Consciousness below SCUBA depths

The Order Enoplida (Phylum Nematoda) has been proposed as a divergent nematode lineage—Enoplid nematodes are thought to exhibit morphological and developmental characteristics present in the ‘ancestral nematode’. However, previous molecular phylogenies have failed to unequivocally confirm the position of this group. The Enoplida is primarily comprised of free-living marine species; if these taxa represent close relatives of the nematode ancestor, this relationship would presumably imply a marine origin for the phylum. Prior to this investigation, few publically available gene sequences existed for Enoplid nematodes, and published sequences represented only shallow water fauna from Northwest Europe. This study has aimed to improve resolution at the base of the nematode tree, using drastically increased taxon-sampling within the previously neglected Enoplid clade. Morphological identifications, nuclear gene sequences (18S and 28S rRNA), and mitochondrial gene sequences (Cox1) were obtained from marine specimens representing a variety of deep-sea and intertidal habitats. Molecular data were used to assess the phylogenetic placement of the Enoplid clade, resolve internal taxonomic relationships within this group, and investigate relationships between shallow water and deep-sea fauna. Despite rigorous empirical testing and comprehensive taxon sampling, large-scale phylogenetic analyses based on 18S rRNA sequences (using both Maximum Likelihood and Bayesian Inference methods) failed to provide added resolution at the base of the nematode tree. Molecular data from the 18S rRNA gene was unable to confirm the placement of Enoplida as a divergent lineage representing the sister taxon to all other nematodes. These findings highlight the limitations of the 18S gene for resolving the deepest evolutionary splits amongst nematode clades. Analysis of internal relationships reveals that the Enoplida is split into two main clades, with groups consisting of terrestrial and primarily marine fauna, respectively. For marine taxa, deep-sea and shallow-water specimens from the same genus consistently appear as sister taxa. Deep-sea nematode species may have arisen via several evolutionary routes; some deep-sea clades appear to represent recently derived forms, while other groups seem to have radiated much earlier. Nematodes from deep-sea sites exhibit no obvious clustering according to depth or geographic location, and specimens represent a wide taxonomic range within the Enoplida. In addition, there seems to be some molecular evidence for purportedly cosmopolitan nematode species; identical gene sequences were recorded between distant shallow water locations, as well as between deep-sea and shallow water habitats. Data from Enoplid nematodes suggests an intriguing pattern for nematode species distributions—validating these preliminary insights will require a large amount of molecular data from many additional geographic locations. Future studies will also need to incorporate data from additional genetic loci (or use phylogenomic methods) in order to build robust deep phylogenies.

Reef proliferation and carbonate platform expansion took place during the Late Triassic. These major trends are mainly documented in the Tethys realm. The main goal of this study is to improve our understanding of mid-oceanic carbonate platforms of the West Panthalassa during the Late Triassic. Special focus is given to the shallow water depositional settings and to the ecological structure and evolution of reef ecosystems. We investigate Upper Triassic carbonates of the Sambosan Accretionary Complex in Southwest Japan. Detailed microfacies analysis has been carried out on thin sections from twenty four localities at Kyushu Island, Shikoku Island and Honshu Island. Our results highlight the evolution of mid-oceanic shallow water environments of the West Panthalassa domain during the Late Triassic and refine the correlation of the Sambosan limestone with coeval shallow water carbonates of the Tethys and East Panthalassa domain. This work provides valuable data to improve Early Mesozoic paleogeographic reconstructions.

Vertical distribution, composition and migratory patterns of acoustic scattering layers in the Canary Islands

It is generally considered that a significant change in oceanic redox conditions occurred during the Ediacaran-Cambrian transition. However, there are currently two major conflicting views on the degree of oxygenation of deep water (oxic vs. ferruginous) during this interval. To date, the oxygenation conditions of the Early Cambrian ocean have not been well constrained. The oxygenation magnitude and mechanism of the Early Cambrian ocean could be critical to the significant biological evolution of the "Cambrian Explosion". To constrain the Early Cambrian oceanic redox environment, we conducted an integrated study on iron and sulfur isotopes and redox-sensitive elements (Mo, U, and V) of Lower Cambrian phosphorite deposits from two shallow sections (Meishucun and Gezhongwu) and a deeper water section (Zunyi) from the Yangtze Platform, South China. The near zero δ 56 Fe values from the two shallow sections studied here reflect oxic conditions in the lower phosphorite deposition. An obvious positive shift in δ 56 Fe and redox-sensitive element content was observed in the middle parts of the two shallow water sections, which might reflect loss of light iron by dissimilatory iron reduction during early diagenesis under suboxic shallow water in the platform. However, the highly positive δ 56 Fe values in the deep section could reflect a lower oxidation degree of dissolved Fe(II) under anoxic deep water. The data suggest redox-stratified oceanic conditions during the Early Cambrian, in which completely oxygenated shallow water (platform) coexisted with anoxic deep water (slope). We propose that prolonged upwelling of dissolved organic carbon (DOC)-, Fe(II)- and phosphorus-rich anoxic deep water in a redox-stratified ocean could have increased exchange with the open ocean, resulting in major phosphorite deposition in oxic-suboxic conditions. The progressive oxygenation of the ocean may have facilitated the Early Cambrian biotic diversification.

The need for a replacement airport in Hong Kong has required the development of new road and rail links. Three sea crossings are involved and the longest requires a 1377 m suspension span to be known as the Tsing Ma bridge. Typhoon winds of 300 km/h are expected at the site and the structure has been designed to resist the static and dynamic effects of these. Six lanes of traffic and two tracks of high speed mass transit railway will be accommodated on the bridge. This has had a major effect on the articulation and detailing of the suspended structure. Brief details of the design are provided. At the Ma Wan end, the suspended sidespan is 355m, and the approach spans are 80m and 48m. At the Tsing Yi end, there is a straight backstay cable below which there are 4 approach spans, each 72m long. The navigation channel has a width measured along the bridge centre line of about 1070m, and a vertical headroom of 59.5m above high water is provided. The towers are of reinforced concrete. The legs of each tower incline towards each other at a slope of 1:100. Bracing between the legs takes the form of 4 rectangular post-tensioned portal beams. The Tsing Yi tower has been placed onshore to minimise the ship protection measures required. A rock filled island will protect the Ma Wan tower, which is located in shallow water. The main cables are constructed from preformed parallel wire strands. The cable anchorage on the Ma Wan side is of concrete gravity construction. On the Tsing Yi side, each cable terminates in a tunnel anchorage. The French title of this article is: Evolution de l'etude du pont Tsing Ma. The German title of this article is: Entwurfsprozess der Tsing-Ma Bruecke. For the covering abstract of the conference see IRRD 851274.

The first commercial use of ROV-deployed ocean bottom seismic nodes (OBN) was on the Cantarell/Sihil field offshore Mexico in 2003/4. The resulting data showed a clear uplift over that acquired previously using ocean bottom cable (OBC) equipment and was a forerunner to the extensive volume of OBN surveys that have been acquired worldwide in both deep water, using ROVs for deployment, and shallower water depths where both node-on-a-rope (NOAR) and node-on-a wire (NOAW) systems have been used employed. The move towards OBN and away from OBC has been driven by the desire to improve operational performance and hence reduce ocean bottom seismic (OBS) survey costs. The larger spread geometries enabled by higher node inventories reduce the traditional duplicated shot overhead implicit in the limited number of receivers historically available on an OBC crew, due to the inherent technical reliability limitations of connectors, terminations, data telemetry and power distribution. When coupled with recent advances in the data processing to de-blend so-called simultaneous sources, the resulting square kilometer rates for full azimuth/long offset OBN data are beginning to allow the technique to be considered for exploration in addition to the appraisal and development objectives that have traditionally been its focus. In this presentation the technical evolution of OBN will be briefly described, the key aspects for improving survey efficiency explained and the likely future direction and application, especially in both the shallow and deep water offshore Mexico, highlighted.

Over 10,000 bivalves were collected to investigate the microevolutionary patterns in the Peterborough Member of the Oxford Clay Formation. Two main bivalve lineages were studied Meleagrinella braamburiensis and Mesosaccella morrisi. M. braamburiensis was a thin-shelled suspension-feeder and M. morrisi was an infaunal deposit-feeder. These patterns were examined in the context of the new plus ca change model, which has extended the debate on microevolutionary patterns in the fossil record. The model proposes gradualism during narrowly fluctuating, relatively stable environments, and in contrast, net stasis in more unstable environments. The model also predicts for more gradualistic evolution on land in the tropics and in the deep sea, and for more stasis (and occasional punctuations) in shallow waters and temperate zones. Morphological patterns were detected from two distinctly different sets of environments within the Peterborough Member. The differences in environment were detected through lithological, palaeontological and geochemical evidence. It was found that a more stable period of environmental conditions occurred throughout the majority of the obductum Subzone of the Peterborough Member, whilst a period of more fluctuating environmental conditions (in terms of substrate, faunal composition, TOC, OI, carbonate carbon and total sulphur content) prevailed during the grossouvrei Subzone of the Peterborough Member. Bivalves were collected from three localities: Calvert landfill site, Buckinghamshire; Saxon and Orton brick pits, Peterborough. At Calvert and Saxon pits both the more stable environment and the more fluctuating environment, i.e. obductum and grossouvrei Subzones, were collected from. At Orton pit just the more stable environment, i.e. obductum Subzone, was collected from. Morphological patterns observed for the Length to Height ration for M. braamburiensis showed overall net stasis throughout the more stable environment at Calvert, Orton and Saxon pits, and throughout the more fluctuating environment at Calvert and Saxon pits. The Hinge Length to Anterior Length ratio for M. braamburiensis showed positive net morphological change throughout the more stable environment and net stasis throughout the more fluctuating environment at Calvert pit. Net stasis was observed throughout both the more stable and more fluctuating environments at Saxon pit, and was also observed throughout the more stable environment at Orton pit. Morphological patterns observed for the Length to Height ration for M. morrisi at Calvert and Saxon pits, showed the positive net morphological change throughout the more stable environment, with net stasis during the more fluctuation environment. The Hinge Length to Anterior Length ratio for M. morrisi showed positive net morphological change during the more stable environment, and net stasis during the more fluctuating environment at Calvert pit. Net stasis was observed throughout both the more stable and more fluctuating environments at Saxon pit. (M. morrisi was not studied at Orton pit). The morphological patterns observed, within the same species, obtained from the two separate geographically areas, are often distinctly different. Local microevolutionary changes or ecophenotypic variation are the two proposed alternatives for this difference. Overall, the morphological patterns observed from the two bivalve species within the Peterborough Member match, fairly closely, the plus ca change model's predictions for shallow marine invertebrates.

Although dike-break and dam-break processes have similar unsteady and discontinuous hydrodynamic characteristics, there are significant differences. In general, dam-break simulations focus on the flood discharge, whereas dike-break simulations are required to provide detailed information on the hydraulic and breach evolution processes, such as pit-scour and breach-expansion. In order to overcome the difficulties inherent in applying existing dam-break models to dike-breaks, this paper presents an integrated model that combines the shallow water, sediment transport, riverbed deformation and breach-expansion equations. A Godunov-type finite volume method is used for the flow simulation, based on a fixed quadtree grid system. The hydrodynamic aspects of the model are validated for an idealized rectangular dam break. A representative reach in the Yellow River is selected at a location where there is a significant risk of a dike-break, and full-scale topographic and hydrologic data are available. Typical dike-break processes are successfully simulated, with predicted hydraulic characteristics and terrain changes qualitatively in agreement with laboratory data. The modeling study is of practical importance for implementation of engineering countermeasures in the Yellow River, such as breach blocking and head wrapping.

Precambrian geology of the central Mazatzal Mountains, Arizona. Lead isotope heterogeneity in Precambrian igneous feldspars

This paper deals with the evolution of carbonate rocks and associated strata-bound depositsof various geological times in China. Distributions of the carbonate rocks are not very homo-geneous in time and space. Temporally, they are less common in both Archaean and Meso-Cainozoic strata, but more abundant in Palaeozoic and Proterozoic strata; spacially, they aremore abundant in the East Platform, but less in the West Folding Zone. They were depositedmainly in the sedimentary environments with shallow water. The Archaean carbonate rockswere formed by chemical processes, the Proterozoic carbonate rocks composed mainly of dolo-mites were deposited by algal activity, and the Palaeozoic and some Meso-Cainozoic carbonaterocks, in which limestones were predominant over dolomites, were formed by chemical and bio-chemical processes. After the Proterozoic era bioherms and banks were initiated. Many strata-bound deposits are found to associate with carbonate rocks in China,most of which were formed from the reformation caused by Hercynian and Yenshanian oro-genies.

O conceito de sistema petrolífero agrupa os diversos elementos que controlam a existência de jazidas de petróleo numa bacia sedimentar. Tal conceito, visualizado numa escala global, parece justificar de maneira adequada as diversas províncias petrolíferas conhecidas. A evolução tectono-sedimentar meso-cenozóica da margem continental brasileira propiciou o desenvolvimento desses elementos-chave, cuja presença é requisito fundamental a que uma determinada região seja atrativa para a prospecção petrolífera. Merece destaque nesse particular o segmento de águas profundas da Bacia de Campos, que, na visão contemporânea, representa a porção mais bem aquinhoada em termos de volumes descobertos de toda a margem brasileira. Em termos históricos, a exploração de petróleo no Brasil inclui três grandes fases: o período pré-Petrobras, basicamente de atividades pioneiras de reconhecimento; a etapa de exclusividade da Petrobras, onde se vislumbram quatro etapas - 1954/1968: Fase Terrestre, 1969/1974: Fase Marítima/Plataforma Rasa, 1975/1984: Fase Marítima/Plataforma Rasa/Bacia de Campos, e 1985/1997: Fase Marítima/Bacia de Campos/Águas Profundas, cada uma delas com características particulares e responsável por sucessivos incrementos na reserva petrolífera do País, que alcança hoje cerca de 16 bilhões de barris de óleo-equivalente; e a fase atual, sob a vigência da Nova Lei do Petróleo, caracterizada por intensa atividade em que várias companhias nacionais e estrangeiras atuam tanto em áreas anteriormente trabalhadas como em desafiadoras novas fronteiras.

The aim of the paper is numerical modeling of the shallow water equation with source terms by genuinely multdimensional finite volume evolution Galerkin schemes. The shallow water system, or its one-dimensional analogy the Saint-Venant equation, is used extensively for numerical simulation of natural rivers. Mathematically the shallow water system belongs to the class of balance laws. A special treatment of the source terms describing the bottom topography as well as frictions effects is necessary in order to reflect their balance with the gradients of fluxes. We present behaviour of our new well-balance FVEG scheme for several benchmark test problems and compare our results with those obtained by the finite element scheme of Teschke et al. used for practical river simulations.

Chapter 4 - One small step for amphibious fish, one evolutionary leap for moving tetrapods on Earth

Understanding the underlying mechanisms that have generated the striking biodiversity inhabiting deep-sea ecosystems remains a challenge in evolutionary biology. Here, we addressed this topic by studying the macroevolutionary dynamics that have shaped the diversification of squaliform sharks, an iconic clade of deep-sea vertebrates. Using phylogenetic comparative methods and fossil-based Bayesian diversification estimates, both at species level, we combined fossil record data with molecular phylogenies to provide a quantitative framework for understanding the evolutionary history of Squaliformes. We reveal that early squaliform lineages originated in shallow water during the Early Cretaceous and experienced multiple independent shifts toward the deep sea during the Late Cretaceous. Importantly, we show that these shifts were likely facilitated by the acquisition of bioluminescence, which significantly impacted body size evolution among squaliform lineages. Furthermore, deep-sea colonization events coincide with periods of climate warming and marine transgression at the Cenomanian-Turonian and Palaeocene-Eocene transitions. Following these colonizations, deep-sea squaliform lineages have diversified over the last 30 Myr, resulting in one of the richest deep-sea radiations in sharks. These results demonstrate how the complex interplay between key innovation and colonization of new habitats drove major ecological transition, highlighting the importance of an integrative framework when studying deep-time macroevolutionary dynamics.

This study presents a detailed analysis of late Miocene invertebrate fossil assemblages from the Aruwakkalu area of the North western coastal region in Sri Lanka, focusing on biostratigraphy and paleoenvironmental reconstruction. This investigation reveals diverse fossil taxa, such as bryozoans, corals, bivalves, and gastropods, providing insights into marine ecosystems. Bryozoans belonging to the class Gymnolaemata were identified in impure limestone layers, displaying sustained features such as sorus and autozooid structures. Coral fossils from the order Scleractinia were abundant in sandstone layers, highlighting the presence of colonial organisms indicative of coral reef environments. Bivalve fossils, predominantly from the families of Veneridae, Ostreidae, and Pectinidae, were found in various limestone layers, indicating a diverse marine habitat. Gastropod fossils, representing families such as Strombidae, Drilliidae, and Conidae, provided further evidence of a thriving marine environment. The paleoenvironmental reconstruction suggests clear and warm and shallow waters with nutrient-rich conditions, supporting diverse ecosystems and intricate ecological interactions. The biostratigraphic classification reveals three distinct layers at upper middle and lower horizons characterized by coral, oyster, and gastropod dominance, respectively, offering a timeline of environmental changes during the late Miocene. Preservation modes, including casts, molds, and mineral recrystallization, indicate favorable conditions for fossil retention. These findings enhance our understanding of the paleoenvironmental history of the Aruwakkalu region in Sri Lanka and provide a basis for future research in paleontology and evolutionary biology.