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

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.

An Analysis of the Temperature Profiles of Some Antarctic Lakes

<p>The temperature profiles of certain lakes in Taylor Valley, Victoria Land, Antarctica, are shown to be consistent with the hypothesis that these lakes were formerly cold brine pools; that their levels were raised by the addition of fresh water; and that they have since been heated principally by the absorption of sunlight. The temperature profile of a lake in Wright Valley, Victoria Land, is shown to be consistent with the hypothesis that this lake was formerly warm and stable, as are those Taylor Valley lakes which were analysed; that the addition of a further large quantity of fresh water caused instability and limited convection; and that the heat source is again absorbed sunlight. The study of this lake requires an understanding of convection in the presence of a gradient of solute concentration. A survey of existing knowledge of this type of convection shows that it is inadequate for the task. Experiments which provide the necessary information are described.</p>

An Analysis of the Temperature Profiles of Some Antarctic Lakes

<p>The temperature profiles of certain lakes in Taylor Valley, Victoria Land, Antarctica, are shown to be consistent with the hypothesis that these lakes were formerly cold brine pools; that their levels were raised by the addition of fresh water; and that they have since been heated principally by the absorption of sunlight. The temperature profile of a lake in Wright Valley, Victoria Land, is shown to be consistent with the hypothesis that this lake was formerly warm and stable, as are those Taylor Valley lakes which were analysed; that the addition of a further large quantity of fresh water caused instability and limited convection; and that the heat source is again absorbed sunlight. The study of this lake requires an understanding of convection in the presence of a gradient of solute concentration. A survey of existing knowledge of this type of convection shows that it is inadequate for the task. Experiments which provide the necessary information are described.</p>

Novel Enzymes From the Red Sea Brine Pools: Current State and Potential

The Red Sea is a marine environment with unique chemical characteristics and physical topographies. Among the various habitats offered by the Red Sea, the deep-sea brine pools are the most extreme in terms of salinity, temperature and metal contents. Nonetheless, the brine pools host rich polyextremophilic bacterial and archaeal communities. These microbial communities are promising sources for various classes of enzymes adapted to harsh environments – extremozymes. Extremozymes are emerging as novel biocatalysts for biotechnological applications due to their ability to perform catalytic reactions under harsh biophysical conditions, such as those used in many industrial processes. In this review, we provide an overview of the extremozymes from different Red Sea brine pools and discuss the overall biotechnological potential of the Red Sea proteome.

First Insights into the Microbiology of Three Antarctic Briny Systems of the Northern Victoria Land

Different polar environments (lakes and glaciers), also in Antarctica, encapsulate brine pools characterized by a unique combination of extreme conditions, mainly in terms of high salinity and low temperature. Since 2014, we have been focusing our attention on the microbiology of brine pockets from three lakes in the Northern Victoria Land (NVL), lying in the Tarn Flat (TF) and Boulder Clay (BC) areas. The microbial communities have been analyzed for community structure by next generation sequencing, extracellular enzyme activities, metabolic potentials, and microbial abundances. In this study, we aim at reconsidering all available data to analyze the influence exerted by environmental parameters on the community composition and activities. Additionally, the prediction of metabolic functions was attempted by the phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2) tool, highlighting that prokaryotic communities were presumably involved in methane metabolism, aromatic compound biodegradation, and organic compound (proteins, polysaccharides, and phosphates) decomposition. The analyzed cryoenvironments were different in terms of prokaryotic diversity, abundance, and retrieved metabolic pathways. By the analysis of DNA sequences, common operational taxonomic units ranged from 2.2% to 22.0%. The bacterial community was dominated by Bacteroidetes. In both BC and TF brines, sequences of the most thermally tolerant and methanogenic Archaea were detected, some of them related to hyperthermophiles.

Characterizing Dispersion Effectiveness at Varying Salinities

ABSTRACT Chemical dispersant formulations typically provide maximum oil dispersion in waters between 30–40 ppt (parts per thousand) salt content, which encompasses typical ocean salinity (~34 ppt). As a result, most laboratory studies of oil dispersion effectiveness (DE) are conducted at low to average ocean salinity. Ocean salinity can vary locally from below 20 ppt during ice and snow melt, to extremely high (over 100 ppt) during freeze up periods or within natural brine pools in deeper waters. In this study, the influence of salinity on DE was evaluated using the baffled flask test (BFT) at a dispersant-to-oil ratio (DOR) of 1:25. Benchtop experiments were conducted with Alaskan North Slope (ANS) crude oil in the presence or absence of chemical dispersant at 5 and 25°C and varying salinities (0.2 to 125 ppt). In addition to DE as determined by BFT, oil droplet size distribution (DSD) and fluorescence intensity was measured via a LISST-100X particle size analyzer (Sequoia Scientific, Inc., Bellevue, WA) and ECO fluorometer (Sea Bird - WET Labs, Inc.; Philomath, OR), respectively. Results indicate that in the presence of dispersant, maximum DE occurred at 25ppt, and decreases above and below this salinity. Concentration of small droplets (&lt;10 μm) was twice as high at 35ppt than at the other salinities in the presence of dispersant at 25°C. Treatments without dispersant did not vary significantly as a function of salinity. Flume tank experiments over a range of salinities support the lab scale results of DSD. These results provide a more comprehensive picture pertaining to the influence of salinity on dispersant usage at high salinities.

The Red Sea Metalliferous Sediments

&lt;p&gt;The demand for metals and raw materials continues to increase as onshore deposits become more depleted. Our oceans contain large unexplored areas that may contain new resources in the form of Mn-nodules, Co-rich crusts, and massive sulfides. A complete characterization and assessment of these deposits are fundamental for the evaluation of resource extraction, separation, and disposal processes.&lt;/p&gt;&lt;p&gt;The Red Sea holds unique examples of sediment accumulations formed under distinctive environmental conditions. The Atlantis II deep is located in the central part of the Red Sea at 2 km depth and on top of the spreading axis. This deep accumulates sediments that result predominantly from the discharge of hydrothermal fluids into hot and stratified brine pools. The changes in environmental conditions and the hydro-chemical conditions in the brine pool control sediment formation. The accumulations are enriched with metals, such as Ag, Au, Cu, Co, and Zn. The sediments in this deep hold a record of the formation history and their brine pools tell a story about on-going processes.&lt;/p&gt;&lt;p&gt;On-going research at the Energy Geo-Engineering Laboratory EGEL, KAUST includes (1) Geotechnical index properties (liquid limit, grain size distribution, and specific surface) and consolidation tests to infer engineering properties, (2) Sediment classification based on the Revised Soil Classification System, (3) Geochemistry and mineralogy using XRD, ICP-OES and (4) Microstructure and texture with SEM imaging. An advanced sediment characterization of these fine-grained metalliferous deposits gives a comprehensive understanding of the soil behavior.&lt;/p&gt;