Early development of a deep sea volcano offshore Mayotte revealed by seafloor mapping : first results from the MAYOBS cruises

2020 ◽  
Author(s):  
Christine Deplus ◽  
Nathalie Feuillet ◽  
Isabelle Thinon ◽  
Stephan Jorry ◽  
Yves Fouquet ◽  
...  
Keyword(s):  
Early Development ◽  
Morphological Evolution ◽  
Seafloor Mapping ◽  
Sea Bottom ◽  
Gravity And Magnetic ◽  
First Results ◽  
High Backscatter ◽  
High Resolution Bathymetry ◽  
Underwater Camera ◽  
Steep Slopes

<p>The early development and growth of seamounts are poorly known as the birth of a volcano on the sea bottom has been rarely observed. The on-going Mayotte seismo-volcanic crisis is associated with the formation of a new seafloor volcano at a water depth of 3300 m and provides the opportunity to study its early development.</p><p>Four oceanographic cruises, MAYOBS 1 to 4, were carried out between May and July 2019 aboard the French R/V Marion Dufresne. High resolution bathymetry and backscatter data as well as sub-bottom profiler, gravity and magnetic profiles were collected during each cruise. A dense network of profiles has been achieved over the new volcano at different epochs, allowing to assess its detailed morphology and the evolution through time. During MAYOBS4, a deep-towed underwater camera provided sea bottom videos and photos on the volcano.</p><p>First results indicate that the new volcano is still growing at the end of July 2019. Repetitive surveys in May, June and July 2019 allow to document the morphological evolution of the volcano, to estimate the volume of material emplaced between each epoch and to discuss the emitted lava rate.</p><p>The new volcano has a starfish shape and is now 820 m high. Steep slopes are observed close to the summit and several radial ridges developed from its central part, displaying hummocky morphology similar to the ones observed along mid oceanic axial volcanic ridges. At the bottom, flat areas with high backscatter could indicate channelized lava flows emplaced at higher effusion rates. The morphological analysis combined with video imagery brings constraints to the eruptive processes yielding to the formation of a nascent volcano.</p><p> </p>

Sea bottom characteristics and geochemistry of oil and gas seeps in the Gulf of Mexico

2021 ◽  
pp. 1-60
Author(s):  
John Decker ◽  
Philip Teas ◽  
Daniel Orange ◽  
Bernie B. Bernard
Keyword(s):  
Gulf Of Mexico ◽  
Gas Hydrates ◽  
Oil And Gas ◽  
Geochemical Analysis ◽  
Mud Volcanoes ◽  
Sea Bottom ◽  
High Backscatter ◽  
Oil Extract ◽  
Brine Pools ◽  
Gas Seeps

From 2015 to 2018, TGS conducted a comprehensive multiclient oil and gas seep hunting survey in the Gulf of Mexico. The basis for identifying seeps on the sea bottom was a high-resolution Multi-Beam Echo Sounder survey, mapping approximately 880,000 km2 of the sea bottom deeper than 750 m water depth, at a bathymetric resolution of 15 m and a backscatter resolution of 5 m. We have identified more than 5000 potential oil and/or gas seeps, and of those, we cored approximately 1500 for hydrocarbon geochemical analysis. The sea bottom features best related to hydrocarbon seepage in the GoM are high backscatter circular features with or without bathymetric expression, high backscatter features with “flow” appearance, mud volcanoes, pock marks, brine pools, “popcorn” texture, faults, and anticlinal crests. We also tracked gas plumes in the water column back to the sea bottom to provide an additional criterion for hydrocarbon seepage. Cores from sea bottom targets recovered liquid oil, tar, and gas hydrates. Oil extract and gas analyses of samples from most target types produced values substantially higher than background in oil and gas.

scholarly journals Early development of verb-constructions in an English-speaking child

2000 ◽  
Vol 18 ◽  
pp. 39-52
Author(s):  
Insa Gülzow
Keyword(s):  
Early Development ◽  
Morphological Development ◽  
Verb Morphology ◽  
Verb Constructions ◽  
First Results ◽  
English Speaking ◽  
L1 English

In this paper the first results concerning the development of early verb morphology in an L1-English speaking child are presented. Adopting the framework of morphological development of Dressler (Dressler, this volume) the data of a girl from the CHILDES database, Nina of the Suppes corpus, is analysed with regard to the emergence of early verbal categories (e.g. number and person) and their appearance in a first mini-paradigm. In the sessions analysed so far the child Nina has reached an age of 2;2 when the first mini-paradigm emerges.  

The temporality of transformation: dating the early development of the southern British Neolithic

2007 ◽  
Author(s):  
Alasdair Whittle
Keyword(s):  
Early Development ◽  
Neolithic Transition ◽  
First Results

This chapter has three aims: first, to draw attention to now-routine methods of refining radiocarbon chronologies; second, to sketch some of the first results from the application of such methods to early (but not yet really the earliest) parts of the southern British Neolithic sequence; and third, to discuss on a provisional basis the implications of a more refined sequence for our understanding of the Mesolithic–Neolithic transition and the very early development of the southern British Neolithic. In so doing, the distinctions between chronology, history, and temporality become harder to sustain.

An Epibenthic Sledge for Operations on Marine Soft Bottom and Bedrock

2005 ◽  
Vol 39 (2) ◽  
pp. 10-21 ◽  
Author(s):  
Nils Brenke
Keyword(s):  
Deep Water ◽  
Mechanical Stability ◽  
Benthic Macrofauna ◽  
Soft Bottom ◽  
Epibenthic Sledge ◽  
Marine Habitats ◽  
Antarctic Waters ◽  
First Results ◽  
Steep Slopes ◽  
High Mechanical Stability

A multi-purpose epibenthic sledge, designed for sampling of small benthic macrofauna in marine habitats and at any navigable depth, is presented. The new epibenthic sledge operates reliably on soft sediments in shallow and in open oceanic deep water, as well as on steep slopes, between rocks and glacier moraines as frequently found in Antarctic waters, and on primary hard substrate. The construction is of high mechanical stability with fully protected nets. In case of damage, parts of the sledge can be replaced or repaired easily on board. A description of the gear with a detailed construction plan, as well as parameters for handling in diverse marine habitats, is given. Calculation of the towing distance and first results with possible sources of errors are discussed.

Early development of Betta splendens under stereomicroscopy and scanning electron microscopy

Zygote ◽  
2013 ◽  
Vol 23 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Fernanda Nogueira Valentin ◽  
Nivaldo Ferreira do Nascimento ◽  
Regiane Cristina da Silva ◽  
João Batista Kochenborger Fernandes ◽  
Luiz Gustavo Giannecchini ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Early Development ◽  
Developmental Stages ◽  
Relevant Information ◽  
Betta Splendens ◽  
Egg Cell ◽  
Larval Body ◽  
First Results ◽  
Scanning Electron

SummaryBetta splendens is a very important ornamental species. The current paper describes the embryonic and larval development of B. splendens under stereomicroscopy and scanning electron microscopy. Eggs and larvae from natural spawning were collected at different developmental stages at previously established intervals and analysed. The eggs of B. splendens are yellowish, clear, spherical, demersal, translucent and telolecithal with a large amount of yolk. Between 0–2 h post-initial collection (hpIC), the eggs were at the egg cell, first cleavage and morula stages. The blastula stage was identified at 2–3 hpIC and the early gastrula phase was observed at 3–4 hpIC with 20% epiboly, which was finalized after 13–18 hpIC. When the pre-larvae were ready to hatch, the appearance of somites and the free tail were observed, at 23–25 hpIC. At 29 hpIC, the majority of larvae had already hatched at an average temperature of 28.4 ± 0.2°C. The newly hatched larvae measured 2.47 ± 0.044 mm total length. The mouth opened at 23 h post-hatching (hPH) and the yolk sac was totally absorbed at 73 hPH. After 156 hPH, the heart was pumping blood throughout the entire larval body. The caudal fin, operculum and eyes were well developed at 264 hPH. When metamorphosis was complete at 768 hPH, the larvae became juveniles. The current study presents the first results about early development of B. splendens and provides relevant information for its reproduction, rearing and biology.

VM-ADCP backscatter data management using QGIS

2020 ◽  
Author(s):  
Paola Picco ◽  
Roberto Nardini ◽  
Sara Pensieri ◽  
Roberto Bozzano ◽  
Luca Repetti ◽  
...  
Keyword(s):  
Acoustic Doppler Current Profiler ◽  
Relevant Information ◽  
Ocean Currents ◽  
Acoustic Backscatter ◽  
Ligurian Sea ◽  
Current Profiler ◽  
High Backscatter ◽  
Set Up ◽  
High Resolution Bathymetry ◽  
Sampling Set

<p>VM-ADCP (Vessel Mounted Acoustic Doppler Current Profiler) are regularly operating on board of several research vessels with the aim of providing 3-D ocean currents fields. Along with ocean currents, these instruments also measure acoustic backscatter profile on a known frequency, that can be of great advantages for other environmental investigations such as the zooplankton migrations. The presence of zooplankton can be detected by a variation of acoustic backscatter changing  with the depth at a periodic (diurnal or semidiurnal) variability, related to the vertical  migration of these organisms. GIS has proven to be a powerful tool to manage the huge amount of VM-ADCP backscatter data obtained during the oceanographic campaigns. Moreover, this allows to extract relevant information on zooplankton distribution and abundance, even when the monitoring strategy of the experiment does not completely meet the temporal and spatial resolution required for these studies. The application here described has been developed on QGIS and tested on the Ligurian Sea (Mediterranean Sea). In order to obtain the comparability of data from instruments operating at different frequencies and sampling set-up, echo intensity data are converted into volume backscatter strength and corrected for the slant-range. Using high-resolution bathymetry rasters acquired and processed by the Italian Hydrographic Institute, allows to discard the anomalous high backscatter values due to presence of the bottom. Another advantage of the GIS is the possibility to easily identify night-collected data from the daily ones and their spatial distribution, as well as those from the surface and the deeper layer. All the possible combinations can be then visualised and analysed.</p>

A Correlated Light- and Electron-Microscope Investigation of the Structural Evolution of the Nucleolus during the Cell Cycle in Plant Meristematic Cells (Allium Porrum)

1974 ◽  
Vol 16 (1) ◽  
pp. 63-93
Author(s):  
J. G. LAFONTAINE ◽  
A. LORD
Keyword(s):  
Phase Contrast ◽  
Morphological Evolution ◽  
Structural Evolution ◽  
Particulate Material ◽  
Allium Porrum ◽  
Late Prophase ◽  
Fibrillar Material ◽  
First Results ◽  
Late Telophase ◽  
Adjacent Segments

The interphase nucleolus consists of particulate zones and of a number of skein-like regions each of which contains a complex filamentous structure or nucleolonema. DNA is known to be present within the lacunar portions of these nucleolar regions. In the course of prophase the nucleolonemata become less tortuous and take the form of elongate structures extending across the nucleolar mass. Their continuity with the nucleolar organizing chromosomes can then be much more easily established than during interphase. When the peripheral granular portion of the late prophase nucleolus begins to disperse, the nucleolonemal lacunae appear smaller and less conspicuous. Examination of serial sections discloses that these convoluted filaments progressively contract during disorganization of the nucleolus but always remain less compact than the remaining portions of the nucleolar chromosomes. At very late prophase these chromosome loops have become quite small and have evolved into rather dense, homogeneous structures made up mostly of fibrillar material. By the time the nuclear envelope breaks down, these structures appear less compact under phase-contrast optics and, judging from their progressive contraction and their change in ultrastructural characteristics, it is evident that they have undergone extensive reorganization during the nucleolar dissolution process. This striking morphological evolution of the nucleolonemata is best interpreted by assuming that they lose a great deal of their constituent material during the later part of prophase and that the remaining portion, part of which is organizer DNA, retracts back to the chromosome axis and gives rise to nucleolar secondary constrictions. From metaphase to early telophase these constrictions are observed to consist of fine fibrillar material which stains much less intensely with heavy metals than other chromosome segments. When first detected as structured bodies, the late telophase nucleoli are roundish in shape and, under phase-contrast optics, their density closely matches that of the late prophase contracted nucleolonemata. At higher magnification incipient nucleoli are found to consist of a tight glomerulus predominantly fibrillar in texture. During the early G1 period, growth of the nucleolus first results from expansion of the nucleolonemal skein and concurrent formation of numerous lacunar areas. Electron microscopy reveals that these lighter nucleolar zones contain diffuse fibrillar material similar to that observed in the lacunae of mature interphase nucleoli. Favourable preparations also show that this lacunar, fibrillar material is continuous with immediately adjacent segments of the nucleolar chromosomes. Concomitant with this expansion of the central skein region and enlargement of its lacunae, the growing nucleolus also gradually acquires an irregular layer of particulate material at its periphery. Since the formation of chromatin-containing lacunar regions and the appearance of peripheral RNP granules are found to coincide with a resumption in the RNA-synthesizing activity of the early interphase nucleous (authors' unpublished observations), growth of this organelle appears to be partly dependent on derepression of its nucleolar loops. Mid-G1 nucleoli exhibit all the morphological characterized of mature interphase organelles.

Individual differences, social attention, and the history of the social motivation hypotheses of autism

2019 ◽  
Vol 42 ◽  
Author(s):  
Peter C. Mundy
Keyword(s):  
Individual Differences ◽  
Early Development ◽  
Emotional Development ◽  
Social Motivation ◽  
Social Attention ◽  
Social Emotional Development ◽  
Social Emotional ◽  
Precise Understanding ◽  
The Social ◽  
History Of

Abstract The stereotype of people with autism as unresponsive or uninterested in other people was prominent in the 1980s. However, this view of autism has steadily given way to recognition of important individual differences in the social-emotional development of affected people and a more precise understanding of the possible role social motivation has in their early development.

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