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We used multiple stable-isotope analysis to investigate the importance of seagrasses, mangroves and other primary sources (macroalgae, seston) to the food webs supporting penaeid prawns in the Embley River estuary and adjacent off-shore waters in the north-eastern Gulf of Carpentaria, Australia. Mangroves, seagrass and macroalgae/seston were well separated on the basis of their δ13C values in both the dry and the wet seasons. In contrast, only macroalgae and seston (phytoplankton and zooplankton), which had similar δ13C values, were separated by their δ15N values. The primary source of carbon supporting food webs of several species of juvenile penaeid prawns clearly depended on the location within the estuary. The δ13C values of juvenile prawns (Penaeus esculentus, P. semisulcatus and Metapenaeus spp.) in seagrass beds were close to those of seagrass and seagrass epiphytes, particularly in the dry season. This was despite the proximity of the seagrass to mangroves and the presence of mangrove detritus in the seagrass beds. Juvenile prawns (P. merguiensis, P. semisulcatus, and Metapenaeus spp.) in an upstream mangrove creek had δ13C values that were midway between those of mangroves and seagrass, and close to those of macroalgae and seston during the dry season. Mangroves could have made a significant contribution to the carbon assimilated by juvenile prawns at this site, but only if it is assumed that the remainder of the carbon is ultimately derived from a seagrass source. The δ13C values of adults of three species of prawns in offshore waters were very similar and were much higher than those of mangroves. The considerable amount of mangrove/terrestrial carbon exported from tropical Australian estuaries during the wet season is therefore unlikely to contribute to offshore food webs supporting adult prawns. Furthermore, the contribution of mangrove/terrestrial sources to the food webs of juvenile prawns appears to be limited to a very small spatial scale – within the mangrove fringe of small creeks and mainly during the wet season.

Physical disturbance owing to spates can have a significant influence on the structure and dynamics of periphyton assemblages in streams. The effects of flooding on epilithic algae in two subtropical rainforest streams was investigated. Periphyton chlorophyll a and biomass (mainly of diatom origin) were monitored over three and a half years in relation to rainfall and stream discharge. High discharge events had a reducing effect on periphyton chlorophyll a and biomass in both streams. However, these values recovered quickly (within a period of approximately 10–30 days post-spate) in the absence of any further disturbance. After approximately 60 days, however, levels declined in the absence of subsequent disturbances. Differences in the epilithon between the two streams could be related to the geomorphology and the pattern of disturbance. Cobbles in the steeper-gradient stream-reach supported more chlorophyll a containing material of algal origin and less non-algal biomass than those in the low-gradient stream-reach. Overall, changes in the standing crop of epilithic algae could be attributed directly to the effects of spates. However, some major variations in chlorophyll a and biomass occurred in the absence of high discharge events, suggesting that other factors, such as extreme low flows, could also be significant agents of disturbance.

Analysis of genetic variation among populations of stream invertebrates provides a measure of the consequences of effective dispersal, and can be used to determine the extent of movement within and between streams and to infer the likely mechanisms involved. In our recent studies of rainforest stream invertebrates, we have found considerable genetic differentiation among populations of fully aquatic taxa, indicating limited in-stream movement on a very small scale. Adult flight appears to be the principal mechanism of dispersal for aquatic insects; however, analysis of the genetic structure of larval populations of some species also suggests that in-stream movement is limited to a small spatial scale. Furthermore, detailed analysis of the genetic structure of larval populations suggests that recruitment at the reach scale is the result of only a few adult matings and most likely from oviposition by only a few females. We propose that dispersal capability and the stochastic effects of recruitment are key d...

We examined the potential of using an enriched stable isotope ( 15 N) to trace the assimilation of individual protein sources from compound aquaculture diets by juvenile Penaeus monodon . We used the marine diatom Chaetoceros muelleri as a source of plant protein and the brine shrimp ( Artemia ) as a source of animal protein. The diatoms were labelled by replacing 5% of the nitrogen in their culture nutrient media with 15 N enriched KNO 3 . The Artemia were labelled by feeding them 15 N enriched diatoms. The 15 N enriched diatoms and Artemia were each incorporated into a standard compound pelleted diet. The pellets were fed to juvenile P. monodon (weight range 2 to 5 g) in the laboratory and in enclosures at a local prawn farm. Analysis of the percentage 15 N in the abdominal muscle of juvenile prawns demonstrated rapid assimilation of the enriched isotope from diatoms and Artemia . There was a progressive increase in the percentage 15 N in the abdominal muscle during the 4-week experiment. Application of a simple mixing model showed that the relative assimilation rate of enriched nitrogen from Artemia was approximately 4.3 times that of the diatoms after 2 weeks and approximately 3.6 times that of diatoms after 4 weeks. The results demonstrated that enriched stable isotope tracers can provide rapid and direct information about the assimilation and retention of nitrogen from individual protein sources in compound diets for shrimp.

1. Caridina zebra is a common atyid shrimp in some tropical rainforest streams in far north Queensland, Australia. Genetic variation at five allozyme loci was used to estimate the level of dispersal among populations of this species, within and between stream systems. Shrimps were sampled from nine streams in the Tully River catchment and two headwater streams in the adjacent Herbert River catchment in an area under consideration for extensive hydroelectric development. 2. High levels of genetic differentiation were recorded among most populations which suggests that, like other fully aquatic species, movement is limited to a very small spatial scale. 3. In the Tully catchment, populations of shrimp from streams with confluences at high altitude showed less genetic differentiation than those from streams which directly entered the lower river. Dispersal between the latter streams is clearly limited by the presence of large waterfalls and cascades. 4. Adjacent stream populations were often highly differentiated, despite their close proximity, suggesting that overland dispersal is unlikely. However, populations of shrimp in the two streams in the Herbert catchment were strikingly similar in genetic structure to those in adjacent headwater streams of the Tully. Such similarity may reflect relatively recent changes in drainage patterns.

A survey of 91 e-mail enquiries to Diabetes UK showed evidence of a substantial un-met need for better quality dietary advice, both at the time of diagnosis and during follow up. There was evidence of inadequate and inappropriate advice and of conflicting advice from different health care professionals. Many of those who were newly diagnosed were confused about what they should and should not eat. Doctors and nurses who give dietary advice need better training in current nutritional principles. People with type 1 diabetes should be seen by a state registered dietitian within two days of diagnosis and those with type 2 diabetes within one month. All patients should be offered an annual dietetic review with a state registered dietitian and there should be provision for those who need more frequent review. Copyright © 2004 John Wiley & Sons, Ltd.

We investigated the effects of acid washing on the carbon and nitrogen composition and stable isotope ratios of C and N in shrimp (Metapenaeus spp.) and seagrass (Enhalus acoroides). Acid washing did not affect the mean 6’ 3C ratios for juvenile Metapenaeus moyebi and resulted in only an ecologically insignificant change (0.3%0) in mean P3C ratios for larger Metapenaeus bennettae. In contrast, acid washing increased the mean 615N signatures of shrimp tissue (- 3G) and decreased that of seagrass (N 1.89&) to a degree that may confound the interpretation of food webs. The increase in %C and %N in both shrimp and seagrass after acid washing suggests that the changes in isotope ratios are due to loss of molecules comparatively low in C and N. Treating samples by acid washing also resulted in an increase in the variation among individuals for both 615N and 613C, which would lead to a loss of statistical power for testing differences between species, sites, or seasons.

Biological methods are widely accepted in water quality monitoring programmes worldwide; however, some concern remains over their effectiveness in predicting the effects of contaminants on aquatic ecosystems. While the so-called‘early warning’ approaches, such as bioassays and biomarkers, have been used in Australia to demonstrate mechanisms of toxic action and exposure to contaminants, as elsewhere, little attempt has been made to link observed effects at these lower levels of biological organization to real impacts on aquatic systems. The ecological consequences of exposure to contaminants is undoubtedly best studied at higher levels of biological organization (i. e. at the population or community level). However, monitoring aquatic communities is labour intensive and inadequate for the early detection of impacts. Research is needed to identify links between the bioassessment measures used, so that changes at the lowest biological level (e. g. using biomarkers and bioassays) can be translated into likely‘real’ impacts on the aquatic system, as measured at the population or community level. Monitoring the genetic structure of populations of aquatic organisms, particularly invertebrates, may provide a potential link between subtle effects observed in bioassay tests and subsequent changes in population density and/or community structure. A streamlined approach to monitoring changes at the community level needs to be developed to improve predictive ability and to make this approach more responsive to the early detection and prevention of unacceptable impacts. In addition, research on the use of ecosystem level parameters, such as production/respiration ratios or community metabolism, should be undertaken to determine their suitability for routine biomonitoring of water quality in Australian inland waters.

We used measures of genetic differentiation at seven allozyme loci to estimate the degree of movement of a stream invertebrate within and between catchments. Populations of Paratya australiensis, a common atyid shrimp, were sampled from three rainforest streams from each of two subcatchments in two adjacent drainage systems in southeast Queensland. Marked genetic differentiation was observed at all loci, suggesting extremely limited movement on a small spatial scale. This result is surprising given the widespread geographic distribution of P. australiensis in Australia, its great abundance in headwater streams in southeast Queensland, and the presence of a planktonic larval stage. Large differences in genetic structure occurred between streams, in some instances between those in the same subcatchment. Even larger genetic differences were seen between samples from streams in different subcatchments, with alternative alleles being fixed at different sites. The greatest differences were not, however, between...

The genetic structure of populations of Baetis sp. (Ephemeroptera:Baetidae) was used to draw inferences about the means of dispersal within and between stream systems of the Conondale Range, Queensland, Australia. Allozyme electrophoresis was used to examine allelic frequencies at five variable loci in geographically distant populations of nymphs in the same drainage and in nearby populations in different drainages. The results showed widespread gene flow between drainages and a tendency for local differentiation. We concluded that adult flight represents an effective means for dispersal between drainage systems. The differentiation between populations at a local scale and erratic deviations from Hardy Weinberg equilibrium could have occurred if the nymphs collected from any stream were the offspring of only a few adults. If this is the case, the dispersal capabilities of nymphs by swimming, crawling or drift may be minimal even within a single stream.

Diatoms have been regularly used as bioindicators to assess water quality of surface waters. However, diatom-based indices developed for a specific geographic region may not be appropriate elsewhere. We sampled benthic diatom assemblages in the upper Han River, a subtropical river in China, to evaluate applicability of 14 diatom-based indices used worldwide for water quality assessment. A total of 194 taxa from 31 genera were identified in the dry season and 139 taxa from 23 genera in the wet season. During the dry season, significant relationships were found for all but one of the diatom-based indices (Index Diatom Artois–Picardie) with one or more physical and chemical variables including nutrients and ion concentrations in river waters. The Biological Diatom Index (IBD) and diatom-based eutrophication/pollution index (EPI-D) were strongly related to trophic status and ionic content, while Watanabe’s Index was related to organic pollution and conductivity. Yet, the diatom indices showed weak relationships with physical and chemical variables during the wet season. It suggests that diatom-based indices developed in Europe can be applied with confidence as bioindicators of water quality in subtropical rivers of China, at least during base-flow conditions.

Murray-Darling Freshwater Research CentreMDFRC item.The use of stable isotopes to identify the structure of aquatic food webs is predicted upon there being significant and consistent differences in the isotopic composition of the various classes of primary producers. The structure of food webs will be interpreted incorrectly if variations in the isotopic composition of primary producers are not taken into account. We detected significant temporal and spatial variations in the δ13C and δ15N values of aquatic plants collected from three small, lentic water bodies in south-eastern Australia. Carbon- and nitrogen- isotope values of individual taxa could each vary by up to 10 delta units, according to site and season. The magnitude of these variations is sufficiently great for them to have important consequences for the interpretation of aquatic food webs. Greater attention must be given to fluctuations in the isotopic signatures of the primary producers if the structure of aquatic food webs is to be properly understood.

1. Despite implications for top-down and bottom-up control and the stability of food webs, understanding the links between consumers and their diets remains difficult, particularly in remote tropical locations where food resources are usually abundant and variable and seasonal hydrology produces alternating patterns of connectivity and isolation. 2. We used a large scale survey of freshwater biota from 67 sites in three catchments (Daly River, Northern Territory; Fitzroy River, Western Australia; and the Mitchell River, Queensland) in Australia's wet-dry tropics and analysed stable isotopes of carbon (δ(13) C) to search for broad patterns in resource use by consumers in conjunction with known and measured indices of connectivity, the duration of floodplain inundation, and dietary choices (i.e. stomach contents of fish). 3. Regression analysis of biofilm δ(13) C against consumer δ(13) C, as an indicator of reliance on local food sources (periphyton and detritus), varied depending on taxa and catchment. 4. The carbon isotope ratios of benthic invertebrates were tightly coupled to those of biofilm in all three catchments, suggesting assimilation of local resources by these largely nonmobile taxa. 5. Stable C isotope ratios of fish, however, were less well-linked to those of biofilm and varied by catchment according to hydrological connectivity; the perennially flowing Daly River with a long duration of floodplain inundation showed the least degree of coupling, the seasonally flowing Fitzroy River with an extremely short flood period showed the strongest coupling, and the Mitchell River was intermediate in connectivity, flood duration and consumer-resource coupling. 6. These findings highlight the high mobility of the fish community in these rivers, and how hydrological connectivity between habitats drives patterns of consumer-resource coupling.

Little is known about the threat of mercury (Hg) to consumers in food webs of Australia's wet-dry tropics. This is despite high concentrations in similar biomes elsewhere and a recent history of gold mining that could lead to a high degree of exposure for biota. We analysed Hg in water, sediments, invertebrates and fishes in rivers and estuaries of north Queensland, Australia to determine its availability and biomagnification in food webs. Concentrations in water and sediments were low relative to other regions of Hg concern, with only four of 138 water samples and five of 60 sediment samples above detection limits of 0.1 mu g L-1 and 01 mu g g(-1), respectively. Concentrations of Hg in fishes and invertebrates from riverine and wetland food webs were well below international consumption guidelines, including those in piscivorous fishes, likely due to low baseline concentrations and limited rates of biomagnification (average slope of log Hg vs. delta N-15 = 0.08). A large fish species of recreational, commercial, and cultural importance (the barramundi, Lates calcarifer), had low concentrations that were below consumption guidelines. Observed variation in Hg concentrations in this species was primarily explained by age and foraging location (floodplain vs. coastal), with floodplain feeders having higher Hg concentrations than those foraging at sea. These analyses suggest that there is a limited threat of Hg exposure for fish-eating consumers in this region. (C) 2011 Published by Elsevier B.V.

High levels of hydrological connectivity during seasonal flooding provide significant opportunities for movements of fish between rivers and their floodplains, estuaries and the sea, possibly mediating food web subsidies among habitats. To determine the degree of utilisation of food sources from different habitats in a tropical river with a short floodplain inundation duration (~2 months), stable isotope ratios in fishes and their available food were measured from three habitats (inundated floodplain, dry season freshwater, coastal marine) in the lower reaches of the Mitchell River, Queensland (Australia). Floodplain food sources constituted the majority of the diet of large-bodied fishes (barramundi Lates calcarifer, catfish Neoarius graeffei) captured on the floodplain in the wet season and for gonadal tissues of a common herbivorous fish (gizzard shad Nematalosa come), the latter suggesting that critical reproductive phases are fuelled by floodplain production. Floodplain food sources also subsidised barramundi from the recreational fishery in adjacent coastal and estuarine areas, and the broader fish community from a freshwater lagoon. These findings highlight the importance of the floodplain in supporting the production of large fishes in spite of the episodic nature and relatively short duration of inundation compared to large river floodplains of humid tropical regions. They also illustrate the high degree of food web connectivity mediated by mobile fish in this system in the absence of human modification, and point to the potential consequences of water resource development that may reduce or eliminate hydrological connectivity between the river and its floodplain.

This study examined the link between terrestrial and aquatic phosphorus (P) speciation in the soils and sediments of a subtropical catchment. Specifically, the study aimed to identify the relative importance of P speciation in source soils, erosion and transport processes upstream, and aquatic transformation processes as determinants of P speciation in lake sediments (Lake Wivenhoe). Using a sequential extraction technique, NH(4)Cl extractable P (NH(4)Cl-P; exchangeable P), bicarbonate-dithionite extractable P (BD-P; reductant soluble P), NaOH extractable P (NaOH-rP; Al/Fe oxide P), HCl extractable P (HCl-P; apatite-P), and residual-P (Res-P; organic and residual inorganic P) fractions were compared in different soil/sediment compartments of the upper Brisbane River (UBR) catchment, Queensland, Australia. Multidimensional scaling identified two distinct groups of samples, one consisting of lake sediments and suspended sediments, and another consisting of riverbed sediments and soils. The riverbed sediments and soils had significantly higher HCl-P and lower NaOH-rP and Res-P relative to the lake and suspended sediments (P < 0.05). Analysis of the enrichment factors (EFs) of soils and riverbed sediments showed that fine grained particles (

*University of Liverpool, Liverpool, United Kingdom; †Liverpool School of Tropical Medicine, Liverpool, United Kingdom; ‡Misurata Teaching Hospital, Misurata, Libya; §Kenya Medical Research Institute, Nairobi, Kenya; and ¶Centro Havana Children’s Hospital, Havana, CubaSerotype G9 may be the fifth most common human rotavirus serotype, afterserotypes G1 to G4. In three cross-sectional studies of childhood diarrhea,we have detected serotype G9 rotaviruses for the first time in Libya, Kenya,and Cuba. Serotype G9 constituted 27% of all rotaviruses identified,emphasizing the reemergence of serotype G9 and suggesting that futurehuman rotavirus vaccines will need to protect against disease caused bythis serotype.Group A rotaviruses are firmly established as the mostimportant etiologic agents of dehydrating gastroenteritis ininfants and young children worldwide (1). Severe rotavirusdisease is preventable by vaccination. The expected impactof rotavirus vaccines in reducing disease and death fromrotavirus infection will be most evident in developing coun-tries, where rotavirus causes up to 500,000 childhood deathsannually (2).Rotaviruses are nonenveloped viruses whose genomecomprises 11 segments of double-stranded RNA (dsRNA),contained in the core of the mature, triple-layered particle(1). Rotavirus serotypes are determined by neutralizing anti-body responses to each of the two outer capsid proteins, VP7(termed G serotype) and VP4 (termed P serotype). Ten Gserotypes and 7 P serotypes have been identified in humans(1). Since serotypes G1, G2, G3, and G4 together account for>80% of global human rotavirus strains, some vaccines aimto provide serotype-specific protection against these fourserotypes (1). However, in certain geographic settings, otherG types (e.g., G5, G8, and G9) may be epidemiologicallyimportant (1). Since their first report in 1987 in the United States,rotaviruses of serotype G9 had been rarely detected in thehuman population (3). Since 1995, however, serotype G9 hasbeen documented in India, Brazil, Italy, the United States,Bangladesh, Malawi, the United Kingdom, France, and Aus-tralia (4). Recent reports from Ireland (5), the Netherlands(6), Japan (7), and Thailand (8) further emphasize the widegeographic distribution of this serotype. We recently charac-terized rotavirus strains detected during studies of diarrhealdisease in children in Libya, Kenya, and Cuba. We identifiedserotype G9 rotaviruses in each of these countries, providingfurther evidence that serotype G9 has reemerged as a glo-bally important human serotype.

Protecting the world’s freshwater resources requires diagnosing threats over a broad range of scales, from global to local. Here we present the first worldwide synthesis to jointly consider human and biodiversity perspectives on water security using a spatial framework that quantifies multiple stressors and accounts for downstream impacts. We find that nearly 80% of the world’s population is exposed to high levels of threat to water security. Massive investment in water technology enables rich nations to offset high stressor levels without remedying their underlying causes, whereas less wealthy nations remain vulnerable. A similar lack of precautionary investment jeopardizes biodiversity, with habitats associated with 65% of continental discharge classified as moderately to highly threatened. The cumulative threat framework offers a tool for prioritizing policy and management responses to this crisis, and underscores the necessity of limiting threats at their source instead of through costly remediation of symptoms in order to assure global water security for both humans and freshwater biodiversity.

Many streams and rivers in the south-west of Western Australia have marginal salinities and only about half of the divertible surface water is fresh (< 3 g 1−1). Although salinization is recognised as the greatest threat to water resources throughout Australia, little is known of its effect on the biota. This paper gives the first quantitative description of the macroinvertebrate fauna of a salinized river system in south-western Australia.

1. Natural wetlands throughout the world are under threat from water resource development required to support an ever increasing population. In the Border Rivers Catchment in Queensland, Australia, a large irrigation industry and highly variable flow regime have necessitated the building of large on-farm water storages. With the decline in number and size of natural wetlands, the presence of these storages on the floodplain has raised the question of their suitability as alternative habitat for aquatic fauna. This paper explores the variety of water storage types in the Border Rivers Catchment and how their morphology compares with that of natural wetlands — in particular, factors likely to influence aquatic biodiversity. 2. Storages and natural wetlands formed two distinct groups based on morphology. Storages tended to be large, deep structures with a more regular shape while natural wetlands were irregular and shallow with large perimeters. Although there was a degree of variability amongst the storage sites, a large proportion fell into one group and were considered ‘typical storages’. Typical storages contained tailwater and had the following characteristics: situated 3 km from the source river, 10 years old, embankment height of 5 m, area of 400 000 m2, perimeter of 2.5 km and capacity of 1 700 000 m3. 3. Due to their uniform structure we believe that most on-farm storages are unlikely to support as diverse or abundant an aquatic population as natural wetlands. The presence of tailwater and associated chemicals is also likely to reduce the aquatic biodiversity of storages compared with natural wetlands. While they may be unsuitable as replacement wetlands, given their numbers they could provide significant aquatic habitat across the landscape, if managed effectively. Copyright © 2009 John Wiley & Sons, Ltd.

Analyses of 10 years of daily average total ozone data for March 15 and October 10 were carried out. These days were chosen as they correspond, respectively, to the maxima in occurrence of the polar ozone thinning phenomena in the northern and southern polar regions. Several conclusions of significance arise from these analyses. The NIMBUS-7 TOMS data provide one of the best data sets available, with which to monitor global ozone depletion. Utilizing the assumption that equatorial ozone levels remain stable, a self-consistent compensation for instrumental drift indicates a −0.70% annual drift in the TOMS data values, which needs correction. Correcting for the TOMS drift in the 1979–1988 March 15 and October 10 data shows that a global ozone depletion is occurring at the rate of 0.224% per year. These analyses show that the maximum ozone-depletion rate occurs in the polar zone containing the ozone thinning phenomena. The southern zone depletion rate is some three times greater than the northern (1.06% compared with 0.39% per year), and the rate in the southern zone remains significantly above the global depletion rate, even during absence of the ozone thinning phenomenon (0.47% per year). This decrease is alarmingly greater than predicted by scenario models.

Riparian zones, river-marginal wetland environments and flood plains are key landscape elements with a high diversity of natural functions and services. They are dynamic systems that are shaped by repeated erosion

The di-Zn(II) complex of 1,3-bis[ N1, N1'-(1,5,9-triazacyclododecyl)]propane with an associated methoxide ( 3:Zn(II) 2: (-)OCH 3) was prepared and its catalysis of the methanolysis of a series of fourteen methyl aryl phosphate diesters ( 6) was studied at s (s)pH 9.8 in methanol at 25.0 +/- 0.1 degrees C. Plots of k obs vs [ 3:Zn(II) 2: (-)OCH 3] free for all members of 6 show saturation behavior from which K(M) and kcat (max) were determined. The second order rate constants for the catalyzed reactions (kcat (max)/K(M)) for each substrate are larger than the corresponding methoxide catalyzed reaction (k 2 (-OMe)) by 1.4 x 10(8) to 3 x 10 (9)-fold. The values of k cat (max) for all members of 6 are between 4 x 10(11) and 3 x 10(13) times larger than the solution reaction at s (s)pH 9.8, with the largest accelerations being given for substrates where the departing aryloxy unit contains ortho-NO 2 or C(O)OCH 3 groups. Based on the linear Brønsted plots of k cat (max) vs s (s)pKa of the phenol, beta lg values of -0.57 and -0.34 are determined respectively for the catalyzed methanolysis of "regular" substrates that do not contain the ortho-NO 2 or C(O)OCH 3 groups, and those substrates that do. The data are consistent with a two step mechanism for the catalyzed reaction with rate limiting formation of a catalyst-coordinated phosphorane intermediate, followed by fast loss of the aryloxy leaving group. A detailed energetics calculation indicates that the catalyst binds the transition state comprising [CH 3O (-): 6], giving a hypothetical [ 3:Zn(II) 2:CH 3O (-): 6] complex, by -21.4 to -24.5 kcal/mol, with the strongest binding being for those substrates having the ortho-NO 2 or C(O)OCH 3 groups.

Net primary production is a fundamental ecological process that reflects the amount of carbon synthesized within an ecosystem, which is ultimately available to consumers. Although current ecosystem models of streams and rivers have placed variable emphasis on the importance of instream primary production to aquatic food webs, recent research indicates that aquatic algae are a significant contributor to food webs in tropical rivers and streams. This is in contrast to many well-studied north temperate latitude streams in deciduous forest ecosystems, which are thought to depend mainly upon terrestrial leaf litter and detritus-based food webs. A review of available literature suggests that rates of in-stream primary production in tropical regions are typically at least an order of magnitude greater than comparable temperate systems. Although nutrient status can significantly modify rates, the ultimate driver of aquatic primary production is light availability. Rates of benthic gross primary productivity in tropical streams range from 100 to 200mgCm-2 d-1 under shaded conditions to much higher values associated with open canopies. Light inputs to the channel can be controlled by stream orientation, with east-west channels receiving much more light compared to those orientated north-south. Rates of production for large tropical rivers are similar to those for streams, although factors that regulate production are different and hence they respond differently to human impact. Values for rivers range from 10 to 200mgCm-2 d-1 to more than 1000mgCm-2 d-1. Production is often limited by turbidity, which tends to be at a maximum after high flow events. In polluted tropical rivers, productivity responds to nutrient enrichment and can attain rates of 6000mgCm-2 d-1. The highest rates of production in tropical river systems typically occur in floodplains subject to seasonal inundation, where aquatic vascular plants dominate total productivity. These macrophytes (herbaceous vascular plants that can be primarily terrestrial or aquatic) can proliferate in situ or be transported from upstream. Rooted aquatic plants with emergent or floating leaves respond to the rising water level, sometimes elongating their stems at a rate of 20cmd-1, and many terrestrial plants tolerate prolonged submergence. These ecosystems can attain very high rates of primary production that rival those of intensively managed agro-ecosystems. Floodplain forest can also be a productive component of these ecosystems. Both attached algae (periphyton) and phytoplankton contribute substantially to algal production in floodplain waters. Floodplains are important for fodder and for nursery habitat for fish, which re-invade main channels when floods recede. Tropical rivers may flow into coastal mangrove ecosystems, where rates of productivity are variable and often dependent of methodologies of measurement. Rates of mangrove production range from 1300mgCm-2 d-1 in the T鲭inos Lagoon, Mexico to 1900-2700mgCm-2 d-1 in the Fly River estuary (Papua New Guinea). However, rates of phytoplankton growth within mangrove forests are low, probably controlled by shading and turbidity, and are comparable to those of tropical streams. As pressures for water resource development intensify, tropical fluvial ecosystems are coming under increasing pressure. It is important to understand how these ecosystems function and to ensure problems of developing water resources in temperate regions are not repeated in the tropics.

The presence of a thinned area or craterlike feature in the Arctic polar ozone layer during March, 1986 has been reported previously (Can. J. Phys. 67, 161 (1989)). In this paper the morphology of the reappearance of the crater from January to March, 1989 is described. It appeared over northern Europe in late January and moved over western Canada in late February. The minimum value of ozone in the crater floor had fallen from 300 DU (1 Dobson unit (DU) = 0.01 mm) in 1979 to a new low of less than 200 DU in 1989, which is similar to the thinned total ozone columns observed within the Antarctic ozone hole. Analysis of the available total ozone mapping spectrometer ozone measurements indicates that the crater could be explained by a combination of two mechanisms; a chemical process, which depleted the ozone concentrations at altitudes in the 14–22 km region, and a transport process, which shifted the altitude distribution of ozone upwards such as a vertical circulation cell. Although the Arctic ozone crater is similar in several aspects to the Antarctic ozone hole, there remain several differences; the issue is whether the crater and the hole are manifestations of the same phenomenon. We consider that the Arctic ozone crater is mainly produced by dynamic redistribution driven by tropospheric circulation features.

Benthic macroinvertebrates were quantitatively sampled from thirty sites along two river systems in southwestern Australia, and patterns in community structure related to physical and chemical parameters. Classification and ordination showed a major separation between upland and lowland sites, irrespective of river system. The change in benthic community structure reflected the rapid transition in geomorphology, stream hydraulics, and water chemistry as upland forested streams exit the Darling Escarpment to give rise to open rivers, disturbed by agriculture and urban development. One upland site was clearly influenced by a storage reservoir immediately upstream and consistently grouped with lowland sites; evidence of recovery was apparent at sites downstream. The remaining upland sites were separated on the basis of catchment; this was most likely related to stream flow permanence than any inherent catchment difference. A seasonal pattern was also detected for upland sites. Samples taken in summer or autumn were distinct from those taken in winter or spring. In constrast, lowland sites could not be separated into distinct groups on the basis of season or drainage basin. The presence of cosmopolitan and tolerant species with a high likelihood of dispersal, together with the homogeneous nature of the sites, may account for the high degree of similarity among benthic communities of sites along the lowland rivers. Much of the spatial and temporal variation in benthic community structure was explained by physical characteristics of the sites. Prediction of community type using chemical data alone was poor, however, this success could be improved by combining physical and chemical data, particularly for upland sites. The poor predictive success using chemical data was likely the result of the abrupt changes in the physical nature of the streams, and the absence of large spatial differences in water quality. The successful predictive relatioship betweenm benthic community structure and physical data will enable water management authorities to detect subsequent changes in water quality in these two river systems. The predictive power of the model could be assessed in adjacent river systems for which the patterns in benthic community structure are as yet unknown.

Comparaison de l'entomofaune des ruisseaux de l'Australie du sud-ouest avec celle d'autres ruisseaux de regions temperees d'Australie. Discussion de l'origine de la faible richesse specifique : isolement geographique, forte aridite historique, tres faible niveau de productivite primaire.

Deterrence, the hallmark of Cold War era security, needs to be adapted to fit the more volatile security environment of the 21st century. The Bush administration has outlined a concept for tailored deterrence to address the distinctive challenges posed by advanced military competitors, regional powers armed with weapons of mass destruction (WMD), and nonstate terrorist networks while assuring allies and dissuading potential competitors. The goal of deterrence is to prevent aggressive action or WMD use by ensuring that, in the mind of a potential adversary, the risks of the action outweigh the benefits, while taking into account the consequences of inaction. Deterrence requires detailed knowledge of the society and leadership that we seek to influence. U.S. decision makers will need a continuing set of comprehensive country or group deterrence assessments, drawing on expertise in and out of government, in order to tailor deterrence to specific actors and specific situations. The capabilities needed for tailored deterrence go beyond nuclear weapons and the strategic capabilities of the so-called New Triad, to the full range of military capabilities, presence, and cooperation, as well as diplomatic, informational, and economic instruments. The clarity and credibility of American messages in the mind of the deterree are critical to tailoring deterrence threats. U.S. policy makers need mechanisms to assess how their words and actions are perceived, how they affect each adversary's deterrence calculations, and how they might mitigate misperceptions that undermine deterrence.

We search for viable f(R) theories of gravity, making use of the equivalence between such theories and scalar-tensor gravity. We find that models can be made consistent with solar system constraints either by giving the scalar a high mass or by exploiting the so-called chameleon effect. However, in both cases, it appears likely that any late-time cosmic acceleration will be observationally indistinguishable from acceleration caused by a cosmological constant. We also explore further observational constraints from, e.g., big bang nucleosynthesis and inflation., Comment: 15 pages, 5 figures

The Moreton Bay Waterways and Catchments Partnership, now branded the Healthy Waterways Partnership, has built on the experience of the past 15 years here in South East Queensland (SEQ). It focuses on water quality and the ecosystem health of our freshwater, estuarine and marine systems through the implementation of actions by individual partners and the collective oversight of a regional work program that assists partners to prioritise their investments and address emerging issues. This regional program includes monitoring, reporting, marketing and communication, development of decision support tools, research that is directed to problem solving, and maintaining extensive consultative and engagement arrangements. The Partnership has produced information-based outcomes which have led to significant cost savings in the protection of water quality and ecosystem resources by its stakeholders. This has been achieved by: – providing a clear focus for management actions that has ownership of governments, industry and community; – targeted scientific research to address issues requiring appropriate management actions; – management actions based on a sound understanding of the waterways and rigorous public consultation; and, – development and implementation of a strategy that incorporates commitments from all levels of stakeholders. While focusing on our waterways, the Partnership’s approach includes addressing catchment management issues particularly relating to the management of diffuse pollution sources in both urban and rural landscapes as well as point source loads. We are now working with other stakeholders to develop a framework for integrated water management that will link water quality and water quantity goals and priorities.

To determine the accuracy of the resistance index (RI) of flow velocity waveforms of the umbilical artery measured using a newly developed PC-based continuous wave Doppler device (Umbiflow) with regard to systematic and random variations when compared with a commercial standard (Vasoflow).A cohort study.The fetal evaluation clinic (FEC) at Tygerberg Hospital.Patients referred to the FEC at Tygerberg Hospital with suspected chronic placental insufficiency.The correlation coefficients indicating the strength of the relationship between the two devices and their agreement using the method of Bland and Altman.A total of 248 patients were studied. The mean RIs of the first Doppler assessment were 0.69 (standard deviation (SD) 0.11) and 0.67 (SD 0.11) using the Vasoflow and Umbiflow respectively. The Pearson's correlation coefficient comparing the RI of the first test was 0.85. The degree of agreement between the two methods was excellent, the mean differences being very small (0.024) with tight confidence intervals. One hundred and ninety-four patients (78.2%) of patients remained in the same percentile category with both the Vasoflow and Umbiflow.The accuracy of the Umbiflow has been proved. A non-significant trend towards slightly lower values needs to be considered. This could be addressed by changing the percentile cut-off to slightly lower values.

Key Points By October 2004, the United States will have begun initial deployment of a missile defense capability--albeit a modest, limited, and not completely proven one--to defend the homeland against a limited ballistic missile attack. The gradual phase-in of ballistic missile defense deployments will mark an important change in the policy context of the missile defense issue. Past debate focused on whether missile defenses should be deployed and whether they would work. These issues will now share the limelight with another pressing question: how would missile defenses actually be used? Operating a missile defense system presents seven challenges: * to whom weapons release authority should be delegated * how limited missile defense assets should be allocated * what roles the President and Secretary of Defense should play during intercept operations * how strike options should be coordinated with defenses * which U.S. command should be responsible for conducting missile defense operations * how testing and operational requirements should best be balanced * what arrangements are needed to notify Russia when the United States launches missile defense interceptors, to reduce possible miscalculation by Moscow. To manage the transition to defense, policy guidance to address these challenges will have to be somewhat flexible; it will likely evolve over time, based on the evolution of the system as well as operational experience and future testing using varied assumptions and scenarios. ********** If all goes according to plan, by the end of 2004, the United States will deploy eight ground-based midcourse defense (GMD) interceptors (1) in Alaska and California, along with land-, sea-, and space-based sensors and the command and control systems to support the interceptors. By the end of 2005, 12 more GMD interceptors will be added, along with additional sensors and interceptor missiles on Navy ships. The initial deployments of 2004-2005 are only the first step on the path to the Bush administration goal of an integrated, global missile defense (2) to protect the United States, its friends and allies, and deployed forces against limited attacks by ballistic missiles of all ranges (short-, medium-, intermediate-, and long-range) in all phases of flight (boost, midcourse, and terminal). (3) The main concern driving this goal is not the ballistic missiles of major powers such as Russia but the proliferation of weapons of mass destruction (WMD) and ballistic missiles--particularly for rogue states such as North Korea and Iran. The program, however, is not tied to country-specific threats; instead, it takes a capabilities-based approach that "focuses more on how an adversary might fight than who the adversary might be and where a war might occur." (4) This means, as the director of the Missile Defense Agency (MDA) observed: We have to consider a wide range of missile threats posed by a long list of potential adversaries. And those threats are constantly changing and unpredictable.... A capability-based approach relies on continuing and comprehensive assessments of the threat, available technology, and what can be built to do an acceptable job, and does not accommodate a hard requirement that may not be appropriate. (5) Thus, there is no final architecture. Under the current plan, the missile defense program will proceed in 2-year block increments of spiral development. (6) For the most part, the Bush administration has been careful not to oversell the initial defensive capabilities so that expectations do not exceed reality. Officials have characterized the first deployments as "very basic" and a "nascent defensive system." (7) Secretary of Defense Donald Rumsfeld called it a "capability with a small 'c'" (to distinguish it from a formal initial operational capability) that "will probably, one would hope, improve as you go along. …

Molecular (mitochondrial DNA, isozyme) and morphological diversity of freshwater mussels (Family Hyriidae) was examined at 21 sites encompassing four large river systems, across southwest Queensland, Australia. Evidence was found for two major morphological groups. One group, which occurred in every river system, closely matched a recognized species (Velesunio ambiguus) both morphologically and in a well-supported lineage within a mitochondrial phylogeny generated from partial cytochrome c oxidase subunit I (COI) sequences. The second group most closely matched Velesunio wilsonii in shell morphology but formed three deeply divergent mitochondrial DNA lineages. All four lineages occurred sympatrically in some areas and displayed corresponding fixed differences at nuclear allozyme loci, which suggests an absence of recent hybridization and the presence of separate species.

The flow regime is regarded by many aquatic ecologists to be the key driver of river and floodplain wet- land ecosystems. We have focused this literature review around four key principles to highlight the important mech- anisms that link hydrology and aquatic biodiversity and to illustrate the consequent impacts of altered flow regimes: Firstly, flow is a major determinant of physical habitat in streams, which in turn is a major determinant of biotic com- position; Secondly, aquatic species have evolved life history strategies primarily in direct response to the natural flow regimes; Thirdly, maintenance of natural patterns of longitu- dinal and lateral connectivity is essential to the viability of populations of many riverine species; Finally, the invasion and success of exotic and introduced species in rivers is facilitated by the alteration of flow regimes. The impacts of flow change are manifest across broad taxonomic groups including riverine plants, invertebrates, and fish. Despite growing recognition of these relationships, ecologists still struggle to predict and quantify biotic responses to altered flow regimes. One obvious difficulty is the ability to distin- guish the direct effects of modified flow regimes from im- pacts associated with land-use change that often accom- panies water resource development. Currently, evidence about how rivers function in relation to flow regime and the flows that aquatic organisms need exists largely as a series of untested hypotheses. To overcome these problems, aquatic science needs to move quickly into a manipulative or experimental phase, preferably with the aims of restora- tion and measuring ecosystem response.

Somatic embryos were used to develop a cryopreservation protocol for Macropidia fuliginosa, a commercially-important species endemic to the south-west of Western Australia. Somatic embryos were allowed to develop from embryogenic callus for three weeks on an kinetin medium prior to processing. These were transferred and cultured on a agar solidified basal medium supplemented with 0 to 0.6 M sorbitol for 2 d prior to incubation in Plant Vitrification Solution Two (PVS2). Following this, embryos were then washed in 1 M sucrose solution (treated controls) or cooled in liquid nitrogen (LN). Cooled embryos were then warmed and washed in sucrose solution. Highest survival for cooled treatments (67.3%) was achieved by preculture with 0.4 M sorbitol, then incubation in PVS2. Further experimentation varying pre-culture duration (2 or 3 d) and incubation on either glycerol (0.8 M) or sorbitol (0.4 M) indicated that very high survival (90.6%) of embryos was achievable by adopting a 2 d preculture period on 0.8 M glycerol. The phenotype and growth rates of plants obtained using this protocol were similar to those of parent plants. This optimised procedure was then applied to tissue culture-derived shoot apices of the same clone also resulting in a high survival rate (84.4%).

Studies on the effects of plant growth regulators (PGRs) on survival, recovery and post-recovery growth of shoot apices following cryopreservation are limited. In this study, the effects of plant growth regulators in both the culture phase and the recovery phase of cryostorage were examined for the rare plant species, Anigozanthos viridis ssp terraspectans Hopper. Survival of shoot apices was not correlated to cytokinin or auxin treatments administered in culture media prior to cryostorage. In recovery media, the plant growth regulators, kinetin, zeatin (cytokinins), IAA, (auxin) and GA3 were examined for their effect following cryopreservation. It was found that the application of a combination of cytokinin and 0.5 microM GA3 from day zero was the most appropriate for obtaining vigorously growing plantlets following LN immersion. This combination proved to be more effective than basal medium, zeatin or kinetin treatments.

Providing flows for biota and environmental processes is a challenging water management issue. For society the ability and willingness to allocate water to sustain the environment is increasingly competitive due to escalating demand and as a consequence of climate change. In response, an array of environmental flow (E-flow) methods have developed. Our view is that few E-flows have been implemented and even fewer evaluated in a research and management context. Much of our science effort in E-flows has been directed primarily at method development, with less attention being given to monitoring, evaluation and subsequent revision of E-flow strategies. Our objectives are to highlight the lack of connection between current trends in E-flow literature and theory with assessment of the efficacy and practical application of these methods. Specifically, effective E-flows need to be explicit about flow-ecology relationships to adequately determine the amount and timing of water required. We briefly outline the historical development of E-flows and discuss how serial development of methods and techniques has restricted implementation, evaluation and revision. We highlight areas where methods are lacking, such as incorporation of data on flow-ecology relationships into operational use of E-flow methods. We suggest four initial steps that will improve the applicability, implementation and ultimate success of E-flows.

During the Cold War, strategic capabilities were synonymous with nuclear capabilities, and U.S. strategic planning focused on nuclear deterrence and response against a single adversary. Today, more potential enemies are developing asymmetric capabilities to inhibit or prevent U.S. military intervention in regional conflicts-in short, to wage strategic warfare by implicitly or explicitly threatening high- value political, military, or economic targets with weapons of mass destruction and disruption. U.S. security over the next several decades will depend increasingly on the ability to deter and respond effectively to strategic regional conflicts with significant escalation potential. The Department of Defense faces the task of ensuring that a comprehensive set of responses is developed for the National Command Authorities and is incorporated into planning before a conflict begins. To meet this challenge, the defense establishment should analyze requirements for deterring and combating strategic warfare in regional conflicts, identify shortcomings in plans and capabilities, and develop solutions. Providing a broad mix of military options could require changes in operational concepts, contingency planning, training, and resource allocation. The effort will require significant input from all the relevant commands and force providers, as well as the Office of the Secretary of Defense, Joint Staff, services, and other agencies.

Recent studies of the genetic structure of stream-dwelling organisms have suggested that fine-scale patterns are the consequence of patchy recruitment from a small number of matings and limited in-stream dispersal. Predictions of this hypothesis were tested by spatial and temporal analysis of the genetic structure of populations of a stream mayfly (Bungona sp.: Baetidae) in subtropical streams in south-eastern Queensland. Significant departures from Hardy–Weinberg proportions occurred more often than would be predicted by chance alone and no consistent pattern was observed across sites, loci or sampling times. As in previous studies, the largest differentiation was observed at the smallest spatial scale (reaches within streams) on most sampling occasions. These data provide additional support for a patchy recruitment hypothesis. Despite the fine-scale population structure, there was evidence of widespread adult dispersal across the study region, especially between streams and subcatchments within the same block of continuous dense forest.