|  | 7 April 1978 LANDSAT TM image of the Columbia
      River estuary. [Image courtesy of LTER.] |  | Aerial view looking east from above entrance
      to estuary. The North Jetty is to the left and South Jetty to
      the right. [Image courtesy of R. Emmett, NMFS] | 
    
      |  | Aerial view looking SE over central region of
      estuary. |  | Aerial view looking south over Astoria, with
      Saddle Mountain on horizon. [Image courtesy of R. Emmett, NMFS] | 
    
      |  | Aerial view looking NW over marsh islands of
      Cathlamet Bay, with entrance to estuary in background. [Image
      courtesy of L. Weitkamp, NMFS] |  | Aerial view downstream of the Columbia at RiverMile
      53. The primary upstream sampling site for CRETM-LMER was located
      at the dock in the lower right corner of this view. [Image courtesy
      of L. Weitkamp, NMFS] |