Author: Rachel Kaplan

The Dark Side of Upwelling: It’s getting harder and harder to breathe off the Oregon coast

By Rachel Kaplan, PhD candidate, Oregon State University College of Earth, Ocean, and Atmospheric Sciences and Department of Fisheries, Wildlife, and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab

The depths of the productive coastal Oregon ecosystem have long held a mystery – an increasing paucity in the concentration of dissolved oxygen at depth. When dissolved oxygen concentrations dips low enough, the condition “hypoxia” can alter biogeochemical cycling in the ocean environment and threaten marine life. Essentially, organisms can’t get enough oxygen from the water, forcing them to try to escape to more favorable waters, stay and change their behavior, or suffer the consequences and potentially suffocate.

Recent work has illuminated the cause of this mysterious rise in hypoxic waters: an increase in the wind-driven oceanographic process of upwelling (Barth et al., 2024). The seasonal upwelling of cold, nutrient-rich waters underlies the incredible productivity of the Oregon coast, but its dark twin is hypoxia: when organic material in the upper layer of the water column sinks, microbial respiration processes consume dissolved oxygen in the surrounding water. In addition, the deep waters brought to the surface by upwelling are depleted in oxygen compared to the aerated surface waters. These effects combine to form an oxygen-poor water layer over the continental shelf, which typically lasts from May until October in the Northern California Current (NCC) region. The spatial extent of this layer is highly variable – hypoxic bottom waters cover 10% of the shelf in some years and up to 62% in others, presenting challenging conditions for life occupying the Oregon shelf (Peterson et al., 2013).

Figure 1. An article in The Oregonian from 2004 documents research on a hypoxia-driven “dead zone” off the Oregon coast.

While effects of hypoxia on benthic communities and some fish species are well-documented, is unclear how increasing levels of hypoxia off Oregon may impact highly mobile, migratory organisms like whales. A primary pathway is likely through their prey – particularly species that occupy hypoxic regions and depths, like the zooplankton krill. Over the continental shelf and slope, which are important krill habitat, seasonally hypoxic waters tend to extend from about 150 meters depth to the bottom. The vertical center of krill distribution in the NCC region is around 170 meters depth, suggesting that these animals encounter hypoxic conditions regularly.

Interestingly, the two main krill species off the Oregon coast, Euphausia pacifica and Thysanoessa spinifera, use different strategies to deal with hypoxic conditions. Thysanoessa spinifera krill decrease their oxygen consumption rate to better tolerate ambient hypoxia, a behavioral modification strategy called “oxyconformity”. Euphausia pacifica, on the other hand, use “oxyregulation” to maintain the same, quite high, oxygen utilization rate regardless of ambient levels – which may indicate that this species will be less able to tolerate increasingly hypoxic waters (Tremblay et al., 2020).

Figure 2. This figure from Barth et al. 2024 maps the concentration of dissolved oxygen (uM/kg; cooler colors indicate less dissolved oxygen) to show an increase in hypoxic conditions over the continental shelf and slope (green and blue colors) across seven decades in the NCC region.

Over long time scales, such environmental pressures shape species physiology, life history, and evolution. The krill species Euphausia mucronate is endemic to the Humboldt Current System off the coast of South America, which includes a region of year-round upwelling and a persistent Oxygen Minimum Zone (OMZ). Fascinatingly, Humboldt krill can live in the core of the OMZ, using metabolic adaptations that even let them survive in anoxic conditions (i.e., no oxygen in the water). Humboldt krill abundances actually increase with shallower OMZ depths and lower levels of dissolved oxygen, pointing to the huge success of this species in evolving to thrive in conditions that challenge other local krill species (Díaz-Astudillo et al., 2022).

Back home in the NCC region, will Euphausia pacifica and Thysanoessa spinifera be pressured to adapt to continually increasing levels of hypoxia? If so, will they be able to adapt? One of krill’s many superpowers is an ability to tolerate a wide range of environmental conditions, including the dramatic gradients in temperature, water density, and dissolved oxygen that they encounter during their daily vertical migrations through the water column. Both species have strategies to deal with hypoxic conditions, and this capacity has allowed them to thrive in the active upwelling region that is the NCC. Now, the question is whether increasingly hypoxic waters will eventually force a threshold that compromises the capacity of krill to adapt – and then, what will happen to these species, and the foragers dependent on them?

References

Barth, J. A., Pierce, S. D., Carter, B. R., Chan, F., Erofeev, A. Y., Fisher, J. L., Feely, R. A., Jacobson, K. C., Keller, A. A., Morgan, C. A., Pohl, J. E., Rasmuson, L. K., & Simon, V. (2024). Widespread and increasing near-bottom hypoxia in the coastal ocean off the United States Pacific Northwest. Scientific Reports, 14(1), 3798. https://doi.org/10.1038/s41598-024-54476-0

Díaz-Astudillo, M., Riquelme-Bugueño, R., Bernard, K. S., Saldías, G. S., Rivera, R., & Letelier, J. (2022). Disentangling species-specific krill responses to local oceanography and predator’s biomass: The case of the Humboldt krill and the Peruvian anchovy. Frontiers in Marine Science, 9, 979984. https://doi.org/10.3389/fmars.2022.979984

Peterson, J. O., Morgan, C. A., Peterson, W. T., & Lorenzo, E. D. (2013). Seasonal and interannual variation in the extent of hypoxia in the northern California Current from 1998–2012. Limnology and Oceanography, 58(6), 2279–2292. https://doi.org/10.4319/lo.2013.58.6.2279

Tremblay, N., Hünerlage, K., & Werner, T. (2020). Hypoxia Tolerance of 10 Euphausiid Species in Relation to Vertical Temperature and Oxygen Gradients. Frontiers in Physiology, 11, 248. https://doi.org/10.3389/fphys.2020.00248

It’s getting hot in here: studying the impacts of marine heatwaves on krill, life-blood of the ocean

By Kim Bernard, Associate Professor, Oregon State University College of Earth, Ocean, and Atmospheric Sciences

Euphausiids, commonly known as “krill”, represent a globally distributed family of pelagic crustacean zooplankton, spanning from tropical to polar oceans. These remarkable organisms inhabit a vast range of marine habitats, from nearshore coastal waters to the expansive open ocean, and from the sea surface to abyssal depths. Notably, they claim the title of the largest biomass among non-domestic animal groups on Earth! Beyond their sheer abundance, euphausiids play a pivotal role in shaping global marine food webs, supporting both economically significant fisheries and extensive populations of marine megafauna.

Figure 1: Nyctiphanes australis. Photo credit: A. Slotwinski, CSIRO.

As our planet continues to warm, the ongoing and anticipated shifts in the distribution and biomass of krill populations herald potential disruptions to marine ecosystems and food webs globally. Marine heatwaves, which are expected to increase in frequency, intensity, and duration in the coming decades, have a significant impact on global krill populations, with knock-on effects through food webs. At our home-base off the coast of Oregon, a severe marine heatwave in 2014-2016 resulted in altered krill distributions and reduced biomass, causing a suite of ecological implications ranging from decline in salmon health to increased occurrence of whale entanglements in fishing gear (Daly et al. 2017; Santora et al. 2020).

Figure 2: (A) Simrad EK80 transducers (the larger one is a 38kHz transducer, the smaller is a 120kHz transducer) mounted to a pole that gets lowered into the water during our daily surveys. The transducers emit sound waves that bounce off objects, like krill, in the water and return to the instrument’s transceiver, allowing us to map krill within the water column. (B) The acoustic data collected by the echosounder appears in real-time on our computer screen allowing us to find krill that we can then target with the Bongo net. Photo credits: Kim Bernard.

Here, off the coast of New Zealand, the krill species Nyctiphanes australis (Figure 1) is an important prey item for many marine predators, including slender tuna (Allothunnus fallai), Australian salmon (Kahawai, Arripis trutta), Jack mackerel (Trachurus declivis), short-tailed shearwater (Puffinus tenuirostris) (O’Brien 1988), and of course, the reason we are out here, blue whales (Balaenoptera musculus brevicauda) (Torres et al. 2020). In a precursor study to the SAPPHIRE project, members of our current research team demonstrated the potential negative impacts that marine heatwaves can have off the coast of New Zealand. During that study, our team noted declines in the abundance and changes in the distribution patterns of Nyctiphanes australis during a marine heatwave compared to normal conditions, with subsequent negative impacts on the distribution and behavior of the local New Zealand blue whale population (Barlow et al. 2020). The impetus of the SAPPHIRE project is to improve our understanding of the physiological mechanisms underlying the observed changes in both krill and blue whale populations, with the goal to better predict future changes.

As a zooplankton ecologist and “kriller”, my role on the SAPPHIRE project is to further our knowledge on the prey, Nyctiphanes australis. There are several components to this part of our research: (1) mapping distribution patterns of krill, (2) measuring the quality of krill as prey to whales, and (3) running experiments to test how warming affects krill physiology. To map the krill distribution patterns, we are using active acoustics (Figure 2). To measure the quality of krill, we first need to collect them, and we do that using a Bongo net (Figure 3) that gets towed behind the boat targeting krill we find using the echosounder.

Figure 3: Kim Bernard and Ngatokoa Tikitau empty the contents of one of the Bongo net cod-ends into a bucket to examine the catch. Unfortunately, it was not filled with krill as we had hoped, but rather a gelatinous zooplankton known as Salpa democratica. Photo credit: KC Bierlich.

Once we have the krill, we’ll flash freeze them in liquid nitrogen and take them back to Oregon where we’ll measure the amount of protein, fats (lipids), and calories each one contains. Finally, for the experiments on temperature effects, we will use live krill collected with the Bongo net placed individually into 1L Nalgene bottles, each outfitted with oxygen sensors so that we can measure the respiration rates of krill at a range of temperatures they would experience during normal conditions and marine heatwaves (Figure 4).

Figure 4: Respiration experiment set-up with two circulating waterbaths in the foreground feeding two temperature treatments in coolers (aka “chilly bins”) behind. Once we catch krill (which has yet to happen), we will use this set-up to test the effects of warming on krill respiration rates. Photo credit: Kim Bernard.


References

Barlow DR, Bernard KS, Escobar-Flores P, Palacios DM, Torres LG (2020) Links in the trophic chain: modeling functional relationships between in situ oceanography, krill, and blue whale distribution under different oceanographic regimes. Marine Ecology Progress Series 642:207-225. https://doi.org/10.3354/meps13339

Daly EA, Brodeur RD, Auth TD (2017) Anomalous ocean conditions in 2015: impacts on spring Chinook salmon and their prey field. Marine Ecology Progress Series 566:169-182. https://doi.org/10.3354/meps12021

O’Brien DP (1988) Surface schooling behaviour of the coastal krill Nyctiphanes australis (Crustacea: Euphausiacea) off Tasmania, Australia. Marine Ecology Progress Series 42: 219-233.

Santora JA, Mantua NJ, Schroeder ID, Field JC, Hazen EL, Bograd SJ, Sydeman WJ, Wells BK, Calambokidis J, Saez L, Lawson D, Forney KA (2020) Habitat compression and ecosystem shifts as potential links between marine heatwave and record whale entanglements. Nature Communications 11(1):536. doi: 10.1038/s41467-019-14215-w.

Torres LG, Barlow DR, Chandler TE, Burnett JD. 2020. Insight into the kinematics of blue whale surface foraging through drone observations and prey data. PeerJ 8:e8906 https://doi.org/10.7717/peerj.8906

Oceanographic Alchemy: How Winds Become Whale Food in Oregon

By Rachel Kaplan, PhD student, Oregon State University College of Earth, Ocean, and Atmospheric Sciences and Department of Fisheries, Wildlife, and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab

Here in the GEMM lab, we love the Oregon coast for its amazing animals – the whales we all study, the seabirds we can sometimes spot from the lab, and the critters that come up in net tows when we’re out on the water. Oregonians owe the amazing biological productivity of the Oregon coast to the underlying atmospheric and oceanographic processes, which make our local Northern California Current (NCC) ecosystem one of the most productive places on earth.

While the topographical bumps of the Oregon coastline and vagaries of coastal weather do have a big impact on the physical and biological processes off the coast, the dominant forces shaping the NCC are large-scale, atmospheric heavy hitters. As the northeasterly trade winds blow across the globe, they set up the clockwise-rotating North Pacific Subtropical Gyre, a major feature covering about 20 million square kilometers of the Pacific Ocean. The equatorward-flowing part of the gyre is the California Current. It comprises an Eastern Boundary Upwelling Ecosystem, one of four such global systems that, while occupying only 1% of the global ocean, are responsible for a whopping 11% of its total primary productivity, and 17% of global fish catch.

Figure 1. Important features of the California Current System (Checkley and Barth, 2009).

At its core, this incredible ocean productivity is due to atmospheric pressure gradients. Every spring, an atmospheric system called the North Pacific High strengthens, loosening the hold of the stormy Aleutian Low. As a result, the winds begin to blow from the north, pushing the surface water in the NCC with them towards the equator.

This water is subject to the Coriolis effect – an inertial force that acts upon objects moving across a rotating frame of reference, and the same force that airplane pilots must account for in their flight trajectories. As friction transmits the stress of wind acting upon the ocean’s surface downward through the water column, the Coriolis effect deflects deeper layers of water successively further to the right, before the original wind stress finally peters out due to frictional losses.

This process creates an oceanographic feature called an Ekman spiral, and its net effect in the NCC is the offshore transport of surface water. Deep water flows up to replace it, bringing along nutrients that feed the photosynthesizers at the base of the food web. Upwelling ecosystems like the NCC tend to be dominated by food webs full of large organisms, in which energy flows from single-celled phytoplankton like diatoms, to grazers like copepods and krill, to predators like fish, seabirds, and our favorite, whales. These bountiful food webs keep us busy: GEMM Lab research has explored how upwelling dynamics impact gray whale prey off the Oregon coast, as well as parallel questions far from home about blue whale prey in New Zealand.

Figure 2. The Coriolis effect creates an oceanographic feature called an Ekman Spiral, resulting in water transport perpendicular to the wind direction (Source: NOAA).

Although the process of upwelling lies at the heart of the productive NCC ecosystem, it isn’t enough for it to simply happen – timing matters, too. The seasonality of ecological events, or phenology, can have dramatic consequences for the food web, and individual populations in it. When upwelling is initiated as normal by the “spring transition”, the delivery of freshly upwelled nutrients activates the food web, with reverberations all the way from phytoplankton to predators. When the spring transition is late, however, the surface ocean is warm, nutrients are depleted, primary productivity is low, and the life cycles and abundances of some species can change dramatically. In 2005, for example, the spring transition was delayed by a month, resulting in declines and spatial redistributions of the taxa typically found in the NCC, including hake, rockfish, albacore tuna, and squid. The Cassin’s auklet, which feeds on plankton, suffered its worst year on record, including reproductive failure that may have resulted from a lack of food.

Upwelling is alchemical in its power to transform, modulating physical and atmospheric processes and turning them into ecosystem gold – or trouble. As oceanographers and Oregonians alike wonder how climate change may reshape our coast, changes to upwelling will likely play a big role in determining the outcome. Some expect that upwelling-favorable winds will become more prevalent, potentially increasing primary productivity. Others suspect that the timing of upwelling will shift, and ecological mismatches like those that occurred in 2005 will be increasingly detrimental to the NCC ecosystem. Whatever the outcome, upwelling is inherent to the character of the Oregon coast, and will help shape its future.

Figure 3. The GEMM Lab is grateful that the biological productivity generated by upwelling draws humpback whales like this one to the Oregon coast! (photo: Dawn Barlow)

References

Chavez, Francisco & Messié, Monique. (2009). A comparison of Eastern Boundary Upwelling Ecosystems. Progress In Oceanography. 83. 80-96. 10.1016/j.pocean.2009.07.032.

Chavez, F P., and J R Toggweiler, 1995: Physical estimates of global new production: The upwelling contribution. In Dahlem Workshop on Upwelling in the Ocean: Modern Processes and Ancient Records, Chichester, UK, John Wiley & Sons, 313-320.

Checkley, David & Barth, John. (2009). Patterns and processes in the California Current System. Progress In Oceanography. 83. 49-64. 10.1016/j.pocean.2009.07.028.

El Niño de Navidad: What is atmospheric Santa Claus bringing to Oregon krill and whales?

By Rachel Kaplan, PhD student, Oregon State University College of Earth, Ocean, and Atmospheric Sciences and Department of Fisheries, Wildlife, and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab

Early June marked the onset of El Niño conditions in the Pacific Ocean , which have been strengthening through the fall and winter. For Oregonians, this climate event means unseasonably warm December days, less snow and overall precipitation (it’s sunny as I write this!), and the potential for increased wildfires and marine heatwaves next summer.

This phenomenon occurs about every two to seven years as part of the El Niño Southern Oscillation (ENSO), a cyclical rotation of atmospheric and oceanic conditions in the Pacific Ocean that is initiated by departures from and returns to “normal conditions” at the equator. Typically, the trade winds blow warm water west along the equator, and El Niño occurs when these winds weaken or reverse. As a result, the upwelling of cold water at the equator ceases, and warm water flows towards the west coast of the Americas, rather than its typical pathway towards Asia. When the trade winds resume their normal direction, usually after months or a year, the system returns to “normal” conditions – or, it can enter the cool La Niña part of the cycle, in which the trade winds are stronger than normal. “El Niño de Navidad” was named by South American fisherman in the 1600s because this event tends to peak in December – and El Niño is clearly going to be a guest for Christmas this year.

Figure 1. Maps of sea surface temperature anomalies show Pacific Ocean conditions during a strong La Niña (top) and El Niño (bottom). Source: NOAA climate.gov

These events at the equator trigger changes in global atmospheric circulation patterns, and they can shape weather around the world. Teleconnection, the coherence between meteorological and environmental phenomena occurring far apart, is to me one of the most incredible things about the natural world.  This coherence means that the biological community off the Oregon coast is strongly impacted by events initiated at the equator, with consequences that we don’t yet fully understand.

The effects of El Niño are diverse – floods in some places, droughts in others – and their onset can mean wildly different things for Oregon, Peru, Alaska, and beyond. As we tap our fingers waiting to be able to ski and snowboard in Oregon, what does our current El Niño event mean for the life in the waters off our coast?

Figure 2. Anomalous conditions at the equator qualified as an El Niño event in June 2023.

ENSO plays a big role in the variability in our local Northern California Current (NCC) system, and the outcomes of these events can differ based on the strength and how the signal propagates through the ocean and atmosphere (Checkley & Barth, 2009). Large-scale “coastal-trapped” waves flowing alongshore can bring the warm water signal of an El Niño to our ocean backyard in a matter of weeks. One of the first impacts is a deepening of the thermocline, the upper ocean’s steep gradient in temperature, which changes the cycling of important nutrients in the surface ocean. This can result in a decrease in upwelling and primary productivity that sends ramifications through the food web, including consequences for grazers and predators like zooplankton, marine mammals, and seabirds (Checkley & Barth, 2009).

In addition to these ecosystem effects that result from local changes, the ocean community can also receive new visitors from afar, and see others flee . For krill, the shrimp-like whale prey that I spend a lot of my time thinking about, community composition can change as subtropical species typically found off southern and Baja California are displaced by horizontal ocean flow, or as resident species head north (Lilly & Ohman, 2021).

Figure 3. This Euphausia gibboides krill is typically found in offshore subtropical habitats but moves north and inshore during El Niño events, and tends to persist awhile in these new environments, impacting the local zooplankton community. Source: Solvn Zankl

The two main krill species that occur in the NCC, Euphausia pacifica and Thysanoessa spinifera, favor the cool, coastal waters typical off the coast of Oregon. During El Niño events, E. pacifica tends to contract its distribution inshore in order to continue occupying these conditions, increasing its spatial overlap with T. spinifera (Lilly & Ohman, 2021). In addition, both tend to shift their populations north, toward cooler, upwelling waters (Lilly & Ohman, 2021).

These krill species are a favored prey of rorqual whales, and the coast of Oregon is an important foraging ground for humpback, blue, and fin whales. Predators tend to follow their prey, and shifting distributions of these krill species may cause whales to move, too. During the 2014-2015 “Blob” event in the Pacific Ocean, a marine heatwave was exacerbated by El Niño conditions. Humpback whales in central California shifted their distributions inshore in response to sparse offshore krill, increasing their overlap with fishing gear and leading to an increase in entanglement events (Santora et al., 2020). Further north, these conditions even led humpback whales to forage in the Columbia River!

Figure 4. In September 2015, El Niño conditions led humpback whales to follow their prey and forage in the Columbia River.

As El Niño events compound with the impacts of global climate change, we can expect these distributional shifts – and perhaps surprises – to continue. By the year 2100, the west coast habitat of both T. spinifera and E. pacifica will likely be constrained due to ocean warming – and when El Niños occur, this habitat will decrease even further (Lilly & Ohman, 2021). As a result, the abundances of both species are expected to decrease during El Niño events, beyond what is seen today (Lilly & Ohman, 2021). This decline in prey availability will likely present a problem for future foraging whales, which may already be facing increased environmental challenges.

Understanding connections is inherent to the field of ecology, and although these environmental dependencies are part of what makes life so vulnerable, they can also be a source of resilience. Although humans have known about ENSO for over 400 years, the complex interplay between nature, anthropogenic systems, and climate change means that we are still learning the full implications of these events. Just as waiting for Santa Claus always keeps kids guessing, the dynamic ocean keeps surprising us, too.

References

Checkley, D. M., & Barth, J. A. (2009). Patterns and processes in the California Current System. Progress in Oceanography, 83(1–4), 49–64. https://doi.org/10.1016/j.pocean.2009.07.028

Lilly, L. E., & Ohman, M. D. (2021). Euphausiid spatial displacements and habitat shifts in the southern California Current System in response to El Niño variability. Progress in Oceanography, 193, 102544. https://doi.org/10.1016/j.pocean.2021.102544

Santora, J. A., Mantua, N. J., Schroeder, I. D., Field, J. C., Hazen, E. L., Bograd, S. J., Sydeman, W. J., Wells, B. K., Calambokidis, J., Saez, L., Lawson, D., & Forney, K. A. (2020). Habitat compression and ecosystem shifts as potential links between marine heatwave and record whale entanglements. Nat Commun, 11(1), 536. https://doi.org/10.1038/s41467-019-14215-w

Krill Intentions: Bringing Lessons Home from a Winter of Fieldwork

By Rachel Kaplan, PhD student, Oregon State University College of Earth, Ocean, and Atmospheric Sciences and Department of Fisheries, Wildlife, and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab

Hello from Palmer Station, Antarctica! I’ve spent the last five months here in a kind of parallel universe to that of my normal life in Oregon. It’s spring here at the Western Antarctic Peninsula (WAP), and since May I’ve been part of a team studying Antarctic krill (Euphausia superba) – a big change from the Oregon species I typically study, and one that has already taught me so much.

I am here as part of a project titled “The Omnivore’s Dilemma: The effect of autumn diet on winter physiology and condition of juvenile Antarctic krill”. Through at-sea fieldwork and experiments in the lab, we have spent this field season investigating how climate-driven changes in diet impact juvenile and adult krill health during the long polar night. Winter is a crucial time for krill survival and recruitment, and an understudied season in this remote corner of the world.

Figure 1. Recently collected Antarctic krill (Euphausia superba) await identification and measuring.

Within this field season, we have been part of two great research cruises along the WAP, and spent the rest of the time at Palmer Station, running long-term experiments to learn how diet influences krill winter growth and development. The time has passed incredibly fast, and it’s hard to believe that we’ll be heading home in just a couple weeks.

There have been so many wonderful parts to our time here. While at sea, I was constantly aware that each new bay and fjord we sampled was one of the most beautiful places I would ever have the privilege to visit. I was also surprised and thrilled by the number of whales we saw – I recorded over one hundred sightings, including humpbacks, minke, and killer whales. As consumed as I was by looking for whales during the few hours of daylight, it was also rewarding to broaden my marine mammal focus and learn about another krill predator, the crabeater seal, from a great team researching their ecology and physiology.

In between our other work, I have been processing active acoustic (echosounder) data collected during a winter 2022 cruise that visited many of the same regions of the WAP. Antarctic krill have been much more thoroughly studied than the main krill species that occur off the coast of Oregon, Euphausia pacifica and Thysanoessa spinifera, and it has been amazing to draw upon this large body of literature. 

Figure 2. The active acoustic data I’m working with from the Western Antarctic Peninsula, pictured here, was collected along a wiggly cruise track in 2022, giving me the opportunity to learn how to process this type of survey data and appreciate the ways in which a ship’s movements translate to data analysis.

Working with a new flavor of echosounder data has presented me with puzzles that are teaching me to navigate different modes of data collection and their analytical implications, such as for the cruise track data above. I’ll never take data collected along a standardized grid for granted again!

I’ve also learned new techniques that I am excited to apply to my research in the Northern California Current (NCC) region. For example, there are two primary different ways of detecting krill swarms in echosounder data: by comparing the results of two different acoustic frequencies, and by training a computer algorithm to recognize swarms based on their dimensions and other characteristics. After trying a few different approaches with the Antarctic data this season, I developed a way to combine these techniques. In the resulting dataset, two different methods have confirmed that a given area represents krill, which gives me a lot of confidence in it. I’m looking forward to applying this technique to my NCC data, and using it to assess some of my next research questions.

Figure 3. A combination of krill detection techniques selected these long krill aggregations off the coast of the Western Antarctic Peninsula (WAP).

Throughout it all, the highlight of this season has been being part of an amazing field team. I’m here with Kim Bernard (as a co-advised student, I refer to Kim as my “krill advisor” and Leigh as my “whale advisor”), and undergraduate Abby Tomita, who just started her senior year at OSU remotely from Palmer. From nights full of net tows to busy days in the lab, we’ve become a well-oiled machine, and laughed a lot along the way. Working with the two of them makes me sure that we’ll be able to best any difficulties that come up.

Now, our next challenge is wrapping up our last labwork, packing up equipment and samples, and getting ready to say goodbye. Leaving this wild, remote place is always heartbreaking – you never really know if you’ll be back. But there’s a lot to look forward to as we journey north, too: I can’t wait to hug my family and friends, eat a salad, and drive out to Newport to see the GEMM Lab. I’m excited to head back to the world with everything I’ve learned here, and to keep working.

Figure 4. Kim (left), Abby (middle), and I (right) hike on the Marr Ice Piedmont during a gorgeous day off.

Exploring the Western Antarctic Peninsula  

By Abby Tomita, undergraduate student, OSU College of Earth, Ocean, and Atmospheric Sciences, research intern in the GEMM and Krill Seeker Labs

This February, during the winter term of my third year at Oregon State, I was presented with a once-in-a-lifetime opportunity. After spending the last year studying the zooplankton krill as part of Project OPAL, I was invited to spend the austral winter season doing research on Antarctic krill (Euphausia superba) under supervision of experts Dr. Kim Bernard and PhD student Rachel Kaplan. Additionally, we were lucky enough to participate in two research cruises along the Western Antarctic Peninsula (WAP). 

Figure 1. Sailing into the sunset on the RV Laurence M. Gould.

Unsurprisingly, it is no easy feat getting to the bottom of the world. After an incredibly thorough physical qualification process and two days of air travel from Portland, Oregon, we reached the lovely city of Punta Arenas, Chile. It was such a relief to arrive – but we were only halfway there. The next portion of our trip was the one that I was most anxious about, especially as someone who is prone to seasickness: crossing the Drake Passage. This stretch of the ocean, from the southernmost tip of South America to the Antarctic Peninsula, is notoriously treacherous as water in this area circulates the globe completely unobstructed by land masses. I soon learned the value of scopolamine patches and nausea bracelets, which helped me immensely through this five day journey. From Punta Arenas, we boarded the RV Laurence M. Gould, along with a seal research team from the University of North Carolina Wilmington. They were headed down south to look for crabeater seals to better understand not only their physiology, but also their role in the trophic ecology of the WAP. 

The Passage was rough, but not as terrible as I expected. The hype around it made me think I’d be faced with something as menacing as the giant wave from The Perfect Storm, and while the rocking and rolling of the ship was far from pleasant, my nausea aids, as well as the amazing people and vast selection of movies on board made it manageable. Despite being extremely nervous for the Passage, I was also very excited to celebrate my twenty-first birthday during it. It was a memorable, although untraditional birthday experience that was made all the more special by my friends on the ship who took the time to celebrate the day as best as we could. 

Figure 2. Taking in the sights of the Neumayer Channel with Kim!

The morning that we reached the Bransfield Strait was something truly unforgettable. Up until that point, I knew our destination was Antarctica, but I couldn’t really wrap my head around it because it was such a distant place and concept to me. I remember walking out onto the starboard side of the second level deck and seeing huge mountains out in the distance. For some reason, I had never considered how massively tall the mountains of the peninsula are, and just the fact that there were mountains down here at all. I joined the others at the bow, where we stood for hours in awe at the first land we had seen in days. Though many of the other scientists and crew members on board had been to this icy continent before, this was my first time, and I was in a state of disbelief. We’d finally made it and it sunk into me that I was in Antarctica, and that I would be here for the next five and half months.

After a day of hiding from strong winds in the Neumayer Channel, we were able to dock at Palmer Station (the smallest of the three US research bases in Antarctica) for our first port call, and seeing Palmer for the first time was just as exciting as seeing the continent. It looked so small at first, especially with the glacier and mountains looming behind it. Once the ship was tied up, orientation began. The station manager came onto the ship to give us an overview of what we could expect on station and the general Palmer etiquette. Next, we were given a tour of the facilities, from the lab spaces and aquarium room, up through the galley/dining area, past the hot tub and sauna, and into the lounge and bar in the GWR (Garage, Warehouse, and Recreation) building. I was surprised at how cozy the station was on the inside. In pictures, the buildings’ exteriors looked similar to the outside of a metal shipping container, but the inside was welcoming and warm. Those of us staying on station then sat through several hours of a more detailed orientation that somehow wore us out despite sitting in comfy recliner sofas the whole time. After sleeping on the rocking ship for about a week, I had some of the best sleep of my life that first night at Palmer Station.

Figure 3. Arriving at the Palmer Station pier in the first morning light.

Our first research cruise started a few days after arriving at Palmer, and just like that, we were off to explore the Southern Ocean. This leg of the trip took us south, down to Marguerite Bay and the region of Alexander Island, for ten days. The views were just spectacular everywhere we went, and it was so humbling to step out onto the deck to see gigantic mountains all around the ship. By day, us “krillers”, as our team is known, camped out on the bridge of the ship with the seal team, where we looked for sea ice floes with lounging crabeater seals. By night we conducted CTD casts, filtered water for chlorophyll, and deployed nets to catch our favorite tiny crustacean critters, along with any other zooplankton in our track. Unfortunately for both our group and the seal team, many areas that we visited were not frequented by krill or crabeater seals, though the seal team did successfully study and tag one seal over the course of the first cruise. 

Figure 4. Rachel (right) and I (left) filtering water for chlorophyll on the LMG. 

One of the highlights of this leg of the cruise was our Crossing Ceremony, as we’d crossed the Antarctic Circle (approximately 66.5ºS) shortly after leaving Palmer station. Myself and six others were crossing for the first time, so to earn our “Red Noses”, we had to pay tribute to King Neptune and his court. It would not be a Crossing Ceremony without at least some light pranking, so when they brought us out individually to the main deck, I knew something was coming our way.

Figure 5. Taking a celebratory picture with King Neptune’s court…with a surprise after.

The ten days flew by, and when we arrived back on station, we had less than a week to prepare for our next excursion on the LMG, which would be fifteen days. The time back at Palmer went quickly as we organized our lab space and entered data from the first cruise. The ship came back once more and we were off, this time heading north along the Peninsula to the Gerlache Strait. The sights were as breathtaking as ever, and I was excited to be back with my friends from the ship. 

Figure 6. Kim (left) and I (right) pour krill we caught into an XACTIC tank.

Our first day of transit was through the Lemaire Channel, one of the most stunning areas that we passed through (check out the photo gallery at the end of this post!). We spent the majority of the day on the bow and the deck of the bridge taking in the beautiful towering mountains on either side of the narrow channel and watching for penguins and humpbacks, of which there were many. This voyage segued into an extremely productive night of science for us where we caught thousands of krill that we were able to keep live in tanks on the ship, in preparation for later use for our experiments on station. Our first productive night of science was auspicious for the rest of the cruise as we caught and processed thousands more krill, and the seal team had a much more fruitful experience finding crabeater seals (they found/worked on 8 seals and named them all after fruits!). The highlight of this second cruise for me was getting to accompany the seal team onto an ice floe in the Lemaire Channel to assist them in their work on the crabeater, a female juvenile who they named Mango!

Figure 7. Watching Mango’s nose to calculate and record her breaths per minute (US NMSF Permit #25770).

Returning to Palmer for the final time on the LMG was just as exciting as arriving the first time, especially with the knowledge that we’d have one last night of celebration with our friends from the ship at the Cross Town Dinner – a night to celebrate the solstice with both the Palmer crew and LMG crew. Although the dinner and subsequent party were a blast, I felt a lingering sadness knowing that the majority of the people I spent almost two months with would be heading north, back to their respective homes while Kim, Rachel, and I stayed at Palmer for the next few months. The next day, after saying our goodbyes, the three of us stood on the Palmer pier with tears streaming down our faces, waving frantically at the ship to our friends on the deck. In spite of my sadness, I knew that the coming months would be a thrilling series of new experiences in one of the most magical and special places that I have ever had the pleasure of being in. 

Figure 8. The LMG departs Palmer Station for the last time this winter! 

Navigating the Research Rollercoaster

By Amanda Rose Kent, College of Earth Ocean and Atmospheric Sciences, OSU, GEMM Lab/Krill Seeker undergraduate intern

If you asked me five years ago where I’d thought I’d be today, the answer I would give would not reflect where I am now. Back then, I was a customer service representative for a hazardous waste company, and I believed that going to university and participating in research was a straightforward experience. I learned soon after I left that career and began my journey at OSU in 2020 that I wasn’t even remotely aware of the process. I knew that as part of my oceanography degree I would need to become involved in some form of research, but I had no idea where to start.

I started looking through the Oregon State website and I eventually found an outdated flier from 2018 that advertised a lab that studied plankton in Antarctica, and that was when I first reached out to Dr. Kim Bernard. My journey took off from there. As an undergraduate researcher in the URSA Engage program working with Kim and one of her graduate students, Rachel, I conducted a literature review on the ecosystem services provided by two species of krill off the coast of Oregon, including their value to baleen whales. After learning all I could from the literature about krill and how important they were to the ocean, I knew that there was so much more to learn and that this was the topic I wanted to continue to pursue. After I completed the URSA program, I remained a member of Kim’s zooplankton ecology lab.

While continuing to work with Rachel, I was given the opportunity to join the GEMM Lab’s Project HALO for a daylong cruise conducting a whale survey along the Newport Hydrographic Line. I was initially brought on to learn how to use the echosounder to collect krill data but unfortunately, the device had technical difficulties and Rachel and I were no longer needed. We decided to go on the cruise anyway, and I was able to instead learn how to survey for marine mammals (it’s not as easy as it may seem, but still very fun!).

Figure 1. Enjoying the point of view from the crow’s nest on the R/V Pacific Storm, but also very cold.

Soon, another opportunity arose to apply for a brand-new program called ARC-Learn. This two-year research program focuses on studying the Arctic using publicly available data, and with the support of my mentors, I applied and was accepted. Initially I found that there were no mentors within the program that studied krill, so I found myself becoming immersed in a new topic: harmful algal blooms (HABs). Determined to incorporate krill into this research, I started looking through the literature trying to develop my hypothesis that HABs affected zooplankton in some way. There was evidence to potentially support my hypothesis, but I ended up encountering numerous data gaps in the region I was studying. After months of roadblocks, I eventually started feeling defeated and regretted applying for the program. Rachel was quick to remind me that all experiences are valuable experiences, and that I was still gaining new skills I could use in graduate school or my career.

As my undergraduate degree progressed, I continued supporting Rachel in her graduate research, spending some time during the summer processing krill samples by sorting, sexing, and drying them to crush them into pellets. Our goal was to process them in an instrument called a bomb calorimeter, which is used to quantify the caloric content of prey species and help us better understand the energy flux required for animals higher up the food chain (like whales) and the amount they need to eat. I was only able to do this for a few weeks before heading out on the experience of a lifetime, spending three weeks on a ship traveling around the Bering, Chukchi, and Beaufort Seas with one of my ARC-Learn mentors. It was a great opportunity for me to see the toxic phytoplankton (which can form HABs) I had been studying and learn about methods of sample collection and processing. If I could go back and do it again, I’d go in a heartbeat.

Figure 2. Pulling out all of the animal biomass out of the Arctic sediment.

At the beginning of my bachelor’s degree, I had expected to just work with Kim and conduct research within her lab. Instead, I have had opportunities I would never have expected five years ago. I have learned a vast amount from my graduate mentor, Rachel, which has helped influence my trajectory in my degree. I have had the privilege to not only meet giants in the field I’m interested in, but also work with them and learn from them, and to spend three weeks in the Arctic Ocean.  The experiences I have had throughout this roller-coaster helped me develop a project idea with new mentors that I eventually hope to pursue in my master’s degree. I wasn’t prepared for the number of adjustments I would make to find new experiences and start new projects, but all the experiences I had were necessary to learn about what I was interested in and what I wanted to pursue. Looking back on it all today, I have zero regrets.

Figure 3. A picture of the Norseman II, the ship I was on in the Arctic, taken by the Japanese ship JAMSTEC on a short rendezvous between the Chukchi and Beaufort Seas.

Migrating south to another foraging ground

By Rachel Kaplan, PhD student, OSU College of Earth, Ocean and Atmospheric Sciences and Department of Fisheries, Wildlife, & Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab 

Krill, a shrimplike crustacean found across our oceans, embodies the term “small but mighty”. Though individuals tend to be small, sometimes weighing in at less than a gram, the numerous species of krill have a global distribution and are estimated to collectively outweigh the entire human population. Much of my graduate research focuses on relationships between foraging whales and krill (Euphausia pacifica and Thysanoessa spinifera) in the Northern California Current (NCC) region. This work hinges on themes that are universal across environments: just as krill are ubiquitous across the global ocean, questions of prey quality, distribution, and ecological relationships with predators are universal.

Next week, I’m headed south to consider these questions in a very different foraging environment: the Western Antarctic Peninsula (WAP). One benefit of being a co-advised student is the incredible opportunity to be exposed to diverse projects and types of research. My graduate co-advisor, Kim Bernard, has studied krill in the WAP region for over a decade, and she is currently leading research into the implications of the shifting polar food web for Antarctic krill (Euphasia superba). Through a series of laboratory experiments and fieldwork, the project, titled “The Omnivore’s Dilemma: The effect of autumn diet on winter physiology and condition of juvenile Antarctic krill”,  investigates the impact of climate-driven changes in diet on the health of juvenile krill in autumn and winter, a key time for their survival and recruitment. Winter is a poorly studied season in Antarctica, and this project has already shed light on the physiology, respiration, and growth potential of juvenile krill (Bernard et al., 2022).

 Figure 1: Antarctic krill are much bigger than those found in the NCC region – they can be as long as your thumb! (Source: Australian Antarctic Program)

Just as in the NCC region, krill are an essential link in Southern Ocean food webs, where they transfer energy from their microscopic prey to the higher trophic levels that eat them, including several species of fish, seals, penguins, and whales (Bernard & Steinberg, 2013; Cavan et al., 2019; Ducklow et al., 2013). These predators depend upon this high-quality prey to fuel their seasonal migrations and to build the energy reserves they need to survive the frigid Antarctic winter (Cade et al., 2022; Schaafsma et al., 2018). But, the quality of krill depends upon the food that it can consume itself, and climate change may alter their diet.

There’s a lot to love about krill, but my fascination with them is directly tied to their value as a food source for predators. I want to know how the caloric content of individuals and the aggregations they form changes spatially along the WAP, and how this might shift under climate-forced food web changes. This work will clarify the climate-driven variability in the quality of krill as prey, and the implications this might have for top predators in the region.

Figure 2: The upcoming field season will involve sampling krill along a latitudinal gradient in the WAP region, spanning approximately from the Gerlache Strait in the north to Marguerite Bay in the south (Bernard et al., 2022).

In order to investigate these questions, I’ll be spending the next six months based out of Palmer Station, the smallest of the United States’ research bases in Antarctica, along with Kim and our undergraduate intern Abby. During this upcoming field season, we’ll spend about a month at sea collecting krill samples and active acoustic data using an echosounder, and the rest of the time conducting experiments and sampling in the nearshore. Over the last year, Abby has worked with me to quantify krill caloric content in the NCC, as well as processing samples collected in Antarctica last year. I’m so impressed by everything she’s accomplished, and excited to see her take in this environment, learn a fresh set of experimental and field sampling approaches, and be inspired to ask new questions.

Figure 3: Abby preparing NCC krill samples for caloric analysis (Kim Kenny/OSU CEOAS).

For me, heading south will be a bit like coming home. After graduating from college, I spent about nine months living at Palmer Station and working on the microbial ecology component of the long-term ecological research station there. The experience of being immersed in the WAP environment was foundational to my curiosity about ocean ecology and the impacts of climate change. It is also where I met Kim! All in all, this environment fueled my desire to study krill with Kim and spatial ecology with Leigh, and set me on the course I’m on today.

It also feels meaningful to return here again at this point in my educational journey. With new knowledge and questions I have formed while working in the NCC, I am now excited to apply this knowledge and consider similar questions in the WAP. Abby and I will write blogs through the season and post them here, so stay tuned for news from down south!

Figure 4: Kim and I (the two farthest right in the front row) prepare for a group costumed polar plunge in 2015. Will we do it again? We’ll keep you posted!

References

Bernard, K. S., & Steinberg, D. K. (2013). Krill biomass and aggregation structure in relation to tidal cycle in a penguin foraging region off the Western Antarctic Peninsula. ICES Journal of Marine Science, 70(4), 834–849. https://doi.org/10.1093/icesjms/fst088

Bernard, K. S., Steinke, K. B., & Fontana, J. M. (2022). Winter condition, physiology, and growth potential of juvenile Antarctic krill. Frontiers in Marine Science, 9, 990853. https://doi.org/10.3389/fmars.2022.990853

Cade, D. E., Kahane-Rapport, S. R., Wallis, B., Goldbogen, J. A., & Friedlaender, A. S. (2022). Evidence for Size-Selective Predation by Antarctic Humpback Whales. Frontiers in Marine Science, 9, 747788. https://doi.org/10.3389/fmars.2022.747788

Cavan, E. L., Belcher, A., Atkinson, A., Hill, S. L., Kawaguchi, S., McCormack, S., Meyer, B., Nicol, S., Ratnarajah, L., Schmidt, K., Steinberg, D. K., Tarling, G. A., & Boyd, P. W. (2019). The importance of Antarctic krill in biogeochemical cycles. Nat Commun, 10(1), 4742. https://doi.org/10.1038/s41467-019-12668-7

Ducklow, H., Fraser, W., Meredith, M., Stammerjohn, S., Doney, S., Martinson, D., Sailley, S., Schofield, O., Steinberg, D., Venables, H., & Amsler, C. (2013). West Antarctic Peninsula: An Ice-Dependent Coastal Marine Ecosystem in Transition. Oceanography, 26(3), 190–203. https://doi.org/10.5670/oceanog.2013.62

Schaafsma, F. L., Cherel, Y., Flores, H., van Franeker, J. A., Lea, M.-A., Raymond, B., & van de Putte, A. P. (2018). Review: The energetic value of zooplankton and nekton species of the Southern Ocean. Marine Biology, 165(8), 129. https://doi.org/10.1007/s00227-018-3386-z

SST, EKE, SSH: Wading Through the Alphabet Soup of Oceanographic Parameters related to Deep-Dwelling Odontocetes

By: Marissa Garcia, PhD Student, Cornell University, Department of Natural Resources and the Environment, K. Lisa Yang Center for Conservation Bioacoustics

Predator-Prey Inference: A Tale as Old as Time

It’s a tale as old as time: where there’s prey, there’ll be predators.

As apex predators, cetaceans act as top-down regulators of ecosystem function. While baleen whales act as “ecosystem engineers,” facilitating nutrient cycling in the ocean (Roman et al., 2014), toothed whales, or “odontocetes,” can impart keystone-level effects — that is, they disproportionately control the marine community’s food-web structure (Valls, Coll, & Christensen, 2015). The menus of prey vary widely by species — ranging from mircronekton to fish to squid – and by extension, vary widely across trophic levels.

So, it naturally follows the old adage: where there’s an abundance of prey, there’ll be an abundance of cetaceans. Yet, creating models that accurately depict this predator-prey relationship is, perhaps unsurprisingly, not as straightforward.

Detecting the ‘Predator’ Half of the Equation

Scientists have successfully documented cetacean presence drawing upon a myriad of methods, each bearing its unique advantages and limitations.

Visual surveys — spanning viewpoints from land, boats, and air — can attain precise spatial data and species ID. However, this data can be constrained by “availability bias” — that is, scientists can only observe cetaceans visible at the surface, not those obscured by the ocean’s depths. Species that spend less time near the surface are more likely to elude the observer’s line of sight, thereby being missed in the data. Consequently, visual surveys have historically undersampled deep-diving species. For instance, since its discovery by western science in 1945, the Hubb’s beaked whale (Mesoplodon carlshubbi) has only been observed alive twice by OSU MMI’s very own Bob Pitman, once in 1994 and another time in 2021.

Scientists have also been increasingly conducting acoustic surveys to document cetacean presence. Acoustic recorders can “hear” each cetacean species at different ranges. Baleen whales, which bellow low-frequency calls, can be heard as far as across ocean basins (Munk et al., 1994). Toothed whales whistle, echolocate, and buzz at frequencies so high they’re considered ultrasonic. But it comes at a trade-off: high-frequency sounds have shorter wavelengths, meaning they are heard across smaller ranges. This high variability, which scientists refer to as “detection range,” translates to not always knowing where the vocalizing cetacean that was recorded is: as such, acoustic data can lack the high-resolution spatial precision often achieved by visual surveys. Nevertheless, acoustic data triumphs in temporal extent, sometimes managing to record continuously at six months at a time. Additionally, animals can elude visual detection in poor weather conditions or if they have a cryptic surface expression, but detected in acoustic surveys (e.g., North Atlantic right whales (Eubalaena glacialis) (Ganley, Brault, & Mayo, 2019; Clark et. al, 2010). Thus, acoustic surveys may be especially optimal for recording elusive deep-dwellers that occupy the often rough Oregon waters, such as beaked whales, the focus of my research in collaboration with the GEMM Lab.

Figure 1: HALO Project researchers Marissa Garcia (left; Yang Center via Cornell) and Imogen Lucciano (right; OSU MMI) among three Rockhopper acoustic recording units, ahead of deployment off the Oregon coast. Credit: Marissa Garcia.

Detecting the ‘Prey’ Half of the Equation

Prey can be measured by numerous methods. Most directly, prey can be measured “in-situ” — that is, prey is collected directly from the site where the cetaceans are detected or observed. A 2020 study combined fish trawls with a towed hydrophone array to identify which fish species odontocetes along the continental shelf of West Ireland (e.g., pilot whales, sperm whales, and Sowerby’s beaked whales) were feasting; the results found that odontocetes primarily fed upon mesopelagic fish and cephalopods (Breen et al., 2020). While trawls can glean species ID of prey, associating this prey data with depth and biomass can prove challenging.

Alternatively, prey can be detected via active acoustics. Echosounders release an acoustic signal that descends through the water column and then echoes back once it hits a sound-scattering organism. Beaked whales forage within deep scattering layers typically composed of myctophid fish and squid, both of which can echo back echosounder pings (Hazen et al., 2011). Thus, echosounder data can map prey density through the water column. When mapping prey density of beaked whales, Hazen et al. 2011 found a strong positive correlation among prey density, ocean vertical structure, and clicks primarily produced while foraging – suggesting beaked whales forage at depth when encountering large, multi-species aggregations of prey.

Figure 2: An example of prey mapping via a Simrad EK60 120 kHz split-beam echosounder. Credit: Rachel Kaplan (OSU MMI) via the HALO Project.

Most relevant to the HALO Project, prey is measured using proximate indices, which are more easily quantifiable metrics of ocean conditions, such as collected from ships via CTD casts or via satellite imagery, that are indirectly related to prey abundance. CTD data can provide information related to the water column structure, including depth and strength of the thermocline, depth of the mixed layer, depth of the euphotic zone, and total chlorophyll concentration in the euphotic zone (Redfern et al. 2006). Satellite imagery can characterize the dynamic patterns of the surface later, including sea surface temperature (SST), salinity, surface chlorophyll a, sea surface height (SSH), and sea surface currents (Virgili et al., 2022; Redfern et al., 2006). Ocean model data products can, such as the Regional Ocean Modeling System (ROMS) which models how an oceanic region of interest responds to physical processes, can provide water column variables related to eddy kinetic energy (EKE) and average temperature gradients (Virgili et al., 2022). In the case of my research with the HALO Project, we will be using oceanographic data collected through the Ocean Observatories Initiative to inform odontocete species distribution models.

Connecting the Dots: Linking Deep-Dwelling Top Predators and Prey

While scientists have made significant advances with collecting both cetacean and prey data, connecting the dots between the ecology of deep-dwelling odontocetes and the oceanographic parameters indicative of their prey still remains a challenge.

In the absence of in situ sampling, species distribution models of marine top predators often derive proxies for “prey data” from static bathymetric and dynamic surface water variables (Virgili et al., 2022). However, surface variables may be irrelevant to toothed whale prey inhabiting great depths (Virgili et al., 2022). Within the HALO Project, the deepest Rockhopper acoustic recording unit is recording odontocetes at nearly 3,000 m below the surface, putting into question the relevance of oceanographic parameters collected at the surface.

Figure 3: Schematic depicting the variation among different zones in the water column. Conditions at the surface may not represent conditions at depth. Credit: Barbara Ambrose, NOAA via NOAA Ocean Explorer.

In my research, I am setting out to estimate which oceanographic variables are optimal for explaining deep-dwelling odontocete presence. A 2022 study using visual survey data found that surface, subsurface, and static variables best explained beaked whale presence, whereas only surface and deep-water variables – not static – best explained sperm whale presence (Virgili et al., 2022). These results are associated with each species’ distinct foraging ecologies; beaked whales may truly only rely on organisms that live near the seabed, whereas sperm whales also feast upon meso-to-bathypelagic organisms, so they may be more sensitive to changes in water column conditions (Virgili et al., 2022). This study expanded the narrative: deep-water variables can also be key to predicting deep-dwelling odontocete presence. The oceanographic variables must be tailored to the ecology of each species of interest.

In the months ahead, I seek to build on this study by investigating which parameters best predict odontocete presence using an acoustic approach instead — I am looking forward to the results to come!

References

Breen, P., Pirotta, E., Allcock, L., Bennison, A., Boisseau, O., Bouch, P., Hearty, A., Jessopp, M., Kavanagh, A., Taite, M., & Rogan, E. (2020). Insights into the habitat of deep diving odontocetes around a canyon system in the northeast Atlantic ocean from a short multidisciplinary survey. Deep-Sea Research. Part I, Oceanographic Research Papers, 159, 103236. https://doi.org/10.1016/j.dsr.2020.103236

Clark, C.W., Brown, M.W., & Corkeron, P. (2010). Visual and acoustic surveys

for North Atlantic right whales, Eubalaena glacialis, in Cape Cod Bay, Massachusetts, 2001–2005: Management implications. Marine Mammal Science, 26(4), 837-854.

Ganley, L.C., Brault, S., & Mayo, C.A. (2019). What we see is not what there is: Estimating North Atlantic right whale Eubalaena glacialis local abundance. Endangered Species Research, 38, 101-113.

Hazen, E. L., Nowacek, D. P., St Laurent, L., Halpin, P. N., & Moretti, D. J. (2011). The relationship among oceanography, prey fields, and beaked whale foraging habitat in the Tongue of the Ocean. PloS One, 6(4), e19269–e19269.

Munk, W. H., Spindel, R. C., Baggeroer, A., & Birdsall, T. G. (1994). The Heard Island Feasibility Test. The Journal of the Acoustical Society of America, 96(4), 2330–2342. https://doi.org/10.1121/1.410105

Redfern, J. V., Ferguson, M. C., Becker, E. A., Hyrenbach, K. D., Good, C., Barlow, J., Kaschner, K., Baumgartner, M. F., Forney, K. A., Ballance, L. T., Fauchald, P., Halpin, P., Hamazaki, T., Pershing, A. J., Qian, S. S., Read, A., Reilly, S. B., Torres, L., & Werner, F. (2006). Techniques for cetacean–habitat modeling. Marine Ecology. Progress Series (Halstenbek), 310, 271–295.

Roman, J., Estes, J. A., Morissette, L., Smith, C., Costa, D., McCarthy, J., Nation, J., Nicol, S., Pershing, A., & Smetacek, V. (2014). Whales as marine ecosystem engineers. Frontiers in Ecology and the Environment, 12(7), 377–385.

Valls, A., Coll, M., & Christensen, V. (2015). Keystone species: toward an operational concept for marine biodiversity conservation. Ecological Monographs, 85(1), 29–47.

Virgili, A., Teillard, V., Dorémus, G., Dunn, T. E., Laran, S., Lewis, M., Louzao, M., Martínez-Cedeira, J., Pettex, E., Ruiz, L., Saavedra, C., Santos, M. B., Van Canneyt, O., Vázquez Bonales, J. A., & Ridoux, V. (2022). Deep ocean drivers better explain habitat preferences of sperm whales Physeter macrocephalus than beaked whales in the Bay of Biscay. Scientific Reports, 12(1), 9620–9620.

Learning by teaching

By: Kate Colson, MSc Student, University of British Columbia, Institute for the Oceans and Fisheries, Marine Mammal Research Unit

One of the most frequent questions graduate students get asked (besides when you are going to graduate) is what their plans are after university. For me, the answer has always adamantly been continuing to do research, most likely as a government researcher because I don’t want teaching commitments to take away from my ability to conduct research.

However, one of the most fulfilling parts of my degree at University of British Columbia has actually been teaching four terms of a 100-level undergraduate science course focused on developing first-year students’ critical thinking, data interpretation, and science communication skills. My role in the course has been facilitating active learning activities that exercise these skills and reviewing material the students go over in their pre-class work. Through this course, I have experienced the teaching styles of six different professors and practiced my own teaching. As with any skill, there is always room for improvement, so when I had a chance to read a book titled How Learning Works: Seven Research-Based Principles for Smart Teaching (Ambrose et al. 2010), I took it as an opportunity to further refine my teaching and explore why some practices are more effective than others.

In the book, Ambrose et al. present principles of learning, the research surrounding these principles and examples for incorporating them into a university level course. Some of the principles gave me ideas for strategies to incorporate into my teaching to benefit my students. These described how prior knowledge impacts student learning and how to use goal-oriented practice and give feedback relative to target criteria that the students can apply to the next practice task. For example, I learned to be more conscious about how I explain and clarify course material to make connections with what the students have learned previously, so they can draw on that prior knowledge. Other principles presented by Ambrose et al. were more complex and offered a chance for greater reflection.

Beyond presenting strategies for improving teaching, the book also presented research that supported what I had learned firsthand through teaching. These principles related to the factors that motivate students to learn and why the course climate matters for learning. I have seen how student motivation is impacted by the classroom climate and culture put forth by the teaching team. Perhaps the most frustrating experiences I have had teaching were when one member of the teaching team does not see the importance of fostering a supportive course environment.

For this reason, my favorite assignments have been the Thrive Contract and the Group Contract. Each term, the Thrive Contract is the first major class activity, and the Group Contract is the first group assignment. These assignments serve as a means for everyone to co-create guidelines and expectations and establish a positive classroom culture for the rest of the term. After an exceptionally poor classroom experience my first time teaching, I have highlighted the importance of the Thrive Contract in all subsequent terms. Now, I realize the significance I lent this assignment is supported by the research on the importance for a supportive environment to maximize student motivation and encourage classroom engagement (Figure 1).

Another powerful lesson I have learned through teaching is the importance of clarifying the purpose of an activity to the students. Highlighting a task’s objective is also supported by research to ensure that students ascribe value to the assigned work, increasing their motivation (Figure 1).  In my teaching, I have noticed a trend of lower student participation and poorer performance on assignments when a professor does not emphasize the importance of the task. Reviewing the research that shows the value of a supportive course climate has further strengthened my belief in the importance of ensuring that students understand why their teaching team assigns each activity.

Figure 1. How environment, student efficacy, and value interact to impact motivation. The above figure shows that motivation is optimized when students see the value in a goal, believe they have the skills to achieve the goal, and are undertaking the goal in a supportive class environment (the bright blue box in the bottom right corner). If this situation were to occur in an unsupportive class environment, defiant behaviour (e.g. “I’ll prove you wrong” attitude) is likely to occur in response to the lack of support, as the student sees the value in the goal and believes in their ability to achieve the goal. Rejecting behaviour (e.g., disengagement) occurs when the student does not associate value to a task and does not believe in their ability to complete the goals regardless of the environment.  Evading behaviour (e.g., lack of attention or minimal effort) results when students are confident in their ability to complete a task, but do not see the goal as meaningful in both supportive and unsupportive environment. When a student sees the importance of the goal but are not confident in their ability to complete it, they become hopeless (e.g., have no expectation of success and act helpless) when in an unsupportive environment and fragile (e.g., feign understanding, deny difficulty, or make excuses for poor performance) in a supportive environment.  Diagram adapted from Ambrose et al. (2010) Figure 3.2 incorporating the works of Hansen (1989) & Ford (1992).

Potentially my favorite part about the structure of Ambrose’s book was that it offered me a chance to reflect not only on teaching, but also on my own learning and cognitive growth since I started my master’s degree. Graduate students are often in a unique position in which we are both students and teachers depending on the context of our surroundings. The ability to zoom out and realize how far I have come in not only teaching others, but also in teaching myself, has been humbling. My reflection on my own learning and growth has been driven by learning about how organizing knowledge affects learning, how mastery is developed and how students become self-directed learners.

One of the main differences between novices and experts in how they organize their knowledge is the depth of that knowledge and the connections made between different pieces of information. Research has shown that experts hold more connections between concepts, which allows for faster and easier retrieval of information that translates into ease in applying skills to different tasks (Bradshaw & Anderson, 1982; Reder & Anderson, 1980; Smith, Adams, & Schorr, 1978). Currently in my degree, I am experiencing this ease when it comes to coding my analysis and connecting my research to the broader implications for the field. By making these deeper connections across various contexts, I am building a more complex knowledge structure, thus progressing towards holding a more expert organization of knowledge.

In the stages of mastery concept proposed by Sprague and Stewart (2000), learners progress from unconscious incompetence where the student doesn’t know what they don’t know, to conscious incompetence where they have become aware of what they need to know (Figure 2). This was where I was when I started my master’s — I knew what objectives I wanted to achieve with my research, but I needed to learn the skills necessary for me to be able to collect the data and analyze it to answer my research questions. The next stage of mastery is conscious competence, in which the ability of the learner to function in their domain has greatly increased, but practicing the necessary skills still requires deliberate thinking and conscious actions (Figure 2). This is the level I feel I have progressed to — I am much more comfortable performing the necessary tasks related to my research and talking about how my work fills existing knowledge gaps in the field. However, it still helps to talk out my proposed plans with true masters in the field. The final stage of mastery, unconscious competence, is where the learner has reached a point where they can practice the skills of their field automatically and instinctively such that they are no longer aware of how they enact their knowledge (Figure 2).

Figure 2. Stages of mastery showing how the learner consciousness waxes and then wanes as competence is developed. Unconscious states refer to those where the learner is not aware of what they are doing or what they know, whereas conscious states have awareness of thoughts and actions. Competence refers to the ability of the learner to perform tasks specific to the field they are trying to master. Diagram adapted from Ambrose et al. (2010) Figure 4.2 incorporating the works of Sprague & Stewart (2000).

In line with my progression to higher levels of mastery has come the development of metacognitive skills that have helped me become a better self-directed learner. Metacognition is the process of learning how to learn, requiring the learner to monitor and control their learning through various processes (Figure 3). The most exciting part of my metacognitive growth I have noticed is the greater independence I have in my learning. I am much better at assessing what is needed to complete specific tasks and planning my particular approach to successfully achieve that goal (e.g., the construction of a Hidden Markov model from my last blog). By becoming more aware of my own strengths and weaknesses as a learner, I am better able to prepare and give myself the support needed for completing certain tasks (e.g., reaching out to experts to help with my model construction as I knew this was an area of weakness for me). By becoming more aware of how I am monitoring and controlling my learning, I know I am setting myself up for success as a lifelong learner.

Figure 3. Metacognition requires learner to monitor and control their learning through various processes. These processes involve the learner assessing the necessary skills needed for a task, evaluating their strengths and weaknesses with regards to the assigned task, and planning a way to approach the task. Once a plan has been made, the learner then must apply the strategies involved from the plan and monitor how those strategies are working to accomplish the assigned task. The learner must then be able to decide if the planned approach and applied strategies are effectively accomplishing the assigned task and adjust as needed with a re-assessment of the task that begins the processing cycle over again. Underlying each of these metacognitive processes are the learner’s belief in their own abilities and their perceptions of their intelligence. For example, students who believe their intelligence cannot be improved and do not have a strong sense of efficacy will be less likely to expend effort in metacognitive processes as they believe the extra effort will not influence the results. This contrasts with students who believe their intelligence will increase with skills development and have a strong belief in their abilities, as these learners will see the value in putting in the effort of trying multiple plans and adjusting strategies.  Diagram adapted from Ambrose et al. (2010) Figure 7.1 incorporating the cycle of adaptive learning proposed by Zimmerman (2001).

References:

Ambrose, S. A., Bridges, M. W., DiPietro, M., Lovett, M. C., & Norman, M. K. (2010). How learning works: Seven research-based principles for smart teaching (1st ed.). San Francisco, CA: Jossey-Bass. 

Bradshaw, G. L., & Anderson, J. R. (1982). Elaborative encoding as an explanation of levels of processing. Journal of Verbal Learning and Verbal behaviours, 21,165-174.

Ford, M. E. (1992). Motivating humans: Goals, emotions and personal agency beliefs. Newbury Park, CA: Sage Publications, Inc.

Hansen, D. (1989). Lesson evading and dissembling: Ego strategies in the classroom. American Journal of Education, 97, 184-208.

Reder, L. M., & Anderson, J. R. (1980). A partial resolution of the paradox of interference: The role of integrating knowledge.  Cognitive Psychology, 12,  447-472.

Smith, E. E., Adams, N., & Schorr, D. (1978). Fact retrieval and the paradox of interference. Cognitive Psychology, 10, 438-464.

Sprague, J., & Stewart, D. (2000). The speaker’s handbook. Fort Worth, TX: Harcourt College Publishers.

Zimmerman, B. J. (2001). Theories of self-regulated learning and academic achievement: An overview and analysis. In B. J. Zimmerman & D. H. Schunk (Eds.), Self-regulated learning and academic achievement (2nd ed., pp. 1-38). Hillsdale, NJ: Erlbaum.