Bacterial community analysis of Tatsoi cultivated by hydroponics

Tatsoi (Brassica narinosa) is a popular Asian salad green that is mostly consumed as a source of fresh produce. The purpose of this study was to assess the microbial diversity of Tatsoi cultivated in a hydroponic system and of its ecosystem. Tatsoi leaves, nutrient solution, and perlite/earth samples from a trickle feed system (TFS) and an ebb-and-flow system (EFS) were collected and their microbial communities were analyzed by pyrosequencing analysis. The results showed that most bacteria in the leaves from the TFS contained genus Sporosarcina (99.6%), while Rhizobium (60.4%) was dominant in the leaves from the EFS. Genus Paucibacter (18.21%) and Pelomonas (12.37%) were the most abundant microbiota in the nutrient solution samples of the TFS. In the EFS, the nutrient solution samples contained mostly genus Rhodococcus and Acinetobacter. Potential microbial transfer between the leaves and the ecosystem was observed in the EFS, while samples in the TFS were found to share only one species between the leaves, nutrient solution, and earth. Together, these results show that the bacterial populations in Tatsoi and in its ecosystem are highly diverse based on the cultivation system.     

Monitoring for Lead Pollution using Feathers of Feral Pigeons (Columba livia) from Korea

We investigated lead exposure conditions using unwashed feathers of feral pigeons as a monitor for lead pollution from rural, central urban, and four industrial complex areas in Korea with different ambient lead concentrations. Overall, the lead levels in the feathers increased when the atmospheric lead levels increased, so that the lead levels in the feathers from urban and industrial areas were two to four times greater than those in the rural area. However, there are no significant differences in the liver lead concentrations between rural and the other areas, suggesting that the lead originated from ingestion are not differences in locations. A positive correlation was found between the concentration of lead in livers and feathers from rural, indicating that the feather lead concentrations in this area seem to mainly reflect the internal tissue lead through the metabolic process. However, there are no significant correlations in the other areas, and we observed a relatively higher lead accumulation ratio of feathers to livers. It, therefore, indicates that external contamination onto the feather surface may be an important source for lead levels in feathers rather than transfer from internal tissue lead.     

Factors Causing Variations of Lead and Cadmium Accumulation of Feral Pigeons (Columba livia)

In order to understand the factors causing variation of lead and cadmium accumulation in tissues of feral pigeons in Seoul and Ansan, Korea, we investigated their age, food items (crop and gizzard contents) as well as environmental factors such as soil, atmosphere, and local traffic density. The results indicate that concentrations of Pb and Cd were highly increased in the order of eggs < chicks < adults. In food analysis, supplementary foods (rice, small stones, domestic scraps, cements, hairs, Styrofoam, etc.) could be considered as factors considering the Pb concentration differences. Concentrations of Cd in foodstuffs, the proportion of crop contents as their major foods could have an influence on the difference of Cd levels from a nutritional viewpoint. The Pb levels in gizzard contents and soil had an effect on the tissue accumulations, these were associated with the volume of vehicular traffic. However, we could not find any differences of Cd concentrations in gizzard contents and soil, although there were significantly different Cd accumulations in target organs of adult pigeons between the study areas. The Pb and Cd levels in tissues did not correspond to atmospheric metal levels.     

Assessing environmental factors in red spruce (Picea rubens Sarg.) growth in the Great Smoky Mountains National Park, USA: From conceptual model, envirogram, to simulation model

This study provides a method for assessing a multiplicity of environmental factors in red spruce growth in the Great Smoky Mountains National Park (GSMNP) of Southeastern USA. Direct and indirect factors in the annual growth increment are first organized into a schematic input-output envirogram (ARIRS), and this information is then used to construct a simulation model (ARIM). The envirogram represents a structured conceptualization of most environmental factors involved in growth, as developed from relevant literature. This interdisciplinary synthesis distinguishes direct vs. indirect factors in growth and takes account of the systems ecology concept that indirect factors may be as important as or more important than direct ones in regulating growth. The ARIRS envirogram summarizes hierarchically organized, within- and cross-scale, local-to-global interactions, and its construction makes it obvious that growth is influenced by many cross-scale spatiotemporal interactions. More research on genecology is still needed to clarify the role of phenotypic plasticity and adaptive capacity in nutrient cycling, global change, and human disturbance.