In recognition of the global nature of Critical Zone (CZ) science, the National Science Foundation has provided funding to the CZ Observatory (CZO) Science Across Virtual Institutes (SAVI) project to enable travel to CZO sites or pre-eminent laboratories overseas to further the investigation of the Critical Zone. A major goal of the SAVI is to develop international collaborations, including young scientists who will advance CZ science throughout their careers.
Each scholar proposed interdisciplinary CZ research with an international aspect and was able to travel to California and Alaska, Russia, and the Galápagos respectively. Read more about each of our scholars and their research below and also see the 2015 SAVI International Scholars.
Allison is a post-doctoral research fellow working with Dr. Suzanne Tank at the University of Alberta, and the Kwakshua Watersheds Program at the Hakai Institute in British Columbia (B.C.). Allison earned her Ph.D. at the University of California, Davis, and is broadly interested in the interaction between freshwater biogeochemistry and aquatic communities, as well as applications of water quality monitoring and use of biological organisms as indicators of ecosystem health.
Allison traveled to the Eel River CZO in Northern California and to the Héen Latinee Experimental Forest in southeastern Alaska to examine watershed exports across a climatic gradient of coastal temperate rainforest ecosystems. She collected stream samples from 40 watersheds and analyzed these samples for dissolved organic carbon, nitrogen, and phosphorus concentrations, as well as optical characterization of dissolved organic matter. It was observed that sites with lower temperatures and high precipitation, like B.C. and southeastern Alaska, had higher concentrations of organic carbon and organic matter largely derived from soils and terrestrial plants. In comparison, the warmer, drier sites of Northern California, were more influenced by autochthonous production of organic matter and had great nutrient exports. Stoichiometric relationships varied across the gradient. These data suggest very different sources of DOC and energy requirements across the coastal temperate rainforest. Efforts will be made to further link these data with hydrologic, climatic data, and spatial data.
Bianca Rodríguez-Cardona is a Ph.D. student at the University of New Hampshire in the Department of Natural Resources and the Environment, working with Luquillo CZO PI Dr. William McDowell. Her research focuses on aquatic biogeochemistry, more specifically, on carbon (C) and nitrogen (N) coupling in streams across different biomes.
Bianca visited the settlement of Tura in the Krasnoyarsk Krai region of the Central Siberian Plateau in Russia to understand the role of dissolved organic matter (DOM) quantity and composition on nitrogen processing in permafrost dominated streams. She performed instantaneous pulse additions across streams spanning a gradient in DOM concentrations and composition due to their fire history (3 - 100 years since the last burn). Preliminary data suggest that discharge and DOM composition are the best predictors of N uptake in Siberia rather than DOC concentrations or stoichiometric ratios. She will compare the coupling of DOM and N in arctic streams to tropical streams from the Luquillo CZO where she will also perform pulse additions of different forms of DOM (acetate, urea, leaf leachate) to determine their impact on N processing and concentrations. This comparison provides a broader scope of how energy and nutrients are retained and exported in aquatic ecosystems across biomes.
Sarah Schmitt is currently a Ph.D. student at the University of North Carolina at Chapel Hill working with Dr. Diego Riveros-Iregui and the Carbonshed Lab. She received her B.S. in environmental and ecological sciences from Elon University in 2014. Outside of school, Sarah enjoys sailing, scuba diving and hot yoga classes (despite her lack of flexibility due to her 6’0 frame).
Sarah performed parallel fieldwork in San Cristóbal Island, Galápagos and Ascension Island (UK) to understand the role of fog in water movement through the critical zone. Samples of fog water (using a custom fog collector design) and other water sources (rain, throughfall, surface water, groundwater, soil water, and plant water) were collected to establish the isotopic signature of fog to trace the contribution of fog to each water compartment in the critical zone. Initial analyses agreed with other tropical systems, as fog in Galápagos has an enriched isotopic signature when compared to rain. She also found that invasive guava utilizes more fog than does certain native plants. Utilizing wildlife camera traps, Sarah photographed fog cover at different elevations to characterize the formation, movement and dissipation of fog at a fine temporal scale. She is currently developing an algorithm for the automated processing of these images into different classes of fog cover, and hopes to combine these images with remotely sensed data to perform a long-term analysis of fog dynamics on both islands.
Joel Singley earned his B.S. in the science of natural and environmental systems from Cornell University and then taught middle school math and science for five years before beginning graduate school. Currently with the Environmental Biogeochemistry Group at the University of Colorado Boulder, Joel’s research focuses on multi-timescale hydrological and biogeochemical controls on nutrient transport dynamics in polar and alpine streams. He works in association with the Boulder Creek Critical Zone Observatory, as well as the McMurdo Dry Valleys and Niwot Ridge Long-Term Ecological Research (LTER) projects.
Joel is currently doing field work for his SAVI research and more on his research will be added soon!
Each scholar proposed interdisciplinary CZ research with an international aspect and was able to travel to the Galapagos Islands, Australia, and the Czech Republic respectively. Read more about each of our scholars and their research below.
Madelyn Percy is a PhD student and member of the Royster Society of Fellows at the University of North Carolina at Chapel Hill, where she works with Dr. Larry Benninger in the Department of Geological Sciences. A native Texan, Madelyn attended the University of Texas at Austin for her undergraduate degree in anthropology and geology, and taught high school science for five years before matriculating at UNC. Outside of school, Madelyn is an avid reader, a halfway decent dancer, and a very poor runner, and is in constant pursuit of making the perfect tortilla (both corn and flour).
Madelyn traveled to San Cristóbal Island in the Galápagos archipelago, trying to understand factors that affect pedogenesis (soil formation) on a tropical island basalt. She has surveyed four sites at different elevations across the island, which correspond to different microclimatic zones, seeking to describe the distribution of topsoil moisture using the electrical conductivity of the soil. She has also sampled the soil at different depths via augering and the excavation of soil pits for chemical analysis. While in the Galápagos, her team noted that the distribution of soil moisture was likely dependent on numerous factors, including the overlying plant type, the mineralogy and texture of the soils, the slope position, and the depth to a clay layer that acts as a low-permeability layer. Ultimately, Madelyn hopes to use her data and compare it to other tropical and oceanic islands made of basalt to understand how the parent material and climate in which a soil forms might affect pedogenesis.
Reggie Walters is from Sioux Falls, South Dakota and received a B.S. in Environmental Physical Science from Black Hills State University in Spearfish, SD and a M.S. in Hydrologic Science from Boise State University in Boise, ID. He has recently migrated from academia to a career in water resources at the Idaho Power Company, a hydroelectric company in Idaho.
Reggie traveled to the University of Queensland in Brisbane, Australia where he was able to meet with international CZO collaborators Dr. Talitha Santini and Dr. Joshua Larsen, both professors in the School of Geography, Planning and Environmental Management. This collaboration came about when Dr. Santini and Dr. Larsen met Reggie’s advisor, Dr. Alejandro Flores, during the CZO All-Hands Meeting in Fall of 2015. He visited each of the labs of each of these professors, as well as to many of the other facilities at the wonderful University of Queensland campus. Reggie’s research involves soil carbon dynamics of the Reynold’s Creek CZO and he had set out to perform simulation modeling and data analysis to compare and contrast soil carbon storage and fate in the vastly different environment of Australia. Reggie also became a part of Dr. Larsen's project involving global soil respiration rate analysis and the sensitivity of this parameter to global climate change. Reggie was able to analyze soils data from not only Idaho or Australia, but from all over the world, to get a more encompassing look at the importance of carbon stored in the ground. Reggie will continue to collaborate with Dr. Larsen and Dr. Santini in this ongoing project.
Adam Wymore is a post-doctoral researcher at the University of New Hampshire and is associated with the Luquillo Critical Zone Observatory. Adam is an aquatic biogeochemist and his research focuses on the cycling of dissolved organic matter and nutrients (e.g. nitrogen) in streams.
Adam was able to visit the Slavkov Forest CZO in the Czech Republic twice to perform experimental field work. The over-arching objective of this research is to examine the effects of experimental nitrate (NO3-) additions on concentrations of dissolved organic matter (DOM) and specifically dissolved organic nitrogen (DON). Adam uses the natural gradients provided by the Luquillo CZO and the Slavkov Forest CZO (i.e. lithology, vegetation, climate, dissolved organic carbon concentration) to better understand the role of DON as an energy or nutrient source within global ecosystems. Results indicate that in aseasonal tropical streams (i.e. Luquillo) DON primarily serves as an energy source likely due to low concentrations of dissolved organic carbon associated with these streams. In contrast, DON appears to serve as both an energy source and nutrient source in the Czech streams due to seasonal changes within the dissolved organic matter pool. Collectively these results, in addition to other experiments (e.g. New England; Wymore et al. 2015), indicate that DON is a highly bioreactive form of dissolved organic matter and its role within ecosystems can vary across Critical Zone gradients, seasons, and biomes.
Seven U.S. CZ science graduate students received funding to attend the inaugural Worldwide Universities Network (WUN) Soil Science and Climate Change summer school at the University of Western Australia (UWA). The summer school ran from January 29 til February 13, 2015 and included 3 days at UWA, a four-day “Critical Zone Soil Science and Climate Change” workshop and retreat at the UWA Future Farm, and a five-day facilitated writing retreat at the Albany campus of UWA.
The following students were awarded funds:
Video on WUN Summer School at UWA: