Restricted gene flow and evolutionary divergence between geographically separated populations of the Antarctic octopus Pareledone turqueti

Samples of the Antarctic octopus Pareledone turqueti were taken from three locations on the Scotia Ridge in the Southern Ocean. The genetic homogeneity of these populations was investigated using isozyme electrophoresis. Whilst panmixia appeared to be maintained around South Georgia (F _ST = 0) gene flow between this island and Shag Rocks, an island only 150 km away but separated by great depths, was extremely limited (F _ST = 0.74). These results are examined with respect to the discontinuous distribution of P. turqueti throughout Antarctica. An estimate of effective population size was also calculated (N _e = 3600). Received: 7 March 1997 / Accepted: 27 March 1997     

Environmental & economic life cycle assessment of current & future sewage sludge to energy technologies

The UK Water Industry currently generates approximately 800 GW h pa of electrical energy from sewage sludge. Traditionally energy recovery from sewage sludge features Anaerobic Digestion (AD) with biogas utilisation in combined heat and power (CHP) systems. However, the industry is evolving and a number of developments that extract more energy from sludge are either being implemented or are nearing full scale demonstration. This study compared five technology configurations: 1 – conventional AD with CHP, 2 – Thermal Hydrolysis Process (THP) AD with CHP, 3 – THP AD with bio-methane grid injection, 4 – THP AD with CHP followed by drying of digested sludge for solid fuel production, 5 – THP AD followed by drying, pyrolysis of the digested sludge and use of the both the biogas and the pyrolysis gas in a CHP.The economic and environmental Life Cycle Assessment (LCA) found that both the post AD drying options performed well but the option used to create a solid fuel to displace coal (configuration 4) was the most sustainable solution economically and environmentally, closely followed by the pyrolysis configuration (5). Application of THP improves the financial and environmental performance compared with conventional AD. Producing bio-methane for grid injection (configuration 3) is attractive financially but has the worst environmental impact of all the scenarios, suggesting that the current UK financial incentive policy for bio-methane is not driving best environmental practice. It is clear that new and improving processes and technologies are enabling significant opportunities for further energy recovery from sludge; LCA provides tools for determining the best overall options for particular situations and allows innovation resources and investment to be focused accordingly.     

Genetic variation and biochemical systematics in the marine bryozoan Alcyonidium mytili

For many years the taxonomic position of the marine ctenostome bryozoan Alcyonidium mytili Dalyell (1848) has been in doubt, with some authorities regarding it as being conspecific with A. polyoum (Hassall). We have set out to resolve this problem using enzyme electrophoresis to examine the genetics of the population structure in the two species. The results show beyond reasonable doubt that sympatric populations of the two species are indeed from quite separate and non-interbreeding gene pools. An examination of various allopatric populations shows a new species of A. mytili to exist sympatrically with the other at Langstone Harbour, Hampshire, England. This species can be readily distinguished on morphological as well as genetic ground. Samples of A. mytili from Guernsey also show substantial genetic differences from other populations examined. It is tentatively concluded that this population also represents a separate gene pool and consequently should be recognised as a third species of A. mytili.     

Effects of height and habitat type on egg parasitism by Trichogramma minutum and T. pretiosum (Hymenoptera: Trichogrammatidae)

Heliothis virescens (Fabricius) eggs were sampled to determine the effects of height and habitat type (soybean field vs. uncultivated vegetation) on rates of p arasitism by Trichogramma minutum Riley and T. pretiosum Riley. The potentially confounding effects of plant associations and host density and distribution were eliminated by sampling with laboratory-produced eggs deposited on cloths, rather than with eggs naturally deposited by endemic hosts.A 3-way contingency table analysis showed that parasitism (whether the egg cloths were parasitized or not) was significantly associated with height and habitat type in 1981, with higher rates of parasitism in the uncultivated habitat and at the greater height. Parasitism was independent of height and habitat in 1982. Rates of parasitism by the two Trichogramma species were not clearly associated with habitat type, but were associated with height. T. minutum consistently parasitized egg cloths positioned at greater heights than those parasitized by T. pretiosum. While the behavioral mechanisms responsible are unknown, this inter-specific difference could have important implications with regard to selecting the most suitable of these two Trichogramma species for a particular inundative release program.     

Control of Sitophilus oryzae infestation of stored wheat: An ecosystem model of the use of aeration

Populations of the grain storage insect pest Sitophilus oryzae (L.) may be controlled by manipulating the microclimates of grain bulks in which they occur. In this paper a validated mathematical model of the heat and moisture transfer phenomena that occur in aerated grain bulks is presented, and is combined with a population model of S. oryzae. The composite model predicts that blowing cold night air through grain bulks severely curtails the population growth of weevils. Furthermore, the composite model indicates that there is an optimum aeration strategy that results in the lowest number of insects. Aeration with ambient air is also shown to render the population dynamics of S. oryzae relatively insensitive to both initial grain moisture content and temperature. The results are discussed with reference to the physics of heat and moisture transfer between the air-water mixture and the hygroscopic grain.     

A Passive Sampler for Monitoring Urban Particulate: Preliminary Results

A passive sampling device, developed for personal monitoring of airborne dust levels in industry, has been tested as a site sampler in the urban environment. The device weighs approximately 15g and the essential sampling element is a small disc of electret material (polymer carrying a permanent electric charge). During use it captures particles by electrical attraction, at a rate that depends upon their electrical mobility, but which is independent of the rate at which air flows past the sampler. It collects measurable quantities of particulate, though the sample size tends to be small and correlation with results from conventional samples has not yet been established. Samplers have been exposed to urban particulate for periods of up to seven days, without the electret suffering unacceptable loss of electric charge. It has been shown to be potentially useful for long-term monitoring, a situation in which dispensing with a power source is particularly useful. Being small, the passive sampler is easy to hide or camouflage. It has potential for multiple simultaneous site sampling and for monitoring personal environmental exposure.     

Seasonal changes in the diet and feeding behaviour of a top predator indicate a flexible response to deteriorating oceanographic conditions

Shifts in the diet of top predators can be linked to changes in environmental conditions. In this study, we tested relationships between environmental variation and seasonal changes in diet of a top predator, the grey-headed albatross Thalassarche chrysostoma, breeding at Bird Island, South Georgia in an austral summer of 1999/2000. Oceanographic conditions in that year around South Georgia were abnormal (i.e. anomalously high sea surface temperature to a relative 19-year long-term mean). The diet of grey-headed albatrosses showed high seasonal variation, shifting from cephalopods (42.9 % by mass) in late February to Antarctic krill Euphausia superba (58.3 %) in late April, and grey-headed albatrosses breeding performance was low (16.8 %). This study shows these albatrosses did not manage to find sufficient alternative prey and highlight the risk to top predators if there is an increase in the frequency or severity of food shortages in Antarctic waters.     

Tracking the Debate Around Marine Protected Areas: Key Issues and the BEG Framework

Marine conservation is often criticized for a mono-disciplinary approach, which delivers fragmented solutions to complex problems with differing interpretations of success. As a means of reflecting on the breadth and range of scientific research on the management of the marine environment, this paper develops an analytical framework to gauge the foci of policy documents and published scientific work on Marine Protected Areas. We evaluate the extent to which MPA research articles delineate objectives around three domains: biological-ecological [B]; economic-social[E]; and governance-management [G]. This permits us to develop an analytic [BEG] framework which we then test on a sample of selected journal article cohorts. While the framework reveals the dominance of biologically focussed research [B], analysis also reveals a growing frequency of the use of governance/management terminology in the literature over the last 15 years, which may be indicative of a shift towards more integrated consideration of governance concerns. However, consideration of the economic/social domain appears to lag behind biological and governance concerns in both frequency and presence in MPA literature.     

Genetic divergence between colour morphs in populations of the common intertidal sea anemones Actinia equina and A. prasina (Anthozoa: Actiniaria) in the Isle of Man

A distinctive morph ofActinia equina (L.) is found at low frequency among populations on intertidal hard substrata on some shores on the Isle of Man. This morph is red with rows of green oval spots or elongate markings running longitudinally down the column. Starch gel electrophoresis of 21 allozyme loci was used to compare samples of this morph from two localities with other sympatricActinia spp. Collections were made in early summer 1986. For one sampling site the comparison was with redA. equina and greenA. prasina Gosse, whilst at the other site with redA. equina only. At both sites significant genetic differences in allele frequencies at several loci were found between the new morph and sympatricA. equina andA. prasina. The results also confirm the reproductive isolation ofA. prasina. As with much previous work on sea anemones, levels of mean heterozygosity per locus (H) were found to be high (H=0.157 to 0.342). A surprising feature of the results, although bearing out earlier unpublished data, is that high levels of genetic differentiation are found between populations of what appear to be the same morphs collected from shores only a few km apart. Among theActinia spp. studied, differentiation between populations of the same morph on different shores was of the same order as between sympatric, reproductively isolated populations.