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Coastal Ocean Projects Program/River Influences on Shelf Ecosystems

Parameters: Active Fluorescence

RISE (River Influences on Shelf Ecosystems) is a 5-year interdisciplinary study of the Columbia River plume, funded by the Coastal Ocean Program of the National Science Foundation. The UCSC component of RISE includes the Kudela Lab. Kudela’s group is responsible for remote sensing, bio-optics and phytoplankton productivity estimates using stable and radiotracer techniques ( This study addresses three hypotheses during a 5-year program (2003-2008):

  • During upwelling the growth rate of phytoplankton within the plume exceeds that in nearby areas outside the plume being fueled by the same upwelling macronutrients.

  • The plume enhances cross-margin transport of plankton and nutrients.

  • Plume-specific nutrients (iron and silicate) alter and enhance productivity on nearby shelves.

Figure 1. Satellite image of chlorophyll a distribution at the mouth of the Columbia River

RISE focuses on the highly productive Eastern Boundary river plume originating from the Columbia River located in the Pacific Northwest. Chlorophyll and productivity are not uniform along the Pacific Northwest coast– they are higher in the Columbia River plume and over the shelf north of the river mouth compared with the region south of the river mouth. The Columbia River itself provides little nitrate to the coast, although it does supply large amounts of silicate and as much dissolved iron as the Mississippi.

The PhytoFlash was integrated into the CIMT CTD January 2006 shipboard survey. Water samples were collected with Niskin bottles and processed for extracted chlorophyll a.

Graph 1. The PhytoFlash was deployed as part of the NSF sponsored RISE program off the Oregon/Washington coast. Samples were collected from Niskin bottles, dark adapted for 30 minutes, and then run in laboratory mode. As expected there was a decrease in F

Author: Raphael Kudela

Institution: UC Santa Cruz

Location: Columbia River, Oregon/Washington, USA

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