Probability sampling of stony coral populations in the Florida Keys

Principles of probability survey design were applied to guide large-scale sampling of populations of stony corals and associated benthic taxa in the Florida Keys coral reef ecosystem. The survey employed a two-stage stratified random sampling design that partitioned the 251-km(2) domain by reef habitat types, geographic regions, and management zones. Estimates of the coefficient of variation (ratio of standard error to the mean) for stony coral population density and abundance ranged from 7% to 12% for four of six principal species. These levels of survey precision are among the highest reported for comparable surveys of marine species. Relatively precise estimates were also obtained for octocoral density, sponge frequency of occurrence, and benthic cover of algae and invertebrates. Probabilistic survey design techniques provided a robust framework for estimating population-level metrics and optimizing sampling efficiency.     

The relative importance of COVID-19 pandemic impacts on biodiversity conservation globally

The COVID-19 pandemic has had an enormous impact on almost all aspects of human society and endeavor; the natural world and its conservation have not been spared. Through a process of expert consultation, we identified and categorized, into 19 themes and 70 subthemes, the ways in which biodiversity and its conservation have been or could be affected by the pandemic globally. Nearly 60% of the effects have been broadly negative. Subsequently, we created a compendium of all themes and subthemes, each with explanatory text, and in August 2020 a diverse group of experienced conservationists with expertise from across sectors and geographies assessed each subtheme for its likely impact on biodiversity conservation globally. The 9 subthemes ranked highest all have a negative impact. These were, in rank order, governments sidelining the environment during their economic recovery, reduced wildlife-based tourism income, increased habitat destruction, reduced government funding, increased plastic and other solid waste pollution, weakening of nature-friendly regulations and their enforcement, increased illegal harvest of wild animals, reduced philanthropy, and threats to survival of conservation organizations. In combination, these impacts present a worrying future of increased threats to biodiversity conservation but reduced capacity to counter them. The highest ranking positive impact, at 10, was the beneficial impact of wildlife-trade restrictions. More optimistically, among impacts ranked 11-20, 6 were positive and 4 were negative. We hope our assessment will draw attention to the impacts of the pandemic and, thus, improve the conservation community's ability to respond to such threats in the future.     

Modeling the Fate and Transport of Plunging Inflows to Onondaga Lake

The transport and fate of two plunging tributaries, Onondaga and Ninemile Creeks, in Onondaga Lake, New York, are quantified based on application of hydrodynamic/transport models. Short‐term transport is simulated with a three‐dimensional Estuary Lake and Coastal Ocean Model (ELCOM), while the longer term fate is represented by a previously validated one‐dimensional model (UFILS4). The validation of ELCOM for the vertical distribution of tributary inflow into the lake's water column is demonstrated for four dye tracer experiments. The models are applied for three years to represent the dynamics of transport and fate for the two tributaries, with ELCOM predictions serving as input for UFILS4. The models together quantify the distribution of these inflows between the upper mixed layer (UML) and stratified depths, and the subsequent transport from stratified depths to the UML by vertical mixing. Substantial short‐term variations are predicted for both tributaries in response to variability in hydrology and weather. Increased inflow to the UML is predicted for high runoff periods. The fraction of Ninemile Creek's inflow directly entering the UML is predicted to be 50% greater than for Onondaga Creek due to Ninemile's lower negative buoyancy. The plunging phenomenon has important water quality implications, by reducing the effective loading to the UML, particularly for constituents with large rates of loss/transformation relative to the rate of vertical transport from stratified depths.     

Toxicity of emerging energetic soil contaminant CL-20 to potworm Enchytraeus crypticus in freshly amended or weathered and aged treatments

We investigated the toxicity of an emerging polynitramine energetic material hexanitrohexaazaisowurtzitane (CL-20) to the soil invertebrate species Enchytraeus crypticus by adapting then using the Enchytraeid Reproduction Test (ISO/16387:2003). Studies were designed to develop ecotoxicological benchmark values for ecological risk assessment of the potential impacts of accidental release of this compound into the environment. Tests were conducted in Sassafras Sandy Loam soil, which supports relatively high bioavailability of CL-20. Weathering and aging procedures for CL-20 amended into test soil were incorporated into the study design to produce toxicity data that better reflect soil exposure conditions in the field compared with the toxicity in freshly amended soils. Concentration-response relationships for measurement endpoints were determined using nonlinear regressions. Definitive tests showed that toxicities for E. crypticus adult survival and juvenile production were significantly increased in weathered and aged soil treatments compared with toxicity in freshly amended soil, based on 95% confidence intervals. The median effect concentration (EC50) and EC20 values for juvenile production were 0.3 and 0.1 mg kg-1, respectively, for CL-20 freshly amended into soil, and 0.1 and 0.035 mg kg-1, respectively, for weathered and aged CL-20 soil treatments. These findings of increased toxicity to E. crypticus in weathered and aged CL-20 soil treatments compared with exposures in freshly amended soils show that future investigations should include a weathering and aging component to generate toxicity data that provide more complete information on ecotoxicological effects of emerging energetic contaminants in soil.     

Dark, bitter-tasting nectar functions as a filter of flower visitors in a bird-pollinated plant

Floral nectar is offered by plants to animals as a reward for pollination. While nectar is typically a clear liquid containing sugar and trace amounts of amino acids, colored nectar has evolved in several plant families. Here we explore the functional significance of the phenolic compounds that impart a dark brown color to the nectar of the South African succulent shrub Aloe vryheidensis. Flowers of this aloe are visited for their nectar by a suite of short-billed birds that are occasional nectarivores, including bulbuls, white-eyes, rock thrushes, and chats. Dark-capped Bulbuls were more likely to probe model flowers containing dark nectar than those containing clear nectar, suggesting a potential signaling function for dark nectar. However, the main effect of the phenolics appears to be to repel "unwanted" nectarivores that find their bitter taste unpalatable. Nectar-feeding honey bees and sunbirds are morphologically mismatched for pollinating A. vryheidensis flowers and strongly reject its nectar. However, the frugivorous and insectivorous birds that effectively pollinate this aloe are seemingly unaffected by the nectar's bitter taste. Thus the dark phenolic component of the nectar appears to function as a floral filter by attracting some animals visually and deterring others by its taste.     

Development of injury criteria for pelvic fracture in frontal crashes

OBJECTIVE: This article assesses the position-dependent injury tolerance of the hip in the frontal direction based on testing of eight postmortem human subjects. METHODS: For each subject, the left and right hemipelvis complex was axially loaded using a previously developed test configuration. Six positions were defined from a seated femur neutral condition, combining flexed, neutral, and extended femur positions with abducted, neutral, and adducted positions. RESULTS: Axial injury tolerances based on peak force were found to be 6,850 +/- 840 N in the extended, neutral position and 4,080 +/- 830 N in the flexed, neutral position. From the flexed neutral orientation, the peak axial force increased 18% for 20 degrees abduction and decreased 6% for 20 degrees adduction. From the extended, neutral orientation, the peak axial force decreased 4% for 20 degrees abduction and decreased 3% for 20 degrees adduction. However, as there is evidence that increases in loading may occur after the initiation of fracture, the magnitude of the peak force is likely related to the extent of injury, not to the initial tolerance. Using the axial femur force at the initiation of fracture (assessed with acoustic crack sensors) as a potentially more relevant indicator of injury may lower the existing injury criteria. This fracture initiation force varied by position from 3,010 +/- 560 N in the flexed, neutral position to 5,470 N in the extended, abducted position. Further, there was a large position-dependent variation in the ratio of fracture initiation force to the peak axial force. The initiation of fracture was 83% of the peak axial force in the extended, abducted position, but the ratio was 34% in the extended, adducted position. CONCLUSIONS: This may have significant implications for the development of pelvic injury criteria by automobile designers attempting to mitigate pelvis injuries.     

Comparison of measured total suspended particulate matter concentrations using tapered element oscillating microbalance and a total suspended particulate sampler

A comparison of the concentration of the total suspended particulate (TSP) matter measured by the tapered element oscillating microbalance (TEOM) monitor and the isokinetic TSP samplers developed at the University of Illinois was carried out in several types of confinement livestock buildings. In a majority of the measurements done, the dust concentration measured by the TEOM monitor was lower than the University of Illinois at Urbana-Champaign (UIUC) isokinetic TSP sampler; the TEOM monitor tended to underestimate the total dust concentration by as much as 54%. The difference in measurements can be attributed to the sampling efficiency of the TEOM monitor sampling head and the loss of some semivolatile compounds and particle-bound water because of heating of the TEOM monitor sampling stream to 50 degrees C. Although several articles in the literature supported the latter argument, this study did not investigate the effect of heating the sampling stream or the effect of moisture on the relative difference in dust concentration measurements. The model that best describes the relationship between the two methods was site specific, that is, the linear regression model was applicable only to four of the sites monitored. The measured total dust concentration in livestock buildings range from approximately 300 to 4000 microg/m3; a higher correlation coefficient between TEOM-TSP and UIUC-TSP monitors was obtained in swine facilities than those obtained in a laying facility.     

Processes influencing secondary aerosol formation in the San Joaquin Valley during winter

Air quality data collected in the California Regional PM10/ PM(2.5) Air Quality Study (CRPAQS) are analyzed to qualitatively assess the processes affecting secondary aerosol formation in the San Joaquin Valley (SJV). This region experiences some of the highest fine particulate matter (PM(2.5)) mass concentrations in California (< or = 188 microg/m3 24-hr average), and secondary aerosol components (as a group) frequently constitute over half of the fine aerosol mass in winter. The analyses are based on 15 days of high-frequency filter and canister measurements and several months of wintertime continuous gas and aerosol measurements. The phase-partitioning of nitrogen oxide (NO(x))-related nitrogen species and carbonaceous species shows that concentrations of gaseous precursor species are far more abundant than measured secondary aerosol nitrate or estimated secondary organic aerosols. Comparisons of ammonia and nitric acid concentrations indicate that ammonium nitrate formation is limited by the availability of nitric acid rather than ammonia. Time-resolved aerosol nitrate data collected at the surface and on a 90-m tower suggest that both the daytime and nighttime nitric acid formation pathways are active, and entrainment of aerosol nitrate formed aloft at night may explain the spatial homogeneity of nitrate in the SJV. NO(x) and volatile organic compound (VOC) emissions plus background O3 levels are expected to determine NO(x) oxidation and nitric acid production rates, which currently control the ammonium nitrate levels in the SJV. Secondary organic aerosol formation is significant in winter, especially in the Fresno urban area. Formation of secondary organic aerosol is more likely limited by the rate of VOC oxidation than the availability of VOC precursors in winter.     

Wintertime vertical variations in particulate matter (PM) and precursor concentrations in the San Joaquin Valley during the California Regional Coarse PM/Fine PM Air Quality Study

Air quality monitoring was conducted at a rural site with a tower in the middle of California's San Joaquin Valley (SJV) and at elevated sites in the foothills and mountains surrounding the SJV for the California Regional PM10/ PM2.5 Air Quality Study. Measurements at the surface and n a tower at 90 m were collected in Angiola, CA, from December 2000 through February 2001 and included hourly black carbon (BC), particle counts from optical particle counters, nitric oxide, ozone, temperature, relative humidity, wind speed, and direction. Boundary site measurements were made primarily using 24-hr integrated particulate matter (PM) samples. These measurements were used to understand the vertical variations of PM and PM precursors, the effect of stratification in the winter on concentrations and chemistry aloft and at the surface, and the impact of aloft-versus-surface transport on PM concentrations. Vertical variations of concentrations differed among individual species. The stratification may be important to atmospheric chemistry processes, particularly nighttime nitrate formation aloft, because NO2 appeared to be oxidized by ozone in the stratified aloft layer. Additionally, increases in accumulation-mode particle concentrations in the aloft layer during a fine PM (PM2.5) episode corresponded with increases in aloft nitrate, demonstrating the likelihood of an aloft nighttime nitrate formation mechanism. Evidence of local transport at the surface and regional transport aloft was found; transport processes also varied among the species. The distribution of BC appeared to be regional, and BC was often uniformly mixed vertically. Overall, the combination of time-resolved tower and surface measurements provided important insight into PM stratification, formation, and transport.     

Measurement and modeling of urban atmospheric PCB concentrations on a small (8 km) spatial scale

Atmospheric transport and deposition of polychlorinated biphenyls (PCBs) is an important problem for ecosystems around the world. Data from several monitoring networks demonstrate that atmospheric PCB concentrations are dramatically elevated in urban areas compared to rural or background regions, such that these urban emissions of PCBs support the regional and global transport and deposition of PCBs to more remote areas. Identifying and controlling the sources of urban atmospheric PCBs is thus essential in minimizing the regional and global transport and deposition of these compounds. From December 1999 to November 2000, gas-phase PCB concentrations were measured at two monitoring locations, 8 km apart, within the New York City metropolitan area, at Jersey City and Bayonne, NJ. Concentrations, congener patterns, and temporal patterns of PCBs differ dramatically at the two sites, suggesting that a significant source of atmospheric PCBs exists within 8 km of the Bayonne site, resulting in spikes in gas-phase PCB concentration at Bayonne that are not observed at Jersey City. The Regional Atmospheric Model System (RAMS) coupled with the Hybrid Particle and Concentration Transport model (HYPACT) was used to estimate that the PCB source near Bayonne emits a flux of ΣPCBs on the order of 100 g d⁻¹. Extrapolation of this source magnitude to the area of New York City suggests that this urban area emits at least 300 kg yr⁻¹ ΣPCBs to the regional atmosphere, similar in magnitude to the flow of ΣPCB out of the Upper Hudson River into the New York/New Jersey Harbor.