Determining the biogeochemical transformations of organic matter composition in rivers using molecular signatures

• DOI: 10.3389/frwa.2023.1005792
• Publication Date: 2023-03-21T04:44:10Z
• Authors: Jessica Z. Buser-...; Patricia E. Garcia; Matthew O. Schrenk; Peter J. Regier; Nicholas D. Ward; Kadir Biçe; Scott C. Brooks; Erika C. Freeman; Christian Lønborg
• Keywords: Biogeochemical Cycle; Biogeochemistry

Inland waters are hotspots for biogeochemical activity, but the environmental and biological factors that govern transformation of organic matter (OM) flowing through them still poorly constrained. Here we evaluate data from a crowdsourced sampling campaign led by Worldwide Hydrobiogeochemistry Observation Network Dynamic River Systems (WHONDRS) consortium to investigate broad continental-scale trends in OM composition compared localized events influence transformations. Samples two different compartments, sediments surface water, were collected 97 streams throughout Northern Hemisphere analyzed identify differences processes involved By using dimensional reduction techniques, identified putative transformations microbial respiration rates vary across sediment water along river continua independent latitude (18°N−68°N). In contrast, reveal small- large-scale patterns related local (sediment vs. column) reach (stream order, latitude) characteristics. These lay foundation modeling linkage between ecological signals. We further showed how spatial, physical, reactivity pools reaches yet find emergent broad-scale concentrations stream order. processing will likely change as hydrologic flow regimes shift vertical mixing occurs on spatial temporal scales. As our planet continues warm timing magnitude subsurface flows shift, understanding changes cycling systems is critical, given unknown responses consequences riverine OM.