云南禄丰煤岩与围岩中富勒烯（C60）物质的初步探索

中国云南煤中是否存在富勒烯还没有科学定论。本工作运用高效液相色谱方法，对中国云南禄丰晚三叠世煤岩及其围岩中是否存在天然富勒烯物质的问题进行了探索性研究；同时发展了适于从复杂地质样品中分离纯化富勒烯和定性与定量检测富勒烯的一套技术方法。结果显示，从定性角度有两个样品确实存在富勒烯。本文据此提出，富勒烯的赋存与煤岩／围岩交互相上的含煤碳质泥岩有着密切的关系。下一步研究应着重调查比煤岩与顶板和底板界面层并大力研究其中天然富勒烯的地学成因。本工作的意义还在于为今后我国加入和独立开展以富勒烯类物质（如C60／C70）及其衍生物质（如He C60 C70)作为地球化学示踪物的古地球突变大事件的研究，奠定了实验方法学基础。     

Variation in tree mortality and regeneration affect forest carbon recovery following fuel treatments and wildfire in the Lake Tahoe Basin, California, USA

Background

Forest fuel treatments have been proposed as tools to stabilize carbon stocks in fire-prone forests in the Western U.S.A. Although fuel treatments such as thinning and burning are known to immediately reduce forest carbon stocks, there are suggestions that these losses may be paid back over the long-term if treatments sufficiently reduce future wildfire severity, or prevent deforestation. Although fire severity and post-fire tree regeneration have been indicated as important influences on long-term carbon dynamics, it remains unclear how natural variability in these processes might affect the ability of fuel treatments to protect forest carbon resources. We surveyed a wildfire where fuel treatments were put in place before fire and estimated the short-term impact of treatment and wildfire on aboveground carbon stocks at our study site. We then used a common vegetation growth simulator in conjunction with sensitivity analysis techniques to assess how predicted timescales of carbon recovery after fire are sensitive to variation in rates of fire-related tree mortality, and post-fire tree regeneration.

Results

We found that fuel reduction treatments were successful at ameliorating fire severity at our study site by removing an estimated 36% of aboveground biomass. Treated and untreated stands stored similar amounts of carbon three years after wildfire, but differences in fire severity were such that untreated stands maintained only 7% of aboveground carbon as live trees, versus 51% in treated stands. Over the long-term, our simulations suggest that treated stands in our study area will recover baseline carbon storage 10?C35?years more quickly than untreated stands. Our sensitivity analysis found that rates of fire-related tree mortality strongly influence estimates of post-fire carbon recovery. Rates of regeneration were less influential on recovery timing, except when fire severity was high.

Conclusions

Our ability to predict the response of forest carbon resources to anthropogenic and natural disturbances requires models that incorporate uncertainty in processes important to long-term forest carbon dynamics. To the extent that fuel treatments are able to ameliorate tree mortality rates or prevent deforestation resulting from wildfire, our results suggest that treatments may be a viable strategy to stabilize existing forest carbon stocks.     

Boulder shores in South Africa – a distinct but poorly documented coastal habitat type

This study compares the composition, species richness and biomass of macrofaunal and algal assemblages on intertidal boulder shores as compared with those on adjacent rock-platforms, at six sites along the southwest coast of South Africa. Of 214 species identified, 175 were recorded on boulder shores and 124 on rock-platform shores; of these, 99 species were common to both habitat types, 92 were exclusive to boulders, and 23 were exclusive to rock-platforms. Significant differences in community structure (F_(1,95) = 13.02, p < 0.01) (PERMANOVA test), species richness (F_(1,95) = 14.28, p < 0.01), biomass (F_(1,95) = 9.45, p < 0.01) and diversity (F_(1,95) = 578.83, p < 0.01) (two-way ANOVA) were detected between the two habitat types. Average dissimilarity of community structure between rock-platform and boulder shores was 87.96% (SIMPER analysis). The increased species richness and biomass on boulder shores extended across all tidal levels, but was most marked in the highshore. These results confirm that boulder shores along the southwestern Cape support a distinct biota, richer and very different from that on adjacent rock-platforms, and rich in boulder-dependent species. We propose that boulder shores merit separate management and conservation targets as compared to rock-platforms, though the ecology of boulder shores in the region remains very poorly known and requires further study.     

Focusing on monofilament nets while overlooking the priorities of artisanal fisheries governance in Senegal

Despite its legal prohibition since 1998, the nylon monofilament net is still widely used in Senegalese artisanal fisheries. To achieve a complete ban on monofilament use, it is necessary to understand the main arguments for its continued use and what alternatives exist. Using a field experiment among local fishers as well as empirical knowledge and a literature review, this article highlights the challenges to the eradication of nylon monofilament. Our study shows that in a context where decision-makers pay too much attention to social, economic and political stakes, the efficiency of nylon monofilament nets confers a major advantage upon which fishers rely, and this counters any regulatory action against this type of gear. Moreover, numerous studies globally have indicated that communication campaigns that focus on the ghost-fishing power of this type of net seem to be inappropriate. We concluded that the issue of continued use of monofilament should be addressed through an integrated fisheries management programme that reduces overcapacity and fosters sustainable fishing practices.