Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Depth-stratified zooplankton net sampling in Hood Canal June to October, 2012-2013.

We conducted day/night paired zooplankton sampling in Hood Canal in June-October, 2012 and 2013. Sampling stations included Dabob, Union, Hoodsport, Duckabush, and Twanoh. A Hydrobios MultiNet (five-net capacity) was used to collect depth-stratified and full water column samples. Net mouth area was 0.25 m2; 200- and 335-um mesh nets were used to sample different size zooplankton. Nets were towed obliquely at 1-2.5 knots (slower tows for smaller mesh size), with inner and outer flow meters to measure water volume sampled. For the depth-stratified sampling, depth layers were based on the dissolved oxygen profiles from CTD casts.

In the laboratory, zooplankton were quantitatively subsampled and microscopically counted. All individuals were identified to species or larger taxonomic grouping, and by life stages for some species, within each sample.

Densities (#/m3) were calculated by species and life stage from each net.

BCO-DMO Data Processing Notes:
-Replaced spaces with underscores.
-Added ISO_DateTime_UTC column.
-Filled blank cells with "nd"
-Reformatted time to 24 hour time.
-Replaced commas with semicolons.

Description from NSF award abstract:
Low dissolved oxygen (hypoxia) is one of the most pronounced, pervasive, and significant disturbances in marine ecosystems. Yet, our understanding of the ecological impacts of hypoxia on pelagic food webs is incomplete because of our limited knowledge of how organism responses to hypoxia affect critical ecosystem processes. In pelagic food webs, distribution shifts of mesozooplankton and their predators may affect predator-prey overlap and dictate energy flow up food webs. Similarly, hypoxia may induce shifts in zooplankton community composition towards species that impede energy flow to planktivorous fish. However, compensatory responses by species and communities might negate these effects, maintaining trophic coupling and sustaining productivity of upper trophic level species. The PIs propose to answer the question "Does hypoxia affect energy flow from mesozooplankton to pelagic fish?" They approach this question with a nested framework of hypotheses that considers two sets of processes alternatively responsible for either changes or maintenance of pelagic ecosystem energy flows. They will conduct their study in the Hood Canal, WA. Unlike most hypoxia-impacted estuaries, hypoxic regions of Hood Canal are in close proximity to sites that are not affected. This makes it logistically easier to conduct a comparative study and reduces the number of potential confounding factors when comparing areas that are far apart.

Improved understanding of how hypoxia impacts marine ecosystems will benefit the practical application of ecosystem-based management (EBM) in coastal and estuarine ecosystems. Effective application of EBM requires that the impacts of human activities are well understood and that ecological effects can be tracked using indicators. This project will contribute to both of these needs. The PIs will share their findings on local and national levels with Federal, State, Tribal, and County biologists. To increase exposure of science to underrepresented groups, the PIs also will provide Native American youth with opportunities to participate in field collections and laboratory processing through summer internships. The PIs will collaborate with the NSF-funded Pacific Northwest Louis Stokes Alliance for Minority Participation and tribes from the Hood Canal region to recruit and mentor students for potential careers in marine science. This project will support several undergraduate researchers, two Ph.D. students, a post-doc, and two early-career scientists.