Tag Archives: marine ecosystems

Is Climate Change Making Gray Whales Picky Eaters?

The Oregon Coast is known for its ruggedness and harsh weather, but also offers a prime opportunity to spot gray whales on their migratory paths. These majestic marine mammals undertake one of the largest migrations of any animal, traveling from the Arctic to Baja California to breed before heading back north along this “whale super-highway.” Despite having the mechanisms to feed in the water column, these benthic specialists prefer bottom feeding, scooping up sand from the seafloor and filtering out invertebrate prey through their baleen, likely targeting locations of high caloric content. However, along the coast of the Pacific Northwest, a behavior known as ‘prey switching’ has been observed, where gray whales feed in the water column instead of their preferred benthic prey, amphipods. Our upcoming guest, Taylor Azizeh, a first-year Ph.D. student at the Marine Mammal Institute, explores what may be driving this prey switching behavior.

Polar regions are among the top locations to be impacted by climate change, which Taylor suspects may be responsible for grey whales switching from benthic to pelagic prey. Changes in bottom water temperature and sediment grain size may result in habitats less favorable for amphipods, leading whales to seek food elsewhere. In response to warming, the distribution of other predators may shift to where they compete for the same food source, or the reduced sea ice cover could result in more productive pelagic waters. How do gray whales, these benthic specialists, adapt to changing food availability?

Gray whale populations often experience boom and bust cycles or unknown mortality events, with the most recent one currently underway. Taylor’s research on the foraging plasticity of gray whales is not only timely, but also employs a holistic approach using a combination of methods to assess the big picture. She plans to use stable isotopes to provide information on what whales are feeding on, but only when combined with GPS tags tracking movement and drone photogrammetry measuring body conditions can one understand where and why. Taylor plans to utilize this combination to ask big picture questions such as whether they’re feeding in areas of high biomass, if they return to those same areas, and how much adaptability can individual gray whales display?

At its core, Taylor’s research delves into the adaptability of gray whales. Gray whales have survived the ice ages, proving their ability to deal with harsh conditions, and Taylor hypothesizes they may be more flexible than we currently understand.

To learn more about Taylor’s passion for these charismatic animals of ecological, social, and cultural importance, the adventure which led here to grad school—from Costa Rica to Ecuador, Denmark, and London—tune in to KBVR 88.7 FM this Sunday, Nov. 3. You can listen to the episode anywhere you listen to your podcasts, including on KBVR, Spotify, Apple, or anywhere else!

Crabby and Stressed Out: Ocean Acidification and the Dungeness Crab

One of the many consequences associated with climate change is ocean acidification. This process occurs when high atmospheric carbon dioxide dissolves into the ocean lowering ocean pH. Concern about ocean acidification has increased recently with the majority of scientific publications about ocean acidification being released in the last 5 years. Despite this uptick in attention, much is still unknown about the effects of ocean acidification on marine organisms.

Close-up of a Dungeness crab megalopae

Our guest this week, Hannah Gossner, a second year Master’s student in the Marine Resource Management Program, is investigating the physiological effects of ocean acidification on Dungeness crab (Metacarcinus magister) with the help of advisor Francis Chan. Most folks in Oregon recognize the Dungeness crab as a critter than ends up on their plate. Dungeness crab harvest is a multimillion dollar industry because of its culinary use, but Dungeness crab also play an important role in the ocean ecosystem. Due to their prevalence and life cycle, they are important both as scavengers and as a food source to other animals.

Hannah pulling seawater samples from a CTD Carrousel on the R/V Oceanus off the coast of Oregon

To study the effect of ocean acidification on Dungeness crab, Hannah simulates a variety of ocean conditions in sealed chamber where she can control oxygen and carbon dioxide levels. Then by measuring the respiration of an individual crab she can better understand the organism’s stress response to a range of oxygen and carbon dioxide ratios. Hannah hopes that her work will provide a template for measuring the tolerance of other animals to changes in ocean chemistry. She is also interested in the interplay between science, management, and policy, and plans to share her results with local managers and decision makers.

Hannah working the night shift on the R/V Oceanus

Growing up in Connecticut, Hannah spent a lot of time on the water in her dad’s boat, and developed an interest in marine science. Hannah majored in Marine Science at Boston University where she participated in a research project which used stable isotope analysis to monitor changes in food webs involving ctenophores and forage fish. Hannah also did a SEA Semester (not to be confused with a Semester at Sea) where she worked on a boat and studied sustainability in Polynesian island cultures and ecosystems.  Hannah knew early on that she wanted to go to graduate school, and after a brief adventure monitoring coral reefs off the coast of Africa, she secured her current position at Oregon State.

Tune in Sunday June, 17 at 7 pm PST to learn more about Hannah’s research and journey to graduate school. Not a local listener? Stream the show live or catch the episode on our podcast.

Hannah enjoying her favorite past time, diving!