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81.
Dye tracing of a subsurface chlorophyll maximum of a red-tide dinoflagellate to surface frontal regions 总被引:1,自引:0,他引:1
M. A. Tyler 《Marine Biology》1984,78(3):285-300
Rhodamine dye (3701) was injected into a 22-m subsurface chlorophyll maximum of the red-tide forming dinoflagellate Prorocentrum mariae-lebouriae var. minimum in the northern Chesapeake Bay (USA) and traced for a sixday period as it spread over a 600 km2 area. The precise physical mechanisms, which resulted in the transfer of dye and organisms to the surface, are documented. The major component of the dye and organisms was transported from the central bay into major tributary estuaries via net nontidal flow of bottom waters and surfaced upstream in frontal regions. Once in surface waters, the dye and organisms flowed downriver toward the bay. Due to the three-layer flow of the rivers at this time, the dinoflagellate and the rhodamine re-entered the bay proper at middepth below the fresher Susquehanna plume, thus forming a near-surface chlorophyll maximum (4–6 m) flowing in an opposite direction to the deep subsurface chlorophyll maximum (18–26 m). Current meter arrays verified the opposite flows of these two lenses. The near-surface, southward-flowing lens was followed downstream to an area where the influence of the Susquehanna begins to subside as indicated by isopycnals inclined to the surface. Here the near-surface lens is mixed upward to the surface forming massive red tides (25 000 cells ml–1) delineated by a frontal region. In addition to the predominant along channel flow, major cross stream Ekman transport and upwelling of dye and organisms was detected in response to wind forcing resulting in localized surface patch formation along the western shore shoaling regions of the bay proper. Thus, annual variations in the locations of surface red tides can be correlated to streamflow and windinduced variations in the locations of frontal regions. 相似文献
82.
Unhatched eggs were collected in 1988 and 1990 from nests of the Eurasian Dipper Cinclus cinclus and the Grey Wagtail Motacilla cinerea in Wales, eastern Scotland and south-western Ireland. Mercury concentrations in Dipper eggs (geometric means 0.45-0.91 ppm (microg g(-1)) dry mass) were significantly lower in eastern Scotland than in either south-western Ireland or Wales, where the incidence of detectable residues increased markedly between 1988 (2% of eggs) and 1990 (69%). By contrast, DDE (geometric means 0.63-3.54 ppm in lipid), TDE (<0.01-1.80 ppm), DDT (<0.01-0.65 ppm), total PCBs (3.99-10.47 ppm), HEOD (0.39-0.61 ppm) and HCB (0.02-0.13 ppm) were all significantly higher in Scottish eggs than others. Around 33-46% of the total PCB burden in Dipper and Grey Wagtail eggs could be accounted for by six congeners (IUPAC numbers 118, 180, 101, 153, 138 and 170). Amongst these attributable PCBs, Dipper eggs from eastern Scotland were dominated by congener 153 (2,2',4,4',5,5'-hexachlorobiphenyl), whilst Welsh and Irish eggs were dominated by congener 118 (2,3',4,4',5-pentachlorobiphenyl). With the latter exception, all the individual congeners were found at significantly higher concentrations in Scottish eggs than others. Grey Wagtail eggs were dominated by congeners 118 and 101 (2,2,4,5,5'-pentachlorobiphenyl). In general, these congeners are common, widespread, and dominant components in the eggs of other wild birds for which data are available. Consistent with the low to medium levels of contaminants found in Dipper eggs, there was only slight evidence of any toxic effects. These included moderate shell thinning in relation to increasing DDE, and some evidence that contaminants had contributed to egg failure. 相似文献
83.
84.
Xinhua Fu V. Benno Meyer-Rochow John Tyler Hirobumi Suzuki Raphael De Cock 《Chemoecology》2009,19(3):155-168
Larval defensive behaviour and eversible organ morphology were compared in the firefly species Luciola cruciata Motschulsky 1854, L. lateralis Motschulsky 1860, L. leii Fu et Ballantyne 2006, Lampyris noctiluca Linnaeus 1767, Pyrocoelia analis Fabricius 1801, P. pectoralis Oliver 1883, P. sp. and two Diaphanes species. In all cases the eversible organs are located on the pleural cuticle, dorsal to the spiracle, but there is considerable
variation between species in their number, size and shape. In La. noctiluca they are confined to the abdomen, whereas in the other species they also occur on the meta- and mesothorax. In La. noctiluca and the Pyrocoelia species the organs are columnar in shape, contrasting with the forked organs of the Luciola and Diaphanes species. The eversible organs of the Luciola species, which are all aquatic, are remarkably larger (relative to body length) than those of the other, terrestrial species.
On organ eversion the Luciola species emit an odour resembling pine oil, the Diaphanes species smell weakly of mint and L. noctiluca and the Pyrocoelia species produce no discernible scent, though ants are nonetheless repelled by contact with everted L. noctiluca organs. The organs of all the species studied support protuberances on their external surface, though these too vary in shape,
size and ornamentation between species. In all species except L. noctiluca each protuberance is connected to a well-developed globular body via a long, thick stalk. Circular foveae are located in
the centres of these globular bodies. The globular bodies consist of secretory cells characterized by the presence of numerous
mitochondria and an extensive system of cisternae and tubular endoplasmic reticulum. Behavioural tests revealed that small
larvae run away instead of becoming immobile and glowing, whereas large larvae start to glow when disturbed. The study shows
that the eversible larval organs form an important part of a defensive arsenal in the Lampyridae. 相似文献
85.
Despite widespread information on the incidence and biochemical effects of polychlorinated biphenyls (PCBs) in birds, field studies of effects on population processes are still scarce. This is particularly so in passerines. We therefore assessed breeding performance and post-fledging survival in dippers, Cinclus cinclus, breeding along the Afon Mule, a Welsh river where previous work indicated locally elevated PCB concentrations. We hypothesised that marked toxicological effects, including endocrine disruption, would be detectable as altered clutch-size, hatching success, nest success, brood-size, post-fledging survival or recruitment to the breeding population. Congener-specific analysis of PCBs in failed and deserted dipper eggs during 1990–93 revealed that geometric mean concentrations were four to 20 times higher along the Mule than elsewhere in Wales, UK. PCB signatures also varied highly significantly from other locations, with congeners 138, 153 and 180 dominant at the contaminated site, but 118 or 170 more frequent in eggs elsewhere. Subsequent analysis of surface runoff confirmed a small breaker's yard as a point source. Neither laying dates, clutch-sizes, brood-sizes, nest failure nor hatching failure along the contaminated Mule (n=46 breeding attempts and 218 eggs) differed significantly from dippers along adjacent reference rivers (n=82 breeding attempts and 315 eggs) or Welsh rivers as a whole (n=332 breeding attempts and 1534 eggs). Subsequent recaptures of breeding dippers ringed initially as nestlings were nearly identical between the Mule (7.7% of 182 nestlings), the reference set (7.5% of 323 nestlings) and all other Welsh rivers (7.3% of 2821 nestlings). These data illustrate the value of congener-specific analysis of bird's eggs in indicating local PCB sources. The data show also that PCBs can occur in dipper eggs at total concentrations of 0.49 (geometric mean)–1.29 (upper quartile) μg g−1 wet mass without effects on breeding performance and survival. These values are below those at which biochemical or reproductive effects on other passerines have been detected, but above current concentrations in any other population of European dippers for which PCB data are available. Population effects by PCBs on European dippers are therefore unlikely. Survivors from locally contaminated sites like that in our study might allow field assessments of second-generation effects on breeding performance in wild birds that have developed under PCB exposure. 相似文献
86.
Use of agricultural land evaluation and site assessment in Whitman County,Washington, USA 总被引:2,自引:0,他引:2
Melanie Tyler Liese Hunter Frederick Steiner Dennis Roe 《Environmental management》1987,11(3):407-412
Whitman County, Washington, USA, one of the largest wheat producing counties in the country, developed a land evaluation and site assessment system for evaluating proposed conversions of agricultural land to heavy commercial uses. The system uses soil potential indices to determine a land evaluation score and a nine-factor site assessment system to weigh suitability for development. Details on each of these are provided along with results for four sample sites.Scientific Paper no. 7165, College of Argiculture and Home Economics Research Paper, Washington State University, Pullman, Washington, project no. 0010. 相似文献
87.
In recent decades, there has been an increasing emphasis on proactive efforts to conserve species being considered for listing under the U.S. Endangered Species Act (ESA) before they are listed (i.e., preemptive conservation). These efforts, which depend on voluntary actions by public and private land managers across the species’ range, aim to conserve species while avoiding regulatory costs associated with ESA listing. We collected data for a set of social, economic, environmental, and institutional factors that we hypothesized would influence voluntary decisions to promote or inhibit preemptive conservation of species under consideration for ESA listing. We used logistic regression to estimate the association of these factors with preemptive conservation outcomes based on data for a set of species that entered the ESA listing process and were either officially listed (n = 314) or preemptively conserved (n = 73) from 1996 to 2018. Factors significantly associated with precluded listing due to preemptive conservation included high baseline conservation status, low proportion of private land across the species’ range, small total range size, exposure to specific types of threats, and species’ range extending over several states. These results highlight strategies that can help improve conservation outcomes, such as allocating resources for imperiled species earlier in the listing process, addressing specific threats, and expanding incentives and coordination mechanisms for conservation on private lands. 相似文献
88.
89.
90.
Chantel D. Sloan Tyler J. Philipp Rebecca K. Bradshaw Sara Chronister W. Bradford Barber James D. Johnston 《Journal of the Air & Waste Management Association (1995)》2016,66(1):53-65
Continued development of personal air pollution monitors is rapidly improving government and research capabilities for data collection. In this study, we tested the feasibility of using GPS-enabled personal exposure monitors to collect personal exposure readings and short-term daily PM2.5 measures at 15 fixed locations throughout a community. The goals were to determine the accuracy of fixed-location monitoring for approximating individual exposures compared to a centralized outdoor air pollution monitor, and to test the utility of two different personal monitors, the RTI MicroPEM V3.2 and TSI SidePak AM510. For personal samples, 24-hr mean PM2.5 concentrations were 6.93 μg/m3 (stderr = 0.15) and 8.47 μg/m3 (stderr = 0.10) for the MicroPEM and SidePak, respectively. Based on time–activity patterns from participant journals, exposures were highest while participants were outdoors (MicroPEM = 7.61 µg/m3, stderr = 1.08, SidePak = 11.85 µg/m3, stderr = 0.83) or in restaurants (MicroPEM = 7.48 µg/m3, stderr = 0.39, SidePak = 24.93 µg/m3, stderr = 0.82), and lowest when participants were exercising indoors (MicroPEM = 4.78 µg/m3, stderr = 0.23, SidePak = 5.63 µg/m3, stderr = 0.08). Mean PM2.5 at the 15 fixed locations, as measured by the SidePak, ranged from 4.71 µg/m3 (stderr = 0.23) to 12.38 µg/m3 (stderr = 0.45). By comparison, mean 24-h PM2.5 measured at the centralized outdoor monitor ranged from 2.7 to 6.7 µg/m3 during the study period. The range of average PM2.5 exposure levels estimated for each participant using the interpolated fixed-location data was 2.83 to 19.26 µg/m3 (mean = 8.3, stderr = 1.4). These estimated levels were compared with average exposure from personal samples. The fixed-location monitoring strategy was useful in identifying high air pollution microclimates throughout the county. For 7 of 10 subjects, the fixed-location monitoring strategy more closely approximated individuals’ 24-hr breathing zone exposures than did the centralized outdoor monitor. Highlights are: Individual PM2.5 exposure levels vary extensively by activity, location and time of day; fixed-location sampling more closely approximated individual exposures than a centralized outdoor monitor; and small, personal exposure monitors provide added utility for individuals, researchers, and public health professionals seeking to more accurately identify air pollution microclimates.Implications: Personal air pollution monitoring technology is advancing rapidly. Currently, personal monitors are primarily used in research settings, but could they also support government networks of centralized outdoor monitors? In this study, we found differences in performance and practicality for two personal monitors in different monitoring scenarios. We also found that personal monitors used to collect outdoor area samples were effective at finding pollution microclimates, and more closely approximated actual individual exposure than a central monitor. Though more research is needed, there is strong potential that personal exposure monitors can improve existing monitoring networks. 相似文献