Precipitation Extremes and Flood Frequency in a Changing Climate in Southeastern Virginia

Despite the advances in climate change modeling, extreme events pose a challenge to develop approaches that are relevant for urban stormwater infrastructure designs and best management practices. The study first investigates the statistical methods applied to the land‐based daily precipitation series acquired from the Global Historical Climatology Network‐Daily (GHCN‐D). Additional analysis was carried out on the simulated Multivariate Adaptive Constructed Analogs (MACA)‐based downscaled daily extreme precipitation of 15 General Circulation Models and Weather Research and Forecasting‐based hourly extreme precipitation of North American Regional Reanalysis to discern the return period of 24‐hr and 48‐hr events. We infer that the GHCN‐D and MACA‐based precipitation reveals increasing trends in annual and seasonal extreme daily precipitation. Both BCC‐CSM1‐1‐m and GFDL‐ESM2M models revealed that the magnitude and frequency of extreme precipitation events are projected to increase between 2016 and 2099. We conclude that the future scenarios show an increase in magnitudes of extreme precipitation up to three times across southeastern Virginia resulting in increased discharge rates at selected gauge locations. The depth‐duration‐frequency curve predicted an increase of 2–3 times in 24‐ and 48‐h precipitation intensity, higher peaks, and indicated an increase of up to 50% in flood magnitude in future scenarios.     

Comparison of in vitro characteristics of and experimental lesions produced by a clinical and an environmental isolate of Aspergillus flavus

In the present study, two strains of Aspergillus flavus (one from a human corneal ulcer and one from the environment) were found to be strikingly similar in vitro in terms of thermotolerance, inability to grow in an anaerobic environment and in secreting proteinases; however, one obvious difference was that the clinical isolate produced 120 ppb of aflatoxin B1 in glucose salt medium while the environmental isolate did not produce this toxic metabolite. Alterations in the activities of acid phosphatase (ACP), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and glutathione-S-transferase were observed in the liver, kidney and serum in an experimental rat model, irrespective of whether the animal had been challenged with the clinical isolate or the environmental isolate of A. flavus. In rats that had been challenged with the clinical isolate, a significant decrease in the activity of kidney ALP was noted, whereas in rats that had been challenged with the environmental isolate, the reverse was observed. While these differential alterations may have occurred due to differences in the toxin-producing ability of the two isolates, further investigation is warranted to clarify whether other phenotypic, or genotypic, differences are also involved.     

Isolation of a salt tolerant laccase secreting strain of Trichoderma sp. NFCCI-2745 and optimization of culture conditions and assessing its effectiveness in treating saline phenolic effluents

Most of the hazardous pollutants are phenolic in nature and persists in the environment. The ability of laccases to oxidize phenolic compounds and reduce molecular oxygen to water has led to intensive studies of these enzymes. Therefore the fungal strains with high laccase activity and substrate affinity that can tolerate harsh environmental conditions have a potential for biotechnological applications. Salt tolerant laccase secreting fungi can be utilized in treatment of saline and phenolic rich industrial effluents such as coir effluent and textile effluent that needed to be diluted several fold before microbial treatment. This is the first study describing the isolation and optimization of a salt tolerant strain of Trichoderma sp. potential for industrial applications. The fungus was identified based on morphological characteristics and was subsequently confirmed with molecular techniques and deposited at National Fungal Culture Collections of India （NFCCI） under the Accession No. Trichoderma viride NFCCI 2745. In contrast to other laccase secreting fungi, light conditions did not exert much influence on laccase production of this strain and salinity enhanced its laccase secretion. The fungus effectively removed the phenolic content of the textile effluent, coir-ret liquor and wood processing effluent within 96 hr of incubation. The tolerance of the fungus to high salinity and phenolic compounds makes this strain ideal for treating saline and phenolic rich industrial effluents.     

Dynamics and determinants of land change in India: integrating satellite data with village socioeconomics

We examine the dynamics and spatial determinants of land change in India by integrating decadal land cover maps (1985–1995–2005) from a wall-to-wall analysis of Landsat images with spatiotemporal socioeconomic database for ~630,000 villages in India. We reinforce our results through collective evidence from synthesis of 102 case studies that incorporate field knowledge of the causes of land change in India. We focus on cropland–fallow land conversions, and forest area changes (excludes non-forest tree categories including commercial plantations). We show that cropland to fallow conversions are prominently associated with lack of irrigation and capital, male agricultural labor shortage, and fragmentation of land holdings. We find gross forest loss is substantial and increased from ~23,810 km² (1985–1995) to ~25,770 km² (1995–2005). The gross forest gain also increased from ~6000 km² (1985–1995) to ~7440 km² (1995–2005). Overall, India experienced a net decline in forest by ~18,000 km² (gross loss–gross gain) consistently during both decades. We show that the major source of forest loss was cropland expansion in areas of low cropland productivity (due to soil degradation and lack of irrigation), followed by industrial development and mining/quarrying activities, and excessive economic dependence of villages on forest resources.