Science Inventory

Wetland water quality patterns and anthropogenic pressure associations across the continental USA

Citation:

Trebitz, A. AND A. Herlihy. Wetland water quality patterns and anthropogenic pressure associations across the continental USA. WETLANDS. The Society of Wetland Scientists, McLean, VA, , N/A, (2023). https://doi.org/10.1007/s13157-023-01754-8

Impact/Purpose:

The manuscript presents water quality data collected under the 2016 NARS National Wetland Condition Assessment. A primary finding of the paper is that across the USA, water quality patterns and associations to anthropogenic stressors in wetlands mirror those for other aquatic resources.

Description:

Anthropogenic impacts on lake and stream water quality are well established but have been much less studied in wetlands. Here we use data from the 2016 National Wetland Condition Assessment to characterize water quality and its relationship to anthropogenic pressure for inland wetlands across the conterminous USA. Water samples obtained from 525 inland wetlands spanned pH from <4 to >9 and 3 to 5 orders of magnitude in ionic strength (chloride, sulfate, conductivity), nutrients (total N and P), turbidity, planktonic chlorophyll, and dissolved organic carbon (DOC). Anthropogenic pressure levels were evaluated at two spatial scales – an adjacent scale scored from field checklists, and a catchment scale indicated by percent agricultural plus urban landcover. Pressure at the two spatial scales were uncorrelated and varied considerably across regions and wetland hydrogeomorphic types. Both adjacent- and catchment-scale pressure associated with elevated ionic-strength metrics; chloride elevation was most evident in road-salt using states, and sulfate was strongly elevated in sites with coal mining nearby. Nutrients were elevated in association with catchment-scale pressure; concomitant changes were not seen in chlorophyll but algae-dominated turbidity increased with catchment-scale pressure whereas sediment-dominated turbidity increased with adjacent-scale pressure. Acidic pH and high DOC occurred primarily in upper Great Lakes and eastern seaboard sites with low anthropogenic pressure, indicating natural organic acid sources. Ionic strength and nutrients responded to catchment-scale pressure even in Flats and closed Depression and Lacustrine sites, which indicates connectivity rather than isolation from upland anthropogenic pressures even for wetland hydrogeomorphic types lacking inflowing streams.