鲁中山区东亚三角头涡虫有性生殖过程研究初报

于2005年3-5月、9～11月对生活于鲁中山区的东亚三角头涡虫（Dugesia japonica）的有性生殖过程进行了研究,发现鲁中山区东亚三角头涡虫1年只有1次有性生殖过程。卵囊产出的高峰在4月,卵囊孵化与种群密度最高峰在5月,其有性生殖过程与温度、食物、虫体大小密切相关。经实验观察1个卵囊最多能孵出涡虫幼体10条,最少3条。     

Seasonal differences in plasma testosterone profiles in buffalo bulls

Testosterone was measured by radioimmunoassay in blood samples collected hourly over 10 h from two adult buffalo bulls in April, May, August and December. The basal concentrations were below 0.2 ng/ml while peak concentrations ranged from 0.35 to 1.65 ng/ml, with not more than one complete peak occurring during a 10 h period. Both bulls had similar testosterone profiles within each sampling period but differences were evident between periods, the mean concentration being highest in August and falling through December and April to the lowest levels in May. Testosterone concentrations in buffaloes are therefore lower than those in other domestic species, and appear to vary during different times of the year.     

Nutrient limitation and algal blooms in urbanizing tidal creeks

Tidal creeks are commonly found in low energy systems on the East and Gulf Coasts of the United States, and are often subject to intense watershed human development. Many of these creeks are receiving urban and suburban runoff containing nutrients, among other pollutants. During the period 1993-2001, we studied three tidal creeks located in southeastern North Carolina, a rapidly urbanizing area. All three creeks received anthropogenic nutrient loading. Oligohaline to mesohaline stations in upper tidal creek regions had much higher nutrient (especially nitrate-N) concentrations than lower creek areas, and hosted spring and summer phytoplankton blooms that at times exceeded 200 μg chlorophyll a l⁻¹. Phytoplankton biomass during winter was low at all stations in all three creeks. Spring and summer nutrient addition bioassay experiments were conducted to characterize the nutrients limiting phytoplankton growth. Water from high salinity stations in all three creeks always showed significant positive responses to nitrate-N inputs, even at concentrations as low as 50 μg N l⁻¹. Low salinity stations in upper creek areas often showed significant responses to nitrate-N inputs, but on occasion showed sensitivity to phosphorus inputs as well, indicating the influence of anthropogenic nitrate loading. During several experiments, one of the upper stations showed no positive response to nutrient inputs, indicating that these stretches were nutrient replete, and further phytoplankton growth appeared to be light-limited either by phytoplankton self-shading or turbidity. Water from upper creek areas yielded much higher chlorophyll a concentrations in bioassay experiments than did lower creek water. In general, these urbanizing tidal creeks were shown to be very sensitive to nitrogen loading, and provide a physical environment conducive to phytoplankton bloom formation in nutrient-enriched areas. Tidal creeks are important ecological resources in that they are considered to be nursery areas for many species of fish and shellfish. To protect the ecological function of these small, but very abundant estuarine systems, management efforts should recognize their susceptibility to algal blooms and focus on control of nonpoint source nutrient inputs, especially nitrogen.     

Effects of time and watershed characteristics on the concentration of Cryptosporidium oocysts in river water.

Water samples were collected from four locations on two rivers in Washington State and analyzed by membrane filtration-immunofluorescence assay to establish Cryptosporidium oocyst concentrations. Sampling locations were selected to evaluate effects of watershed character, from pristine mountain to downstream agricultural, on oocyst concentrations. Samples were collected at six biweekly intervals from late June to early September, with two additional sets of five samples taken on separate days (one set taken at bihourly intervals and one set taken simultaneously). Cryptosporidium oocysts were found in 34 of 35 samples at concentrations ranging from about 0.2 to 65 oocysts per liter. Oocyst concentrations were highest early in the sampling period, when they were influenced by postrainfall runoff, and decreased through the summer months. Oocyst concentrations found in ten samples collected on two days (5 samples per day) showed no short-term variations. Oocyst concentrations and oocyst production per square mile (ca. 2.6 km2) of watershed found in water draining a controlled public water supply watershed were the lowest observed. The concentrations and production rates for drainage from an adjacent, comparable, but uncontrolled watershed were nearly 10 times higher. The concentration and production rates of the downstream area influenced by dairy farming were nearly 10 times higher than rates at the upstream stations. The data showed clearly that oocyst concentrations were consistently observed above the detection limit of the analytical method, about 0.1 oocysts per liter; that oocyst concentrations were continuous as opposed to intermittent; and that watershed character and management affected surface water oocyst concentrations significantly.     

Effects of time and watershed characteristics on the concentration of Cryptosporidium oocysts in river water.

Water samples were collected from four locations on two rivers in Washington State and analyzed by membrane filtration-immunofluorescence assay to establish Cryptosporidium oocyst concentrations. Sampling locations were selected to evaluate effects of watershed character, from pristine mountain to downstream agricultural, on oocyst concentrations. Samples were collected at six biweekly intervals from late June to early September, with two additional sets of five samples taken on separate days (one set taken at bihourly intervals and one set taken simultaneously). Cryptosporidium oocysts were found in 34 of 35 samples at concentrations ranging from about 0.2 to 65 oocysts per liter. Oocyst concentrations were highest early in the sampling period, when they were influenced by postrainfall runoff, and decreased through the summer months. Oocyst concentrations found in ten samples collected on two days (5 samples per day) showed no short-term variations. Oocyst concentrations and oocyst production per square mile (ca. 2.6 km2) of watershed found in water draining a controlled public water supply watershed were the lowest observed. The concentrations and production rates for drainage from an adjacent, comparable, but uncontrolled watershed were nearly 10 times higher. The concentration and production rates of the downstream area influenced by dairy farming were nearly 10 times higher than rates at the upstream stations. The data showed clearly that oocyst concentrations were consistently observed above the detection limit of the analytical method, about 0.1 oocysts per liter; that oocyst concentrations were continuous as opposed to intermittent; and that watershed character and management affected surface water oocyst concentrations significantly.     

Microbial Load of Drinking Water Reservoir Tributaries during Extreme Rainfall and Runoff

Hygienic and microbiological examinations of watercourses are usually not carried out during heavy rainfall and runoff events. After rainfall or snowmelt, there are often massive increases in turbidity in flooding creeks in mountain ranges, which are frequently interpreted as an indication of microbial contamination. The aim of this study was to quantify the microbial loads of watercourses during such runoff events and to compare these loads with loads occurring during regular conditions. In a 14-month monitoring period we investigated the microbial loads of three tributaries of different drinking water reservoirs. A total of 99 water samples were taken under different runoff conditions and analyzed to determine physical, chemical, bacterial, and parasitic parameters. Thirty-two water samples were considered event samples during nine measuring series. The criteria for events, based on duration and intensity of precipitation, water depth gauge measurements, and dynamics, had been fixed before the investigation for each creek individually. Of the physical and chemical parameters examined, only the turbidity, pH, and nitrate values differed clearly from the values obtained for regular samples. Most of the bacteriological parameters investigated (colony, Escherichia coli, coliform, fecal streptococcal, and Clostridium perfringens counts) increased considerably during extreme runoff events. If relevant sources of parasitic contamination occurred in catchment areas, the concentrations of Giardia and Cryptosporidium rose significantly during events. The results show that substantial shares of the total microbial loads in watercourses and in drinking water reservoirs result from rainfall and extreme runoff events. Consequently, regular samples are considered inadequate for representing the microbial contamination of watercourse systems. The procedures for raw water surveillance in the context of multiple-barrier protection and risk assessment ought to include sampling during extreme runoff situations.     

Microbial load of drinking water reservoir tributaries during extreme rainfall and runoff

Hygienic and microbiological examinations of watercourses are usually not carried out during heavy rainfall and runoff events. After rainfall or snowmelt, there are often massive increases in turbidity in flooding creeks in mountain ranges, which are frequently interpreted as an indication of microbial contamination. The aim of this study was to quantify the microbial loads of watercourses during such runoff events and to compare these loads with loads occurring during regular conditions. In a 14-month monitoring period we investigated the microbial loads of three tributaries of different drinking water reservoirs. A total of 99 water samples were taken under different runoff conditions and analyzed to determine physical, chemical, bacterial, and parasitic parameters. Thirty-two water samples were considered event samples during nine measuring series. The criteria for events, based on duration and intensity of precipitation, water depth gauge measurements, and dynamics, had been fixed before the investigation for each creek individually. Of the physical and chemical parameters examined, only the turbidity, pH, and nitrate values differed clearly from the values obtained for regular samples. Most of the bacteriological parameters investigated (colony, Escherichia coli, coliform, fecal streptococcal, and Clostridium perfringens counts) increased considerably during extreme runoff events. If relevant sources of parasitic contamination occurred in catchment areas, the concentrations of Giardia and Cryptosporidium rose significantly during events. The results show that substantial shares of the total microbial loads in watercourses and in drinking water reservoirs result from rainfall and extreme runoff events. Consequently, regular samples are considered inadequate for representing the microbial contamination of watercourse systems. The procedures for raw water surveillance in the context of multiple-barrier protection and risk assessment ought to include sampling during extreme runoff situations.     

The mycoestrogen zearalenone in Portuguese flowing waters and its potential environmental impact

This study provides the first environmental risk assessment (ERA) for zearalenone (ZEN), the only known mycoestrogen, based on a broad-scale investigation on its occurrence in rivers and creeks from Portugal. Water sample filtration and immunoaffinity columns (IAC) clean-up followed by liquid chromatograph with tandem mass spectrometry (LC/MS ⁿ ) provided an analytical method with good analytical performance. ZEN levels were determined for seven Portuguese rivers and one creek, during two different seasons, in a total of 38 samples collected upstream wastewater treatment plants (WWTPs). Overall, 23.7% were contaminated with ZEN at levels ranging between 5.6 and 82.6 ng/L. The highest concentration was observed during spring, although no statistically significant differences were observed between spring and autumn sampling campaigns. The potential ecotoxicological risk from ZEN to different trophic levels of aquatic organisms was evaluated by means of risk quotients (RQs) calculation. Although all the RQs obtained were lower than 1, our results confirm that ZEN is a relatively frequent contaminant in flowing waters in Portugal and might contribute to the overall estrogenic activity in the environment.     

淡水排放对杭州湾湿地浮游动物群落分布的影响

于2010年4月至2011年1月对杭州湾南岸滩涂湿地5个断面(S1-S3为排水区, S4-S5为非排水区)的高潮位和中潮位分别进行浮游动物群落结构的周年调查, 共发现浮游动物38种(轮虫15种, 枝角类4种, 桡足类19种)。排水区浮游动物年平均密度88.89 ind./L, 生物量0.41 mg/L, 非排水区平均密度仅4.21 ind./L, 生物量0.10 mg/L。排水区轮虫和桡足类的第一优势种分别为萼花臂尾轮虫(Brachionus calyciflorus)和汤匙华哲水蚤(Sinocalanus dorrii), 而非排水区第一优势种为中华哲水蚤(Calanus sinicus)。S2-S3断面中潮位的水体营养盐浓度、浮游动物密度和生物量均明显大于高潮位。淡水排放、潮沟径流和潮汐决定了滩涂湿地群落的时空格局, 后两者还解释了排水区中、高潮位间群落结构组成的差异。       

Trace metals in Swedish natural fresh waters

Water samples were collected from unpolluted waters in southern and northern Sweden to show the range of natural trace metal concentrations. The results do not indicate any significant differences in metal levels between the two study areas. Negative correlations with pH exist for total concentrations of Cd, Pb, Al, Mn and Zn. The dissolved (dialysable) metal fractions also increase with increasing acidity. The concentration of humic substances influences the distribution of Fe, Mn, Al, Pb, Cr, Co and As, as shown by positive correlations with water colour.Increasing alkalinity has a limiting effect upon concentrations and annual fluctuations of Cd and Pb, and to some extent on Zn, in running waters.     

长江口东滩湿地斑尾刺虾虎鱼的栖息亚生境选择和食性差异

2015年7月至2016年6月每月在长江口东滩湿地西南水域的光滩、盐沼(以海三棱藨草为主)和潮沟3种亚生境进行斑尾刺虾虎鱼的样本采集,分析斑尾刺虾虎鱼的丰度和食性差异.结果表明:6—11月均采集到斑尾刺虾虎鱼样本,以幼鱼为主,其他月份未采集到.其中,7月采集数量最多,为71尾,11月仅采集到3尾.潮沟中共采集到93尾,分别是光滩和盐沼的5.2和4.9倍.6—11月斑尾刺虾虎鱼的平均体长和体质量均呈逐渐增加趋势.斑尾刺虾虎鱼主要摄食虾类、蟹类、昆虫类和多毛类等10大类30小类饵料生物.其中,虾类是最重要的饵料类别,并以安氏白虾等白虾属为主;蟹类以相手蟹属为主;昆虫类以小划蝽等蝽科昆虫成虫为主;鱼类饵料的质量百分比相对较高,但数量比例很低.不同亚生境斑尾刺虾虎鱼的饵料组成差异较大.7—11月斑尾刺虾虎鱼的摄食等级随体长增大而明显增大,秋末(11月)平均摄食等级可达3.不同亚生境间的斑尾刺虾虎鱼丰度差异与其摄食饵料不同有关.     

The distribution and abundance of planktonic penaeid larvae in Tudor creek,Mombasa, Kenya

The temporal distribution and abundance of penaeid prawn larvae in surface waters of Tudor creek were studied. Only late mysis and early post mysis stages of development were encountered in the creek waters with a descending gradient from the mouth station (station 1) to the innermost station 5. Larval encounter incidence (% incidence) was highest in plankton tows taken during night spring tides (59%) followed by night neap tides (45.4%), day spring tides (34.9%) and day neap tides (21.4%). This encounter incidence was more skewed towards the seaward stations (1 and 2) during the neap tides than during spring tides. Likewise, larval density (mean catch/standard 5 min. tow) decreased less steeply up the creek during spring tides than it did during neap tides. Higher catch rates were in general obtained in night samples than in day samples at each station and in each neap/spring phase. The diel cycle had a greater effect on both incidence and abundance of larvae than did the tidal cycle.Intensified larval incursion into the creek was observed between March and June.     

Reproductive monitoring of free-ranging female mountain gorillas by urinary hormone analysis

Frequent urine samples from three habituated free-ranging adult female mountain gorillas were collected during a four-week period in order to characterize, by analysis of urinary hormones, their ovarian cycle, and to diagnose pregnancy. A conceptive cycle and two cycles that did not result in full term pregnancy were monitored. Behavioral and physiological observations of mating and labial swellings were correlated to urinary hormone results. Mating occurred on days with elevated estrogens. Labial swelling was maximum near or at peak estrogen levels. Pregnancy was diagnosed at the field site by measurement of chorionic gonadotropin using commercially available human pregnancy detection kits. In one pregnancy, gestation length was 254 days. The pregnanediol glucuronide concentrations of the mountain gorilla did not change during the nonconceptive cycle. During the conceptive cycle, the concentrations did not increase until the approximate time of implantation. This finding suggests marked differences in steroid production or metabolism between the mountain gorilla and the captive lowland gorilla.     

Physical and chemical characteristics of the sediment in the estuarine region of Cananéia (SP), Brazil

Physical and chemical characteristics of sediment were analyzed at eight sampling areas in the estuarine region of Cananéia (SP), Brazil. The samples were collected in 1995 during four periods; summer, autumn, winter and spring. Total nitrogen and phosphorus concentrations, redox potential, water and organic matter percentage, sand and silt percentage and grain size were determined in six different layers of 20 cm deep columns of sediment. In general, the nutrient concentration and the percentage of organic matter decreased with depth and greater variations were observed in the first centimeter of the samples. Differences in nutrient concentration and organic matter were also observed during the study period. The highest concentrations were recorded during the rainy season (February) as a consequence of an accumulation of organic matter brought into the system by rivers and adjacent flooded areas. In general, the sediments had oxidized characteristics until the 5 or 10 cm depth in areas near the rich coastal vegetation. However, in areas open to the ocean, the entire sediment columns were almost completely oxidized.     

Influence of agricultural practices on nitrates in the water table aquifer

Water samples for nitrate testing were collected from over 200 wells in Kent and Sussex counties in Delaware over an 18-month period in areas with different agricultural land use. Nearly 70% of the wells were individual home water supplies. The rest of the wells, constructed from 3·2-cm diameter PVC pipe, were installed at selected locations. Water samples were also collected from monitoring wells around two potato-growing sites, on irrigated corn and soybean areas, a field spread with poultry manure, two animal-waste lagoon sites, and near stockpiled poultry manure.Certain agricultural activities cause higher nitrate concentrations in the ground water. Poultry manure has increased nitrate concentrations in the ground water in southern Delaware more than commercial fertilizer. Highest nitrate concentrations are found in areas with excessively well-drained soils. Some clay-lined, animal-waste lagoons may cause ground-water contamination. Potato growing in Delaware is not causing high nitrate concentrations in the water table aquifer because of the heavier soils that are not as susceptible to nitrite leaching.     

Variation in Eimeria oocyst count and species composition in weanling beef heifers

Rectal fecal samples were collected daily on 10 consecutive days in November 2004 from 11 weaned beef heifers to assess daily variation in fecal oocyst count and species composition. Subsequent samples were collected from the same animals on 15 April 2005 and 9 June 2005. Oocyst numbers were determined by the modified McMaster's test, and species were identified by examination of oocysts recovered with the Wisconsin sugar flotation technique. Soil samples were collected from the heifer pasture on 8 June 2005, and oocysts were quantified and identified to species. Mean fecal oocyst counts varied little at all sampling dates ranging from 134-377 oocysts/g. Ten Eimeria spp. were identified in fecal samples collected in November and April and 11 in June. Eimeria bovis was the most common species identified at all samplings. Mean species composition showed little variation during the 10-day sampling period in November, remained similar in April, and varied slightly in June. Twelve Eimeria spp. were identified in soil samples in proportions similar to those seen in fecal samples. The results indicate that clinically normal weanling beef heifers are likely to be infected with a diverse, but relatively stable, community of Eimeria spp.     

Does Biofilm Contribute to Diel Cycling of Zn in High Ore Creek, Montana?

Concentrations of metals cycle daily in the water column of some mining-impacted streams in the Rocky Mountains of the western USA. We hypothesized that biofilm in High Ore Creek, Montana, USA, sorbs and releases Zn on a diel cycle, and this uptake-and-release cycle controls the total and dissolved (0.45-μm filtered) Zn concentrations. We collected water samples from three sites (upstream, middle and downstream at 0, 350 and 650 m, respectively) along a 650-m reach of High Ore Creek during a 47-h period in August 2002 and from the upstream and downstream sites during a 24-h period in August 2003; we also collected biofilm samples at these sites. In 2002 and 2003, total and dissolved Zn concentrations did not exhibit a diel cycle at the upstream sampling site, which was ~30 m downstream from a settling pond through which the creek flows. However, total and dissolved Zn concentrations exhibited a diel cycle at the middle and downstream sampling sites, with the highest Zn concentrations occurring at dawn and the lowest Zn concentrations occurring during late afternoon (>2-fold range of concentrations at the downstream site). Based on (1) concentrations of Zn in biofilm at the three sites and (2) results of streamside experiments that demonstrated Zn uptake and release by na?ve biofilm during the light and dark hours of a photocycle, respectively, we conclude that Zn uptake in photosynthetic biofilms could contribute a large percentage to the cycling of Zn concentrations in the water column in High Ore Creek.     

Detection and distribution of rotavirus in raw sewage and creeks in São Paulo, Brazil.

Rotaviruses were concentrated from 8-liter samples of raw domestic sewage and sewage-polluted creek water by adsorption to and elution from positively charged microporous filters (Zeta Plus 60S), followed by ultracentrifugation of the filter eluates. Indirect immunofluorescence and direct immunoperoxidase methods allowed detection and enumeration of rotavirus in 6 (20.6%) of 29 sewage samples and in 19 (34.5%) of 55 creek water samples. Levels of rotaviruses ranged from < 3 to 63 focus-forming units (FFU)/liter, and the geometric means were 2.2 FFU/liter in sewage, 2.9 FFU/liter at creek Tremembé, and 2.6 FFU/liter at creek Pirajussara. Wastewater samples examined during autumn and winter months showed a higher rate positivity for rotavirus than those collected in spring and summer, corresponding to the seasonal variation of rotaviral diarrhea in the city of São Paulo.     

Seasonal LH profile in ovariectomized cattle

Two experiments were conducted to examine seasonal changes in circulating LH concentrations in ovariectomized heifers. In experiment 1, four Holstein heifers were ovariectomized in April 1977 during middiestrus. Blood samples were collected daily for 30 days surrounding each equinox and solstice for one year to examine changes in plasma LH levels at the time of seasonal photoperiod changes. The LH concentrations were highest during the winter solstice period and lowest during the summer solstice period. In addition, samples taken at two-week intervals indicated a distinct LH profile with maximal LH concentrations during November-April and minimal concentrations during May-October. In experiment 2, eight Holstein heifers were ovariectomized in June-July, 1979 and given an estradiol or a control implant in October. A distinct LH profile for the interval extending from January, 1980 to February, 1981 was found in the heifers that were not treated with estradiol. Concentrations were maximal during December-April and minimal during May-November. The LH profile followed a similar pattern in the estradiol-treated heifers; however, the overall profile was at a higher level. These data indicate that underlying seasonal reproductive mechanisms are present in cattle even though the species ovulates and breeds throughout the year.     

Potential sources of bacteriological pollution for two bays with marinas in Trinidad

Welcome Bay and Chaguaramas Bay in the northwest peninsula of Trinidad contain large marinas and smaller sections of bathing beaches. Bacteriological surveys were conducted at both bays to assess water quality and to determine potential sources of pollution. These surveys were conducted during the wet season of 1996 and the dry season of 1997. Eleven sample stations were established at Welcome Bay and 12 at Chaguaramas Bay. Freshwater samples were collected from rivers and drains within the survey area. Marine water samples were collected from marinas, bathing beaches and inshore and outer areas at both bays. Five water samples were collected from each sampling station during the wet season of 1996 and six during the dry season of 1997. The membrane filter technique was used to determine faecal coliform and Escherichia coli levels in all samples. There was a seasonal effect on water quality, with significantly higher faecal coliform levels in the wet season, when water quality was not in compliance with international standards. This represents a potential health risk in bathing areas. Water quality was better at the outer area of both bays. Water quality at the inner bay areas was most likely adversely affected by land-based sources of pollution identified in this study. These sources include three drains and two rivers, which discharged into the bays. Yachts were apparently not a source of sewage pollution: there was no significant relationship between yacht number and faecal coliform levels.