Microbial community dynamics in the two-stage anaerobic digestion process of two-phase olive mill residue

The microbial communities in a two-stage anaerobic digestion process treating olive mill “solid” residues were studied by molecular identification techniques. The microbial species identification in the hydrolytic-acidogenic step and in the methanogenic step was carried out by polymerase chain reaction amplification of 16S ribosomal RNA genes, denaturing gradient gel electrophoresis, cloning, and sequencing. This study revealed that Firmicutes (from 31.1 to 61.1 %, average 42.1 %) mainly represented by Clostridiales, and the Chloroflexi (from 29.4 to 53.3 %, average 47.35 %) were the most abundant species for the hydrolytic-acidogenic reactor. Other microorganisms such as Gamma-Proteobacteria (Pseudomonas species as the major representative; from 3.9 to 9.7 %; average 5.7 %), Actinobacteria (from 1.0 to 10.2 %; average 4.6 %) and Bacteroidetes (from 1.1 to 3.1 %; average 1.7 %) were also detected. The methanogenic communities detected in the methanogenic reactor were mainly represented by members of the obligate acetotrophic methanogenic genus Methanosaeta. Methanosaeta was the crucial Archaea to obtain a high methane yield in the methanogenic stage.     

Overview of integrative tools and methods in assessing ecological integrity in estuarine and coastal systems worldwide

In recent years, several sets of legislation worldwide (Oceans Act in USA, Australia or Canada; Water Framework Directive or Marine Strategy in Europe, National Water Act in South Africa, etc.) have been developed in order to address ecological quality or integrity, within estuarine and coastal systems. Most such legislation seeks to define quality in an integrative way, by using several biological elements, together with physico-chemical and pollution elements. Such an approach allows assessment of ecological status at the ecosystem level ('ecosystem approach' or 'holistic approach' methodologies), rather than at species level (e.g. mussel biomonitoring or Mussel Watch) or just at chemical level (i.e. quality objectives) alone. Increasing attention has been paid to the development of tools for different physico-chemical or biological (phytoplankton, zooplankton, benthos, algae, phanerogams, fishes) elements of the ecosystems. However, few methodologies integrate all the elements into a single evaluation of a water body. The need for such integrative tools to assess ecosystem quality is very important, both from a scientific and stakeholder point of view. Politicians and managers need information from simple and pragmatic, but scientifically sound methodologies, in order to show to society the evolution of a zone (estuary, coastal area, etc.), taking into account human pressures or recovery processes. These approaches include: (i) multidisciplinarity, inherent in the teams involved in their implementation; (ii) integration of biotic and abiotic factors; (iii) accurate and validated methods in determining ecological integrity; and (iv) adequate indicators to follow the evolution of the monitored ecosystems. While some countries increasingly use the establishment of marine parks to conserve marine biodiversity and ecological integrity, there is awareness (e.g. in Australia) that conservation and management of marine ecosystems cannot be restricted to Marine Protected Areas but must include areas outside such reserves. This contribution reviews the current situation of integrative ecological assessment worldwide, by presenting several examples from each of the continents: Africa, Asia, Australia, Europe and North America.     

Development and deployment of a stable tow body

With the introduction of improved underwater transducers, there is a need for a stable tow body for oceanographic measurements. This paper summarizes the development of a 260 kg, 1.83×1.06×0.81 m tow body. It covers the performance requirements, the tow body design and manufacture as well as its tow trials off of Biloxi, Mississippi aboard the R.V. Tommy Munro.     

Response of single benthic metrics and multi-metric methods to anthropogenic pressure gradients, in five distinct European coastal and transitional ecosystems

In recent times many benthic indices have been proposed to assess the ecological quality of marine waters worldwide. In this study we compared single metrics and multi-metric methods to assess coastal and transitional benthic status along human pressure gradients in five distinct environments across Europe: Varna bay and lake (Bulgaria), Lesina lagoon (Italy), Mondego estuary (Portugal), Basque coast (Spain) and Oslofjord (Norway). Hence, 13 single metrics (abundance, number of taxa, and several diversity and sensitivity indices) and eight of the most common indices used within the European Water Framework Directive (WFD) for benthic assessment were selected: index of size spectra (ISS), Benthic assessment tool (BAT), Norwegian quality index (NQI), Multivariate AMBI (M-AMBI), Benthic quality index (BQI), (Benthic ecosystem quality index (BEQI), Benthic index based on taxonomic sufficiency (BITS), and infaunal quality index (IQI). Within each system, sampling sites were ordered in an increasing pressure gradient according to a preliminary classification based on professional judgement. The different indices are largely consistent in their response to pressure gradient, except in some particular cases (i.e. BITS, in all cases, or ISS when a low number of individuals is present). Inconsistencies between indicator responses were most pronounced in transitional waters (i.e. IQI, BEQI), highlighting the difficulties of the generic application of indicators to all marine, estuarine and lagoonal environments. However, some of the single (i.e. ecological groups approach, diversity, richness) and multi-metric methods (i.e. BAT, M-AMBI, NQI) were able to detect such gradients both in transitional and coastal environments, being these multi-metric methods more consistent in the detection than single indices. This study highlights the importance of survey design and good reference conditions for some indicators. The agreement observed between different methodologies and their ability to detect quality trends across distinct environments constitutes a promising result for the implementation of the WFD’s monitoring plans. Moreover, these results have management implications, regarding the dangers of misclassification, uncertainty in the assessment, use of conflicting indices, and testing and validation of indices.     

Wave resistance for high-speed catamarans

The object of this study was to investigate the wave resistance component for high-speed catamarans. Two methods were applied: the slender-body theory proposed by Michell [Philos. Mag. 45(5) (1898) 106] and a 3D method used by Shipflow^™ (FLOWTECH, Shipflow^™ 2.4, User Manual, 1988) software.Results were obtained for different types of twin hulls and attention was given to the effects of catamaran hull spacing.The study also included the effects of shallow water on the wave resistance component.Special attention was given to the height of waves generated by the craft to ascertain effects on river banks.     

Calculation of hydrofoil craft take-off speed including influence of foil size, foil angle and propeller shaft angle

The sensitivity of the hydrofoil take-off speed to changes in foil size and angle has not been well documented. This paper first presents the verification of the UNO-HYF1 with published performance data. Following the satisfactory validation, the results are presented in hydrofoil take-off to show the change with speed when the foil area, foil angle and propeller shaft angle are changed. The calculations indicate that varying the hydrofoil area has the largest impact on hydrofoil take-off speed.     

Kinematics of the Dadeldhura klippe shear zones (W Nepal): implications for the foreland evolution of the Himalayan metamorphic core

Mapping combined with structural analyses in the foreland edge of the metamorphic core of the Himalayas in SW Nepal highlights the existence of two north‐dipping shear zones with opposite sense of shear. Here, the metamorphic core is mainly affected by non‐coaxial top‐to‐the‐south sense of shear at temperatures between 450 °C and 550 °C that switch to a top‐to‐the‐north sense of shear at the top of the metamorphic core. We regionally correlate this upper shear zone with the South Tibetan detachment system. Ar‐dating on white mica indicates that both shear zones operated between 23 Ma and 17 Ma. Restoration of the folded South Tibetan detachment in far western Nepal yields a minimum dip‐slip distance of 190 km, compatible with predictions made by models of extrusion of a weak mid‐crustal channel. Our results support an orogenic model in which channel flow in the hinterland coexisted with thrust wedge mechanics in the foreland.