Program and Agenda

Abstract

ECOLOGICAL SIGNIFICANCE OF PHOSPHORUS TRANSFORMATIONS AT THE RIVER-OCEAN INTERFACE OF THE COLUMBIA RIVER ESTUARY

Similar to many freshwater systems worldwide, the pelagic communities of the freshwater reaches of the Columbia River estuary are characterized by ortho-phosphate limitation of primary production with dissolved inorganic nitrogen to phosphorus ratios (N:P) typically far exceeding the 16:1 Redfield ratio. However, the N:P of the bulk freshwater (dissolved and particulate) material reaching the salt water interface is typically much lower than the Redfield ratio owing to the significant contribution of particle-associated phosphorus. Based on several years of shipboard sampling and in situ sensor measurements, we demonstrate that chemical and biological transformations of particle-bound phosphorus lead to the release of inorganic phosphorus in the estuarine salinity transition zone. This strongly affects the inorganic N:P and is a significant source of phosphorus for estuarine and river plume primary productivity. This source of phosphorus to the coastal environment is related to Columbia River flow and is typically offset from the timing of phosphorus supply associated with coastal upwelling; therefore, we hypothesize that particle-associated phosphorus from the river is ecologically significant for spring and early summer phytoplankton growth, when coastal upwelling is typically absent or intermittent.

ePoster:

Authors

Needoba, J. A., Oregon Health & Science University, USA, needobaj@ohsu.edu

Peterson, T. D., Oregon Health & Science University, USA, petersont@ebs.ogi.edu

Lerczak, J. A., Oregon State University, USA, jlerczak@coas.oregonstate.edu

Watson, S., Oregon Health & Science University, USA, watsoshe@ohsu.edu

Details

Poster presentation

Session #:008
Date: 2/25/2014
Time: 16:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 2038