Seasonal concentrations and partitioning of PAHs in a suburban site of Bursa, Turkey

Effects of space heating on atmospheric concentrations and gas-particle partitioning of PAHs were investigated in a suburban site of Bursa, Turkey. The average concentrations of ∑₁₅-PAHs in heating season samples were approximately 10 times higher than those of non-heating season samples. The plot of log K_p versus log P_L⁰ for all the data set gave significantly different slopes. The slope for the heating season (−0.75) samples was steeper than the one for the non-heating season (−0.64) samples. It was also observed that partitioning of PAHs for the non-heating season samples showed different characteristics depending on air parcel trajectories. Generally steeper slopes were obtained for the air parcels traveled across the Black sea and arrived to the sampling site from northern sector. On the other hand, the variations in slopes according to air mass origin were insignificant for the heating season samples. Local contributions from space heating are the reason for this observation.     

Characterizing effects of uncertainties in MSW composting process through a coupled fuzzy vertex and factorial-analysis approach

A coupled fuzzy vertex and factorial-analysis approach was developed in this study for systematically characterizing effects of uncertainties in a municipal solid waste composting process. A comprehensive composting process model was also embedded into the system framework and used to address substrate decomposition and biomass growth, as well as the interactions between moisture contents, temperatures, and oxygen concentrations. The applicability of the proposed method was verified through a custom-made pilot-scale composting system. Results from fuzzy simulation indicated that the fuzzy vertex method could effectively communicate implicit knowledge into dynamic simulations and thus provide valuable information for enhancing composting process control under uncertainty. The factorial analysis was effective in quantifying the proportion to which the uncertainty of each single or interactive effect of model parameters contributes to the overall uncertainty of the system outcomes. Thus, sensitive parameters that may lead to errors or unreasonable predictions can be determined. The proposed study system could not only be used in characterizing combined effects of uncertainties for composting processes, but was also applicable to many other environmental modelling systems.     

Multiple song repertoire characteristics in the willow warbler (Phylloscopus trochilus): correlations with female choice and offspring viability

Male willow warblers have song repertoires which vary in complexity along several dimensions. We examined whether female choice, as measured by date of pairing, was based on these song characteristics in 4 different years. Pairing date was negatively correlated with song repertoire size in 1 year, and with song versatility in another year, but there was no consistent effect of any song characteristic on pairing throughout the years or in the pooled sample. The variable that best explained how soon a male pairs is male arrival date (only males that had settled territories before the first female arrived were considered in the analysis). This correlation is consistently significant in all years. This is most parsimoniously interpreted as females choosing some habitat characteristic in the same way that males do. A small percentage of males (8.3%) attracted and paired with a second female. The likelihood of becoming polygynous was not explained by any measured song characteristic, but it was related to arrival date: early males were more likely to pair with two females. Males with large repertoires fledged more young in their primary nests, and there was a trend for the offspring of these males to have a greater probability of being recruited into the population. In conclusion, the results show that in most years there is no sexual selection by female preference on song characteristics, although the data on reproductive success is consistent with the idea of repertoire size being an indicator of male quality. Received: 4 June 1999 / Received in revised form: 1 December 1999 / Accepted: 31 December 1999     

Assessing the Geographic Representativeness of Genebank Collections: the Case of Bolivian Wild Potatoes

Abstract: Genebank collection databases can be used for ecogeographical studies under the assumption that the accessions are a geographically unbiased sample. We evaluated the representativeness of a collection of wild potatoes from Bolivia and defined and assessed four types of bias: species, species-area, hotspot, and infrastructure. Species bias is the sampling of some species more often than others. Species-area bias is a sampling that is disproportionate to the total area in which a species is found. Hotspot bias is the disproportionate sampling of areas with high levels of diversity. Infrastructure bias is the disproportionate sampling of areas near roads and towns. Each of these biases is present in the Bolivian wild potato collection. The infrastructure bias was strong: 60% of all wild potato accessions were collected within 2 km of a road, as opposed to 22%, if collections had been made randomly. This analysis can serve as a guide for future collecting trips. It can also provide baseline information for the application of genebank data in studies based on geographic information systems.     

Parthenogenetic reproduction of Diaphanosoma celebensis (Crustacea: Cladocera): influence of salinity on feeding, survival, growth and neonate production

 Effect of salinity on the feeding rate and parthenogenetic reproduction of asexual females of the cladoceran Diaphanosoma celebensis Stingelin was studied. Short-term (10 h) grazing experiments were conducted using Isochrysis galbana as feed at 5, 17, 25 and 30 psu salinity. Gut pigment concentration showed a significantly higher rate of feeding at lower salinities. Survival, growth, maturity attainment and neonate production of asexual females reared in the above four test salinities indicated preference for lower salinities (5 and 17 psu). The mean size of adult females decreased from 909 to 593 μm, mean life span from 24 to 5 d, mean neonate production from 12 to 2 and mean size of neonates from 434 to 400 μm as the salinity increased from 5 to 30 psu. Salinity variations also affected the size and age of primiparous females. Resting egg formation and sexual reproduction did not occur at the tested salinities. The results indicate that D. celebensis is adapted to low saline, estuarine environments. Received: 14 January 2000 / Accepted: 24 March 2000     

Grazing rates of organic matter and living fungal biomass of decaying Spartina alterniflora by three species of salt-marsh invertebrates

 The pathway for the flow of salt-marsh grass production into marsh food-webs is still not well defined. We compared the abilities of three marsh macroinvertebrates [salt marsh periwinkles, Littoraria irrorata (Say) (=Littorina irrorata), salt-marsh coffee-bean snails, Melampus bidentatus (Say); and a talitrid amphipod, Uhlorchestia spartinophila Bounsfield and Heard] to access standing-dead leaves of smooth cordgrass (Spartina alterniflora Loisel). The invertebrates were incubated with naturally-decaying leaves, and the rates of removal of organic matter and living fungal biomass (ergosterol) were measured. The impact of invertebrate activity upon fungal growth rates was measured as rates of fungal-membrane synthesis (incorporation of radioacetate into ergosterol). The removal rates of organic leaf biomass per mg individual biomass were highest for amphipods (700 μg mg⁻¹ d⁻¹) and lowest for periwinkles (90 μg mg⁻¹ d⁻¹), but the relatively large biomass of the snails made their removal rates per individual greater than those of amphipods. Net removal of ergosterol by all three invertebrates was >50% for yellow-brown (early-decay) leaf blades. For fully-brown (advanced-decay) blades, >50% removal of ergosterol was found only for periwinkles; exposure to coffee-bean snails and amphipods resulted in a net ergosterol reduction of ≤20%. The lower net reduction of living fungal biomass by coffee-bean snails and amphipods may have been due to fungal-growth stimulation (2.3-fold stimulation in coffee-bean snails and 1.5-fold stimulation in amphipods). Grazing by periwinkles did not stimulate fungal growth, possibly because of its high intensity. Grazing by these three salt-marsh shredders may affect marsh-grass shoot-decay in different ways. Periwinkles may abbreviate the period of fungal production, and incorporate the decaying material relatively quickly into snail biomass and fecal-pellet rain to the sediments. Coffee-bean snails and amphipods may enhance and prolong fungal production, along with the formation of fecal-pellet rain. All three invertebrates fed preferentially on leaf blades rather than leaf sheaths, and feeding rates of gastropods were higher during the night than during the day. Received: 25 November 1998 / Accepted: 4 November 1999     

Size-related aspects of arm damage, tissue mechanics, and autotomy in the starfish Asterias rubens

 Arm damage is a widely reported but superficially investigated aspect of the biology of the starfish Asterias rubens L. In the present study, the incidence of arm damage was surveyed in populations of A.  rubens at two sites in the Firth of Clyde, Scotland, and three sites in Gullmarsfjorden, Sweden. The mean (±SD) incidence across all sites of individuals with basal arm damage (resulting from detachment at the basal autotomy plane) was 19.69 ± 8.86%, the incidence of those with distal arm damage (resulting from amputation at more distal levels) was 7.74 ± 10.01%. The mean incidence of arms with basal damage was 5.28 ± 4.12%, of those with distal damage 1.83 ± 2.45%. There was a significant negative correlation between size and the incidence of basal damage at all but one site, but no significant correlation between size and distal damage at any site. Mechanical tests on specimens of the aboral body wall from the basal region of the arm (which included the autotomy plane) and from a more distal region revealed that with increasing body size there was a significant increase in yield stress, ultimate stress and Young's modulus (stiffness) but no significant change in yield strain and ultimate strain. There was no significant difference between the relationships for basal and distal specimens. It is hypothesised that in larger individuals increased mechanical toughness replaces autotomy as an effective antipredator strategy. Using two methods to induce autotomy, a significant positive correlation between size and the delay between the onset of stimulation and arm detachment was found; this may represent a size-related decline in the efficiency of the autotomy mechanism through the relaxation of selection pressure. Since size is an unreliable indicator of age in A.  rubens, the trends identified herein can be interpreted only tentatively as age-associated phenomena. Received: 4 September 1999 / Accepted: 17 February 2000     

Metabolic differences between “demersal” and “pelagic” development of the Antarctic sea urchin Sterechinus neumayeri

 Early development of the Antarctic sea urchin Sterechinus neumayeri was examined under two differ-ent culture regimes: one to simulate development near-bottom (“demersal development”) and the other to simulate the development of embryos in the water column (“pelagic development”). When embryos of both treatments reached the hatching blastula stage at 5 d post-fertilization (−1.5 °C), the blastulae that had undergone demersal development evidenced significant differences (by ANOVA or suitable non-parametric comparison) in the following: a thicker blastoderm layer (12%, P < 0.001), higher ash-free dry weights (19%, P < 0.01), lower mass-specific respiration rates (50%, P < 0.001), higher incorporation rates of ³⁵S-methionine into protein (23%, P < 0.003), and a differential pattern of protein synthesis. When embryos developed demersally, they remained in the jelly-coat material released with the eggs at spawning. Quantitative isolation of this jelly-coat material in S. neumayeri demonstrated that it contained a significant amount of organic matter, 115 ng ash-free dry mass per egg, equivalent to 17% of the egg's initial organic mass. Uptake of external nutrients during embryogenesis may be a significant component of the physiological energetics of this polar invertebrate by allowing the utilization of jelly-coat material released by a female during spawning. Received: 21 April 1999 / Accepted: 5 June 2000     

Short retention times of stomach temperature loggers in free-living seabirds: is there hope in the spring?

Stomach temperature loggers have proved useful for the study of feeding activity in free-living seabirds, but their usage has been restricted because they are frequently dislodged and lost during the seabirds' regular regurgitation of indigestible prey remains. In the present study we examine the incidence of spontaneous regurgitation (pellet production) in free-living seabirds, consider the effect this has on the likely retrieval of stomach temperature loggers and present a structural modification of the logger housings which leads to a much lower incidence of regurgitation. Systems were tested on albatrosses, cormorants, gannets and penguins. Received: 15 July 1997 / Accepted: 31 October 1997     

Recovery of benthic communities at Macquarie Island (sub-Antarctic) following a small oil spill

Intertidal communities at Macquarie Island (sub-Antarctic) were re-evaluated seven years after a small oil spill resulting from the grounding of the “Nella Dan”, and six years after the first assessment of biological impact. Sampling was conducted to evaluate community structure in three zones of the exposed rocky shore (upper red, kelp, and lower red) and in samples of Durvillaea antarctica holdfasts. There were no significant differences between the community structure in oiled and control locations in any of the three shore zones, but holdfast macrofaunal communities at oiled sites still showed evidence of impact. Holdfast community-structure in samples from heavily oiled sites showed moderate levels of recovery, with increased abundances of species which were considered sensitive to the oiling in the first post-impact studies and decreased abundances of opportunistic polychaete and oligochaete worms. In contrast, samples collected from the moderately oiled location at Secluded Bay showed little evidence of recovery. Holdfasts at this site were filled with sediment containing traces of diesel oil, and the macrofaunal community was dominated by opportunistic worms. This study clearly indicates that even small incidents of anthropogenic perturbation can have long-lasting consequences for marine communities at Macquarie Island. Received: 23 July 1997 / Accepted: 5 February 1998