Jake Dytnerski
Ph.D. candidate
Research
Hong Kong has a seasonally dynamic marine environment. Summer sea surface temperatures can exceed 30°C whereas winter temperatures can drop below 15°C. This range in temperature allows for year-round coral communities, and abundant growth of macroalgae in the winter. For my PhD, I am researching the role of the long-spined sea urchin, Diadema setosum, in the ecosystem, here in Hong Kong. Much work has been done on Diadema antillarum in the Caribbean, and some work has been done on the D. setosum as a bioeroder of coral reefs in the tropics. However, little is known about which marcoalgae these urchins feed on; how they affect the seasonal patterns of macroalgae growth and distribution; if the urchins target living corals here in Hong Kong or just the turf algae that grows on the dead skeletons of the corals. Answering these questions will help understand the food sources of the urchins and how their energy stores vary with the seasonal change in food abundance. I am also interested in the connectivity of the populations of D. setosum across its range, as they can be found from the East coast of Africa to French Polynesia, from Honshu, Japan to NSW, Australia. I want to compare the physiological performance of the urchins from stable tropical environments and highly variable environments to determine if they show extensive physiological plasticity, or if populations have adapted to variable environments. This will allow me to predict how these important grazers will cope with future conditions across their range.
Education
2016: Bachelor of Science, Honours Marine Biology, University of British Columbia, Canada
2013: Arts and Science Diploma: Biology, Langara College, Canada
Awards
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2015: Dean of Science Scholarship – Biology research grant
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2013: Betty and Tony Pletcher Memorial Scholarship – For Achievement in Biology
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2012: Real Estate Foundation Biology Student Bursary – Bursary for Biology students
Human impacts on ecosystems
Humans tend to use the environment in two ways: we either take resources from the ocean, such as in fishing, or we use the environment to dispose of our waste, such as nutrient pollution and CO2 emissions which lead to climate change.
It is not enough to show how we damage the ocean with our activities, but rather that we need to provide information on how we can both improve the environment by changing policy and activities and also sustainably develop our use of the ocean’s resources.
Transgenerational Adaptation of Intertidal Copepods to Global Change
This project examines the influences of global climate change derived multi-stressors on the physiology and adaptation mechanisms of an intertidal copepod. It aims to understand how these organisms will adapt to climate change through multi-generations. The project also develops new methods of examining transgenerational adaptation by implementing environmental rate of change and environmental variability.
Impact of Heatwaves and Ocean Acidification on Subtidal Gastropods
The rapid increase of global temperature, resulting from anthropogenic greenhouse gas emmisions, is increasing the frequency of extreme events such as heatwaves. Coupled with an acidifying ocean, an increasing amount of stress is being imposed on marine organisms. This project is examining the potential for short-term acclimation and the impacts of multi-stressors on subtital grazing gastropods.
Thermal Plasticity and Local Adaption of Marine Herbivores
This biogeographic study assesses the physiological ability of various populations of sea urchins to tolerate thermal stress. Environmentally stable tropical populations (Thailand) are compared to more variable (Hong Kong) and extreme (Japan) populations under similar thermal conditions to assess thermal plasticity. Transcriptomic analysis will provide an insight into the adaptation of populations to local conditions. Understanding the limits of urchin thermal plasticity and potential adaptations will provide insight into future urchin distributions and their functions within the ecosystem, in a warming ocean.
Seasonal cycle of Sargassum hemiphyllum ; the role of microbial communites and nutrient gradients
In the Northwest Pacific, the seasonal monsoon contributes to the senescence of habitat-forming algal species in spring and summer, leading to accumulation of algal biomass on the soft benthos. However, little is known about the fate of this seasonal detrital material or the microbial community that directly decomposes this algal matter. As Sargassum is one of the most important coastal algal genera occupying a wide geographic area along the coast of multiple east Asian countries, characterizing microbial communities that use the same algal resource and understanding any changes and differences may shed lights on the ecological role of both the macroalgae and the microbial community in these systems.
Thermal Tolerance of Invertebrate Larvae
This project is undertaken in collaboration with Professor Maria Byrne at the Sydney Institute of Marine Science to investigate the effects of thermal stress on invertebrate larvae. The full research article can be found on the SIMS website embedded below:
