Carbon Biogeochemistry and Export Governed by Flow in a Non-Perennial Stream
2023 - Kristen A. Bretz, Natalie N. Murphy, Erin R. Hotchkiss

Non-perennial headwaters experience extremes in flow conditions that likely influence carbon fate. As surface waters contract through dry periods, reconnect during storms, and re-expand or dry again, there is a great deal of variability in carbon emissions and export. We measured discharge, dissolved oxygen, carbon dioxide (CO2), and dissolved organic carbon (DOC) continuously in a persistent pool at the base of a non-perennial, forested headwater stream in the southeastern United States to characterize how flow changes affect carbon emissions and export as the stream expands and shrinks. We also compared carbon concentrations and export during different stream flow categories before and after fall wet-up.
Unexpected functional diversity of stream biofilms within and across proglacial floodplains despite close spatial proximity
2023 - Grégoire Michoud, Tyler J. Kohler, Hannes Peter, Jade Brandani, Susheel Banu Busi, Tom J. Battin

High-mountain streams are particularly vulnerable to climate change because they intimately interface with the cryosphere. As glaciers shrink and snowpack diminishes, proglacial streams will eventually shift from being glacier-fed to streams fed by groundwater, snowmelt and precipitation. This shift will affect both the flow regime and physico-chemical characteristics of streams, possibly also the structure and function of their benthic microbiome. Here, we applied genome-resolved metagenomics to benthic biofilms from glacier-fed streams and their groundwater-fed tributaries within three proglacial floodplains in the Swiss Alps.
Homogeneous Environmental Selection Structures the Bacterial Communities of Benthic Biofilms in Proglacial Floodplain Streams
2023 - Jade Brandani, Hannes Peter, Stilianos Fodelianakis, Tyler J. Kohler, Massimo Bourquin, Grégoire Michoud, Susheel Bhanu Busi, Leila Ezzat, Stuart Lane, Tom J. Battin

In proglacial floodplains, glacier recession promotes biogeochemical and ecological gradients across relatively small spatial scales. The resulting environmental heterogeneity induces remarkable microbial biodiversity among proglacial stream biofilms. Yet the relative importance of environmental constraints in forming biofilm communities remains largely unknown. Extreme environmental conditions in proglacial streams may lead to the homogenizing selection of biofilm-forming microorganisms. However, environmental differences between proglacial streams may impose different selective forces, resulting in nested, spatially structured assembly processes.
Analysis of the Simulation of the Hydraulics of a Sacramento-San Joaquin Delta Marsh with a Mesocosm
2022 - Rupali Ashok Sigi

The Sacramento – San Joaquin Delta has been facing the major issue of land subsidence within the last century. This has created a high risk of failure of existing levees that have been protecting the area from flooding. Land subsidence below sea level is also creating the risk of salinity intrusion into the freshwater system of the Delta. Wetlands in the Delta help reduce oxidation of the land and compaction of the peats, which assist with reversal of land subsidence. These wetlands need to be re-established and maintained in the Delta.
A Holistic Approach to Study Groundwater-Surface Water Modifications Induced by Strong Earthquakes: The Case of Campiano Catchment (Central Italy)
2022 - Elisa Mammoliti, Davide Fronzi, Costanza Cambi, Francesco Mirabella, Carlo Cardellini, Emiliano Patacchiola, Alberto Tazioli, Stefano Caliro and Daniela Valigi

Carbonate aquifers are characterised by strong heterogeneities and their modelling is often a challenging aspect in hydrological studies. Understanding carbonate aquifers can be more complicated in the case of strong seismic events which have been widely demonstrated to influence groundwater flow over wide areas or on a local scale. The 2016–2017 seismic sequence of Central Italy is a paradigmatic example of how earthquakes play an important role in groundwater and surface water modifications. The Campiano catchment, which experienced significant discharge modifications immediately after the mainshocks of the 2016–2017 seismic sequence (Mmax = 6.5) has been analysed in this study.
The use of Rhodamine WT for the characterization of hydraulic residence times in wetlands
2020 - Rachael Dal Porto

Objectives: 1. Determince hyrdraulic residence time and related parameters in Delta wetlands using Rhodamine WT releases; 2. Analyze Rhodamine WT sorption to wetland peat in batch, mesocosm and field experiments; and 3. Determine how Rhodamine WT tracer dye sorption affects the calculation of residence time and other parameters.
Comparison between Periodic Tracer Tests and Time-Series Analysis to Assess Mid- and Long-Term Recharge Model Changes Due to Multiple Strong Seismic Events in Carbonate Aquifers
2020 - Davide Fronzi, Diego Di Curzio, Sergio Rusi, Daniela Valigi and Alberto Tazioli

Understanding the groundwater flow in carbonate aquifers represents a challenging aspect in hydrogeology, especially when they have been struck by strong seismic events. It has been proved that large earthquakes change springs hydrodynamic behaviour showing transitory or long-lasting variations and making their management much more difficult. This is the case of Sibillini Massif (central Italy), which has been hit by the well-known 2016–2017 seismic period. This work aims to improve the knowledge of carbonate aquifers groundwater circulation and their possible changes in the hydrodynamic behaviour, during and after a series of strong seismic events.
E-DATA: A Comprehensive Field Campaign to Investigate Evaporation Enhanced by Advection in the Hyper-Arid Altiplano
2020 - Francisco Suárez, Felipe Lobos, Alberto de la Fuente, Jordi Vilà-Guerau de Arellano, Ana Prieto, Carolina Meruane and Oscar Hartogensis

In the endorheic basins of the Altiplano, water is crucial for sustaining unique ecological habitats. Here, the wetlands act as highly localized evaporative environments, and little is known about the processes that control evaporation. Understanding evaporation in the Altiplano is challenging because these environments are immersed in a complex topography surrounded by desert and are affected by atmospheric circulations at various spatial scales. Also, these environments may be subject to evaporation enhancement events as the result of dry air advection. To better characterize evaporation processes in the Altiplano, the novel Evaporation caused by Dry Air Transport over the Atacama Desert (E-DATA) field campaign was designed and tested at the Salar del Huasco, Chile.
Interpretation of Dye Tracing Data Collected November 13–December 2, 2017, at the Savoy Experimental Watershed as part of the Advanced Groundwater Field Techniques in Karst Terrains Course, Savoy, Arkansas
2019 - Eve L. Kuniansky, Joshua M. Blackstock, Daniel M. Wagner, and J. Van Brahana

The first course on the use of advanced groundwater field techniques for karst aquifers was conducted November 13–17, 2017, at the University of Arkansas Savoy Experimental Watershed (SEW), which is located on pastures for beef livestock research conducted by the Department of Animal Sciences at the University of Arkansas at Savoy, Arkansas. The SEW is an interdisciplinary, collaborative, long-term research site for the study of animal-waste management in a mantled karst setting. The course focused on advanced field activities appropriate for karst aquifer studies: dye tracing, groundwater/surface-water interactions, geophysical methods, and geochemistry.
A Retrospective Analysis of a Constructed Stormwater Wetlands
2017 - Molina, Stephanie Mary

Sustainable stormwater management is prevalent today as many seek greener solutions for runoff collection and treatment. In most cases they are implemented as means to manage rainwater before it enters sewer systems via stormwater control measures (SCM). In other cases, SCMs are implemented to regulate nutrient and metal loads transported by stormwater runoff that flow and collect in rivers and streams. At Villanova University a Constructed Stormwater W etlands (CSW) was designed to reduce nutrient concentration and attenuate flow entering the headwaters of Mill Creek, a tributary of Schuylkill River.