Radiative absorption enhancements due to the mixing state of atmospheric black carbon

Atmospheric black carbon (BC) warms Earth's climate, and its reduction has been targeted for near-term climate change mitigation. Models that include forcing by BC assume internal mixing with non-BC aerosol components that enhance BC absorption, often by a factor of ~2; such model estimates have yet to be clearly validated through atmospheric observations. Here, direct in situ measurements of BC absorption enhancements (E(abs)) and mixing state are reported for two California regions. The observed E(abs) is small-6% on average at 532 nm-and increases weakly with photochemical aging. The E(abs) is less than predicted from observationally constrained theoretical calculations, suggesting that many climate models may overestimate warming by BC. These ambient observations stand in contrast to laboratory measurements that show substantial E(abs) for BC are possible.     

Flexible retinotopy: motion-dependent position coding in the visual cortex

Although the visual cortex is organized retinotopically, it is not clear whether the cortical representation of position necessarily reflects perceived position. Using functional magnetic resonance imaging (fMRI), we show that the retinotopic representation of a stationary object in the cortex was systematically shifted when visual motion was present in the scene. Whereas the object could appear shifted in the direction of the visual motion, the representation of the object in the visual cortex was always shifted in the opposite direction. The results show that the representation of position in the primary visual cortex, as revealed by fMRI, can be dissociated from perceived location.     

Estimating the frequency and extent of bloodworm digging in Maine from aerial photography

The extent and frequency of bloodworm digging in northeast North America has never been investigated, making bloodworm fishery management difficult and an assessment of ecological impact impossible. We examined the spatial and temporal patterns of bloodworm digging by surveying 13 mudflats in mid-coast Maine using monthly aerial photography. We used ArcGIS to “georeference” spatial information into the photographs, allowing us to quantify the area of the mudflat disturbed by digging. Of the 122 ha of flats we monitored, almost 48% was dug in 2006, and 24% was dug in 2007, corresponding to 57.9 ha and 24.8 ha, respectively. Individual flats in this study were dug as much as 155% and as little as 0% annually, but rarely were they dug more than once a year as studies assessing the impact of digging on soft-sediment communities have assumed. Digging activity peaked in early spring with a smaller peak in August. On average, 3% of the visual evidence of digging faded each month. Except for those erased by winter storms and ice scour, no dug strip faded before 5 months of age, therefore flats could be monitored every 4–5 months for an accurate estimate of digging activity. Our results allow us, for the first time, to estimate the impact of digging on the bloodworm resource and to design realistic experiments to measure the impact of digging on the soft-sediment community and non-target species.     

The effect of land use change and ecotourism on biodiversity: a case study of Manuel Antonio,Costa Rica,from 1985 to 2008

Development in biodiversity rich areas is of global concern. While development may lead to socioeconomic benefits, this often comes concomitant with biodiversity loss and deforestation. Biodiversity rich areas present the opportunity for both improvements in socioeconomic conditions and conservation; however numerous challenges exist. Costa Rica’s Manuel Antonio National Park presents an ideal case study to investigate the balance between alternative forms of development which have contrasting environmental impacts. The Manuel Antonio region is a highly dynamic landscape experiencing deforestation, from agriculture, cattle ranching and oil palm plantations; and also reforestation from abandonment of land holdings and nature oriented tourism. Landscape dynamics are closely intertwined with the livelihoods and perspectives on biodiversity conservation of local communities, determining ecological sustainability. We use an analysis combining multi-temporal remote sensing of land cover dynamics from 1985 to 2008 with questionnaire data from local families on their socioeconomic status, perspectives on conservation, and perceived changes in local wildlife populations. Our results show that, while regeneration occurred and forest fragmentation in the area decreased from 1985 to 2008, Manuel Antonio National Park is rapidly becoming isolated. Decreasing ecological connectivity is related to the rapid expansion of oil palm plantations adjacent to the park and throughout the lowland areas. Perceived decreases in wildlife abundance and compositional change are evident throughout the area, with local communities attributing this primarily to illegal hunting activities. Nature based tourism in the area presents an effective strategy for conservation, including reductions in hunting, through increased valuation of biodiversity and protected areas, and socioeconomic advantages. However, without urgent efforts to limit deforestation and preserve the remaining forested corridor connecting the park to core primary forest, the ability to maintain biodiversity in the park will be reduced.     

Metabolism, seedling growth and nucleolar activity in germinating diploid wheat Triticum monococcum ssp. monococcum cv. Einkorn

Seed germination, seedling growth, mitotic and nucleolar activity were investigated as indicators of metabolic activity in a diploid wheat, Triticum monococcum ssp. monococcum cv. Einkorn. Two developmental phases were identified, an initial lag phase during which reactivation of NOR's and the initiation of mitotic activity (10 h) took place prior to the appearance of the primary root (16 h). Dominance interactions were observed between the NOR's of chromosomes 1A and 5A with the NOR's of the one pair activated before the other and forming therefore larger nucleoli. The total number of nucleoli per 500 cells also varied according to the stages of the cell cycle over time. The mitotic activity had an initial exponential rise, but showed signs of flattening out after 10 h of mitosis with opposite levels of activity in the primary and first pair of lateral roots thereafter. Secondly, an exponential phase in root and shoot growth, mobilization of reserve food and respiration rate was observed during seedling growth. Comparisons were done on work from a previous investigation on two polyploid wheat accessions belonging toT. turgidum ssp. durum and T. aestivum species. T. monococcum displayed a higher embryo growth than the polyploids, that may be explained by having a lighter embryo and caryopsis weight that may influence the uptake of water and reactivation of metabolic activity. During the seedling growth period, the two polyploid species displayed a faster growth rate than the diploid probably due to the differences in the number of genomes, the hybrid nature of the polyploids and a more complex gene control in the polyploids. This revised version was published online in August 2006 with corrections to the Cover Date.     

Abbau von Anilin, 4-Chloranilin und 3,4-Dichloranilin in verschiedenen Böden

Degradation of aniline, 4-chloroaniline and 3,4-dichloroaniline in various soils The degradation of aniline, 4-chloroaniline and 3,4-dichloroaniline was investigated in laboratory experiments with 4 different soil types and a concentration of 1ppm. The experiment time was 10-16 weeks. Aniline was mineralized during 10 weeks from 16,2 to 26,3%, while the degradation rate was 12,3 to 17,2% with 4-chloroaniline. With 3,4-dichloroaniline degradation was reduced to 3,9 to 11,9%. At the end of the experiment 60% and more of the ¹⁴C-activity was bound to the soil complex and could not be extracted by different solvents. Because of the low degradation of chloroanilines and the strong sorption there should be an accumulation in the soil. Anilines are metabolites of different chemicals used in plant protection.