The Seventh Kew Environmental Lecture: Our global future: climate change

The Kew lecture provides a major contribution to contemporary environmental views. The Hon. Timothy E. Wirth is US Under Secretary of State for Global Affairs and he is responsible within the US State Department for overseeing environment, population, human rights, refugee, narcotics and related programmes. He was elected to the US Senate from Colorado in 1986 and served until 1993 when he chose not to run for re-election. He was, previously, a Congressman for 12 years and was voted one of the 25 most effective Members of Congress. In 1992, he served as national co-chair of the Clinton – Gore presidential campaign. The lecture was delivered at the Royal Botanic Gardens, Kew, London, on 15 September 1997.     

Hastigerina pelagica: Foraminiferal habitat for planktonic dinoflagellates

Hand-collection of specimens by SCUBA diving in the Florida Current revealed that the planktonic foraminiferan Hastigerina pelagica harbors on its surfaces 3 species of planktonic dinoflagellates: Pyrocystis fusiformis, P. noctiluca and, predominanty, Dissodinium elegans. Undamaged H. pelagica is unique in possessing a gelatinous, bubble-like capsule completely surrounding the test. While attached to the surface of this capsule, the dinoflagellates frequently reproduced asexually, and appeared healthy in all respects. They were not assimilated by the foraminifera. The number of D. elegans per foraminiferan increased with increased surface area of the gelatinous capsule, averaging approximately 6 dinoflagellates/foraminiferan, with a maximum of 79. Surface-space utilization per D. elegans remained constant with increased foraminiferan size. The use of the foraminifera in a facultative commensal or symbiotic association and the value of surfaces in that association is postulated.     

Sexual chases in sand martins (Riparia riparia): cues for males to increase their reproductive success

Summary During the pre-laying and laying stages of the breeding cycle, female sand martins are guarded by their mates and chased by other males seeking promiscuous copulations. Because females become exceptionally heavy when they are most likely to be fertile, their increased mass was thought to present cues during flight to males seeking promiscuous copulations. Heavy female sand martins released from the hand were selectively chased in sexual chases (Figs. 1, 2). Breeding females were heaviest during laying and pre-laying (Fig. 3), exceeding any masses normally achieved by breeding males (Fig. 3). A sample of naturally heavy females and birds whose mass had been experimentally increased to that of laying and prelaying females took longer to reach ascending flight, as determined by analysis of video recordings, than a sample of lighter birds (Table 1). It was concluded that this and other flight cues may be detected by males so that they may achieve extra-pair copulations and hence increase their reproductive success.     

The measurement of intracellular zinc in human intestinal mucosa using x-ray microanalysis

The zinc content of intestinal epithelial cells in human jejunum and ileum has been measured using X-ray microanalysis. The range of values was wide, the highest being found in stem cells and enterocytes. Significant differences were found in jejunum from gastric carcinoma patients and ileum from Crohn's disease patients compared with patients with non malignant, non inflammatory disease.     

The mental health of expatriate and Kosovar Albanian humanitarian aid workers

The mental health consequences of exposure to traumatic events and the risk factors for psychological morbidity among expatriate and Kosovar Albanian humanitarian aid workers have not been well studied. In June 2000, we used standardised screening tools to survey 285 (69.5%) of 410 expatriate aid workers and 325 (75.8%) of 429 Kosovar Albanian aid workers from 22 humanitarian organizations that were implementing health programmes in Kosovo. The mean number of trauma events experienced by expatriates was 2.8 (standard deviation: 2.7) and by Kosovar staff 3.2 (standard deviation: 2.8). Although only 1.1% of expatriate and 6.2% of Kosovar aid workers reported symptoms consistent with the diagnosis for post-traumatic stress disorder, 17.2% and 16.9%, respectively, reported symptoms satisfying the definition of depression. Regression analysis demonstrated that the number of trauma events experienced was significantly associated with depression for the two sets of workers. Organisational support services may be an important mediating factor and should be targeted at both groups.     

The implosion of the Calgary General Hospital: ambient air quality issues

This paper discusses the implosion of a large inner-city hospital in Calgary, Alberta, Canada, on October 4, 1998. Stationary and mobile air monitoring conducted after the implosion indicated there were several short-term air quality issues, including significant temporal increases in total suspended particles, particulate matter (PM) with aerodynamic diameter less than or equal to 10 microm (PM10), PM with aerodynamic diameter less than or equal to 2.5 microm (PM2.5), asbestos, and airborne and settled lead. In addition, the implosion created a dust cloud that traveled much further than expected, out to 20 km. The ability of an implosion to effectively aerosolize building materials requires the removal of all friable and nonfriable forms of asbestos and all Pb-containing painted surfaces during pre-implosion preparatory work. Public advisories to mitigate personal exposure and indoor migration of the implosion dust cloud constituents should extend to 10 or 20 km around an implosion site. These findings point to a number of complex and problematic issues regarding implosions and safeguarding human health and suggest that implosions in metropolitan areas should be prohibited. Further work to characterize the public health risks of conventional versus implosion demolition is recommended.     

Reconstruction of historical trends of PCDD/Fs and PCBs in the Venice Lagoon, Italy

Historical trends of PCDD/Fs and PCBs from the year 1900 have been reconstructed for the Venice Lagoon area by using a fugacity-based dynamic multimedia model. A novel approach to estimate the inputs to the system was applied. Emissions to the lagoon were estimated by studying dated sediment cores taken from salt marshes located in the lagoon area. These cores have recently proven to be a suitable tool to reconstruct the temporal trends of atmospheric deposition of POPs. According to the model, concentrations of PCBs and PCDD/Fs in air and water reflect the trends of their production and usage, peaking during the 1960s. The peaks in the sediment were delayed by 5-40 years depending on the congener. Predicted concentrations are in good agreement with experimental results. The most important input parameters, identified by a sensitivity analysis, are the degradation constants, K(ow), the Henry's law constant, vapour pressure, active sediment depth, sediment resuspension, and deposition rates, and water residence time in the lagoon.     

Detection of scale-specific community dynamics using wavelets

The response of ecological communities to anthropogenic disturbance is of both scientific and practical interest. Communities where all species respond to disturbance in a similar fashion (synchrony) will exhibit large fluctuations in total biomass and dramatic changes in ecosystem function. Communities where some species increase in abundance while others decrease after disturbance (compensation) can maintain total biomass and ecosystem function in the face of anthropogenic change. We examined dynamics of the Little Rock Lake (Wisconsin, USA) zooplankton community in the context of an experimental pH manipulation conducted in one basin of the lake. A novel application of wavelets was used to partition patterns of synchrony and compensation by time scale. We find interestingly that some time series show both patterns of synchrony and compensation depending on the scale of analysis. Within the unmanipulated basin, we found subtle patterns of synchrony and compensation within the community, largely at a one-year time scale corresponding to seasonal variation. Within the acidified lake basin, dynamics shifted to longer time scales corresponding to the pattern of pH manipulation. Comparisons between pairs of species in different functional groups showed both strong compensatory and synchronous responses to disturbance. The strongest compensatory signal was observed for two species of Daphnia whose life history traits lead to synchrony at annual time scales, but whose differential sensitivity to acidification led to compensation at multiannual time scales. The separation of time scales inherent in the wavelet method greatly facilitated interpretation as patterns resulting from seasonal drivers could be separated from patterns driven by pH manipulation.