7 resultados para Ère victorienne

em Plymouth Marine Science Electronic Archive (PlyMSEA)


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Information on past trends is essential to inform future predictions and underpin attribution needed to drive policy responses. It has long been recognised that sustained observations are essential for disentangling climate-driven change from other regional and local-scale anthropogenic impacts and environmental fluctuations or cycles in natural systems. This paper highlights how data rescue and re-use have contributed to the debate on climate change responses of marine biodiversity and ecosystems. It also illustrates via two case studies the re-use of old data to address new policy concerns. The case studies focus on (1) plankton, fish and benthos from the Western English Channel and (2) broad-scale and long-term studies of intertidal species around the British Isles. Case study 1 using the Marine Biological Association of the UK's English Channel data has shown the influence of climatic fluctuations on phenology (migration and breeding patterns) and has also helped to disentangle responses to fishing pressure from those driven by climate, and provided insights into ecosystem-level change in the English Channel. Case study 2 has shown recent range extensions, increases of abundance and changes in phenology (breeding patterns) of southern, warm-water intertidal species in relation to recent rapid climate change and fluctuations in northern and southern barnacle species, enabling modelling and prediction of future states. The case is made for continuing targeted sustained observations and their importance for marine management and policy development.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The resolution of the SSU rRNA gene for phylogenetic analysis in the diatoms has been evaluated by Theriot et al. who claimed that the SSU rRNA gene could not be used to resolve the monophyly of the three diatoms classes described by Medlin and Kaczmarska. Although they used both only bolidomonads and heterokonts as outgroups, they did not explore outgroups further away than the heterokonts. In this study, the use of the multiple outgroups inside and outside the heterokonts with the rRNA gene for recovering the three monophyletic clades at the class level is evaluated. Trees with multiple outgroups ranging from only bolidophytes to Bacteria and Archea were analyzed with Bayesian and Maximum Likelihood analyses and two data sets were recovered with the classes being monophyletic. Other data sets were analyzed with non-weighted and weighted maximum parsimony. The latter reduced the number of clades and lengthened branch lengths between the clades. One data set using a weighted analysis recovered the three classes as monophyletic. Taking only bolidophytes as the only outgroup never produced monophyletic clades. Multiple outgroups including many heterokonts and certain members of the crown group radiation recovered monophyletic clades. The three classes can be defined by clear morphological differences primarily based on auxospore ontogeny and envelope structure, the presence or absence of a structure (tube process or sternum) associated with the annulus and the location of the cribrum in those genera with loculate areolae. A cladistic analysis of some of these features is presented and recovers the three classes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Current knowledge about the spread of pathogens in aquatic environments is scarce probably because bacteria, viruses, algae and their toxins tend to occur at low concentrations in water, making them very difficult to measure directly. The purpose of this study was the development and validation of tools to detect pathogens in freshwater systems close to an urban area. In order to evaluate anthropogenic impacts on water microbiological quality, a phylogenetic microarray was developed in the context of the EU project µAQUA to detect simultaneously numerous pathogens and applied to samples from two different locations close to an urban area located upstream and downstream of Rome in the Tiber River. Furthermore, human enteric viruses were also detected. Fifty liters of water were collected and concentrated using a hollow-fiber ultrafiltration approach. The resultant concentrate was further size-fractionated through a series of decreasing pore size filters. RNA was extracted from pooled filters and hybridized to the newly designed microarray to detect pathogenic bacteria, protozoa and toxic cyanobacteria. Diatoms as indicators of the water quality status, were also included in the microarray to evaluate water quality. The microarray results gave positive signals for bacteria, diatoms, cyanobacteria and protozoa. Cross validation of the microarray was performed using standard microbiological methods for the bacteria. The presence of oral-fecal transmitted human enteric-viruses were detected using q-PCR. Significant concentrations of Salmonella, Clostridium, Campylobacter and Staphylococcus as well as Hepatitis E Virus (HEV), noroviruses GI (NoGGI) and GII (NoGII) and human adenovirus 41 (ADV 41) were found in the Mezzocammino site, whereas lower concentrations of other bacteria and only the ADV41 virus was recovered at the Castel Giubileo site. This study revealed that the pollution level in the Tiber River was considerably higher downstream rather than upstream of Rome and the downstream location was contaminated by emerging and re-emerging pathogens.