Achieving urban food and nutrition security in the developing world:

CONTENTS: Brief 1. Overview / James L. Garrett Brief 2. An urbanizing world / Martin Brockerhoff Brief 3. Rural-urban interdependence / Ceclia Tacoli Brief 4. Urban livelihoods and labor markets / Arjan de Haan Brief 5. Feeding the cities: food supply and distribution / Olivio Argenti Brief 6. The hidden significance of urban agriculture / Luc J.A. Mougeot Brief 7. Urbanization and the nutrition transition / Barry M. Popkin Brief 8. Urban women: balancing work and childcare / Patrice L. Engle Brief 9. Threats to urban health / Carolyn Stephens Brief 10. Programming for urban food and nutrition security / Timothy R. Frankenberger, James L. Garrett, and Jeanne Downen.Food supply, food security, Livelihoods, Urban programming,

Reconstructing paleoseismic deformation, 2: 1000 years of great earthquakes at Chucalén, south central Chile

In this paper we adopt a quantitative biostratigraphic approach to establish a 1000-year-long coastal record of megathrust earthquake and tsunami occurrence in south central Chile. Our investigations focus on a site in the centre of the rupture segment of the largest instrumentally recorded earthquake, the AD 1960 magnitude 9.5 Chile earthquake. At Chucalén coseismic subsidence in 1960 is recorded in the lithostratigraphy and biostratigraphy of coastal marshes, with peat overlain by minerogenic sediment and changes in the assemblages of diatoms (unicellular algae) indicating an abrupt increase in relative sea level. In addition to the 1960 earthquake, the stratigraphy at Chucalén records three earlier earthquakes, the historically documented earthquake of 1575 and two prehistoric earthquakes, radiocarbon dated to AD 1270–1450 and 1070–1220. Laterally extensive sand sheets containing marine or brackish diatom assemblages suggest tsunami deposition associated with at least two of the three pre-1960 earthquakes. The record presented here suggests a longer earthquake recurrence interval, averaging 270 years, than the historical recurrence interval, which averages 128 years. The lack of geologic evidence at Chucalén of two historically documented earthquakes, in 1737 and 1837, supports the previously suggested hypothesis of variability in historical earthquake characteristics. Our estimates of coseismic land-level change for the four earthquakes range from meter-scale subsidence to no subsidence or slight uplift, suggesting earthquakes completing each ∼270 year cycle may not share a common, characteristic slip distribution. The presence of buried soils at elevations below their modern equivalents implies net relative sea-level rise over the course of the Chucalén paleoseismic record, in contrast to relative sea-level fall over preceding millennia inferred from sites on the mainland. Sea-level rise may contribute to the preservation of evidence for multiple earthquakes during the last millennium, while net relative sea-level fall over the last 2000–5000 years may explain the lack of evidence for older earthquakes

Origen y distribución de depósitos de tsunami en la marisma de Chaihuín (40° S/73,5° O), Chile

At Chaihuín marsh, south of Valdivia (39°56’ S/73°33’ W), a sand bed was deposited during the 1960 earthquake. The aim of this study is to map the 1960 tsunami deposit in detail and to associate earlier sand layers with past tsunamis. Geologic field mapping by means of stratigraphic sections constructed using 111 cores in the marsh revealed the existence of three sand layers. The source of these sand layers was determined by a statistical comparison of their sedimentological and mineralogical signatures with modern depositional environments. The results show that tsunami waves probably transported the sand layers found in the marsh. It is inferred that these sand layers were deposited in the marsh by tsunamis that followed subsidence associated with the great historical megathrust earthquakes of 1575, 1737 or 1837, and 1960. However, the three layers are different from each other in terms of lateral distribution and source, which we interpret as either changes in the sand bar associated with human occupation or differences in coseismic slip distribution resulting in variable accommodation space provided by coseismic subsidence as well as in tsunami wave height. En la marisma de Chaihuín, al sur de Valdivia (39°56’ S/73°33’ O), se ha preservado una capa de arena depositada por el tsunami asociado al terremoto de 1960. El presente estudio tiene como objetivo la caracterización de este depósito y de las capas de posibles tsunamis asociadas a terremotos anteriores a dicho evento. Secciones estratigráficas realizadas con base en 111 testigos dentro de la marisma revelaron la existencia de 3 capas de arena. La fuente de la arena se determinó mediante análisis estadísticos que compararon sus características sedimentológicas y mineralógicas con los ambientes de depositación modernos. Los resultados sugieren que ondas de tsunami probablemente transportaron las capas de arena que se encuentran en la marisma. Se infiere que dichas capas de arena fueron depositadas por tsunamis que siguieron a la subsidencia asociada con los grandes terremotos históricos de 1575, 1737 o 1837 y 1960. Sin embargo, las 3 capas son diferentes entre sí, en términos de distribución lateral y fuente, lo que se interpreta como producto de los cambios en la barra de arena asociada a la ocupación humana o a las diferencias en la distribución de desplazamiento cosísmico lo que produce variaciones en el espacio de acomodación por hundimiento cosísmico y en la altura de las olas del tsunami

Drivers of 20th Century Sea-Level Change in Southern New Zealand Determined from Proxy and Instrumental Records

In this paper we present new proxy-based sea-level reconstructions for southern New Zealand spanning the last millennium. These palaeo sea-level records usefully complement sparse Southern Hemisphere proxy and tide-gauge sea-level datasets and, in combination with instrumental observations, can test hypotheses about the drivers of 20th century global sea-level change, including land-based ice melt and regional sterodynamics. We develop sea-level transfer functions from regional datasets of salt-marsh foraminifera to establish a new proxy-based sea-level record at Mokomoko Inlet, at the southern tip of the South Island, and to improve the previously published sea-level reconstruction at Pounawea, located about 110 km to the east. Chronologies are based on radiocarbon, radiocaesium, stable lead isotope and pollen analyses. Both records are in good agreement and show a rapid sea-level rise in the first half of the 20th century that peaked in the 1940s. Previously reported discrepancies between proxy-based sea-level records and tide-gauge records are partially reconciled by accounting for barystatic and sterodynamic components of regional sea-level rise. We conclude that the rapid sea-level rise during the mid-20th century along the coast of southern New Zealand was primarily driven by regional thermal expansion and ocean dynamics

Saltmarsh blue carbon accumulation rates and their relationship with sea-level rise on a multi-decadal timescale in northern England

Feldwork and elemental and thermogravimetric analyses were conducted as a part of the NERC funded (NE/R010846/1) Carbon Storage in Intertidal Environments (C-SIDE) project (https://www.c-side.org/).Saltmarshes are widely thought to sequester carbon at rates significantly exceeding those found in terrestrial environments. This ability arises from the in-situ production of plant biomass and the effective trapping and storage of both autochthonous and allochthonous organic carbon. The role saltmarshes play in climate change mitigation, through accumulating ‘blue’ carbon, depends on both the rate at which carbon accumulates within sediments and the rapidity with which carbon is remineralised. It has been hypothesized that carbon accumulation rates, in turn, depend on the local rate of relative sea-level rise, with faster sea-level rise providing more accommodation space for carbon storage. This relationship has been investigated over long (millennial) and short (decadal) timescales but without accounting for the impact of higher quantities of labile carbon in more recently deposited sediment. This study addresses these three key aspects in a saltmarsh sediment study from Lindisfarne National Nature Reserve (NNR), northern England, where there is a comparatively pristine marsh. We quantify rates of carbon accumulation by combining a Bayesian age-depth model based on 210Pb and 137Cs activities with centimetre-resolution organic carbon density measurements. We also use thermogravimetric analyses to determine the relative proportions of labile and recalcitrant organic matter and calculate the net recalcitrant organic matter accumulation rate. Results indicate that during the 20th century more carbon accumulated at the Lindisfarne NNR saltmarsh during decades with relatively high rates of sea-level rise. The post-depositional loss of labile carbon down the core results in a weaker though still significant relationship between recalcitrant organic matter accumulation and sea-level change. Thus, increasing saltmarsh carbon accumulation driven by higher rates of sea-level rise is demonstrated over recent multi-decadal timescales.Peer reviewe

Geological evidence of an unreported historical Chilean tsunami reveals more frequent inundation

Assessing tsunami hazards commonly relies on historical accounts of past inundations, but such chronicles may be biased by temporal gaps due to historical circumstances. As a possible example, the lack of reports of tsunami inundation from the 1737 south-central Chile earthquake has been attributed to either civil unrest or a small tsunami due to deep fault slip below land. Here we conduct sedimentological and diatom analyses of tidal marsh sediments within the 1737 rupture area and find evidence for a locally-sourced tsunami consistent in age with this event. The evidence is a laterally-extensive sand sheet coincident with abrupt, decimetric subsidence. Coupled dislocation-tsunami models place the causative fault slip mostly offshore rather than below land. Whether associated or not with the 1737 earthquake, our findings reduce the average recurrence interval of tsunami inundation derived from historical records alone, highlighting the importance of combining geological and historical records in tsunami hazard assessment

Bioinformatics process management: information flow via a computational journal

This paper presents the Bioinformatics Computational Journal (BCJ), a framework for conducting and managing computational experiments in bioinformatics and computational biology. These experiments often involve series of computations, data searches, filters, and annotations which can benefit from a structured environment. Systems to manage computational experiments exist, ranging from libraries with standard data models to elaborate schemes to chain together input and output between applications. Yet, although such frameworks are available, their use is not widespread–ad hoc scripts are often required to bind applications together. The BCJ explores another solution to this problem through a computer based environment suitable for on-site use, which builds on the traditional laboratory notebook paradigm. It provides an intuitive, extensible paradigm designed for expressive composition of applications. Extensive features facilitate sharing data, computational methods, and entire experiments. By focusing on the bioinformatics and computational biology domain, the scope of the computational framework was narrowed, permitting us to implement a capable set of features for this domain. This report discusses the features determined critical by our system and other projects, along with design issues. We illustrate the use of our implementation of the BCJ on two domain-specific examples

Organic carbon accumulation in British saltmarshes

Funding: This research was financially supported by the Natural Environment Research Council funded Carbon Storage in Intertidal Environments (C-SIDE) project (grant NE/R010846/1) with additional support from the Scottish Blue Forum. Radiocarbon dating was supported by the National Environment Isotope Facility Radiocarbon (Environment) Laboratory (allocation 2351.0321).Saltmarshes are a crucial component of the coastal carbon (C) system and provide a natural climate regulation service through the accumulation and long-term storage of organic carbon (OC) in their soils. These coastal ecosystems are under growing pressure from a changing climate and increasing anthropogenic disturbance. To manage and protect these ecosystems for C and to allow their inclusion in emissions and natural-capital accounting, as well as carbon markets, accurate and reliable estimates of OC accumulation are required. However, globally, such data are rare or of varying quality. Here, we quantify sedimentation rates and OC densities for 21 saltmarshes in Great Britain (GB). We estimate that, on average, saltmarshes accumulate OC at a rate of 110.88 ± 43.12 g C m-2 yr-1. This is considerably less than widely applied global saltmarsh averages. It is therefore highly likely that the contribution of northern European saltmarshes to global saltmarsh OC accumulation has been significantly overestimated. Taking account of the climatic, geomorphological, oceanographic, and ecological characteristics of all GB saltmarshes and the areal extent of different saltmarsh zones, we estimate that the 451.65 km2 of GB saltmarsh accumulates 46,563 ± 4,353 tonnes of OC annually. These low OC accumulation rates underline the importance of the 5.20 ± 0.65 million tonnes of OC already stored in these vulnerable coastal ecosystems. Going forward the protection and preservation of the existing stores of OC in GB saltmarshes must be a priority for the UK as this will provide climate benefits through avoided emissions several times more significant than the annual accumulation of OC in these ecosystems.Peer reviewe

RESOLVING UNCERTAINTIES IN FORAMINIFERA-BASED RELATIVE SEA-LEVEL RECONSTRUCTION : A CASE STUDY FROM SOUTHERN NEW ZEALAND

Since the pioneering work of David Scott and others in the 1970s and 1980s, foraminifera have been used to develop precise sea-level reconstructions from salt marshes around the world. In New Zealand, reconstructions feature rapid rates of sea-level rise during the early to mid-20th century. Here, we test whether infaunality, taphonomy, and sediment compaction influence these reconstructions. We find that surface (0–1 cm) and subsurface (3–4 cm) foraminiferal assemblages show a high degree of similarity. A landward shift in assemblage zones is consistent with recent sea-level rise and transgression. Changes associated with infaunality and taphonomy do not affect transfer function-based sea-level reconstructions. Applying a geotechnical modelling approach to the core from which sea-level changes were reconstructed, we demonstrate compaction is also negligible, resulting in maximum post-depositional lowering of 2.5 mm. We conclude that salt-marsh foraminifera are indeed highly accurate and precise indicators of past sea levels