High CO₂ and marine animal behaviour: potential mechanisms and ecological consequences

Exposure to pollution and environmental change can alter the behaviour of aquatic animals and here we review recent evidence that exposure to elevated CO? and reduced sea water pH alters the behaviour of tropical reef fish and hermit crabs. Three main routes through which behaviour might be altered are discussed; elevated metabolic load, 'info-disruption' and avoidance behaviour away from polluted locations. There is clear experimental evidence that exposure to high CO? disrupts the ability to find settlement sites and shelters, the ability to detect predators and the ability to detect prey and food. In marine vertebrates and marine crustaceans behavioural change appears to occur via info-disruption. In hermit crabs and other crustaceans impairment of performance capacities might also play a role. We discuss the implications for such behavioural changes in terms of potential impacts at the levels of population health and ecosystem services, and consider future directions for research.     

Arsenic sequestration by sorption processes in high-iron sediments

High-iron sediments in North Haiwee Reservoir (Olancha, CA), resulting from water treatment for removal of elevated dissolved arsenic in the Los Angeles Aqueduct system, were studied to examine arsenic partitioning between solid phases and porewaters undergoing shallow burial. To reduce arsenic in drinking water supplies, ferric chloride and a cationic polymer coagulant are added to the aqueduct upstream of Haiwee Reservoir, forming an iron-rich floc that scavenges arsenic from the water. Analysis by synchrotron X-ray absorption spectroscopy (XAS) showed that the aqueduct precipitate is an amorphous hydrous ferric oxide (HFO) similar to ferrihydrite, and that arsenic is associated with the floc as adsorbed and/or coprecipitated As(V). Arsenic-rich floc and sediments are deposited along the inlet channel as aqueduct waters enter the reservoir. Sediment core samples were collected in two consecutive years from the edge of the reservoir along the inlet channel using 30- or 90-cm push cores. Cores were analyzed for total and extractable arsenic and iron concentrations. Arsenic and iron speciation and mineralogy in sediments were examined at selected depths by synchrotron XAS and X-ray diffraction (XRD). Sediment-porewater measurements were made adjacent to the core sample sites using polyacrylamide gel probe samplers. Results showed that sediment As(V) is reduced to As(III) in all cores at or near the sediment-water interface (0-4 cm), and only As(III) was observed in deeper sediments. Analyses of EXAFS spectra indicated that arsenic is present in the sediments mostly as a bidentate-binuclear, inner-sphere sorption complex with local atomic geometries similar to those found in laboratory studies. Below about 10 cm depth, XAS indicated that the HFO floc had been reduced to a mixed Fe(II, III) solid with a local structure similar to that of synthetic green rust (GR) but with a slightly contracted average interatomic Fe-Fe distance in the hydroxide layer. There was no evidence from XRD for the formation of a crystalline GR phase. The release of dissolved iron (presumably Fe²⁺) and arsenic to solution, as monitored by in situ gel probes, was variable but, in general, occurred at greater depths than arsenic reduction in the sediments by spectroscopic observations and appears to be near or below the depth at which sediment GR was identified. These data point to reductive dissolution of the sorbent iron phase as the primary mechanism of release of sorbed arsenic to solution.     

Defining an absolute reference frame for ‘clumped’ isotope studies of CO2

We present a revised approach for standardizing and reporting analyses of multiply substituted isotopologues of CO₂ (i.e., ‘clumped’ isotopic species, especially the mass-47 isotopologues). Our approach standardizes such data to an absolute reference frame based on theoretical predictions of the abundances of multiply-substituted isotopologues in gaseous CO₂ at thermodynamic equilibrium. This reference frame is preferred over an inter-laboratory calibration of carbonates because it enables all laboratories measuring mass 47 CO₂ to use a common scale that is tied directly to theoretical predictions of clumping in CO₂, regardless of the laboratory’s primary research field (carbonate thermometry or CO₂ biogeochemistry); it explicitly accounts for mass spectrometric artifacts rather than convolving (and potentially confusing) them with chemical fractionations associated with sample preparation; and it is based on a thermodynamic equilibrium that can be experimentally established in any suitably equipped laboratory using commonly available materials.By analyzing CO₂ gases that have been subjected to established laboratory procedures known to promote isotopic equilibrium (i.e., heated gases and water-equilibrated CO₂), and by reference to thermodynamic predictions of equilibrium isotopic distributions, it is possible to construct an empirical transfer function that is applicable to data with unknown clumped isotope signatures. This transfer function empirically accounts for the fragmentation and recombination reactions that occur in electron impact ionization sources and other mass spectrometric artifacts. We describe the protocol necessary to construct such a reference frame, the method for converting gases with unknown clumped isotope compositions to this reference frame, and suggest a protocol for ensuring that all reported isotopic compositions (e.g., Δ₄₇ values; [Eiler and Schauble, 2004] and [Eiler, 2007]) can be compared among different laboratories and instruments, independent of laboratory-specific analytical or methodological differences. We then discuss the use of intra-laboratory secondary reference frames (e.g., based on carbonate standards) that can be more easily used to track the evolution of each laboratory’s empirical transfer function. Finally, we show inter-laboratory reproducibility on the order of ±0.010 (1σ) for four carbonate standards, and present revised paleotemperature scales that should be used to convert carbonate clumped isotope signatures to temperature when using the absolute reference frame described here. Even when using the reference frame, small discrepancies remain between two previously published synthetic carbonate calibrations. We discuss possible reasons for these discrepancies, and highlight the need for additional low temperature (<15 °C) synthetic carbonate experiments.     

A 16,000 C yr B.P. packrat midden series from the USA–Mexico Borderlands

A new packrat midden chronology from Playas Valley, southwestern New Mexico, is the first installment of an ongoing effort to reconstruct paleovegetation and paleoclimate in the U.S.A.–Mexico Borderlands. Playas Valley and neighboring basins supported pluvial lakes during full and/or late glacial times. Plant macrofossil and pollen assemblages from nine middens in the Playas Valley allow comparisons of two time intervals: 16,000–10,000 and 4000–0 ¹⁴C yr B.P. Vegetation along pluvial lake margins consisted of open pinyon–juniper communities dominated by Pinus edulis, Juniperus scopulorum, Juniperus cf. coahuilensis, and a rich understory of C₄ annuals and grasses. This summer-flowering understory is also characteristic of modern desert grassland in the Borderlands and indicates at least moderate summer precipitation. P. edulis and J. scopulorum disappeared or were rare in the midden record by 10,670 ¹⁴C yr B.P. The late Holocene is marked by the arrival of Chihuahuan desert scrub elements and few departures as the vegetation gradually became modern in character. Larrea tridentata appears as late as 2190 ¹⁴C yr B.P. based on macrofossils, but may have been present as early as 4095 ¹⁴C yr B.P. based on pollen. Fouquieria splendens, one of the dominant desert species present at the site today, makes its first appearance only in the last millennium. The midden pollen assemblages are difficult to interpret; they lack modern analogs in surface pollen assemblages from stock tanks at different elevations in the Borderlands.     

Health profiles of Hamilton: Spatial characterisation of neighbourhoods for health investigations

This paper is part of a larger research program which employs a mixed-methods approach to study the determinants of health at the local level using specific neighborhoods in Hamilton, Ontario, Canada. In this paper, multivariate, spatial statistical techniques and geographic information systems are used to address questions about the characterization of neighbourhoods, based on socioeconomic determinants of health and risk factors such as smoking. While neighbourhood characterization has been a component of public health surveillance for some time, geostatistical techniques can now be used to derive more accurate representation of neighbourhoods for use in subsequent analysis. We utilize principal components analysis to reduce the data and extract the components that represent the underlying local processes. Principal components are also overlayed on comparative mortality figures to visualize where the socio-demographic determinants of health correspond spatially with mortality patterns. Predicted values from the components are then analysed for spatial clustering using local indicators of spatial association. The findings reveal a pattern of distinct neighbourhoods that will be used in subsequent quantitative and qualitative stages in the larger research programme. The results can also be used to inform public health policy and to target public health interventions.     

Natural hazard impacts in small island developing states: A review of current knowledge and future research needs

Small island developing states (or SIDS) are exposed to a large number of natural hazards and many characteristics of small island developing states make them particularly vulnerable to the impacts of natural hazards. In spite of this acknowledged vulnerability, there are relatively few studies which focus on the impacts of natural hazards in these countries. This paper presents a review of our current state of knowledge of impacts in small island developing states and highlights a number of research needs. Central to these is the need to integrate natural hazards research within a sustainable development context and the need to exploit existing procedures such as government coordinated disaster impact assessments to generate a detailed understanding of natural hazards impacts.     

Moving young lives: Mobility, immobility and inter-generational tensions in urban Africa

This paper explores young people’s experiences and perceptions of mobility and mobility constraints in poorer urban areas of Ghana, Malawi and South Africa within the specific context of inter-generational relations. Drawing principally on qualitative research findings from a study involving both adult and child researchers, our aim is to chart the diversities and commonalities of urban young people’s mobility experiences in the everyday - how they use and experience the city - developing a comparative perspective across three urban study sites which links young people’s mobility with the power relations that operate to shape their movements in individual locations. In particular, we consider how positive and negative images of young people’s mobility play out in terms of the inter-generational frictions and negotiations generated by their mobility performances. We also reflect on the developmental implications, in terms of young people’s access to services and income and their participation in the social networks and peer culture which may shape their life trajectories. Three themes are explored in detail: mobility as challenge, mobility as temptation and mobility control.     

Africa in the rise of rights-based development

This paper explores the rise of rights-based development (RBD) and its endorsement by prominent international institutions (such as the United Nations) and International Development Agencies (IDAs) like the World Bank. It situates RBD in global political context and analyses it in relation to the international politics of development, especially the politics of neo-liberal adjustment policies in Africa. The paper shows how RBD emerged against a backdrop of debate about four international issues associated with neo-liberalism and its discontents, namely globalisation and uneven development; capability and good governance; human rights and human development; and NGOs in the politics of development. Debates about those four issues keep repositioning the state as the central actor in RBD, and holding the state accountable for development (or the lack thereof) under international law. The paper’s basic point is that state-centric RBD is paradoxical and highly political. Greater accountability is being demanded of states––especially in Africa––from the same neo-liberal forces (such as the World Bank) charged with weakening state capacity, undermining democracy, and diminishing state authority. In terms of international power relations and the politics of development, RBD does signal something of a willingness to rethink certain aspects of the dominant neo-liberal agenda. And yet adjusted states are being subjected––in the name of RBD––to novel methods of international surveillance and forms of conditionality. States are ultimately held responsible for human rights violations, even when it is non-state actors (and their neo-liberal policies) that caused those rights to be violated in the first place. RBD is, therefore, a partial answer (at best) to the questions of empowerment and change raised by critics of neo-liberalism.     

Ecologically Sustainable Fishing in Theory and Practice: Individual transferable quotas in Australia's South East Fishery

In 1988, responding to international legislation that requires sustainable fishery management, the Australian Fishery Management Authority (AFMA) implemented an individual transferable quota (ITQ) management system to address the environmental crisis in the South East Fishery. Defining sustainability in its broadest context to include social as well as economic and ecological dimensions, this paper firstly describes the environmental crisis and the South East Fishery's ITQ management system. Secondly, Christy's (1973) paper is employed as a catalyst to compare the theoretical socio-economic outcomes with the actual operation of ITQs. The brief South East Fishery experience suggests that the logic behind ITQs is correct. Production has become reorganised. Operators are not only fewer, but also embrace professionalism, quality, efficiency, and the operation of the free market within the industry. However, because of the local idiosyncrasies of this multi-species fishery, the legislation over territorial waters, and the absence of alternative employment, fishers have adopted non-quota fishing techniques and entered seas under New South Wales jurisdiction. Without a social re-adjustment policy or buy-out scheme, the AFMA's objective of ecologically sustainable development cannot be attained.