Polycyclic musk compounds in higher trophic level aquatic organisms and humans from the United States

Polycyclic musks, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), are used as fragrance ingredients in numerous consumer products such as cleaning agents and personal care products. Studies have reported the widespread occurrence of these musks in surface waters and fish from western European countries. Nevertheless, little is known about their accumulation in humans and wildlife in the United States. In this study, we measured concentrations of HHCB and AHTN in human adipose fat collected from New York City. Furthermore, tissues from marine mammals, water birds, and fish collected from US waters were analyzed to determine the concentrations of HHCB and AHTN. Concentrations of HHCB and AHTN in human adipose fat samples ranged from 12 to 798 and from <5 to 134 ng/g, on a lipid weight basis, respectively. A significant correlation existed between the concentrations of HHCB and AHTN in human adipose fat. Concentrations of HHCB and AHTN were not positively correlated with age or gender of the donors. HHCB was found in tissues of several wildlife species, but not in the livers of polar bear from the Alaskan Arctic. Among wildlife species analyzed, spinner and bottlenose dolphins collected from Florida coastal waters contained measurable concentrations of HHCB.     

Linking the brown and green: nutrient transformation and fate in the Sarracenia microecosystem

Linkages between detritus-based ("brown") food webs and producer-based ("green") food webs are critical components of ecosystem functionality, but these linkages are hard to study because it is difficult to measure release of nutrients by brown food webs and their subsequent uptake by plants. In a three-month greenhouse experiment, we examined how the detritus-based food web inhabiting rain-filled leaves of the pitcher plant Sarracenia purpurea affects nitrogen transformation and its subsequent uptake by the plant itself. We used isotopically enriched prey (detritus) and soluble inorganic nitrogen, and manipulated food web structure to determine whether the presence of a complete brown web influences uptake efficiency of nitrogen by the plant. Uptake efficiency of soluble inorganic nitrogen was greater than that of nitrogen derived from mineralized prey. Contrary to expectation, there was no effect of the presence in the food web of macroinvertebrates on uptake efficiency of either form of nitrogen. Further, uptake efficiency of prey-derived nitrogen did not differ significantly among S. purpurea and two congeneric species (S. flava and S. alata) that lack associated food webs. Although upper trophic levels of this brown food web actively process detritus, it is the activity of the microbial component of this web that ultimately determines nitrogen availability for S. purpurea.     

Spatial and temporal variation in distribution and protein ubiquitination for <Emphasis Type="Italic">Mytilus</Emphasis> congeners in the California hybrid zone

Along the west coast of North America, the invasive mussel Mytilus galloprovincialis and a native congener M. trossulus overlap in range and compete for habitat in an extensive hybrid zone along central California. The two species have been shown to exhibit differential abiotic tolerances in laboratory studies, yet little is known about how such tolerances affect spatial and temporal patterns of geographic distribution, particularly in areas of competition. We examined distributions of the two congeners and their hybrids in neighboring intertidal and subtidal habitats in Bodega Bay, CA over 2 years, and compared shell length and seasonal ubiquitin (Ub) conjugates to estimate protein turnover and physiological stress for the species at each site. The two species were spatially segregated, with M. galloprovincialis dominating the subtidal habitat, and M. trossulus constituting a majority of the intertidal mussel population. Hybrid individuals appeared in low numbers at both sites. For each habitat, there was no statistical difference between shell lengths of M. galloprovincialis and hybrids but M. trossulus mussels were statistically smaller than the other two. In regards to physiological performance, ubiquitin conjugate values showed different seasonal cycles for the two species, suggesting different periods of peak environmental stress. The highest levels of Ub-conjugated proteins were observed in winter for M. galloprovincialis and in summer for M. trossulus, consistent with the respective range edges for their distributions since Bodega Bay is near the northern range edge of the invader and the southern edge of the native species. These findings suggest that future assessments of Mytilus populations along the California coast may need to consider vertical distributions and seasonal cycles as part of monitoring and research activities.     

The scope and severity of white-nose syndrome on hibernating bats in North America

Assessing the scope and severity of threats is necessary for evaluating impacts on populations to inform conservation planning. Quantitative threat assessment often requires monitoring programs that provide reliable data over relevant spatial and temporal scales, yet such programs can be difficult to justify until there is an apparent stressor. Leveraging efforts of wildlife management agencies to record winter counts of hibernating bats, we collated data for 5 species from over 200 sites across 27 U.S. states and 2 Canadian provinces from 1995 to 2018 to determine the impact of white-nose syndrome (WNS), a deadly disease of hibernating bats. We estimated declines of winter counts of bat colonies at sites where the invasive fungus that causes WNS (Pseudogymnoascus destructans) had been detected to assess the threat impact of WNS. Three species undergoing species status assessment by the U.S. Fish and Wildlife Service (Myotis septentrionalis, Myotis lucifugus, and Perimyotis subflavus) declined by more than 90%, which warrants classifying the severity of the WNS threat as extreme based on criteria used by NatureServe. The scope of the WNS threat as defined by NatureServe criteria was large (36% of Myotis lucifugus range) to pervasive (79% of Myotis septentrionalis range) for these species. Declines for 2 other species (Myotis sodalis and Eptesicus fuscus) were less severe but still qualified as moderate to serious based on NatureServe criteria. Data-sharing across jurisdictions provided a comprehensive evaluation of scope and severity of the threat of WNS and indicated regional differences that can inform response efforts at international, national, and state or provincial jurisdictions. We assessed the threat impact of an emerging infectious disease by uniting monitoring efforts across jurisdictional boundaries and demonstrated the importance of coordinated monitoring programs, such as the North American Bat Monitoring Program (NABat), for data-driven conservation assessments and planning.     

Status of Southeast Asia's marine sharks and rays

In Southeast Asia, elasmobranchs are particularly threatened. We synthesized knowledge from the peer-reviewed and gray literature on elasmobranchs in the region, including their fisheries, status, trade, biology, and management. We found that 59% of assessed species are threatened with extinction and 72.5% are in decline; rays were more threatened than sharks. Research and conservation is complicated by the socioeconomic contexts of the countries, geopolitical issues in the South China Sea, and the overcapacity and multispecies nature of fisheries that incidentally capture elasmobranchs. The general paucity of data, funds, personnel, and enforcement hinders management. Reduced capacity in the general fishery sector and marine protected areas of sufficient size (for elasmobranchs and local enforcement capabilities) are among recommendations to strengthen conservation.     

Determination of polychlorinated biphenyl congeners in sediment samples of twelve rivers in eastern China

Polychlorinated biphenyl (PCB) congener concentrations and their distributions were determined for the first time in 12 major rivers of eastern China. It was found that the PCB contamination level in those rivers was relatively low compared to the levels reported in most developing countries. Total amount of PCBs in the river sediments ranged from 10 to 22 ng/g dry weight and dichlorodiphenyldichloroethene (DDE) ranged from 0.89 to 7.62 ng/g. The PCB concentrations were basically homogeneous in different rivers; however, they consistently changed with the percent of total organic carbon (TOC). The PCB concentrations and compositions found in the 12 river sediments were very similar, with the tetra‐ and penta‐ groups as the dominants. Given that distributions and contaminant levels in sediments reflect the number of PCBs, the contamination of the 12 major rivers in eastern China is probably due to atmospheric deposition rather than the point source contamination.     

Ranging behavior of the mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda: a test of the ecological constraints model

The ecological constraints model predicts that daily travel distance and home range size of social animals will increase as group size increases in order to meet the dietary needs of additional group members. This theory has been supported more predominantly by studies of frugivorous primate species than by studies of folivorous species. We examined the ranging patterns of mountain gorillas in Bwindi Impenetrable National Park, Uganda, who include both herbaceous vegetation and fruit in their diet, to determine how ecological, behavioral, and social parameters influence movement patterns. Data were collected from three groups of gorillas with overlapping home ranges at a low-altitude location (1,450–1,800 m) and one group at a high-altitude location (2,100–2,500 m) in Bwindi from September 2001 to August 2002. We analyzed daily travel distance and home range size in relation to group size, while also considering patterns of frugivory, rainfall, and location (proxy for food availability) within the park. Both daily travel distance and home range size were positively related to group size. In addition, the degree of frugivory positively influenced daily travel distance and home range size, while rainfall negatively influenced daily travel distance only. Finally, groups at the low-altitude location, with higher fruit availability, traveled less than the group at the high-altitude location. These results demonstrate that mountain gorillas in Bwindi provide support for the ecological constraints model, but further studies are needed to determine how fine-scale spatial and temporal availability of food resources influence movement patterns. Ranging patterns of Bwindi gorillas are compared to those observed in other gorilla populations in the context of the ecological constraints model.Communicated by D. Watts     

Impact of cigarette smoking on volatile organic compound (VOC) blood levels in the U.S. population: NHANES 2003-2004

The impact of cigarette smoking on volatile organic compound (VOC) blood levels is studied using 2003-2004 National Health and Nutrition Examination Survey (NHANES) data. Cigarette smoke exposure is shown to be a predominant source of benzene, toluene, ethylbenzene, xylenes and styrene (BTEXS) measured in blood as determined by (1) differences in central tendency and interquartile VOC blood levels between daily smokers [≥1 cigarette per day (CPD)] and less-than-daily smokers, (2) correlation among BTEXS and the 2,5-dimethylfuran (2,5-DMF) smoking biomarker in the blood of daily smokers, and (3) regression modeling of BTEXS blood levels versus categorized CPD. Smoking status was determined by 2,5-DMF blood level using a cutpoint of 0.014 ng/ml estimated by regression modeling of the weighted data and confirmed with receiver operator curve (ROC) analysis. The BTEXS blood levels among daily smokers were moderately-to-strongly correlated with 2,5-DMF blood levels (correlation coefficient, r, ranging from 0.46 to 0.92). Linear regression of the geometric mean BTEXS blood levels versus categorized CPD showed clear dose-response relationship (correlation of determination, R(2), ranging from 0.81 to 0.98). Furthermore, the pattern of VOCs in blood of smokers is similar to that reported in mainstream cigarette smoke. These results show that cigarette smoking is a primary source of benzene, toluene and styrene and an important source of ethylbenzene and xylene exposure for the U.S. population, as well as the necessity of determining smoking status and factors affecting dose (e.g., CPD, time since last cigarette) in assessments involving BTEXS exposure.     

Exploring relationships between observed activation rates and functional attributes of lane departure prevention

Objective: Drivers’ use of lane departure warning and prevention systems is lower than use of other crash avoidance technologies and varies significantly by manufacturer. One factor that may affect use is how well a system prevents unintended departures. The current study evaluated the performance of systems that assist in preventing departures by providing steering or braking input in a 2016 Chevrolet Malibu, 2016 Ford Fusion, 2016 Honda Accord, and 2018 Volvo S90. These vehicles were selected because a prior observational study found that the percentage of privately owned vehicles that had lane departure prevention systems turned on varied among these 4 automakers.

Method: In each vehicle, a test driver induced 40 lane drifts on left and right curves by steering the vehicle straight into the curve so that vehicles departed in the opposite direction and 40 lane drifts on straightaways by slight steering input to direct the vehicle to left and right lane markers.

Results: Vehicles from automakers with higher observed lane departure prevention use rates (Volvo, Chevrolet) featured systems that provided steering input earlier and more often avoided crossing lane markers by more than 35?cm compared to vehicles from automakers with lower observed use rates (Ford, Honda).

Conclusion: The study identified functional characteristics (i.e., timing of steering input, prevention of departures more than 35?cm) of lane departure prevention systems that were strongly associated with observed activation of these systems in privately owned vehicles. Although this relationship does not imply causation, the findings support the hypothesis that functional characteristics of lane departure prevention systems affect their use. Designers may be able to use these results to maximize driver acceptance of future implementations of lane departure prevention.