Climate and land-use change impact on faecal indicator bacteria in a temperate maritime catchment (the River Conwy, Wales)

Water-borne pathogen contamination from untreated sewage effluent and runoff from farms is a serious threat to the use of river water for drinking and commercial purposes, such as downstream estuarine shellfish industries. In this study, the impact of climate change and land-use change on the presence of faecal indicator bacteria in freshwater was evaluated, through the use of a recently-developed catchment-scale pathogen model. The River Conwy in Wales has been used as a case-study, because of the large presence of livestock in the catchment and the importance of the shellfish harvesting activities in its estuary. The INCA-Pathogens catchment model has been calibrated through the use of a Monte-Carlo-based technique, based on faecal indicator bacteria measurements, and then driven by an ensemble of climate projections obtained from the HadRM3-PPE model (Future Flow Climate) plus four land-use scenarios (current land use, managed ecosystem, abandonment and agricultural intensification). The results show that climate change is not expected to have a very large impact on average river flow, although it might alter its seasonality. The abundance of faecal indicator bacteria is expected to decrease in response to climate change, especially during the summer months, due to reduced precipitation, causing reduced runoff, and increased temperature, which enhances the bacterial die-off processes. Land-use change can also have a potentially large impact on pathogens. The “managed ecosystems” scenario proposed in this study can cause a reduction of 15% in average water faecal indicator bacteria and up to 30% in the 90th percentile of water faecal indicator bacteria, mainly due to the conversion of pasture land into grassland and the expansion of forest land. This study provides an example of how to assess the impacts of human interventions on the landscape, and what may be the extent of their effects, for other catchments where the human use of the natural resources in the uplands can jeopardise the use of natural resources downstream

The X-ray properties of the young open cluster around #alpha# Persei

We present ROSAT PSPC pointed observations of the 50 Myr old #alpha# Per open cluster. The X-ray observations, which were carried out as a raster scan, cover an area of about 10 deg"2. In total, we detect about 160 X-ray sources, 88 of which have an optical counterpart (with 30 arcsec) associated with #alpha# Per cluster candidates. Within the central region of our field of view, which is characterized by a limiting sensitivity L_X #approx# 10"2"8"."8"-"2"9 erg sec"-"1, we detect basically all late-F, G and K stars, while the detection rate among the M dwarfs is on the order of 60%. Given the sensitivity of our X-ray observations, the lower detection rate among the very low mass objects is consistent with the ROSAT results obtained for the Pleiades cluster. Although stars in each color range show a large spread in X-ray luminosity, the maximal X-ray luminosities appear to decrease from the range of late-F-G type stars to the M-type dwarfs. A comparison of the X-ray luminosity distribution functions (XLDF) for our #alpha# Per sample and the Pleiades indicates that F and G-type stars in #alpha# Per are, as a whole, more X-ray luminous than their older counterparts in the Pleiades. On the other hand, no significant difference is found between the distributions of the K and M-type dwarfs in the two clusters. We argue that this finding is a consequence of the longer spin-down timescales of later-type objects, and hence of the fact that there are more rapid rotators among G stars in #alpha# Per than in the Pleiades, while this is not the case for K and M dwarfs. (orig.)SIGLEAvailable from TIB Hannover: RN 9303(329) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

A X-ray study of the young open cluster IC 2602

We present the results of ROSAT PSPC observations of the 30 Myr old IC 2602 cluster; for the X-ray detected objects the results of a CCD photometric survey are also given. In X-rays, we detect a total of 110 objects within a 11 deg"2 area, above a threshold of typically 3-5 x 10"2"8erg/sec. 68 of the detected objects have been identified with at least one optical counterpart; 44 of these are new optical candidates for cluster membership provided by our CCD photometry. Stars of all spectral types have been detected, from the very early-types to the late-M dwarfs. Soft X-ray luminosities range between about 10"2"9 erg/sec to a few 10"3"0 erg/sec, with the maximum and average L_X decreasing with spectral type for B-V larger than #approx# 0.8. Many of the stars redder than B-V #approx# 0.8 show a L_X/L_b_o_l ratio at about the saturation level of 10"-"3. We construct X-ray luminosity distribution functions for objects in different color ranges and we compare them with those for the Pleiades. F, G, and early-K type candidates in IC 2602 appear to be more X-ray luminous than in the Pleiades, while no significant difference is seen among late-K and M dwarfs. Under the assumption that our IC 2602 sample is not severely affected by incompleteness, we argue that the above finding is related to the distribution of rotational velocities in the two clusters, with most of the late-type stars being fast rotators in both clusters, while, due to different spin-down timescales, the earlier type stars in IC 2602 are likely to rotate more rapidly than their counterparts in the Pleiades. (orig.)Available from TIB Hannover: RN 9303(307) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Future novel threats and opportunities facing UK biodiversity identified by horizon scanning.

1. Horizon scanning is an essential tool for environmental scientists if they are to contribute to the evidence base for Government, its agencies and other decision makers to devise and implement environmental policies. The implication of not foreseeing issues that are foreseeable is illustrated by the contentious responses to genetically modified herbicide-tolerant crops in the UK, and by challenges surrounding biofuels, foot and mouth disease, avian influenza and climate change. 2. A total of 35 representatives from organizations involved in environmental policy, academia, scientific journalism and horizon scanning were asked to use wide consultation to identify the future novel or step changes in threats to, and opportunities for, biodiversity that might arise in the UK up to 2050, but that had not been important in the recent past. At least 452 people were consulted. 3. Cases for 195 submitted issues were distributed to all participants for comments and additions. All issues were scored (probability, hazard, novelty and overall score) prior to a 2-day workshop. Shortlisting to 41 issues and then the final 25 issues, together with refinement of these issues, took place at the workshop during another two rounds of discussion and scoring. 4. We provide summaries of the 25 shortlisted issues and outline the research needs. 5. We suggest that horizon scanning incorporating wide consultation with providers and users of environmental science is used by environmental policy makers and researchers. This can be used to identify gaps in knowledge and policy, and to identify future key issues for biodiversity, including those arising from outside the domains of ecology and biodiversity. 6. Synthesis and applications. Horizon scanning can be used by environmental policy makers and researchers to identify gaps in knowledge and policy. Drawing on the experience, expertise and research of policy advisors, academics and journalists, this exercise helps set the agenda for policy, practice and research