Zooplankton Distribution and Transport in the California Current off Oregon

Public Deposited

Downloadable Content

Download PDF


Attribute NameValues
  • This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Inter-Research and can be found at:
  • The transport and retention of zooplankton biomass in the shelf and slope regions off Oregon were studied in June 2002. A towed undulating instrument package was used with 2 pairs of Conductivity–Temperature–Depth (CTD) sensors, a fluorometer and an Optical Plankton Counter (OPC) for high resolution measurements of temperature, salinity, depth, fluorescence and zooplankton abundance. The shipboard 153 kHz Acoustic Doppler Current Profiler (ADCP) was used for current measurements in water column. Two different analytical methods for the geostrophic current fields based on ADCP current measurements were employed based on minimizing current divergence. Results revealed high zooplankton biomass values in coastal upwelling areas on the shelf and exchanges between shelf waters with high zooplankton biomass and offshelf waters with low zooplankton biomass by crossing-isobath currents. In the shelf area of Heceta Bank off Newport, Oregon shallower than the 153 m isobaths bounded between 41°44´N and 44°37´N, the standing zooplankton biomass was approximately 4×10⁴ ton C. The major flux of zooplankton biomass into the area occurred at the northern boundary at a rate of 1– 2.5×10³ ton C d⁻¹ or a specific rate of 0.03–0.06 day⁻¹ based on two different analytical methods; the flux at the southern boundary is one order of magnitude less than that of the northern boundary; and the significant flux out of the area occurred at the 153 m isobath at a rate of 0.8–3.7×10³ ton C d⁻¹ or a specific rate of 0.02–0.09 day⁻¹. These rates are comparable with the zooplankton growth and mortality rates of approximately 0.1 day⁻¹ reported in literatures within this region. The offshelf transport of zooplankton contributes significantly to biomass losses in shelf ecosystems and in turn fuels offshelf ecosystems.
Resource Type
Date Available
Date Issued
  • Wu D, Zhou M, Pierce SD, Barth JA, Cowles T (2014) Zooplankton distribution and transport in the California Current off Oregon. Mar Ecol Prog Ser 508:87-103.
Journal Title
Journal Volume
  • 508
Rights Statement
Funding Statement (additional comments about funding)
  • This research was supported by the United States National Science Foundation grant numbers OCE0002257 and OCE 0435581 to M. Zhou and OCE0435619 to T. Cowles.



This work has no parents.