Using Remote Sensing to Reassess the Mass Mortality of Diadema antillarum 1983–1984

Abstract: The 1983–1984 mass mortality of the sea urchin Diadema antillarum remains one of the most severe die-offs ever recorded in the Caribbean. Before 1983, the herbivore D. antillarum was pervasive on coral reefs in the region. Nine months after first detection of the mass mortality, 95% of the urchins had perished, and algal cover of coral increased between 100% and 250%. A water-borne pathogen was hypothesized as the causative agent, but it was never isolated. To date, surface current patterns have been used exclusively to explain both the cause and the distribution patterns of the mortality event. Using archived satellite images, we re-examined the water-borne pathogen hypothesis and investigated whether other mechanisms could also account for the dissemination pattern in some areas. In addition, archived satellite images were utilized to detect changes in coral reef reflectance. For infections in the Gulf of Mexico and Bermuda, satellite images confirm that surface currents are likely responsible for the distribution of the pathogen. For infections in the eastern Caribbean (Curacao, U.S. Virgin Islands, Barbados), however, another mechanism, possibly ballast water exchange, must be considered because the surface current and infection patterns do not coincide. Changes in coral reflectance were detectable from Landsat thermatic mapping data before and after the mass mortality and correspond to the change in algal cover. Results from our study demonstrate the potential of satellite images for use in determining connectivity between regions of the Caribbean and in detecting changes in coral reef cover.     

Corona ion induced atmospheric potential gradient perturbations near high voltage power lines

High voltage power lines are known to produce corona ions that can be carried from the line by the wind, progressively attaching to ambient aerosol particles and causing fluctuations in the Earth’s atmospheric potential gradient. A fixed site monitoring station was installed near two power lines, which recorded the potential gradient at 1 s intervals and the ambient weather conditions every 10 min. The station ran continuously from January 2007 to December 2008, accumulating long-term data. Results from 2008 show an increase in potential gradient variability when a wind is blowing across the power lines towards the station, indicating that corona ions may be present in this environment.     

Omphalocele—What should we tell the prospective parents?

An omphalocele is a congenital defect in the abdominal wall characterized by absent abdominal muscles, fascia, and skin. The characteristic ultrasound appearance includes a midline defect with herniation of abdominal contents into the base of the umbilical cord. Other anatomic abnormalities are seen in approximately 50% of cases, most notably cardiac defects (19%–32%). Approximately, 50% of cases are associated with genetic and multiple malformation syndromes including trisomy 13/18, pentalogy of Cantrell and Beckwith–Wiedemann syndrome. Therefore, a thorough evaluation is recommended, including detailed anatomic survey, fetal echocardiogram, genetic counseling, and prenatal diagnostic testing. Overall prognosis depends on the size of the omphalocele, genetic studies, and associated anomalies. Early prenatal diagnosis remains important in order to provide parental counseling and assist in pregnancy management. Delivery should occur at a tertiary care center. Timing and mode of delivery should be based on standard obstetric indications with cesarean delivery reserved for large omphalocele (>5 cm) or those that involve the fetal liver. Neonatal management involves either primary or staged reduction, both of which can be associated with a prolonged neonatal hospitalization.     

Water metering policies in the former Soviet Union: lessons from Lviv,Ukraine

A study of the feasibility of installing domestic water meters in Lviv, Ukraine, was undertaken. A driving force behind the study was the key role that metering plays in determining optimal water demand management strategies. Because many laws, regulations, operations, and construction practices were standardized throughout the Soviet Union, domestic water metering strategies determined to be operable in Lviv may have some application to other former Soviet Union cities. Results indicate that, although water metering of individual apartment units in Lviv is not financially feasible when paid for by the water utility, water metering at the building level, when combined with other elements of demand management and cost recovery strategies, may enable local water infrastructure authorities to devise ways of putting their utilities on a financially sustainable basis.     

Book reviews

Sustainable Cities and Sustainable Development Sustainable Cities. G. Haughton & C. Hunter, 1994, Jessica Kingsley/Regional Studies Association, London

Sustainable Cities in Europe. P. Nijkamp & A. Perrels, 1994, Earthscan, London ISBN 185383, £12.95

Toward Sustainable Development Concepts, Methods and Policy. J. C. J. M. van den Bergh & J. van der Straaten, 1994, Island Press, Washington, DC, ISBN 1 55963 3492, £30.00

Just Environments: intergenerational, international and interspecies issues. David E. Cooper & Joy A. Palmer (Eds), 1995, London, Routledge, ISBN 0 415-10336-3, pp. 199, index, £11.99

First Steps: Local Agenda 21 in practice. Stella Whittaker (Ed.), 1995, London, HMSO, 251 pp. ISBN 0 11 701871 6, £29.95

Beyond the Car: essays on the auto culture. Sue Zielinski & Gordon Laird (Eds), 1995, Toronto, Steel Rail Publishing/Transportation Options, 191 pp. ISBN 0 88791 042 4, pbk, C$ 19.95, US$15.95     

Genotypic, size and morphological diversity of virioplankton in a deep oligomesotrophic freshwater lake (Lac Pavin, France)

We examined changes in morphological and genomic diversities of viruses by means of transmission electronic microscopy and pulsed field gel electrophoresis(PFGE) over a nine-month period(April–December 2005) at four different depths in the oligomesotrophic Lac Pavin. We found that the majority of viruses in this lake belonged to the family of Siphoviridae or were untailed, with capsid sizes ranging from 30 to 60 nm, and exhibited genome sizes ranging from 15 to 45 kb. On average, 12 different genotypes dominated each of the PFGE fingerprints. The highest genomic viral richness was recorded in summer(mean = 14 bands per PFGE fingerprint) and in the epilimnion(mean = 13 bands per PFGE fingerprint). Among the physico-chemical and biological variables considered, the availability of the hosts appeared to be the main factor regulating the variations in the viral diversity.