The rise and fall of methanotrophy following a deepwater oil-well blowout

The blowout of the Macondo oil well in the Gulf of Mexico in April 2010 injected up to 500,000 tonnes of natural gas, mainly methane, into the deep sea1. Most of the methane released was thought to have been consumed by marine microbes between July and August 20102, 3. Here, we report spatially extensive measurements of methane concentrations and oxidation rates in the nine months following the spill. We show that although gas-rich deepwater plumes were a short-lived feature, water column concentrations of methane remained above background levels throughout the rest of the year. Rates of microbial methane oxidation peaked in the deepwater plumes in May and early June, coincident with a rapid rise in the abundance of known and new methane-oxidizing microbes. At this time, rates of methane oxidation reached up to 5,900 nmol l−1 d−1—the highest rates documented in the global pelagic ocean before the blowout4. Rates of methane oxidation fell to less than 50 nmol l−1 d−1 in late June, and continued to decline throughout the remainder of the year. We suggest the precipitous drop in methane consumption in late June, despite the persistence of methane in the water column, underscores the important role that physiological and environmental factors play in constraining the activity of methane-oxidizing bacteria in the Gulf of Mexico

History, epidemiology and regional diversities of urolithiasis

Archeological findings give profound evidence that humans have suffered from kidney and bladder stones for centuries. Bladder stones were more prevalent during older ages, but kidney stones became more prevalent during the past 100 years, at least in the more developed countries. Also, treatment options and conservative measures, as well as ‘surgical’ interventions have also been known for a long time. Our current preventive measures are definitively comparable to those of our predecessors. Stone removal, first lithotomy for bladder stones, followed by transurethral methods, was definitively painful and had severe side effects. Then, as now, the incidence of urolithiasis in a given population was dependent on the geographic area, racial distribution, socio-economic status and dietary habits. Changes in the latter factors during the past decades have affected the incidence and also the site and chemical composition of calculi, with calcium oxalate stones being now the most prevalent. Major differences in frequency of other constituents, particularly uric acid and struvite, reflect eating habits and infection risk factors specific to certain populations. Extensive epidemiological observations have emphasized the importance of nutritional factors in the pathogenesis of urolithiasis, and specific dietary advice is, nowadays, often the most appropriate for prevention and treatment of urolithiasis

Carbon transport in the bottom boundary layer. Final report

The authors objective was to characterize distributions of chloropigment fluorescence in relation to physical processes in the benthic boundary layer in support of the Department of Energy (DOE) Ocean Margins Program`s (OMP) goal of quantifying carbon transport across the continental shelf. Their approach involved participation in the Ocean Margins Program (OMP) field experiment on the continental shelf off Cape Hatteras by conducting multi-sensor fluorescence measurements of photosynthetic pigments. Specific tasks included (1) pre- and post-deployment calibration of multiple fluorescence sensors in conjunction with Woods Hole personnel; (2) collection and analysis of photosynthetic pigment concentrations and total particulate carbon in water column samples to aid in interpretation of the fluorescence time-series during the field experiment; (3) collaboration in the analysis and interpretation of 1994 and 1996 time-series data in support of efforts to quantify pigment and particulate organic carbon transport on the continental shelf off Cape Hatteras. This third component included analysis of data obtained with a multi-sensor fiber-optic fluorometer in the benthic boundary layer of the inner shelf off Cape Hatteras during summer 1994

Mola Mola, NIUST\u27s Low Altitude Photo and Multibeam AUV

Mola Mola is a seafloor mapping AUV owned and operated by the National Institute for Undersea Science and Technology (NIUST). Its primary sensor is a downward-facing camera producing color-corrected seafloor imagery which, with proper navigation and post processing, can be converted to a photo mosaic. It also uses a multibeam sonar to gather bathymetry encompassing the photo coverage. Since its delivery in May of 2009 Mola Mola has been modified in the areas of its imaging and navigation systems as well as several mechanical systems. ©2010 IEEE

Advanced Technology In Motion: NIUST\u27s AUV Fleet

The National Institute for Undersea Science and Technology (NIUST) owns and operates two Autonomous Underwater Vehicles, an International Submarine Engineering built Explorer class AUV and a Woods Hole Oceanographic Institution built Seabed AUV. These two AUVs have completely different operational requirements and tasks based on their physical layout and propulsion. The torpedo-shaped explorer class AUV is used for multibeam mapping and carrying third-party or experimental instrument payloads. The Seabed AUV, propelled by three independent thrusters, is used for close-up sub-sea photographic and multi-beam site investigation which takes advantage of its slow speed and maneuverability. The high resolution digital photography can be used to construct spatial photomosaicis of the target area. Both vehicles will be introduced during this talk, highlighting their operational parameters and presenting some of the data collected with each results from previous deployments of the systems. ©2009 MTS

Enhancing NIUSTs SeaBED Class AUV, Mola Mola

Mola is a seafloor mapping AUV owned and operated by the National Institute for Undersea Science and Technology (NIUST). Since its initial sea trials in May of 2009, effort has been applied to enhancing the navigation and imaging systems for high-resolution surveys of specific targets in depths up to 2000 meters. These surveys require accurate positioning during the initial dive to the seafloor, and smooth navigation once the survey begins. To work toward this goal, an inertial navigation system with position and velocity aiding has been integrated with the vehicle software, and it is currently being field tested. The imaging system has also been modified by adding LED arrays to provide more consistent lighting and by merging navigation data with the images for georeferencing. The above system enhancements have forced changes in the vehicle\u27s layout, and operational experiences have led to improvements in the vehicle\u27s mechanical systems. © 2010 IEEE

Simultaneous Operation of Heterogeneous AUVs

This paper discusses the experiences of operating two AUVs in parallel and the modifications to equipment and protocol to make these operations possible. The two AUVs include a low-altitude, hovering, photo survey vehicle and a broader-coverage sonar mapping vehicle. At the expense of operational and technical complexities, these two vehicles and their support equipment have been operated together in order to make efficient use of available ship time. © 2013 MTS

The Effectiveness of Using MODIS Products To Map Sea Surface Oil

This project describes the effectiveness of using standard Moderate Resolution Imaging Spectroradiometer (MODIS) imagery and products, produced by NASA and distributed through the Distributed Active Archive Centers (DAACs), to monitor and map oil on the surface of the Gulf of Mexico from the oil release at the Deepwater Horizon site. With twice daily coverage of the Gulf of Mexico and the rest of the world, MODIS is well suited to monitor the effects of these types of incidents on the sea surface. MODIS imagery has been widely used by many federal, state, and local agencies, as well as the media and non-government groups to illustrate the distribution and movement of surface oil. The MODIS products evaluated for their effectiveness in mapping and monitoring oil and the sea surface include: imagery, sea surface temperature (available for nighttime and daytime temperatures), chlorophyll concentration, particulate organic/inorganic carbon, chromophoric dissolved organic matter index, diffuse attenuation coefficient, and remote sensing reflectance. These products were chosen because they are available on a daily basis. Some MODIS standard products are only available as eight-day composites which would not be as useful for monitoring a feature as dynamic as oil moving on the sea surface. MODIS standard products are produced by applying atmospheric corrections and algorithms to selected bands of MODIS data. The bands primarily used for ocean products are bands 8-16 which have a spatial resolution of 1 km. Additional products may be evaluated. The Deepwater Horizon oil rig exploded and caught fire on April 20, 2010. The drilling platform sank several days later. The well ruptured at the seafloor, 5000 feet below the sea surface, and began leaking a combination of crude oil and natural gas. As of July 15, 2010, the oil leak was capped. The Deepwater Horizon site is located approximately 58 miles southeast of the mouth of the Mississippi River in southeastern Louisiana. The effectiveness of the MODIS products was determined by comparing the MODIS data with surface water samples and digital photography taken aboard the research vessel Pelican between May 5 and May 15, 2010 within the Gulf of Mexico. During that scientific mission, the presence or lack of surface oil was reported, coordinate locations were recorded, and water and oil samples were collected. The majority of these samples were taken within 10 miles of the Deepwater Horizon site, while some were taken up to 72 miles away. During the research trip aboard the Pelican, the surface oil was not consistently present in some areas, but tended to shift due to wind and currents. Particular sites have a useful temporal aspect since they were repeatedly visited for sampling. Sun glint areas on MODIS true color imagery make surface oil especially evident. It is anticipated that the MODIS standard products will detect the oil on the sea surface that is not evident in the visible portion of the imagery spectra. ©2010 IEEE

New Developments For the NIUST AUVs

The National Institute for Undersea Science and Technology operates two AUVs, Eagle Ray and Mola Mola that are primarily tasked with performing seafloor surveys. Upcoming missions will require surveys at 1200 to 1600 meters depth, so the vehicles are being prepared with new and updated systems and software. Recently, Eagle Ray was equipped with new batteries and a subbottom profiler. A descent weight system was added to Mola Mola, along with a revised power system and new mission capabilities. © 2012 IEEE