Elena Sparrow

Long-term tillage and crop residue management in the subarctic: fluxes of methane and nitrous oxide

Methane and nitrous oxide are important radiatively active gases that are influenced by agricultural practices. This study assesses long-term tillage, crop residue management, and N fertilization rates on the flux of these two gases at a high latitude site representing the northern fringe of large-scale agriculture. Cumulative methane uptake for the summer was higher from no-tillage plots than tilled plots. This was associated with lower soil water contents with tillage. Thus, the reduction in CH4 uptake was attributed to water stress on methane oxidizers. At planting, soil water contents were near field capacity, and the no-till plots had the lowest uptake which was attributed to restricted diffusion of methane to active sites. A similar pattern of methane uptake to soil water content was found with the residue management treatments. Removing the straw lowered the soil water content and for most of the season methane uptake was also lower than where the straw had been left on the plots. Nitrogen fertiliz...

Decomposition in forest and fallow subarctic soils

SummaryLarge-scale argicultural development in high latitude regions could lead to large losses of soil C due to accelerated decomposition. Changes in decomposition rates of forest floor material upon land clearing in interior Alaska were simulated by measuring, over a 2-year period, changes in mass, cellulose, lignin, and N of forest floor materials and in mass of filter papers and wood in a forest floor and a fallowed field. All materials decomposed slowly at the surface, with about 90% of the original weight remaining after 2 years. Decomposition rates were higher for materials buried in the field than the forest. Cellulose loss in forest floor materials closely followed mass loss, whereas lignin loss was not significant. However, weight loss of wood was rapid when buried in the field, with about 20% of the initial mass remaining after 2 years. Relationships between mass loss of buried forest floor materials and soil degree days were significant (r=70%–80%). Temperature was a major, but not the only factor, controlling decomposition rates. Forest floor materials showed significant N losses, indicating net N mineralization and that N deficiency was not a factor affecting decomposition. C loss to the atmosphere due to decomposition of forest floor materials after forest clearing will be minimal and similar to that in the undisturbed forest if left on the soil surface, but will be substantial if incorportated into the soil. Incorporation is necessary for cropping; thus some accelerated decomposition is unavoidable in clearing subarctic forests for cultivation.

Collaboration, interdisciplinary thinking, and communication: new approaches to K–12 ecology education

Ecologists often engage in global-scale research through partnerships among scientists from many disciplines. Such research projects require collaboration, interdisciplinary thinking, and strong communication skills. We advocate including these three practices as an integral part of ecology education at the kindergarten through 12th grade (K–12) level, as opposed to waiting until the graduate level. Current discourse about K–12 ecology education focuses on promoting lessons in which students learn science by conducting research rather than simply reading textbooks. Here, we present five models of K–12 ecology education programs that emphasize collaboration, interdisciplinary thinking, and communication within student research projects on the ecology of drylands and other ecosystems. Such practices not only provide additional skills for future ecologists but also prepare students for success in any career as well as for ecologically literate citizenship.

Education, outreach and communication during the International Polar Year 2007–2008: stimulating a global polar community

The International Polar Year 2007–2008 (IPY) represented one of the largest international scientific research efforts ever undertaken. In addition to its goals of making major advances in polar knowledge, stimulating new and enhanced observational systems and infrastructure, and inspiring a new generation of polar scientists and engineers, it also stimulated the active engagement of thousands of teachers, students and citizens around the world through careful cultivation of enthusiastic scientists, educators and communicators and through creative use of free technologies. The establishment of this new “global polar community” resulted from a deliberate effort to stimulate a sense of polar affinity that extended beyond the relatively select group of people who live, work or visit these regions. This paper describes and assesses those community-building efforts, including international coordination of events, activities and materials, science and education partnerships, and professional recognition for outreach activities.

Phosphorus and nitrogen dynamics during field incubations in forest and fallow subarctic soils

A knowledge of the nutrient dynamics that occur with land use changes, e.g., in clearing forests for farmland, is useful in choosing the most efficient soil and fertilizer management practices. To determine net in situ P and N mineralization and nitrification rates of forest floor materials and their nutrient value for agricultural crops, plastic bags containing different materials (moss, O horizon, and A horizon) collected from a subarctic black spruce (Picea mariana Mill.) forest were incubated for 2 years in their respective forest horizons and at 7.5 cm depth in a nearby fallow field. Net amounts of P and N mineralized were highest in moss and were similar in forest and field when the temperature and moisture content were similar, but smaller in forest when the water content was higher. Net nitrification was negligible in O and A horizon material but significant in moss during the 2nd year, occurring sooner and producing higher NOinf3sup-levels in the field (171 mg ha-1) than in the forest (13 mg ha-1). Moss P and N mineralization rates were correlated in the fallow field. Temperature, moisture content, and substrate quality were important factors controlling P and N dynamics of forest floor materials in a subarctic fallow field and native forest. In subarctic regions, incorporation and mineralization of forest floor materials could provide an early source of N and P (70 and 17 kg ha-1, respectively) for succeeding agricultural crops.

Strategies for teaching to a changing world: lessons from Arusha, Tanzania

Environmental degradation, lack of educational resources and extreme poverty characterize many countries in Africa. These issues require teachers to prepare students to understand, address and solve these and other challenges facing societies in the twenty-first century. Using the environment as an authentic and integrating context, a team of scientists and educators developed a teacher professional development workshop model that actively engages teachers in the science process while learning science content and research techniques. Over 50 primary and secondary school teachers from three countries in Africa attended the workshop which was convened in Arusha, Tanzania. Although the workshop team included members from Africa, most were from the United States with varied experience working in Africa. The team viewed this workshop as an opportunity to assess the process of workshop model development and implementation in order to glean lessons that could then be applied to other professional development opportunities in Africa. To help assess the process, internal organizing discussions, participant surveys and teacher focus group discussions were used. Results from the surveys and discussions indicate that the workshop had a positive impact on the teachers and instructors suggesting that workshop materials and pedagogical approaches have a high probability of being implemented in African classrooms.

Evapotranspiration Cycles in a High Latitude Agroecosystem: Potential Warming Role.

As the acreages of agricultural lands increase, changes in surface energetics and evapotranspiration (ET) rates may arise consequently affecting regional climate regimes. The objective of this study was to evaluate summertime ET dynamics and surface energy processes in a subarctic agricultural farm in Interior Alaska. The study includes micrometeorological and hydrological data. Results covering the period from June to September 2012 and 2013 indicated consistent energy fractions: LE/R net (67%), G/R net (6%), H/R net (27%) where LE is latent heat flux, R net is the surface net radiation, G is ground heat flux and H is the sensible heat flux. Additionally actual surface evapotranspiration from potential evaporation was found to be in the range of 59 to 66%. After comparing these rates with those of most prominent high latitude ecosystems it is argued here that if agroecosystem in high latitudes become an emerging feature in the land-use, the regional surface energy balance will significantly shift in comparison to existing Arctic natural ecosystems.

Engaging Alaska Communities and Students in Cryospheric Research

This community-based Permafrost/Active Layer Monitoring (PALM) Program is greatly successful from both educational and scientific viewpoints. The Permafrost/Active Layer Monitoring Program is an ongoing project that builds on work begun in 2005 to establish long-term permafrost and active layer monitoring sites adjacent to schools in Alaska and in the circumpolar permafrost region. Monitoring stations are located all over Alaska, including the Aleutians, the Bering Sea Islands, and southeast Alaska. Two hundred schools in Alaska are involved in the project, and a monitoring site has been included at Denali National Park and Kenai Fjord National Park. The monitoring sites collect temperature measurement data on permafrost and the length and depth of the active layer (the layer above the permafrost that thaws during summer and freezes again during winter). This information is important because changes in permafrost conditions affect local ecosystems and hydrological regimes and can influence the severity of natural disasters. In addition to extending our knowledge of the environment of the cryosphere, the program involves school-age students in hopes of inspiring a new generation of scientists to continue this study.

Integrating Geoscience Research in Primary and Secondary Education

The Monitoring Seasons Through Global Learning Communities project, also known as Seasons and Biomes, engages primary and secondary students in earth system and environmental science research in the learning of science in schools. The overall goal of this inquiry- and project-based International Polar Year (IPY) project is to increase precollege students’ understanding of the earth system. This project brings together students, educators, communities, and scientists in locally and globally relevant studies and provides opportunities for students to participate in IPY activities during and beyond the fourth IPY and to contribute to earth science studies. Seasons and Biomes primary approach is through teacher professional development (PD) workshops. We developed a PD workshop model that combines earth system science content, measurement protocols, a student scientific investigation model, and best teaching practices. We conducted regional, national, and international PD workshops for educators and scientists who in turn teach their students and/or train other teachers/trainers. More than 1,400 teachers and trainers in 50 countries have participated in Seasons and Biomes PD workshops, reaching more than 21,000 students. Students also participated in global learning community projects such as Pole-to-Pole Videoconferences, the Ice e-Mystery Polar e-Book project, GS-Pals (school to school across countries, web-based discussions and collaborations facilitated by GLOBE Alumni), and Mt. Kilimanjaro expeditions (mountain trek and virtual journey). Integrating geoscience research in precollege schools has resulted in numerous student research projects as well as data contributions to ongoing studies of the earth system. Additionally, project evaluation results and evidence submitted by teachers on student learning suggest high program implementation and understanding of earth system science and the science process.