Changes in the sub-Antarctic in the modern era of science and environmental consciousness

This paper defines the "modern era of science and environmental consciousness" both in a global sense and, more specifically, when applied to the sub-Antarctic archipelagos.It briefly describes some key changes occurring in the sub-Antarctic terrestrial biome including climate change and the introduction of non-indigenous species

The impact of landscape sparsification on modelling and analysis of the invasion process

Climate change is a major threat to species, unless their populations are able to invade and colonise new landscapes of more suitable environment. In this paper, we propose a new model of the invasion process using a tool of landscape network sparsification to efficiently estimate a duration of the process. More specifically, we aim to simplify the structure of large landscapes using the concept of sparsification in order to substantially decrease the time required to compute a good estimate of the invasion time in these landscapes. For this purpose, two different simulation methods have been compared: full and R-local simulations, which are based on the concept of dense and sparse networks, respectively. These two methods are applied to real heterogeneous landscapes in the United Kingdom to compute the total estimated time to invade landscapes. We examine how the duration of the invasion process is affected by different factors, such as dispersal coefficient, landscape quality and landscape size. Extensive evaluations have been carried out, showing that the R-local method approximates the duration of the invasion process to high accuracy using a substantially reduced computation time

A paleolimnological reconstruction of mid and late holocene climate change in South Georgia

South Georgia is located at the barrier between Antarctica and the mid-latitudes which makes it a key location to determine the main drivers of past and present-day climate variability and to assess whether the climate in the South Atlantic was synchronous with Antarctica or South America. Here we performed a sedimentological, high resolution (ITRAX) geochemical, and fossil diatom and pigment analysis of a 5.41 m long, ca. 8000 cal yr BP, sediment core from Fan Lake, Annenkov Island, South Georgia (54°29’0’’S, 37°5’0’’W) in an attempt to separate the influence of Holocene palaeoclimatic variability from changes in catchment stability and glacier activity. While radiocarbon ages of events in the top 250 cm (c. 4 ka) of this core appear to be broadly in line with some other studies on South Georgia, the chronology of the lower half still poses several questions. The main lithological division in the profile is marked by the establishment of finely laminated sedimentation at c. 250 cm (4000 yrs BP) and is also picked out by the diatom and pigment analysis. This change is characterized by a reduction to low stable magnetic susceptibility values and a step-change increase in organic matter, and is most likely related to deglaciation of the lake catchment during the ‘Mid Holocene Hypsithermal’. Although the diatom composition is dominated by a single species (i.e., Cyclotella stelligera), relatively minor, but sometimes significant, fluctuations in other diatom species occur in the top 250 cm (mid-late Holocene). Interestingly, the most remarkable change in the diatom record occurs at c. 100 cm (1000 cal yr BP) and coincides with an increase in general lake productivity. We link these changes to increased catchment disturbance at c. 1000 cal yr BP, which is possibly associated with deglaciation following one of four relatively minor ‘post-cooling events’ during the late Holocene

Assessment of the Effectiveness of the Portuguese Implementation. VRU-TOO Deliverable 12.

The work of VRU-TOO is targeted specifically at the application of AlT for the reduction of risk and the improvement of comfort for vulnerable road users, namely pedestrians. To achieve this, the project has combined pilot implementations in three countries (UK, Greece and portugal) with behavioural studies and the development of computer simulation techniques. At the same time the pilot implementations have been co-ordinated with local and national policy priorities. This deliverable presents the results from a trial that was carried out on a major arterial road just outside the central area of Porto, Portugal The objective of the trial was to show that it was possible to improve the safety and mobility of pedestrians at a junction and crossing facility which was situated adjacent to a large school by intelligent manipulation of the signal settings. Pedestrian detectors were attached to the traffic signals in order to detect pedestrians as they approached the crossing point. As a result of this detection, in certain circumstances, the signal cycle would be advanced so as to reduce the time until the signals would change to present the pedestrian with an opportunity to cross the road. The detectors would also allow the green time for pedestrians to be extended if there was sufficient demand, allowing safer and more comfortable crossing periods. Finally the pedestrian green time could also be reduced in order to avoid wasted time, if there was no pedestrian demand, thus allowing a more optimised functioning of the junction. In order to evaluate the effectiveness of this treatment an extensive "before and after" analysis was carried out to determine the changes in safety and mobility, especially for child pedestrians. The evaluation of the trial was carried out by using the data collected to assess whether the pre- specified objectives have been achieved. The implications of the results are then discussed as well as their implication to the more general installation of such measures in the Portuguese contex

The missing piece of the South Atlantic jigsaw: when continental break-up ignores crustal heterogeneity

Crustal heterogeneity is considered to play a critical role in the position of continental break-up, yet this can only be demonstrated when a fully constrained pre-break-up configuration of both conjugate margins is achievable. Limitations in our understanding of the pre-break-up crustal structure in the offshore region of many margins preclude this. In the southern South Atlantic, which is an archetypal conjugate margin, this can be achieved because of the high confidence in plate reconstruction. Prior to addressing the role of crustal heterogeneity, two questions have to be addressed: first, what is the location of the regionally extensive Gondwanan Orogeny that remains enigmatic in the Orange Basin, offshore South Africa; and, second, although it has been established that the Argentinian Colorado rift basin has an east–west trend perpendicular to the Orange Basin and Atlantic spreading, where is the western continuation of this east–west trend? We present here a revised structural model for the southern South Atlantic by identifying the South African fold belt offshore. The fold belt trend changes from north–south to east–west offshore and correlates directly with the restored Colorado Basin. The Colorado–Orange rifts form a tripartite system with the Namibian Gariep Belt, which we call the Garies Triple Junction. All three rift branches were active during the break-up of Gondwana, but during the Atlantic rift phase the Colorado Basin failed while the other two branches continued to rift, defining the present day location of the South Atlantic. In addressing these two outstanding questions, this study challenges the premise that crustal heterogeneity controls the position of continental break-up because seafloor spreading demonstrably cross-cuts the pre-existing crustal heterogeneity. Furthermore, we highlight the importance of differentiating between early rift evolution and subsequent rifting that occurs immediately prior to seafloor spreading

Salt-Enrichment Impact on Biomass Production in a Natural Population of Peatland Dwelling Arcellinida and Euglyphida (Testate Amoebae)

This is the final version. Available on open access from Springer Verlag via the DOI in this recordUnicellular free-living microbial eukaryotes of the order Arcellinida (Tubulinea; Amoebozoa) and Euglyphida (Cercozoa; SAR), commonly termed testate amoebae, colonise almost every freshwater ecosystem on Earth. Patterns in the distribution and productivity of these organisms are strongly linked to abiotic conditions—particularly moisture availability and temperature—however, the ecological impacts of changes in salinity remain poorly documented. Here, we examine how variable salt concentrations affect a natural community of Arcellinida and Euglyphida on a freshwater sub-Antarctic peatland. We principally report that deposition of wind-blown oceanic salt-spray aerosols onto the peatland surface corresponds to a strong reduction in biomass and to an alteration in the taxonomic composition of communities in favour of generalist taxa. Our results suggest novel applications of this response as a sensitive tool to monitor salinisation of coastal soils and to detect salinity changes within peatland palaeoclimate archives. Specifically, we suggest that these relationships could be used to reconstruct millennial scale variability in salt-spray deposition—a proxy for changes in wind-conditions—from sub-fossil communities of Arcellinida and Euglyphida preserved in exposed coastal peatlands.Natural Environment Research Council (NERC

Insider sales vs. short selling: negative information trading in Australia

We show that Australian short sellers do not front-run insider sales. Results are robust to conditional trading classified by book-to-market, intangible ratios, industry and multiple factor analysis. The combination of insider sales and short selling provides a contrarian signal that dampens prior overpricing, but is not associated with subsequent abnormal returns. We contend that the business environment in Australia, together with the daily reporting of short sales, plays a significant role in restraining short selling profitability. Our results contradict front-running by short sellers in the U.S., where the reporting and litigation environment induces the leakage of pre-traded negative information by corporate insiders. Overall, we highlight how information flow direction and profitability can be affected by different country legal and business cultures