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Fall 2023 Marine Sciences Interdisciplinary Seminar, Multi Speaker
December 1, 2023 @ 10:00 am - 11:15 am
Aundre Jackson: Identifying factors that affect the abundance of oysters pathogens in seawater
Vibrio spp (Vibrio species), including the oyster pathogen V. corallilyticus, are a persistent concern for oyster hatcheries in Netarts Bay, Oregon, which is vulnerable to changing environmental conditions including ocean acidification and increasing sea surface temperatures. These environmental conditions affect both the growth of oyster shells and Vibrio spp. However, it is unknown how changing environmental conditions affect V. corallilyticus to impact oyster health. To answer this question, sample water was collected at Netarts Bay to observe Vibrio spp abundance, salinity, and temperature. The most abundant Vibrio spp was V. corallilyticus, and concentrations of this pathogen were higher in Netarts Bay, compared to offshore samples. High concentrations of V. coralliilyticus were also observed in Netarts Bay during low tide and during the summer. Together, these findings suggest that upwelling of offshore water brings V.corallilyticus and other pathogens into Netarts Bay where warm conditions during low tide create the perfect conditions for the bacteria to grow abundantly, increasing the disease risk for oysters in the hatchery. This work underscores the importance of considering biological, physical, and chemical factors that affect oyster populations.
Prisca Lim – Mechanisms of upwelling around the Galapagos Archipelago
The Galapagos Islands are well known for its vast biodiversity and high number of endemic species. This rich biodiversity is the result of high nutrients entering the euphotic zone around the islands, supporting large populations of phytoplankton that feed higher level taxa throughout the archipelago. Upwelling currents transport nutrient-rich waters from the deep ocean to the euphotic zone where they can be utilized by phytoplankton, resulting in higher chlorophyll-a biomass and decreased sea surface temperature. Hence, elucidating the mechanisms of upwelling in and around the Galapagos archipelago is crucial in aiding our understanding of phytoplankton dynamics which support the rest of the marine ecosystem. Currently, it is widely accepted that upwelling around the Galapagos Islands is largely driven by the Equatorial Undercurrent (EUC), an eastward-flowing subsurface current that extends the length of the equator in the Pacific Ocean, and is forced to the surface upon collision with the islands. However, this talk will describe new research findings that demonstrate how upwelling may be more dependent on localized wind-front interactions instead of the regional impact of the EUC, warranting greater focus on such processes in the assessment and mitigation of the region’s vulnerability to climate change.
Yubeen Jeong – The Influence of the Gulf Stream Frontal Eddies on Cape Hatteras Marine Ecosystems
In the ocean, the interaction between physical and biological processes often leads to intricate dynamics. Eddies, oceanic phenomena that exist in various scales, significantly affect both physical properties and biogeochemical aspects. Studying mesoscale eddies, especially because of their intricate variability and expansive scope, is both observationally and computationally challenging. However, a recent study offers insights into a frontal eddy located just north of Cape Hatteras, examining it through comprehensive sampling of its hydrographic, biogeochemical, and optical characteristics. Globally, frontal eddies are formed in western boundary currents and there’s much to learn about their effect on marine ecosystems. Past research in the Gulf Stream’s South Atlantic Bight suggests these eddies typically dissipate past Cape Hatteras. However, new observations showed the eddy maintained a cyclonic motion and had distinct physical characteristics and phytoplankton communities compared to neighboring water masses. This study introduces a basic conceptual model, capturing the ecological effects of frontal eddies. From this, it was proposed that these eddies might play a pivotal role in supporting zooplankton, benefiting the dense and varied top predator populations near Cape Hatteras. Using data from this eddy, the authors further investigate its biogeochemical profile, compare it with Gulf Stream and shelf waters, and refine their model.