Coralline algal nodules off Fraser Island, eastern Australia

Summary Calcareous red algal nodules growing on mobile substrates have been sampled from 28 to 117m off Fraser Island in southern Queensland, eastern Australia. This is a subtropical, transitional area between the tropical Great Barrier Reef to the north and temperate, cooler waters to the south. Red algal nodules are the most common components in bioclastic gravels that extend from about 50 to 110 m and locally cover 40–50% of the seafloor. Variations in the overall character and floristic composition of the nodules with depth can be observed. Algal nodules comprise algal covered pebbles/cobbles and rhodoliths in depths shallower than 60 m whereas only rhodoliths occur in deeper settings. No changes in nodule shape occur but shallower algal nodules have larger mean size with higher standard deviation than the deeper ones (39.2 vs. 30.5 mm and 20.5 vs. 6.3 mm s.d.). Living and subrecent red algae in nodules shallower than 60 m are mainly Melobesioideae and peyssonneliaceans with minor Lithophylloideae and Mastophoroideae. Most plants belong to a few species of the generaPhymatolithon andLithothamnion. Below 68 m, rhodoliths are dominated by the family Sporolithaceae, melobesioids and peyssonneliaceans.Sporolithon is the main component below 80 m. Algal growth forms are mostly smooth encrusting to warty with no depth variation. Maximum plant thickness, however, decreases with increasing depth. Thallus thickness in the deeper water samples is more than three times smaller than in those from shallower waters. These data are important for understanding the paleoenvironmental context of deposition of the abundant coralline algal limestones with similar algal nodules found in the geological record.     

Caesium-137 profiles in the sediments of a partial-meromictic lake on Great Sandy Island (Fraser Island), Queensland,Australia

Hidden Lake is a perched, brown-water lake located in the centre of Great Sandy Island (Fraser Is.), S.E. Queensland. It is highly acid (pH 4.0), oligotrophic and is thermally and chemically stratified for most of the year. The sediments revealed a ¹³⁷Cs profile which departed from the temporal pattern of ¹³⁷Cs fallout in Brisbane and was represented by an exponential increase of ¹³⁷Cs towards the surface sediments from ca. 32 cm depth. The possible causes of the divergent profile are discussed, including physical and biological mixing, lag in the transport of catchment material to the sedimentary basin, diffusion, recycling and biological concentration. It is hypothesised that a combination of the last four processes, with diffusion facilitated by the highly acid conditions, are the major causes of the observed ¹³⁷Cs profile. Possible recycling and bioconcentration of ¹³⁷Cs raises questions as to the validity of this method of dating in similar environmental conditions, and as to the interpretation of other palaeochemical data. These hypotheses are to be tested against profiles obtained from ¹⁴C, ²¹⁰Pb, ^239/240Pu analyses of the sediment, and the measurement of ¹³⁷Cs activity in the water and biota of the lake.     

Towards eradication: The history and management of Bitou Bush on K'gari‐Fraser Island,Australia

Persistence and dedication over the long term has been a key to success in control of this Weed of National Significance on World Heritage Listed K'gari‐Fraser Island in Queensland, Australia. Systematic surveys and treatment show that the goal of Bitou Bush eradication is worthwhile and can inspire other such projects within the region and beyond.     

Dune stabilization in Queensland,Australia, using vegetation and mulches

Coastal dunes in Queensland are usually vegetated because climatic conditions favour the growth of dune plants. Occasionally extreme climatic conditions, e.g. gales, droughts, wave erosion, or man's activities, e.g. grazing, access, development, destroy dunal vegetation and onshore winds move sand inland, accelerating coastal erosion. Replacement of vegetation is indicated in severe cases. The paper described trials done on Stradbroke Island into methods of re-establishing vegetation on dunes using different surface mulch treatments, including organic materials (straw and brush), and spray-on emulsions (bitumen, P.V.A. mineral oil-synthetic latex). All treatments (except the oil-latex emulsion) allowed ready establishment of vegetation. The bitumen and P.V.A. treatments could be used to replace the traditional organic mulches, subject to certain conditions. Data is presented on climate, soil temperatures, resistance to wind erosion plant ground covers and densities.Presented during the Seventh International Biometeorological Congress, 17–23 August 1975, College Park, Maryland, USA.     

人工樟子松—差不嗄蒿植被及其固沙作用

植物固沙是整治沙漠和沙漠化土地的一种有效措施。人工植被的建立是植物固沙的必然结果。人工植被的演替、稳定性及其对环境的影响直接关系到流沙的固定程度。因此,本文旨在探讨人工樟子松(Pinus sylvestris var.     

Microbial Diversity in Soil,Sand Dune and Rock Substrates of the Thar Monsoon Desert,India

A culture-independent diversity assessment of archaea, bacteria and fungi in the Thar Desert in India was made. Six locations in Ajmer, Jaisalmer, Jaipur and Jodhupur included semi-arid soils, arid soils, arid sand dunes, plus arid cryptoendolithic substrates. A real-time quantitative PCR approach revealed that bacteria dominated soils and cryptoendoliths, whilst fungi dominated sand dunes. The archaea formed a minor component of all communities. Comparison of rRNA-defined community structure revealed that substrate and climate rather than location were the most parsimonious predictors. Sequence-based identification of 1240 phylotypes revealed that most taxa were common desert microorganisms. Semi-arid soils were dominated by actinobacteria and alpha proteobacteria, arid soils by chloroflexi and alpha proteobacteria, sand dunes by ascomycete fungi and cryptoendoliths by cyanobacteria. Climatic variables that best explained this distribution were mean annual rainfall and maximum annual temperature. Substrate variables that contributed most to observed diversity patterns were conductivity, soluble salts, Ca²⁺ and pH. This represents an important addition to the inventory of desert microbiota, novel insight into the abiotic drivers of community assembly, and the first report of biodiversity in a monsoon desert system.     

Vegetation,land use and management of the inner-dune zone in the North-Holland Dune Reserve,The Netherlands

The inner-dune zone between the villages of Bakkum and Egmond in the North-Holland Dune Reserve is one of the few remaining examples of the semi-natural boundary between the dunes and the polders. For several centuries this area has been used for various purposes, in particular for grazing. Large-scale excavating, especially after about 1900, has encroached upon the dunes. Vegetation and land-use history were studied and a provisional scheme on the vegetation development is presented. Management policies discussed are non-intervention, mowing in order to start natural processes such as rabbit grazing, and the continuation of traditional livestock grazing. Proposals for external management policies were made in order to maintain or enhance the original transition zone, based on comprehensive physical-geographical studies of the whole inner-dune zone.     

Vegetation Monitoring of Created Dune Swale Wetlands, Vandenberg Air Force Base, California

A monitoring program was established on San Antonio Terrace at Vandenberg Air Force Base to compare vegetation development at two created wetland sites and six nearby natural wetlands. The reference wetlands were chosen to represent a range of habitats in dune swale wetlands on the Terrace. Vegetation in the reference wetland plant communities varies from low-growing herbaceous marsh species with open canopies to closed canopies dominated by shrub or tree species. Transects and plots for long-term vegetation monitoring were established in all the wetlands, stratified by plant communities in the reference wetlands and by geomorphic location in the newly created wetlands. Quantitative vegetation and environmental data were collected at all the sites; measures included species distributions, species cover, and topographical elevations. Over the first three years of monitoring, variations in groundwater depth at different geomorphic locations in the created wetlands resulted in a variety of physical conditions for plant growth. In the first year, more than 100 plant species were observed, the majority being natives. During the next two years, species richness at the created wetland sites remained relatively stable and was higher than at the reference sites. Statistical comparisons of vegetation parameters by analysis of variance and hierarchical clustering exhibited patterns of increasing similarity between the created and reference wetlands. Long-term monitoring will be continued to track the progress of vegetation at the created sites, and to assess their development relative to the reference wetlands.     

DNA Transport and Natural Transformation in Mesophilic and Thermophilic Bacteria

Comparative genome analyses revealed a massive DNA exchange between microbes of distant evolutionary lineages. This phenomenon known as horizontal, or lateral, gene transfer has a tremendous impact in the evolution of prokaryotes. Here, the process of DNA transport via genetic transformation is discussed. This review will focus on the process of DNA uptake mediated by type IV pilin-like proteins in Gram-positive and Gram-negative bacteria. Three tentative models of transformation machineries comprising components similar to proteins of type IV pili and type II secretion are presented. A comparative discussion of the structure of DNA translocators and the underlying mechanism of transfer of free DNA in mesophilic and extremely thermophilic bacteria highlights conserved and distinctive features of the DNA translocators in mesophilic and thermophilic bacteria.     

Natural and engineered biosynthesis of nucleoside antibiotics in Actinomycetes

Journal of Industrial Microbiology & Biotechnology - Nucleoside antibiotics constitute an important family of microbial natural products bearing diverse bioactivities and unusual structural...     

Sand Dune Restoration in North Brittany, France: A 10-Year Monitoring Study

Dunes, which account for 13% of the Ille et Vilaine north Brittany coast, France, were degraded by high tourist pressure, and they were restored from 1988 onward. Ten years after commencing work an assessment of the restoration was made on three dunes: Les Chevrets, L'Anse Du Guesclin, and Le Verger. Annual monitoring of the vegetation and dune morphology provided an opportunity to study the restoration process. The dune front, which is similar to a reference pioneer dune, lies in front of the mobile dune. The highest part of the dune is an advanced stage of mobile dune. The restoration of the fixed rear dune was accomplished neither in terms of vegetation composition nor in terms of species richness. The vegetation parameter study allows differentiation between the dune front, the dune summit, and the rear dune. The variation in species richness and floristic composition from one zone to another can be explained by abiotic factors such as salinity and the accretion of sand. The restoration was satisfactory in terms of the geomorphology. Marram grass is a good tool for restoring the topography, but it will take a very long time to restore the conservation value of the dune.     

放线菌来源活性天然产物发现研究进展

放线菌(Actinomycetes)是抗生素等活性天然产物的重要来源，在临床治疗病原菌感染等重大疾病方面发挥着重要作用。由于抗生素滥用等原因导致临床上出现的以耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus, MRSA)等为代表的耐药病菌的种类和数量急剧增加，对人类生存造成了重大威胁。结合现代生物技术进展，加大放线菌来源新抗生素的开发力度刻不容缓。本文对新时期放线菌来源抗生素的发现现状、基于生理操作和基因操作的放线菌来源天然产物挖掘的技术方法等进行综述，以期对放线菌来源活性天然产物的发现提供借鉴。     

Vegetation,microclimate and soils associated with the latest-lying snowpatches in Australia

Background : The Snowy Mountains contain Australia's longest-lasting snowpatches. Because of climate change, their longevity has declined, with the loss of some specialist vegetation in the underlying snowbeds.

Aims: To characterise the current status of the vegetation associated with the longest-lasting snowpatches in Australia and its association with abiotic factors.

Methods: We assessed plant composition, soil depth, moisture and nutrients and subsurface temperatures in five zones of increasing vegetation height and cover in snowbeds.

Results: The zone beneath the middle of snowpatches was characterised by little vegetation cover and lower species richness, later emergence from snow, skeletal soils, and lower mean soil temperatures than zones further downslope where soils increased in depth and nutrient levels. Vegetation beneath these snowpatches no longer occurs in distinct communities. Plants have not simply migrated upslope, instead, areas that have deep soil that used to have snowpatch specialist species are being colonised upslope by grasses and downslope by tall alpine herbfield species that prefer bare ground.

Conclusions: Reduced longevity of Australia's longest-lasting snowpatches has led to the loss of distinct snowpatch plant communities. With limited soils beneath the centre of current snowpatches, and a lack of other suitable sites there is no location for these plant communities to migrate to.     

海南岛儋县宝岛新村自然植被的变迁及其对环境的某些影响

本文报道了宝岛新村近三十年来自然植被的破坏,及其在以下几方面的反应：1．植被逐渐矮化,组成种类逐渐减少,木本植物由五十年代初期的211种减少到目前的102种。2．野生动物也日益减少,有21种鸟类已不复存在。3．土壤肥力衰退,其结果是作物产量逐年下降,生物产量低下,以及某些喜阴嗜肥植物消失和耐旱耐瘠植物侵入。     

外马廊山岛植被特性与植物多样性

该研究对无居民海岛舟山外马廊山岛进行初步踏勘,了解该岛植被特征与植物多样性,探讨海岛植被与大陆植被的差异性,并对海岛植物的主要植物组成、生活型结构、地理成分、群落类型以及多样性和相似性进行了分析。结果表明:外马廊山岛面积小,共有33科51属55种植物,植物种类偏少,留存有普陀狗哇花,滨柃,厚叶石斑木等具有滨海特色植物,具有开发潜力。外马廊山岛热带成分较为明显,与附近地区较为相似。岛上群落优势种或建群种的科为山茶科,大戟科,松科等,与大陆的常绿阔叶林的优势种或建群种的优势科如樟科,金缕梅科,壳斗科,山茶科等不大相同。岛上植物主要以高位芽植物为主(58.18%),但较大陆常绿阔叶林的高位芽植物比例要低。外马廊山岛植物群落结构简单,植物多样性相对较低,物种丰富较低,主要原因在于生态适应性和演替过程的差异,岛上植物群落演替至稳定群落还需要相当一段时间。外来种比例占9.09%,外来种如黑松和红鸡竹能形成群落或在群落中具有较为明显的优势,并可能会造成一定的生态干扰。     

Structure, Pattern and Mechanisms of Formation of Seed Banks in Sand Dune Systems in Northeastern Inner Mongolia, China

A comparison of structure and pattern of the soil seed bank was made between active and stabilized sand dunes in northeastern Inner Mongolia, China. The objective of this paper was to determine the significance of seed bank in vegetation restoration of sand dunes. The results showed that (1) average seed density decreased from stabilized sand dune to interdune lowland of stabilized sand dune, to interdune lowland of active sand dune, and to active sand dune; (2) horizontally, along the transect from interdune lowland to ecotone and to sand dune top, a ‘V’ shaped pattern was presented in the active dune system, and a reverse ‘V’ shaped pattern in the stabilized sand dune system; (3) vertically, the proportion (accounting for the total seeds) of seeds found in 0–20 mm soil profile decreased from stabilized sand dune to interdune lowland of stabilized sand dune, to interdune lowland of active sand dune, and to active sand dune. The same order was also found in 20–50 mm and 50–100 mm soil profiles; (4) the Sokal and Sneath similarity indices in the species-composition between soil seed bank and above-ground vegetation were ranked as: the stabilized sand dune (24%) > the interdune lowland of active sand dune (21%) > the interdune lowland of stabilized sand dune (18%) > the active sand dune (5%); and (5) vegetation restoration of active sand dunes depends on the dispersal of seeds from nearby plant communities on the interdune lowlands. Much effort must be made to preserve the lowlands, as lowlands are the most important seed reservoir in the active sand dune field.     

A Preliminary Study of Microalgae in the Intertidal Zones of the Deception Island,Antarctica

his paper first presents a report on the composition and distribution of microalgae in the intertidal zones of the Deception Island, Antarctica. These microalgae samples were collected from six mud-sand flats stations on 21 January 1987. 179 taxa of microalgae belonging to Bacillariophyta (125 species, 25 varieties and 2 forma, 34 genera), Cyanophyta (18 species and 2 varieties, 6 genera), Pyrrophyta (6 species, 4 genera) and Chrysophyta (1 species 1 genus) were observed. The six dominant microalgae in each habitat are Fragilaria bongrainii, F. oceanica, F. striatula, F. islandica, Navicula antarctica and Synedra kerguelensis var. antarctica. Rhabdonema arcuatum, Cocconeis antiqua and Licmophora gracilis are abundant in station 4, 5 and 6. Oscillatoria spp., Lyngbya antarctica, Phormidium antarcticum and Nodularia spp. are also abundant in station 1, 2 and 3. The values of diversity indice for microalgae varied from 2. 85 to 6.86. The values of similarity indice in microalgae composition between biotopes ranged from 32 to 79 for pairs of stations. Microalgal species composition and quantitative distribution are depended on per cent contents of mud-sand and claysilt at different stations.     

Pathogens of house mice on arid Boullanger Island and subantarctic Macquarie Island, Australia

Studies on island populations of house mice (Mus domesticus) and their viruses reveal insights into viral persistence in isolated communities. We surveyed the ectoparasites, endoparasites, and antiviral antibodies for 11 murine viruses and two bacteria of house mice inhabiting two islands off Australia. House mice on Boullanger Island were seropositive to two viruses, murine cytomegalovirus and epizootic diarrhea of infant mice. On subantarctic Macquarie Island, house mice were seropositive for five viruses: murine cytomegalovirus, lymphocytic choriomeningitis virus, mouse parvovirus, epizootic diarrhea of infant mice, and Theiler's murine encephalomyelitis virus. The diversity of antiviral antibodies was lower among populations of house mice on islands than those inhabiting mainland Australia. The decreased diversity of viruses in island populations of house mice may be a function of which agent the founder mice transfer to the island and related to the low densities which the host population may periodically reach over time.     

Persistence of Coastal Vegetation in Supratidal Zones of Northern China

Coastal vegetation comprises a number of coastal specialists and terrestrial generalists. It remains unclear how they persist on disturbed and undisturbed coastal conditions. We tested the hypothesis that coastal specialists may be superior to terrestrial generalists on supratidal zones of coasts, but their superiority can be influenced by human disturbances. Eight separate sandy coasts of the Shandong Peninsula were sampled, representing for disturbed and undisturbed sandy coasts. Plants growing on their supratidal zones were surveyed. On this basis, we compared the relative dominances, niche widths, and commonness of all species, and also analyzed species diversities of the coasts. Coastal specialists were found to be more common and widespread on supratidal zones of the sandy coasts than terrestrial generalists haphazardly invading from hinterlands. Coastal specialists exhibited lower Sørensen dissimilarities than terrestrial generalists among the coasts. Tourist trampling seemed more detrimental than pond fishery to coastal vegetation. Relative to terrestrial generalists, coastal specialists responded to human disturbances more deterministically, with steady decreases in species diversities. These evidences verify that coastal specialists are intrinsically superior to terrestrial generalists on supratidal zones of coasts, especially of undisturbed coasts, because their dispersal among coasts adapts well to local storm surge regime. They also validate that human disturbances can depress the superiority of coastal specialists, partly by inducing invasion of terrestrial generalists.