East pacific rise: hot springs and geophysical experiments

Hydrothermal vents jetting out water at 380 degrees +/- 30 degrees C have been discovered on the axis of the East Pacific Rise. The hottest waters issue from mineralized chimneys and are blackened by sulfide precipitates. These hydrothermal springs are the sites of actively forming massive sulfide mineral deposits. Cooler springs are clear to milky and support exotic benthic communities of giant tube worms, clams, and crabs similar to those found at the Galápagos spreading center. Four prototype geophysical experiments were successfully conducted in and near the vent area: seismic refraction measurements with both source (thumper) and receivers on the sea floor, on-bottom gravity measurements, in situ magnetic gradiometer measurements from the submersible Alvin over a sea-floor magnetic reversal boundary, and an active electrical sounding experiment. These high-resolution determinations of crustal properties along the spreading center were made to gain knowledge of the source of new oceanic crust and marine magnetic anomalies, the nature of the axial magma chamber, and the depth of hydrothermal circulation.     

Late Pleistocene Desiccation of Lake Victoria and Rapid Evolution of Cichlid Fishes

Lake Victoria is the largest lake in Africa and harbors more than 300 endemic species of haplochromine cichlid fish. Seismic reflection profiles and piston cores show that the lake not only was at a low stand but dried up completely during the Late Pleistocene, before 12,400 carbon-14 years before the present. These results imply that the rate of speciation of cichlid fish in this tropical lake has been extremely rapid.     

Soil microbial inoculants for sustainable agriculture: Limitations and opportunities

The burgeoning global market for soil microbial inoculants for use in agriculture is being driven by pressure to increase sustainable crop production by managing pests and diseases without environmental impacts. Microbial inoculants, based predominantly on bacteria and fungi, are applied to soil as alternatives to conventional inorganic fertilizers (biofertilizers) or to carry out specific functions including biocontrol of pests and diseases (biopesticides), or for bioremediation and enhancement of soil characteristics. While some soil inoculants such as rhizobia have a long and successful history of use, others have performed inconsistently in the field and failed to live up to their promise suggested by laboratory testing. A more precise understanding of the ecology and modes of action of inoculant strains is key to optimizing their efficacy and guiding their targeted use to situations where they address key limitations to crop production. This will require greater collaboration between science disciplines, including microbiology, plant and soil science, molecular biology and agronomy. Inoculants must be produced and formulated to ensure their effective establishment in the soil and practicality of implementation alongside existing cropping practices. New approaches to strain selection and construction of beneficial microbial consortia should lead to more efficacious inoculant products. Extensive and rigorous field evaluation of inoculants under a range of soil and environmental conditions has rarely been undertaken and is urgently needed to validate emerging inoculant products and underpin successful implementation by growers, especially in a market that is largely unregulated at present.     

Seeing below the surface: making soil processes visible to Ugandan smallholder farmers through a constructivist and experiential extension approach

Ugandan smallholder farmers need to feed a growing population, but their efforts are hampered by declining soil fertility rates. Agricultural extension can facilitate farmers’ access to new practices and technologies, yet farmers are understandably often hesitant to adopt new behaviors. New knowledge assimilation is an important component of behavior change that is often overlooked or poorly addressed by current extension efforts. We implemented a Fertility Management Education Program (FMEP) in central Uganda to investigate smallholder farmers’ existing soil knowledge and their assimilation of new scientific concepts into their knowledge framework. Qualitative data were collected through participant observation, farmer interviews, and focus groups, and coded for using a priori and emergent themes. Our exploration revealed some notable similarities between farmers’ soil knowledge and scientific concepts, particularly in regards to soil health concepts, a discovery that could facilitate communication between extension agents and farmers. However, certain scientific concepts are either unknown to farmers or discordant with existing soil knowledge; these concepts are unlikely to be assimilated by farmers without convincing and concerted extension efforts. Importantly, we found that the combination of new scientific knowledge and hands-on experimentation with novel practices gave farmers far greater confidence in implementing improved soil management practices. Our study provides evidence that extension programs should engage directly with farmers’ existing soil knowledge to develop their understanding of key biological concepts and confidence in implementing improved practices.