Files
Abstract
Shallow, off-channel sloughs in the lower Columbia River provide critical habitat to 13 stocks of threatened or endangered juvenile Pacific salmon (Oncorhynchus spp.). We examined water quality parameters (temperature, dissolved oxygen and nutrients) and phytoplankton dynamics in three off-channel habitats (Whites Island, Campbell Slough, and Franz Lake Slough) that differ in terms of their inherent hydrogeomorphic features in the spring and summer months between 2011 and 2015. Both abiotic and phytoplankton data were analyzed in the context of varying flow conditions at seasonal and inter-annual time scales. The years of study included two that had higher–than-average discharge (2011, 2012), two that had near-average discharge (2013, 2014), and one that had below-average river discharge (2015), thus providing an excellent spectrum of conditions for investigation.