基于五级态度量表的青海省国内游客满意度测评

提高游客满意度是促进旅游业可持续发展的根本保障.以青海省国内游客为研究对象,运用五级态度量表量化游客满意度评价项目,采用定性和定量相结合的方法,对餐饮、住宿、交通、游览、购物、娱乐、总体满意度以及游客重游率等方面开展综合测评.研究表明：国内游客对青海各旅游环节的满意度评价总体上处于满意和一般之间,旅游总体满意度评价较高,游客重游青海的潜力大.     

Diet and gill morphology of the East Coast redeye round herring Etrumeus wongratanai off KwaZulu-Natal,South Africa

Stomach content analyses and measurements of gillraker morphology were used to assess the diet and feeding ecology of the East Coast redeye round herring Etrumeus wongratanai and provide data for comparisons with other small pelagic fishes off South Africa. Samples were collected by jigging from a kayak off Scottburgh, KwaZulu-Natal (KZN), over the period July 2013–May 2014. In total, 66 stomachs (containing 4 407 prey items) and 66 gill arches were examined. Stomach content analyses indicated that East Coast redeye round herring, at the time of sampling, fed on large (1 500–2 500?µm) particles, with ～2 500?µm particles making the greatest contribution to dietary carbon. The species feeds on larger particles than do anchovy Engraulis encrasicolus and sardine Sardinops sagax, but on particles of a similar size to those consumed by West Coast redeye round herring Etrumeus whiteheadi. There were significant differences in mean gillraker gaps between East Coast redeye round herring and both sardine and anchovy, but not between East Coast and West Coast redeye round herring. The differences in gillraker gaps between East Coast redeye round herring, sardine and anchovy are indicative of resource partitioning through differential feeding, based on zooplankton size. The data suggest that there is no resource partitioning between East and West coast redeye round herring, indicating that competition is likely to occur between them. However, such competition is minimised by limited spatial overlap between these two species.     

Trophic ecology of small yellow croaker (Larimichthys polyactis Bleeker): stable carbon and nitrogen isotope evidence

The trophic ecology of the small yellow croaker (Larimichthys polyactis) was studied using stable isotope analyses. Samples were collected from July to September 2009 and 34 individuals from eight sites were examined for stable carbon and nitrogen isotopes. Stable carbon isotope ratios (δ13C) ranged from -20.67 to -15.43, while stable nitrogen isotope ratios (δ15N) ranged 9.18-12.23. The relationship between δ13C and δ15N suggested high resource partitioning in the sampling area. Significant differences in stable isotope values among the eight sampling sites may be linked to environmental diversities involving various physical processes (such as ocean current, wind and tide) and different carbon sources. Furthermore, the stable isotope ratios may also explain the ontogenetic variability in diet and feeding, because δ13C and δ15N varied significantly with increasing body size. The findings are consistent with other studies on diet analyses in small yellow croaker. It was also demonstrated that stable isotope analysis could be used to estimate the trophic characters of small yellow croaker in feeding patterns and migrating habits.     

Paleoenvironmental records of water level and climatic changes from the middle to late Holocene at a Lake Erie coastal wetland, Ontario, Canada

Pollen and diatom assemblages, and peat stratigraphies, from a coastal wetland on the northern shore of Lake Erie were used to analyze water level and climatic changes since the middle Holocene and their effects on wetland plant communities. Peat deposition began 4700 cal yr B.P. during the Nipissing II transgression, which was driven by isostatic rebound. At that time, a diatom-rich wild rice marsh existed at the site. Water level dropped at the end of the Nipissing rise at least 2 m within 200 yr, leading to the development of shallower-water plant communities and an environment too dry for most diatoms to persist. The sharp decline in water level was probably driven primarily by outlet incision, but climate likely played some role. The paleoecological records provide evidence for post-Nipissing century-scale transgressions occurring around 2300, 1160, 700 and 450 cal yr B.P. The chronology for these transgressions correlates with other studies from the region and implies climatic forcing. Peat inception in shallow sloughs across part of the study area around 700 cal yr B.P. coincides with the Little Ice Age. These records, considered alongside others from the region, suggest that the Little Ice Age may have resulted in a wetter climate across the eastern Great Lakes region.     

Carbonates calibrated against oceanographic parameters along a latitudinal transect in the Gulf of California, Mexico

Trophic resources are an important control governing carbonate production. Though this importance has long been recognized, no calibration exists to quantitatively compare biogenic assemblages within trophic resource fields. This study presents a field calibration of carbonate producers in a range of settings against high‐resolution in situ measurements of nutrients, temperature and salinity. With its latitudinal extent from 30° to 23° N, the Gulf of California, Mexico, spans the warm‐temperate realm and encompasses nutrient regimes from oligo‐mesotrophic in the south to eutrophic in the north. Accordingly, from south to north carbonates are characterized by: (i) coral‐dominated shallow carbonate factories (5–20 m water depth) with average sea‐surface temperatures of 25 °C (min. 18 °C, max. 31 °C), average salinities of 35·06‰ and average chlorophyll a levels, which are a proxy for nutrients, of 0·25 mg Chl a m^?3 (max. 0·48, min. 0·1). (ii) Red algal‐dominated subtidal to inner‐shelf carbonate formation (10–25 m) in the central Gulf of California exhibiting average temperatures of 23 °C (min. 18 °C, max. 30 °C), average salinities of 35·25‰, and average Chl a levels of 0·71 Chl a m^?3 (max. 5·62, min. 0). (iii) Molluskan bryozoan‐rich inner to outer shelf factories in the northern Gulf of California (20–50 m) with average sea surface temperatures of only 20 °C (min. 13 °C, max 29 °C), average salinities of 35·01‰, and average contents of 2·2 mg Chl a m^?3 (max. 8·38, min. 0). By calibrating sedimentological data with in situ measured oceanographic information in different environments, the response of carbonate producers to environmental parameters was established and extrapolated to carbonates on a global scale. The results demonstrate the importance of recognizing and quantifying trophic resources as a dominant control determining the biogenic composition and facies character of both modern and fossil carbonates.     

刘家峡水库西南部水域表层沉积物重金属污染评价

为了研究刘家峡水库西南部水域表层沉积物中重金属的污染状况,对采集的55个表层沉积物样品中的6种重金属元素Cr、Cd、Ni、Cu、Zn和Pb的含量进行测试,其平均含量分别为77.03μg/g、0.16μg/g、33.53μg/g、32.09μg/g、291.77μg/g、22.44μg/g。在研究表层沉积物重金属含量空间分布的基础上,运用单因子污染指数法、内梅罗综合污染指数法、地累积指数法、潜在生态风险指数法,综合判断水库的受污染程度并对其潜在生态风险进行评估。6种元素的地累积指数排序依次为：Zn > Cu > Cd > Ni > Pb > Cr;潜在生态风险系数排序依次为：Cd > Cu > Pb > Zn > Ni > Cr;各区域重金属污染程度或潜在生态风险水平依次为黄河主河道 > 大夏河河口 > 黄河横剖面。综合4种方法的评价结果,认为对刘家峡水库西南部表层沉积物重金属污染及潜在生态风险评价贡献率较高的重金属污染因子是Zn、Cu和Cd;综合相关性分析与主成分分析,认为研究区沉积物重金属污染主要来源于两个方面：（1） Zn、Cu主要来源于生活污染或工业污染;（2） Cd主要来源于工农业活动产生的污染。     

南海北部湾秋季蓝圆鲹与竹筴鱼的摄食生态及食物竞争

【目的】研究南海北部湾海域秋季蓝圆鲹与竹筴鱼的摄食生态特征和种间食物竞争。【方法】采用胃含物分析法,对2017年10月北部湾底拖网调查和港口随机取样收集的119尾蓝圆鲹(Decapterusmaruadsi)和198尾竹筴鱼(Trachurus japonicus)胃含物样品进行分析,通过肉眼直接观察或显微镜间接观察胃中残留的饵料,饵料种类鉴定、计数、称重等对食性做定量分析,以估算两种鱼类的营养级和生态位宽度,并利用生态位重叠研究两种鱼类的食物竞争关系。【结果与结论】蓝圆鲹的饵料种类19种(属),以桡足类和小型鱼类为主,优势饵料生物为布氏半棱鳀(Encrasicholinapunctifer);竹筴鱼的饵料种类18种(属),以小型鱼类和浮游甲壳类为主,优势饵料为中国毛虾(Acetes chinensis)。两种鱼类均为游泳动物食性,均存在摄食转换,随着叉长的增长,蓝圆鲹的饵料生物由小型浮游动物为主转变为小型鱼类为主,竹筴鱼的饵料生物由小型鱼类为主转变为以樱虾类和较大鱼类为主。蓝圆鲹和竹筴鱼的空胃率、竹筴鱼的平均胃饱满指数均随个体生长呈显著变化(P<0.05),但蓝圆鲹的平均胃饱满指数随个体生长无显著变化(P>0.05)。蓝圆鲹和竹筴鱼的营养级分别为3.63和3.40,营养生态位宽度分别为1.70和1.24,生态位重叠系数0.56,表明两种鱼类之间存在一定的食物竞争。     

A computational approach to Quaternary lake-level reconstruction applied in the central Rocky Mountains,Wyoming, USA

Sediment-based reconstructions of late-Quaternary lake levels provide direct evidence of hydrologic responses to climate change, but many studies only provide approximate lake-elevation curves. Here, we demonstrate a new method for producing quantitative time series of lake elevation based on the facies and elevations of multiple cores collected from a lake's margin. The approach determines the facies represented in each core using diagnostic data, such as sand content, and then compares the results across cores to determine the elevation of the littoral zone over time. By applying the approach computationally, decisions are made systematically and iteratively using different facies classification schemes to evaluate the associated uncertainty. After evaluating our assumptions using ground-penetrating radar (GPR), we quantify past lake-elevation changes, precipitation minus evapotranspiration (Δ_P−ET), and uncertainty in both at Lake of the Woods and Little Windy Hill Pond, Wyoming. The well-correlated (r = 0.802 ± 0.002) reconstructions indicate that water levels at both lakes fell at > 11,300, 8000–5500, and 4700–1600 cal yr BP when Δ_P − ET decreased to − 50 to − 250 mm/yr. Differences between the reconstructions are typically small (10 ± 24 mm/yr since 7000 cal yr BP), and the similarity indicates that our reconstruction method can produce statistically comparable paleohydrologic datasets across networks of sites.     

Long-term changes in the fish community structure from the Tsushima warm current region of the Japan/East Sea with an emphasis on the impacts of fishing and climate regime shift over the last four decades

Japanese fisheries production in the Japan/East Sea between 1958 and 2003 increased to their peak (1.76 million tons) in the late 1980s and decreased abruptly with the collapse of Japanese sardine. Catch results for 58 fisheries and various environmental time-series data sets and community indices, including mean trophic level (MTL) and Simpson’s diversity index (DI), were used to investigate the impacts of fishing and climate changes on the structure of the fish community in the Tsushima warm current (TWC) region of the Japan/East Sea. The long-term trend in fisheries production was largely dependent on the Japanese sardine that, as a single species, contributed up to 60% of the total production in the Japanese waters of the Japan/East Sea during the late 1980s. Excluding Japanese sardine, production of the small pelagic species was higher during 1960s and 1990s but lower during 1970s and 1980s. This variation pattern generally corresponds with the trend in water temperature, warmer before early 1960s and after 1990s but colder during 1970s and 1980s. The warm-water, large predatory fishes and cold water demersal species show opposite responses to the water temperature in the TWC region, indicating the significant impact of oceanic conditions on fisheries production of the Japan/East Sea. Declines in demersal fishes and invertebrates during 1970s and 1980s suggested some impact of fishing. MTL and DI show a similar variation pattern: higher during 1960s and 1990s but lower during 1970s and 1980s. In particular, the sharp decline during the 1980s resulted from the abundant sardine catches, suggesting that dominant species have a large effect on the structure of the fish community in the Japan/East Sea. Principal component analysis for 58 time-series data sets of fisheries catches suggested that the fish community varied on inter-annual to inter-decadal scales; the abrupt changes that occurred in the mid-1970s and late 1980s seemed to correspond closely with the climatic regime shifts in the North Pacific. These results strongly suggest that the structure of the fish community in the Japan/East Sea was largely affected by climatic and oceanic regime shifts rather than by fishing. There is no evidence showing “fishing down food webs” in the Japan/East Sea. However, in addition to the impacts of abrupt shifts that occurred in the late 1980s, the large predatory and demersal fishes seem to be facing stronger fishing pressure with the collapse of the Japanese sardine.