Visualizing the Geology of Lake Trout Spawning Sites: Northern Lake Michigan

Geologists and biologists are working together to understand the links between lake floor geology (composition and shape) and the distribution of lake trout throughout their life cycle. Lake floor geology is one of the main factors determining where lake trout spawn, feed, and hide. In support of ongoing research to study Lake Michigan trout habitats, the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers mapped the morphology of principle lake trout spawning sites. Using the Army Corps of Engineer\u27s SHOALS airborne lidar (Light Detection and Ranging) system we mapped six regions in Northern Lake Michigan in order to identify ideal spawning regions composed of shallow, clean, gravel/cobble substrate, adjacent to deeper water. Lidar mapping systems, which use laser pulses to measure water depths from an airplane, are now available to map the nearshore lake morphology at meter-scale detail. Maps generated from the bathymetric data are used to define regions with smooth homogeneous substrate, regions with higher relief, and mixed regions with both smooth and rough relief. This morphologic information combined with sediment samples and direct bottom observations enable geologists to map areas with rougher relief composed of rock outcrop, boulders, and cobbles, as well as smooth regions covered with sand or mud. This information helps biologists, fishery managers, and ecologists visualize the lake floor in significant detail which promotes better fishery management, species protection, and habitat identification. These maps present the maps and discuss the geology of the six lake trout spawning sites mapped by the lidar system. Where the mapping approached land, aerial photography of the land is combined with the bathymetric data to help visualize the scale of the offshore features. Map and perspective views of Boulder Reef, Hog Island Reef, and Little Traverse Bay are shown on sheet 1, whereas map and perspective views of Trout and High Island Shoal, Gull Island Reef, and Dahlia Shoal are shown on sheet 2. Additional information, bathymetric data, imagery, and metadata are available online athttp://geopubs.wr.usgs.gov/open-file/of03-120/

Physiography and Late Quaternary-Holocene Processes of Northeastern Gulf of Mexico Outer Continental Shelf off Mississippi and Alabama

High-resolution multibeam mapping of the mid- and outer continental shelf and upper slope off Mississippi and Alabama reveals a complex bathymetry that reflects conditions during the last eustatic rise and the present high stand of sea level. The most prominent bathymetric features are pinnacles and hardgrounds that are scattered throughout the area. These features generally stand \u3c10 m above the surrounding seafloor, cover large areas, and display a variety of morphologies. Almost all the reef pinnacles and hardgrounds have zones of high acoustic backscatter on their summits and on the seafloor immediately adjacent to their southwest walls. In addition, they also have erosional moats on the seafloor to the southwest. Large fields of bedforms are scattered throughout the mapped area. The asymmetries and orientations of the bedforms suggest that they were formed by excursions of the northeast-flowing Loop Current. In contrast, the pervasive ponding of sediment on the northeast sides of bathymetric highs indicates that one of the predominant directions of sediment transport has been to the south and southwest. The shelf break is a zone of numerous landslides of various sizes and complexities. The morphology of several landslide scars indicates that some of the failures occurred recently. One large reef-capped salt dome was mapped in the area, surrounded by a large field of pockmarks. Fields of pockmarks are also scattered on the shelf. The growth and demise of the reefs are related to the fluctuating transgression of eustatic sea level during the last deglaciation. Two episodes of reef drowning are correlated with the increased rates of sea-level rise during documented melt-water pulses; the first occurred from 14.8 to 14.2 ka and the second from 11.8 to 11.2 ka. Rates of sea-level rise exceeded the maximum growth rate of hermatypic corals only during these two intervals since the last glacial maximum and thus drowned the coral communities

Physiography and Late Quaternary-Holocene Processes of Northeastern Gulf of Mexico Outer Continental Shelf off Mississippi and Alabama

High-resolution multibeam mapping of the mid- and outer continental shelf and upper slope off Mississippi and Alabama reveals a complex bathymetry that reflects conditions during the last eustatic rise and the present high stand of sea level. The most prominent bathymetric features are pinnacles and hardgrounds that are scattered throughout the area. These features generally stand \u3c10 m above the surrounding seafloor, cover large areas, and display a variety of morphologies. Almost all the reef pinnacles and hardgrounds have zones of high acoustic backscatter on their summits and on the seafloor immediately adjacent to their southwest walls. In addition, they also have erosional moats on the seafloor to the southwest. Large fields of bedforms are scattered throughout the mapped area. The asymmetries and orientations of the bedforms suggest that they were formed by excursions of the northeast-flowing Loop Current. In contrast, the pervasive ponding of sediment on the northeast sides of bathymetric highs indicates that one of the predominant directions of sediment transport has been to the south and southwest. The shelf break is a zone of numerous landslides of various sizes and complexities. The morphology of several landslide scars indicates that some of the failures occurred recently. One large reef-capped salt dome was mapped in the area, surrounded by a large field of pock-marks. Fields of pockmarks are also scattered on the shelf. The growth and demise of the reefs are related to the fluctuating transgression of eustatic sea level during the last deglaciation. Two episodes of reef drowning are correlated with the increased rates of sea-level rise during documented melt-water pulses; the first occurred from 14.8 to 14.2 ka and the second from 11.8 to 11.2 ka. Rates of sea-level rise exceeded the maximum growth rate of hermatypic corals only during these two intervals since the last glacial maximum and thus drowned the coral communities

Fluorescence characterization of clinically-important bacteria

Healthcare-associated infections (HCAI/HAI) represent a substantial threat to patient health during hospitalization and incur billions of dollars additional cost for subsequent treatment. One promising method for the detection of bacterial contamination in a clinical setting before an HAI outbreak occurs is to exploit native fluorescence of cellular molecules for a hand-held, rapid-sweep surveillance instrument. Previous studies have shown fluorescence-based detection to be sensitive and effective for food-borne and environmental microorganisms, and even to be able to distinguish between cell types, but this powerful technique has not yet been deployed on the macroscale for the primary surveillance of contamination in healthcare facilities to prevent HAI. Here we report experimental data for the specification and design of such a fluorescence-based detection instrument. We have characterized the complete fluorescence response of eleven clinically-relevant bacteria by generating excitation-emission matrices (EEMs) over broad wavelength ranges. Furthermore, a number of surfaces and items of equipment commonly present on a ward, and potentially responsible for pathogen transfer, have been analyzed for potential issues of background fluorescence masking the signal from contaminant bacteria. These include bedside handrails, nurse call button, blood pressure cuff and ward computer keyboard, as well as disinfectant cleaning products and microfiber cloth. All examined bacterial strains exhibited a distinctive double-peak fluorescence feature associated with tryptophan with no other cellular fluorophore detected. Thus, this fluorescence survey found that an emission peak of 340nm, from an excitation source at 280nm, was the cellular fluorescence signal to target for detection of bacterial contamination. The majority of materials analysed offer a spectral window through which bacterial contamination could indeed be detected. A few instances were found of potential problems of background fluorescence masking that of bacteria, but in the case of the microfiber cleaning cloth, imaging techniques could morphologically distinguish between stray strands and bacterial contamination

Research Trends and Future Perspectives in Marine Biomimicking Robotics

Mechatronic and soft robotics are taking inspiration from the animal kingdom to create new high-performance robots. Here, we focused on marine biomimetic research and used innovative bibliographic statistics tools, to highlight established and emerging knowledge domains. A total of 6980 scientific publications retrieved from the Scopus database (1950–2020), evidencing a sharp research increase in 2003–2004. Clustering analysis of countries collaborations showed two major Asian-North America and European clusters. Three significant areas appeared: (i) energy provision, whose advancement mainly relies on microbial fuel cells, (ii) biomaterials for not yet fully operational soft-robotic solutions; and finally (iii), design and control, chiefly oriented to locomotor designs. In this scenario, marine biomimicking robotics still lacks solutions for the long-lasting energy provision, which presently hinders operation autonomy. In the research environment, identifying natural processes by which living organisms obtain energy is thus urgent to sustain energy-demanding tasks while, at the same time, the natural designs must increasingly inform to optimize energy consumption

Ionization of the Venusian atmosphere from solar and galactic cosmic rays

The atmospheres of the terrestrial planets are exposed to solar and galactic cosmic rays, the most energetic of which are capable of affecting deep atmospheric layers through extensive nuclear and electromagnetic particle cascades. In the Venusian atmosphere, cosmic rays are expected to be the dominant ionization source below ∼100 km altitude. While previous studies have considered the effect of cosmic ray ionization using approximate transport methods, we have for the first time performed full 3D Monte Carlo modelling of cosmic ray interaction with the Venusian atmosphere, including the contribution of high-Z cosmic ray ions (Z=1-28). Our predictions are similar to those of previous studies at the ionization peak near 63 km altitude, but are significantly different to these both above and below this altitude. The rate of atmospheric ionization is a fundamental atmospheric property and the results of this study have wide-reaching applications in topics including atmospheric electrical processes, cloud microphysics and atmospheric chemistry

Developing technological synergies between deep-sea and space research

Recent advances in robotic design, autonomy and sensor integration create solutions for the exploration of deep-sea environments, transferable to the oceans of icy moons. Marine platforms do not yet have the mission autonomy capacity of their space counterparts (e.g., the state of the art Mars Perseverance rover mission), although different levels of autonomous navigation and mapping, as well as sampling, are an extant capability. In this setting their increasingly biomimicked designs may allow access to complex environmental scenarios, with novel, highly-integrated life-detecting, oceanographic and geochemical sensor packages. Here, we lay an outlook for the upcoming advances in deep-sea robotics through synergies with space technologies within three major research areas: biomimetic structure and propulsion (including power storage and generation), artificial intelligence and cooperative networks, and life-detecting instrument design. New morphological and material designs, with miniaturized and more diffuse sensor packages, will advance robotic sensing systems. Artificial intelligence algorithms controlling navigation and communications will allow the further development of the behavioral biomimicking by cooperating networks. Solutions will have to be tested within infrastructural networks of cabled observatories, neutrino telescopes, and off-shore industry sites with agendas and modalities that are beyond the scope of our work, but could draw inspiration on the proposed examples for the operational combination of fixed and mobile platforms

Predicted Seafloor Facies of Central Santa Monica Bay, California

Mapping surficial seafloor facies (sand, silt, muddy sand, rock, etc.) should be the first step in marine geological studies and is crucial when modeling sediment processes, pollution transport, deciphering tectonics, and defining benthic habitats. This report outlines an empirical technique that predicts the distribution of seafloor facies for a large area offshore Los Angeles, CA using high-resolution bathymetry and co-registered, calibrated backscatter from multibeam echosounders (MBES) correlated to ground-truth sediment samples. The technique uses a series of procedures that involve supervised classification and a hierarchical decision tree classification that are now available in advanced image-analysis software packages. Derivative variance images of both bathymetry and acoustic backscatter are calculated from the MBES data and then used in a hierarchical decision-tree framework to classify the MBES data into areas of rock, gravelly muddy sand, muddy sand, and mud. A quantitative accuracy assessment on the classification results is performed using ground-truth sediment samples. The predicted facies map is also ground-truthed using seafloor photographs and high-resolution sub-bottom seismic-reflection profiles. This Open-File Report contains the predicted seafloor facies map as a georeferenced TIFF image along with the multibeam bathymetry and acoustic backscatter data used in the study as well as an explanation of the empirical classification process

Multibeam Mapping of the Los Angeles, California Margin

The Los Angeles, California Margin was mapped using multibeam echosounders during three separate surveys (Figure 1). In 1996, the USGS surveyed the shelf and slope in Santa Monica Bay from Pt. Dume to south of the Palos Verdes Peninsula. The mapping was accomplished using a Kongsberg Simrad EM1000 multibeam sonar system that provided high-quality bathymetry and quantitative backscatter. In 1998, the USGS continued the mapping to the south and surveyed the outer shelf, slope, and proximal basin off Long Beach and Newport using a Kongsberg Simrad EM300 multibeam sonar system. In 1999, the Los Angeles Margin mapping was completed with the surveying of the inner Long Beach shelf from the Palos Verdes Peninsula, south to Newport. This survey used a dual Kongsberg Simrad EM3000D multibeam sonar system