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Ecology and restoration techniques for Sargassum beds in the Seto Inland Sea, Japan.

Due to the reduction and degradation of coastal areas in Japan by land reclamation and anthropogenic perturbations, from the point of view of conservation of the coastal environment, the restoration of Sargassum beds is essential. Between 1978 and 1991, 6400 ha of seagrass and seaweed beds have been lost along the Japanese coast, of which Sargassum beds were 22%. New techniques for Sargassum bed restoration are summarized based on three coastal engineering techniques. (1) Construction of shallow and gentle sloping bottom substrata have been shown to be effective for the reestablishment of 'management-free seagrass and Sargassum beds' on developed coasts. (2) Seeding or transplanting using artificial substratum for extension of nursery and fishing grounds around natural Sargassum beds. (3) Periodic transplanting of Sargassum plants using artificially produced seedlings is effective to produce niches to allow faunal re-colonization in severely polluted and sparsely vegetated area. However, prior to implementation, the suitability and limitations of these three techniques requires to be ascertained for effective Sargassum bed restoration.

Aquaculture↗

Approaches to environmental restoration of a polluted harbour with submerged archaeology: the Alexandria case study.

Many invaluable underwater buildings of archaeological interest in Alexandria were discovered in 1996 at different sites in the Eastern Harbour of Alexandria. There is a belief that the best way to protect these invaluable heritages is to transfer them to an underwater park or museum. Obviously, the execution of such a project depends essentially upon the water quality (including water transparency) improving in the future. The harbour is presently polluted by discharge of wastewater effluents from different sources. It has recently been decided to restore this important coastal area through: (1) stopping the direct discharge of wastewater effluents into this semi-enclosed harbour in 1993 and (2) gradually reducing the discharge of the municipal wastewater through marine outfalls at two sites lying at the outer sides of the harbour. Zero discharge is expected to be effective by the end of the year 2001. The present work, therefore, is a follow up of the study of water quality in the harbour after 1993: in 1996 and 1999-2000. The water quality of an open sea reference station was also studied for comparison. The results reveal occurrence of an improvement of the environmental conditions in the harbour. The water has turned from being eutrophic to mesotrophic. The harbour is expected to become meso/oligotrophic as soon as the complete cessation of the discharge from the two outside sources is attained.

Archaeology↗

Rodent navigation after dissociation of the allocentric and idiothetic representations of space.

Analysis of the neural mechanisms of place navigation requires isolation of the landmark dependent allocentric and self-motion related idiothetic orientation modes. To assess their importance, rats were trained on a rotating (360 degrees/min) arena to avoid foot shocks applied in either a room frame defined sector of the arena or an idiothetically defined region of the floor. Independence of the respective allocentric and idiothetic engrams was revealed by simultaneous avoidance of both locations. The possibility that idiothetic orientation was confounded by allocentric intramaze cues was examined in an apparatus consisting of an inner rotating disc surrounded by a stationary belt. As long as the rat was on the moving disc, position of the 60 degrees shock sector was stable on the disk but projected from it to different parts of the belt. When the rat moved to the belt the shock sector was now stable on the belt, but its projection to the disk travelled over its moving surface. The rat always found the shock sector in an idiothetically correct position but the mutual shifts of the disk and belt eliminated the utility of local cues like scent marks for the idiothetic solution of the task. Purely allocentric orientation was required in a place recognition task in which pressing a lever mounted on a rotating arena was rewarded only when the operandum moved through an allocentrically defined 60 degrees segment of its trajectory. Place recognition was manifest by increased bar pressing rates on approach to and inside the reward zone. These methods may reveal how hippocampal place cell activity correlates with both allocentric and idiothetic aspects of spatial orientation.

Animals↗

Learning of landmark stability and instability by hippocampal place cells.

Place cells in the rat hippocampus fire whenever the animal is in a particular location. In a symmetrical environment, their receptive fields (place fields) are oriented by visual cues, and if these are unavailable they are oriented by movement-generated (idiothetic) cues. The present study tested the hypothesis that the cells would learn not to 'trust' a visual cue if the rat experienced it to be unstable (Knierim et al., 1995. Place cells, head direction cells and the learning of landmark stability. J. Neurosci. 15, 1648-1659). In an otherwise symmetrical environment, a visual cue was moved with respect to the idiothetic cues, either in sight or out-of-sight of the rat. When the visual cue was moved out-of-sight of the rat, place fields were initially oriented by this cue in preference to the idiothetic cues. However, if the cue was seen by the rat to be mobile, place fields ceased following the visual cue and became oriented by the idiothetic cues instead. If the cue was not seen to be mobile until the rat had had several days of experience in the environment, then the fields continued to be oriented by the (now visibly mobile) visual cue. It thus appears that the orienting influence of a visual cue on place fields can be either strengthened or weakened relative to the idiothetic cues, depending on the experience of the rat.

Animals↗

Practical environmental modifications for the inhalant allergy patient.

Environmental management of inhalant allergens is an important part of a comprehensive allergy management program and is the most controllable aspect by the patient. The safest and most effective way to eliminate an allergic reaction is to eliminate exposure to the antigen that provokes the response. The basic control principles for all inhalant allergens are to (1) remove the source of the allergen if possible, (2) remove accumulated allergen, and (3) prevent the return of the allergen. This article examines the published evidence for environmental control measures in terms of effectiveness, cost, and ease of implementation.

Air Pollutants↗

Temporal variability of preferred lighting conditions self-selected by women.

The purpose of this study was to know what quantity and quality of illuminance during the waking period is selected by subjects and to discuss these in terms of circadian rhythm of core temperature. Five females served as subjects. They were instructed to choose the intensity and color temperature of the illumination they preferred every 15 min during wakefulness by adjusting a light box. The illuminance selected rose during the course of the first 5 h and the color temperature rose over the first 2 h that they waked. Both parameters were decreased steadily over the 5 h before retiring. When the chosen illuminances and color temperatures were plotted against core temperatures during these two periods, it was found that both of these parameters were higher for identical core temperature in the morning after rising than in the evening before retiring. This behavior could accelerate the morning rise of core temperature (at the time when the set point is rising) and the fall of core temperature in the evening (at the time when the set point is falling).

Adult↗

Meal patterns of lean and leptin-deficient obese mice in a simulated foraging environment.

C57BL/6J lean and obese (lep -/-) mice were studied in a closed economy operant protocol that simulates foraging. A predetermined number of presses on a procurement lever (PFR) activated a consumatory lever on which presses would produce 20-mg food pellets. Mice could eat as much as they wished but, once no responding occurred for an elapsed 10-min period, the consumatory lever was inactivated and the procurement or foraging cycle began again. Under these conditions, as has been shown for rats and other species, mice initiated relatively discrete meals (about nine per day) at the lowest PFR, and the number of meals initiated per day decreased with increasing PFR. Meal size increased reciprocally, so that total intake was conserved across the range of PFR examined. Obese mice ate larger meals than lean mice at low PFR, and showed further increases but only at the highest PFRs. The small and inconsistent literature on meal patterns in mice is reviewed, and we discuss the utility of the present protocol to study the interactions between genetic and environmental economic factors, and their implications for the etiology of human obesity.

Animals↗

Kinetics of chemical decolorization of the azo dye C.I. Reactive Orange 96 by sulfide.

The mechanism of decolorization of azo dyes based on the extracellular chemical reduction with sulfide (H2S, HS-, S2-) was postulated for sulfate reducing environments. To design technical decolorization processes of textile wastewater treatment with sulfide produced by sulfate reducing bacteria (SRB), kinetics is of great significance. Batch experiments were made in order to investigate the kinetics of abiotic decolorization of the reactive mono-azo dye C.I. Reactive Orange 96 (RO 96) with sulfide, with varying pH. The decolorization of RO 96 by sulfide under the exclusion of O2 corresponded to first-order kinetics with respect to both dye and sulfide concentration. The decolorization of RO 96 with sulfide at neutral pH (7.1) was advantageous compared with that at pH for 4.1, 6.3, and 6.5. This is attributed to an increase in the fraction of HS- of total sulfide species at neutral pH. The rate constants k for the decolorization at 37 degrees C were obtained as 0.01 for pH = 4.1, 0.06 for pH = 6.3, 0.08 for pH = 6.5, and 0.09 for pH = 7.1 in mM(-1) min(-1). The high rate constants for sulfide at pH 6.5-7.1 support that the decolorization through SRB (i.e. by bio-sulfide) can be effective in anaerobic bacterial systems with sulfate.

Azo Compounds↗

Phytoremediation of selenium by two helophyte species in subsurface flow constructed wetland.

The phytoremediation of selenium by two different wetland species was investigated. Selenium (20.4 microg/l) was supplied continuously to subsurface flow constructed wetlands, one vegetated with Typha latifolia L. and the other with Phragmites australis (Cav.) Trin. ex Steud. The beds of both species had same hydraulic loading rate (0.079 m(3)/m(2)/d) and water retention time (24 h). However, the mass loading rate was 1.27 mg Se/m(2)/d for Phragmites and 1.35 mg Se/m(2)/d for Typha. In the Typha bed Se migrated faster than in the Phragmites bed. After 25 d of Se supplementation in the Typha bed about 54% of the Se inlet concentration remained in the outlet water. In the Phragmites bed Se was removed completely from the water after passing through 3/4 of the bed length. After 65 d of Se supplementation the highest amount of Se (2.8 microg/g dry matter) was determined in the organic material of the Typha bed. Roots and rhizomes accumulated 2.2 and 1.8 microg/g dry matter respectively. Phragmites accumulated Se in the leaves and stems, but not in the rhizomes. The accumulation in the leaves (1.8 microg Se/g dry matter) was three times higher than in the stems (0.6 microg Se/g dry matter).

Biodegradation, Environmental↗

Analysis of the recent storm record in the southwestern Spanish coast: implications for littoral management.

This work compares the geomorphologic evolution of the Huelva coast (SW Spain), some climatic-oceanographic data of the Cádiz Gulf and the recent storm record of this zone, covering the last 4 decades (1956-1996). An interesting correlation was found between the southwestern wind periodicity, the number of storm periods and the beach ridges observed in the main spits (El Rompido and Doñana). The spectral analysis of the wind time series permits to establish two most probable levels of periodicity: 6 and 9-10 years. Both periods coincide with the storm record and the creation of new beach ridges after a high-energy period. Beach damage, another storm-induced effect, was analysed by deducing different implications for the future management of tourist localities.

Disasters↗

Industrial surface impoundments: environmental settings, release and exposure potential and risk characterization.

This paper presents the results of a national scale evaluation of the environmental impact of surface impoundments that contain non-hazardous wastewaters. In the 1990s, it was found that approximately 18,000 surface impoundments existed in the US for treating, storing or disposing of non-hazardous wastewater. In this study, the focus was on the subset of 11,900 impoundments that contain at least one of 256 chemicals of interest or high or low pH wastewater. Questionnaires were sent to facilities chosen in a two-phase nationally representative random sample. The nature, extent and use of surface impoundments across manufacturing industries were characterized using the information collected in the survey. Also, the chemical composition of impounded wastewaters; the potential for chemical releases to the environment from the impoundments; and the risk from these releases were assessed. It is estimated that only approximately 5-6% of facilities with impoundments have the potential to pose risks to human health, although approximately 19-46% of facilities with impoundments release chemicals of concern to the environment. The information in this study should help environmental managers evaluate and avoid those risk factors that have the potential to result in environmental harm, particularly when present in combination.

Environment Design↗

The future of human spaceflight.

After the Apollo Moon program, the international space station represents a further milestone of humankind in space, International follow-on programs like a manned return to the Moon and a first manned Mars Mission can be considered as the next logical step. More and more attention is also paid to the topic of future space tourism in Earth orbit, which is currently under investigation in the USA, Japan and Europe due to its multibillion dollar market potential and high acceptance in society. The wide variety of experience, gained within the space station program, should be used in order to achieve time and cost savings for future manned programs. Different strategies and roadmaps are investigated for space tourism and human missions to the Moon and Mars, based on a comprehensive systems analysis approach. By using DLR's software tool FAST (Fast Assessment of Space Technologies), different scenarios will be defined, optimised and finally evaluated with respect to mission architecture, required technologies, total costs and program duration. This includes trajectory analysis, spacecraft design on subsystem level, operations and life cycle cost analysis. For space tourism, an expected evolutionary roadmap will be described which is initiated by short suborbital tourism and ends with visionary designs like the Space Hotel Berlin and the Space Hotel Europe concept. Furthermore the potential space tourism market, its economic meaning as well as the expected range of the costs of a space ticket (e.g. $50,000 for a suborbital flight) will be analysed and quantified. For human missions to the Moon and Mars, an international 20 year program for the first decades of the next millennium is proposed, which requires about $2.5 Billion per year for a manned return to the Moon program and about $2.6 Billion per year for the first 3 manned Mars missions. This is about the annual budget, which is currently spend by the USA only for the operations of its Space Shuttle fleet which generally proofs the affordability of such ambitious programs after the build-up of the International Space Station, when corresponding budget might become again available.

Equipment Design↗

Geomorphological evolution and environmental reclamation of Fusaro Lagoon (Campania Province, southern Italy).

Analysis of morphological, geological and environmental characteristics of the Fusaro Lagoon has shown the present degraded condition of the lagoon and the perilagoon area. The lagoon developed during the mid-Holocene within a wide marine bay confined between the coastal volcanic structures of Mt. Cuma to the north and Torregaveta to the south in the western part of the Phlegrean Fields. Subsequently, the bay was gradually filled with pyroclastic materials from phlegrean eruptive vents and sediments carried by the rivers Volturno and Clanis, thus, creating an open lagoon. It then evolved into a partially closed lagoon due to the formation of a continuous littoral spit during the late Holocene, probably wider than the present-day one and surrounded by marshlands. Finally, the total closure of the lagoon took place in the Graeco-Roman period, following the stabilization of the dune ridge, and it assumed a shape similar to present-day one only towards the end of the 18th century. Between the Roman period and 1941, three lagoon channels were opened in order to avoid the frequent environmental crises which continue to affect, although for different reasons, this salt-water basin. The basin has been exploited for more than 2000 years not only for mollusc culture and pisciculture, but also for the maceration of hemp and flax. In the 1980s, in order to reduce the effects of the environmental crises, dredging of the lagoon bottom has been carried out, altering the hydrogeological equilibrium and that of the ecosystem. Over the past 30 years, the supply of raw sewage of domestic, agricultural and industrial origin has ensured the presence of a high concentration of pollutants, including heavy metals. On the basis of the data obtained and in order to restore this sensitive transitional environment, eco-compatible interventions are proposed which aim at morphological and hydrologic resettlement, abatement of pollutants on the bottom of the basin, reintroduction of endemic molluscs, together with monitoring the quality of sediments and both sea-lagoon waters and groundwater.

Agriculture↗

Reform in the garden.

English gardens powered by steam engines offer an intriguing view of how technological and scientific progress was naturalized in the landscape of 19th-century Prussia, and in Prussian culture, during the early years of industrial modernization. One such garden is Peacock Island, in the Havel River near Potsdam. A product of the reform era that preceded and followed the Napoleonic Wars, it expressed the goal of Friedrich Wilhelm III and his government to enter into the British system of factory production and world trade. Modern science, as represented especially by Alexander von Humboldt, played a prominent role.

Botany↗

Paw withdrawal threshold in the von Frey hair test is influenced by the surface on which the rat stands.

The effect of testing surface on the rat hind paw withdrawal threshold in the von Frey hair test is investigated in this study. The data indicate that wire mesh, which is typically used to apply von Frey hairs, may have an effect on the paw withdrawal threshold. For example, in control rats tested on the wire mesh, variability in the withdrawal threshold was observed between the left and the right hind paws (51.04+/-12.29 and 64.31+/-9.37 g, respectively) and on different days of testing (35.24+/-9.54 and 45.83+/-12.97 g for the left and right hind paws, respectively, 7 days later). In an attempt to reduce this variability, a customized platform was used to measure the von Frey hair-induced paw withdrawal in the rat. It consists of an opaque, flat-surfaced plastic platform with holes through which von Frey hairs are inserted and applied to the plantar surface of the paw. In control rats tested with von Frey hairs using this customized platform, variability in the paw withdrawal thresholds between the left and right hind paws in single rats over time as well as between different rats was reduced (49.86+/-6.97 and 49.29+/-6.56 g for the left and right hind paws, respectively, on day 0; 48.29+/-5.82 and 53.00+/-4.59 g for the left and right hind paws, respectively, 7 days later). Furthermore, in rats in which a 2 mm polyethylene cuff was used to constrict the left common sciatic nerve, the ipsilateral as well as the contralateral hind paw withdrawal thresholds were decreased (2.45+/-0.65 and 26.09+/-5.86 g, respectively, 7 days later). In similar rats tested on the wire mesh, the ipsilateral but not the contralateral paw withdrawal threshold decreased (12.80+/-2.21 and 65.00+/-10.28 g, respectively, at 7 days). The data suggest that the flat surface and opaque properties of the customized platform enable accurate, reliable and repeatable measurements of ipsilateral and contralateral paw withdrawal threshold using von Frey hairs in normal and nerve-injured rats.

Animals↗