Survival of the intertidal pulmonate Onchidium tumidium during short term and long term anoxic stress

Onchidium tumidium showed a triphasic response to anoxia. Twelve hours of anoxic exposure had no effect on the glycogen content in O. tumidium. However, there were significant increases in the alanine, lactate and succinate contents in the anoxic individuals. These were accompanied by a significant decrease in the ATP content. These results suggest that O. tumidium survived the first 12 h of anoxic exposure without increasing the glycolytic flux to compensate for the lower efficiency of ATP production through anaerobic pathways. Indeed, the fructose-2,6-bisphosphate (F-2,6-P₂) content and the percentage of phosphofruc-tokinase (PFK) associated with the subcellular particles remain unchanged in O. tumidium exposed to 12 h of anoxia. Hence, a reduction in the metabolic rate of these individuals might have occurred during such a period of anoxia. In contrast, in between 12 and 24 h of anoxic exposure, the glycogen content O. tumidium decreased significantly, and levelled off thereafter. A significant increase in the percentage of PFK associated with the subcellular particles was observed in individuals exposed to 24 h of anoxia. In addition, the F-2,6-P₂ content of these anoxic individuals increased significantly. Taken together, these two mechanisms could activate PFK and lead to a greater glycolytic flux. Beyond 24 h of anoxic exposure, survival of O. tumidium must have required considerable suppression of metabolism as accumulation of end products and depletions of glycogen and ATP had reached constant levels.     

Geochemistry of inorganic arsenic and selenium in a tropical soil: effect of reaction time, pH, and competitive anions on arsenic and selenium adsorption

Factors that can affect As and Se adsorption by soils influence the bioavailability and mobility of these elements in the subsurface. This research attempted to compare the adsorption capacities of As(III), As(V), Se(IV), and Se(VI) on a tropical soil commonly found in Singapore in a single-species system. The effect of reaction time, pH, and competitive anions at different concentrations on the adsorption of both As and Se species were investigated. The As and Se adsorption isotherm were also obtained under different background electrolytes. The batch adsorption experiments showed that the sequence of the As and Se adsorption capacities in the soil was As(V) > Se(IV) > As(III) > Se(VI). The adsorption kinetics could be best described by the Elovich equation. The adsorption of As(V), Se(IV), and Se(VI) appeared to be influenced by the variable pH-dependent charges developed on the soil particle surfaces. Phosphate had more profound effect than SO4(2-) on As and Se adsorption in the soil. The competition between PO4(3-) and As or Se oxyanions on adsorption sites was presumably due to the formation of surface complexes and the surface accumulation or precipitation involving PO4(3-). The thermodynamic adsorption data for As(V) and Se(IV) adsorption followed the Langmuir equation, while the As(III) and Se(VI) adsorption data appeared to be best-represented by the Freundlich equation.     

Use of waste iron metal for removal of Cr(VI) from water

Cr(VI) removal from water was evaluated using waste iron particles in batch experimental mode. The reaction rates were inversely proportional to the initial Cr(VI) concentrations, and the reaction rates of Cr(VI) removal with the waste iron metal were faster than those with Peerless iron, a commercial zero-valent iron. The loss in iron reactivity due to the oxidation, from Fe(0) to Fe(II), ultimately to Fe(III), could be recovered by adding iron-reducing consortium (IRC) to the oxidized iron. Bacterial reduction of Cr(VI) also helped to decrease the aqueous concentration of Cr(VI), but the reduction of oxidized iron by IRC and the consequent reduction of Cr(VI) to Cr(III) by the reduced iron was more significant. Thus, reusing waste iron metal for Cr(VI) removal can reduce the cost of reactive media. Furthermore, the addition of IRC to the waste iron metal can accelerate the removal rate of Cr(VI), and can recover the reactivity of irons which were oxidized by Cr(VI).     

Management and control of pollution in Inner Johore Strait

Coastal waters in South Johore, Malaysia are polluted to various degrees. The major pollution sources are domestric wastes from human settlements, agro-based wastes from palm oil mills and rubber processing factories, industrial effluents from industrial estates and discharges from animal farms. These pollution problems have adversely affected resources such as fisheries, recreational potential as well as the general aesthetic quality of the coastal environment particularly the Inner Johore Strait. Hence proper management and control measures are urgently needed to protect and further enhance the water quality to ensure environmentally sustainable development. This study examines various management options to control the pollution in the Inner Johore Strait. The options involve partial opening as well as complete removal of the Causeway to improve the tidal flow for more effective dilution and dispersion of pollutants. Computer simulation models are used to assess the impacts of the proposed options.     

The first discovery of a brachiosaurid from the Asian continent

Described here is a sauropod tooth from the Early Cretaceous of South Korea, similar to Brachiosaurus. The crown of the tooth is beveled off lingually so that when worn it presents a chisel-like edge. This find confirms the presence of a brachiosaurid in East Asia during the Early Cretaceous.     

Radium-226 levels and concentration ratios between water, vegetation, and tissues of ruffed grouse (Bonasa umbellus) from a watershed with uranium tailings near Elliot Lake, Canada

Radionuclide levels measured in bone, muscle, kidney and liver tissues, gut contents and diet items of 47 grouse from the Serpent River drainage basin, containing uranium (U) tailings at Elliot Lake, and from control areas in Ontario, showed variation by site and tissue. The mean level of 226radium (Ra) in bones of grouse sampled from Elliot Lake (28.5 mBq g(-1)) was higher than that in bones of birds from a distant control site near Sudbury, Ontario (8.0 mBq g(-1)) but similar to the value in a local control population (28.1 mBq g(-1)). Birds from Mid- and Low-Serpent River basin populations (with 17.1 and 17.7 mBw g(-1), respectively) did not differ from local or distant control populations; muscle, liver and kidney had lower 226Ra concentrations, which did not differ significantly among populations. Levels of 226Ra in the crop contents and intestine did not differ significantly by site and were similar to those of food items consumed by the birds. Stomach content values were higher in birds sampled in Elliot Lake and at the local control site than in those taken at the distant control site; birds sampled downstream from Elliot Lake did not differ from distant controls in this regard. Levels of 232thorium (Th) and 230Th were below detection limits (0.1 microg g(-1) and 5.0 mBq g(-1), respectively) in bone, muscle and liver tissue in two grouse with elevated levels of 226Ra. Other radionuclides were measurable in some tissues: 238U in bone at 0.4 microg g(-1), in muscle to 0.2 microg g(-1), in liver to 1.0 gmg g(-1.), 228Th was found only in muscle (8.0 mBq g(-1)), 210poloniuim (Po) was found in bone, muscle and liver (maxima: 24.0, 7.0, 16.0 mBq g(-1)) with the exception of one muscle sample; 210lead (Pb) was detected in only one liver sample (50.0 mBq g(-1)). Environmental levels fell within ranges previously reported at the sites, or at similar locations elsewhere. Leaves of trembling and largetooth aspen growing in the basin had mean 226Ra levels of 14.8 and 52.7 mBq g(-1) (dry weight) respectively, and fungal material carried up to 215.4 mBq g(-1) (air-dried), with some variation by site. River and lake waters sampled near the U tailings had 118.1 mBq litre(-1) of dissolved 226Ra; at the distant control site the value was 12.1 mBq litre(-1). The concentration ratios (CR) between bone of grouse collected at the Elliot Lake sites and trembling and largetooth aspen leaves were 1.38 and 1.09 (fresh weight basis); from other diet items and to other tissues the values were less than unity. Bone tissue: water ratios, based on dissolved 226Ra levels, ranged to 30.89. People eating grouse from the study area are unlikely to consume radionuclides in excess of limits currently established by Canadian regulatory authorities.     

226Ra and other radionuclides in water, vegetation, and tissues of beavers (Castor canadensis) from a watershed containing U tailings near Elliot Lake, Canada

Radionuclide levels were measured in tissues, gut contents, diet items, and water at site of capture, of adult beavers from the Serpent River drainage basin which contains U tailings at Elliot Lake, Ontario, and from nearby control sites. Levels of (226)Ra in beaver bone, muscle and kidney were highest in animals from locations close to U tailings; liver levels did not vary by site. Environmental (226)Ra levels were within ranges previously reported at these or similar locations elsewhere; levels in beaver gut contents reflected levels in diet items. Concentration ratios exceeded unity only between some vegetation items and beaver bone at the Elliot Lake site and were less than 0.19 between vegetation and other tissues. In two beavers with tissue levels of (226)Ra higher than other sampled, neither (232)Th nor (230)Th were detected in bone, muscle or liver tissues. U-238 was measurable in bone, muscle and liver, (228)Th in bone, (210)Po bone, muscle and liver; and (210)Pb was measurable only in bone. Estimated yearly intakes of radionuclides by people eating beavers were calculated to be below current allowable levels set by the Canadian regulatory authorities.     

An agenda for research and action toward diverse and just futures for life on Earth

Decades of research and policy interventions on biodiversity have insufficiently addressed the dual issues of biodiversity degradation and social justice. New approaches are therefore needed. We devised a research and action agenda that calls for a collective task of revisiting biodiversity toward the goal of sustaining diverse and just futures for life on Earth. Revisiting biodiversity involves critically reflecting on past and present research, policy, and practice concerning biodiversity to inspire creative thinking about the future. The agenda was developed through a 2-year dialogue process that involved close to 300 experts from diverse disciplines and locations. This process was informed by social science insights that show biodiversity research and action is underpinned by choices about how problems are conceptualized. Recognizing knowledge, action, and ethics as inseparable, we synthesized a set of principles that help navigate the task of revisiting biodiversity. The agenda articulates 4 thematic areas for future research. First, researchers need to revisit biodiversity narratives by challenging conceptualizations that exclude diversity and entrench the separation of humans, cultures, economies, and societies from nature. Second, researchers should focus on the relationships between the Anthropocene, biodiversity, and culture by considering humanity and biodiversity as tied together in specific contexts. Third, researchers should focus on nature and economies by better accounting for the interacting structures of economic and financial systems as core drivers of biodiversity loss. Finally, researchers should enable transformative biodiversity research and action by reconfiguring relationships between human and nonhuman communities in and through science, policy, and practice. Revisiting biodiversity necessitates a renewed focus on dialogue among biodiversity communities and beyond that critically reflects on the past to channel research and action toward fostering just and diverse futures for human and nonhuman life on Earth.     

A decomposition analysis of CO2 emissions: evidence from Malaysia’s tourism industry

The most important question raised from issues of environmental degradation is how economic activities bring about changes that will result in pollution. In the pursuit of tourism economy, contrary to popular interest, the travel and tourism (T&T) industry may cause environmental damages through the emissions of carbon dioxide (CO₂) from energy consumption in areas such as transportation and delivery of amenities. Given this major concern, this paper attempts to investigate the linkage between tourism and CO₂ emissions in Malaysia between 1981 and 2011. In particular, this study fills the knowledge gap by taking a closer look at the impact of international tourist arrivals on CO₂ emissions by sector – electricity and heat generation and transport. Results from the bound test method suggest that there exists a long-run relationship among the variables under consideration when CO₂ emissions become the dependent variable. The original result is similarly robust to alternatives, which are CO₂ emissions from sectors of electricity and heat generation and transport. Furthermore, the vector error correction model causality analysis indicates a causal relationship between tourism and CO₂ emissions by transport and electricity and heat generation. Subsequently, several tourism-related policies are drawn from these findings.     

Reactive Blending of Biodegradable Polymers: PLA and Starch

Poly(lactic acid) (PLA) and starch are important biodegradable polymers. Mechanical properties of blends of PLA and starch using conventional processes were very poor because of incompatibility. In this study, PLA and starch were blended with a reactive agent during the extrusion process. The affects of the reactive blending were investigated and significant improvements were confirmed by measuring the tensile strength and elongation at break, IR spectra, and DSC.