BENTHOPELAGIC ZOOPLANKTON DIEL VERTICAL MIGRATION PATTERNS USING A TWO-DECADE NEAR-CONTINUOUS RECORD OF ACOUSTIC DOPPLER PROFILER IN THE ONSLOW BAY SHELF, NC

Demersal zooplankton bridge benthic and pelagic ecosystems during their daily (diel) vertical migrations (DVM). Typically, zooplankton emerge from the benthos into the water column at night and return to the seafloor during daytime. This movement is difficult to study because it requires continuous sampling over extended periods of time. The movement of planktonic particles can be inferred using seafloor mounted acoustic doppler current profilers (ADCP). UNCW’s Coastal Ocean Research and Monitoring program has an ADCP at 27m depth recording at a 1m vertical and 30-minute temporal resolution. Using acoustic target strengths, we can track the vertical movement of particles since recording started in April 2000 to date. Using this dataset, we asked the question of whether DVM patterns changed seasonally along with trends of planktonic production typical of Onslow Bay. As expected, DVM signals followed the typical pattern: up at night and at depth during daylight. However, what this dataset revealed was that this pattern shifts in time. The timing at which demersal plankton returned to the benthos became progressively later in the day, from earlier in productive months to later in the less productive months. We found that this dataset can be used to further explore bentho-pelagic coupling and how this phenomenon may affect biologic oceanographic processes. Long-term climatology of these diel shifts can help understand trophic dynamics from mesozooplankton to ichthyoplankton temporal and spatial patterns in shallow productive shelves such as those impacted by the Gulf Stream. 

Presentation Preference: Oral

Primary Presenter: Matt Bues, University of North Carolina at Wilmington (mb8003@uncw.edu)

Authors:

Christian Briseño-Avena, University of North Carolina at Wilmington  (brisenoavenac@uncw.edu)

Sutara Suanda, University of North Carolina at Wilmington  (suandas@uncw.edu)