Kathi Jo Jankowski

1 Introduction Phytoplankton play critical roles in ecosystem processing and food web dynamics in large rivers. They can comprise a large portion of primary production and be a primary source of carbon to consumers in mid to large-sized rivers (Thorp and Delong 1994; Vannote et al. 1980; Wehr and Thorp 1997). Several anthropogenic stressors have altered phytoplankton assemblages in large rivers, including eutrophication, invasive species and climate change.

Abstract Riverine silicon (Si) plays a vital role in governing primary production, water quality, and carbon cycling. Climate and land cover change have altered how dissolved Si (DSi) is processed on land, transported to rivers, and cycled through aquatic ecosystems.

First posted August 30, 2024 For additional information, contact: Director, Midcontinent Regional Director’s Office U.S. Geological Survey 1992 Folwell Avenue St. Paul, MN 55108 Contact Pubs Warehouse The U.S. Geological Survey hosted a Mississippi River Science Forum with Federal agencies; Tribal, State, and local governments located in States that border the Mississippi River; academia; and other interested stakeholders.