Warmer and drier climates over Amazonia have been predicted for the next century with expected changes in regional water and carbon cycles. We examined the impact of interannual and seasonal variations in climate conditions on ecosystem-level evapotranspiration (ET) and water use efficiency (WUE) to determine key climatic drivers and anticipate the response of these ecosystems to climate change. We used daily climate and eddyflux data recorded at the Guyaflux site in French Guiana from 2004 to 2014. ET and WUE exhibited weak interannual variability. The main climatic driver of ET and WUE was global radiation (Rg), but relative extractable water (REW) and soil temperature (Ts) did also contribute. At the seasonal scale, ET and WUE showed a modal pattern driven by Rg, with maximum values for ET in July and August and for WUE at the beginning of the year. By removing radiation effects during water depleted periods, we showed that soil water stress strongly reduced ET. In contrast, drought conditions enhanced radiation-normalized WUE in almost all the years, suggesting that the lack of soil water had a more severe effect on ecosystem evapotranspiration than on photosynthesis. Our results are of major concern for tropical ecosystem modeling because they suggest that under future climate conditions, tropical forest ecosystems will be able to simultaneously adjust CO₂ and H₂O fluxes. Yet, for tropical forests under future conditions, the direction of change in WUE at the ecosystem scale is hard to predict, since the impact of radiation on WUE is counterbalanced by adjustments to soil water limitations. Developing mechanistic models that fully integrate the processes associated with CO₂ and H₂O flux control should help researchers understand and simulate future functional adjustments in these ecosystems.

The coronavirus pandemic (COVID-19) is a global health crisis that has affected educational systems worldwide. North Eastern Mindanao State University (NEMSU), a typical countryside academic institution in the Southern Philippines, did not escape this dilemma. The advent of remote learning to continue the students’ learning process has caused difficulties for both the students and the educational institutions. Thus, we conducted this study to assess the students’ level of submission of assigned tasks from printed remote learning modular materials under the College of Teacher Education of NEMSU. We evaluated whether the distance of students’ residences to the campus or the nearest online learning facilities affects the level of modular task retrievals. We also determined the current situation, challenges, and struggles of the students with remote learning. Our results showed that out of 392 printed learning modules sent to Bachelor of Elementary Education (BEED) students, 299 or 76% were retrieved. There were also 292 Bachelor of Secondary Education (BSED) students who received the learning modules, and 237, or 81%, complied with their tasks. We found that 68% of the total number of students reside within a <30 km radius, while 32% were within a 30–40 km radius. We also found that the distance of their residences from the NEMSU campus slightly affected the percentage of modular learning material retrievals for both the BEED and BSED students, with R² = 0.38 and R² = 0.07, respectively. Nonstructured interview results showed that most students were constrained by many challenges and struggles in complying with the tasks. These include internet connectivity problems, inadequate learning resources, difficulty understanding the module contents and assessment instructions, overloaded remote learning tasks, poor learning environment, and mental health problems. This study also revealed that the country’s digital divide became more apparent as we navigated this new mode of the remote learning system.

We conducted a soil warming experiment in a cool-temperate forested peatland in northern Japan during the snow-free seasons of 2007–2011, to determine whether the soil warming would change the heterotrophic respiration rate and its temperature sensitivity. We elevated the soil temperature by 3°C at 5-cm depth by using overhead infrared heaters and continuously measured hourly soil CO2 fluxes with a 15-channel automated chamber system. The 15 chambers were divided into three groups each with five replications for the control, unwarmed-trenched and warmed-trenched treatments. Soil warming enhanced heterotrophic respiration by 82% (mean of four seasons (2008–2011) observation±SD, 6.84±2.22 µmol C m−2 s−1) as compared to the unwarmed-trenched treatment (3.76±0.98 µmol C m−2 s−1). The sustained enhancement of heterotrophic respiration with soil warming suggests that global warming will accelerate the loss of carbon substantially more from forested peatlands than from other upland forest soils. Soil warming lik...