Contributed Session.
Lead Organizer: Luisa Galgani, University of Siena (luisa.galgani@icloud.com)
Presentations
06:00 PM
RESTORATION INSIGHTS: EVALUATING RIVER HEALTH THROUGH DISSOLVED ORGANIC CARBON COMPOSITION DYNAMICS (8899)
Primary Presenter: Emily Coronado, University of North Texas (coronadoemily2020@gmail.com)
Most of the world’s rivers have been substantially modified by human activities. A notable example is the Upper Clark Fork River (UCFR) in western Montana, USA, where historic mining and floods have resulted in the largest U.S. Environmental Protection Agency superfund site. Ecological restoration in the UCFR and floodplains included the removal of metal-laden floodplain soils, reconnecting the floodplains to the main stem, and re-vegetation of over 70 km of river. Restoration activities were expected to recover “healthy” ecosystem signatures and shift biogeochemical processes. The river’s dissolved organic carbon (DOC) was measured qualitatively (by absorbance spectroscopy and 3D excitation-emission matrix fluorescence spectroscopy) and quantitatively (DOC concentrations). We analyzed the DOC data for changing amounts of terrestrial signatures to determine restoration effects on river health annually across five years (2017-2022). DOC composition varied seasonally and annually. These data were paired with UCFR hydrologic flow patterns (snow melt onset, spring runoff, and base flow) to understand how ecological regimes change across seasons and throughout the summer with increased biological activity. Aromatic DOC composition measured by absorbance was greater in the headwaters where more intense floodplain restoration efforts occurred. We anticipate an increase in allochthonous terrestrial DOC delivered to the river reflecting successful floodplain-to-river connectivity from restoration efforts.
06:00 PM
METALS, NUTRIENTS, AND RESTORATION: UNRAVELING THE FUTURE OF THE UPPER CLARK FORK RIVER, MONTANA (9062)
Primary Presenter: Arya Mohanan, University of North Texas, Denton, Texas 76201 USA (aryamohanan@my.unt.edu)
The Upper Clark Fork River (UCFR) has a long history of contamination, including a flood in 1908 where mine tailings containing heavy metals were distributed across the channel and floodplain. In 2013, a US EPA “superfund” (CERCLA) decision led to planning the substantial remediation of the river’s floodplain and vegetation, in efforts to mitigate the influence of heavy metal contamination on the ecosystem. This provided a unique opportunity to study the recovery of UCFR ecosystem as restoration continues. Broadly, we aim to learn how river ecosystem structure and function respond to the simultaneous influences of changing nutrient abundance and hydrologic connectivity due to large-scale floodplain restoration. We identified three goals (1) how restoration in the headwaters will alter the metabolic character of the aquatic ecosystem associated with enhanced periodic floodplain inundation, (2) use of geochemical approaches to address how river metals bind with dissolved organic carbon (DOC) molecules and influence its bioavailability to microbes and invertebrates, and (3) how restoration and changing nutrient availability influence biogeochemical and ecological gradients that extend downstream. We are working to integrate biological, chemical, and hydrological data to pinpoint the timing of nutrient delivery that influences longitudinal patterns seasonally and annually in the UCFR over five years. Further, we will identify the key drivers of DOC processes shaping UCFR's biogeochemical patterns, using a combination of quantitative and qualitative DOC measurements.
06:00 PM
Exploring Metal Bioaccumulation in Freshwater Mollusks of the Susquehanna River Basin (9745)
Primary Presenter: Sydney Witter, Juniata College (wittese21@juniata.edu)
Heavy metal bioaccumulation in freshwater mollusks has been used to monitor the water quality of streams. Snails and clams, being grazers and filter feeders, are especially proficient in concentrating the metals found in the water, providing a more dynamic understanding of low-level and intermittent sources of metal pollution. The aims of this study were one, to determine if bioaccumulation was occurring, and two to determine the sources of these metals. The research was conducted by collecting water samples, Asian clams (Corbicula fluminea), and river snails (Pleurocera sp.) in 9 micro watersheds in the Susquehanna River Basin. We measured the heavy metal bioaccumulation using ICP-OES and ICP-MS spectrometers. We tested for 5 elements: copper, lead, magnesium, iron, and zinc. Collection sites were selected for the presence of Corbicula fluminea and Pleurocera sp., the history of aquatic macroinvertebrate collection, and existing water quality samples. Snails consistently showed higher metal accumulation levels than clams taken from the same site collection location. Concentrations in both species vary by collection site. Preliminary results say that watersheds with higher agricultural land use have higher metal accumulations in the mollusks.
CS18P - River and Stream Ecology
Description
Time: 6:00 PM
Date: 29/3/2025
Room: Exhibit Hall A