Scope for growth of Mytilus?galloprovincialis (Lmk., 1819) in oligotrophic coastal waters (Southern Tyrrhenian Sea, Italy)

The ‘scope for growth’ (SFG) tool was used to study the growth performance of cultivated populations of Mytilus galloprovincialis (Lmk., 1819) in an oligotrophic area of the Southern Mediterranean Sea. The study was carried out between 1993 and 1996 by using data from four seasonal oceanographic cruises and from growth experiments. Water samples were collected and analysed for total suspended matter (TSM), particulate organic carbon (POC) and nitrogen (PON), particulate lipids, proteins and carbohydrates and chloropigments. The sum of the carbon equivalents of carbohydrates, proteins and lipids is indicated as the total biopolymeric particulate organic carbon (BPC) and was converted into a unit of energy in order to calculate the SFG of a theoretical mussel of 5 cm length. In order to test the performance of mussel growth at two depths (5 and 15 m water depth), mussel body size [as ash free dry weight (AFDW)] and the actual concentrations of BPC were used to calculate the monthly SFG using the physiological energetic relationships suggested in the current literature. Data from the field cruises led us to characterise the study site as ultra-oligotrophic (annual average of chloropigment concentration approximately 0.5 μg L⁻¹). SFG calculations allowed us to identify a site where mussels grown successively were found to reach a commercial size in approximately 12 months. The good agreement obtained between energetic response and subsequent production response suggests that the available energy from particulate food could be fully available for organic production for maintaining “proportionate” growth trajectories, even in a ultra-oligotrophic system.     

Temperature adaptation of the heart in the grass snake (Natrix natrix L.), common European viper (Vipera berus L.), and steppe viper (Vipera renardi Christoph) (Reptilia: Squamata: Serpentes)

Changes in the heart rate (HR) in more and less thermophilic reptiles (Natrix natrix L., Vipera berus L., and V. renardi Christoph) exposed to heating from 0 to 40°C under anesthesia have been found to depend on the previous adaptation of the animals to the temperature parameters characteristic of the natural habitats of their populations.     

Depth-related shift in life history strategies of a brooding and broadcasting deep-sea asteroid

Combining field and laboratory work, this study investigated the reproductive cycle, aggregative behavior, spawning periodicity, development and early growth of the sea star Henricia lisa living at bathyal depths off eastern Canada. Marked differences were found between individuals from ~1,300 and ~600 m deep. The former had a male biased sex ratio and an aperiodic reproductive cycle, whereas the latter displayed an equal sex ratio and a biannual breeding pattern. Furthermore, the maximum size was larger and female fecundity roughly five times higher in shallower compared to deeper populations. In the tanks, aggregative behavior was recorded twice a year during the summer and winter breeding periods. The onset of aggregations and spawning coincided with a temperature of 3–4°C. Males spawned first and females typically responded inside 30–60 min. Between 12 and 20 eggs were retained to be brooded under the arched arms of the female, whereas the remainder were broadcasted and developed without parental care. The fertilized eggs underwent a first cleavage after 12 h, reached the brachiolaria stage in 1 month, became juveniles within 3–4 months and reached ~ 4 mm in diameter after 14–17 months of growth. The embryos and juveniles developed at the same rate whether brooded or not, and development of winter cohorts was typically slower due to lower prevailing temperatures. This study of H. lisa provides the first evidence of lecithotrophy in a seasonally breeding deep-sea echinoderm and of brooding in a deep-sea asteroid.     

The influence of arsenic speciation (AsIII & AsV) and concentration on the growth, uptake and translocation of arsenic in vegetable crops (silverbeet and amaranth): greenhouse study

We examined arsenic (As) uptake by vegetable crops (amaranth, Amaranthus gangeticus, and silverbeet, Beta vulgaris) as affected by As speciation (As^III and As^V) and their concentrations in nutrient solution. Amaranth and silverbeet were grown in a nutrient solution containing four levels of arsenate (As^V): 0, 1, 5, and 25 mg As/l and three levels of arsenite (As^III): 0, 5, 10 mg As/l. Both As^V and As^III are phytotoxic to these crops with the latter being five times more toxic. Amaranth treated with As^III exhibited As toxicity symptoms within 48 h of exposure and was close to death within 1 week. However, As^V treatment did not show clear toxicity symptoms other than wilting and yield reduction at the highest dose rate of 25 mg As^V/l. The main mechanism used by vegetable crops to tolerate As^V is probably avoidance—limiting As transport to shoots and increasing As accumulation in the root system. When As^V was added to the nutrient solution, the uptake of As in shoots increased and, at the highest dose (25 mg As^V/l), 60 μg As/g DW (3.6 mg/kg FW) accumulated in the edible portion, which exceeds the WHO recommended limit for food stuffs (2 mg/kg FW) as the water contents of the crops were 94%. It is therefore important to determine the nature of the As species and their bio-accessibility. Iron treatment with 0.5 mg NaFe(III)EDTA/l dose decreased silverbeet As uptake by 45% given its affinity to bind As at the root surface or root rhizosphere and so restrict As translocation to the shoots.     

Support for Hawaiian humpback whales

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Support for Hawaiian humpback whales     

Time series analysis of coal mine accident experience

This study investigates several forecasting techniques that can be useful to mine safety managers for studying mine accident rate behavior. Three time series models were studied for extrapolation of accident rates. These models are applied to historical accident incidence data from a coal mine. Further, a method is presented for evaluating the three models for the selection of an appropriate model. For this particular mine application, it is concluded that the more complex Box-Jenkins ARMA model as well as first order autoregressive model do not give better results than the simple exponential smoothing model. However, when the random variations or autocorrelations in the accident experience rates between periods are different, the models may predict differently. As such, specific models must be developed for each mine on the basis of statistical analysis of the mine accident experience data over time. Moreover, the importance of incorporating human judgement to interpret the results of statistical forecasting cannot be overemphasized. Integration of policy or operating changes, which may impact mine safety performance, with statistical forecasting techniques is essential to arrive at a realistic prediction of future performance.     

Fuelwood Use in the Cities of the Developing World: Two Case Studies from India

A number of studies of traditional fuel supply and demand in rural areas of developing countries have been undertaken, but little has been done to make comparable studies for urban populations. This paper reports on two studies undertaken on fuelwood supplies, their transporation and distribution and utilization in the Indian cities of Bangalore and Hyderabad.
Substantial amounts of fuelwood—200 000 tonnes in Hyderabad and 450 000 tonnes in Bangalore—are consumed. Seventy-eight percent of the fuelwood is consumed by households where it is a major source of energy for cooking and heating for low income families. While the researchers did not visit the forest areas which are the source of fuelwood, the quantity consumed is so large as to indicate that deforestation is possibly severe. Recommendations are made to deal with the problem.