Growth and longevity in the crustose red algaPetrocelis middendorffii

Petrocelis middendorffii is a non-calcareous encrusting red alga growing on rocks in the middle and upper intertidal zone. We have photographically followed the fate of 43 individual plants for periods up to 88 months at Waadah Island, near Neah Bay, Washington (USA). Growth is slow, with surface area increasing about 4% year^-1 for those individuals growing. Other plants were observed to decrease in total surface coverage, fragment, and eventually disappear. Plants on neighboring but not contiguous sample sites are not in synchrony, with some subpopulations increasing their total space coverage while others diminished theirs. Age estimates, based on a variety of growth interpretations, suggest that an average sized individual (123 cm²) will be from 25 to 87 years old. Recruitment and mortality rates appear low. The ecological traits ofP. middendorffii may be similar to those of other crustose heteromorphic benthic algae.     

FADs influence on settlement and dispersal of the young-of-the-year greater amberjack (<Emphasis Type="Italic">Seriola dumerili</Emphasis>)

FADs are fish aggregating devices applied worldwide over the centuries to increase fish catch. However, the utilisation of such floating devices can influence dispersion patterns of some fish species. At present it is still not clear if FADs play a role in the shoreward migrations of juvenile fish of reef associated species, such as the greater amberjack Seriola dumerili. In this study, we hypothesised that FADs located along a distance gradient from the shore might lead the greater amberjack inshore. In such case, mean abundance of S. dumerili should decrease over time in offshore FADs and increase in inshore FADs. To test the hypothesis three FAD systems were positioned in the Gulf of Castellammare (Sicily, Italy), between July and September 2001, at increasing distances from the coast. During the study period, five visual censuses were carried out within FADs fields. During the first sampling period, no significant difference in abundance and size of juvenile S. dumerili was found between the three FAD systems. All the other sampling periods reported higher abundances and sizes in the offshore FADs than in the two inshore FADs. The findings suggest that FAD systems might be exerting two different effects on young of the year (YOY) S. dumerili distribution: (a) offshore FADs tend to retain associated fish for longer periods of time, (b) coastal FADs favour the transition of YOY S. dumerili from the pelagic to the benthic domain.     

Individual variation and prior experience affect the discrimination of a brood-parasite by its subsocial beetle host

In birds, host experience can modify response to parasites but nothing similar is known for insects. We studied two desert tenebrionid beetles, the subsocial host Parastizopus armaticeps and its obligate and ubiquitous brood-(clepto)parasite Eremostibes opacus, which mimics the hosts odour spectrum. Nearly 10% of host burrows in the field (n=214) remain unparasitised even after introducing E. opacus experimentally (n=22). In discrimination tests, 7% of naive host beetles eject the parasite, showing individual variation in olfactory discrimination ability. To test for effects of prior breeding experience, naive (first time) or experienced (second time) breeders with or without prior parasite contact were confined with E. opacus at breeding onset, their behaviour recorded and parasite number counted on breeding completion. More first- than second-time breeding pairs completely excluded the parasite and second-time breeders with no prior contact with E. opacus had fewer parasites than any others. These pairs increased burrow-guarding dramatically, mostly during early reproduction, this being the best predictor of parasite number. Prolonged guarding, however, must be traded-off against other brood-care behaviours. Hence, it might pay breeding pairs to take the risk of accepting some parasites breeding within their burrow, and we expect this effect will be more pronounced if poor feeding and digging conditions are taken into account. This might explain why apparently 90% of the P. armaticeps breeding burrows in the field contain at least one parasitic E. opacus.Communicated by D. Gwynne     

Levels of organochlorine pesticide residues in marine-, surface-, ground- and drinking waters from the Eastern Cape Province of South Africa

Persistent organochlorine pesticides (OCPs) such as DDT and its metabolites (DDDs and DDEs). chlordane, hexachlorobenzene (HCB), heptachlor and endosulfan were determined in drinking-, ground-, surface- and marine waters from the Eastern Cape Province of South Africa. Percentage recoveries of the OCPs from spiked river water ranged from 71.03 +/- 8.15% (dieldrin) to 101.25 +/- 2.17% (alpha-BHC). The levels of OCPs ranged from 5.5 ng/L (2,4-DDD) to 160 ng/L (HCB) in the water samples. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulfan and chlordane were detected.     

Sorbent-assisted liquid-liquid extraction (Chem-Elut) of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in the lipid fraction of human blood plasma

This work compares two lipid extraction methods for determining 24 polychlorinated biphenyls (PCBs), seven dibenzo-p-dioxins (PCDDs) and ten dibenzofurans (PCDFs) in human blood plasma. The first method was based on conventional liquid-liquid partitioning with chloroform-methanol and the other made use of a sorbent (Chem-Elut) to facilitate the partitioning of lipids into a mixture of hexane and 2-propanol. A multi-layer-silica column including acid- and base-impregnated silica gel was used to reduce the amounts of lipid present in the samples before a basic alumina clean-up step and activated carbon fractionation of planar analytes (PCDD/Fs and non-ortho-PCBs) and non-planar analytes (including ortho-chlorinated PCBs). Gas chromatography coupled to high resolution mass spectrometry was used to identify and quantify the analytes in the two fractions. The wet weight based concentrations obtained by the two methods were in agreement but both methods suffer from large organic solvent consumption. The toxic equivalencies derived for PCBs and PCDD/Fs using the two methods were also in agreement. However, the chloroform-methanol method gave slightly higher lipid recoveries, although with greater variation, than the sorbent-assisted method. Nevertheless, despite giving lower lipid recoveries, the sorbent-assisted method has advantages in ease of use and applicability to whole blood samples. The formation of emulsions was avoided with the Chem-Elut method, which probably explains the lower variability in the lipid determinations.     

Evaluating multimedia/multipathway model intake fraction estimates using POP emission and monitoring data

This paper presents a structured evaluation of a novel multimedia chemical fate and multi-pathway human exposure model for Western Europe, IMPACT 2002, using data for PCDD/F congeners. PCDD/F congeners provide an illustration of the potential use of POPs (Persistent Organic Pollutant) data for the evaluation of such models. Based on available emission estimates, model predictions with and without spatial resolution are evaluated at three different stages against monitored data: at environmental contamination levels, food exposure concentration, and in terms of human intake fractions (iF): the fraction of an emission that is taken in by the population. The iF is approximately 3.5.10(-3) for emissions of dioxin in Western Europe. This iF compares well to the traditional non-spatial multi-media/-pathway model predictions of 3.9.10(-3) for the same region and to 2.10(-3) for the USA. Approximately 95% of the intake from Western European emissions occurs within the same region, 5% being transferred out of the region in terms of food contaminants and atmospheric advective transport.     

Monitoring of persistent organic pollutants (POPs): examples from Lake Vättern, Sweden

Lake V?ttern in southern Sweden is a large oligotrophic lake with high surface to catchment area ratio (ca. 0.4) and a water residence time of 60 years. The lake combines sensitivity to atmospheric POP-pollution with general susceptibility for effects of POPs and slow concentration decline. Time series, from the 1960s until 1996, of PCBs and DDT in fish and data on TCDD in sediment of L. V?ttern are presented and compared to other large lakes. The long time dataset of POPs in Arctic char (Salvelinus salvelinus) shows a significant annual decline of about 5% for PCBs and 13% for DDT. These rates are in agreement with other studies. Nutrients as well as biological effects and factors affecting the fate of POPs in oligotrophic lakes with long residence times are discussed. We propose that oligotrophic clear lakes are important ecosystems for monitoring POPs in biota.     

Soviet and post-Soviet environmental management: lessons from a case study on lead pollution

Through a case study on lead pollution in the former Soviet Union, the linkage of policy, environmental science, and environmental management is explored, and compared with the US experience. Soviet bans on leaded gasoline and lead-based paint appear to have been effective. Regional governments, in cooperation with the petroleum industry, are taking the initiative in phasing out leaded gasoline, to some extent in defiance of federal policy. Problems with management of lead-acid batteries have been worsened by the collapse of the political system. Lack of reliable environmental data impedes reliable environmental assessment. The types of environmental measurements reflect an emphasis on multipollutant environmental contamination, rather than on human exposure to single pollutants.     

Effect of boiler operation and RDF feedstock on emissions of dioxins and furans from an RDF fired sp reader-stoker system in Albany, NY

The data on dioxin and furan emissions revealed, based on individual analysis for 2,3,7,8-TCDD, TCDD, 2,3,7,8-TCDF and TCDF for the six test periods and the operation of the two RDF-fired boilers, that there is no apparent consistent relationship between the dioxin and furan emissions and the individual or combined (averaged) boiler steam flow, total flue gas flow, sidewall furnace temperature, furnace temperature at 2-second residence time, or total furnace residence time at this plant. Only RDF feeder balance begins to show a correlation. However, there was a difference between RDF-natural gas firing and RDF-only firing; the RDF-only firing had lower PCDD and PCDF emissions while consistently operating at lower excess air.

The dioxin and furan emissions from this testing are comparable to the low end of the range of these emissions measured by the U.S. EPA at resource recovery plants in the past 4 years. This may be due in part to the calculated average furnace retention of 4 to 5 seconds during Tests #4–6, with average furnace temperatures at 2-second residence time from 1650°F to 1750°F. However, there was no correlation between dioxin and furan emissions in the stack and individual boiler operation, as judged by the average concentrations of O₂, CO, CO₂, 1-CO/CO₂), NO_x, HCl, SO₂, or TSP, and furnace upset conditions versus normal operation as judged by instantaneous steam flow, sidewall furnace temperature, O₂, CO, NO_x, or SO₂.