Life Sciences Commons^™

Improving Lake Mixing Process Simulations In The Community Land Model By Using K Profile Parameterization, Qunhui Zhang, Jiming Jin, Xiaochun Wang, Phaedra E. Budy, Nick Barrett, Sarah E. Null

Watershed Sciences Faculty Publications

We improved lake mixing process simulations by applying a vertical mixing scheme, K profile parameterization (KPP), in the Community Land Model (CLM) version 4.5, developed by the National Center for Atmospheric Research. Vertical mixing of the lake water column can significantly affect heat transfer and vertical temperature profiles. However, the current vertical mixing scheme in CLM requires an arbitrarily enlarged eddy diffusivity to enhance water mixing. The coupled CLM-KPP considers a boundary layer for eddy development, and in the lake interior water mixing is associated with internal wave activity and shear instability. We chose a lake in Arctic Alaska and …

Impacts Of Eutrophication On Benthic Invertebrates & Fish Prey Of Birds In Farmington And Bear River Bays Of Great Salt Lake, Trip Armstrong, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

Farmington Bay’s watershed is primarily in the heavily populated metropolitan Salt Lake City, and consequently, it receives approximately 50% of its inflow from nutrient‐ rich wastewater releases. The high nutrient loads make it eutrophic and reducing the loading has been suggested to reduce blooms of toxic cyanobacteria. However, the bay also supports thousands of wading birds and waterfowl, and there is concern that reducing nutrient inflows might reduce the production of bottom‐dwelling insects and other invertebrates that the birds rely upon.

Estimating Total And Bioavailable Nutrient Loading To Utah Lake From The Atmosphere, Janice Brahney

Watershed Sciences Faculty Publications

Anthropogenic activities have led to increases in the emission, atmospheric transport, and deposition of key nutrients. In addition, climate change along with anthropogenic soil disturbance has led to recent increases in the mobilization and transport of soils and other particles through the atmosphere, collectively described here as dust. These increased emissions have led to growing interest and concern over the composition of atmospheric deposition and total loading of nutrients to aquatic systems. In the last several decades, much effort has been directed towards the measurement and modeling of nitrogen deposition through wet and aerosol deposition. Less is known about the …

Effects Of Severe Water Stress On Maize Growth Processes In The Field, Libing Song, Jiming Jin, Jianqiang He

Watershed Sciences Faculty Publications

In this study, we investigated the effects of water stress on the growth and yield of summer maize (Zea mays L.) over four phenological stages: Seedling, jointing, heading, and grain-filling. Water stress treatments were applied during each of these four stages in a water-controlled field in the Guanzhong Plain, China between 2013 and 2016. We found that severe water stress during the seedling stage had a greater effect on the growth and development of maize than stress applied during the other three stages. Water stress led to lower leaf area index (LAI) and biomass owing to reduced intercepted photosynthetically active …

Climate Change Accelerates Recovery Of The Tatra Mountain Lakes From Acidification And Increases Their Nutrient And Chlorophyll A Concentrations, Jiří Kopáček, Jiří Kaňa, Svetlana Bičárová, Janice Brahney, Tomáš Navrátil, Stephen A. Norton, Petr Porcal, Evžen Stuchlik

Watershed Sciences Faculty Publications

We evaluated changes in the concentration of cations, anions, nutrients (dissolved organic carbon, DOC; phosphorus, P; and nitrogen forms including nitrate, NO₃⁻ and total organic nitrogen, TON), and chlorophyll a (Chl-a) in 31 Tatra Mountain lakes in Slovakia and Poland during their recovery from acidic deposition (1992–2018). Typical effects of decreasing acidic deposition on the lakes’ water composition, such as decreasing base cation concentrations, were confounded by climate change and catchment characteristics, including areal proportions of well-developed soils and scree. A climate-related increase in physical erosion provided freshly exposed unweathered granodiorite (the dominant bedrock) to chemical …

The Future Of Blue Carbon Science, Peter I. Macreadie, Andrea Anton, John A. Raven, Nicola Beaumont, Rod M. Connolly, Daniel A. Friess, Jeffrey J. Kelleway, Hilary Kennedy, Tomohiro Kuwae, Paul S. Lavery, Catherine E. Lovelock, Dan A. Smale, Eugenia T. Apostolaki, Trisha Brooke Atwood, Jeff Baldock, Thomas S. Bianchi, Gail L. Chmura, Bradley D. Eyre, James W. Fourqurean, Jason M. Hall-Spencer, Mark Huxham, Iris E. Hendriks, Dorte Krause-Jensen, Dan Laffoley, Tiziana Luisetti, Núria Marbà, Pere Masque, Karen J. Mcglathery, J. Patrick Megonigal, Daniel Murdiyarso, Bayden D. Russell, Rui Santos, Oscar Serrano, Brian R. Silliman, Kenta Watanabe, Carlos M. Duarte

Watershed Sciences Faculty Publications

The term Blue Carbon (BC) was first coined a decade ago to describe the disproportionately large contribution of coastal vegetated ecosystems to global carbon sequestration. The role of BC in climate change mitigation and adaptation has now reached international prominence. To help prioritise future research, we assembled leading experts in the field to agree upon the top-ten pending questions in BC science. Understanding how climate change affects carbon accumulation in mature BC ecosystems and during their restoration was a high priority. Controversial questions included the role of carbonate and macroalgae in BC cycling, and the degree to which greenhouse gases …

Relating Spatial Patterns Of Stream Metabolism To Distributions Of Juveniles Salmonids At The River Network Scale, Matthew J. Kaylor, Seth M. White, W. Carl Saunders, Dana R. Warren

Watershed Sciences Faculty Publications

Understanding the factors that drive spatial patterns in stream ecosystem processes and the distribution of aquatic biota is important to effective management of these systems and the conservation of biota at the network scale. In this study, we conducted field surveys throughout an extensive river network in NE Oregon that supports diminishing populations of wild salmonids. We collected data on physical habitat, nutrient concentrations, biofilm standing stocks, stream metabolism (gross primary production [GPP] and ecosystem respiration [ER]), and ESA‐listed juvenile salmonid density from approximately 50 sites across two sub‐basins. Our goals were to (1) to evaluate network patterns in these …

Rooting Depth And Extreme Precipitation Regulate Groundwater Recharge In The Thick Unsaturated Zone: A Case Study, Jin Shao, Bingcheng Si, Jiming Jin

Watershed Sciences Faculty Publications

Many modeling efforts have been made for shallow soil, but little has been done in deep-rooted ecosystems, especially on the long-term impact of deep-rooted vegetation to understand the impact of vegetation type on hydrological processes. In this study, we used the Community Land Model (CLM) version 4.0 to simulate the soil water dynamics and groundwater recharge with shallow-rooted and deep-rooted vegetation cover in the critical soil zone of 100 m thickness. We selected winter wheat and summer maize to represent shallow-rooted vegetation and apple trees as deep-rooted vegetation growing in the semi-humid Loess Plateau of China over the period of …

Twentieth Century Geomorphic Changes Of The Lower Green River In Canyonlands National Park, Utah: An Investigation Of Timing, Magnitude And Process, Alexander E. Walker, John C. Schmidt, Paul E. Grams

Watershed Sciences Faculty Publications

Since the early 20^th century, the Green River, the longest tributary of the Colorado River, has narrowed, decreasing available riparian and aquatic habitat.

Initially, the widespread establishment of non-native tamarisk was considered to be the primary driver of channel narrowing. An alternative hypothesis postulated that changes in hydrology drove narrowing. Reductions in total streamflow and changes to flow regime occurred due to wide-spread water development, decreased snowmelt flood magnitude, and the increased cyclicity of wet and dry years. The two hypotheses agree on channel narrowing, but each influences modern river management differently. A tamarisk-driven model of narrowing implies that …

Marine Reserves Shape Seascapes On Scales Visible From Space, Elizabeth M. P. Madin, Alastair R. Harborne, Aaron M. T. Harmer, Osmar J. Luiz, Trisha Brooke Atwood, Brian J. Sullivan, Joshua S. Madin

Watershed Sciences Faculty Publications

Marine reserves can effectively restore harvested populations, and ‘mega-reserves’ increasingly protect large tracts of ocean. However, no method exists of monitoring ecological responses at this large scale. Herbivory is a key mechanism structuring ecosystems, and this consumer–resource interaction's strength on coral reefs can indicate ecosystem health. We screened 1372, and measured features of 214, reefs throughout Australia's Great Barrier Reef using high-resolution satellite imagery, combined with remote underwater videography and assays on a subset, to quantify the prevalence, size and potential causes of ‘grazing halos’. Halos are known to be seascape-scale footprints of herbivory and other ecological interactions. Here we …

The Power Of Environmental Observatories For Advancing Multidisciplinary Research, Outreach, And Decision Support: The Case Of The Minnesota River Basin, K. B. Gran, C. Dolph, A. Baker, M. Bevis, S. J. Cho, J. A. Czuba, B. Dalzell, M. Danesh-Yazdi, A. T. Hansen, Sara A. Kelly, Z. Lang, J. Schwenk, Patrick Belmont, J. C. Finlay, P. Kumar, S. Rabotyagov, G. Roehrig, Peter Wilcock, E. Foufoula-Georgiou

Watershed Sciences Faculty Publications

Observatory‐scale data collection efforts allow unprecedented opportunities for integrative, multidisciplinary investigations in large, complex watersheds, which can affect management decisions and policy. Through the National Science Foundation‐funded REACH (REsilience under Accelerated CHange) project, in collaboration with the Intensively Managed Landscapes‐Critical Zone Observatory, we have collected a series of multidisciplinary data sets throughout the Minnesota River Basin in south‐central Minnesota, USA, a 43,400‐km2 tributary to the Upper Mississippi River. Postglacial incision within the Minnesota River valley created an erosional landscape highly responsive to hydrologic change, allowing for transdisciplinary research into the complex cascade of environmental changes that occur due to hydrology …

Guidelines For Reporting And Archiving 210pb Sediment Chronologies To Improve Fidelity And Extend Data Lifecycle, Colin J. Courtney Mustaphi, Janice Brahney, Marco A. Aquino-Lopez, Simon Goring, Kiersten Orton, Alexandra Noronha, John Czaplewski, Quinn Asena, Sarah Paton, Johnny Panga Brushworth

Watershed Sciences Faculty Publications

Radiometric dating methods are essential for developing geochronologies to study Late Quaternary environmental change and ²¹⁰Pb dating is commonly used to produce age-depth models from recent (within 150 years) sediments and other geoarchives. The past two centuries are marked by rapid environmental socio-ecological changes frequently attributed to anthropogenic land-use activities, modified biogeochemical cycles, and climate change. Consequently, historical reconstructions over this recent time interval have high societal value because analyses of these datasets provide understanding of the consequences of environmental modifications, critical ecosystem thresholds, and to define desirable ranges of variation for management, restoration, and conservation. For this information …

Mountain Lakes: Eyes On Global Environmental Change, K. A. Moser, J. S. Baron, Janice Brahney, I. A. Oleksy, J. E. Saros, E. J. Hundey, S. A. Sadro, J. Kopáček, R. Sommaruga, M. J. Kainz, A. L. Strecker, S. Chandra, D. M. Walters, D. L. Preston, Et Al.

Watershed Sciences Faculty Publications

Mountain lakes are often situated in protected natural areas, a feature that leads to their role as sentinels of global environmental change. Despite variations in latitude, mountain lakes share many features, including their location in catchments with steep topographic gradients, cold temperatures, high incident solar and ultraviolet radiation (UVR), and prolonged ice and snow cover. These characteristics, in turn, affect mountain lake ecosystem structure, diversity, and productivity. The lakes themselves are mostly small, and up until recently, have been characterized as oligotrophic. This paper provides a review and update of the growing body of research that shows that sediments in …

Increased Dust Deposition In New Zealand Related To Twentieth Century Australian Land Use, Janice Brahney, Ashley P. Ballantyne, Marcus Vandergoes, Troy Baisden, Jason C. Neff

Watershed Sciences Faculty Publications

Mineral aerosols (dust) generated in the dryland regions of Australia have the potential to reach New Zealand through atmospheric transport. Although a large portion of dust in New Zealand originates in Australia, little is known about how dust deposition has varied over time in New Zealand or what may have caused this variation. We used geochemical dust proxies to examine the recent history of dust deposition to two alpine lakes in Kahurangi National Park, South Island, New Zealand. Geochemical indicators suggest that dust deposition began to increase around 1900, with the greatest deposition rates occurring from ~1920 to ~1990. In …

Modelling Braided River Morphodynamics Using A Particle Travel Length Framework, Alan Kasprak, James Brasington, Konrad Hafen, Richard D. Williams, Joseph Michael Wheaton

Watershed Sciences Faculty Publications

Numerical models that predict channel evolution are an essential tool for investigating processes that occur over timescales which render field observation intractable. The current generation of morphodynamic models, however, either oversimplify the relevant physical processes or, in the case of more physically complete codes based on computational fluid dynamics (CFD), have computational overheads that severely restrict the space–time scope of their application. Here we present a new, open-source, hybrid approach that seeks to reconcile these modelling philosophies. This framework combines steady-state, two-dimensional CFD hydraulics with a rule-based sediment transport algorithm to predict particle mobility and transport paths which are used …

Simulation Model For Collaborative Decision Making On Sediment Source Reduction In An Intensively Managed Watershed, Se Jong Cho, Peter Wilcock, Patrick Belmont, Karen B. Gran, Benjamin F. Hobbs

Watershed Sciences Faculty Publications

We developed a watershed sediment source and delivery model for use in evaluating conservation trade‐offs in southern Minnesota, where sediment loading has been identified as a priority and there is substantial public investment in cleaner water. The model was developed in a stakeholder process and links user‐specified management options to reductions in sediment loading at the outlet of a 2,880‐km2 intensively farmed watershed. The simulation model was formulated to allocate total sediment load among sources, which provides robustness to the model by constraining the relative magnitude of sediment loads and their reduction. A novel topographic filtering approach was used to …

Emerging Reservoir Delta‐Backwaters: Biophysical Dynamics And Riparian Biodiversity, Malia A. Volke, W. Carter Johnson, Mark D. Dixon, Michael L. Scott

Watershed Sciences Faculty Publications

Deltas and backwater‐affected bottomlands are forming along tributary and mainstem confluences in reservoirs worldwide. Emergence of prograding deltas, along with related upstream hydrogeomorphic changes to river bottomlands in the backwater fluctuation zones of reservoirs, signals the development of new and dynamic riparian and wetland habitats. This study was conducted along the regulated Missouri River, USA, to examine delta‐backwater formation and describe vegetation response to its development and dynamics. Our research focused specifically on the delta‐backwater forming at the confluence of the White River tributary and Lake Francis Case reservoir. Objectives of the research were to: (1) describe and analyze the …

Timescale Dependence In River Channel Migration Measurements, Mitchell Donovan, Patrick Belmont

Watershed Sciences Faculty Publications

Accurately measuring river meander migration over time is critical for sediment budgets and understanding how rivers respond to changes in hydrology or sediment supply. However, estimates of meander migration rates or streambank contributions to sediment budgets using repeat aerial imagery, maps, or topographic data will be underestimated without proper accounting for channel reversal. Furthermore, comparing channel planform adjustment measured over dissimilar timescales are biased because short‐ and long‐term measurements are disproportionately affected by temporary rate variability, long‐term hiatuses, and channel reversals. We evaluate the role of timescale dependence for the Root River, a single threaded meandering sand‐ and gravel‐bedded river …