zooplankton – NOAA Teacher at Sea Blog

January 10, 2025January 10, 2025

Kiersten Newtoff: It Takes Two to Bongo, January 10, 2025

NOAA Teacher at Sea
Kiersten Newtoff
Aboard NOAA Ship Pisces
January 6 – January 29, 2025

Mission: Atlantic Marine Assessment Program for Protected Species (AMAPPS)
Geographic Area of Cruise: North Atlantic Coast
Date: January 10, 2025
Current Location: 37° 35.83 N, 73° 39.83 W (you can follow us at Windy in real time!)
Weather from the Bridge: Waves are 3-5ft, 42°F, wind speed of 15.8kn, and we are traveling 9.9knph.

What is Zooplankton?

If you ask someone what their favorite marine animal is, I guarantee it’s either dolphins, whales, turtles, or sharks. And honestly, you can’t really blame them. The term charismatic megafauna exists for a reason. Fortunately, these animals have used their charisma to inspire us to protect them and their habitat. While they have been great stewards for conservation, they don’t tell the whole story of what’s happening in the ecosystem.

a close-up view of the bottom of a sample jar filled with krill in water; the tiny crustaceans, resemble small white shrimps, have piled up at the bottom — One example of zooplankton is small krill, as seen in this sample container.

While some of the research groups on the Pisces are focused on marine mammals and seabirds, The Bongonauts focus on zooplankton. Plankton just refers to any organism in the water that can’t swim against a current and ‘floats’ in the water column. You can then further split plankton into animal-like (zooplankton) or plant-like (phytoplankton). The marine food chain starts with phytoplankton, which get consumed by zooplankton, which might get directly eaten by a baleen whale, like humpbacks. Zooplankton may also get eaten by small fishes then larger fish that eventually are consumed by toothed whales. Identifying and quantifying the abundance of zooplankton helps us to understand the health of the food chain. There really aren’t any “Save the Zooplankton” movements happening because let’s be honest, it’s hard to get people to like microscopic organisms. But their downfall due to changes in ocean temperature, salinity, and currents will permeate to the top of the food chain of whales, dolphins, and other megafauna. If we wish to protect the ‘cute’ species, we need to protect their food too!

Let’s Get Ready to Bongo!

Here enters the bongo. If you’ve played Donkey Kong, then you already know what a bongo is. A bongo is a set of two drums that are connected in the middle. In the marine world, what we do is beat on this drum set on the side of the boat and collect all the zooplankton that jump out of the water into collection buckets.

………………………..

Just kidding! But that would be cool.

Although we don’t have the musical bongo, we do have a plankton bongo! It was so named because there are two frames connected in the middle supporting the two plankton nets, kind of like a bongo drum. The nets are made of a mesh with openings that are 1/3 mm. As the nets travel in the water, the water can move through the mesh but larger organisms like zooplankton can’t. Part of the bongo apparatus is the CTD, which uses a series of sensors to measure conductivity, temperature, and depth. These oceanographic variables can help to explain the zooplankton communities we see.

a crewmember wearing an orange float coat and white hard hat looks over the rail of the ship as the paired bongo nets rise out of the water. It is nighttime, and we can only see a patch of the dark water illuminated by the ship's lights. A scientific probe is attached to the cable hoisting the paired nets. — (Left) A bongo net is coming out of the water. The device you see on the rope is the CTD, (Right) The zooplankton team gets lots of support in deploying the bongo nets from the deck crew. Pictured (left to right): Amanda, Tanya, Tasha, and Kiersten.

Four women in float coats or life vests, reflective gear, tall boots, and hard hats pose for a photo on the aft deck of the ship. The paired bongo nets lay spread out on the deck. It is nighttime. — (Left) A bongo net is coming out of the water. The device you see on the rope is the CTD, (Right) The zooplankton team gets lots of support in deploying the bongo nets from the deck crew. Pictured (left to right): Amanda, Tanya, Tasha, and Kiersten.

Bongo time is during the evening and is deployed in the same general areas as the cetacean observations earlier in the day. This allows the scientists to make correlations between plankton communities and the cetaceans spotted earlier. We release the bongos in the evening as the speed needed for a successful deployment is around 3 knots, whereas the observation teams need to be at a minimum of 8 knots. Also, many zooplankton undergo a diel vertical migration (move upwards) in the evening, making it more likely to get a representative sample of zooplankton from the entire water column.

Bongos, a Haiku
gliding through water
collect plankton by bongo
hopefully, cool things

Meet the Bongonauts

a woman wearing an orange float coat and a white hard hat sits at a computer desk and looks at an array of monitors. — Amanda monitors the depth of the bongo so she can communicate with the boatswain when to start hauling it back to the boat.

On this cruise, Amanda and Lily make up the zooplankton team. Amanda is a Biological Science Technician and has been working with NOAA since 2018. During her undergraduate studies, she spent a semester abroad focused on marine science. As soon as she finished, she immediately began looking for marine jobs. Her first position was with NOAA focusing on commercial fisheries. A few years later in 2021, her contracting company had another position within NOAA that she switched to and started focusing on zooplankton. One of the coolest things she’s seen in a bongo net was a strawberry squid, but don’t worry, it was promptly returned to the seas. She enjoys working with other groups on the science team to see what they are finding, and every time the nets come up there is excitement over what they may contain.

a woman lifts one sample jar out of a divided cardboard box and gazes down at the contents. Other jars in the boxes are topped with black lids and printed, detailed labels. — Lily examines the plankton spoils. Some are preserved in ethanol and others in formalin.

Lily is currently a sophomore at the Massachusetts Maritime Academy. The professor in one of her classes shared with her the opportunity to sail with the Pisces to volunteer on the zooplankton team and she took it up! Her future career goal is to understand the environmental impacts of cruise ships in port. Further along the line, she would like to get a Master’s in Library Science and be a children’s librarian. She chose Mass Maritime for their marine science program; other schools with similar programs were out of state or prohibitively expensive, but she feels like she’s made the right choice. Of all the things she’s told me, Mass Maritime seems really cool and gives lots of hands-on experience to their students.

Advice for Students

Amanda and Lily shared some of their insights for students who may want to work for NOAA some day.

Look for jobs on Indeed and LinkedIn. If you are already working with a company, see if they have other positions that you might like.
If you’re interested in marine science, go to a school that specializes in it. Avoid institutions that have it as a small program or just a minor, as you likely won’t be getting nearly as much hands-on experience as a school dedicated to it.
Keep your opportunities open – you might think you like Marine Science now but that may change as you do field work.
Even if an opportunity comes up that is not related to marine science, do things to give you any sort of field experience.
You can volunteer with NOAA! There are lots of programs to explore.

September 25, 2019

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.

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.

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.

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.

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.*

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!

July 5, 2019

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!

Boots
Hard hat
Life vest
Cat on Deck

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).

May 15, 2019May 15, 2019

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: 57^o34.6915’
Longitude: 150^o 06.9789’
Wind: 18 knots, South
Seas: 4-6 feet
Air Temperature: 46^oF (8^oC)
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).

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.”

April 30, 2019May 3, 2019

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: 59^o 39.0964’ N
Longitude: 146^o05.9254’ W
Wind: Southeast, 15 knots
Air Temperature: 10^oC (49^oF)
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?”

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.

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 1/8^th 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 6^th 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!