Motivated by the study of heat diffusion, Joseph Fourier claimed that any periodic signals can be represented as a series of harmonically related sinusoids. Fourier’s idea has a profound impact in geoscience. It took one and a half centuries to complete the theory of Fourier analysis. The richness of the theory makes it suitable for a wide range of applications such as climatic time series analysis, numerical atmospheric and ocean modeling, and climatic data mining.

Global change is complex and multidimensional, making it challenging to understand how human activities affect ecosystem processes. A critical gap in this understanding is how drivers of global change broadly affect food webs. While an industry of studies documents shifts in food webs in response to anthropogenic pressures, a general synthesis is lacking. To address this, we review studies across diverse ecosystems that use stable isotope analysis, energetic food web modelling and gut content analysis to reveal the prevalence of asymmetric rewiring-a phenomenon whereby anthropogenic pressures differentially impact habitats across space, altering some energy pathways within food webs relative to others. We then highlight several examples from the literature to illustrate how this process unfolds. To explore its broader consequences, we use a simple food web model to demonstrate how asymmetric rewiring alters resilience and key ecosystem functions, such as primary and secondary production. Our synthesis uncovers a remarkably general response in food web structure to global change that needs to be better understood to protect nature and the services that human societies rely on in a rapidly changing world.

Computational models are employed to study and respond to pressing environmental issues such as groundwater contamination. This use of computational models, which often involves algorithms and uncertainty that are hidden to the public, has implications for environmental science literacy. This study applies a design-based research approach to explore how technology-infused science instruction can scaffold secondary students in developing proficiency with computational modeling of groundwater contamination as a facet of environmental science literacy. Descriptions of research-based, technology-infused learning experiences situated within a groundwater contamination issue–based context are shared, and evidence of students’ subsequent learning is presented. Findings suggest that student learning may be supported by enacting instructional experiences that scaffold students in (a) developing first concrete then increasingly abstract understanding of groundwater system structure, function, and dynamics; (b) building conceptual connections between multiple types of models and representations of a system; and (c) explicitly engaging with and judging uncertainties associated with system models, model outputs, and associated arguments. Insights are shared concerning how instructional technologies including physical models, two-dimensional representations (e.g., maps and cross-sections), and computational models may be employed in science teaching to support students in developing computational modeling competencies needed for participating in debates and discussions about socioenvironmental problems like groundwater contamination.

Fires are expected to become more frequent in many ecosystems due to climate change. Shifting fire regimes may affect soil food web interactions and impact soil functions including decomposition, nutrient cycling, and soil organic matter formation. We evaluated soil food web structure, function, and stability along a fire frequency gradient. We studied the effect of fire return interval on soil food webs in a long-term fire return interval experiment in an oak-pine savanna. We measured soil biota biomass of major microbial groups (gram positive bacteria; gram negative bacteria; arbuscular mycorrhizal (AM) fungi; saprotrophic fungi) using phospho- and neutral-lipid fatty acid assessments. We applied an energetic food web modeling framework to investigate soil food web structure, function, and stability. Soil biota community composition and biomass were conserved across the fire frequency gradient, but biomass of AM fungal storage compounds decreased with less frequent fires. Soil food web complexity decreased with FRI, driven by a loss of fungal consumers and predators. Soil food webs at 4-year fire frequencies were significantly less stable and less resilient than those at either low or high fire frequencies. These community shifts did not lead to meaningful changes in modeled C and N mineralization. Though soil food web biomass and function were conserved along the fire frequency gradient, food webs were structurally unique and not equally stable. This study reveals latent dynamics of soil communities that hint towards vulnerable food web architectures at the transition between forest and savanna ecosystems.

Historically, humans have managed food systems to maximize productivity. This pursuit has drastically modified terrestrial and aquatic ecosystems globally by reducing species diversity and body size while creating very productive, yet homogenized, environments. Such changes alter the structure and function of ecosystems in ways that ultimately erode their stability. This productivity-stability trade-off has largely been ignored in discussions around global food security. Here, we synthesize empirical and theoretical literature to demonstrate the existence of the productivity-stability trade-off and argue the need for its explicit incorporation in the sustainable management of food systems. We first explore the history of human management of food systems, its impacts on average body size within and across species and food web stability. We then demonstrate how reductions in body size are symptomatic of a broader biotic homogenization and rewiring of food webs. We show how this biotic homogenization decompartmentalizes interactions among energy channels and increases energy flux within the food web in ways that threaten their stability. We end by synthesizing large-scale ecological studies to demonstrate the prevalence of the productivity-stability trade-off. We conclude that management strategies promoting landscape heterogeneity and maintenance of key food web structures are critical to sustainable food production. A synthesis of empirical and theoretical literature shows the extent to which food production has homogenized and rewired food webs to increase productivity but with negative consequences for stability.

From 08-12 August, 2022, 32 individuals participated in a workshop, Stability and Fluctuations in Complex Ecological Systems, at the Lorentz Center, located in Leiden, The Netherlands. An interdisciplinary dialogue between ecologists, mathematicians, and physicists provided a foundation of important problems to consider over the next 5-10 years. This paper outlines eight areas including (1) improving our understanding of the effect of scale, both temporal and spatial, for both deterministic and stochastic problems; (2) clarifying the different terminologies and definitions used in different scientific fields; (3) developing a comprehensive set of data analysis techniques arising from different fields but which can be used together to improve our understanding of existing data sets; (4) having theoreticians/computational scientists collaborate closely with empirical ecologists to determine what new data should be collected; (5) improving our knowledge of how to protect and/or restore ecosystems; (6) incorporating socio-economic effects into models of ecosystems; (7) improving our understanding of the role of deterministic and stochastic fluctuations; (8) studying the current state of biodiversity at the functional level, taxa level and genome level.

Nearly a decade ago, the Framework for K-12 Science Education argued for the need to intertwine science and engineering practices, disciplinary core ideas, and crosscutting concepts in performance expectations. However, there are few empirical examples for how intertwining three dimensions facilitates learning. In this study, we used a learning progressions approach to examine how student engagement in computational thinking (science and engineering practice) intertwines with learning about the flow of water through environmental systems (disciplinary core ideas) and understanding of systems and system models (crosscutting concept). We developed three secondary-level curriculum units situated in current groundwater contamination and urban flooding contexts. Units included specially designed NetLogo computational models. Post-assessments measured student performances in computational thinking processes and understanding of hydrologic systems. Using item response theory in our analysis, we identified distinct levels of performance on a learning progression. At the lower end, literal model users interacted with models and manipulated model interfaces to achieve a specified goal. In the middle, Model Technicians used computational models to solve real-world problems. At the upper end, principle-based model users used computational thinking processes and principles related to systems modeling and hydrology to explain how the models worked to predict water flow. Differences between performances of literal model users, model technicians, and principle-based model users reflected shifts in how students made sense of the systems and system models crosscutting concept. These shifts in performances aligned with progress in computational thinking practices and finally with use of hydrology disciplinary core ideas. These findings contribute to understanding of how science and engineering practices, disciplinary core ideas, and crosscutting concepts intertwine during learning; how computational thinking practices develop; and how computational thinking about system models facilitates learning for environmental science literacy.

Ecosystem science and the systems ecology paradigm co-evolved starting in the late 1960s within the milieu of substantial research funding from the US National Science Foundation-supported US International Biological Program (IBP). Nationally, educational programs focusing on ecosystem structure and functioning, and mathematical modeling, were slow to develop except at Colorado State University (CSU). There, leaders in the Natural Resource Ecology Laboratory (NREL) and the Department of Range Science (DRS) established internationally recognized interdisciplinary programs and outreach in basic and applied ecosystem science and systems ecology. Operating from the sound research base within a major Land Grant University (CSU), the NREL, with IBP funding, supported many graduate students housed in the academic DRS. As the systems ecology approach expanded, other ecosystem-focused research programs developed, and graduate students entered other academic departments. Outgrowths from the early diffused educational training were innovative cross-departmental and cross-college programs addressing the systems ecology paradigm. Recently, a new Department of Ecosystem Science and Sustainability was established housing both graduate and undergraduate programs. As formal academic training developed on-campus, environmental literacy efforts were developed, including: training programs for K-12 students and teachers; online distance education programs; Citizen Science training; and numerous institutes, short courses, and workshops.

This paper reflects on the legacy of the Ambio papers by Sombroek et al. (1993), Turner et al. (1994), and Brussaard et al. (1997) on the study of agricultural land use and its impacts on global carbon storage and nutrient dynamics. The papers were published at a time of transition in ecology that involved the integration of humans as components of ecosystems, the formulation of the ecosystem services, and emergence of sustainability science. The papers offered new frameworks to studying agricultural land use across multiple scales in a way that captured causality from interacting components of the system. Each paper argued for more comprehensive data sets; foreseeing the power of network-based science, the potential of molecular technologies to assess biodiversity, and advances in remote sensing. The papers have contributed both conceptual framings and methodological approaches to an ongoing movement to identify a pathway to study agricultural land use and environmental change that fit within the concepts of ecosystem services, planetary boundaries and sustainable development goals.

The problems of today cannot be solved by the level of thinking that caused them.

The attributes and influencers that have allowed of the Natural Resource Ecology Laboratory (NREL) to exist and thrive for over five decades are described in this chapter. The chapter has two primary goals: (1) record lessons learned so other institutions wanting to establish or reinvigorate research organizations can glean ideas to help them avoid some of the pitfalls that will inevitably arise in their development, and (2) inform scientists, young and older, that when doing research using the systems ecology paradigm they do not work in organizational isolation. They stand on the shoulders of those who came before them and they depend on those around them to hold them up. Measures of success needed to be competitive, gain extramural funding support, and thrive are within organizational scientific leadership; teamwork; collaborative research; organizational pride; institutional and external influencer support; administrative functions sharing; and within-institution détente. A narrative by an organizational/industrial psychologist, who over a span of more than 25 years consulted with NREL staff on matters ranging from strategic planning and organizational management to interpersonal conflicts is presented. For developing organizations and existing organizations needing reinvigoration, ignoring his observations and insights about organizational behavior will be done at their own peril.

There is broad belief that preparing all students in preK-12 for a future in STEM involves integrating computational thinking (CT) tools and practices. Through creating and examining rich “STEM+CT” learning environments, researchers are defining what CT means in STEM disciplinary settings. This interactive session brings together a diverse spectrum of leading STEM researchers to share how they operationalize CT, what integrated CT and STEM learning looks like in their curriculum, and how this learning is measured. It will serve as a rich opportunity for discussion to help advance the state of the field of STEM and CT integration. Motivation and objectives Few argue with the need for integrating computing and computational thinking (CT) as a tool to drive innovation in STEM. The learning sciences community also acknowledges that K-12 STEM learning must become more authentic in the 21st century through the integration of coding and CT. Efforts for “STEM+CT” learning in the US received a fillip with CT listed as a disciplinary practice in the Next Generation Science Standards (NGSS; NGSS Lead States, 2013) and modeling emphasized in the NGSS and Common Core Mathematics Standards as a means to critically interrogate phenomena and understand simplifying assumptions. Although past efforts provide exemplars for the productive integration of math and science with computing (diSessa, 2001; Papert, 1980), developing integrated STEM+CT curricula and measuring such learning is seen as challenging, in part because the broader community does not have a unified definition of CT (Grover & Pea, 2013). There is thus a ICLS 2020 Proceedings 1479 © ISLS need to better understand how to achieve productive integration and learning of STEM and CT, how to best involve STEM teachers, and how to assess learning in such integrated contexts. The current landscape of STEM & computing/CT education affords ideal opportunities to convene leading researchers in the field to critically discuss current approaches for integrating STEM & CT. This symposium brings together researchers with a diverse set of approaches tackling this challenge head-on, from a variety of perspectives and pedagogical strategies at all levels of PK-12. In particular, symposium presenters will provide curricular details, examples, and insights into 1) how they operationalize CT, what CT definitions and frameworks guide their work, and how the integration of disciplinary STEM ideas with CT is engendered in their research and curricular approaches; and 2) the methods and measures they use to evaluate changes in students’ STEM & CT learning. Themes include: computational modeling in science and math (Grover et al.; Dickes, Farris & Sengupta; Metcalf et al.); co-design with teachers to modify STEM curricula to integrate CT (Irgens et al., Dominguez et al., Yadav et al.) and designing teacher PD (Lee et al.); CT and systems thinking to understand complex phenomena (Covitt et al., Damelin et al.); and design activities that integrate CT & STEM (Puttick et al.). The symposium serves to showcase similarities in CT operationalization and assessment, curricular approaches (such as modeling), and methods for design and implementation (e.g., co-design with teachers) while also highlighting the diversity of perspectives that comprise a growing landscape of PK-12 STEM+CT integration.

The aim of this chapter is to provide a synthesis of the findings from terrestrial warming experiments conducted in the Arctic and Antarctic. The Arctic is warming at twice the average global rate (Anisimov et al., 2007). The strongest warming rates worldwide occur in Siberia, northwestern Canada, and Alaska, and in the Antarctic, most notably the western Antarctic Peninsula. These systems are essentially the canaries of the coalmine, not only experiencing the strongest warming rates, but also being particularly sensitive to warming because of the limitation of many biological processes by low temperatures. First, we describe how terrestrial ecosystems in high-latitude biomes differ from ecosystems elsewhere. Then we examine experimental warming effects in the Arctic, with a focus on nonforested tundra landscapes. Next, we describe experimental warming methods and their challenges. We then review plant responses to warming, such as plant productivity and plant community dynamics to warming, and how these relate to soil nutrient availability. We transition to belowground responses of warming, including warming effects on the soil food web in the active layer (ground that thaws seasonally) of the soil profile. In the final portion of the Arctic section we discuss the implications of warming on the vast and vulnerable carbon stores in permafrost. We discuss the scale of the permafrost feedback to the global carbon balance using experimental data from Eight Mile Lake, Alaska, United States, with suggestions for improved quantification of temporal changes of carbon stores in permafrost. In the next part of the chapter we focus on Antarctica. We describe climatic and biological differences between the two principal regions on the Antarctic continent that contain field-warming experiments: the western Antarctic Peninsula and the McMurdo Dry Valleys, the largest ice-free area on the continent. We then describe the effect of warming in these two areas. In the final section of the chapter we draw parallels, but also describe differences, between the warming responses of the polar regions of both hemispheres. Taking into account the similarities and differences in responses to warming, as well as environmental and biological constraints, we then predict ecosystem trajectories under future warming scenarios for the Arctic and Antarctic. We conclude the section by synthesizing how changes in carbon cycling in the polar regions will feed back to the pace of planetary warming.

We designed two NGSS-aligned middle school classroom experiments to investigate the effects of biochar on plant growth and soil respiration. Biochar is a carbon-rich material, produced by heating organic matter under limited oxygen, that is added to soils to improve fertility, to promote plant growth, and as one possible strategy to help mitigate climate change. The experiments offer an ideal case study for students learning fundamentals of soil and plant interactions. Soils and biochar are accessible, are connected to global issues such as agriculture and climate change, and are the focus of ongoing research in soil science. These classroom experiments promote authentic science because students design replicated experiments, collect and analyze data, discuss variability in the data, and interpret their results in the context of recent research.

This article provides a validation framework for research on the development and use of science Learning Progressions (LPs). The framework describes how evidence from various sources can be used to establish an interpretive argument and a validity argument at five stages of LP research-development, scoring, generalisation, extrapolation, and use. The interpretation argument contains the interpretation (i.e. the LP and conclusions about students' proficiency generated based on the LP) and the use of the LP. The validity argument specifies how the evidence from various sources supports the interpretation and the use of the LP. Examples from our prior and current research are used to illustrate the validation activities and analyses that can be conducted at each of the five stages. When conducting an LP study, researchers may use one or more validation activities or analyses that are theoretically necessary and practically applicable in their specific research contexts.

Nitrogen deposition from anthropogenic sources is a global problem that reaches even the most remote ecosystems. Responses belowground vary by ecosystem, and have feedbacks to geochemical processes, including carbon storage. A long-term nitrogen addition study in a subalpine forest has shown carbon loss over time, atypical for a forest ecosystem. Loss of microbial biomass is likely linked to lower soil carbon, but the mechanism behind this is still unknown. One possible explanation is through increased turnover due to grazing by soil fauna. Because nematodes occupy many trophic levels and are sensitive to trophic and environmental changes, assessing their communities helps reveal belowground responses. In this study, we tested the hypothesis that long-term nitrogen fertilization affects nematode community structure and maturity beneath coniferous forests in the Rocky Mountains, indicating a faster cycling, bacterial-driven system. We identified and enumerated nematodes by trophic group and family from experimental plots. Total nematode abundance was 40–96% greater in fertilized plots compared to the control, but richness, diversity, and ecological maturity were lower. The differences in abundance were driven by opportunistic bacterivores (e.g., Rhabditidae) and plant parasites (e.g., Tylenchidae), which made up 23 and 13% of the community in fertilized compared to 7 and 5% in control plots, respectively. Nematode maturity indices showed that the nematode food web was enriched (indicating high nutrient/resource status) and structured (all trophic levels present, including long-lived predators) in both treatments, but significantly more enriched in the fertilized treatment. Nonmetric multidimensional scaling of the relative abundance of nematode families demonstrated that nematode community composition differed between treatments, driven largely by opportunistic bacterivores (e.g., Rhabditidae) in the fertilized plots. The mechanism of the aboveground–belowground link between nitrogen deposition and nematode community composition is likely through increased microbial turnover, and sustained high-quality food for microbial grazing nematodes.

This chapter focuses on the results of field and laboratory studies on the effects of paraquat and atrazine on soil arthropods. Springtails were subjected to diets in the laboratory that approximated field doses for paraquat and atrazine. In 1975 Chevron Chemical Company published a bulletin entitled, "Getting Started with No-till." In it, practical advice for using paraquat in no-tillage farming is presented. Starting on the day of hatching, individuals were fed yeast impregnated with either paraquat or atrazine. In the field, the standard concentrations are 600 mg/kg for paraquat and 500 mg/kg for atrazine. In cultures with 5000 mg/kg paraquat or atrazine, the individuals were smaller than in either of the controls or the other two concentrations. These results were obtained by continuous exposure to paraquat or atrazine after hatching. In no-tillage systems the role of the soil arthropods largely focuses on litter reduction. They feed upon microorganisms growing on the litter substrate.