Between March 23 and April 4, 1981, samples were taken in the eastern tropical Pacific. The day/night vertical distribution
of euphausiid species and biomass are described and contrasted in detail on two eastern tropical Pacific stations, the DOME
station, in a region of continuous upwelling and the BIOSTAT station, in a nonupwelling area. The effects of various biological
parameters, such as temperature, salinity and oxygen concentrations on the distributions of the species are examined. The
numbers of euphausiids m-2 on both stations were highest during the day, indicating that avoidance of the sampler was not a problem. During the day
the largest concentration of adult euphausiids was between 300 and 350 m whereas the juveniles were concentrated between 170
and 80 m on both stations. Very few individuals were found within the oxygen minimum layer, but low concentrations of some
species were found below the oxygen minimum down to 1 000 m. At night the euphausiid concentration migrated upward into the
mixed layer (20 to 30 m) at BIOSTAT and to the base of the mixed layer at the DOME. Significant differences in the night depths
of the species were found on both stations. The oxygen minimum layer appeared to act as a barrier to the vertical distribution
of all species. Only two species were found in water with an oxygen concentration of <0.1 ml O2 l-1. Twentyone species of euphausiids were found on the two stations but the adult population was dominated by only two or three
species on both stations. The reproductive state of the species suggested that some species reproduced earlier on the DOME
than on BIOSTAT. Analysis of the depth distribution by cluster analysis showed that the most abundant species occupied different
depths during the night and day at BIOSTAT but the two most abundant species were concentrated at the same depth at the DOME
station although portions of each species population occupied different pelagic zones. 相似文献
The ability of 15 species of Atlantic reef corals to act as suspension feeders was demonstrated by their removal of suspended particles from sea water in culture vessels. Mean clearance rates varied from 16.6 to 145.5 ml water cleared/h/cm2 of live coral tissue. The lowest rates was found in Porites porites which is primarily a tentacle feeder, and the highest in Diploria clivosa which acts as both a tentacle feeder and suspension feeder. Rates of particle clearance in Agaricia agaricites, which is primarily a suspension feeder, were influenced by current velocity and type of food. 相似文献
Two complete collections of the fishes residing on an isolated coral patch reef ( 1500 m2) at Oahu, Hawaii, were made 11 years apart. Of the 112 species of fishes in both collections combined, only 40% were in common, but these made up more than 85% of the wet biomass in each collection. The two assemblages of fishes were similar in trophic structure and standing crop. Many coral reef fish communities are dominated by carnivorous forms. In the present study, planktivorous fishes were the most important trophic group in the community; this was related to abundant zooplankton resources. Following the second collection in 1977, recolonization by fishes was followed for 1 year. Recolonization proceeded rapidly and was primarily by juvenile fishes well beyond larval metamorphosis. Within 6 months of the second collection, the trophic structure had been re-established. The MacArthur-Wilson model of insular colonization described the recolonization process and predicted an equilibrium situation in less than 2 years. The recolonization data suggested that chance factors may explain the colonization process on a small scale, but a relatively deterministic pattern emerged when considering the entire reef. Thus, at the community level the fishes are a persistent and predictable entity. 相似文献
The abundance, composition and trophic relationships of metazoan leaf epifauna of the marine angiosperm Thalassia testudinum König were studied in Barbados, West Indies. Approximately 90 species from 11 phyla consisted chiefly of nematodes, harpacticoid copepods, crustacean nauplii, ostracods, and turbellarians. Epiflora- and detritus-feeders dominated the epifauna. Increasing leaf epiphytism was accompanied by faunal changes, most notably increased nematode, harpacticoid and polychaete density. Faunal composition was very similar to that of the temperate seagrass analogue Zostera marina. 相似文献
Particulate and water-soluble agents were tested to determine their ability to affect the relationship between metal toxicity and the survival of Euchaeta japonica (Copepoda, Calanoida). Clay minerals and diatoms were two types of particles capable of affecting this relationship. Ascorbic acid, sewage effluent, and water extracts of humic acid and two types of soils exhibited the same capability. The ability of the water-soluble agents was compared with that of a known chelating agent in an attempt to quantify the activity of the agents. 相似文献
A comprehensive understanding of sexual selection requires knowledge of the traits and mechanisms responsible for increasing a male’s paternity share (proportion of progeny sired) relative to that of other males mating with the same female. In this study we manipulated by starvation the expression of traits that might influence male paternity share in Tribolium castaneum. We then conducted experiments to examine how male starvation affects male performance during sequential episodes of sexual selection from mating to progeny production, and investigated female control over specific stages by using live vs dead females. Comparison of starved vs fed males revealed that T. castaneum females have control over spermatophore transfer during mating, as live females rejected inseminations by starved (“low quality”) males. None of the measured male copulatory behaviors (leg-rubbing frequency, asymmetry, and percent of time spent rubbing) affected the probability of successful insemination, but the last two were positively associated with male paternity share. Spermatophore positioning within the female reproductive tract was not affected by male treatment (starved/fed), by female treatment (live/dead), or by male copulatory behaviors. Starvation, however, had a dramatic effect on male reproductive physiology, decreasing both accessory gland size and total number of sperms transferred (but not sperm viability in seminal vesicles). In addition, females who mated to starved males stored fewer sperms in their spermathecae, which, together with decreased ejaculate size, may explain the reduced paternity share of starved males compared to fed males. This study elucidates some cryptic mechanisms influencing male reproductive success and aids our understanding of trait evolution through sexual selection. 相似文献
Objective: Self-report measures are typically used to assess the effectiveness of road safety advertisements. However, psychophysiological measures of persuasive processing (i.e., skin conductance response [SCR]) and objective driving measures of persuasive outcomes (i.e., in-vehicle Global Positioning System [GPS] devices) may provide further insights into the effectiveness of these advertisements. This study aimed to explore the persuasive processing and outcomes of 2 anti-speeding advertisements by incorporating both self-report and objective measures of speeding behavior. In addition, this study aimed to compare the findings derived from these different measurement approaches.
Methods: Young drivers (N = 20, M age = 21.01 years) viewed either a positive or negative emotion–based anti-speeding television advertisement. While viewing the advertisement, SCR activity was measured to assess ad-evoked arousal responses. The RoadScout GPS device was then installed in participants' vehicles for 1 week to measure on-road speed-related driving behavior. Self-report measures assessed persuasive processing (emotional and arousal responses) and actual driving behavior.
Results: There was general correspondence between the self-report measures of arousal and the SCR and between the self-report measure of actual driving behavior and the objective driving data (as assessed via the GPS devices).
Conclusions: This study provides insights into how psychophysiological and GPS devices could be used as objective measures in conjunction with self-report measures to further understand the persuasive processes and outcomes of emotion-based anti-speeding advertisements. 相似文献
The semiconductor industry plays a leading role in supporting economic stabilization and social progress in Taiwan. In this paper, Eco-indicator 95 and Impact 2002+ are utilized to evaluate the potential environmental impacts from five production processes of the double data rate synchronous dynamic random access memory (DDR SDRAM). The comparisons between these two impact methods and their scopes are also discussed.From our results, global warming potential and non-renewable energy consumption were identified as the major environmental impacts. Applications of Eco-indicator 95 and IMPACT 2002+ also suggest that summer smog and respiratory inorganics are significant impact categories. The comparison of the scopes of these two methods identifies that low GWP potential PFCs substitution and electricity saving are effective ways to decrease environmental impacts of DRAM manufacturing. In addition, IMPACT 2002+ is a more applicable LCA method for the semiconductor industry in Taiwan due to the structure and reference area of this method and the characteristics of the semiconductor industry in Taiwan. 相似文献
It is gratifying to report that 1975-1976 has been another year of increased activity for the Air Pollution Control Association, and various indicators are positive compared to previous years. Membership has increased, attendance at meetings has increased, we have a substantial surplus to report, there is increased activity in membership interest and in our overall activity. Public affairs involvement has increased somewhat, as have our international activities. Local sections and technical committees have expanded their scope of productive involvement. Clearly, APCA has had a successful and productive year. 相似文献
Peterson and Sabersky1 measured the concentrations of ozone, carbon monoxide, nitrogen oxide, and oxides of nitrogen under standard driving conditions in the Southern California area. They indicate that in an automobile with no inside source of carbon monoxide (CO), the interior concentrations will reflect those on the outside but in a more gradual manner. They did not record the rapid variations and high peaks in the interior that they did when samplings were taken from the outside. They reported that 25 ppm of CO was not often exceeded and the highest concentration of CO encountered was 45 ppm for a period of 3 min. 相似文献