Tree population dynamics of three altitudinal vegetation communities on Mount Cameroon (1989�C2004)

Changes in permanent sample plots in the lowland,submontane and montane forests on Mount Cameroon(4,095 m above sea level),an active volcano,are described for 15 years from 1989 to 2004.Throughout the study period,the stocking level of trees with a diameter at breast height(DBH) ≥ 10 cm in the three forests were lower than in pan-tropical stands suggesting a significant impact of volcanic and human-related activities on the vegetation communities on the mountain.Annual mortality rates in the submontane and montane forests were consistent with those reported for comparable altitudinal ranges in the Blue Mountains of Jamaica.The annual mortality rate was higher in the lowland forest than other lowland sites included.Divergence between recruitment and mortality rates was large suggesting that the three vegetation communities have not reached their climax.The seven-year difference in half-life of large trees(with a DBH ≥ 50 cm) in the submontane and montane forests suggests an altitudinal effect on turnover of larger trees that in turn contributes to the frequent small stature of high altitude forests.There was little evidence of an altitudinal effect on species turnover and growth rate.This finding supports generalizations about the zero effect of growth on the stature of high altitude trees.Understanding forest dynamics is crucially important in the management of tropical montane environmentsand in this instance particularly so given the recent creation of the Mount Cameroon National Park.     

基于历史地震数据的地震烈度与人员死亡率相关性研究

基于历史震例数据,通过对不同烈度的人员死亡率的分析发现,人员死亡率与地震烈度存在着正相关关系,即人员死亡率随烈度的增加而增大,不同烈度的人员死亡率有各自的分布区间范围,而通过对相邻烈度的人员死亡率的分析发现,相邻烈度人员死亡率存在着1个数量级的倍数关系,一般在10倍左右,在低烈度区域,倍数关系集中于偏向大于10倍的区间范围;在高烈度区域,倍数关系集中于小于10倍的区间范围。在此结果上,基于地震烈度、震级等因素构建了烈度人员死亡率模型,决定系数R²值为0.8667,拟合结果相对较好,能够为后续基于分烈度人员死亡率的地震人员死亡评估模型提供参考。     

The larvae of congeneric gastropods showed differential responses to the combined effects of ocean acidification,temperature and salinity

The tolerance and physiological responses of the larvae of two congeneric gastropods, the intertidal Nassarius festivus and subtidal Nassarius conoidalis, to the combined effects of ocean acidification (pCO₂ at 380, 950, 1250 ppm), temperature (15, 30 °C) and salinity (10, 30 psu) were compared. Results of three-way ANOVA on cumulative mortality after 72-h exposure showed significant interactive effects in which mortality increased with pCO₂ and temperature, but reduced at higher salinity for both species, with higher mortality being obtained for N. conoidalis. Similarly, respiration rate of the larvae increased with temperature and pCO₂ level for both species, with a larger percentage increase for N. conoidalis. Larval swimming speed increased with temperature and salinity for both species whereas higher pCO₂ reduced swimming speed in N. conoidalis but not N. festivus. The present findings indicated that subtidal congeneric species are more sensitive than their intertidal counterparts to the combined effects of these stressors.     

大鳍鳠的生长、死亡及合理利用研究

用SAS统计软件拟合了大鳍的体长生长方程和体重生长方程：Lt＝79．5（1－e－0.0533(t+2.0982)）,W＝3370（1-e－0.0533(t+2.0982)）2.7744,并估算了其自然死亡系数M、捕捞死亡系数F。应用Beverton－Holt模式,研究了嘉陵江水系大鳍的资源状况,为开发利用提供科学依据。     

Mortality in England during the 1783–4 Laki Craters eruption

1783/4 has been recognised as a mortality crisis year in the population history of England. This demographic incident coincides with the Laki Craters eruption, Iceland, which began in June 1783 and fumigated many parts of Europe with volcanic gases and particles. Many reports and proxy climate records implicate the volcanic cloud in meteorological anomalies, including notably hot 1783 summer conditions in England and a severe subsequent winter. We present here a detailed analysis of the geographical and temporal trends in English mortality data, and interpret them in the light of the climatological records and observations of the pollutant cloud. We show that there were two distinct crisis periods: in August-September 1783, and January-February 1784, which together accounted for ~20,000 extra deaths. In both cases, the East of England was the worst affected region. Possible causes for the two crisis periods are considered and we conclude that the timing and magnitude of the winter mortality peak can be explained by the severe cold of January 1784. The late summer mortality followed 1–2 months after the very hot July of 1783 and may also have been related to the weather, with the time lag reflecting the relatively slow spread of enteric disease or the contraction of malaria. However, it is hard to explain the entire late summer anomaly by these high temperature causes. We therefore consider that fine acid aerosol and/or gases in the volcanic haze may also have contributed to the unusual August-September mortality. Given that complex radiative and dynamical effects of the volcanic cloud are implicated in the climatic anomalies in 1783–4, it is likely that the Laki Craters eruption did play a role in the English mortality crises of the same period.Editorial responsibility: R. Cioni     

Mass Mortality in the Gulf of Trieste: The Course of Community Destruction

Abstract. Over a period of two weeks in September, 1983 a high biomass macroepifauna community characteristic of a greater part of the Gulf of Trieste suffered mass mortality. The affected area is estimated to cover several hundred km2. Within 2–3 days all sponges and the brittle star Ophiothrix quinquemaculata, which together make up over 60 % of the community biomass, were dead. Benthic fish, mostly gobiids, were already affected on the first day and littered the bottom in great numbers. Concurrently the complete spectrum of macroinfauna species including (in order of emergence) holothurians, burrowing shrimp, echinoids, polychaetes, sipunculids and bivalves appeared on the sediment surface. Within one week sea stars and all remaining ophiurids had died. At this time hermit crabs were found lying dead next to their shells. Several anemones survived into the last week, although many showed signs of severe stress and lay on the surface with exposed pedal discs. Oxygen deficiency is the apparent immediate cause of this phenomenon and several possible factors leading to anoxic conditions in the Gulf are discussed. This ecological catastrophy provides evidence that the affected community, considered to have achieved relative stability by developing a strategy effectively dampening the effect of physical oscillations, has a distinct tolerance limit to stress. The Gulf of Trieste, among the most productive areas in the Mediterranean Sea, must be considered as sensitive; September is a particularly critical month.     

Spatial spillover and the socio-ecological determinants of diabetes-related mortality across US counties

The spatial structure of diabetes-related mortality in US counties is evident from previous studies. However, it is not clear if spatial variation in diabetes-related mortality is associated with spatial variation in socioecological factors. We analyze the spatial spillover effect of changes in socioeconomic gradients (education, employment, household income), retail food environments, and access to health care, on diabetes-related mortality rates across the United States. Seven-year aggregates of multiple cause mortality data from the CDC WONDER compressed mortality database were merged with several sources of county-level data to examine mortality clusters, factors associated with the clusters, and spatial spillover effects in 3109 continuous US counties. The results suggest that high diabetes-related mortality cluster counties are located throughout the Southern Plains, Southeastern, and Appalachian regions. Lower socioeconomic status, a high density of fast food restaurants, a lack of access to grocery stores, a high proportion of Blacks, and low physical activity characterize high diabetes-related mortality rates clusters. The impacts from improvements in socioeconomic gradients and the retail food environment in neighboring counties spill over, and reduce the diabetes-related mortality rate in a particular county. This result implies that improvements in socioeconomic status and access to healthy food would significantly reduce diabetes-related mortality rates in contiguous US counties.     

Tree Population Dynamics of Three Altitudinal Vegetation Communities on Mount Cameroon(1989-2004)

Changes in permanent sample plots in the lowland,submontane and montane forests on Mount Cameroon(4,095 m above sea level),an active volcano,are described for 15 years from 1989 to 2004.Throughout the study period,the stocking level of trees with a diameter at breast height(DBH) ≥ 10 cm in the three forests were lower than in pan-tropical stands suggesting a significant impact of volcanic and human-related activities on the vegetation communities on the mountain.Annual mortality rates in the submontane and ...     

海水网箱养殖鱼类越冬期的死亡原因及对策

在冬春季低水温期,海水网箱养殖的鱼类大批死亡造成了严重的经济损失。本文对死亡的原因进行了初步研究,结果表明:在一定的低水温环境下,这些鱼类虽然因冻伤而造成局部坏死,但维持生命的主要器官的机能仍处于基本正常状态;而患鱼继发感染细菌致病才是其死亡的主要原因。采取适当的越冬防寒措施可提高养殖海鱼在越冬期的成活率。     

Modelling exposure of oceanic higher trophic-level consumers to polychlorinated biphenyls: Pollution ‘hotspots’ in relation to mass mortality events of marine mammals

Marine mammals in the past mass mortality events may have been susceptible to infection because their immune systems were suppressed through the bioaccumulation of environmental pollutants such as polychlorinated biphenyls (PCBs). We compiled mortality event data sets of 33 marine mammal species, and employed a Finely-Advanced Transboundary Environmental model (FATE) to model the exposure of the global fish community to PCB congeners, in order to define critical exposure levels (CELs) of PCBs above which mass mortality events are likely to occur. Our modelling approach enabled us to describe the mass mortality events in the context of exposure of higher-trophic consumers to PCBs and to identify marine pollution ‘hotspots’ such as the Mediterranean Sea and north-western European coasts. We demonstrated that the CELs can be applied to quantify a chemical pollution Planetary Boundary, under which a safe operating space for marine mammals and humanity can exist.