Morphological adaptations to chronic hypoxia in deep-sea decapod crustaceans from hydrothermal vents and cold seeps

Animals inhabiting hydrothermal vents and cold seeps face conditions that are challenging for survival. In particular, these two habitats are characterized by chronic hypoxia, sometimes reaching complete anoxia. The characteristics of the scaphognathite and gills were studied in four species of shrimp and three species of crabs from hydrothermal vents and cold seeps, in order to highlight potential adaptations that could enhance oxygen acquisition in comparison with shallow-water relatives. All the vent and seep species studied here exhibit significantly larger scaphognathites, likely allowing more water to flow over their gills per stroke of this appendage. This is probably more energetically efficient that prolonged hyperventilation. In contrast to annelids, vent and seep decapods usually do not possess enlarged gills, a phenomenon likely due to the physical limitations imposed by the size of the gill chamber. In the vent shrimp Rimicaris exoculata and the vent crab Bythograea thermydron, however, there is a significantly higher specific gill surface area linked to a higher number of lamellae per gram of gill. Again in contrast to annelids, the diffusion distance through the gills is not strikingly different between the vent shrimp Alvinocaris komaii and the shallow-water species Palaemon spp. This may indicate that the epithelium and cuticle of the decapod gills are already optimized for oxygen uptake and that reducing the thickness of these compartments is not physically possible without affecting the physical integrity of the gills.     

The cost of sexual coercion and heterospecific sexual harassment on the fecundity of a host-specific, seed-eating insect (Neacoryphus bicrucis)

Two species of seed-eating true bugs, Neacoryphus bicrucis (Heteroptera: Lygaeidae) and Margus obscurator (Heteroptera: Coreidae) co-occur on ragwort, Senecio tomentosus, in southern Georgia, USA. Males of both species sometimes engage in chases and protracted grappling with females that flee initial mountings. Sometimes genital coupling occurs while the wriggling female is restrained in the male's grasp. Chases, grappling, and mounting attempts are misdirected toward heterospecific females, heterospecific males, or conspecific males. In a laboratory study, confinement of mated N. bicrucis females with either conspecific or heterospecific males reduced fecundity by approximately one-half relative to mated females confined only with other females. Perhaps as a consequence of this, N. bicrucis females frequently leave areas of high host plant density, where they prefer to oviposit, when males are abundant. The abundance of each species is positively correlated with host plant density but the two species rarely occur together on the same plants. This may be an effect of heterospecific courtship which induces the flight of N. bicrucis more than the flight of M. obscurator. The laboratory results suggest that copulations following chases and grappling represent sexual harassment, not a mechanism of active female choice for a vigorous mate. As sexual harassment imposes high fitness costs that favor abandonment of host plants, it may, when misdirected, incidentally limit habitat use by ecologically similar species. Received: 3 October 1998 / Received in revised form: 21 January 1999 / Accepted: 14 February 1999     

Changes in fall prevention training for apprentice carpenters based on a comprehensive needs assessment

Problem

Falls from heights in residential construction are common, especially among inexperienced workers.

Methods

We conducted a comprehensive needs assessment to determine gaps in the school-based apprentice carpenters' fall prevention training. A team of carpenter instructors and researchers revised the fall prevention training to fill these gaps. Apprentice evaluation and feedback guided ongoing curricular improvements.

Results

Most apprentice carpenters performed work tasks at heights prior to training and fall protection techniques were not commonly used at residential construction sites. Priorities of the revised school-based training included safe ladder habits, truss setting, scaffold use, guarding floor openings, and using personal fall arrest systems. New apprentices were targeted to ensure training prior to exposure at the workplace. We used adult learning principles to emphasize hands-on experiences. A framed portion of a residential construction site was fabricated to practice fall protection behaviors in a realistic setting. The revised curriculum has been delivered consistently and apprentice feedback has been very favorable.

Conclusions

Integration of needs assessment results was invaluable in revising the school-based carpenters apprentice fall prevention curriculum. Working closely with the instructors to tailor learning experiences has provided preliminary positive results.

Impact on Industry

The fall safety of the residential construction industry continues to lag behind commercial construction and industrial settings. The National Occupational Research Agenda includes a Strategic Goal to strengthen and extend the reach of quality training and education in the construction industry via mechanisms such as construction safety and health training needs assessments. This study demonstrates how a structured process can be used to identify and remedy gaps and improve training effectiveness. We encourage others to take steps to assess and increase the impact of training efforts directed at all residential construction professionals; including both union and non-union workers. The implications are even greater in the non-union sector where most U.S. residential work is done.     

Protection of wetlands as a strategy for reducing the spread of avian influenza from migratory waterfowl

Highly pathogenic avian influenza (HPAI) H5N1 has led to the death or destruction of millions of domesticated and wild birds and caused hundreds of human deaths worldwide. As with other HPAIs, H5N1 outbreaks among poultry have generally been caused by contact with infected migratory waterfowl at the interface of wildlands and human-dominated landscapes. Using a case–control epidemiological approach, we analyzed the relation between habitat protection and H5N1 outbreaks in China from 2004 to 2017. We found that while proximity to unprotected waterfowl habitats and rice paddy generally increased outbreak risk, proximity to the most highly protected habitats (e.g., Ramsar-designated lakes and wetlands) had the opposite effect. Protection likely involves two mechanisms: the separation of wild waterfowl and poultry populations and the diversion of wild waterfowl from human-dominated landscapes toward protected natural habitats. Wetland protection could therefore be an effective means to control avian influenza while also contributing to avian conservation.     

A Decision Support Framework for Science-Based, Multi-Stakeholder Deliberation: A Coral Reef Example

We present a decision support framework for science-based assessment and multi-stakeholder deliberation. The framework consists of two parts: a DPSIR (Drivers–Pressures–States–Impacts–Responses) analysis to identify the important causal relationships among anthropogenic environmental stressors, processes, and outcomes; and a Decision Landscape analysis to depict the legal, social, and institutional dimensions of environmental decisions. The Decision Landscape incorporates interactions among government agencies, regulated businesses, non-government organizations, and other stakeholders. It also identifies where scientific information regarding environmental processes is collected and transmitted to improve knowledge about elements of the DPSIR and to improve the scientific basis for decisions. Our application of the decision support framework to coral reef protection and restoration in the Florida Keys focusing on anthropogenic stressors, such as wastewater, proved to be successful and offered several insights. Using information from a management plan, it was possible to capture the current state of the science with a DPSIR analysis as well as important decision options, decision makers and applicable laws with a the Decision Landscape analysis. A structured elicitation of values and beliefs conducted at a coral reef management workshop held in Key West, Florida provided a diversity of opinion and also indicated a prioritization of several environmental stressors affecting coral reef health. The integrated DPSIR/Decision landscape framework for the Florida Keys developed based on the elicited opinion and the DPSIR analysis can be used to inform management decisions, to reveal the role that further scientific information and research might play to populate the framework, and to facilitate better-informed agreement among participants.     

Sustainable Development in an N-Rich/N-Poor World

Sustainable development requires that per capita inclusive wealth—produced, human, and natural capital—does not decline over time. We investigate the impact of changes in nitrogen on inclusive wealth. There are two sides to the nitrogen problem. Excess use of nitrogen in some places gives rise to N-pollution, which can cause environmental damage. Insufficient replacement of nitrogen in other places gives rise to N-depletion, or loss of nutrient stocks. Neither is explicitly accounted for in current wealth measures, but both affect wealth. We calculate an index of net N-replacement, and investigate its relationship to wealth. In countries with low levels of relative N-loss, we find that the uncompensated loss of soil nitrogen in poorer countries is associated with declining rates of growth of inclusive per capita wealth. What is less intuitive is that increasing fertilizer application in both rich and poor countries can increase per capita inclusive wealth.     

Metal mobilization in soil by two structurally defined polyphenols

Polyphenols including tannins comprise a large percentage of plant detritus such as leaf litter, and affect soil processes including metal dynamics. We tested the effects of tannins on soil metal mobilization by determining the binding stoichiometries of two model polyphenols to Al(III) and Fe(III) using micelle-mediated separation and inductively coupled plasma optical emission spectroscopy (ICP-OES). By fitting the data to the Langmuir model we found the higher molecular weight polyphenol (oenothein B) was able to bind more metal than the smaller polyphenol (epigallocatechin gallate, EGCg). For example, oenothein B bound 9.43 mol Fe mol^?1, while EGCg bound 4.41 mol of Fe mol^?1. Using the parameters from the binding model, we applied the Langmuir model for competitive binding to predict binding for mixtures of Al(III) and Fe(III). Using the parameters from the single metal experiments and information about polyphenol sorption to soils we built a model to predict metal mobilization from soils amended with polyphenols. We tested the model with three natural soils and found that it predicted mobilization of Fe and Al with r² = 0.92 and r² = 0.88, respectively. The amount of metal that was mobilized was directly proportional to the maximum amount of metal bound to the polyphenol. The secondary parameter in each model was the amount of weak organically chelated Fe or Al that was in the soil. This study provides the first compound-specific information about how natural polyphenols interact with metals in the environment. We propose a model that is applicable to developing phytochelation agents for metal detoxification, and we discuss how tannins may play a role in metal mobilization from soils.     

Comparison of total mercury and methylmercury cycling at five sites using the small watershed approach

The small watershed approach is well-suited but underutilized in mercury research. We applied the small watershed approach to investigate total mercury (THg) and methylmercury (MeHg) dynamics in streamwater at the five diverse forested headwater catchments of the US Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) program. At all sites, baseflow THg was generally less than 1ng L(-1) and MeHg was less than 0.2ng L(-1). THg and MeHg concentrations increased with streamflow, so export was primarily episodic. At three sites, THg and MeHg concentration and export were dominated by the particulate fraction in association with POC at high flows, with maximum THg (MeHg) concentrations of 94 (2.56)ng L(-1) at Sleepers River, Vermont; 112 (0.75)ng L(-1) at Rio Icacos, Puerto Rico; and 55 (0.80)ng L(-1) at Panola Mt., Georgia. Filtered (<0.7microm) THg increased more modestly with flow in association with the hydrophobic acid fraction (HPOA) of DOC, with maximum filtered THg concentrations near 5ng L(-1) at both Sleepers and Icacos. At Andrews Creek, Colorado, THg export was also episodic but was dominated by filtered THg, as POC concentrations were low. MeHg typically tracked THg so that each site had a fairly constant MeHg/THg ratio, which ranged from near zero at Andrews to 15% at the low-relief, groundwater-dominated Allequash Creek, Wisconsin. Allequash was the only site with filtered MeHg consistently above detection, and the filtered fraction dominated both THg and MeHg. Relative to inputs in wet deposition, watershed retention of THg (minus any subsequent volatilization) was 96.6% at Allequash, 60% at Sleepers, and 83% at Andrews. Icacos had a net export of THg, possibly due to historic gold mining or frequent disturbance from landslides. Quantification and interpretation of Hg dynamics was facilitated by the small watershed approach with emphasis on event sampling.     

Fine particulate matter emissions inventories: comparisons of emissions estimates with observations from recent field programs

Emissions inventories of fine particulate matter (PM2.5) were compared with estimates of emissions based on data emerging from U.S. Environment Protection Agency Particulate Matter Supersites and other field programs. Six source categories for PM2.5 emissions were reviewed: on-road mobile sources, nonroad mobile sources, cooking, biomass combustion, fugitive dust, and stationary sources. Ammonia emissions from all of the source categories were also examined. Regional emissions inventories of PM in the exhaust from on-road and nonroad sources were generally consistent with ambient observations, though uncertainties in some emission factors were twice as large as the emission factors. In contrast, emissions inventories of road dust were up to an order of magnitude larger than ambient observations, and estimated brake wear and tire dust emissions were half as large as ambient observations in urban areas. Although comprehensive nationwide emissions inventories of PM2.5 from cooking sources and biomass burning are not yet available, observational data in urban areas suggest that cooking sources account for approximately 5-20% of total primary emissions (excluding dust), and biomass burning sources are highly dependent on region. Finally, relatively few observational data were available to assess the accuracy of emission estimates for stationary sources. Overall, the uncertainties in primary emissions for PM2.s are substantial. Similar uncertainties exist for ammonia emissions. Because of these uncertainties, the design of PM2.5 control strategies should be based on inventories that have been refined by a combination of bottom-up and top-down methods.     

Synthetic fibers as an indicator of land application of sludge

Synthetic fabric fibers have been proposed as indicators of past spreading of wastewater sludge. Synthetic fiber detectability was examined in sludges (dewatered, pelletized, composted, alkaline-stabilized) and in soils from experimental columns and field sites applied with those sludge products. Fibers (isolated by water extraction and examined using polarized light microscopy) were detectable in sludge products and in soil columns over 5 years after application, retaining characteristics observed in the applied sludge. Concentrations mirrored (within a factor of 2) predictions based on soil dilution. Fibers were detectable in field site soils up to 15 years after application, again retaining the characteristics seen in sludge products. Concentrations correlated with residual sludge metal concentration gradients in a well-characterized field site. Fibers found along preferential flow paths and/or in horizons largely below the mixed layer suggest some potential for translocation. Synthetic fibers were shown to be rapid and semi-quantitative indicators of past sludge application.