Paleodietary changes by penguins and seals in association with Antarctic climate and sea ice extent

Positioned near the top of the food web, the dietary composition of Antarctic penguins and seals can be an excellent indicator of the regional food web and thus the status of the marine ecosystem. The dietary composition of modern penguins and seals has been well investigated; a long-term time series of data on penguin and seal diets, however, are rare. Such data, especially any predating the initiation of human harvesting of fish, whales and seals in Antarctica, are crucial for understanding and predicting responses of regional marine food webs to natural climate changes. Here we review recent progress on research of paleodietary change in Antarctic penguins and seals, specifically the Adelie penguin （Pygoscelis adeliae） and Antarctic fur seal （Arctocephalus gazella）. These studies indicate that the dietary changes of penguins correspond quite well with fluctuations in climate and sea ice extent during the Holocene. The depleted δ15N ratios found in modern Adelie penguins support the ＂krill surplus hypothesis＂ in relation to historic human depletion of krilleating fish, seals and whales.     

Coexistence of two sympatric and morphologically similar bat species Rhinolophus affinis and Rhinolophus pearsoni

Ecologists have long focused on the coexistence of sympatric species. Here, we investigated two horseshoe bat species, Rhinolophus affinis and Rhinolophus pearsoni inhabited in the same cave, for their foraging strategies, niche differentiation, prey selection, and their coexistence status. These two species of horseshoe bats were different in the dominant frequency of their echolocation calls, but similar in their morphology. We found evidence for prey selectivity although there was a high degree of overlap in prey categories and sizes. R. affinis and R. pearsoni foraged on 16 and 7 categories insects, respectively, with Pyralidae, Geometridae, Melolonthidae dominating their diets. The degree of trophic niche overlap was 0.69. Pairwise comparisons suggested that there was no obvious differentiation in prey categories and size. However, high prey availability in the environment （Simpson diversity index = 0.79 and Margalef richness index = 4.12） contributed to their coexistence by dampening the interspecific competition. Since there are one or more mechanisms facil- itating species coexistence in a community, our results suggest that the spatial niche differentiation in foraging rnicrohabitats and in foraging habitats at landscape scale may promote the coexistence of the two bat species. However, additional field data are needed to confirm this speculation.     

Coexistence of two sympatric and morphologically similar bat species Rhinolophus affinis and Rhinolophus pearsoni

Ecologists have long focused on the coexistence of sympatric species. Here, we investigated two horseshoe bat species, Rhinolophus affinis and R. pearsoni inhabited in the same cave, for their foraging strategies, niche differentiation, prey selection, and their coexistence status. These two species of horseshoe bats were different in the dominant frequency of their echolocation calls but similar in their morphology. We found evidence for prey selectivity although there was a high degree of overlap in prey categories and sizes. R. affinis and R. pearsoni foraged on 16 and 7 categories insects, respectively, with Pyralidae, Geometridae, Melolonthidae dominating their diets. The degree of trophic niche overlap was 0.69. Pairwise comparisons suggested that there was no obvious differentiation in prey categories and size. However, high prey availability in the environment (Simpson diversity index = 0.79 and Margalef richness index ＝ 4.12) contributed to their coexistence by dampening the interspecific competition. Since there are one or more mechanisms facilitating species coexistence in a community, our results suggest that the spatial niche differentiation in foraging microhabitats and in foraging habitats at landscape scale may promote the coexistence of the two bat species. However, additional field data are needed to confirm this speculation.     

Spatio-temperial variations of the bacterioplankton community composition in Chaohu Lake, China

Despite considerable attention paid to Chaohu Lake in China, the dynamics of bacterioplankton community composition （BCC） on spatial and seasonal scales are poorly understood. In this study, water samples were collected from autumn 2006 to summer 2007 at five positions in Chaohu Lake with different trophic status. BCC of these samples was determined by both the PCR amplification of the 16S rDNA gene and the denaturing gradient gel electrophoresis （DGGE）. The abundance and diversity of bacterioplankton communities at different sampling positions showed similar seasonal patterns. The BCCs in the samples varied substantially, and the pattern of changes indicated that the seasonal difference might have a significant impact on the BCC＇s structure in the lake. Canonical correspondence analysis （CCA） on the DGGE patterns and physicochemical parameters indicated that the temperature and the levels of 5-d biochemical 02 demand （BODs）, NH3-N, CODMn, total nitrogen, total phosphorous, and dissolved oxygen significantly influenced the BCC, and four of the seven variables were related to the level of eutrophication. Our results indicate that eutrophic status and season are the most influ- ential factors in determining BCC in Chaohu Lake.     

Reconstructing past subsistence patterns on Zhongba Site using stable carbon and oxygen isotopes of fossil tooth enamel

The oxygen and carbon isotopic ratios in human and animal tooth enamel were measured to reconstruct the subsistence patterns on Zhongba Site between 2400 and 4200 aBP.The results indicate that human consumed chiefly C4 resources,such as millet,and the C3 plants,such as rice and wheat,constituted only a small fraction of the human diets,normally no more than 15%.There are significant differences in food sources between human and pig,and the percentages of C3 plants in pig diets were higher than those in human diets.But theδ13C values of pig partially overlap those of human,demonstrating some similarities in their food sources.The differences in water sources between human and pig are significant.There are significant differences in food and water sources between cattle and deer. This indicates that the two kinds of mammals subsisted in different niches.But theirδ13C values also partially overlap each other,suggesting some similarities in their food sources.There are both signifi- cant differences in meanδ13C andδ18O values between the omnivores,human and pig and the herbi- vores,cattle and deer,implying significant differences in food and water sources between the two categories.During the period the dietary habits of human had not changed,but the pig breeding strategies had changed,from breeding in house to breeding in confinement,and the proportion of C3 plants in pig food increased with time.The scope of human migration had been considerably large by the Warring States because of the development of productive forces.     

Ecological functioning of free-living marine nematodes in coastal wetlands: an overview

Nematodes are small multicellular, thread-like organisms, inhabiting almost all conceivable environments; among these, some 25 % are free-living marine forms with a population density of （1-12） × 10^6 inds m^-2 in seabed sediment, reaching maximum values in muddy estuaries and salt marshes. A large quantity of carbon from the salt marsh plants enters the ecosystem via the detritus pathway, in which nematodes play an important role through their feeding and bioturbation activities. Vegetation influences the sedimentary environment and modifies the distribution pattern of nematode communities in coastal wetlands. Nematodes are coupled closely with bacteria/detritus in microbial food webs, stimulating bacterial growth and subsequent nutrient remineralization; they provide food sources for higher trophic levels and serve as a linkage between micro- and macro-fauna. Furthermore, nematodes have a potential to provide proxies that can be used in diagnosing environmental quality. In China, only a limited number of nematode data sets are available for the coastal wetlands across several different climatic zones. It is necessary to carry out additional investigations into the biology and ecology of nematodes in order to delineate their ecological functioning in coastal wetlands. On such a basis, the contribution made by nematodes to material cycling and the ecological functioning in coastal wetlands can be quantified. The assessment of their biological diversity should be a focus, which is fundamental in the study of wetland ecosystem dynamic mechanisms. In addition to laboratory and mesocosm experiments, mathematical models should be established to predict the responses of ecosystem to the environmental disturbance. Finally, it is necessary to improve the techniques for nematode analysis, to enhance the efficiency of data acquisition.     

Natural diet and food habitat use of the Tarim red deer, Cervus elaphus yarkandensis

In order to determine the natural diet and food habitat use of Tarim red deer （Cervus elaphus yarkandensis）, a study was carried out in Qiemo, Xinjiang , China from October 2000 to June 2001. Direct observation combined with faecal analysis method was used to determine the natural diet of red deer. 15 different species of plant were identified as food items. Among them, 13 species of plants were identified in winter diet and 9 species in summer. Red deer consumed a wider range of species in winter because of their nutrient requirement as well as the shortage of food and the scarcity of high-quality forage in the study area. Phragmites communis, Glycyrrhiza inflata and populus diversifolia were frequently present in the deer＇s diet whenever in winter and summer. Among them, Phragmites communis was the most abundant plant in the area and was included in the deer＇s diet. Observation on food selection frequency of captive Tarim red deer showed that Populus diversifolia was the first preferred species. However, this food was limited in the study area. Five food habitat types were found in the study area according to plant association： （1） Phragmites communis-Tamarix ramosissima association, （2） Tamarix ramosissima-Halostachys caspica association, （3） Tamarix ramosissima-Phragmites communis association, （4） Populus diversifoliaPhragmites communis association, （5） Burned area. Among them, Phragmites communis-Tamarix ramosissima association （reed meadow and reed marsh） was preferred to other types within the study area whenever in summer and winter. Dense reed cover could reduce the chance of detection from predator and obstruct attack from predator. Furthermore, under the cover of the reed, Tarim red deer was protected from direct solar radiation during the hours of hot day in summer. The reed meadow and marsh was preferred, presumably because the red deer could minimize their movements while searching for food, water and cover.     

Natural diet and food habitat use of the Tarim red deer,Cervus elaphus yarkandensis

In order to determine the natural diet and food habitat use of Tarim red deer (Cervus elaphus yarkandensis), a study was carried out in Qiemo, Xinjiang , China from October 2000 to June 2001. Direct observation combined with faecal analysis method was used to determine the natural diet of red deer. 15 different species of plant were identified as food items. Among them, 13 species of plants were identified in winter diet and 9 species in summer. Red deer consumed a wider range of species in winter because of their nutrient requirement as well as the shortage of food and the scarcity of high-quality forage in the study area. Phragmites communis, Glycyrrhiza inflata and populus diversifo-lia were frequently present in the deer's diet whenever in winter and summer. Among them, Phragmites communis was the most abundant plant in the area and was included in the deer's diet. Observation on food selection frequency of captive Tarim red deer showed that Populus diversifolia was the first preferred species. However, this food was limited in the study area. Five food habitat types were found in the study area according to plant association: (1) Phragmites communis-Tamarix ramosissima association, (2) Tamarix ramosissima-Halostachys cas-pica association, (3) Tamarix ramosissima-Phragmites communis association, (4) Populus diversifolia-Phragmites communis association, (5) Burned area. Among them, Phragmites communis-Tamarix ramosissima association (reed meadow and reed marsh) was preferred to other types within the study area whenever in summer and winter. Dense reed cover could reduce the chance of detection from predator and obstruct attack from predator. Furthermore, under the cover of the reed, Tarim red deer was protected from direct solar radiation during the hours of hot day in summer. The reed meadow and marsh was preferred, presumably because the red deer could minimize their movements while searching for food, water and cover.     

Dietary toxicity of metals in aquatic animals: Recent studies and perspectives

Over the past decade,the quantitative recognition of the significance of dietary exposure in the overall bioaccumulation of metals in aquatic animals has been an area of major progress in metal ecotoxicology.In several major groups of marine animals such as predators and deposit-feeding animals,diet(food) is the predominant source for metal accumulation.The importance of trophic transfer raises very fundamental questions about its toxicity to aquatic animals and in setting water quality standards which go beyond waterborne metal exposure.Ten years of research on the dietary toxicity of metals in several groups of aquatic animals,including zooplankton and fish,is reviewed.It is suggested the future studies should attempt to incorporate the dosage rate or the dietary influx rate in the design of toxicology experiments to facilitate inter-comparison of the results of different studies.     

Stable isotopic analysis on sus bones from the Wanfabozi site, Tonghua, Jilin

In order to study the sus diets and explore the possibility to distinguish domestic pig from wild boar through dietary analysis, stable carbon and nitrogen isotopes of 28 pig bones from archaeological site of Wanfabozi in Tonghua City, Jilin Province were analyzed. The δ^13C and δ^15N values of uncontaminated bones show that the overall pigs in the site were generally herbivores and ate mainly C3 plants. Significant difference of δ^15N values was observed between wild boar and domestic pigs, which may result from the higher consumption of animal protein in domestic pigs other than from that in wild boar, possibly from human leftover or waste,. The dietary difference between wild boar and domestic pigs has great potential to differentiate wild boar and domestic pigs in the early stage of pig domestication.     

Effect of dietary supplementation on improvement of growth and immune function of broilers

The purpose of this investigation was to evaluate the effect of a dietary supplement （Mirigen TM）, a fungal cell wall derivative product, as a new generation alternative to antibiotics, on the growth and the innate and adaptive immune functions in broilers from birth to 45 d of age. Newborn chicken were randomly assigned to one of three groups： G 1 （n=150） controls no supplement fed; G2 （n=150） is fed with dietary supplement at a designed regular dose （0.5 %, weight of additive to food）; G3 （n= 150） is fed with dietary supplement at double doses （1%）. All three groups were housed in the same conditions. Body weight and blood were taken on day 1, 14, 28 and 45. Medications used and costs/treatment were recorded for each group. The whole blood was used to purify heterophils for reactive oxygen species （ROS） generation and E coli killing abilities examination assays, and the serum samples were preserved in freezer for enzyme linked immunosorbent assays （ELISAs） to determine concentration of macrophage inflammatory protein-1β （MIP-1β）, CD4/CD8, interferon-y （IFN-y）, and titers of antibody against Newcastle disease virus （NDV）. Group differences were analyzed using analysis of variance （ANOVA） algorithm （S-Plus）. There was no significant birth weight difference in three groups. After 45 d growth, the dietary supplement treated groups had significantly higher body weight gain （BWG） with lower mortality rate if compared to the untreated control group （P〈0.05）. Their BWG and mortality rate were 2.23 kg and 10 % in GI （control group）, 2.89 kg and 2 % in G2 （experimental group, 0.5 % dose）, and 2.77 kg and 1% in G3 （experimental group, 1% dose）, respectively. Heterophil ROS generation in treated groups were markedly improved through the addition of dietary supplement in both regular and double doses to the diet （P〈 0.05）. The ability of heterophil to kill E coli was also significantly improved in dietary supplement treated groups （P〈0.01）. Comparing to control group, there was significantly higher serum IFN-y concentration in treated groups （P〈0.05） on day 45. The CD4/CD8 was also improved in treated groups （P〈0.05）. Newcastle di-sease is the most prevalent avian disease, and vaccination is an effective method to protect the animals from the virus infection. In our study, it is found G2 and G3 that fed with dietary supplement had higher antibody titers against NDV after vaccination （P〈0.01） and the antibodies lasted longer. Results from this study demonstrated dietary supplement to broilers improved the immune capabilities of immune cells, which are vital to the establishment of immune response against pathogens, thereby, to improve chicken＇ s health and growth and reduce medication cost in chicken farming.     

Diet control on carbon isotopic composition of land snail shell carbonate

Carbon isotope compositions for both the carbonate shells and soft bodies (organic tissue) of living land snails collected mostly from the Loess Plateau, China have been measured. The result shows that δ 13C values range from -13.1‰ to -4.3‰ for the aragonite shell samples and from -26.8‰ to -18.0‰ for the soft body samples. Although the shells are enriched in 13C relative to the bodies averagely by 14.2(±0.8)‰, the shell δ 13Ca values are closely correlated to the body δ 13Corg values, expressed as δ 13Ca = 1.021 δ 13Corg 14.38 (R = 0.965; N = 31). This relationship indicates that δ 13Ca is primarily a function of the isotopic composition of the snail diets since previous studies have proved that the snail body is the same as their food in carbon isotope composition. In other words, carbon isotope compo-sition of the carbonate shell can be used as a proxy to estimate the dietary 13C abundance of the land snails. The data also support that the 13C enrichment of the carbonate shells results mainly from the equilibrium fractionations between the metabolic CO2, HCO3-in the hemolymph and shell aragonite, and partially from kinetic fractionations when snail shells form during their activity.     

Study of the Relationship Between the Organizational Climate and the Campus Ethical Issues of Universities across the Taiwan Strait

The study applied the approach of empirical studies to select 176 teachers in 9 universities in Taiwan and Inland in China to deliver questionnaires. The study intended to explore the influence of organizational climate on campus ethics and its diversity between the universities across the Taiwan strait. The study explored that the organizational climate in the universities across the Strait was not ethically high. Yet, the universities in Inland emphasized more on campus restraint in teachers‘ behavior, job performance and their sense of belonging to the school. The study result demonstrated that improving leadership of the universities could enhance teachers‘ identification with their schools and could promote the level of campus across the Strait.     

Genetic relationships among Chinese and American isolates of Phytophthora sojae assessed by RAPD markers

The genetic diversity of three geographic populations of Phytophthora sojae from China and the United States was determined using random amplified polymorphic DNA （RAPD）. The purpose was to explore genetic relationships among Chinese and American isolates of the organism. 21 random primers were selected among 200 random primers screened. A total of 223 reproducible RAPD fragments were scored among 111 individuals, of which 199 （89.23%） were polymorphic. Analysis of genetic variation showed that there existed higher genetic variation in the United States population in comparison to the Chinese populations. Nei＇s genetic identity and principal component analysis indicated that the populations of Fujian and United States are closer to each other than to Heilongjiang populations. Shannon-Wiener diversity index revealed that the United States populations have a higher genetic di- versity than that of Chinese populations. These data are in support of the hypothesis that P. sojae in the United States might not have been introduced from China.     

Analysis of carbon isotope in phytoliths from C3 and C4 plants and modern soils

The analysis of carbon isotope in phytoliths from modern plants and surface soils in China shows that the values of carbon isotope are consistent with those from C3 and C4 plants,and the processes of photosynthesis of the original plants can be clearly identified by carbon isotope in phytoliths.The value of carbon isotope varied from -23.8‰ to -28‰,with the maximum distributed in the latitude zone from 34° N to 40° N in North China and East China areas,and the minimum in the Northeast China and South China regions.The values of carbon of phytoliths tend to increase from low to high and then reduce to low value again as the latitude increases.In the same latitude zone,the carbon isotope in phytoliths from grassland soil under the trees is obviously lower than that from grassland soil without any trees with the difference of 1‰-2‰.     

Determination of trophic relationships within a Bohai Bay food web using stable δ15N and δ13C analysis

This study measured stable carbon and nitrogen isotope ratios in phytoplankton, zooplankton, five invertebrates species, eight fishes species and three seabirds species collected in Bohai Bay. δ^13C ranged from -25.38‰ to -11.08‰ showing a relative low enrichment in the food web from Bohai Bay. The mean δ^13C of mullet is higher than that of other organisms, and this might be due to that mullet is migration fish and feeds mainly on inshore sources. δ^15N ranged from 4.08‰ to 13.98‰, and showed a step-wise enrichment with trophic level of 3.8‰. The δ^15N enrichment factor was used to construct an isotopic food web model to establish trophic relationships within this marine food web. According to this model, exact trophic levels of all organisms were estimated as 1.46-2.10, 1.91-3.32, 2.55-4.23 and 2.98-4.28 for plankton, invertebrates, fishes, and seabirds.     

Genetic diversity in Penaeus chinensis shrimp as revealed by RAPD technique

The random amplified polymorphic DNA analysis was used to estimate genetic diversity in one successively cultivated stock and three wild stocks of Penaeus chinensis shrimp, two of which were collected from the spawning and wintering grounds in the west coast of Korean Peninsula, and one from the feeding ground in the China coast of the Yellow Sea. A random primer kit was employed to scan the genomic DNA in 20 individuals of each index stock. A total of 110 reproducible RAPD markers were obtained, 68.2 % of which showed a sound eonformability within all the individuals detected, implying that the genetic variability in P. chinensis is relatively low. The proportions of polymorphic loci among these four stocks ranged from 20% to 33.3%, while the degrees of genetic polymorphisms varied from 0.0093 to 0.0307. The genetic variability of inter-stocks was higher than that of intra-stock. The genetic diversity in different stocks differed from each other; that is, a less genetic differentiation in the spawning and wintering stocks from the west coast of Korean Peninsula was revealed and their genetic diversities were higher than that of the spawning stock in the Bohai Sea and the China coast of the Yellow Sea. As detected, the genetic diversity in the successively cultivated stock was the lowest among these four stocks. Through genetic distance analysis between a random pair of individuals, a dendrogram of the above-mentioned four stocks was constructed by unweighted pair group method with arithmetic mean. The results based on cluster analysis well fitted with the geographical distribution of P. chinensis in the Bohai and Yellow Seas.     

Climate change and hydrologic process response in the Tarim River Basin over the past 50 years

Climate change and hydrologic process response in the Tarim River Basin over the past 50 years are the focus of more and more researchers＇ attention. In this paper, both temperature and precipitation time series were found to present a monotonic increasing trend using nonparametric tests. Noticeably, a significant step change in both temperature and precipitation time series occurred in 1986. By contrasting the trends of natural water process in headstream and mainstream, we found that it was anthropogenic activities not climate change that caused the river dried up and vegetation degenerated in the lower reaches of Tarim River. The results of gray correlation analysis show that the runoff of higher latitude distributing river is more closely associated with winter snow stocking, while that of lower latitude is more closely related to summer temperature. Runoff in the headstream is more sensitive to precipitation, while that in the mainstream is more sensitive to evaporation. The strong evaporation caused by increasing temperature weakened runoff to some extent in spite of the fact that precipitation increased over the past 50 years.     

极端事件与影响评价:赞比亚干旱对其社会经济之影响(英文)

Objective--To investigate the effects of extreme events such as floods and droughts on social and economic activities in Zambia. Methods--The annual daily rainfall for stations, which have complete 40 years （1960-2000） time series of daily rainfall, is assigned to one of the five classes. class 1 （0-0.5 ram）, class 2 （0.5-5 mm）, class 3 （5-10 mm）, class 4 （10-25 ram） and class 5 〉25 ram）. Class 1 refers to dry days or nearly dry days where as classes 2 to 5 refer to wet days. Class 5 refers to high intensity rainfall days. The daily rainfall for the three Agro-Ecological zones is computed by averaging the daily rainfall of all the meteorological stations falling in each zone. Simple linear regression is performed to establish trends for the variables namely （i） annual number of days in each of classes from two to five, （ii） annual number of wet days and （iii） annual rainfall amount, for individual stations as well as for the three eco-climate zones. The student＇s t -tests are carried out to determine the significance of trends. The level of significance used in the trend analysis is set to 0.10. Results--This paper dwells on the drought trend in Zambia and its social and economic ramifications as it is exposed to the crises, stress and shocks arising from the fluctuating weather conditions. The food system in Zambia which has developed since the colonial period and has persisted even after the attain- ment of political independence in 1964 is increasingly becoming vulnerable to environmental shocks be- cause of the climate change and variability as maize the main staple food is more susceptible to extreme weather events as shown in this analysis of drought events. Trends for annual number of days in clas- ses three and four for all analyzed data are found to be negative indicating that days with rainfall intensity of 5-25 mm are decreasing at each of analyzed individual station and also in the three agro-ecological zones. Annual numbers of days of low intensity rainfall （0.5~-10 mm） in zone 1 are increasing pointing drier conditions. Annual number of days of high intensity rainfall （〉25 mm） are increasing in zones 2 and 3 indicating flooding conditions. Conclusion--Results have shown that drought can have dramatic deleterious effects on a country＇s socioeconomic, ecological as well as having some political ramifications as it affects stable flow of finances to government projects. For a small and intermediate economy like Zambia＇ s, it is very susceptible to draught episodes, because it is driven hy a large agricultural sector. That is, food availability and prices, employment, access to imports, government expenditures, availability of social services, and credit sources are all affected by drought.