A fast Bayesian method for updating and forecasting hourly ozone levels

A Bayesian hierarchical space-time model is proposed by combining information from real-time ambient AIRNow air monitoring data, and output from a computer simulation model known as the Community Multi-scale Air Quality (Eta-CMAQ) forecast model. A model validation analysis shows that the model predicted maps are more accurate than the maps based solely on the Eta-CMAQ forecast data for a 2 week test period. These out-of sample spatial predictions and temporal forecasts also outperform those from regression models with independent Gaussian errors. The method is fully Bayesian and is able to instantly update the map for the current hour (upon receiving monitor data for the current hour) and forecast the map for several hours ahead. In particular, the 8 h average map which is the average of the past 4 h, current hour and 3 h ahead is instantly obtained at the current hour. Based on our validation, the exact Bayesian method is preferable to more complex models in a real-time updating and forecasting environment.     

First ceratosaurian dinosaur from Australia

The basal theropod dinosaur clade Ceratosauria, and its subclade Abelisauroidea, is characteristic of late Mesozoic terrestrial vertebrate faunas in western Gondwana (South America, Africa, Madagascar, and India) and Europe. Yet unambiguous records of ceratosaurs have hitherto been absent from Australia, where the theropod assemblage appears to include several typically Laurasian clades. Here, we report the first evidence of ceratosaurs (and potentially abelisauroids) from eastern Gondwana––a diagnostic astragalocalcaneum from the Aptian (121–125?Ma) of Victoria, Australia. Ceratosauria thus occurred in both western and eastern Gondwana during the Early Cretaceous. This fossil adds to the poorly known dinosaur fauna of Australia, a major clade of basal theropods, emphasising that its mid-Cretaceous theropod diversity was surprisingly cosmopolitan despite relative geographic isolation, including clades that have been thought to be typical of both Gondwana and Laurasia––Ceratosauria, Spinosauridae, Carcharodontosauria, Tyrannosauroidea, and Deinonychosauria. Such a contemporaneous association of theropod clades is unknown from other Gondwanan continents and questions the views that the late Mesozoic dinosaur fauna of Australia was dominated by Gondwanan or Laurasian elements, extreme isolation, relictualism, and/or novelty as a ‘centre of origin’. The cosmopolitan theropod fauna of Australia probably reflects the global distribution of these clades early in their history, prior to significant continental breakup.     

Dioxins and polychlorinated biphenyls (PCDD/Fs and PCBs) in food from farms close to foot and mouth disease animal pyres

To control the outbreak of foot and mouth disease, which occurred in the UK in early 2001, a large number of farm animals were slaughtered. Where it was not possible to render or landfill the carcasses, they were destroyed by burning on open pyres, with wood, coal and other materials. Uncontrolled combustion such as this is known to produce small quantities of dioxins and an investigation was made into whether, as a result of the burning, there was an elevation in the concentrations of these compounds in food produced in the areas close to the pyres. With few exceptions, concentrations of PCDD/Fs and PCBs were within the expected ranges as predicted by reference data. No accumulation over time was evident from a repeat milk sampling exercise. Where elevated concentrations of PCDD/Fs and PCBs were found in chickens and eggs, they were in samples not destined for the food chain. Elevated levels in some samples of milk from Dumfries and Galloway were not found in earlier or later samples and may have been found as a result of a temporary feeding regime. Elevated concentrations in lamb from Carmarthenshire were from very young animals which would not have entered the food chain. There was no evidence of any significant increase in dietary exposure to PCDD/Fs and PCBs as a result of the FMD pyres.     

Initial results from a multi-institutional collaboration to monitor harmful algal blooms in South Carolina

The rapid rate of development in the South Carolina (SC) coastal zone has heightened public concern for the condition of the state's estuaries, and alerted scientists to the potential that novel and adverse effects on estuarine ecosystems may result. Although well-developed databases from long-term monitoring programs exist for many variables valuable in predicting and following system responses, information on phytoplankton distributions in SC estuaries has lagged. Knowledge of the dynamical relationship between environmental (e.g., nutrient quantity and quality) and biological (e.g., grazing) regulation, and phytoplankton biomass and composition is critical to understanding estuarine susceptibility to eutrophication or harmful algal blooms (HABs). Recently, SC scientists from federal, state, and academic institutions established a collaborative monitoring program to assess HAB distribution and ecology statewide. The South Carolina Harmful Algal Bloom Program includes: a) intensive temporal monitoring at areas of known HAB occurrence or those exhibiting symptoms potentially related to HABs (e.g., prevalent fish lesions), b) extensive spatial monitoring in coordination with existing statewide efforts, c) a citizen volunteer monitoring network, d) nutrient response bioassays, and e) laboratory-based physiological experiments on HAB isolates. By combining trip-wire surveillance and rapid response systems, routine monitoring of environmental parameters and HAB distribution, and process-oriented studies examining the physiological functioning of HAB species, an enhanced understanding of the impact and environmental control of HABs in SC estuaries will be achieved. The application of this approach to studies on the distribution and physiological ecology of a new widespread SC red tide, and to the discovery of several potentially toxic blooms (including Pfiesteria) in SC holding ponds, are described.     

Inheritance of a nuclear DNA polymorphism assayed in single bivalve larvae

We examined the inheritance of theMytilus edulis CaM-1 Intron 3 locus, a non-coding DNA locus with two potentially neutral length-variants. The polymerase chain reaction (PCR) was used to determine theCaM-1 genotype for 799 larvae obtained from 11 laboratory crosses. Larvae were typed singly only 8 to 24 h after fertilization. We find evidence that each allele can be inherited from either sex, that there are no barriers to fertilization between gametes of different genotypes, and that most larvae have genotypes compatible with Mendelian inheritance of the locus. Deviations from expected genotype frequencies were found in some crosses; we suggest that a contributing factor is aneuploidy in early larvae, but a major cause is more likely to be selection at a locus linked toCaM-1, occurring under the artificial laboratory culture conditions. This study demonstrates the feasibility of applying molecular genetic techniques to early larval stages of marine bivalves, and presents a new non-destructive biopsy method for DNA analysis from living adult mussels.     

Intron-targeted PCR: a new approach to survey neutral DNA polymorphism in bivalve populations

PCR (polymerase chain reaction) amplification of non-coding introns in phylogenetically widespread genes, using DNA primers based on the conserved exon sequences, provides a widely applicable strategy for finding DNA polymorphisms in eukaryotic genomes. Polymorphisms in introns provide a new source of potentially neurtral genetic markers for use in population biology. Here we use this approach to design PCR primers for an intron of calmodulin genes. We show that there are at least two calmodulin genes in mussels of theMytilus edulis species complex, and using gene- and species-specific primers we resolve two alleles at a calmodulin intron locus. Population surveys using PcR of adult mussel DNA reveal that genotype frequencies at most sites surveyed in England, Scotland and Italy, conform to Hardy-Weinberg equilibrium, suggesting that this is a novel neutral genetic marker. The data also provide preliminary evidence for restricted gene flow between mussel populations on the west and northeast coasts of Britain, and for local effects around the Thames estuary.     

Horses and cows might teach us about human knees

Our comparative study of the knees of horses and cows (paraphrased as highly evolved joggers and as domesticated couch-potatoes, respectively) demonstrates significant differences in the posterior sections of bovine and equine tibial cartilage, which are consistent with specialisation for gait. These insights were possible using a novel analytical measuring technique based on the shearing of small biopsy samples, called dynamic shear analysis. We assert that this technique could provide a powerful new tool to precisely quantify the pathology of osteoarthritis for the medical field.     

Density-mediated, context-dependent consumer-resource interactions between ants and extrafloral nectar plants

Interspecific interactions are often mediated by the interplay between resource supply and consumer density. The supply of a resource and a consumer's density response to it may in turn yield context-dependent use of other resources. Such consumer-resource interactions occur not only for predator-prey and competitive interactions, but for mutualistic ones as well. For example, consumer-resource interactions between ants and extrafloral nectar (EFN) plants are often mutualistic, as EFN resources attract and reward ants which protect plants from herbivory. Yet, ants also commonly exploit floral resources, leading to antagonistic consumer-resource interactions by disrupting pollination and plant reproduction. EFN resources associated with mutualistic ant-plant interactions may also mediate antagonistic ant-flower interactions through the aggregative density response of ants on plants, which could either exacerbate ant-flower interactions or alternatively satiate and distract ants from floral resources. In this study, we examined how EFN resources mediate the density response of ants on senita cacti in the Sonoran Desert and their context-dependent use of floral resources. Removal of EFN resources reduced the aggregative density of ants on plants, both on hourly and daily time scales. Yet, the increased aggregative ant density on plants with EFN resources decreased rather than increased ant use of floral resources, including contacts with and time spent in flowers. Behavioral assays showed no confounding effect of floral deterrents on ant-flower interactions. Thus, ant use of floral resources depends on the supply of EFN resources, which mediates the potential for both mutualistic and antagonistic interactions by increasing the aggregative density of ants protecting plants, while concurrently distracting ants from floral resources. Nevertheless, only certain years and populations of study showed an increase in plant reproduction through herbivore protection or ant distraction from floral resources. Despite pronounced effects of EFN resources mediating the aggregative density of ants on plants and their context-dependent use of floral resources, consumer-resource interactions remained largely commensalistic.     

Spatial dynamics and substrate impacts of recreational snorkelers and SCUBA divers in Hawaiian Marine Protected Areas

We quantified spatial dynamics and substrate impacts of snorkelers and SCUBA divers within four Hawaiian MPAs to determine: (1) whether coral reefs in these areas are being damaged by recreational activities, and (2) how damage might be mitigated. Observers secretly followed snorkelers and SCUBA divers, and used handheld Global Positioning System (GPS) units to record their geographic tracks and substrate contacts. Most activities occurred within relatively small, well-defined areas associated with access points. Despite heavy use, recreation impact was low at Hawaiian MPAs because most fragile corals occurred below the maximum depth of the dominant recreational activity (snorkeling). SCUBA diving was only common at one MPA with physically durable benthic habitats. GPS tracking provided useful insights into how recreational impacts to MPAs could be reduced. General topography could be used to predict where visitors will go, and designated access points could be used to focus substrate contact away from fragile habitats.     

Ecological and evolutionary mechanisms for low seed: ovule ratios: need for a pluralistic approach?

Central to the ecology and evolution of a broad range of plants is understanding why they routinely have submaximal reproduction manifested as low seed : ovule and fruit : flower ratios. We know much less about the processes responsible for low seed : ovule ratios than we do for fruit : flower ratios. Current hypotheses for low seed : ovule ratios are largely drawn from those for fruit : flower ratios, including proximate (ecological) causes of pollen limitation, resource limitation, and pollen quality, as well as the ultimate (evolutionary) hypothesis of "bet hedging" on stochastic pollination. Yet, such mechanisms operating on fruit : flower ratios at the whole-plant level may not best explain low seed : ovule ratios at the individual-flower level. We tested each of these proximate and ultimate causes for low seed : ovule ratios using the specialized pollination mutualism between senita cacti (Pachycereus schottii) and senita moths (Upiga virescens). Seed : ovule ratios were consistently low (approximately 0.61). Such excess ovule production by senita likely has a strong genetic component given the significant differences among plants in ovule number and the consistency in ovule production by plants within and among flowering seasons. Excess ovule production and low seed : ovule ratios could not be explained by pollen limitation, resource limitation, pollen quality, or bet hedging. Nevertheless, phenotypic selection analyses did show significant selection gradients for increased ovule number, suggesting that other evolutionary processes may be responsible for excess ovule production and low seed : ovule ratios. In contrast, low fruit : flower ratios at the whole-plant level were explained by an apparent equilibrium between pollen and resource limitation. Thus, mechanisms responsible for low fruit : flower ratios at the whole-plant level are not necessarily in accord with those of low seed : ovule ratios at the individual-flower level. This suggests that we may need to adopt a more pluralistic approach to seed : ovule ratios and consider alternative hypotheses, including a greater array of proximate and ultimate causes. Initial results of this study suggest that floral allometry, selection on correlated floral traits, stigma clogging with pollen grains, and style clogging with pollen tubes may provide promising avenues for understanding low seed : ovule ratios.