Long-term Trends in Arctic Riverine Chemistry Signal Multi-faceted Northern Change Suzanne Tank (  suzanne.tank@ualberta.ca ) University of Alberta https://orcid.org/0000-0002-5371-6577 James McClelland (  jmcclelland@mbl.edu ) Marine Biological Laboratory Robert Spencer (  rgspencer@magnet.fsu.edu ) Florida State University Alexander Shiklomanov (  alex.shiklomanov@unh.edu ) University of New Hampshire Anya Suslova (  asuslova@woodwellclimate.org ) Woodwell Climate Research Center Florentina Moatar (  ｧorentina.moatar@inrae.fr ) INRAE Rainer Amon (  amonr@tamug.edu ) Texas A&M University, Galveston Campus https://orcid.org/0000-0002-1437-4316 Lee Cooper (  cooper@umces.edu ) University of Maryland Greg Elias (  Greg.Elias@auroracollege.nt.ca ) Western Arctic Research Center Vyacheslav Gordeev (  gord_vv@mail.ru ) Russian Academy of Sciences Christopher Guay (  cguay@hawaii.edu ) Mamala Research LLC Tatiana Gurtovaya (  tanya@cppis.ru ) South Russia Centre for Preparation and Implementation of International Projects Lyudmila Kosmenko (  l.kosmenko@gidrohim.com ) Ministry of Natural Resources and Environment of the Russian Federation Edda Mutter (  emutter@yritwc.org ) Yukon River Inter-Tribal Watershed Council Bruce Peterson (  bpeterson@mbl.edu ) Marine Biological Laboratory Bernhard Peucker-Ehrenbrink (  bpeucker@whoi.edu ) Woods Hole Oceanographic Institution https://orcid.org/0000-0002-3819-992X Peter Raymond (  peter.raymond@yale.edu )