苔藓土壤节肢动物群落及其多样性

苔藓土壤中分布着种类和数量丰富的节肢动物 ,主要是中、小型土壤动物。对上海市区苔藓土壤节肢动物群落进行了为期一年的调查研究 ,用 Tullgren分离装置 ,共收集土壤节肢动物 1 95 4 2只 ,隶属 5纲 1 1目 46科 5 8种。螨类和弹尾类共占总捕量的 97.4%,为苔藓土壤节肢动物的优势类群。螨类占苔藓土壤节肢动物种类的 74.2 %,个体数量的 79.7%,是苔藓土壤节肢动物群落的特征类群。优势种跗线螨 ( Tarsone-mus sp.)和真长须螨 ( Eustigmaeus clavated)均取食苔藓 ,并耐受低温 ,跗线螨占节肢动物总捕量的 45 %,真长须螨占 1 5 %。苔藓层节肢动物以螨类的前气门亚目为主 ,多为优势种和常见种 ,个体数量多 ,而土壤层节肢动物以螨类的隐气门亚目和弹尾类为主 ,种类较丰富。苔藓土壤节肢动物群落的多样性指数和优势集中性指数主要由螨类决定 ,受季节的影响明显 ,5月和 1 0月份多样性指数最高 ,1月份最低 ,而 1月优势集中性指数最高     

Hand-operated box sampler for shallow water

The construction and operation of a hand-operated box sampler is described. The sampler covers an area of 25 × 25 cm and penetrates into the sediment to the depth of 15 cm. It was successfully operated on a sandy bottom, and on sand mixed with gravel up to a water depth of 1 meter.IAEC, Yavne 70600, Israel     

A new quantitative air-lift sampler for collecting macroinvertebrates on stony bottoms in deep rivers

SUMMARY. 1. As three previous comparative studies of deep-water samplers for benthic macroinvertebrates in rivers highlighted the need for a quantitative sampler for use on stony substrata, a new air-lift sampler was developed. It can be operated from a small boat by two people, weighs 13.5–20.0 kg, depending on the length of riser used, and extends the maximum range of substrata that may be sampled quantitatively from 16–32 mm to 128—256 mm. The sampling area is isolated by forcing a collecting cylinder into the substratum, and rapid evacuation of the contents is assisted by a vibrator.
2. All the major specifications of the sampler were determined experimentally in a large tank using three sizes of substrata and plastic pellets to represent invertebrates. The sampler performed accurately to a depth of at least 8 cm on substrata ranging from gravel (2–4 mm) to large stones (32–36 mm long).
3. The performance of the sampler was compared with that of a Ponar grab and Pearson el at. air-lift sampler at two sites on a large river and also with a Naturalist's dredge and a diver-operated Hess-Waters sampler at one of the sites where there were large stones up to 280 mm long. In terms of both mean taxa per sample and mean numbers m⁻², samples taken using the new air-lift sampler provided estimates comparable to or belter than those obtained with the other samplers.     

Modification of a freshwater sampler using evacuated tubes for microbial collections

The modification of a freshwater sampler utilizing three evacuated tubes for the collection of microbial samples is described. To avoid contamination sterile hypodermic needles covered with rubber sleeves are inserted into the evacuated tubes prior to lowering the sampler. At the requisite depth each sleeve is pushed down over the end of the needle so that the tubes fill with water.     

A quantitative sampler for collecting invertebrates associated with deep submerged vegetation

Only few of the numerous samplers for collecting invertebrate fauna associated with vegetation permit sampling at depths of more than approximately 0.5 m. This paper describes a sampler allowing collection of epifauna from submerged plants at a depth of up to approximately 2 m, growing in varied densities. The sampler is composed of two panels made of duralumin, connected on one side by means of piano-hinges. One of the panels has an opening covered with mesh, and the other is equipped with a cone-shaped net and detachable sample concentrator at its end. The sampler is coupled with a manipulator with a several meter extension for lowering the sampler under water, as well as for its opening, and closing. The initial assessment of the sampler efficiency, verified in beds of Potamogeton perfoliatus, provided similar results as two other, older and commonly used samplers. In comparison with the older devices, the sampler has the advantage of permitting collecting samples from greater depths. It also enables studying both the vertical and horizontal distribution of invertebrates within a plant patch.     

Microscale patchiness of plankton within a sharp pycnocline

Microscale distributions of plankton around the pycnocline werestudied over a 24 h period in the southern Kattegat, using agradient sampler which collects 20 samples over a 3 m depthinterval. Moderately elevated concentrations of phyto- and zooplanktonwere observed at the pycnocline. Microscale variance was highestfor adult copepods. Nauplii and copepodites were equally wellrepresented by sampling with ordinary vertical 5 1 water bottlesas with the horizontal 1.5 1 bottles of the gradient sampler.Adult copepods were underestimated by the vertical bottles.No vertical migration of dinoflagellates was observed over the3 m interval covered by the gradient sampler. Microscale correlationsbetween copepods and phytoplankton within the gradient samplerwere weak. Copepodites (mainly Oithona sp.) and the dinoflagellateProrocentrum micans showed the best correlation.     

A comparative study of three air-lift samplers used for sampling benthic macro-invertebrates in rivers

SUMMARY. From 16 air-lift samplers described in the literature, three were selected for operation from a small boat: Mackey, Pearson et al. and Verollet & Tachet samplers. Random samples (number of sampling units n= 10) were taken in a large tank with a known number of dried peas, representing invertebrates, amongst stones of uniform size. Separate experiments were performed with three sizes of stones (modal sizes 2–4, 16–20 and 32–36 mm). Stratified-random samples (usually n= 10) were taken in rivers at lour sites with modal particle sizes of < 0.1 2–4. 32–128 and 64–128 mm. The samplers were compared with a Ponar grab in the tank experiments and the field, and with a Naturalist's dredge in the field. Rates of pumping at different air-flows were established for each sampler. Water-How increased with increasing air-How and increasing submergence of the riser-pipe. The Mackey sampler achieved the highest water-flow and lifted more substratum and larger stones (64–128 mm) than the other samplers. The Verollet & Tachet sampler had the lowest pumping rate and failed to lift stones > 8 mm long, whilst the Pearson et al. sampler, with an intermediate performance, lifted mud and stones < 32 mm long. In the tank experiments, the area from which the Mackey and Pearson et al. samplers collected peas varied with air-flow, operating time and type of substratum. The Maekey sampler over-sampled and the Pearson et al. sampler usually under-sampled their respective sampling areas, except the latter sampler at high air-flows gave approximately quantitative results comparable to those of the Ponar grab for peas on the surface of stones 16–20 mm. No sampler collected much at a depth of 3 cm on larger stones (32–36 mm), and the Verollet & Tachet sampler failed completely on all substrata. In field trials, the Mackey and Pearson et al. samplers provided good qualitative samples except on large stones (32–128mm). The Verollet & Tachet sampler lifted little material. The relative abundance of taxa often differed between samplers. Estimates of the number of invertebrates per m² differed widely between samplers except for the Pearson et al. and Ponar grab which gave similar quantitative results at three sites. Values were very low for the Verollet & Tachet sampler and Naturalist's dredge and always very high for the Mackey sampler which often grossly over-sampled its sampling area. Therefore, these three samplers cannot be considered as quantitative. The relationship between the variances and the means of samples of peas in the tank and most invertebrates in the field followed a power law with values of the exponent b in the range 1.13–2.51. The present study completes the evaluation of 14 samplers used to sample benthic macro-invertebrates in deep rivers, and the more important conclusions from the comparative studies of seven grabs, four dredges and three air-lift samplers are summarized in a table.     

A simple and inexpensive trap-tube sampler for zooplankton collection in shallow waters

The paper describes a new type of zooplankton sampler, which combines the concepts of the Pennak core sampler and the Schindler-Patalas plankton trap. The new sampler, called Trap Tube Sampler, consists of a PVC water pipe (1.5–2.0 m, long; 10 cm diameter) provided, at the bottom end, of a filtering unit and closing mechanism which alternatively closes the mouth of the tube and the mouth of the filtering unit. The new device is particularly suitable for collecting samples from the entire water column in shallow vegetated water bodies, fish ponds and mesocosm tanks.     

A personal sampler to monitor airborne particles of biological origin

Aerobiological studies are important in many fields, specifically in medicine as they enable the identification of those airborne particles of biological origin coming into contact with man. These data are useful to evaluate the cause-effect ratio, to prevent allergy, to adjust the dose of drugs. A personal sampler for aerobiological particles (PARTRAP FA 52) was handed over to eleven atopic patients for a monitoring day. The sampling room was placed at about 15 cm from nose and mouth. The patients also underwent the Prick test and RAST test. The personal sampler for aerobiological particles enables a qualitative and quantitative sampling of the air close to the patient. More allergenic particles were found with the aerobiological personal sampling as compared to the sensitisation shown by Prick test and RAST in the same patient. This sampling method can be useful to demonstrate the cause-effect ratio directly near the patient and, moreover and can be indicative for further clinical and immunological investigations.     

A QUANTITATIVE SAMPLER FOR SUBMERGED AQUATIC MACROPHYTES

SUMMARY

A simple rotary sampler, capable of quantitatively harvesting submerged aquatic macrophytes is described. The sampler can be operated from a boat and consists of a central rod with a specially designed cutting blade at the base, and collecting hooks to catch the cut material. The values obtained with this sampler were not significantly different (at the 95% level of probabality) from those obtained by manual cutting underwater. The rotary sampler has great advantages in terms of time, ease of positioning, and effort over hand cutting.     

A new sampler for collecting invertebrates in submerged vegetation

A new sampler is described that can rapidly enclose a specific volume of water at a given depth, including submerged macrophytes and associated invertebrates. The sampler is a tong-shaped instrument consisting of two metal rods connected by a flexible joint. At the end of each arm is a metal cylinder (diameter 10 cm); one end of the cylinder has a sharpened edge and the other is equipped with a net. Powerful metal springs force the cylinders together at high speed, and macrophytes are enclosed in the nets. The sampler is suitable for studying vertical and horizontal distribution of invertebrates, even fast-moving taxa, within submerged vegetation. The device causes little disturbance of the vegetation, hence it is also suitable for repeated sampling within mesocosms.     

The vertical distribution of macrobenthos within the substratum of the Brazos river,Texas

Vertical stratification samplers were developed for sampling the grave-sand substrate of a Brazos River, Texas riffle. Fifteen of 25 species recovered, occurred below 10 cm. Mean percentages of total organisms recovered were 66.4%, 20%, 6.1% and 7.5% per 10 cm level, respectively, from the surface down. Dominant insects were Neochoroterpes mexicanas naiads and chironomid, Simulium, Cheumatopsyche and Stenelmis larvae. Seasonal population peaks of these five groups in the top 10 cm correspond with observed emergence peaks. The smaller size classes were generally predominant in the 0–10 cm level. Larvae of Stenelmis were the most evenly distributed among the various 10 cm levels in all size classes. A movement of Cheumatopsyche and Neochoroterpes to lower levels was observed following a large flood, suggesting an escape response to increased silt load and scouring.Dissolved oxygen ranged from saturation at the surface down to 0.4–0.7 ppm at 30–40 cm, indicating that it was possibly limiting at lower levels. Maximum temperature difference between to cm levels was only 3 C. Flow was negligible below to cm.The vertical stratification sampler recovered significantly greater populations in the surface 20 cm, but not in the total 40 cm, than a modified Hess sq. ft. sampler.Study supported in part by the Faculty Research Fund and Institute for Environmental Studies of North Texas State University.     

A new sampler for extracting undisturbed surface peat cores for growth pot experiments

The sampler extracts uncompressed cores of 13·3 cm in diameter, up to 70 cm long, from the surface layers of peat. It has two close-fitting concentric cylindrical tubes, the outer one acting as a cutter and the inner one as a collector. As the outer tube is introduced by rotation into the peat, the cut core is collected in the inner tube which is maintained in a fixed position during the rotation phase and then pushed down stepwise. This limits friction between the peat core and the wall of the corer and prevents compression or distortion of the peat. These problems are also reduced by means of three skew cutters allowing the peat to be supported during the slicing action. Air can penetrate between the tubes to the lower end of the core, suppressing any suction effect during withdrawal. The sampler has been tested and has worked satisfactorily in many different peat types.     

Evaluation of a pumping system for sampling zooplankton

This study describes the sampling efficiency of a plankton pumpdesigned to operate from a moving research vessel. The samplingefficiency of the pump was evaluated by comparing the catchper unit volume of several planktonic taxa sampled simultaneouslywith the pump and with a modified Gulf V plankton sampler ora tube sampler. The estimates of plankton density obtained withthe pump sampler corresponded well with those obtained withthe modified plankton net and tube sampler. We conclude thatthe use of a plankton pump in zooplankton sampling gives resultscomparable to those found with traditional sampling, exceptthat the results were biased for the sampling of rotifers andcopepod eggs.     

A moorable,automated plankton sampler

A moorable, automated plankton sampler is described, designed to obtain series of plankton samples over extended time periods in the absence of a surface vessel. The sampler consists of one or more net-containing boxes, a unit for generating as well as measuring water flow through the net boxes, a programmeable control unit, and a frame. Each net box contains several nets on a vinyl strip, used to move the nets from the storage chamber into the fishing position and then into the preservative chamber. Preservation of samples is in a formalin-brine mixture.Net boxes can be added and the number of nets per box changed; the prototype is described with 1 net box with 10 nets. Volume of water to be filtered, time between sample collections, number of net boxes and the number of nets in each box is programmed into the control unit before sampler deployment. Collections made with the sampler are compared with those made with a SCOR net and a pump.     

The relation between dispersal and survival of Lobesia botrana larvae and their density in vine inflorescences

Dispersal and survival of Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae) larvae in a simulated first generation and the relationship with their density on vine inflorescences were studied under field conditions. Artificial infestations with neonate larvae were conducted at densities of 5, 10, 15, 20 and 25 individuals per vine inflorescence. Larvae had a considerable dispersal capacity on the vine espalier and were able to reach several inflorescences around those artificially infested. Dispersal downwards (63.1%) was significantly more frequent than upwards (36.9%), probably because larvae move down the vine plant using silk threads. However, the fact that there was upwards dispersal provides evidence that larvae are capable of active locomotion upwards on the vine plant structure. Mean distances covered by larvae ranged between 10 and 30 cm, with a maximum as far as 45 cm. The longest displacements were not associated with the downward dispersal. The maximum distance covered by larvae was positively correlated with larval density. Mean distance and larval density were not correlated, but mean distances covered at high larval densities were significantly higher than at low densities. At higher larval densities, the proportion of larvae which established in the artificially infested inflorescences decreased whereas the proportion of dispersing individuals increased. However, as a result of the balance between establishment and dispersal, larval survival did not differ significantly among larval densities (26–44%). The results obtained suggest that larval dispersal must be taken into account when preimaginal stages are sampled to determine whether damage thresholds are reached in an integrated pest management program.     

An efficient and quantitative aquatic benthos sampler for use in diverse habitats with variable flow regimes

A suction sampler designed to minimize sampling error, and quantitatively collect benthic macroinvertebrates from coarse substrata under various flow regimes is described. This sampler uses a 12 V bilge pump (capacity 4400 1 h^–1) to suck animals into a collecting net from substrata disturbed by a single operator. Macroinvertebrates were collected more rapidly by this sampler than by a Surber sampler or a Boulton suction sampler. Sources of sampling error are discussed for all three samplers. The electric pump sampler described here is suitable for sampling habitats where depth and velocity vary spatially and with time.     

Intrafraction esophageal motion in patients with clinical T1N0 esophageal cancer

Aim

To investigate the intrafraction movement of the esophagus using fiducial markers.

Evaluation of countermeasures for reduction of mouse airborne allergens

Three kinds of countermeasures for reduction of mouse airborne allergens were evaluated with use of an air sampler and immunochemical methods. Mouse cages and the sampler were placed inside a flexible-film isolator, and concentrations of mouse major allergens in the air were measured. The levels of the airborne allergens, prealbumin and albumin, generated by 10 males, were 3,050 and 492 pg/m3, respectively. Those by 10 females were lower, 317 and 270 pg/m3, respectively. When mouse cages were covered with a filter cap, the airborne allergens inside the isolator were decreased by 90%. When corncob was used as bedding in place of wood shavings, the airborne allergens were decreased by 57 and 77%, respectively. Therefore, for reduction of mouse airborne allergens, we recommend using female mice, covering the cages with filter caps, and using corncob bedding.     

集约化生产对农田土壤碳氮含量及δ13C和δ15N同位素丰度的影响

集约化生产下农田土壤碳、氮含量变化是衡量土壤肥力持久性的重要指标.对常规水稻-蚕豆轮作地、露地蔬菜地、3年塑料大棚地和10年以上塑料大棚地的土壤pH、电导率(EC)、土壤有机碳(SOC)和总氮(TN)含量及δ13C和δ15N同位素丰度进行测定,研究了集约化生产程度对土壤特性的影响.结果表明:与水稻-蚕豆轮作地相比,露地蔬菜地、3年塑料大棚地和10年以上塑料大棚地0 ～20 cm耕层土壤pH分别降低1.1、0.8和0.7,而土壤EC分别是水稻-蚕豆轮作地的4.2、4.9和5.2倍;土壤碳、氮含量随塑料大棚地生产年限的增加总体上呈先增大后减小的趋势.与水稻-蚕豆轮作地相比,10年以上塑料大棚地0～20、20～40、40 ～60、60 ～ 80、80 ～ 100 cm土层的土壤SOC含量分别下降了54％、46％、60％、63％和59％,土壤TN含量分别下降了53％、53％、71％、82％和85％.农田集约化生产程度显著影响土壤SOC、TN含量和δ13C、δ15N丰度,土壤δ13C丰度与SOC含量呈显著负相关.土壤δ13C丰度可作为评价农田土壤碳循环受人为干扰强度的指标.