Ethical issues involving long-term land leases: a soil sciences perspective

As populations grow and arable land becomes increasingly scarce, large-scale long- term land leases are signed at a growing rate. Countries and investors with large amounts of financial resources and a strong agricultural industry seek long-term land leases for agricultural exploitation or investment purposes. Leaders of financially poorer countries often advertise such deals as a fast way to attract foreign capital. Much has been said about the short-term social costs these types of leases involve, however, less has been said about the normative dimension of their long-term environmental impact. We therefore will focus on the likely impact such deals have for soil conservation, by (1) briefly introducing the basics of long-term leasing arrangements by comparing land leases to the renting of buildings, (2) explaining from a soil sciences perspective the difficulties in assessing the current value of an estate and in calculating the damages of soil erosion and degradation, and (3) show how difficult it is to incentivize the conservation of soil quality when one cannot sufficiently and cost-effectively valorize existing environmental capital and eventual future damages. Attempting to oblige tenants through contracts to invest in sustainable stewardship has limited potential when liability payments do not reflect true costs and are hard to enforce

Differential Interleukin-2 Transcription Kinetics Render Mouse but Not Human T Cells Vulnerable to Splicing Inhibition Early after Activation

T cells are nodal players in the adaptive immune response against pathogens and malignant cells. Alternative splicing plays a crucial role in T cell activation, which is analyzed mainly at later time points upon stimulation. Here we have discovered a 2-h time window early after stimulation where optimal splicing efficiency or, more generally, gene expression efficiency is crucial for successful T cell activation. Reducing the splicing efficiency at 4 to 6 h poststimulation significantly impaired murine T cell activation, which was dependent on the expression dynamics of the Egr1-Nab2-interleukin-2 (IL-2) pathway. This time window overlaps the time of peak IL-2 de novo transcription, which, we suggest, represents a permissive time window in which decreased splicing (or transcription) efficiency reduces mature IL-2 production, thereby hampering murine T cell activation. Notably, the distinct expression kinetics of the Egr1-Nab2-IL-2 pathway between mouse and human render human T cells refractory to this vulnerability. We propose that the rational temporal modulation of splicing or transcription during peak de novo expression of key effectors can be used to fine-tune stimulation-dependent biological outcomes. Our data also show that critical consideration is required when extrapolating mouse data to the human system in basic and translational research

Ground-based detection of a vibration-rotation line of HD in Orion

The v =1-0 R(5) line of HD at 2.46um has been detected at the position of brightest line emission of shocked H2 in the Orion Molecular Cloud. The flux in this HD line, when compared to that of the previously detected HD 0--0 R(5) line at 19.43um, suggests that, like the v=1 levels of H2, the v=1 levels of HD are populated in LTE, despite their much higher rates of spontaneous emission compared to H2. The higher than expected population of vibrationally excited HD may be due to chemical coupling of HD to H2 via the reactive collisions HD + H H2 + D in the shocked gas. The deuterium abundance implied by the strengths of these lines relative to those of H2 is (5.1 pm 1.9 x 10^-6.Comment: 9 pages, 2 figures, Proceedings of the Conference on "Deuterium in the Universe," to be published in Planetary and Space Science

Agro-ecology: beyond food

Some may view indigenous communities as being conservative and backwards. However, the Kabekwa in Costa Rica show that such communities can be adaptable and innovative. In response to changing circumstances, this community has been adapting its farming practices constantly, benefiting from it in multiple ways. In this case study we show some of the additional advantages agro-ecology provides to farmers beside food. Using the concept of meaningful work we explore how knowledge-intensive farming stimulates the development of skills, improves self-determination and provides incentives for younger generations to work on the land

Adapting Food Production to Climate Change: An Inclusive Approach

On why agricultural innovation from the Global South can and should be used to adapt food production to climate change. Discussed on hand of three cases studie

Biophysical feedbacks in the tropical Pacific

This study explores the influence of phytoplankton on the tropical Pacific heat budget. A hybrid coupled model for the tropical Pacific that is based on a primitive equation reduced-gravity multilayer ocean model, a dynamic ocean mixed layer, an atmospheric mixed layer, and a statistical atmosphere is used. The statistical atmosphere relates deviations of the sea surface temperature from its mean to wind stress anomalies and allows for the rectification of the annual cycle and the El Niño–Southern Oscillation (ENSO) phenomenon through the positive Bjerknes feedback. Furthermore, a nine-component ecosystem model is coupled to the physical variables of the ocean. The simulated chlorophyll concentrations can feed back onto the ocean heat budget by their optical properties, which modify solar light absorption in the surface layers. It is shown that both the surface layer concentration as well as the vertical profile of chlorophyll have a significant effect on the simulated mean state, the tropical annual cycle, and ENSO. This study supports a previously suggested hypothesis (Timmermann and Jin) that predicts an influence of phytoplankton concentration of the tropical Pacific climate mean state and its variability. The bioclimate feedback diagnosed here works as follows: Maxima in the subsurface chlorophyll concentrations lead to an enhanced subsurface warming due to the absorption of photosynthetically available shortwave radiation. This warming triggers a deepening of the mixed layer in the eastern equatorial Pacific and eventually a reduction of the surface ocean currents (Murtugudde et al.). The weakened south-equatorial current generates an eastern Pacific surface warming, which is strongly enhanced by the Bjerknes feedback. Because of the deepening of the mixed layer, the strength of the simulated annual cycle is also diminished. This in turn leads to an increase in ENSO variability

Effects of salt compensation on the climate model response in simulations of large changes of the Atlantic meridional overturning circulation

Freshwater hosing experiments with a comprehensive coupled climate model and a coupled model of intermediate complexity are performed with and without global salt compensation in order to investigate the robustness of the bipolar seesaw. In both cases, a strong reduction of the Atlantic meridional overturning circulation is induced, and a warming in the South Atlantic results. When a globally uniform salt flux is applied at the surface in order to keep the global mean salinity constant, this causes additional widespread warming in the Southern Ocean. It is shown that this warming is mainly due to heat transport anomalies that are induced by the specific parameterization in ocean models to represent eddy mixing. Surface salt fluxes tend to move outcropping isopycnals equatorward. As the density perturbation originates at the surface, changes in isopycnal slopes are generated that lead to anomalies in the bolus velocity field. The associated bolus heat flux convergence creates a warming enhancing the bipolar seesaw response, particularly in the Southern Ocean. The importance of this mechanism is illustrated in coupled model simulations in which this parameterization in the ocean model component is switched on or off. Additional experiments in which the same total amount of freshwater is delivered at rates 10 times smaller show that the effect of the global salt compensation is not important in this case, but that the eddy-mixing parameterization is still responsible for a substantial temperature response in the Southern Ocean

The Effect of Flow at Maud Rise on the Sea Ice Cover - Numerical Experiments

The role of seamounts in the formation and evolution of sea ice isinvestigated in a series of numerical experiments with a coupled seaice-ocean model. Bottom topography, stratification and forcing areconfigured for the Maud Rise region in the Weddell Sea. The specificflow regime that develops at the seamount as the combined response tosteady and tidal forcing consists of free and trapped waves and aTaylor column, which is caused by mean flow and tidal flowrectification. The enhanced variability through tidal motion inparticular is capable of modifying the mixed layer above the seamountenough to delay and reduce sea ice formation throughout the winter.The induced sea ice anomaly spreads and moves westward and affects anarea of several 100~000 km$^{2}$. Process studies reveal the complexinteraction between wind, steady and periodic ocean currents: allthree are required in the process of generation of the sea ice andmixed layer anomalies (mainly through tidal flow), their detachmentfrom the topography (caused by steady oceanic flow), and the westwardtranslation of the sea ice anomaly (driven by the time-mean wind)

Phytoplankton influences on tropical climate

We study the effect of ocean biology on tropical surface temperatures using a simplified coupled atmosphere-ocean model. It is shown that moderate phytoplankton blooms, occuring e.g. during La Niña conditions, lead to a vertical redistribution of heat in the surface layers and an associated surface layer warming of about 20 W/m2. The positive air-sea coupling in the eastern equatorial Pacific plays an important role in amplyfying this signal, thereby damping La Niña conditions. This temperature-regulating feedback acts as a biological thermostat within the surface ocean and influences also the amplitude and asymmetry of the El Niño-Southern Oscillation