Quantity and biochemical composition of sedimentary organic matter around offshore gas extraction platforms of the Adriatic Sea

Gas platforms can exert relevant effects on various ecosystem properties of the hosting area, modifying patterns of productivity and particle sedimentation. We hypothesised that the presence of gas platforms is associated with higher organic matter (OM) contents and we tested the null hypothesis by which benthic trophic conditions do not vary significantly among gas structures with different architectural characteristics. To test these hypotheses, we investigated sedimentary OM contents and biochemical composition at increasing distance from two distinct structures: one subsea well-site and one four-leg platform (FLP). We found that sediments surrounding the structures were characterised by similar OM contents, but different biochemical compositions, and that sedimentary OM compositional change with increasing distance from the structure is confirmed only at the FLP. These results suggest that: (i) benthic eutrophication is not consistent among different structures; (ii) OM biochemical composition changes are more evident than those in OM quantity; and (iii) the effect, wherever present, disappears at a very narrow distance from the platform. As biochemical composition of OM reflects food availability for benthic organisms, our results suggest that the enrichment of macrozoobenthic communities around these structures could be the consequence of increased nutritional quality of resources.     

Responses of the whipscorpion, Mastigoproctus liochirus (Arachnida, Uropygi) to environmental humidity

Experiments were conducted to determine the responses of third-instar nymphs of the whipscorpion Mastigoproctus liochirus to various moisture (relative humidity) levels under constant temperature conditions, using a linear humidity gradient apparatus. No previous data exist on the water relations of this uropygid. Under saturated conditions (100% RH) animals showed no preference for any section of the chamber. When a humidity gradient was established (20 to 100% RH), whipscorpions exhibited a marked preference for an area of the chamber characterized by 70 to 80% RH.     

Flood resilience: consolidating knowledge between and within critical infrastructure sectors

Flood resilience has been rising up the political, economic and social agendas. Taking an integrated systems approach, using the right design guidance and tools and ensuring that education is in place for all stakeholders are three themes which are intrinsically linked to delivering flood resilience. This paper reviews these themes across the academic research, policy landscape and practitioner approaches, drawing conclusions on the way forward to increase our societies resilience to floods. The term ‘flood resilience’ is being increasingly used, however, it remains to be clearly defined and implemented. The UK, USA and Australia are leading the way in considering what flood resilience really means, but our review has found few examples of action underpinned by an understanding of systems and complexity. This review investigates how performance objectives & indicators are currently interpreted in guidance documents. It provides an in-depth exploration of the methods, that although developed through European and US expertise, can be used for worldwide application. Our analysis highlights that resilience is often embedded in engineering education and frequently linked to risk. This may however, mask the importance of resilience and where it differs from risk. With £2.6 billion to be spent in the UK over the next 6 years on strengthening the country’s flood and coastal defences, this is the opportunity to rethink resilience from a systems approach, and embed that learning into education and professional development of engineers. Our conclusions indicate how consolidating flood resilience knowledge between and within critical infrastructure sectors is the way forward to deliver flood resilience engineering.     

Early-life nutritional environment and spatial navigation in the water shrew, Sorex palustris (Insectivora)

Studies were conducted to study the effects of early-life nutritional environment on spatial navigation ability in the water shrew (Sorex palustris), as well as to provide information on life history traits and husbandry. The mean longevity of males and females in captivity was 652.3 +/- 33.8 SD and 616.2 +/- 22.5 days, respectively. Litter sizes ranged from 5 to 8 and neonatal mass ranged from 0.71 to 0.83 g. Spatial navigation was examined by use of the Morris water apparatus, where animals were required to locate the position of an escape platform in a circular tank of water. The platform was visible (proximal cue version of the task) in some tests. In other tests it was hidden beneath the surface (distal cue version) by making the water opaque using a non-toxic white dye. The tank was divided into 4 quadrants and the position of the plafform in any quadrant could be fixed for any subject or varied between subjects. Early-life under-nutrition was achieved by maintaining some shrews on a restricted diet (received half the amount of food as did controls). Under-nutrition was found to have an adverse effect on spatial navigation. Regardless of nutritional status, shrews were able to locate a hidden plafform that was placed at the center of a given quadrant more rapidly (escape latency) when it was visible (44 to 69 sec) than when it was hidden (83 to 164 sec). Results also showed that these shrews utilize both proximal and distal cues in this spatial task. Control subjects spent more time at a location where the platform had been in a previous test (69% of the trial period) than their undernourished counterparts (45 to 51%). This is the first experimental analysis of spatial navigation and the effects of early-life under-nutrition on this task, for S. palustris.     

These studies were conducted to assess the effects of lead toxicity on exploratory behavior and running. Effects of lead on exploratory behavior and running speed in the shrew, Blarina brevicauda (Insectivora)

These studies were conducted to assess the effects of lead toxicity on exploratory behavior and running speed in the short-tailed shrew, Blarina brevicauda. Shrews from the experimental group received 25 mg/kg/day of lead acetate in their drinking water for a period of 90 days. Control subjects received sodium acetate. Exploratory behavior was determined using a computerized activity chamber where movements of test subjects broke infrared beams projected onto the floor of the apparatus. Time spent (sec) in exploration was recorded over eight 6-min intervals. Running speed (km/hr) was measured in a microprocessor-controlled rectangular racetrack fitted with photocell timers. With respect to time spent in exploration, there were significant differences between lead-exposed (20.5-23.9 sec per 6-min testing session) and control subjects (6.8-8.1 sec) after the sixth testing interval in the activity chamber. With respect to maximal running speed, control subjects ran significantly faster (mean: 14.8 km/hr) than their lead-exposed counterparts (5.83 km/hr). Lead-exposed animals exhibited hyperactivity and increased random locomotor movements. They would frequently bump into the walls and their movements were more random. Controls typically ran along the racetrack in a straight line. These results represent the first data for the effects of lead exposure on exploratory behavior and running speed for shrews.     

Effect of lead exposure on spatial learning and running speed in the short-tailed opossum, Monodelphis domestica (Didelphidae)

Studies were conducted to assess the spatial learning ability in adult males of the short-tailed opossum, Monodelphis domestica using a T-maze, complex maze and elevated radial 8-arm maze. This is the first study of maze learning in opossums. In the T-maze, the performance of these animals improved over an 8-day training period. Eighty percent of the subjects initially trained to turn to the right for food reinforcement reached criterion (80% correct responses) by day 3 and all reached criterion by day 4. Reversal training (subjects then trained to turn to the left) was more difficult and required 8 days for all subjects to reach criterion. In the complex maze, 89% of the animals achieved the criterion level of performance (3 consecutive trials with 5 or fewer errors) on the eighth day of training and all reached criterion by day 10. The relative importance of intramaze vs. extramaze cues in directing choice behavior was investigated in the radial arm maze. A discrimination procedure was used which selectively rewarded subjects for following only one set of cues. Animals in the intramaze group obtained a food pellet from a cup at the end of each arm. In the extramaze group, the food cups were placed on a small platform just beyond the end of each arm. All subjects were initially trained to visit each arm with the maze in a fixed position (controls) and did so within 15 test sessions. Following these initial trials, the maze was rotated to a different position after each choice. For subjects in the intramaze group, the food moved in conjunction with the rotation of the arms thereby increasing the relevance of intramaze cues. In the extramaze group, extramaze cues became more important because the food remained on the platforms in the same position in the room. Animals in the extramaze group performed significantly better than chance whereas the intramaze subjects did not. This indicates that intramaze cues are not as important as extramaze cues for accurate choice behavior in this marsupial. In addition, animals injected with tetraethyllead showed a significant impairment in running speed and T-maze learning ability as compared to saline-injected controls.     

Environmental chemical cues associated with prey and subsequent prey preference in the wolf spider Hogna carolinensis Hentz (Araneae,Lycosidae)

The purpose of this study was to determine if environmental chemical cues associated with prey can affect subsequent prey choice in wolf spiderlings (Hogna carolinensis). After emergence from the egg sac, three groups of 10 spiderlings were each fed for one-week on one of three naturally-occurring prey species: group 1 fed on nymphs of the field cricket Gryllus pennsylvanicus; group 2 (house cricket, Acheta domesticus); group 3 (mole cricket, Gryllotalpa hexadactyla). They were then tested for subsequent prey preference in choice tests conducted in a plastic arena. Each spiderlings was presented simultaneously with one individual of each prey species in a randomized design. Spiderlings exhibited a significant first preference for the original diet. Thus, experience with certain foods (environmental chemical cues) encountered by newly hatched spiderlings can affect subsequent prey preference in this species.     

Effects of azadirachtin on mortality, fertilization, and swimming speed in larvae of the cane toad, Bufo marinus (Anura: Bufonidae)

Experiments were conducted to assess the effects of azadirachtin (AZ) on survival capacity, fertilization success, and swimming speed in larval stages of the cane toad, Bufo marinus . LC50 values (96-hr) for various larval stages exposed to 0.50 mg/l AZ were as follows: 5.35 (stage 12), 5.77 (stage 16), 787 (stage 20), 13.43 (stage 24), and 21.54 (stage 30). Tadpoles did not exhibit any apparent disorientation or production of mucous in response to AZ concentrations ranging from 0.3 to 0.5 mg/l. Mortality was significantly higher at 0.50 mg/l AZ than at lower concentrations. At 0.50 mg/l, mortality rate decreased significantly from 36% for stage 12 tadpoles, to 24% for stage 20 tadpoles. Mortality for early stages (stage 12) dropped significantly, from 36% at 0.50 mg/l, to 21% at 0.40 mg/l AZ There were no significant differences in percent mortality for any developmental stage at an AZ concentration of 0.3 mg/l, or for controls (no AZ). Exposure of gametes to 0.30 mg/l AZ did not reduce fertilization success as compared to controls (89.8 vs. 83.7%). At 0.40 mg/l, percent fertilization decreased significantly (68.8%). This effect was even more pronounced at 0.50 mg/l. No significant difference was found in swimming speeds between controls and subjects exposed to 0.30 mg/l AZ. However, at a concentration of 0.40 mg/l, tadpoles required a significantly longer period of time to swim a distance of 140 cm as compared to controls. The potential impact of AZ on amphibian populations is discussed.     

Chemosensory recognition of the marbled whiptail lizard, Aspidoscelis marmorata (Squamata: Teiidae) to odors of sympatric lizards (Crotophytus collaris, Coleonyx brevis, Eumeces obsoletus and Uta stansburiana) that represent different predation risks

The ability of the whiptail lizard Aspidoscelis marmorata (Teiidae) to detect and discriminate chemical stimuli associated with the integument of a sympatric saurophagous lizard (Crotaphytus collaris) was tested. Females of A. marmorata were presented with cotton swabs containing chemical cues from C. collaris and three species of nonsaurophagous lizards, as well as water and cologne (pungency control), and total number of tongue-flick (TF) recorded. Other responses were assessed including directed TF rate, time from initial presentation of the stimulus to first TF (latency), time spent fleeing from the stimulus, and number of flight bouts. The number of TFs, directed TF rate, and number of attempts at fleeing exhibited by were significantly greater when females were presented with swabs containing cues from C. collaris as compared to nonsaurophagous lizards and both control treatments. A. marmorata required significantly less time to elicit their first TF when presented with cues from C. collaris as compared to all other treatments. Most previous studies have focused on the responses of lizards to cues associated with snake predators. This study provides the first available data on responses of a teiid to cues associated with a saurophagous lizard.