Anthropogenic disturbance of deep-sea megabenthic assemblages: a study with remotely operated vehicles in the Faroe-Shetland Channel,NE Atlantic

The effects of local-scale anthropogenic disturbance from active drilling platforms on epibenthic megafaunal abundance, diversity and assemblage pattern were examined in two west of Shetland hydrocarbon fields at 420 and 508 m water depth. These areas were selected to include a range of disturbance regimes and contrasting faunal assemblages associated with different temperature regimes. Remotely operated vehicle (ROV) video provided high-resolution megafaunal abundance and diversity data, which were related to the extent of visible disturbance from drilling spoil. These data, in conjunction with a study deeper in the Faroe-Shetland Channel, have allowed comparison of the effects of disturbance on megabenthos across a range of sites. Disturbance to megafaunal assemblages was found to be high within 50 m of the source of drill spoil and in areas where spoil was clearly visible on the seabed, with depressed abundances (Foinaven 1,900 individuals ha⁻¹; Schiehallion 2,178 individuals ha⁻¹) and diversity (H′ = 1.75 Foinaven; 1.12 Schiehallion) as a result of smothering effects. These effects extended to around 100 m from the source of disturbance, although this was variable, particularly with current regime and nature of drilling activity. Further from the source of disturbance, megafaunal assemblages became more typical of the background area with increased diversity (H′ = 2.02 Foinaven; 1.77 Schiehallion) and abundance (Foinaven 16,484 individuals ha⁻¹; Schiehallion 5,477 individuals ha⁻¹). Visible effects on megafaunal assemblages as a result of seabed drilling were limited in extent although assemblage responses were complex, being controlled by differing effects to individual species often based on their motility.     

Polynuclear aromatic hydrocarbons in crops from long-term field experiments amended with sewage sludge

This study reports on the polynuclear aromatic hydrocarbon (PAH) content of crop plants grown at three different field experiments where controlled additions of sewage sludge were made a number of years ago. Archived samples of several crops have been analysed from sludge-amended and unsludged control plots for 15 PAH compounds. Root crops and above ground plant parts were available for several years following the last applications of sludge. Although the soil PAH burden increased substantially due to sewage sludge additions, and residues of these compounds have persisted in the soils for many years, increased PAH concentrations relative to the unsludged controls were not consistently detected in plant tissues. Plant samples were relatively enriched with low molecular weight compounds such as acenaphthene/fluorene nd phenanthrene. Various lines of evidence indicate that PAHs detected in above ground plant parts are chiefly derived from atmospheric inputs, while PAHs detected in root crops probably arise from adsorption to the root surface.     

Relatedness structure and kin-biased foraging in the greater horseshoe bat (Rhinolophus ferrumequinum)

Female greater horseshoe bats (Rhinolophus ferrumequinum) exhibit strong natal philopatry to their maternity roost over many years, leading to the aggregation of matrilineal kin. Maternity colonies may, therefore, be expected to comprise highly related individuals, and, as such, provide conditions suitable for the evolution of kin-selected behaviours. To test these predictions, we examined relatedness and behaviour among matrilineal kin within a colony in south-west Britain. Genetic analysis of 15 matrilines, identified from microsatellite genotyping and long-term ringing surveys, revealed average relatedness levels of 0.17 to 0.64. In contrast, background relatedness among colony females approximated to zero (0.03). These results suggest that inclusive fitness benefits may only be accrued through discriminate cooperation within matrilines, and not at the wider colony level. To examine whether the potential for such benefits is realised through kin- biased cooperation during foraging, females from two matrilines were radio-tracked simultaneously over 3 years. Pairwise home-range overlap correlated significantly with Hamilton's relatedness coefficient. The greatest spatial associations were observed between females and their adult daughters, which shared both foraging grounds and night roosts, sometimes over several years. Tagged females, however, generally foraged and roosted alone, suggesting that kin-biased spatial association probably does not result from either information-transfer or cooperative territorial defence. Such patterns may instead result from a mechanism of maternal inheritance of preferred foraging and roosting sites.     

Stable isotopic investigation of physiological and environmental changes recorded in shell carbonate from the giant clam Tridacna maxima

The aragonitic shell of the photosymbiont-bearing bivalve Tridacna maxima contains a record of the physiological and environmental changes the organism has experienced during its lifetime. This record is preserved as chemical and microstructural variations throughout the shell. Stable isotopic analyses of oxygen (¹⁸O/¹⁶O) and carbon (¹³C/¹²C) in shell carbonate were combined with growth increment studies to interpret the shell record of specimens collected from the Rose Atoll (Lat. 14°31S; Long. 168°10W) in April 1982. The seasonal water temperature cycle is recorded in the oxygen isotopic signature of the clams, permitting the recognition of annual cycles in the ¹⁸O profile. The total number of these cycles corresponds to the age of a specimen, while the cycle length is a measure of the yearly growth rate. Large-amplitude cycles, reflecting year-round calcification, characterize the early portion of the growth record. With the onset of sexual maturity and slower growth at an age of approximately ten years, the cycles decrease in amplitude and become more erratic. During this later growth phase calcification is limited to the cooler months of the year, perhaps in response to a re-ordering of energy priorities between growth and gametogenesis. A growth curve developed from the ¹⁸O profile indicates rapid juvenile shell growth followed by slower growth thereafter producing a lifespan of several decades. Carbon isotopic analyses of T. maxima were compared to analyses of the symbiont-barren gastropod Terebra areolata collected from the same locality in April 1984. A 2 depletion in the ¹³C composition of T. maxima shell carbonate is attributed to a symbiontenhanced metabolic rate and an increased flow of isotopically light, respired CO₂ into the carbon pool used in calcification. Such a depletion may prove useful in identifying the presence of photosymbionts in extinct species of fossil mollusks.     

PAHs associated with the leaves of three deciduous tree species. I--Concentrations and profiles

Results for the concentrations of total polycyclic aromatic hydrocarbons (Sigma PAH) and the PAH profile in leaves from three deciduous tree species from the same woodland are presented, and discussed with reference to environmental and leaf-related variables. There were significant differences between oak, ash and hazel leaves in their Sigma PAH concentrations (sum of 23 PAHs), and in the relative contribution of individual PAHs to the sum. Leaves exhibiting pubescence (hairiness) were found to have significantly higher Sigma PAH concentrations than hairless leaves, regardless of their position in the vegetation strata of the wood. Hazel leaves from the understorey had a PAH profile consisting of a greater proportion of the 4-, 5- and 6-ring PAHs than oak or ash from the canopy. This was concluded to be the result of the filtering effect of the main canopy on the air passing over and through it, with subsequent transfer of particles and attendant PAHs to the understorey below. The proportion of Sigma PAH contributed by the 6-ring PAH in hazel leaves was negatively correlated with distance from the southern edge of the canopy. It is proposed that the predominantly windward edges of the woodland, where atmospheric turbulence is likely to be greatest, favoured the deposition of particle-bound PAHs to leaves.     

An approach for assessment of water quality using semipermeable membrane devices (SPMDs) and bioindicator tests

As an integral part of our continued development of water quality assessment approaches, we combined integrative sampling, instrumental analysis of widely occurring anthropogenic contaminants, and the application of a suite of bioindicator tests as a specific part of a broader survey of ecological conditions, species diversity, and habitat quality in the Santa Cruz River in Arizona, USA. Lipid-containing semipermeable membrane devices (SPMDs) were employed to sequester waterborne hydrophobic chemicals. Instrumental analysis and a suite of bioindicator tests were used to determine the presence and potential toxicological relevance of mixtures of bioavailable chemicals in two major water sources of the Santa Cruz River. The SPMDs were deployed at two sites; the effluent weir of the International Wastewater Treatment Plant (IWWTP) and the Nogales Wash. Both of these systems empty into the Santa Cruz River and the IWWTP effluent is a potential source of water for a constructed wetland complex. Analysis of the SPMD sample extracts revealed the presence of organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The bioindicator tests demonstrated increased liver enzyme activity, perturbation of neurotransmitter systems and potential endocrine disrupting effects (vitellogenin induction) in fish exposed to the extracts. With increasing global demands on limited water resources, the approach described herein provides an assessment paradigm applicable to determining the quality of water in a broad range of aquatic systems.     

Influence of plants on the chemical extractability and biodegradability of 2,4-dichlorophenol in soil

This study investigated the fate and behaviour of [UL-(14)C] 2,4-dichlorophenol (DCP) in planted (Lolium perenne L.) and unplanted soils over 57 days. Extractability of [UL-(14)C] 2,4-DCP associated activity was measured using calcium chloride (CaCl(2)), acetonitrile-water and dichloromethane (DCM) extractions. Biodegradability of [UL-(14)C] 2,4-DCP associated activity was assessed through measurement of (14)CO(2) production by a degrader inoculum (Burkholderia sp.). Although extractability and mineralisation of [UL-(14)C] 2,4-DCP associated activity decreased significantly in both planted and unplanted soils, plants appeared to enhance the sequestration process. After 57 days, in unplanted soil, 27% of the remaining [UL-(14)C] 2,4-DCP associated activity was mineralised by Burkholderia sp., and 13%, 48%, and 38% of (14)C-activity were extracted by CaCl(2), acetonitrile-water and DCM, respectively. However, after 57 days, in planted soils, only 10% of the [UL-(14)C] 2,4-DCP associated activity was available for mineralisation, whilst extractability was reduced to 2% by CaCl(2), 17% by acetonitrile-water and 11% by DCM. This may be due to the effect of plants on soil moisture conditions, which leads to modification of the soil structure and trapping of the compound. However, the influence of plants on soil biological and chemical properties may also play a role in the ageing process.     

Determination of fluoroquinolone antibiotics in wastewater effluents by liquid chromatography-mass spectrometry and fluorescence detection

The occurrence of quinolone antibiotics (QAs) was investigated in wastewater effluents and surface river/lake waters in the US and Canada by using solid-phase extraction with mixed phase cation exchange disk cartridge and liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography fluorescence detection (LC-FLD). Ofloxacin (OFL) was detected in secondary and final effluents of a wastewater treatment plant (WWTP) in East Lansing, Michigan, at concentrations of 204 and 100 ng/l, respectively. The mass flow calculation, estimated by multiplying the OFL concentration in the final effluent by the average influent volume of the WWTP, showed that the discharge of OFL to the river was 4.8 g/day. The OFL concentrations in wastewater effluents measured in this study are comparable to or less than those observed in several European countries. QAs were not detected in river and lake waters analyzed in this study, which may due to dilution effects and to the higher detection limits, relative to those reported previously. OFL concentrations were approximately 1-2 orders of magnitude lower than the EC50 concentrations for environmental bacterium. However, greater concentrations of other QAs in sewage sludge from WWTPs may result in cumulative effects. Considering that the sewage sludge is applied to the land as fertilizers, soil-dwelling organisms could experience greater exposures to such antibiotics. Monitoring studies of QAs in sewage from WWTPs and in sediment/soil near aquaculture facilities and livestock farms will be necessary for the evaluation of the environmental distribution and risk of these compounds.