LTER Related Oral Sessions at American Geophysical Union Meeting (2019)

• Kate Tully University of Maryland, College Park, chair Soils and Environmental Quality Division of the SSSA
• Eric Davidson University of Maryland Center for Environmental Science, Former President of the AGU
• Jill Baron Colorado State University, Former President of the ESA
• Xin Zhang University of Maryland Center for Environmental Science, Steering Committee Member of the Plant Nitrogen Network

Nutrients, such as nitrogen (N) and phosphorus (P), are critical for net primary productivity in agricultural and non-agricultural ecosystems, and are consequently important for food security and climate change mitigation. However, rising nutrient inputs to agricultural production and to the biosphere have severe environmental consequences. Quantifying nutrient budgets, including inputs and outputs of a defined system or a spatial boundary, is an essential step towards sustainable nutrient management, and also provides critical inputs to agronomic, biogeochemical, and climate models. Therefore, this session calls for research efforts on quantifying, analyzing, and/or projecting nutrient budgets on various system levels (e.g., crop and livestock production systems, integrated agro-food systems, natural systems subject to atmospheric deposition) and spatial scales (e.g., farms, watersheds, nations). This session aims to provide an opportunity to assess advances and challenges in existing nutrient budgeting methods and databases, and to discuss innovations for better quantification of nutrient budgets.

Conveners:

• Robert Gilmore Pontius, Clark University
• Lyndon D Estes, Princeton University
• Pontus Olofsson, Boston University
• Meha Jain, Columbia University

This AGU session explores frontiers in methods of error assessment, particularly in Land Change Science. Error assessment compares predictions to reference information. Conventions exist in various sub-fields, such as Remote Sensing and Simulation Modeling. Some conventions apply inappropriate metrics or poorly structured sampling designs. Other conventions have yet to address features in new data formats, such as object-oriented image analysis. New methods are now possible given new technologies, such as Virtual Globes and interfaces that allow volunteered information. This session focuses on methods to address existing challenges and to establish future practices.

Conveners:

• Robert Gilmore Pontius, Clark University
• James T Morris, University of South Carolina

This AGU session explores methods to characterize temporal change in coastal regions. Existing methods of measuring shoreline change include the Baseline & Transect method, which attempts to measure the shoreline movement; however, subjective decisions concerning how to draw the Baseline & Transects influence the results. A Polygon Overlay method measures shoreline change in terms of areas that transition between land and water. Remote sensing technologies are available, but such methods face many challenges, such as the tides and season. Geomorphological theory can predict trends, but rarely specifics.  This session focuses on empirical methods and theory to address existing challenges and to establish future practices.

Conveners:

• David Sailor and Paul Coseo, Arizona State University
• Chanam Lee and Bruce Dvorak, Texas A&M University

This session will focus on experiments to improve understanding of complex interacting urban environmental challenges (e.g., extreme heat, air pollution, urban flooding), with an emphasis on translation of knowledge into action to improve human health outcomes.

Two categories of experiments will be highlighted: natural experiments in which spatial or temporal variations in urban design, policies or surface characteristics result in markedly different environmental and human health outcomes; and designed experiments in which urban planners/managers, community stakeholders, and researchers collaborate in the co-design and implementation of strategies and technologies to affect urban environmental parameters with the end-goal of improving human health outcomes. In both cases presenters are asked to highlight lessons learned and barriers to effective urban environmental planning and mitigation efforts.

Conveners: 

• Sujith Ravi, Temple University
• Lixin Wang, Indiana University- Purdue University

Invited speakers: 

• Dr. Gabriel Katul, Duke University
• Dr. Patricia Saco, The University of Newcastle, Australia

Session Description:

Water is fundamental to sustain ecosystem functions in drylands, which cover 40% of the terrestrial land surface and support more than 2 billion people. In these water-limited systems a tight coupling exists between water availability, ecosystem productivity, surface energy balance, and biogeochemical cycles. Both climatic (e.g., increase in aridity, recurrent droughts) and anthropogenic factors (e.g. agriculture, grazing, energy development) are increasingly affecting the dryland water dynamics. Further, it is essential to understand the consequences of hydrological changes on other ecosystem functions. We welcome submissions focusing on the ecohydrological processes/feedbacks in drylands, their quantification using novel methodologies, and their implications on a broad range of issues including land use change, water resources, desertification, and food-energy-water nexus.

Conveners: 

• John Campbell, USDA Forest Service
• Mark Green,  Plymouth State University and Hubbard Brook LTER

Quantifying carbon storage in terrestrial ecosystems remains challenging despite the need for strategic management of the global carbon balance. Forest biomass and forest soils can be highly heterogeneous and difficult to measure. Urban trees have been characterized using allometry from closed forests, which may result in bias. In agricultural systems, understanding the impact of land use practices on soil carbon changes remains a major research need. Fortunately, new technologies are improving estimates of natural variability, thereby reducing uncertainty. For example, terrestrial LiDAR can provide detailed characterization of live and dead wood pools. At the same time, methods for characterizing uncertainty in estimates are improving.  This session will highlight studies that are aimed at understanding the uncertainty in terrestrial carbon stocks, including quantifying spatial variability. It will also highlight novel data sets and quantitative methods used in these characterizations.

Conveners:

• Benjamin Duval, New Mexico Institute of Mining and Technology
• Jennie McLaren, University of Texas-El Paso
• Daniel Cadol, New Mexico Institute of Mining and Technology

Invasive and expanding plant species have profound effects on ecosystem processes: introduced trees affect riparian hydrology, invasive grasses alter fire regimes and the range expansion of shrubs changes grassland dynamics. However, there are still knowledge gaps to be filled regarding biogeochemical effects of plant invasions on soils, nutrient cycling and greenhouse gas fluxes that provide mechanisms maintaining invasive persistence and driving expansions. Information on soil-microbial-plant interactions at local and regional scales is needed to inform progressive management strategies to re-establish native plant communities, especially in the face of anthropogenic climate change. We solicit presentations coupling biogeochemical theory with either modeling studies or field experiments on plant invasions that integrate multiple scales of ecosystem science. Our session aims to answer: how do invasive plants influence soil physio-chemistry and nutrient cycling? How do invasions and expansions impact greenhouse gas flux? What effect do invasive plants have on the soil microbial community structure?

Conveners:

• Bonnie McGill, University of Kansas
• Mallika Nocco, University of Minnesota/University of California-Davis
• Anthony Kendall, Michigan State University
• Sam Zipper, University of Victoria/University of Kansas

A leading trans-disciplinary challenge in the 21st century is how to grow more food with less water while also improving water quality, soil health, and biodiversity. This session seeks to improve agrohydrological understanding at both global and local scales and translate this understanding into sustainable, multifunctional landscapes. We seek abstracts studying water quantity and/or water quality in agricultural landscapes and the urban-rural interface. Potential topics include (but are not limited to): (i) how to harness new technologies, tools, and big data (e.g. UAVs, deep learning, Google Earth Engine) to improve water management; (ii) agroecosystem links to other earth systems, particularly climate change; (iii) hydrologic thresholds, regime shifts, and alternative stable states in agroecosystems; (iv) emerging management practices including managed aquifer recharge, deficit irrigation, precision agriculture, and designer flows; (v) food-energy-water nexus research; (vi) social dimensions of agrohydrology; and (vi) translating scientific understanding into effective management and policy.

Conveners: 

• Andrew Robison, University of New Hampshire Main Campus
• Erin Hotchkiss, Virginia Polytechnic Institute and State University
• Chris Whitney, University of New Hampshire Main Campus

Historically, understanding how ecosystem processes and biogeochemical fluxes respond to and recover from environmental change was limited by low-temporal resolution sampling that fails to capture natural variability, extreme weather events, and other disturbances. However, ecosystem processes vary over short timescales. Furthermore, recent advancements in sensor technology have allowed unprecedented examinations that alter our understanding of the timing, variability, and magnitude of ecosystem processes and biogeochemical fluxes. As such, sensor data enable scientists to identify new areas of research and test paradigms in ecosystem science. For example, high frequency dissolved oxygen and carbon dioxide sensors are providing unique perspectives on patterns in aerobic and anaerobic stream metabolism and connections with the terrestrial environment. We invite contributions highlighting novel conclusions about ecosystem processes thanks to high-frequency sensor data. We encourage submissions using sensors to advance paradigms and provide unique perspectives in terrestrial, freshwater, or marine ecosystem ecology or biogeochemistry.

Conveners:

• Maike Sonnewald, Massachusetts Institute of Technology 
• Redouane Lguensat, CNES/ IGE Grenoble
• Pierre Gentine, Columbia University 
• Patrick Gray, Duke University

As machine learning methods mature, many possibilities open in Ocean and Atmospheric Sciences for describing and understanding large data sets. Increasing volumes of data are becoming available that allow novel exploration of complex phenomena. From characterizing global dynamical regimes, improving subgridscale parameterizations and leveraging robotic technology such as drones and remote sensing, machine learning promises innovation. As a tool, machine learning can play a pivotal role as the link between theory, modelling and observational efforts. This session invites submissions that demonstrate progress in understanding both the uses and misuses of machine learning in terms of supervised, unsupervised, and active learning, as well as visual analytics. Submissions are welcomed from regional and global applications to ocean and atmospheric sciences.

Conveners:

• Trevor Keenan, Lawrence Berkeley National Lab 
• Nick Smith, Texas Tech University
• Cecilia Chavana-Bryant, Lawrence Berkeley National Lab
• Han Wang, Tsinghua University

Vegetation canopy structure and function determine global rates of photosynthesis and transpiration and, thus, heavily influence the global carbon, water, and energy cycles. Key unknowns remain regarding how plant canopies respond to both temporal and spatial mesoclimatic changes, and the within-canopy microclimate. In this session, we will explore the relative roles of leaf physiology, phenology, microclimate, and canopy structure in determining ecosystem states, traits, and rates. We are particularly interested in studies that use novel approaches to examine changes in canopy form and function, particularly those that bridge traditional boundaries with new theory, observations, and models. We encourage submissions focused on vegetation canopies at any scale, including near-surface or remote sensing techniques, field and experimental observations. We also encourage empirical and modeling submissions examining canopy processes across scales, from seconds to decades and from the leaf to the globe.

Conveners:

• James Moran (James.Moran@pnnl.gov), Pacific Northwest National Laboratory
• Paul Dijkstra, Northern Arizona University
• Steven Blazewicz, Lawrence Livermore National Laboratory

Microbial communities drive many biogeochemical processes which, as a result, impact nutrient availability, system productivity, and relevant fluxes from natural ecosystems. The complexity of these microbial communities, however, makes them challenging to study and can confound efforts to identify metabolic interactions between organisms, quantify gross and net metabolic fluxes, or reveal physiological interactions between plants, animals, and their geochemical environment.  Isotope and omics analyses have historically provided tools for exploring these systems. Emerging advances linking isotope analysis to omics approaches as well as improvements in measurement hardware are providing new insights to advance our scientific understanding of complex systems. This session seeks to include discussions on linking isotope and omics data collection, alternative isotope measurement platforms (i.e., spectroscopy and NMR), spatial isotope analysis, the use of multi- and non-traditional stable isotopes, and other related topics.  Both methodological and application-based presentations are encouraged.

Conveners:

• Samantha Rose Weintraub, National Ecological Observatory Network
• William R Wieder, National Center for Atmospheric Research
• Alejandro N Flores, Boise State University
• Kate Lajtha, Oregon State University

Soil organic matter (SOM) is a critical ecosystem variable regulated by complex physical, chemical and biological interactions across scales. Better constraints on SOM pools and fluxes are required to advance understanding and generate insight into how global change will influence SOM persistence and vulnerability. Interdisciplinary research and observation networks are collecting long term, geographically distributed data that can help elucidate mechanisms driving soil organic matter dynamics, and international efforts are working toward soil data harmonization and data-model sharing. We seek contributions investigating controls on soil organic matter using a networked, multi-site approach and/or leveraging long-term observations or experiments. Studies using novel tools, from microbial -omics to near-surface geophysical and remote sensing observations, are welcome. Contributions that discuss data dissemination, cross-site synthesis, and collaborations between empiricists and modelers within and across networks, are strongly encouraged.

Conveners:

• William R Wieder, National Center for Atmospheric Research
• Fiona Soper, Cornell University
• Sasha Reed, U.S. Geological Survey
• Cory C. Cleveland, University of Montana

Nutrients (nitrogen, phosphorus and others) have the potential to mediate plant growth and ecosystem carbon balance in response to environmental change. Despite a range of data suggesting nutrient constraints on terrestrial ecosystems, we have a poor understanding of how nutrient cycling may respond to environmental perturbations like elevated CO2, warming, and changes in the hydrologic cycle. Moreover, our inability to simulate nutrient effects on the global carbon cycle undermine efforts to accurately project carbon cycle-climate feedbacks in a changing world. At the same time, only a handful of current models even attempt to represent those interactions and feedbacks. This session aims to identify gaps in understanding and representation of modeled carbon-nutrient interactions and discuss experiments, manipulations, syntheses, and simulations that will increase our ability to predict if and how nutrients may constrain the global terrestrial carbon cycle into the future.

While the river continuum concept is now deeply embedded in our thinking about watershed biogeochemistry, we need to extend this concept to include the journey of river water through deltas, estuaries, and river plumes. This session will focus on patterns and processes between the head of tide and the open ocean that are both driven by and serve to alter river-borne constituents, including the myriad of biogeochemical changes that occur as river waters slow down, spread out, encounter wetlands and salinity, drop sediments and enable photo-oxidation, interact with invasive species and human disturbance, undergo tidal pumping with local landscapes, fix/release carbon, consume nutrients while stoking algal blooms, undergo flocculation, sorption and desorption, fuel food webs, (and more). We invite presentations that explore all the ways that biogeochemical cycling drives ecology and ecology drives biogeochemical cycling in the delta/estuarine/plume environment, with whatever tools it takes to get the job done.

Conveners

• Osvaldo Sala,Arizona State University
• Melinda Dianne Smith, Colorado State University
• Laureano Gherardi, Arizona State University

Climate change will result in an intensification of droughts in many regions of the globe. The effect of these droughts will depend on their frequency, magnitude and duration, as well as the sensitivity of ecosystems to these events, which is here defined as the rate of ecosystem change per unit decrease in precipitation. We hypothesize that ecosystem sensitivity will depend on the history of precipitation variability experienced by a site, as well as soil water-holding capacity and plant species diversity and composition. This session will host diverse studies ranging from single-site and networks of experiments to simulation modeling, and will tackle the effects of intensified drought on carbon cycle processes, and the role that historical precipitation variability and ecosystem attributes may play in determining drought sensitivity. The major outcomes of the session will be a synthesis of determinants of ecosystem sensitivity to drought and identification of future research priorities.

The 2018 National Academies of Sciences, Engineering, and Medicine report: “Branches from the Same Tree: The Integration of the Humanities and Arts with Sciences, Engineering, and Medicine in Higher Education” highlighted that educational programs mutually integrating learning experiences in the humanities and arts with science, technology, engineering, mathematics, and medicine (STEMM) lead to improved educational and career outcomes for students. This session brings together educators from across AGU to present on their efforts focusing on the integration of STEMM curricula into degree programs and developing cross-cutting transdisciplinary experiences. We invite contributions from all aspects of the university system, from students learning within an integrated program to researchers evaluating the impact of these programs on higher education to faculty developing integrative activities. In this session, attendees will have the opportunity for discussions focused on lessons learned and the next steps for the continued developed of integrated student experiences in Higher Education.

If you have any questions please feel free to contact me at mbleigh@alaska.edu or Peter Webley (primary convener) at pwwebley@alaska.edu

Conveners

• Claire Phillips, USDA-ARS
• Markus Kleber, Oregon State University
• Dan Liptzin, Soil Health Institute

Invited Speakers

• Harold van Es, Cornell University
• David Myrold, Oregon State University

Soil management practices that enhance organic matter content, minimize disturbance, and promote soil biology are increasingly viewed as critical strategies to both sequester carbon and improve soil productivity. This session will explore how soils change mechanistically under conservation practices, the implications of those changes for the productivity of working lands, and impacts on elemental budgets at farm- to global-spatial scales.

This session welcomes contributions that advance the scientific underpinnings of the soil health concept. Topics may include: links between soil physical and microbial community development, pore versus aggregate perspectives on soil structural development, soil impacts of pesticides and other inputs, and greenhouse gas implications of improved soil health. Contributions across the physical, biological, and geochemical disciplines of soil health are welcome.

Conveners:

• Keith Musselman (University of Colorado, Boulder)
• Lara Kueppers (University of California, Berkeley)
• Jia Hu (University of Arizona)
• Kendra Kaiser (Boise State University)
  

Conveners

• Stephen D Sebestyen, USDA Forest Service
• James B Shanley, USGS
• Jonathan M Duncan, Pennsylvania State University Main Campus
• Taehee Hwang, Indiana University Bloomington

Across scales, watershed, critical zone, and ecosystem studies are vital to expanding theory and discovery in hydrological, biogeochemical, and ecological process understanding. Well-studied sites provide context, especially when coupled with land management and environmental change experiments. Long-term studies and monitoring at sentinel sites have proved invaluable for detecting, documenting, and understanding fundamental processes and effects of environmental change on ecosystems. New technologies, sites, and field experiments are feeding the innovation and closing knowledge gaps. Multi-site comparisons at various temporal and spatial scales provide information needed to build theory, manage ecosystems, and inform modeling efforts. We seek contributions on these efforts, and especially encourage submissions that demonstrate societal relevance.