting to learn more about the different ship crew roles necessary for a survey like this to run smoothly. One of the more fascinating roles is that of the survey crew. Survey crew members act as the main point of communication between the science team and the ship crew. They keep everyone informed about important information throughout the day as well as helping out the science team when we are working on a sample. They are responsible for radioing my favorite catchphrase to the bridge and crew, “bongos in the water.”

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A sign of another great day on the Gulf of Alaska.

Did You know?

You brush your teeth with diatoms! The next time you brush your teeth, take a look at the ingredients on your tube of toothpaste. You will see “diatomaceous earth” listed. Diatomaceous earth is a substance that contains the silica from ancient diatoms. Silica gives diatoms their rigid outer casings, allowing them to have such interesting geometric shapes. This same silica also helps you scrub plaque off of your teeth!

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Diatoms as seen through a microscope.

 

Christine Webb: August 19, 2017

NOAA Teacher at Sea

Christine Webb

Aboard NOAA Ship Bell M. Shimada

August 11 – 26, 2017

Mission: Summer Hake Survey Leg IV

Geographic Area of Cruise: Pacific Ocean from Newport, OR to Port Angeles, WA

Date: 8/19/2017

Latitude: 48.59 N

Longitude: 126.59 W

Wind Speed: 15 knots

Barometric Pressure: 1024.05 mBars

Air Temperature: 59 F

Weather Observations: Sunny

Science and Technology Log:

You wouldn’t expect us to find tropical sea creatures up here in Canadian waters, but we are! We have a couple scientists on board who are super interested in a strange phenomenon that’s been observed lately. Pyrosomes (usually found in tropical waters) are showing up in mass quantities in the areas we are studying. No one is positive why pyrosomes are up here or how their presence might eventually affect the marine ecosystems, so scientists are researching them to figure it out. One of the scientists, Olivia Blondheim, explains a bit about this: “Pyrosomes eat phytoplankton, and we’re not sure yet how such a large bloom may impact the ecosystem overall. We’ve already seen that it’s affecting fishing communities because their catches have consisted more of pyrosomes than their target species, such as in the shrimp industry.”

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Sorting through a bin of pyrosomes

Pyrosomes are a type of tunicate, which means they’re made up of a bunch of individual organisms. The individual organisms are called zooids. These animals feed on phytoplankton, and it’s very difficult to keep them alive once they’re out of the water. We have one alive in the wet lab right now, though, so these scientists are great at their jobs.

We’ve found lots of pyrosomes in our hake trawls, and two of our scientists have been collecting a lot of data on them. The pyrosomes are pinkish in color and feel bumpy. Honestly, they feel like the consistency of my favorite candy (Sour Patch Kids). Now I won’t be able to eat Sour Patch Kids without thinking about them. Under the right conditions, a pyrosome will bioluminesce. That would be really cool to see, but the conditions have to be perfect. Hilarie (one of the scientists studying them) is trying to get that to work somehow before the trip is over, but so far we haven’t been able to see it. I’ll be sure to include it in the blog if she gets it to work!

One of the things that’s been interesting is that in some trawls we don’t find a single pyrosome, and in other trawls we see hundreds. It really all depends on where we are and what we’re picking up. A lot of research still needs to be done on these organisms and their migration patterns, and it’s exciting to be a small part of that.

Personal Log:

The science crew continues to work well together and have a lot of fun! Last night we had an ice cream sundae party after dinner, and I was very excited about the peanut butter cookie dough ice cream. My friends said I acted more excited about that than I did about seeing whales (which is probably not true. But peanut butter cookie dough ice cream?! That’s genius!). After our ice cream sundaes, we went and watched the sunset up on the flying bridge. It was gorgeous, and we even saw some porpoises jumping in the distance.

It was the end to another exciting day. My favorite part of the day was probably the marine mammal watch where we saw all sorts of things, but I felt bad because I know that our chief scientist was hoping to fish on that spot. Still, it was so exciting to see whales all around our ship, and some sea lions even came and swam right up next to us. It was even more exciting than peanut butter cookie dough ice cream, I promise. Sometimes I use this wheel to help me identify the whales:

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Whale identification wheel

Now we’re gearing up for zooplankton day. We’re working in conjunction with the Nordic Pearl, a Canadian vessel, and they’ll be fishing on the transects for the next couple days. That means we’ll be dropping vertical nets and doing some zooplankton studies. I’m not exactly sure what that will entail, but I’m excited to learn about it! So far the only zooplankton I’ve seen is when I was observing my friend Tracie. She was looking at phytoplankton on some slides and warned me that sometimes zooplankton dart across the phytoplankton. Even though she warned me, it totally startled me to see this giant blob suddenly “run” by all the phytoplankton! Eeeeep! Hopefully I’ll get to learn a lot more about these creatures in the days coming up.