bluuebunny/crossref_metadata_2025 huggingface dataset:
Species richness of microcrustacea in subterranean freshwater habitats. Comparative analysis and approximate evaluation
Authors: Rouch Raymond , Danielopol Dan L.
Published: February 2007

Among terrestrial biomes the groundwater domain is generally considered to be a species poor environment. This view results, mainly, from the large geographic scale faunistic surveys (tens and hundreds of kilometres) and the traditionally coarse spatial scale (i.e. macroscale level) of ecological analysis. This view has been challenged by Margalef (1993) who suggests that high diversities are to be expected in the subterranean environment comparable to those found in the deep sea because of environmental similarities, e.g. low energetic resources.

During the last twenty years long‐term ecological research on much smaller scales, i.e. metres to hundred metres for interstitial media, a mesoscale approach, or kilometre size for karst systems was carried on. Long‐term projects on limnic subsurface systems have shown that the species richness (SR) of the microcrustacea (Harpacticoida, Cyclopopoida, Ostracoda) is much higher than previously considered. Details on Harpacticoida of the alluvial bedsediments of a Pyreneean brook, the Lachein, and on Ostracoda of the alluvial sediments of the Danube plain (the phreatic zone), near Vienna, are presented. The SR values of the interstitial microcrustacea obtained through investigations at a mesoscale level are comparable to those of karstic and/or surface freshwater benthic water systems; they are lower than those of the deep‐sea data sets for equivalent crustacean groups at a similar scale of investigation.

From the data presented we infer the following points: (a) The subterranean waters are much more rich in species than earlier accepted, at least for some organismic groups like the microcrustacean copepods and ostracods. (b) Hence, to describe the still unknown fauna it is appropriate to sample the subsurface waters at an ecological scale. (c) Only studies during long‐term ecological projects and with intensive, quantitative, sampling programmes allow a correct evaluation of the subterranean faunal diversity. (d) The species richness of a given subsurface site is strongly dependent on the structure of the habitats and the functioning of the underlying ecosystems. (e) Finally we consider the rationale for the protection of the subterranean faunal diversity.
Occurrence of cyanobacterial blooms in the baltic sea in relation to environmental conditions
Authors: Wasmund Norbert
Published: February 2007

Cyanobacterial blooms occur regularly in summer in central parts of the Baltic Sea. They are mainly composed of Aphanizomenon sp. and Nodularia spumigena. Both species have almost similar ecological requirements and can roughly be considered a uniform functional group.

In order to identify factors that might favour bloom development, water quality data from monitoring programmes were compared with bloom distribution.

A salinity from 3.8 to 11.5 PSU proved important for the spatial distribution of the bloom development. The bloom's onset was triggered by temperatures approximating 16°C provided that global radiation was > 120 W/m2 (daily mean) and wind speed was < 6 m/s. Nutrient concentrations decreased immediately before the bloom.

The bloom's development ceased with poor weather conditions characterized by low irradiation or high wind speed.
The genus Thermocyclops (Crustacea: Copepoda) in Uzbekistan (Central Asia)
Authors: Mirabdullayev Iskandar M. , Kuzmetov Abdulahmed R.
Published: February 2007

Five Thermocyclops species were found in Uzbekistan: T. crassus, T. dybowskii, T. rylovi, T. taihokuensis, and T. vermifer. The last species has been for the first time recorded in the region. The data on morphology, variability and distribution of these species in Uzbekistan are given. A key to determine to the five species is proposed.
Trace metal bioaccumulation in soft‐bottom macrobenthos from the San Pedro Shelf, California
Authors: Maurer Don , Gerlinger Thomas , Robertson George , Nguyen Hai
Published: February 2007

The relationship between sediment trace metals (Ag, Cd, Cr, Cu, Ni, Pb, Zn) and bioaccumulation in tissue of macrobenthos (Parvilucina tenuisculpta, Tellina spp., Macoma spp., Pectinaria californiensis, Nephtys spp., Glycera spp., Metasychis sp., Euphilomedes spp., and Ampelisca spp.) was described from 1975 to 1985 on the San Pedro Shelf, California. Results indicated that: 1) sediment trace metals were elevated at an ocean outfall station; 2) tissue trace metals were never statistically higher at the outfall compared to a reference station except for Zn in Macoma spp.; 3) there were a few statistically significant associations (r) between tissue and sediment metals, but no consistent trends emerged; 4) peak tissue metal concentrations occurred more frequently in the winter than in the summer.
Light adaptation of the phytoplankton diatom Phaeodactylum tricornutum under conditions of natural light climate
Authors: Müller Anna‐Maria , Wilhelm Christian
Published: February 2007

Cells of Phaeodactylum tricornutum were precultured under axenic conditions in a full medium and then exposed to natural light conditions at various depths in the eutrophic lake „Meerfelder Maar”︁ (Eifel, FRG) for several days. After exposition the cells were characterized with respect to growth parameters, photosynthetic performance and xanthophyll cycle pigments. In order to test the resistance of the cells grown at different depths against photostress, the cells were illuminated with photoinhibitory light. The variable chlorophyll a‐fluorescence and the oxygen quantum yield at a non‐saturating light intensity were simultaneously measured after photostress and subsequent recovery. The xanthophyll cycle pigments and the content in α‐tocopherol were monitored during photostress to get molecular information about the physiological reasons of light‐stress resistance. The data give evidence that cells grown close to the surface show a faster decline in photosynthetic performance and a more efficient recovery than cells from lower depths. There is clear indication that under natural conditions when the light is fluctuating between optimal, sub‐ and supraoptimal intensities the photostress resistance is much higher than under conditions of the absence of light stress. The molecular basis for light stress resistance seems to be the pool size and the conversion kinetics of the xanthophyll cycle pigments and the capacity of the oxygen‐scavenging system. The effect of in‐situ light adaptation is discussed with respect to the assessment of the potential of the primary production.
Demography of a population of Moina micrura kurz (Crustacea: Cladocera) in a temporary pond, peninsula of paraguaná, Venezuela
Authors: López Carlos , Theis Solange
Published: February 2007

A population of M. micrura Kurz from a shallow, muddy and temporary pond, located in Peninsula of Paraguaná, western Venezuela, was studied from filling to drying phase. Population density, age structure, fecundity, and length of females, were determined. This population showed a low population density (< 50 ind/1), a low and density‐dependent fecundity (mean eggs/adults = 1.3; mean clutch size = 2.1 eggs + embryos), and low juveniles to adults ratio (0.71). No significant correlation was detected between mean clutch size and mean body length of ovigerous females. Our results suggest effects of food limitations, and fish predation on demographic parameters of this population. Still, in unfavourable conditions, some demographics features associated to opportunistic species were evident.
Longitudinal zonation and life cycles of macrozoobenthos in the Mauerbach near Vienna, Austria
Authors: Baumgartner A. , Waringer J. A.
Published: February 2007

A total of 12277 benthic invertebrates were caught from November 1990 to October 1991 at the Mauerbach, a first to fourth order forest brook near Vienna, Austria, using a Surber sampler and a hand net. Five taxa comprised 96.6% of the catch: Diptera larvae (45.6%), Amphipoda (37.6%) and larvae of Ephemeroptera (6.4%), Plecoptera (5.3%) and Trichoptera (1.7%).

Mean values of macrozoobenthos density ranged from 39514 specimens m−2 at upstream sampling site 5 in December to only 286 specimens m−2 at sampling site 3 in May, shortly after a severe flood.

Based on benthic invertebrate population structure, sites 5 and 6 (situated near the source) were clearly separated from the downstream sites 1 to 4. At upstream sites, shredders comprised up to 71.7% of the total, whereas at downstream sites collectors were most abundant. In addition, the proportion of eucrenal species decreased from 12% at site 6 near the source to only 2% at site 1 near the mouth.

Among the insect species studied in detail, most were univoltine except Ephemera danica (Ephemeroptera) and Sericostoma personatum (Trichoptera), which had a two‐year life cycle.
Additions to the Lecane fauna (Rotifera: Monogononta) of Thailand
Authors: Sanoamuang La‐Orsri , Segers Hendrik
Published: February 2007

Lecane superaculeata. n. sp. is described from three localities in Thailand. It resembles the small, cosmopolitan L. aculeata (Jakubski, 1912) but is distinguished by its larger size and conspicuous anterolateral spines. Additional records of some recently described Thai Lecane species and comments on Oriental endemics are presented L. eswari Dhanapathi is newly recorded for the country.
First Record of the Gobioid Fish Eleotriodes wardii Playfair (Pisces: Eleotridae), from the Central Indian Ocean
Authors: Venkateswarlu T. , Rao Kaza V. Rama
Published: February 2007

This species was previously reported only from its type locality (Zanzibar). In 1975 a specimen was collected near Madras at a depth of 15–25 m. A description of the species along with a drawing is provided.
Chemical Studies of Superficial Sediments in Lake Lilla Ullevifjärden
Authors: Ryding Sven‐Olof , Borg Hans
Published: February 2007

Many sampling stations are preferable in sediment investigations. With a basis of only single samples an unequivocal determination of the lake's sediment character is hard to obtain. Knowledge of the morphometrical conditions is an advantage, as in steeply sloping parts great changes in concentrations can occur. However, even unexpected distribution patterns can emerge and a map of horizontal distributions in sediments can never be looked upon as completely reliable. The traditional sediment picture (based on dry weight) with increasing concentrations of several elements with depth can often give a false impression of the distribution of amounts per volume wet sediment with maximum values in somewhat shallower parts which, from an ecological point of view, should be the important one.
The Chemical Composition of Four Regions on a Summer Day in Lake Lacawac, Pennsylvania
Authors: Cowgill U. M.
Published: February 2007

This paper is devoted to the varying concentrations of 49 elements found in the water from three littoral sites and one pelagic site, sampled over a five hour period, in Lake Lacawac. These elements were detected in concentrated water samples by use of X‐ray emission and optical emission spectroscopy. The elemental concentrations of the four sampling sites differed. Statistical analyses were used to estimate how chemical mixing proceeded in the surface waters of the lake. Results from a previous study of the chydorid Cladocera living in the sediments beneath the water sampling sites indicated that the more organic sediments contained more individuals than the sandy sediments. The chemical concentration of the water followed the same distribution as did the organisms.
Le Phytoplancton de l'Estuaire moyen du Saint Laurent en amont de l'Ile‐aux‐Coudres (Québec). The Phytoplankton of the Upper St. Lawrence Estuary (Québec)
Authors: Cardinal A. , Cardinal A. , Bérard‐Therriault L.
Published: February 2007

The authors give here a qualitative and quantitative description of the phytoplancton in the brackish waters of the St. Lawrence Upper Estuary (Québec). The very high observed concentrations are the responsibility of fresh‐water forms: Skeletonema subsalsum, Melosira binderana, Diatoma elongatum, Asterionella formosa, Fragilaria crotonensis, F. capucina, Cyclotella striata, Melosira islandica, Ankistrodesmus falcatus and Scenedesmus quadricauda; 193 species are listed in an appendix.
Effet de divers sels alcalins sur la croissance et la nutrition minérale de Lemna minor L
Authors: Strauss René
Published: February 2007

Lemna minor L. was grown in aseptic culture solutions. With sodium chloride or lithium chloride in the solution, the plant increased in yield. Tolerance of Lemna minor to relatively high level of sodium explains the presence of this plant in brackish waters. A low quantity of potassium is required for optimal growth.

Sodium was added to nutrient solutions as chloride or sulphate. At equivalent levels the sodium content of the plant was somewhat higher under sulphate salinity.
Survival of Mayfly Larvae Under Mine Acid Conditions
Authors: Napier Stanley , Hummon William D.
Published: February 2007

Mayfly larvae were abundant and diverse in riffle zones of three control streams in southeastern Ohio. But none were found in such zones of three streams having current or past histories of mine acid pollution, despite vegetative recovery of reclaimed land bordering two of the streams.

Laboratory studies showed stepwise increases in non‐predatory mortality of mayfly larvae with increased mine acidity. Dragonfly larvae predation on mayfly larvae was constant at pH 8.1–4.1, but decreased at pH 3.1 despite tolerance of dragonfly larvae to low pH conditions. Extensive acid mine pollution thus may threaten aquatic biota through removal of food sources or reduced feeding rates as well as through direct mortality.
Subsurface Chlorophyll Maximum and Associated Cyclotella Pulse in Lake Superior
Authors: Fahnenstiel Gary L. , Glime Janice
Published: February 2007

An investigation of the subsurface chlorophyll layer (SCL) in Lake Superior was conducted from 1 May through 15 October. During spring unstratified conditions (1 May–17 July), chlorophyll a and phytoplankton biomass were vertically and temporally uniform. Phytoflagellates such as Rhodomonas minuta, Cryptomonas spp., and Ochromonas spp. were dominant at this time. The photosynthetic maximum was associated with the depth receiving 10% of surface irradiance, ca. 15–25 m. Once thermal stratification occurred, a SCL developed around 20 m. Although epilimnetic chlorophyll concentrations remained similar to spring mixing levels, concentrations in the SCL increased 3‐fold. In situ production was the principal process associated with the development of the SCL. The upper portion of the SCL was dominated by Cyclotella species; C. stelligera, C. comensis, and C. ocellata. The increased abundance of Cyclotella appeared to be related to stable irradiance fields produced during thermal stratification.
Evaluation of Succession in an Estuarine Macrobenthic Soft‐Bottom Community near Tampa, Florida
Authors: Santos Stuart L. , Bloom Stephen A.
Published: February 2007

A subtidal macrobenthic infaunal community was quantitatively sampled monthly from February 1975 to July 1978 (42 months). During that period, complete defaunation (presumably due to hypoxia) occurred three times at approximately annual intervals. The recovery of the community was examined for successional patterns by quantitative and qualitative normal and inverse classification analyses and by rank‐order analysis of the dominant species. There was no consistent pattern of succession from recovery to recovery. Samples taken just after defaunation were not similar to each other and no consistent suites of species were detected. Classical succession in which suites of species are successively replaced by other suites until a persisting suite of species occurs (faciliation model) was not found. Other models of succession are discussed.
Trace Metal and PCB Content of Mussels (Mytilus edulis) from the Southwestern Baltic Sea
Authors: Möller Heino , Schneider Rolf , Schnier Christian
Published: February 2007

The concentrations of polychlorinated biphenyls and 28 metals were determined in mussels from 32 stations in the southwestern Baltic Sea. Elevated levels of PCBs (up to 28 mg/kg lipids) were found in harbour areas. Increased amounts of some metal contaminants were found in three large areas. The discharge from a sewage plant is responsible for high residues at stations in the outlet of Kiel Fjord. Increased levels of heavy metals in the outer Flensburg Fjord and in the vicinity of Fehmarn Sound seem to be due to natural geological formations, as indicated by the occurrence of elements that usually are not found at high concentrations in anthropogenic wastewaters.
A Comparative Study of Respiration Rates of Some Aquatic Oligochaetes in Relation to Sublethal Stress
Authors: Brinkhurst Ralph O. , Chapman Peter M. , Farrell Melody A.
Published: February 2007

Aquatic oligochaete species selected on the basis of pollution tolerance or intolerance as determined from field studies were used to determine respiration rates under standard conditions, after exposure to sublethal levels of environmental variables (pH, salinity, temperature) or toxicants (Cd, Hg, NaPCP) alone or in pairs. Respiration rates, critical oxygen levels and degree of regulation were not correlated with field‐determined tolerance to organic pollution. Stress factors caused increased or lowered respiration rate, loss of regulation (partial or total) and sometimes shifts in critical oxygen level. Regulation was improved in the face of some stresses. Combined stresses produced additional changes in respiration rates and regulation. These responses were complex, which makes them useful indicators of specific stress factors but also indicate complex mechanisms behind the observed changes.
Qualitative and Quantitative Entomofaunistic Investigation of an Opencast Residual Lake near Leipzig (GDR)
Authors: Jacob Udo , Klausnitzer Bernhard , Walther Hendrik
Published: February 2007

In the Kulkwitz opencast residual lake, which has existed since 1962 in the Leipzig lignite district (GDR), the physico‐chemical characteristics of water were recorded and qualitative and quantitative entomofaunistic inventories carried out. For the latter, a floating emergence trap was used, which caught a total of 8,397 insects above a water area of 2.25 m2 during the summer and autumn of 1979. These insects belong to 12 families and 4 orders. Dominances, diversities and equities were determined for the Trichoptera. The results were compared with those obtained in the acid Olba opencast residual lake northeast of Bautzen, which was investigated at the same time of year.
Responses of the Phytoplankton Community of a Tropical Reservoir (São Paulo, Brazil) to the Enrichment with Nitrate, Phosphate and EDTA
Authors: Henry Raoul , Tundisi José Galizia
Published: February 2007

The effects of artificial enrichment with nitrate, phosphate and EDTA on the phytoplankton community were studied in the Lobo Reservoir (São Paulo, Brazil). After 14 days of in situ incubation, the amounts of suspended matter and chlorophyll a, the numbers of cells and the carotene/chlorophyll ratio were determined. The addition of nitrate and phosphate to water samples produced significant effects on the chlorophyll a and cell counts, while EDTA acted only on the cell production. Both nitrate and phosphate, when analysed individually, caused a decrease in the value of the carotene/chlorophyll ratio. A synergistic effect of the addition of EDTA and N on the suspended matter was observed.
Assessment of δ13C and C/N ratios in bulk organic matter as palaeosalinity indicators in Holocene and Lateglacial isolation basin sediments, northwest Scotland
Authors: Mackie Elizabeth A. V. , Lloyd Jeremy M. , Leng Melanie J. , Bentley Michael J. , Arrowsmith Carol
Published: February 2007

Carbon isotopes (δ13C) and C/N ratios from bulk organic matter have recently been used as alternative proxies for relative sea‐level (RSL) reconstruction where there are problems associated with conventional biological indictors. A previous study on a single isolation basin (Upper Loch nan Eala) in northwest Scotland has shown a clear relationship between δ13C, C/N ratios and palaeosalinity from Younger Dryas and Holocene aged sediments. In this paper we present results of δ13C and C/N ratio analyses from other isolation basins in northwest Scotland over the Holocene and the Lateglacial period in order to validate this technique. The results from the Holocene sequences support the earlier findings that this technique can be used to identify RSL change from isolation basins over the Holocene in this region. The relationship between δ13C, C/N ratios and RSL change is not apparent in sediments of Lateglacial age. Other environmental variables such as atmospheric CO2 concentration, poor vegetation development and temperature influence δ13C values during this period. Copyright © 2007 John Wiley & Sons, Ltd.
Monitoring derelict urban land: A review of problems and potentials of remote sensing techniques
Authors: Kivell P. T. , Parsons A. J. , Dawson B. R. P.
Published: February 2007

The accelerating rate of change in urban areas calls for more rapid and cost‐effective surveys of derelict land. A review of the use of remote sensing1 for this task reveals that, although aerial photography has been used for urban analysis since the 1940s, it has not been widely adopted for surveys of derelict land, despite demonstrations of its utility. Other forms of remote sensing are similarly shown to have been little‐used and to have had patchy success. The hitherto restricted utility of remote sensing is found to be due to a combination of limitations of the forms of imagery available and the methods of analysis employed. Recent changes in available remote sensing imagery, notably the higher resolution now provided by the SPOT satellite, coupled with advances in digital image‐processing techniques point to improved opportunities for using remote sensing to monitor derelict land. As a demonstration of these developments, a texture image based on scene variance is derived from a SPOT image of part of north Staffordshire. All derelict and neglected land parcels larger than 1.25 ha are delimited on this image. Remote sensing techniques are not yet ready to supplant detailed ground surveys but they have a growing role to play in monitoring various aspects of land dereliction.
Transport processes for chernobyl‐labelled sediments: Preliminary evidence from upland mid‐wales
Authors: Bonnett P. J. P. , Leeks G. J. L. , Cambray R. S.
Published: February 2007

The nuclear accident at Chernobyl in April 1986 resulted in a significant increase in the inventory of radiocaesium retained in the soil in many regions of the United Kingdom. The deposition of 134Cs provides a convenient tool for the examination of erosional processes in upland systems. Detailed soil sampling has been undertaken within the Plynlimon experimental catchments to establish the pattern of deposition of Chernobyl‐derived radionuclides. The preliminary results of a combined radiometric and mineral magnetic approach to the study of the transport of Chernobyl‐labelled sediments and their source areas on these upland catchments in mid‐Wales are described.
Long‐term consequences of topsoil mining on select biological and physical characteristics of two New Zealand loessial soils under grazed pasture
Authors: Hart P. B. S. , August J. A. , West A. W.
Published: February 2007

Soil chemical, biochemical, biological and structural properties were measured in two New Zealand loessial soils that were topsoil‐mined 10 and 25 years ago respectively. Measurements at the 10‐year site were compared to some earlier measurements made at this site and the data combined in a chronological sequence for analysis. Topsoil mining had a large, detrimental impact on the soil microbial biomass, the earthworm populations, easily mineralizable N and soil enzyme activities. However, most of these properties substantially recovered, to 80‐90 per cent of the levels in unmined soils, within 10‐25 years of restoration under pasture. In contrast, while total soil C and N were less affected by topsoil mining, their recovery was much slower. Stabilities of macro‐aggregates of soil had fully recovered within 10‐25 years after topsoil mining. The apparent changes in all the measured properties between 10 and 25 years of restoration were small in comparison with changes between 0‐10 years of restoration after topsoil mining. The total C content of both soils under pasture appeared unlikely to attain the levels present in unmined soils. In soils undergoing restoration, the ratio of microbial C/total soil C may be a useful index of soil ‘biological stability’. Sulphatase activity may reflect the recovery of pasture production.
Small farm production in dominica, West Indies: A strategy for survival
Authors: Reading A. J. , Soussan J.
Published: February 2007

Calls for sustainable development have emerged largely because of the failure of technology‐focused, production‐orientated development policies to address the acute rural poverty and deteriorating environments of much of the Third World. Increased agricultural production through greater commercialization has a mirror image of decreasing incomes for the rural poor as market penetration undermines the viability of traditional production systems. These production systems are geared to minimizing risk through the harnessing of the full range of local resources, both private and communal, to produce goods for both the market and home consumption. The need for policies which strengthen traditional production systems is argued through a detailed case study of Dominica, in the Caribbean. The complexity and diversity of what is often considered a single‐crop (bananas) agricultural system is demonstrated by looking at a number of localities in different parts of the Island. The example of Dominica is used to argue for policies which, in the words of Robert Chambers, (1983), … ‘put the last first’. Such policies should strengthen existing diversity in the agricultural system through initiatives which give local farmers greater control over the planning and implementation of interventions. The sophistication of local technical knowledge is stressed, as is the need to integrate this knowledge with the technical expertise of outside professionals.
Dam construction and the degradation of floodplain forest on the Turkwel River, Kenya
Authors: Adams W. M.
Published: February 2007

A hydroelectric dam currently under construction is likely to have significant adverse impacts on riparian forest bordering the Turkwel River in northern Kenya. The forest is dominated by Acacia tortilis which depends upon river flooding. The River has a seasonal and highly ‘flashy’ flow regime, and floods are vital to recharge the floodplain aquifer. Flood regime, bruchid beetle infestation of Acacia pods, and the role of domestic herbivores in killing beetle larvae and grazing seedlings are important influences on Acacia regeneration. The riparian forest is a vital element in the grazing ecology of Turkana pastoralists, particularly in the dry season and in times of drought. Dam construction threatens the degradation of the forest both through reduced survival of existing trees and reduced regeneration. Such degradation would have serious implications for the Turkana.
Spatial and temporal dynamics of land degradation and fluvial erosion in the middle and upper Yangtze River Basin, China
Authors: Hengyue Gu , Douglas Ian
Published: February 2007

Land degradation in the middle and upper Yangtze has caused loss of cultivable land, sediment deposition in reservoirs and changes in the runoff: sediment yield relationships of major tributaries. The Jialin River and the Dukou‐Pingshan sector of the Jingsha River together contribute over 75 per cent of all the sediment carried by the Yangtze at Yichang. As the Jialin catchment has the highest rates of erosion per unit area, high sediment discharges from that river exert a major influence on peak summer sediment discharges on the Yangtze. Even though land degradation is increasing in severity, there is no clear overall pattern or trend in variations in sediment yield since 1950. Some tributaries are affected by major reservoir construction and soil conservation works, others are not.
Development of a microbiological treatment for restoration of oil contaminated soil
Authors: Bewley R. J. F. , Ellis B. , Rees J. F.
Published: February 2007

This paper describes the laboratory development of a microbial treatment for soil contaminated with oil hydrocarbon residues at a disused refinery site and the application of this technology in a pilot scale treatment bed in the field.

Micro‐organisms isolated from the site capable of utilizing a number of normal and branched chain alkanes were tested in a series of soil microcosms, together with various permutations of commercially available surfactants and nutrients for stimulating the activities of hydrocarbon‐utilizing micro‐organisms. Amongst the most effective reagents were: a the fertiliser ‘PurisolR’ 110(11 per cent N, 11 per cent P205, 11 per cent K20, ‘Chafer, Brit. Ag,’ Ltd.), which in combination with other supplements resulted in reductions of total oil hydrocarbons and associated polar products (TOHP) from 24,100 to below 16,000 mg kg−1 after five weeks (compared to 21,200 mg kg−1 in the control); (b) a hexadecane degrading Acinetobacter sp., which in combination with nutrients, reduced TOHP from 21,400 to 13,200 mg kg−1, in seven weeks compared to 16,800 mg kg−1 in the control and 15,100 mg kg−1 in the treatment with nutrients only and; (c) brewer's yeast which in combination with other supplements reduced TOHP from 16,300 to 7,600 mg kg−1 in 14 weeks.

These reagents, together with other supplements were applied to a pilot‐scale treatment bed consisting of 200 m3 of contaminated soil. Reductions in TOHP from 25,500 to 9,400 mg kg−1 were achieved in 15 months. Corresponding reductions in total oil hydrocarbons (TOH) from 22,600 to 2,000 mg kg−1 were achieved in the same period. After this time little further degradation was observed. The requirements for: (a) a critical evaluation of analytical methodology for assessing the bioremediation of oil contaminated soil, and; (b) considering the overall chemical stability of the asphaltene‐like residue remaining after biodegradation of the primary oil has taken place when setting meaningful targets for restoration of oil‐contaminated land, are highlighted in this study.
Reclaiming sandplain seeps by intercepting perched groundwater with eucalypts
Authors: George R. J.
Published: February 2007

At a sandplain seep at East Belka in the Western Australian Wheatbelt, saline groundwater discharge occurs from a shallow (approx. 2 m) perched aquifer of moderate permeability (0.15 m day−1). Groundwater qualities range from over 2,500 mS m−1 in the saline area, to between 660 and 1,700 mS m−1 in the plantation. In 1986 five varieties of eucalypts (E. globulus, E. cladocalyx var. nana and three provenances of E. camaldulensis) were planted across the contour upslope from the seep on about 1.0 per cent of the catchment. By 1989 the seedlings had grown to heights of up to 6.5 m. Despite above‐average rainfall over the study period, perched water‐tables under the plantation and seep were progressively lowered (approx. 0.5‐1.0 m) until the area was dry at the start of the 1989‐1990 summer. Wheat (Triticum aestivum) established on the seep and adjacent paddock in May 1989, provided a yield of over 1.0 t ha−1 on a site that had been unproductive for 20 years.

The method has the potential to reclaim much of the existing eastern and northern wheatbelt where there are salinity problems caused by perched groundwater, and could prevent recharge of the regional aquifer beneath the sandplain seep. However, additional techniques will be required to prevent deep aquifer discharge caused by steadily rising (approx. 0.15 m yr−1) regional water‐tables. Discharge and associated dryland salinity from the regional system are expected to be major problems during the next 40 years at the site investigated.
Field evaluation of relationships between a vegetation structural parameter and sheltering against wind erosion
Authors: Musick H. B. , Gillette D. A.
Published: February 2007

Measurements of natural vegetation canopies and of threshold friction velocities for soil movement were made at three arid and semiarid field sites. Threshold friction velocities for the vegetated surface and for bare soil were used to evaluate the partitioning of shear stress between that absorbed by the plant canopies and that absorbed by the soil surface (this potentially causing movement of soil particles). Canopy measurements were used to estimate lateral cover (total frontal‐silhouette area per unit ground area), a parameter shown by previous laboratory studies to be a good predictor of shear stress partitioning. The relationship between lateral cover and shear stress partitioning for the field sites agreed with the laboratory results of Gillette and Stockton (1989). Results indicate that the protective influence of vegetative cover against wind erosion can be successfully predicted using simple measurements of vegetation canopy structure.
Compaction of virgin soil by mechanized agriculture in a semiarid environment
Authors: Holloway R. E. , Dexter A. R.
Published: February 2007

Soil compaction was assessed in terms of soil strength as measured with a penetrometer. Penetrometer resistance was measured on virgin soil and on the same soil after one and after five passes of a 7,610 kg tractor. Also, comparative studies were made of strength profiles of soils in arable fields and in adjacent areas of virgin soil. The strength of virgin soil was increased by wheel traffic and agricultural operations in all cases. The increase in soil strength was significant down to 0.3 m, which is considerably greater than the normal depth of tillage in the area (0.05 m). Reduction in the coefficient of variation of penetrometer strengths after the passage of wheels was taken as evidence for associated losses of soil structure. Virgin soils provide important reference sites for assessing the impact of agriculture in an area.
The limits to growth debate and future crisis in Africa: A case‐study from Swaziland
Authors: Proctor J. D.
Published: February 2007

Although projections of future human and environmental crisis in subSaharan Africa caused by population growth beyond resource limits are common, they are often criticized due to their weak empirical or theoretical basis. This paper attempts to predict whether in 2000 AD there will be adequate cropland, grazing land and fuelwood reserves for a study area located in rural Swaziland. The objective was to establish the likelihood of future crisis, as well as to provide empirical evidence pertinent to the underlying theoretical debate about the relative significance of physical limits to growth. Data used for the study include past and recent aerial photography and census information, plus a field environmental assessment and household survey. Based on this information, projected year 2000 resource constraints for the study area range from minimal (in the case of fuelwood reserves) to extreme (in the case of livestock grazing areas). Other factors, however, such as unequal cropland allocation, household shortages of labour, and privatization of fuelwood supplies, have been found either to exacerbate these constraints or hinder rural resource utilization in the absence of significant physical constraints. A comparison of this study with the United Nations'Potential Population‐Supporting Capacities of Lands in the Developing World(see Higgins,et al., 1983) suggests that the UN projections, based on highly optimistic assumptions and little empirical evidence, are essentially meaningless. Although the results lend some support to the application of the limits to growth scenario to rural Swaziland, the classic ‘overshoot and collapse’ trend associated with that scenario is called into question. The results ultimately suggest that neither the Malthusian emphasis on physical constraints nor the Marxian emphasis on social and political constraints can be dismissed outright in research and policy related to future crisis in subSaharan Africa.
Nitrogen status and transformations in coal mine spoil
Authors: Shah S. S. H. , Flowers T. H. , Pulford I. D.
Published: February 2007

A detailed study was undertaken to measure mineral nitrogen status, mineralization rate of carbon and nitrogen, nitrification rate and fixation of added ammonium on 90 samples of coal mine spoils collected throughout Central Scotland. The inorganic nitrogen status of the spoils was very low (mean 3.4 mg N kg−1). The rate of carbon dioxide evolution was high compared to the low rate of nitrogen mineralized, resulting in a mean mineralized C:N ratio of 178. Nitrification of added ammonium was measurable on only half of the samples studied. Spoil with pH < 4.8 showed no nitrification of added ammonium. However, on some sites above this pH no net nitrification was measured, which suggested the absence of nitrifying bacteria. A considerable amount of applied ammonium nitrogen was lost either as a result of ammonium fixation by clay minerals, or assimilation by the heterotrophic population due to the wide mineralizable C:N ratio.
A comparison of soil degradation under smallholder farming and large‐scale irrigation land use in Kano State, Northern Nigeria
Authors: Essiet E. U.
Published: February 2007

Changes in soil properties under two land use types: smallholder farms and large‐scale irrigated agriculture were investigated over a period of 13 and 14 years respectively using the following parameters: particle size distribution, soil pH, exchangeable cations, cation exchange capacity, total organic carbon and nitrogen and total and available potassium and phosphorus. Results indicate that more adverse changes took place in soils under large‐scale irrigation than in those under smallholder farms during the periods under consideration. Agricultural sustainability is more likely to be achieved for smallholder farms than for large‐scale irrigation where soil degradation resulting from loss of fine soil particles through erosion can be a serious hindrance to long‐term land use. In order to achieve agricultural sustainability in Kano State, it is recommended that chemical fertilizers be incorporated into the smallholder farming system, while the adoption of suitable soil conservation practices would make the large‐scale irrigation systems more stable and sustainable.
Key factors affecting the initiation and progress of gullying in dambos in parts of Zimbabwe and Malawi
Authors: McFarlane M. J. , Whitlow R.
Published: February 2007

Accelerated gullying of dambos (seasonally waterlogged bottomlands) on commercial farms in Zimbabwe has resulted in legislation curtailing dambo cultivation, even in indigenous fanning areas. The transfer of indigenous cultivation to interfluve areas and the resultant concentration of cattle grazing in dambos initiated similar gullying. Facilitated overland flow was perceived to be the cause of gullying both in the case of dambo cultivation and dambo grazing, this overland flow re‐excavating what was believed to be fluviatile infill.

Geomorphological evidence is assembled to show that dambos are not ‘fossil’ fluviatile systems, nor is their clay infill alluvial. They are the ‘lows’ of a landsurface irregularly lowered by differential leaching. The infill forms by precipitation of materials leached from the interfluve profiles and discharged into the dambos. The fluviatile‐like configuration of dambos is attributed to integration of sub‐clay groundwater movement, resulting from landsurface incision. Accelerated gullying in Zimbabwe is deduced to be caused by breaching of the dambo clay by subsurface water movement. The particular vulnerability of Zimbabwe dambos is attributed to: (1) the watershed situation; (2) shallow weathering and (3) the thinness of the dambo clay. Evidence from Malawi indicates that interfluve deforestation and cultivation of shallow‐rooted crops conserve water, raising the groundwater level. Such an increased head of groundwater also appears to have occurred in Zimbabwe; this would strengthen upward discharge in the dambos, promoting gullying. Urgent land and water policy revision is required, allowing restoration of dambo cultivation and reafforestation of interfluves, if dambos are to be conserved and the resources which they offer satisfactorily utilized.
The nature and management of saprolite aquifers in the wheatbelt of western Australia
Authors: George Richard J.
Published: February 2007

Regional weathered‐zone goundwaters in the southern part of Western Australia are primarily stored in a granular saprolite aquifer derived from the isovolumetric weathering of granitic and gneissic rocks. Recent drilling has confirmed the existence of permeable materials capable of yielding groundwater of a suitable quality for livestock. Development of supplies of 10 to 250 kl d−1is realisic and would complement local livestock, domestic and Government water supply systems. Wheatbelt aquifers currently supply 18 to 25 per cent of all water used for livestock in the agricultural areas of the southern part of Western Australia, although less than 1 per cent of the available resource is being utilized. Unused groundwater, artificially recharged by water‐use inefficiencies of agricultural development, provides both a potential resource and a cause of soil and water quality deterioration.

Groundwater pumping may provide one method of aquifer control to mitigate the influence of secondary salinization. Pumping the low transmissivity Wheatbelt aquifers provides a means to lower water‐tables and limit the volume of groundwater reaching saline discharge areas at low points in the landscape. Unlike aquifer pumping systems developed in saline discharge areas, extraction systems in groundwater recharge areas, or in saline areas where groundwaters are of a suitable quality for agricultural use, can be used to mitigate salinity. The volume of groundwater available in southwestern Western Australia usually exceeds livestock requirements, to maintain low water‐tables, the water has either to be pumped to suitable drainage systems or alternative uses must be sought.
False expectations of labour participation in the construction of permeable infiltration dams in burkina faso
Authors: Vlaar J. C. J. , Brasser M. B.
Published: February 2007

Study of the labour participation in constructing permeable infiltration dams for soil and water conservation to increase agricultural production in the Province of Bam, Burkina Faso, revealed a progressive decline in cooperation at the village level, despite the high profitability of the completed structures*. This decline was mainly because not all the participating people could obtain such a dam for themselves due to constraints in rights to land and limited possibilities for an individual to mobilize labour. Development agencies can stimulate better labour participation by organizing cooperation on a smaller scale (i.e. village section or ‘quartier’, instead of village) or, probably with more success, by putting project means at the disposal of individual farmers, to enable them to mobilize labour for constructing permeable infiltration dams on their own plots.
The degradation of the algerian environment through economic and social ‘development’ in the 1980s
Authors: Zaimeche S. E. , Sutton K.
Published: February 2007

Concern for the better management of environmental resources grew during the 1980s. While this concern encompassed the misuse of the Third World's resources, those nations' governments and their peoples showed less awareness of the environmental damage being done in their quest for development. Environmental degradation has reached serious proportions in Algeria where oil wealth has masked failings of agricultural production and, together with industrialization, has provided a ‘veneer’ of economic development.

The vulnerability of Algeria's natural environment and the fragility of its ecosystems have been stressed by Cǒte (1983). Once cleared, Algeria's woodlands and forests are slow to re‐establish and surface deposits are easily erodable. Soils were largely formed under past climatic conditions, and so cannot be restored naturally by present pedogenetic processes. Such an environment is difficult and delicate to exploit to any high degree of agricultural intensification and is under increasing demographic pressure. Culturally and organizationally the agricultural system is far from ideal if agriculture is to be sustained. Often in Algeria the highest rainfall falls on the steeper slopes while the gentler slopes receive insufficient for agriculture. Only 500 000 hectares out of Northern Algeria's 38–40 million hectares receive more than 600 mm of rainfall and have slopes of less than three per cent (Cǒte, 1983). As much as 20 million hectares of Northern Algeria were identified by Dregne (1983) as … ‘vulnerable to desertification’ with large areas falling into his ‘severe’ risk category.

This study seeks to demonstrate the dimensions of environmental degradation through observations and the monitoring (during the 1980s) of Algeria's media: largely newspaper and television reports. Particular emphasis is placed on the growing environmental ‘crisis’ since 1988. It should be stressed that the Algerian Government uses a controlled media to disseminate official information. Misuse and overuse of environmental resources have combined with inadequate government economic policies and a neglect of ecological issues to cause the ‘crisis’.
Adoption of soil conservation practices: An empirical analysis in Ontario, Canada
Authors: Smit B. , Smithers J.
Published: February 2007

Soil degradation threatens environmental quality and sustainable food production. As a result of efforts to promote soil conservation, farmers in Canada are thought to be reasonably aware of both the importance of conservation and the existence of remedial and preventive practices. Despite this, the adoption of conservation practices has been less than overwhelming. Forces other than awareness and positive attitude seem to be constraining many land managers from employing available conservation methods. This paper presents the findings from an empirical investigation of the use of soil conservation practices and barriers to their adoption in the southwestern region of Ontario, Canada. The analysis is set in the context of literature on technology adoption. A scheme for measuring farm‐level conservation effort is developed, and barriers to adoption are derived from an analysis of a range of independent physical, personal, and economic factors, and from the obstacles or constraints identified by producers themselves. Key barriers relate to economic pressures, the complexity and compatibility of practices, and perceptions regarding the actual need for practices. The findings have relevance for the design of public policies and programs, notably the importance of supplying information on farm‐level implications of conservation methods and the need for a stable economic environment for agriculture to allow longer‐term planning.