Diatoms of the intertidal environments of Willapa Bay, Washington, USA as a sea-level indicator

An understanding of the modern relationship between diatom species and elevation is a prerequisite for using fossil diatoms to reconstruct relative sea level (RSL). We described distributions from seven transects covering unvegetated subtidal environments forested uplands four tidal wetland sites (Smith Creek, Bone River, Niawiakum Naselle River) Willapa Bay, Washington, USA. compared our dataset (320 104 samples) series environmental variables (elevation, grain-size, total organic carbon (TOCSOM), porewater salinity) hierarchical clustering ordination. While no single variable consistently explains variations in assemblages at every site, elevation, salinity, substrate (mud fraction TOCSOM) are affecting distribution along transects. Elevation was major control variability (explained 27–39% variance) (Bone River Transect 1, 2, 1 2). Salinity were controls 12–32% three (Niawiakum 1: salinity; Smith Creek 2: TOCSOM). Analyses combined regional all suggest that driver with salinity co-varying an gradient. identify narrow tolerances can serve as indicator specific environments. Despite site-specific distribution, provides important be used RSL Bay.