The informal Australian city

In recent years, a vibrant literature on urban informality has emerged in urban geography. A key claim of this literature is that informality is not only present in cities in the Global South, and that the concept can be usefully applied to understand important dimensions of urbanisation in cities in the Global North. In this paper, we apply insights from that literature to an examination of informality in Australian cities, as a means of deepening our understanding of changes currently underway in urban governance and politics. Drawing on that literature and our own research into informal practices in Australian cities, we examine the forces that help to produce informality, the diverse forms and agents of informality, the forms of authority that they enact, and their relationship to formal economies, regulations and politics. We use examples of informal housing, informal labour, do-it-yourself music venues, graffiti and its regulation, food foraging, and queer community building in Sydney to illustrate our arguments. We conclude by reflecting on the lessons learnt across these diverse cases for our understanding of urban governance and politics in Australia, and offer an agenda for further research on this issue.     

Relationship between heavy metal accumulation and genetic variability decrease in the intertidal crab Pachygrapsus marmoratus (Decapoda; Grapsidae)

The “genetic erosion” hypothesis posits that heavy metal stress is related to a loss of genetic diversity at the population level. The genetic diversity of natural populations can, however, be affected by natural processes as well as by human impact. We studied the relationship between heavy metal bioaccumulation and genetic variability in the intertidal crab Pachygrapsus marmoratus. Tissue samples were collected from 40 individuals inhabiting four polluted and four unpolluted sites along the Tuscan coast (Mediterranean basin), and were examined for four heavy metals (arsenic, As, cadmium, Cd, lead, Pb, and copper, Cu). We also assessed the genetic variability of 235 crabs from the same localities using six microsatellite loci.Our results show that the bioaccumulation levels of these individuals accurately reflect the levels of pollution in their immediate environment, and that heavy metals accumulate more in the hepatopancreas than in the gills. Moreover, populations from polluted sites have significantly less genetic variability, measured as mean standardized d², and a significantly lower percentage of unrelated individuals, than populations from unpolluted sites. This evidence supports the “genetic erosion” hypothesis for metal heavy exposure in natural environments.     

Vertical migrations of the mangrove snail Cerithidea decollata (L.) (Potamididae) through a synodic month

The vertical migration on mangrove trunks of the gastropod Cerithidea decollata was followed for 5 weeks, in a Kenyan mangrove. Most of the times, snails forage on the mud surface, during low tide, and climb back on trees well before the incoming tide. As soon as the sea retreats, the downward migration takes place and the snails spread again on the ground. The migratory behaviour of snails can vary widely, depending on the relative tide intensity, and different strategies can be exhibited. Individuals can spend several days on trees without migrating to the ground, around Spring Tides, or else, they might remain on the ground without bothering to migrate upwards, during Neap Tides, when the study area is not reached by the water. These irregular animal behaviours, relating to the complicated tide succession, can hardly be explained by the sole presence of an internal clock, and direct cues seem necessary to switch between different strategies, tuning the snails migratory behaviour to the actual local sea conditions.     

Automatic identification of mesocyclones and significant wind structures in Doppler radar images

The main objective of this work is to present the first version of the automatic mesocyclone detection algorithm for the Spanish weather Doppler radar, which has been developed during the last year at the Spanish Meteorological Service (INM). Taking into account that mesocyclones and other significant wind structures can be readily detected by single Doppler radar, the algorithm is based on the NSSL-MDA (The National Severe Storms Laboratory Mesoscale Detection Algorithm) approximation. It is specifically designed to automatically detect and identify radial velocity patterns associated with small-scale vortices and others wind structures. The different steps in the algorithm will be discussed and the application to a real situation will be presented. During 2004, the algorithm has been tested in an experimental phase, trying to adjust the needed parameters and thresholds. The plan for the future is to implement it within the operational procedure to automatically identify, analyse, diagnose, track and extrapolate convective structures and cells in radar data, improving the ability of the forecasters to provide timely warning of hazardous convective events.     

Headwaters drive streamflow and lowland tracer export in a large-scale humid tropical catchment

Headwaters are generally assumed to contribute the majority of water to downstream users, but how much water, of what quality and where it is generated are rarely known in the humid tropics. Here, using monthly monitoring in the data scarce (2,370 km²) San Carlos catchment in northeastern Costa Rica, we determined runoff-area relationships linked to geochemical and isotope tracers. We established 46 monitoring sites covering the full range of climatic, land use and geological gradients in the catchment. Regression and cluster analysis revealed unique spatial patterns and hydrologically functional landscape units. These units were used for seasonal and annual Bayesian tracer mixing models to assess spatial water source contributions to the outlet. Generally, the Bayesian mixing analysis showed that the chemical and isotopic imprint at the outlet is throughout the year dominated by the adjacent lowland catchments (68%) with much less tracer influence from the headwaters. However, the headwater catchments contributed the bulk of water and tracers to the outlet during the dry season (>50%) despite covering less than half of the total catchment area. Additionally, flow volumes seemed to be linearly scaled by area maintaining a link between the headwaters and the outlet particularly during high flows of the rainy season. Stable isotopes indicated mean recharge elevations above the mean catchment altitude, which further supports that headwaters were the primary source of downstream water. Our spatially detailed “snap-shot” sampling enabled a viable alternative source of large-scale hydrological process knowledge in the humid tropics with limited data availability.     

Summer phytoplankton composition and nitrogen limitation of the deep, naturally-acidic (pH2.2) Lake Caviahue, Patagonia, Argentina

During the warm seasons of 1998–2004, the naturally-acidic (pH2.2) Lake Caviahue was sampled for conductivity, temperature, oxygen, light, nutrients, and phytoplankton (density, biomass and chlorophyll a) with a view to studying the summer phytoplankton population changes with relation to environmental factors, as well as the significance of nitrogen limitation on the phytoplankton yield. Lake Caviahue is characterized by its low transparency, CO₂, and N concentration; significant P values; a distinctive vertical distribution of phytoplankton biomass with high values along the water column; and sometimes maximum meta-hypolimnion values. Biodiversity is very low as a result of extreme environmental conditions, Chlorophyceae being the prevailing algae group. Two types of bioassays were carried out to assess nitrogen limitation. For the first bioassay, a solution of ammonium–nitrogen chloride and/or wastewater (rich in ammonium and phosphorus) was used, while one of the lake's sediments was the source of nutrients for the second bioassay. Contrary to the case of acidic mining lakes, N-ammonium proved to be a significant supportive capacity limiting factor as to phytoplankton yield. The present paper provides for the first time information on phytoplankton nitrogen limitation in a naturally-acidic lake.     

Lunar meteorite regolith breccias: An in situ study of impact melt composition using LA‐ICP‐MS with implications for the composition of the lunar crust

Dar al Gani (DaG) 400, Meteorite Hills (MET) 01210, Pecora Escarpment (PCA) 02007, and MacAlpine Hills (MAC) 88104/88105 are lunar regolith breccia meteorites that provide sampling of the lunar surface from regions of the Moon that were not visited by the US Apollo or Soviet Luna sample return missions. They contain a heterogeneous clast population from a range of typical lunar lithologies. DaG 400, PCA 02007, and MAC 88104/88105 are primarily feldspathic in nature, and MET 01210 is composed of mare basalt material mixed with a lesser amount of feldspathic material. Here we present a compositional study of the impact melt and impact melt breccia clast population (i.e., clasts that were generated in impact cratering melting processes) within these meteorites using in situ electron microprobe and LA‐ICP‐MS techniques. Results show that all of the meteorites are dominated by impact lithologies that are relatively ferroan (Mg#_<70), have high Sc/Sm ratios (typically >10), and have low incompatible trace element (ITE) concentrations (i.e., typically <3.2 ppm Sm, <1.5 ppm Th). Feldspathic impact melt in DaG 400, PCA 02007, and MAC 88104/05 are similar in composition to that estimated composition for upper feldspathic lunar crust ( Korotev et al. 2003 ). However, these melt types are more mafic (i.e., less Eu, less Sr, more Sc) than feldspathic impact melts returned by the Apollo 16 mission (e.g., the group 3 and 4 varieties). Mafic impact melt clasts are common in MET 01210 and less common in PCA 02007 and MAC 88104/05. We show that unlike the Apollo mafic impact melt groups ( Jolliff 1998 ), these meteorite impact melts were not formed from melting large amounts of KREEP‐rich (typically >10 ppm Sm), High Magnesium Suite (typically >70 Mg#) or High Alkali Suite (high ITEs, Sc/Sm ratios <2) target rocks. Instead the meteorite mafic melts are more ferroan, KREEP‐poor and Sc‐rich, and represent mixing between feldspathic lithologies and low‐Ti or very low‐Ti (VLT) basalts. As PCA 02007 and MAC 88104/05 were likely sourced from the Outer‐Feldspathic Highlands Terrane our findings suggest that these predominantly feldspathic regions commonly contain a VLT to low‐Ti basalt contribution.     

An atmosphere–ocean regional climate model for the Mediterranean area: assessment of a present climate simulation

We present an atmosphere–ocean regional climate model for the Mediterranean basin, called the PROTHEUS system, composed by the regional climate model RegCM3 as the atmospheric component and by a regional configuration of the MITgcm model as the oceanic component. The model is applied to an area encompassing the Mediterranean Sea and compared to a stand-alone version of its atmospheric component. An assessment of the model performances is done by using available observational datasets. Despite a persistent bias, the PROTHEUS system is able to capture the inter-annual variability of seasonal sea surface temperature (SST) and also the fine scale spatio-temporal evolution of observed SST anomalies, with spatial correlation as high as 0.7 during summer. The close inspection of a 10-day strong wind event during the summer of 2000 proves the capability of the PROTHEUS system to correctly describe the daily evolution of SST under strong air–sea interaction conditions. As a consequence of the model’s skill in reproducing observed SST and wind fields, we expect a reliable estimation of air–sea fluxes. The model skill in reproducing climatological land surface fields is in line with that of state of the art regional climate models.     

Locating diversity: race,nativity and place in health disparities research

Nancy Krieger has been one of the leading voices in documenting how social ‘axes of difference’, including race, ethnicity and class make people vulnerable to poor health and limit their access to effective health care. We discuss the importance of ‘locating’ diversity in health inequalities research. This includes critically dissecting racial and ethnic axes into more nuanced social categories that incorporate differences based on immigration and other factors. It also involves considering how diverse population groups vary in their perception and use of space for health-related activities and exposures. Examples relating to immigrant populations’ health and access to health care are discussed.