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171.
Mussels have been widely used as bioindicators of coastal contamination, and recent reports have demonstrated that metals are accumulated from both the dissolved phase and from ingested food. In the winter and spring of 1995, we examined the influence of the chemical composition of food (protein content, trace element concentrations and ratios in the diatom Thalassiosira pseudomana) on the assimilation of six trace elements (Ag, Am, Cd, Co, Se and Zn) in the mussel Mytilus edulis (L.). Differences of up to 38% in diatom protein content had no major influence on the assimilation of any trace element or carbon. Protein assimilation in M. edulis examined with a 35S radiotracer was also independent of protein content in the diatoms. Similarly, Se assimilation in mussels was not affected by the different Se concentrations in the diatoms. Cd assimilation increased with increasing Cd concentration, presumably due to higher desorption of Cd under acidic conditions typical of the mussel gut. Zn assimilation was inversely related to Zn concentration in the food particles, implying a partial regulation of this metal in the mussels. There was no evidence of any interaction of Cd and Zn in their assimilation by the mussels. These results suggest that mussels are highly responsive, in an element-specific way, to some components of ingested food (e.g., metal concentration), but other food components (such as the biochemical composition of the algae) have little effect on assimilation. 相似文献
172.
Steve Carver Ian Convery Sally Hawkins Rene Beyers Adam Eagle Zoltan Kun Erwin Van Maanen Yue Cao Mark Fisher Stephen R. Edwards Cara Nelson George D. Gann Steve Shurter Karina Aguilar Angela Andrade William J. Ripple John Davis Anthony Sinclair Marc Bekoff Reed Noss Dave Foreman Hanna Pettersson Meredith Root-Bernstein Jens-Christian Svenning Peter Taylor Sophie Wynne-Jones Alan Watson Featherstone Camilla Fløjgaard Mark Stanley-Price Laetitia M. Navarro Toby Aykroyd Alison Parfitt Michael Soulé 《Conservation biology》2021,35(6):1882-1893
There has been much recent interest in the concept of rewilding as a tool for nature conservation, but also confusion over the idea, which has limited its utility. We developed a unifying definition and 10 guiding principles for rewilding through a survey of 59 rewilding experts, a summary of key organizations’ rewilding visions, and workshops involving over 100 participants from around the world. The guiding principles convey that rewilding exits on a continuum of scale, connectivity, and level of human influence and aims to restore ecosystem structure and functions to achieve a self-sustaining autonomous nature. These principles clarify the concept of rewilding and improve its effectiveness as a tool to achieve global conservation targets, including those of the UN Decade on Ecosystem Restoration and post-2020 Global Biodiversity Framework. Finally, we suggest differences in rewilding perspectives lie largely in the extent to which it is seen as achievable and in specific interventions. An understanding of the context of rewilding projects is the key to success, and careful site-specific interpretations will help achieve the aims of rewilding. 相似文献
173.
The hydrothermal vent vestimentiferans Riftia pachyptila Jones, 1981 and Ridgeia piscesae Jones, 1985 live in habitats with different abundances of external CO2. R. pachyptila is found in areas with a high input of hydrothermal fluid, and therefore with a high [CO2]. R. piscesae is found in a range of habitats with low to high levels of hydrothermal fluid input, with a correspondingly broad range of
CO2 concentrations. We examined the strategies for dissolved inorganic carbon (DIC) use by the symbionts from these two species.
R. pachyptila were collected from the East Pacific Rise (9°50′N; 104°20′W) in March 1996, and R. piscesae were collected from the Juan de Fuca Ridge (47°57′N; 129°07′W) during September of 1996 and 1997. The differences in the
hosts' habitats were reflected by the internal pools of DIC in these organisms. The concentrations of DIC in coelomic fluid
from R. piscesae were 3.1 to 10.5 mM, lower than those previously reported for R. pachyptila, which often exceed 30 mM. When symbionts from both hosts were incubated at in situ pressures, their carbon fixation rates increased with the extracellular
concentration of CO2, and not HCO3
−, and symbionts from R. piscesae had a higher affinity for CO2 than those from R. pachyptila (K
1/2 of 7.6 μM versus 49 μM). Transmission electron micrographs showed that symbionts from R. piscesae lack carboxysomes, irrespective of the coelomic fluid [DIC] of their host. This suggests that the higher affinity for CO2 of R. piscesae symbionts may be their sole means of compensating for lower DIC concentrations. The δ13C values of tissues from R. piscesae with higher [DIC] in the coelomic fluid were more positive, opposite to the trend previously described for other autotrophs.
Factors which may contribute to this trend are discussed.
Received: 24 September 1998 / Accepted: 12 May 1999 相似文献
174.
Belden JB Lotufo GR Chambliss CK Fisher JC Johnson DR Boyd RE Sims JG 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1363-1368
To determine if trinitrotoluene (TNT) forms nonextractable residues in earthworms and to measure the relative degree of accumulation as compared to TNT and its deaminated metabolites, Eisenia fetida was exposed to 14C-TNT using dermal contact to filter paper or exposure to soil. Nonextractable residues made up 32-68% of total body burden depending on exposure media and depuration time. Parent TNT accounted for less than 3% of radioactivity, while ADNTs accounted for 7-38%. Elimination half-lives were 61-120 h for TNT, ADNTs, and DANTs, which was significantly lower than the half-lives found for nonextractable residues, 201-240 h. However, over 80% of the nonextractable residue was solubilized using weak acid (pH 2). Based on our findings that TNT accumulation occurs primarily as nonextractable residues, which have a longer half-life, and that nonextractable residues can be solubilized, we propose that nonextractable residues could be used as a selective biomarker for assessing TNT contamination. 相似文献
175.
Fei Gao Gary Feng Ying Ouyang Huixiao Wang Daniel Fisher Ardeshir Adeli Johnie Jenkins 《Journal of the American Water Resources Association》2017,53(4):791-808
It is often necessary to find a simpler method in different climatic regions to calculate reference crop evapotranspiration (ETo) since the application of the FAO‐56 Penman‐Monteith method is often restricted due to the unavailability of a comprehensive weather dataset. Seven ETo methods, namely the standard FAO‐56 Penman‐Monteith, the FAO‐24 Radiation, FAO‐24 Blaney Criddle, 1985 Hargreaves, Priestley‐Taylor, 1957 Makkink, and 1961 Turc, were applied to calculate monthly averages of daily ETo, total annual ETo, and daily ETo in an arid region at Aksu, China, in a semiarid region at Tongchuan, China, and in a humid region at Starkville, Mississippi, United States. Comparisons were made between the FAO‐56 method and the other six simple alternative methods, using the index of agreement D, modeling efficiency (EF), and root mean square error (RMSE). For the monthly averages of daily ETo, the values of D, EF, and RMSE ranged from 0.82 to 0.98, 0.55 to 0.98, and 0.23 to 1.00 mm/day, respectively. For the total annual ETo, the values of D, EF, and RMSE ranged from 0.21 to 0.91, ?43.08 to 0.82, and 24.80 to 234.08 mm/year, respectively. For the daily ETo, the values of D, EF, and RMSE ranged from 0.58 to 0.97, 0.57 to 0.97, and 0.30 to 1.06 mm/day, respectively. The results showed that the Priestly‐Taylor and 1985 Hargreaves methods worked best in the arid and semiarid regions, while the 1957 Makkink worked best in the humid region. 相似文献
176.
Nicholas E. Manos M.A Gail F. Fisher M.A 《Journal of the Air & Waste Management Association (1995)》2013,63(1):5-11
Atmospheric pollution by sulfur oxides is discussed in terms of the sources of the pollutant and the possible methods of control. Possible approaches to control are classified in general categories, including fuel desulfurization, process modifications, and flue-gas desulfurization. Some of the more promising specific possibilities are discussed in relation to the organizations developing them. 相似文献
177.
G. E. Fisher T. A. Huls 《Journal of the Air & Waste Management Association (1995)》2013,63(10):666-671
The Saltzman Phenoldisulfonic Acid and Nondispersive Infrared methods have been compared for the determination of oxides of nitrogen in automobile exhaust. The main purpose of this investigation was to determine whether the Nondispersive Infrared method could be used as a possible replacement for the Saltzman method. Results show that the Nondispersive Infrared analyzer can be used to measure NOx in exhaust gases with advantages over both the Saltzman and Phenoldisulfonic Acid methods. These advantages include simplicity, speed, less complicated analytical technique, and the fact that it is better adapted to be carried out by technicians at the test site. 相似文献
178.
The Honorable Joseph L. Fisher 《Journal of the Air & Waste Management Association (1995)》2013,63(9):910-912
The subject of energy choices and public policy is one that has interested me at a professional level. The outlook for energy supply for Americans is uncertain. Will the OPEC crank the per barrel price of world oil up again this fall by three or four dollars? We don’t know. Will the cost of finding and developing new domestic oil reserves continue to rise, and will the domestic production continue to fall as it has been doing since 1970? We don’t know. Would regulating the price of old oil and natural gas entering into interstate commerce bring forth significantly increased supplies? We don’t know. The chances for reducing oil consumption—or at least checking the rate of increase—are equally uncertain. Will still higher prices, brought on by whatever means, cause people and industries to use less oil? We don’t know. Will demand shift away from oil and natural gas to cheaper, more plentiful energy sources? We don’t know. Will penalties, taxes, or exhortations get the motor vehicle industry to produce more gasoline efficient cars and trucks? We don’t know. We may not even get a chance to try. Will new, less energy intensive lifestyles take over? We don’t know. 相似文献
179.
Christopher A. Pocknee Sarah M. Legge Jane McDonald Diana O. Fisher 《Conservation biology》2023,37(4):e14062
Fire has shaped ecological communities worldwide for millennia, but impacts of fire on individual species are often poorly understood. We performed a meta-analysis to predict which traits, habitat, or study variables and fire characteristics affect how mammal species respond to fire. We modeled effect sizes of measures of population abundance or occupancy as a function of various combinations of these traits and variables with phylogenetic least squares regression. Nine of 115 modeled species (7.83%) returned statistically significant effect sizes, suggesting most mammals are resilient to fire. The top-ranked model predicted a negative impact of fire on species with lower reproductive rates, regardless of fire type (estimate = –0.68), a positive impact of burrowing in prescribed fires (estimate = 1.46) but not wildfires, and a positive impact of average fire return interval for wildfires (estimate = 0.93) but not prescribed fires. If a species’ International Union for Conservation of Nature Red List assessment includes fire as a known or possible threat, the species was predicted to respond negatively to wildfire relative to prescribed fire (estimate = –2.84). These findings provide evidence of experts’ abilities to predict whether fire is a threat to a mammal species and the ability of managers to meet the needs of fire-threatened species through prescribed fire. Where empirical data are lacking, our methods provide a basis for predicting mammal responses to fire and thus can guide conservation actions or interventions in species or communities. 相似文献
180.
Cynthia D. Fisher 《组织行为杂志》1998,19(5):503-522
It is proposed that attentional difficulties are central to the experience of boredom. Events which disrupt attention during task performance may contribute to feelings of boredom with the task. Two sources of disruption are explored: external interruptions from the physical environment, and internal interruptions in the form of non-task-related thoughts about current concerns. Study 1 found that external interruptions reduced boredom on a simple task which required little attention, but contrary to expectations, had no impact on reactions to a simple task that did require attention or on reactions to a complex task. Study 2 manipulated internal interruptions via a role-playing methodology, and found that observers attributed greater boredom and less satisfaction to performers who were more frequently interrupted by non-task-related thoughts while at work, especially when these thoughts were about non-urgent concerns. The concepts of internal and external interruptions may be quite useful in understanding variations in the day-to-day experience of work, and in the relationship of non-work to work spheres of life. © 1998 John Wiley & Sons, Ltd. 相似文献