Geographic Area of Cruise: Northern Gulf of Alaska (Port: Seward)
Date: September 5, 2019
Weather Data from Bartlett High School Student Meteorologist Jack Pellerin
Time: 0730 Latitude: 61.2320° N Longitude: 149.7334° W Wind: Northwest, 2 mph Air Temperature: 11oC (52oF) Air pressure: 30.14 in Partly cloudy, no precipitation
Personal Introduction
On September 10th, I enter my 46th year on this amazing planet, and on the 11th, I depart on a trip that will be a birthday gift to remember. I will be departing Seward on U.S. Fish & Wildlife Service’s R/V Tiglax to assist in the Northern Gulf of Alaska Long-Term Ecological Research study. To understand why I am so excited about this trip, I have to rewind about 30 years.
On March 24th, 1989, I watched in shock, along with the world, as the oil from Exxon Valdez swept across Prince William Sound. I was a 15-year old budding scientist learning about the importance of baseline data for ecosystems. I didn’t know how, but I envisioned myself someday assisting in science research for this beautiful ecosystem. I dreamt of the day I would end up in Alaska and experience the Pacific Ocean.
In 2006, I was fortunate to be offered a teaching position in Cordova, Alaska on Prince William Sound where I became an oceanography and marine biology teacher. I was in awe of the ocean and what it had to teach myself and my students. Having the ocean at our front door made hands on learning in the field possible each and every week. We were also fortunate enough to partner with the U.S. Coast Guard Cutter (USCGC) Sycamore for a marine science field trip each year along with scientists from the Prince William Sound Science Center and U.S. Forest Service.
Showing zooplankton to a U.S. Coast Guard crew member after a plankton tow. Photo Credit: Allen Marquette
Since 2017, I have been teaching at Bartlett High School (BHS) in Anchorage School District. I again have the opportunity to teach oceanography and marine biology and I am thrilled. Although we live only a few miles away, many of my students have not yet seen the ocean. It is so important for me to make learning relevant to their lives and their locality. As much as we can incorporate Alaska and their cultures into the lessons the better.
Here are just a few snapshots from our classroom:
Students in my BHS marine biology class learn to make sushi during a lesson on seaweed uses.
BHS marine biology students examine zooplankton during the Kenai Fjords Marine Science Explorers program in Resurrection Bay.
Students in my BHS marine biology class operating mini-ROVs they built to complete an underwater rescue mission.
In a few days, I will begin my two-week mission to assist in important science research in Northern Gulf of Alaska (NGA) and I feel like my 30-year old dream has come true. I will be participating in the Long Term Ecological Research (LTER) study, which is funded by the National Science Foundation (NSF).
This cruise will be the third survey for the 2019 season for this area and the 23rd consecutive season for sampling along the Seward Line. The goal of the NGA-LTER program is to evaluate the ecosystem in terms of its productivity and its resiliency in the face of extreme seasonal variations and long term climate change. The mission entails doing a variety of water and plankton sampling at different stations along four transect lines in the NGA, as well as a circuit within Prince William Sound.
The NGA-LTER sampling stations. Image Credit: Russ Hopcroft
I will be sailing aboard R/V Tiglax (pictured below) which is the Aleut word for eagle and is pronounced TEKL-lah. My primary mission is to assist on the night shift with the collection of zooplankton at each station. In addition to this, I look forward to learning as much as I can about the other work being done, including water chemistry, nutrient sampling, phytoplankton collection and analysis, and seabird and mammal surveys. As a NOAA Teacher at Sea, I am tasked with creating lesson plans that connect this science research to my classroom. My goal is to develop lessons that will help my students understand the importance of whole systems monitoring, as well as the important connections between ocean water properties, microfauna and megafauna.
R/V Tiglax. Photo Credit: Robin Corcoran USFWS
When I am not in my classroom, I like to be outside as much as possible. I enjoy hiking, backpacking and spending time with my family on our remote property in Bristol Bay.
My husband and I getting ready to backpack Crow Pass Trail , part of the historic Iditarod Trail.
My husband and I also like to travel outside of Alaska whenever possible during the winter months and see the world. One of our favorite trips was completing a full transit of the Panama Canal. This winter break we will be headed to the barrier reef in Belize to experience the beautiful tropical ocean.
Transiting the Panama Canal on Christmas Day on our honeymoon.
I tell my students we have researched and explored more of space than we have of our own ocean.
Participating in Space Camp Academy during my tenure as 2012 Alaska Teacher of the Year.
I am so excited to be working to help change that statistic!
I am honored to be a NOAA Teacher at Sea.
Did You Know?
This summer has broken many records in Alaska for warm dry weather and Southcentral has been in an official drought. How will this impact ocean temperatures out in the NGA and will we see evidence in the plankton or other organisms we examine?
Stay tuned to my blog and I will let you
know the answer to this as well as so much more!
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.
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!
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!
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.”
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
Phytoplankton! These organisms are amazing. Like terrestrial plants, they utilize energy from the sun to photosynthesize, transforming water and carbon dioxide into sugars and oxygen. Transforming this UV energy into sugars allows photosynthetic organisms to grow and reproduce, then as they are consumed, the energy is transferred through the food web. With a few fascinating exceptions (like chemotrophs that synthesize sugars from chemicals!), photosynthetic organisms form the basis of all food webs. The ecosystems we are most familiar with, and depend upon culturally, socially, and economically, would not exist without photosynthetic organisms.
Indeed, productivity and health of species like fish, birds, and marine mammals are highly dependent upon the productivity and distribution of phytoplankton in the Gulf of Alaska. Phytoplankton also play an important role in carbon fixation and the cycling of nutrients in the Gulf of Alaska. For the LTER, developing a better understanding of what drives patterns of phytoplankton productivity is important to understanding how the ecosystem might change in the future. Understanding the basis of the food web can also can inform management decisions, such as regulation of fisheries.
Seawater captured at different depths by niskin bottles on the rosette transferred to bottles by different scientists for analysis.
To better understand these patterns, researchers aboard R/V Tiglax use the rosette on the CTD to collect water at different depths. The plankton living in this water is processed in a multitude of ways. First, in the lab on the ship, some of the water is passed through two filters to catch phytoplankton of differing sizes. These filters are chemically extracted for 24 hours before being analyzed using a fluorometer, which measures the fluorescence of the pigment Chlorophyll-a. This provides a quantitative measurement of Chlorophyll-a biomass. It also allows researchers to determine whether the phytoplankton community at a given time and place is dominated by ‘large’ phytoplankton (greater than 20 microns, predominantly large diatoms) or ‘small’ phytoplankton (less than 20 microns, predominantly dinoflagellates, flagellates, cryptophyte algae, and cyanobacteria).
Preparing filters to separate large and small phytoplankton from the seawater samples.
For example, waters in Prince William Sound earlier in the week had a lot of large phytoplankton, while waters more offshore on the Seward Line were dominated by smaller phytoplankton. This has important ramifications for trophic interactions, since many different consumers prefer to eat the larger phytoplankton. Larger phytoplankton also tends to sink faster than small plankton when it dies, which can increase the amount of food reaching benthic organisms and increase the amount of carbon that is sequestered in ocean sediments.
The Chlorophyll-a biomass measurements from the fluorometer are a helpful first step to understanding the biomass of phytoplankton at stations in the Gulf of Alaska. However, research here and elsewhere has shown that the amount of carbon fixed by phytoplankton can vary independently of the Chlorophyll-a biomass. For example, data from 2018 in the Gulf of Alaska show similar primary productivity (the amount of carbon fixed by phytoplankton per day) in the spring, summer, and fall seasons even though the Chlorophyll-a biomass is much higher in the spring. This is likely because of at least two overlapping factors. Vertical mixing in the winter and spring, driven primarily by storms, brings more nutrients and iron into the upper water column. This higher nutrient and iron availability in the spring allow for the growth of larger phytoplankton that can hold more chlorophyll. This vertical mixing also means that phytoplankton tend to get mixed to greater depths in the water column, where less light is available. To make up for this light limitation, the phytoplankton produce more chlorophyll in the spring so they can more effectively utilize the light that is available. This variation in chlorophyll over the seasons probably helps to make the phytoplankton community overall more productive, but it makes it problematic to use Chlorophyll-a biomass (which is relatively easy to measure) as a proxy for primary productivity (which is much more challenging to measure).
A sample of filtered, extracted phytoplankton is placed into the fluorometer.
To address the question of primary productivity more directly, researchers are running an experiment on the ship. Seawater containing phytoplankton from different depths is incubated for 24 hours. The container for each depth is screened to let in sunlight equivalent to what the plankton would be exposed to at the depth they were collected from. Inorganic carbon rich in C13 isotope is added to each container as it incubates. After 24 hours, they filter the water and measure the amount of C13 the phytoplankton have taken up. Because C13 is rare in ecosystems, this serves as a measurement of the carbon fixation rate – which can then be converted into primary productivity.
Phytoplankton samples from the rosette are also preserved for later analysis in various labs onshore. Some of the samples will be processed using High Performance Light Chromotography, which produces a pigment profile. These pigments are not limited to Chlorophyll-a, but also include other types of Chlorophyll, Fucoxanthin (a brownish pigment found commonly in diatoms as well as other phytoplankton), Peridinin (only found in photosynthetic dinoflagellates), and Diadinoxanthin (a photoprotective pigment that absorbs sunlight and dissipates it as heat to protect the phytoplankton from excessive exposure to sunlight). The pigment profiles recorded by HPLC can be used to determine which species of plankton are present, as well as a rough estimate of their relative abundance.
A different lab will also analyze the samples using molecular analysis of ribosomal RNA. There are ID sequences that can be used to identify which species of phytoplankton are present in the sample, and also get a rough relative abundance. Other phytoplankton samples are preserved for microscopy work to identify the species present. Microscopy with blue light can also be used to investigate which species are mixotrophic – a fascinating adaptation I’ll discuss in my next blog post!
It is a lot of work, but all of these various facets of the phytoplankton research come together with analysis of nutrients, iron, oxygen, dissolved inorganic carbon, temperature, and salinity to answer the question “What regulates the patterns of primary productivity in the Gulf of Alaska?”
There are already many answers to this question. There is an obvious seasonal cycle due to light availability. The broad pattern is driven by the amount of daylight, but on shorter time-scales it is also affected by cloud cover. As already mentioned, vigorous vertical mixing also limits the practical light availability for phytoplankton that get mixed to greater depths. There is also an overall, declining gradient in primary productivity moving from the coast to the deep ocean. This gradient is probably driven most by iron limitation. Phytoplankton need iron to produce chlorophyll, and iron is much less common as you move into offshore waters. There are also finer-scale spatial variations and patchiness, which are partly driven by interacting currents and bathymetry (ocean-bottom geography). As currents interact with each other and features of the bathymetry, upwelling and eddies can occur, affecting such things as nutrient availability, salinity, water temperature, and intensity of mixing in the water column.
The early-morning view from station GAK on the ‘Seward Line.’ Patterns of primary productivity are driven both by amount of cloud cover and amount of daylight. During our two weeks at sea, we actually sampled at GAK1 3 separate times. The amount of daylight (time between sunrise and sunset each day) at this location increased by nearly 60 minutes over the two week cruise!
The current work seeks to clarify which of these factors are the most dominant drivers of the patterns in the Gulf of Alaska and how these factors interact with each other. The research also helps to determine relationships between things that can be more easily measured, such as remote-sensing of chlorophyll, and the types of data that are particularly important to the LTER in a changing climate but are difficult to measure across broad spatial scales and time scales, such as primary productivity or phytoplankton size community. Phytoplankton are often invisible to the naked eye. It would be easy to overlook them, but in many ways, phytoplankton are responsible for making the Gulf of Alaska what it is today, and what it will be in the future. Understanding their dynamics is key to deeper understanding of the Gulf.
Personal Log
The schedule along the Seward Line and as we head to the Kodiak Line had to be adjusted due to rough seas and heavy winds. This means we have been working variable and often long hours on the night shift. It is usually wet and cold and dark, and when it is windy the seawater we use to hose down the zooplankton nets seems to always spray into our faces and make its way into gloves and up sleeves. But we still manage to have plenty of fun on the night shift and share lots of laughs. There are also moments where I look up from the task at hand and am immersed in beauty, wonder, and fascination. I get to watch jellies undulate gracefully off the stern (all the while, crossing my fingers that they don’t end up in our nets — that is bad for both them and us) and peer more closely at the zooplankton we’ve caught. I am mesmerized by the color and motion of the breaking waves on a cloudy dawn and delighted by the sun cascading orange-pink towards the water at sunset. I am reminded of my love, both emotional and intellectual, for the ocean!
We experienced a lot of wind, rain, waves, and spray from the high-pressure hose (especially when I was wielding the hose), but bulky float coats kept us mostly warm and dry.
Did You Know?
Iron is the limiting nutrient in many offshore ecosystems. Where there is more iron, there is generally more primary productivity and overall productive ecosystems. Where there is little iron, very little can grow. This is different than terrestrial and even coastal ecosystems, where iron is plentiful and other nutrients (nitrogen, phosphorous) tend to be the limiting factors. Because people worked from what they knew in terrestrial ecosystems, until about 30 years ago, nitrogen and phosphorous were understood to be the important nutrients to study. It was groundbreaking when it was discovered that iron may be a crucial piece of the puzzle in many open ocean ecosystems.
Question of the Day:
Regarding sustainability and scalability of intensive ocean resource harvesting: If humans started eating plankton directly, what could happen? And a follow-up: Can we use algae from harmful bloom areas?
Question from Leah Lily, biologist, educator, and qualitative researcher, Bellingham, WA
I first shared this question with the zooplankton night crew. The consensus was that it was not a good idea to harvest zooplankton directly for large-scale human consumption. Some krill and other zooplankton are already harvested for ‘fish oil’ supplements; as demand increases, the sustainability of this practice has become more dubious. The zooplankton night crew were concerned that if broader-scale zooplankton harvest were encouraged, the resource would quickly be overharvested, and that the depletion of zooplankton stocks would have even more deleterious consequences for overall ecosystem function than the depletion of specific stocks of fish. They also brought up the question of how much of each zooplankton would actually be digestible to humans. Many of these organisms have a chitinous exoskeleton, which we wouldn’t be able to get much nutrition from. So it seems like intensive ocean harvesting of zooplankton is likely not advisable.
However, when I talked with the lead phytoplankton researcher on board, she thought there might be slightly more promise in harvesting phytoplankton. It is more unlikely, she thinks, that it would get rapidly depleted since there is so much phytoplankton out there dispersed across a very wide geographic scale. Generally, harvesting lower on the food chain is more energy efficient. At every trophic level, when one organism eats another, only a fraction of the energy is utilized to build body mass. So the higher up the food web we harvest from, the more energy has been ‘lost’ to respiration and other organism functions. Harvesting phytoplankton would minimize the amount of energy that has been lost in trophic transfer. Unlike most zooplankton, most phytoplankton is easily digestible to people and is very rich in lipids and proteins. It could be a good, healthy food source. However, as she also pointed out, harvesting phytoplankton in the wild would likely require a lot of time, energy, and money because it is generally so sparse. It likely would not be economically feasible to filter the plankton in the ocean out from the water, and, with current technologies, not particularly environmentally friendly. Culturing, or ‘farming,’ phytoplankton might help to address these problems, and in fact blue-green algae/Spirulina is already grown commercially and available as a nutritional supplement. And there may be some coastal places where ‘wild’ harvest would be practical. There are a number of spots where excess nutrients, often from fertilizers applied on land that runoff into streams and rivers, can cause giant blooms of phytoplankton. These are often considered harmful algal blooms because as the phytoplankton die, bacteria utilize oxygen to decompose them and the waters become hypoxic or anoxic. Harvesting phytoplankton from these types of harmful algal blooms would likely be a good idea, mitigating the impacts of the HABs and providing a relatively easy food source for people. However, it would be important to make sure that toxin-producing plankton, such as Alexandrium spp. (which can cause paralytic shellfish poisoning) were not involved in the HAB.
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.
Black-legged kittiwakes are visible through the observation windows in the nesting tower on Middleton Island.
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.
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.
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 (also known as krill) are among the types of zooplankton we collected with the bongo nets last night.
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.
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!
During the last two weeks, scientists aboard the Tiglax will have done over 60 CTD casts, 60 zooplankton tows, measured over one thousand jellies caught Methot Net tows, and collected hundreds of water and chlorophyll samples. What happens with all of this data when we get back? The short answer is a lot more work. Samples have to be analyzed, plankton have to be counted and measured, DNA analysis work has to be done, and cohesive images of temperature, salinity, and nutrients have to be stitched together from the five different transects.
Preparing for another CTD cast. More than 60 CTD casts were made during our cruise.
Much of this data will eventually be entered into a computer model. I’ve spent a great deal of time talking with one of the scientists on aboard about how models can be used to answer essential scientific questions about how the Gulf of Alaska works. Take Neocalanus, the copepods we collected yesterday, for example. A scientist could ask the question, what factors determine a good versus bad year for Neocalanus? Or what are the downstream effects on a copepod species of an anomalous warming event like “the blob” of 2014-2015? A model allows you to make predictions based on certain parameters. You can run numerous scenarios, all with different possible variables, in very short periods of time. A model won’t ever predict the future, but it can help a scientist understand the “rules” that govern how the system works. But a model is only as good as its baseline assumptions, and those assumptions require the collection of real world data. A computer doesn’t know how fast Neocalanus grows under optimal or sub-optimal conditions unless you tell it, and to tell it, a scientist has to first measure it.
The fishing industry is a billion-dollar piece of the Alaskan economy. The ocean is getting warmer and more acidic. Food webs are shifting, and the abundance and distribution of the species we depend upon are changing as a result. Using models may allow us to better predict what sustainable levels of fish catches will be as conditions in the Gulf of Alaska change.
I also asked the scientists on board about the future of oceanography in light of the advancements in autonomous unmanned vehicles. Do you still need to send people out to sea when sending a Slocum Glider or Saildrone can collect data much cheaper than a ship filled with twenty scientists? The answer I got was, “No, at best these technologies will enhance but not replace what we do at sea. There will always be a place for direct scientific observations.” We still need oceanographers at sea.
In twenty-one years of teaching I have had lots students go on to be doctors, PA’s, nurses, micro-biologists, geneticists, and a variety of other scientific occupations, but no oceanographers. I guess I still have some work to do.
Personal Log
The Weather Finally Gets Us
We have had a few showers, bits of wind and waves, but the weather has been remarkably good for a cruise through the North Gulf of Alaska in late September. This morning, during the night shift the winds started to blow, it started to rain, and the waves came up. When I went to bed around six AM, the wind was blowing thirty knots, and when I woke up at eleven, it was pushing up some pretty rough seas. Things got really crazy after lunch. The winds were being channeled right down Night Island Passage and all work was put to a stop. I retired to my bunk to read, unable to even go outside and take look. They eventually battened down the hatches; and we changed course to go hide in a bay sheltered from the wind. (Yes, they really do say batten down the hatches.)
By dinner time decisions were made to not work for the night. It looked better where we were, but the stations we needed to sample were exposed to winds that were still blowing. No zooplankton sampling for the night meant that it was time to start washing, disassembling, and drying nets. We used seventeen different nets to sample zooplankton during the course of this trip and all of them needed to be washed and cared for before they got packed up.
Plankton nets hanging to dry (oceanographer laundry.)
Tomorrow we will begin the journey home with two stations un-sampled. The storm kept us from getting to the last stations, and another storm is just a few days away. Once the decision was made, I think we were all relieved to be heading in. Doing oceanography is hard work, and being away from lives, work, and family for such extended periods of time is tough. Some of the scientists on board have spent as much as six or eight weeks at sea this year. Having been out here for two weeks, I now understand what commitment that takes.
Unless something really interesting happens tomorrow, this will be my last blog. This trip has been personally challenging, but a rich experience, and I believe it will be formative to my teaching. I have learned a great deal about oceanography in general, and the Gulf of Alaska in particular. The Gulf of Alaska is a magical place. There is life almost everywhere you look. More than anything I will leave with a deep impression of the dedication that scientists give to the accuracy and integrity of their work.
[Postscript: Zooplankton and jelly work was done, so I was able to spend the entire last day on the flying bridge. There was a good amount of swell from the previous day’s storm, but the sun and scenery made it an enjoyable trip back to Seward. As we left Prince William Sound we were greeted by an abundance of seabirds that had been blown into the Sound by the weather. On that day, we documented almost as many species as the rest of the trip combined. We also got to watch a large group of orcas patrolling the area around Danger Island at the entrance to the Sound. We made our way back to GAK1. If the weather allows, GAK1 is always sampled at the beginning and ending of any trip. The weather was beautiful, Bear Glacier and the entrance to Resurrection Bay was alive with color, and I was going home. It was a great day.]
Views of the southern coast of the Kenai Peninsula as we traveled from Prince William Sound back to Seward.
