Use of the multispecies freshwater biomonitor to assess behavioral changes of Corophium volutator (Pallas, 1766) (Crustacea, Amphipoda) in response to toxicant exposure in sediment

Automated sediment toxicity testing and biomonitoring has grown rapidly. This study tested the suitability of the marine amphipod Corophium volutator (Pallas, 1766) for sediment biomonitoring using the Multispecies Freshwater Biomonitor (MFB). Two experiments were undertaken to (1) characterize individual behaviors of C. volutator using the MFB and (2) examine behavioral changes in response to sediment spiked with the pesticide Bioban. Four behaviors were visually identified (walking, swimming, grooming and falling) and characterized in the MFB as different patterns of locomotor activity (0-2 Hz range). Ventilation was not visually observed but was detected by the MFB (2-8 Hz). No clear diel activity patterns were detected. The MFB detected an overall increase in C. volutator locomotor activity after Bioban addition to the sediments (56, 100, 121 mg kg(-1)). C. volutator was more active (both locomotion and ventilation) in the water column than the spiked sediment. C. volutator appears a sensitive and appropriate species for behavioral sediment toxicity assessment and biomonitoring. (c) 2005 Elsevier Inc. All rights reserved.

Attitudes, norms, identity and environmental behaviour: Using an expanded theory of planned behaviour to predict participation in a kerbside recycling programme

In an effort to contribute to greater understanding of norms and identity in the theory of planned behaviour, an extended model was used to predict residential kerbside recycling, with self-identity, personal norms, neighbourhood identification, and injunctive and descriptive social norms as additional predictors. Data from a field study (N = 527) using questionnaire measures of predictor variables and an observational measure of recycling behaviour supported the theory. Intentions predicted behaviour, while attitudes, perceived control, and the personal norm predicted intention to recycle. The interaction between neighbourhood identification and injunctive social norms in turn predicted personal norms. Self-identity and the descriptive social norm significantly added to the original theory in predicting intentions as well as behaviour directly. A replication survey on the self-reported recycling behaviours of a random residential sample (N = 264) supported the model obtained previously. These findings offer a useful extension of the theory of planned behaviour and some practicable suggestions for pro-recycling interventions. It may be productive to appeal to self-identity by making people feel like recyclers, and to stimulate both injunctive and descriptive norms in the neighbourhood.

High-resolution 14C dating of a 25,000-year lake-sediment record from equatorial East Africa

We dated a continuous, ~22-m long sediment sequence from Lake Challa (Mt. Kilimanjaro area, Kenya/Tanzania) to produce a solid chronological framework for multi-proxy reconstructions of climate and environmental change in equatorial East Africa over the past 25,000 years. The age model is based on a total of 168 AMS 14C dates on bulk-organic matter, combined with a 210Pb chronology for recent sediments and corrected for a variable old-carbon age offset. This offset was estimated by i) pairing bulk-organic 14C dates with either 210Pb-derived time markers or 14C dates on grass charcoal, and ii) wiggle-matching high-density series of bulk-organic 14C dates. Variation in the old-carbon age offset through time is relatively modest, ranging from ~450 yr during glacial and late glacial time to ~200 yr during the early and mid-Holocene, and increasing again to ~250 yr today. The screened and corrected 14C dates were calibrated sequentially, statistically constrained by their stratigraphical order. As a result their constrained calendar-age distributions are much narrower, and the calibrated dates more precise, than if each 14C date had been calibrated on its own. The smooth-spline age-depth model has 95% age uncertainty ranges of ~50–230 yr during the Holocene and ~250–550 yr in the glacial section of the record. The d13C values of paired bulk-organic and grass-charcoal samples, and additional 14C dating on selected turbidite horizons, indicates that the old-carbon age offset in Lake Challa is caused by a variable contribution of old terrestrial organic matter eroded from soils, and controlled mainly by changes in vegetation cover within the crater basin.

Undecaprenyl phosphate recycling comes out of age

The recycling of the lipid carrier undecaprenyl-phosphate (Und-P) requires the dephosphorylation of Und-PP, a reaction proposed to occur at the external or periplasmic side of the bacterial cell membrane. In this issue of Molecular Microbiology, experiments based on the analysis of lipopolysaccharide modifications in Escherichia coli demonstrate that the phosphorylation of lipid A at position 1 is catalysed by the membrane enzyme LpxT (formerly YeiU). This enzyme specifically transfers the distal phosphate group from Und-PP to lipid A 1-phosphate to produce lipid A 1-diphosphate. Furthermore, this reaction requires a functionally intact MsbA protein, which catalyses the transfer of lipid A across the membrane, confirming that the LpxT-mediated lipid A modification occurs on the periplasmic side of the membrane. These observations provide a novel and unexpected link between periplasmic lipid A modifications and the Und-PP recycling pathway.