Investigations Into the Application of Single-Beam Acoustic Backscatter for Describing Shallow Water Marine Habitats

Chapter 1 Producing thematic coral reef benthic habitat maps from single-beam acoustic backscatter has been hindered by uncertainties in interpreting the acoustic energy parameters E1 (~roughness) and E2 (~hardness), typically limiting such maps to sediment classification schemes. In this study acoustic interpretation was guided by high-resolution LIDAR (Light Detection And Ranging) bathymetry. Each acoustic record, acquired from a BioSonics DT-X echosounder and multiplexed 38 and 418 kHz transducers, was paired with a spatially-coincident value of a LIDAR-derived proxy for topographic complexity (Reef-Volume) and its membership to one of eight LIDAR-delineated benthic habitat classes. The discriminatory capabilities of the 38 and 418 kHz signals were generally similar. Individually, the E1 and E2 parameters of both frequencies differentiated between levels of LIDAR Reef-Volume and most benthic habitat classes, but could not unambiguously delineate benthic habitats. Plotted in E1:E2 Cartesian space, both frequencies formed two main groupings: uncolonized sand habitats and colonized reefal habitats. E1 and E2 were significantly correlated at both frequencies; positively over the sand habitats and negatively over the reefal habitats, where the scattering influence of epibenthic biota strengthened the E1:E2 interdependence. However, sufficient independence existed between E1 and E2 to clearly delineate habitats using the multi-echo E1/E2 Bottom Ratio method. The point-by-point calibration provided by the LIDAR data was essential for resolving the uncertainties surrounding the factors informing the acoustic parameters in a large, survey-scale dataset. The findings of this study indicate that properly interpreted single-beam acoustic data can be used to thematically categorize coral reef benthic habitats. Chapter 2 A large-scale acoustic survey was conducted in Apr-May 2008, with the objective of quantifying the abundance and distribution of seasonal drift macroalgae (DMA) in the Indian River Lagoon. Indian River was surveyed from the Sebastian Inlet to its northernmost extent in the Titusville area. Banana River was surveyed from its convergence with the Indian River northward to the Federal Manatee Zone near Cape Canaveral. The survey vessel was navigated along pre-planned lines running east-west and spaced 200 m apart. The river edges were surveyed to a minimum depth of approximately 1.3 m. Hydroacoustic data were collected with a BioSonics DT-X echosounder and two multi-plexed digital transducers operating at 38 and 418 kHz. The 38 and 418 kHz hydroacoustic data were processed with BioSonics Visual Bottom Typer (VBT) seabed classification software to obtain values of E1’ (time integral of the squared amplitude of the 1st part of the 1st echo waveform), E1 (2nd part of 1st echo), E2 (complete 2nd echo), and FD (fractal dimension characterizing the shape of the 1st echo). Following quality analysis, a training dataset was compiled from 131 hydroacoustic + video samples collected across the extent of the study area. The 38 and 418 kHz E1’, E1, E2, and FD datasets were merged and submitted to a series of three discriminant analyses (DA) to refine the training samples into three pure end-member categories; bare substrate, short SAV (typically Caluerpa prolifera, ~10cm or less), and DMA. The Fisher’s linear discriminant functions from the third and final descriptive DA were used to classify each of the 480,000+ hydroacoustic survey records as either bare, short SAV, or DMA. The classified survey records were then used to calculate the biomass of DMA as the product of average DMA cover for a block of ten records times the wet weight of DMA. The DMA biomass was found to be 69,859 metric tons (wet weight) within the 293.1 km2 study area. The acoustically-predicted mean percent cover of DMA was (i) significantly greater within the navigation channels (18.3%) than outside (12.2%), and (ii) significantly greater in the Indian River (12.9%) than in the Banana River (9.3%). The overall predictive accuracy of total SAV (i.e. short SAV plus DMA) was 78.9% (n=246) at three levels of cover (0-33, 33-66, and 66-100%). The Tau coefficient, a measure of the improvement of the classification scheme over random assignment, was 0.683 ± 0.076 (95% CI), i.e. the rate of misclassifications was 68.3% less than would be expected from random assignment of hydroacoustic records to total SAV cover. The incorporation of multi-plexed digital transducers in conjunction with new post-processing techniques realized the goal of establishing an accurate, efficient, and temporally consistent method for acoustically mapping DMA biomass. Chapter 3 This chapter presents the results of a large-scale hydroacoustic survey conducted in April-May 2008. The objective of this study was to map the distribution and vertical extent of muck in the Indian River Lagoon, utilizing the data collected during a seasonal drift macroalgae survey. Indian River was surveyed from the Sebastian Inlet to its northernmost extent in the Titusville area. Banana River was surveyed from its convergence with the Indian River northward to the Federal Manatee Zone near Cape Canaveral. The survey vessel was navigated along pre-planned lines running east-west and spaced 200 m apart, except for when muck was indicated by the oscilloscope display, at which point a meandering path was adopted to demarcate the horizontal extent of muck. Hydroacoustic data were collected with a BioSonics DT-X echosounder and two multi-plexed digital transducers operating at 38 and 420 kHz. The vertical extent of muck was derived from the 38 kHz hydroacoustic signal, which was processed with Visual Analyzer, a fish-finding software package produced by BioSonics Inc. The software was adapted to integrate echo energy below the water-sediment interface, and a set of post-processing algorithms were developed to translate the sub-bottom echo energy profile into continuous scale estimates of muck thickness. In this manner 500,000+ 38 kHz pings were translated into 88,927 geo-located estimates of muck layer thickness, down to a minimum bottom depth of 1 m. Ground-truthing was conducted in July 2008 at twenty sites within the Indian River. The predictions of muck layer thickness were found to be accurate over the ground-truthed range of 0-3m (r2 = 0.882, SE=0.52m). The vertical distribution of acoustically-predicted muck demonstrated the tendency for muck to accumulate in deeper areas of the lagoon. For the case of Indian River (excluding navigation channels), muck was not detected in depths shallower than 1.4m and rare in the range of 1.4-2.2 m (only 3.6% of records had a predicted muck thickness greater than 0.5 m). The frequency of muck plateaued between 2.2-3.4 m (9.6%) before making a sharp rise to 82% in the range of 4-5 m. As expected, the mean muck layer thickness was significantly greater within the navigation channels (0.56 m) than outside of them (0.08 m). A significant latitudinal trend of muck thickness was detected within the Indian River navigation channels. The mean muck thickness decreased from 1.38 m at its northernmost origins to 0.83 m in the Titusville area before plateauing at approximately 0.4 m for the remainder of segments. Outside of the main ICW channels, 23 individual muck deposits were identified; 22 in the Indian River and 1 in the Banana River. Factors in descending order of co-occurrence were proximity to causeways or jetties, riverbed depressions, and proximity to shore and drainage channels. In conclusion, this study establishes that a single-beam acoustic survey is a cost-effective and accurate alternative for mapping the distribution and vertical extent of muck deposits in the shallow-water environment of the Indian River Lagoon. Moreover, the temporal consistency afforded by a digital transducer allows for direct and meaningful comparisons between successive surveys. Chapter 4 A thematic map of benthic habitat was produced for a coral reef in the Republic of Palau, utilizing hydroacoustic data acquired with a BioSonics DT-X echosounder and a single-beam 418 kHz digital transducer. This paper describes and assesses a supervised classification scheme that used a series of three discriminant analyses (DA) to refine training samples into end-member structural and biological elements, utilizing E1′ (leading edge of 1st echo), E1 (trailing edge of 1st echo), E2 (complete 2nd echo), fractal dimension (1st echo shape), and depth as predictor variables. Hydroacoustic training samples were assigned to one of six predefined groups based on the plurality of benthic elements (sand, sparse SAV, rubble, pavement, rugose hardbottom, branching coral), visually estimated from spatially co-located ground-truthing videos. Records that classified incorrectly or failed to exceed a minimum probability of group membership were removed from the training dataset until only ‘pure’ end-member records remained. This refinement of ‘mixed’ training samples circumvented the dilemma typically imposed by the benthic heterogeneity of coral reefs, i.e. to either train the acoustic ground discrimination system (AGDS) on homogeneous benthos and leave the heterogeneous benthos un-classified, or attempt to capture the many ‘mixed’ classes and overwhelm the discriminatory capability of the AGDS. This was made possible by a conjunction of narrow beamwidth (6.4o) and shallow depth (1.2 to 17.5 m), which produced a sonar footprint small enough to resolve most of the microscale features used to define benthic groups. Survey data classified from the 3rd-Pass training DA were found to (i) conform to visually-apparent contours of satellite imagery, (ii) agree with the structural and biological delineations of a benthic habitat map created from visual interpretation of 2004 IKONOS imagery, and (iii) yield values of benthic cover that agreed closely with independent, contemporaneous video transects. The methodology was proven on a coral reef environment for which high quality satellite imagery existed, as an example of the potential for single-beam systems to thematically map coral reefs in deep or turbid settings where optical methods are unsatisfactory. Chapter 5 Beginning In the winter of 2003-2004, several episodes of red drift macroalgae blooms resulted in massive amounts of macroalgae washing ashore the beaches of Sanibel Island, Bonita Springs, and Ft Meyer Florida. A study conducted after the first event supported a link to increasing land-based nutrient enrichment. A large-scale program was initiated in May 2008, with the primary goal of further defining the possible roles and sources of nutrient enrichment with respect to nuisance macroalgae blooms. This study reports the results of the hydroacoustic mapping component of this program. The goal of this study was to identify areas of substrate suitable for supporting a macroalgae bloom. Areas within San Carlos Bay and offshore Sanibel Island, FL were hydroacoustically surveyed from nearshore to about 11 km offshore during the periods of October 6-10, 2008 and May 10-22, 2009. The hydroacoustic data was acquired with a BioSonics DT-X echosounder and a multiplexed single-beam digital transducers operating at 38 and 418 kHz. Eleven acoustic parameters derived from the 38 and 418 kHz signals were utilized to classify the survey data into 5 ascending categories of visually-apparent seabed roughness. Classes 1 and 2 were both primarily constituted of unconsolidated silt and sand-sized sediments, unsuitable for a bloom. Class 3 is a marginal substrate for a bloom, consisting of packed sand and large intact shell debris. Classes 4 and 5 offer the best attachment sites for a bloom, consisting of consolidated shell hash, live hardbottom, and submerged aquatic vegetation. The majority (~ 80%) of acoustic classifications were of soft bottom sediments (classes 1-2), but there were two significant expanses of rough seabed suitable for macroalgae attachment. These two areas covered a total of 19 km2, within which ~ 56% of the hydroacoustic records classified as “rough” (classes 3-5). The first was a large area of seagrass beds and live hardbottom in the mouth of San Carlos Bay, where large amounts of macroalgae were variably present during the April-May 2009 surveys. The second was offshore Lighthouse Point, near the mouth of San Carlos Bay, situated near a large sand spit that extended from the beach to approximately 6 km offshore. Along the west side of the sand spit there were substantial areas of moderate to high bottom roughness, mostly in the form of consolidated shell hash. The average depths of these two acoustically-rough areas were only 5.0 and 4.0 m, so sufficient irradiance to initiate a bloom could be assumed. These textured and shallow areas on or near the mouth of San Carlos Bay are presumably potential sources for macroalgae attachment and growth, which could easily be transported onto the beaches under some storm conditions given the close proximity to the shoreline. In contrast, the areas in open Gulf of Mexico waters were classified predominantly as soft sediments with low bottom roughness. The site offshore Redfish Pass had a moderate (~22%) proportion of “rough” classifications out to 5km offshore, but from 5-10km offshore the bottom classified as \u3e95% soft sediments. The other two Gulf of Mexico sites classified as \u3e95% soft sediments from nearshore to 11 km offshore. Independent, concurrent video transects indicated there were small areas with large amounts of shell and live hard bottom that occurred sporadically greater than 10km offshore, but all things considered the open Gulf waters around Sanibel Island may not be a major source of drift macroalgae. Chapter 6 This study presents the results of methods developed for acoustic remote sensing of Acropora cervicornis, a threatened species of scleractinian sporadically occurring on the nearshore hardbottom of Southeast Florida. The objective was to develop techniques for mapping isolated Acropora patches on a scale larger than what is feasible using on-the-ground methods. A time-series of A. cervicornis cover could inform resource managers about the fate of such patches, e.g. do they appear and vanish, creep by extension from a central point, or leap by colony fragmentation. The main challenge to acoustically mapping A. cervicornis was distinguishing it from gorgonians occupying the same habitat. Hydroacoustic surveys were conducted in October 2009 at two nearshore sites in Broward County, FL utilizing a BioSonics DT-X echosounder and multiplexed single-beam digital transducers operating at frequencies of 38 and 418 kHz. NCRI scientists have monitored the spatial extent and percent cover of A. cervicornis within these sites, providing an ideal background against which to calibrate the hydroacoustic predictions. Two approaches were evaluated. The first approach utilized BioSonics EcoSAV post-processing software, designed to predict areal cover and canopy height of submerged aquatic vegetation using a series of heuristic pattern-recognition algorithms. Anchored over A. cervicornis, the 38 and 418 kHz signals performed similarly well. Anchored over gorgonians, the 38 kHz signal detected the canopy roughly half as frequently as the 418 kHz signal. Undifferentiated 418 kHz EcoSAV cover was allocated to either A. cervicornis or gorgonians exploiting this frequency-dependent detection. The second approach utilized the acoustic energy (E0, E1′, E1, and E2) and shape (fractal dimension) parameters obtained from BioSonics Visual Bottom Typer software. A dual-frequency training dataset was used to classify records as sand, bare pavement, gorgonians, or A. cervicornis. Both approaches yielded promising results, based on a number of metrics, unambiguously demonstrating that single-beam AGDS are capable of reliably detecting A. cervicornis and gorgonians under controlled conditions

Demography and Population Dynamics of Massive Coral Communities in Adjacent High Latitude Regions (United Arab Emirates)

Individual massive coral colonies, primarily faviids and poritids, from three distinct assemblages within the southeastern Arabian Gulf and northwestern Gulf of Oman (United Arab Emirates) were studied from 2006–2009. Annual photographic censuses of approximately 2000 colonies were used to describe the demographics (size class frequencies, abundance, area cover) and population dynamics under “normal” environmental conditions. Size class transitions included growth, which occurred in 10–20% of the colonies, followed in decending order by partial mortality (3–16%), colony fission (\u3c5%) and ramet fusion (\u3c3%). Recruitment and whole colony mortality rates were low (\u3c0.7 colonies/m2) with minimal interannual variation. Transition matrices indicated that the Arabian Gulf assemblages have declining growth rates (λ\u3c1) whereas the massive coral population is stable (λ = 1) in the Gulf of Oman. Projection models indicated that (i) the Arabian Gulf population and area cover declines would be exacerbated under 10-year and 16-year disturbance scenarios as the vital rates do not allow for recovery to pre-disturbance levels during these timeframes, and (ii) the Gulf of Oman assemblage could return to its pre-disturbance area cover but its overall population size would not fully recover under the same scenarios

Accuracy Assessment and Monitoring for NOAA Florida Keys Mapping AA ROI-1 (Hawk Channel Near American Shoal)

This report describes the methodologies, analyses, and results for an independent accuracy assessment of a thematic benthic habitat map produced by NOAA for the Florida Keys. It is an analysis of four regional accuracy assessments. Over the course of the Florida Keys mapping project, NOAA amended part of the classification scheme. The original scheme for mapping benthic cover was a tiered approach where certain benthic cover categories were given priority over others (e.g. coral was most important). Recently, this was modified to a dominant benthic cover scheme where the habitat is characterized by the single most dominant cover type and all habitats are characterized for percent cover of coral. The data and data analyses from Walker and Foster (2009 and 2010) were used to evaluate the accuracy of the reclassified map for Regions Of Interest (ROI) 1 and 2. New data were collected for ROIs 3 and 4 as part of this report. All four regions were combined and analyzed to determine total map accuracy. Data were collected in January 2009 at ROI 1 (eastern Lower Keys), in June 2009 at ROI 2 (western Lower Keys), in September 2012 and February, March, and May 2013 at ROI 3 (back country), and in May 2013 at ROI 4 (Key Largo) (Figure 1). A total of 2029 sampling stations were visited, of which 1969 were used in the accuracy assessment. The sites were selected using a stratified random sampling protocol that equally distributed sampling points amongst the detailed structure categories. Most sites were sampled by deploying a weighted drop camera with the vessel drifting in idle and recording 30-120 seconds of dGPS-referenced video. The shallowest sites were sampled by snorkel, waverunner, or kayak, using a hand-held dGPS for navigation and a housed camera to record video. Each sampling station was given a Detailed Structure, Biological, and Coral Cover assignment in the field. These field classifications were reevaluated post-survey during a systematic review of video and photographic data, designed to ensure consistency within classifications. The efficacy of the benthic habitat map was assessed by a number of classification metrics derived from error matrices of the Major and Detailed levels of Geomorphological Structure and Biological Cover. The overall, producer’s, and user’s accuracies were computed directly from the error matrices. The analyses of the combined ROIs 1 – 4 gave an overall accuracy of the benthic habitat map of 90.4% and 84.6% at the Major and Detailed levels of Structure respectively, and 85.1% and 76.5% at the Major and Detailed levels of cover. The known map proportions, i.e. relative areas of mapped classes, were used to remove the bias introduced to the producer’s and user’s accuracies by differential sampling intensity (points per unit area). The overall accuracy at the Major and Detailed levels of Structure changed to 92.3% and 85.9%. The overall accuracy at the Major and Detailed levels of cover changed to 84.3% and 79%. The overall accuracies were also adjusted to the number of map categories using the Tau coefficient. Tau is a measure of the improvement of the classification scheme over a random assignment of polygons to categories, bounded between -1 (0% overall accuracy for 2 map categories) and 1 (100% accuracy for any number of categories). The Tau coefficients were 0.807 ± 0.026 and 0.829 ± 0.018 at the Major and Detailed levels of Structure, and 0.814 ± 0.020 and 0.745 ± 0.020 at the Major and Detailed levels of cover. Percent coral cover was classified for every polygon, thus coral cover was evaluated separately. Total accuracy for Coral in all habitats for all ROIs was 89.6% and 93.4% after adjusting for map marginal proportions. This calculation, however, was not realistic because it evaluated coral cover in non-coral habitat which inflated the number of correct sites. To account for this, coral cover was also evaluated at only those sites found to be Coral Reef and Hardbottom habitats. Total map accuracy for mapping coral cover on Coral Reef and Hardbottom habitats was 79.8%, and 82.7% after adjusting for habitat proportions. The accuracy varied greatly between the two coral categories present. User’s and Producer’s accuracies for Coral 0% - \u3c10% were near or equal to 90%. Conversely, Coral 10% - \u3c50% user’s and producer’s accuracies were 54.3% and 66.5% respectively. Adjusted producer’s accuracy was reduced to 55.2%. The adjustment for map proportions was very relevant here due to the large disparity of area between the two classes. The map contained 658.5 km² of Coral 0% - \u3c10% and 39.8 km² of Coral 10% -\u3c50%. Further 583 of AA points on Coral Reef and Hardbottom habitat were in Coral 0% - \u3c10% and 219 were in Coral 10% - \u3c50%. Interestingly, there were no mapped polygons of Coral 50% - \u3c90% and 90% - 100%. There was confusion between coral classes where 88 locations mapped as Coral 10% - \u3c50% were actually Coral 0% - \u3c10% and 60 locations mapped as Coral 0% - \u3c10% were found to be Coral 10% - \u3c50%. Confusion between 11 locations that were mapped as Coral 10% - \u3c50% were actually Coral 50% - \u3c90% and 1 location mapped as Coral 10% - \u3c50% was found to be Coral 90% - 100%. These sites were all located in the patch reefs of Hawk Channel. It is unknown if these sites met the minimum mapping unit criteria, but the field data indicated high coral cover at these locations. The relatively low adjusted producer’s accuracy for Coral 10% - \u3c50% (55.2%) suggests that not all higher coral cover areas were captured in the map. Furthermore the relatively low user’s accuracy (54.3%) indicates that the areas of Coral 10% - \u3c50% portrayed in the map are highly variable. Combining all the results into a total map accuracy assessment gave a sense of how the overall map portrays the seascape. However, it should be noted that large gaps in map coverage exist, especially between Marathon and Key Largo, a 137 km stretch. The results given in the appendices are more representative of their specific regions. ROIs 1 and 2 covered most of the lower Keys and their results are a good representation of map accuracy for that region. ROI 3 covered the Backcountry which had higher accuracies, presumably due to a reduced diversity of habitats and lack of coral cover. ROI 4 is a good representation of the upper Keys map accuracy. It is difficult to know which assessment best represents the middle Keys. The landscape is more similar to the upper Keys, but Hawk Channel becomes deeper and more turbid

Development of GIS Maps for Southeast Florida Coral Reefs

The present report outlines the results of an integrated mapping project undertaken to provide habitat maps of the shallow Palm Beach County seafloor between the 6m and 35m contours. This study is a continuation of a similar mapping study undertaken in Broward County, and results were produced such that a seamless and fully compatible mapping product is now available for both counties. The study area stretched from 26.4429o (E. Linton Blvd) in the south to 26.9590o (Jupiter Inlet) in the north. Compatibility with other, in particular NOAA, mapping products was also assured. Data types used in this mapping effort included Laser Airborne Depth Sounder (LADS) bathymetry, and single-beam acoustic seafloor discrimination, as well as ecological assessments and groundtruthing. The method used for acoustic seafloor discrimination was based on the first echo and its associated tail, and on the second echo returns of a 38 kHz and a 420 kHz signal. The survey system employed was an at-source-logging Biosonic transducers and Biosonics recording software. Data analysis used QTC Impact software and a suite of in-house custom-developed algorithms that allowed development of an acoustically-based biomass model for gorgonians, algae and barrel sponges (Xestospongia muta). A series of controlled experiments and field verifications verified that it was possible to acoustically distinguish between different scattering classes correlated to different seafloor types and different biomasses of scattering organisms. Two sets of mapping products were produced. In Phase I, polygons were produced by visual interpretation of LADS bathymetry and input of the acoustic ground discrimination. Phase I maps were based on original habitat definitions by the NOAA biogeography program as previously adapted for the Broward County habitat mapping program. The final map showed a well-developed linear reef complex, which is a continuation of the outer reef of Broward County. Also, the middle reef of Broward County was observed in the southern part of Palm Beach County as a linear reef feature. In the northern area of Palm Beach County, a series of hardground ridges, likely a drowned headland, had no equivalent to any structures observed in the other counties. The majority of the area was covered by sand. Distinctions between linear reef, spur and groove, and colonized pavement were based on benthic cover as suggested by acoustic seafloor discrimination and geomorphology. The outer linear reef was subdivided into four habitats: aggregated patch reef, spur and groove, linear reef and deep colonized pavement. The area east of the outer linear reef consisted of a patchy environment with large patches of reef interspersed amongst the deep sand. These were more prevalent close to the reef and tapered off eastward, becoming more sandy. The spur and groove, linear reef, and deep colonized pavement comprised the outer reef and were separated mainly based on geomorphology. The outer reef was separated from the middle linear reef by a wide sand plane (deep sand). Underwater video drop cameras aided in the refinement of the mapping categories. Accuracy assessment of an independent grid of target points showed the Phase I map to have a Users Accuracy of between 85% and 93% and a Producers Accuracy of 89%. These accuracies compare to NOAA published map accuracies. In Phase II, remote ground discrimination based on 38 and 420 kHz acoustic signals was used to map spatial complexity as well as biomass of indicator taxa (gorgonians, macroalgae, barrel sponges). Biomass models of Phase II had accuracies of 79.6% for gorgonians, 61.7% for macroalgae, and 86.1% for barrel sponges (Xestospongia muta). The biomass model derived from the 420 kHz signals agreed with spatial complexity derived from the 38 kHz E1/E2 parameter. The maps show distinct areas of higher biomass alternating with areas of lower biomass within the same habitats. Biomass frequently, but not always, correlated with acoustically derived spatial complexity, which agreed with diving observations and demonstrates the validity of the acoustic ground discrimination. In conclusion, maps of the Palm Beach County’s submarine habitats, with regards to geomorphological zonation and distribution of benthic biomass of certain indicator groups (gorgonians, algae barrel sponges), were produced that were satisfactorily accurate

Experimenter's data package for the descending layers rocket

In response to a proposal from Science Applications International Corporation (SAIC), NASA Headquarters has approved a sounding rocket mission designed to study the physics of intermediate layers in the Earth's ionosphere at middle latitudes. The experiment will be carried out by a team of scientists and engineers from the NASA Wallops Flight Facility, SAIC, the NASA Goddard Space Flight Center, and the Millstone Hill radar observatory. The mission will involve the launch of an instrumented sounding rocket from the Wallops Island rocket range in the summer of 1994, with the objective of penetrating a descending ionized layer in the E-region between altitudes of 115 and 140 km. Instrumentation aboard the rocket will measure the ion and neutral composition of the layer, its plasma density, driving wind and electric field forces, the thermal ion distribution function, and electron temperature. Depending on payload weight constraints and subject to availability, a particle detector to measure energetic ion and/or electron fluxes near the layer may also be included. This document was prepared as a reference for the NASA payload development and experiment teams, for distribution at the Project Initiation Conference (PIC). The design specifications discussed herein are therefore of a preliminary nature; the intent is to promote open discussions between experimenters and NASA engineers that will lead to a final design capable of achieving the experiment objectives

Feeding, tentacle and gut morphology in five species of southern African intertidal holothuroids (Echinodermata)

Light, scanning and transmission electron microscopy were used to compare the structure of the tentacles and digestive tracts of four species of intertidal dendrochlrote (Roweia stephensoni, Pseudocneila sykion, Aslia spyridophora, R. frauenfeldi frauenfeldi),and one species of aspidochirote holothuroid (Neostichopus grammatus). In addition, gut lengths and contents of the five species were compared. Gut contents were sieved to determine the size of the particulate matter ingested. Roweia stephensoni, P. sykion and A. spyridophora were found to be suspension feeders using dendritic tentacles to capture and ingest food particles mostly <53 μm in size. Roweia f. frauenfeldi was also a suspension feeder but, had atypical (reduced) dendritic tentacles which captured food particles between 250 μm-1.18 mm in size. Neostichopus grammatus was a deposit feeder, ingesting sediments mostly between 106-500 μm using tentacles which are peltate with ramified processes. The gut lengths of the four suspension-feeding species were found to be significantly (p <0.001) longer than that of the deposit feeder. The digestive tract of all species was composed of four tissue layers, with the digestive epithelial layer of the anterior and posterior ends of the intestine of suspension feeders being significantly thicker (52 to 57 μm) than that of the deposit feeder (about 19 to 29 μm). In addition, the epithelial layer of the intestine of suspension feeders contained more highly vesicular enterocytes than that of the deposit feeder

The Impact of Changing Technology on the Employment of a Group of Older Deaf Workers

Non

Hydro-mechanical processing of brewer's spent grain as a novel route for separation of protein products with differentiated techno-functional properties

© 2019 Elsevier Ltd Hydro-mechanical processing using a colloid mill with a large gap setting leads to the preferential breakup of the residual aleurone and endosperm tissues of brewer's spent grain, forming a protein rich fines material with small particle size around 1–10 μm. This fraction can be separated from the coarser husk fraction by centrifugation, giving a protein product with enhanced techno-functional properties. The fines have good stability in aqueous suspensions, with potential for stabilising other particulate materials in food or drink formulations. The fines particles can stabilise oil-water emulsions, possibly through a Pickering mechanism, which may also support use in food applications. Fines suspensions have strong shear-thinning behaviour, which may be beneficial from a textural or transport perspective. Spray drying of fines suspensions is shown to avoid particle coalescence, which is important for effective resuspension on rehydration. The high surface area of the fines also leads to more efficient digestion by proteases. Industrial relevance: A novel hydro-mechanical milling process has been investigated for separation of a protein fine fraction from brewer's spent grain having enhanced techno-functional properties. The small particle size of the fines would be a key attribute for formulation in shake or smoothie products, where sensory attributes of the product would not be compromised and the properties of the fines could confer stability against settling. Applications may be found for the fines material as an ingredient in spreads and sauces or infant purees, in-particular where it might be used to stabilise of products based on oil-water emulsions. The market for protein-rich ingredients for foods and drinks is already established in the fitness and well-being market, as derived from other vegetable or cereal sources such as hemp, pea or rice. This controlled pre-milling step is also shown to lead to greater rate and extent of protease digestion of spent grain, which may be of value for generation of protein and peptide products for well-being and cosmetics applications

Development of GIS Maps for Southeast Florida Coral Reefs

The present report outlines the results of an integrated mapping project undertaken to provide a habitat map of the shallow Broward County seafloor between the 0m and 35m contour. The study area stretched from Golden Beach in northern Dade County to just north of the Palm Beach County line. To produce this map and assure its compatibility with other, in particular NOAA, mapping products, a series of data were integrated. Data types included Laser Airborne Depth Sounder (LADS) bathymetry, multi- and single-beam bathymetry, acoustic seafloor discrimination, ecological assessments, and groundtruthing. The method used for acoustic seafloor discrimination was based on the first echo and its associated tail, and on the second echo returns of a 200 kHz signal. Two survey systems were employed: QTC View and Echoplus. A series of controlled experiments and field verifications indicated that it was possible to distinguish acoustically between different scattering classes that correlated to different seafloor types. For the production of the final map, information obtained from LADS bathymetry, NOAA classification and scattering classes obtained by QTC View and Echoplus was fused. The final map showed three well-developed linear reef complexes, a series of deep and shallow ridges believed to be old shorelines, a large sand area between the middle and outer reefs, and a considerable amount of colonized pavement. Due to the lack of distinct geomorphologic zones, the maps were based solely on habitat as defined by the NOAA biogeography program; however distinctions between areas such as linear reef, spur and groove, and colonized pavement were based on benthic cover (as seen by acoustic seafloor discrimination and biological transects) and geomorphology. The outer linear reef was subdivided into four habitats: aggregated patch reef, spur and groove, linear reef and deep colonized pavement. The area east of the outer linear reef consisted of a very patchy environment with large patches of reef interspersed amongst the deep sand. These were more prevalent close to the reef and tapered off eastward, becoming sandier. The spur and groove, linear reef, and deep colonized pavement comprised the outer reef and were separated mainly based on geomorphology. The outer reef was separated from the middle linear reef by a wide sandy plane (deep sand), which was characterized overall by a different scattering class in QTC View than the shallow sand found inshore. Acoustic ground discrimination identified patches of higher scatter and lower scatter amongst the outer, middle, and inner linear reefs suggesting distinct benthic cover between these structures. The eastern boundary of the middle reef was distinct and easily mapped whereas acoustic discrimination aided in determining the western boundary. The inner reef was the least distinct reef as it is not a mature reef. Much of this reef is patchy growth atop an inshore ridge and reef zonation is absent. Acoustic ground discrimination suggested that patches of higher versus lower scatter existed between and within the linear reefs, indicating that dense fauna is patchily distributed. Shoreward of the inner reef, another sand area or a mixture of sand and colonized pavements were found. Several nearshore ridges were mapped that could be classified as linear reef habitat, but were thought to be of non-reefal origin. Therefore these structures were mapped separately even though similar habitat comprises the inshore ridges, the inner linear reef, and the shallow colonized pavements. Excluded habitats such as submerged vegetation and large rubble zones were not detected sufficiently enough to be mapped during this effort. Groundtruthing by way of underwater video drop cameras and in situ biological assessments aided in the refinement of the mapping categories. Accuracy assessment of an independent grid of target points showed the map to have a users accuracy between 83% and 97% and a producers accuracy between 81% and 95%. These are acceptable accuracies and compare similarly to NOAA published map accuracies. In conclusion, the amalgamation of several mapping approaches and data products provided a representative map of Broward County submarine habitats that was accurate to a very satisfactory level. The results of this survey are a good example of how similar mapping products can be attained through different means. The method employed to map Broward County appears to have equally and accurately illustrated the benthic community as more traditional methods like photo interpretation. Similar methodology should be used in other areas where photo interpretation is not feasible due to either absence of data or the turbidity of the water

Online privacy fatigue:a scoping review and research agenda

Online users are responsible for protecting their online privacy themselves: the mantra is custodiat te (protect yourself). Even so, there is a great deal of evidence pointing to the fact that online users generally do not act to preserve the privacy of their personal information, consequently disclosing more than they ought to and unwisely divulging sensitive information. Such self-disclosure has many negative consequences, including the invasion of privacy and identity theft. This often points to a need for more knowledge and awareness but does not explain why even knowledgeable users fail to preserve their privacy. One explanation for this phenomenon may be attributed to online privacy fatigue. Given the importance of online privacy and the lack of integrative online privacy fatigue research, this scoping review aims to provide researchers with an understanding of online privacy fatigue, its antecedents and outcomes, as well as a critical analysis of the methodological approaches used. A scoping review based on the PRISMA-ScR checklist was conducted. Only empirical studies focusing on online privacy were included, with nontechnological studies being excluded. All studies had to be written in English. A search strategy encompassing six electronic databases resulted in eighteen eligible studies, and a backward search of the references resulted in an additional five publications. Of the 23 studies, the majority were quantitative (74%), with fewer than half being theory driven (48%). Privacy fatigue was mainly conceptualized as a loss of control (74% of studies). Five categories of privacy fatigue antecedents were identified: privacy risk, privacy control and management, knowledge and information, individual differences, and privacy policy characteristics. This study highlights the need for greater attention to be paid to the methodological design and theoretical underpinning of future research. Quantitative studies should carefully consider the use of CB-SEM or PLS-SEM, should aim to increase the sample size, and should improve on analytical rigor. In addition, to ensure that the field matures, future studies should be underpinned by established theoretical frameworks. This review reveals a notable absence of privacy fatigue research when modeling the influence of privacy threats and invasions and their relationship with privacy burnout, privacy resignation, and increased self-disclosure. In addition, this review provides insight into theoretical and practical research recommendations that future privacy fatigue researchers should consider going forward