Toxicity,uptake, and accumulation of nano and bulk cerium oxide particles in <Emphasis Type="Italic">Artemia salina</Emphasis>

Although the toxicological impact of metal oxide nanoparticles has been studied for the last few decades on aquatic organisms, the exact mechanism of action is still unclear. The fate, behavior, and biological activity of nanoparticles are dependent on physicochemical factors like size, shape, surface area, and stability in the medium. This study deals with the effect of nano and bulk CeO₂ particles on marine microcrustacean, Artemia salina. The primary size was found to be 15 ± 3.5 and 582 ± 50 nm for nano and bulk CeO₂ (TEM), respectively. The colloidal stability and sedimentation assays showed rapid aggregation of bulk particles in seawater. Both the sizes of CeO₂ particles inhibited the hatching rate of brine shrimp cyst. Nano CeO₂ was found to be more toxic to A. salina (48 h LC₅₀ 38.0 mg/L) when compared to bulk CeO₂ (48 h LC₅₀ 92.2 mg/L). Nano CeO₂-treated A. salina showed higher oxidative stress (ROS) than those treated with the bulk form. The reduction in the antioxidant activity indicated an increase in oxidative stress in the cells. Higher acetylcholinesterase activity (AChE) was observed upon exposure to nano and bulk CeO₂ particles. The uptake and accumulation of CeO₂ particles were increased with respect to the concentration and particle size. Thus, the above results revealed that nano CeO₂ was more lethal to A. salina as compared to bulk particles.     

Diversity and community structure of butterfly of Arignar Anna Zoological Park, Chennai, Tamil Nadu

Investigation was carried out on the diversity of butterfly fauna in selected localities of conservation and breeding center of Arignar Anna Zoological Park (AAZP), Chennai, Tamil Nadu. Atotal of 56 species were recorded, 15 of them belonged to Pieridae, 12 Nymphalidae, 9 Satyridae, 8 Papilionidae, 7 Danaidae, 3 Lycaenidae and 1 species each belonged to the families Acraeidae and Hesperidae. Qualitatively and quantitatively Pieridae family were comparatively dominant than that of other families. The notable addition to the 25 more species listed during this observation were compared to previous field survey. Comparison of butterfly species distribution between the different localities revealed that butterfly species richness was higher at mountain region with 52 species and lowest of 25 species at public visiting areas. Visitor's activities may be that reason for effects on butterfly distribution and lack of vegetation. Each five endemic and protected species (i.e. endangered) listed under the Wildlife (Protection)Act were highlighted greater conservation importances of the AAZP. It is suggest that butterfly species diversity generally increase with increase in vegetation and declines with the increase in disturbance.     

A bottom-up approach towards the assessment of ecological footprints and biocapacity

The concept of ecological footprint (EF) assessment embeds into the broader concept of sustainable development, relating directly to quality of life and maintaining the natural constraints of the global ecosystem. EFs relate to the balance between the Earth's biocapacity and consumption, measured as land equivalence in global hectares per capita. The majority of studies relating to EF assessments have adopted a top-down methodology in order to assess national and regional EFs. Furthermore, these studies are mainly based upon national accounts of input, output and trade; information which is readily available for most countries, and the EFs usually require an assessment of equivalent land area per capita to maintain the current levels of consumption. Since its inception in the mid-1990s, the EF methodology has been refined and has been widely adopted by many countries and governments as a tool to measure biocapacity, or, the consumption of resources. In this paper, we present a bottom-up methodology to measure the EF of a rural region (near Chennai) in southern India. Advantages and limitations of this approach are then discussed through comparisons with regional and national assessments.