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Water column structure and zooplankton distribution along Trevor Channel, Barkley Sound. Andrew Hamilton. http://collections.ic.gc.ca/. Observations Strong sound scattering layer at depth in Trevor Channel Anoxic layer at depth in Trevor Channel Shallow sill restrict water mass mixing
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Water column structure and zooplankton distribution along Trevor Channel, Barkley Sound Andrew Hamilton
Observations • Strong sound scattering layer at depth • in Trevor Channel • Anoxic layer at depth in Trevor Channel • Shallow sill restrict water mass mixing • Abundant zooplankton collected during • net tows
Research Question • Is spatial variability in zooplankton abundance and • distribution related to physical oceanographic parameters? • Observations Required • Biology: Vertical and horizontal patterns of • zooplankton abundance, biomass, and diversity • Physics: Profiles of temperature, salinity, and oxygen
Significance • Zooplankton consume phytoplankton - indication of • Primary Productivity • Zooplankton consumed by higher trophic levels • (fish, whales) • Influence local fisheries, aquaculture, ecotourism • Physical - biological coupling affects entire ecosystem • (productivity, nutrient and carbon cycling)
Methods • 5 station transect along Trevor Channel • Biology: horizontal zooplankton net tows (shallow - 5m, • deep - 10m off bottom (20-170m)) • Zooplankton abundance, biomass, and diversity • Physics: CTD/oxygen profiles
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Open ocean Trevor Channel
Results • Zooplankton abundance and biomass highest • inside Trevor Channel • Zooplankton diversity highest in open ocean • Higher abundance and biomass at deep sites
W E Open Ocean Trevor Channel Low Salinity Low Oxygen
Krill behavior as recorded by acoustic doppler current profilers in the GullmarsfjordLiljebladh and ThomassonJournal of Marine Systems (2001) http://www.awi-bremerhaven.de/Eistour/krill-d.html
Oxygen saturation Oxygen deficiency Krill Maximum Zooplankton Mortality Ice
Conclusions • Zooplankton abundance and distribution is • related to water mass characteristics • Physical - biological relationship is complex • Will directly compare temperature, salinity, and • oxygen profiles to zooplankton results • More sampling helpful (vertical stratification, • duplicate net tows, phytoplankton profiles)
Acknowledgements Captain John of RV Alta Chris (for getting dirty) Josie (for tinfoil and lab work) Rich (for CTD crash course) Maite (for baking lessons) High School research assistants (for doing all the work) Thankyou!