Restricted movements and mangrove dependency of the nervous shark Carcharhinus cautus in nearshore coastal waters.

This study used a network of acoustic receivers deployed around a no-take zone in Mangrove Bay, within the Ningaloo Reef Marine Park in Western Australia, to study residency and habitat preference of a small coastal shark, the nervous shark Carcharhinus cautus. Twelve C. cautus were tagged with acoustic tags and monitored for up to 579 days. Based on individuals detected within the receiver array for at least 2 months, C. cautus had small core (50% kernel utilization distribution, KUD) and home ranges (95% KUD) of 0.66 and 3.64 km2, respectively, and showed a strong habitat preference for mangroves, which are only found in the no-take zone. This resulted in C. cautus spending most of their detected time within the no-take zone boundaries (mean = 81.5%), showing that such a protected area could be beneficial to protect this species from extensive fishing pressure and local depletion, where required. Not all C. cautus remained within the acoustic array, however, suggesting that individual variations occur and that not all individuals would benefit from such protection. This study provides important information about the habitat, residency and movements of C. cautus that can be used for management and conservation. The strong affinity and residency of C. cautus within a mangrove-fringing coastline, emphasizes the importance of mangrove habitat to the species and suggests that such preferences can be used to design appropriate no-take zones for this species or others with similar habitat preferences.

Critical research needs for managing coral reef marine protected areas: perspectives of academics and managers.

Marine protected areas (MPAs) are a primary policy instrument for managing and protecting coral reefs. Successful MPAs ultimately depend on knowledge-based decision making, where scientific research is integrated into management actions. Fourteen coral reef MPA managers and sixteen academics from eleven research, state and federal government institutions each outlined at least five pertinent research needs for improving the management of MPAs situated in Australian coral reefs. From this list of 173 key questions, we asked members of each group to rank questions in order of urgency, redundancy and importance, which allowed us to explore the extent of perceptional mismatch and overlap among the two groups. Our results suggest the mismatch among MPA managers and academics is small, with no significant difference among the groups in terms of their respective research interests, or the type of questions they pose. However, managers prioritised spatial management and monitoring as research themes, whilst academics identified climate change, resilience, spatial management, fishing and connectivity as the most important topics. Ranking of the posed questions by the two groups was also similar, although managers were less confident about the achievability of the posed research questions and whether questions represented a knowledge gap. We conclude that improved collaboration and knowledge transfer among management and academic groups can be used to achieve similar objectives and enhance the knowledge-based management of MPAs.

Decadal trends in marine reserves reveal differential rates of change in direct and indirect effects.

Decadal-scale observations of marine reserves suggest that indirect effects on taxa that occur through cascading trophic interactions take longer to develop than direct effects on target species. Combining and analyzing a unique set of long-term time series of ecologic data in and out of fisheries closures from disparate regions, we found that the time to initial detection of direct effects on target species (±SE) was 5.13 ± 1.9 years, whereas initial detection of indirect effects on other taxa, which were often trait mediated, took significantly longer (13.1 ± 2.0 years). Most target species showed initial direct effects, but their trajectories over time were highly variable. Many target species continued to increase, some leveled off, and others decreased. Decreases were due to natural fluctuations, fishing impacts from outside reserves, or indirect effects from target species at higher trophic levels. The average duration of stable periods for direct effects was 6.2 ± 1.2 years, even in studies of more than 15 years. For indirect effects, stable periods averaged 9.1 ± 1.6 years, although this was not significantly different from direct effects. Populations of directly targeted species were more stable in reserves than in fished areas, suggesting increased ecologic resilience. This is an important benefit of marine reserves with respect to their function as a tool for conservation and restoration.

Nitrate distributions and source identification in the Abbotsford-Sumas Aquifer, northwestern Washington State.

The Abbotsford-Sumas Aquifer is a shallow, predominantly unconfined aquifer that spans regions in southwestern British Columbia, Canada and northwestern Washington, USA. The aquifer is prone to nitrate contamination because of extensive regional agricultural practices. A 22-month ground water nitrate assessment was performed in a 10-km2 study area adjacent to the international boundary in northwestern Washington to examine nitrate concentrations and nitrogen isotope ratios to characterize local source contributions from up-gradient sources in Canada. Nitrate concentrations in excess of 10 mg nitrate as nitrogen per liter (mg N L(-1)) were observed in ground water from most of the 26 domestic wells sampled in the study area, and in a creek that dissects the study area. The nitrate distribution was characteristic of nonpoint agricultural sources and consistent with the historical documentation of agriculturally related nitrate contamination in many parts of the aquifer. Hydrogeologic information, nitrogen isotope values, and statistical analyses indicated a nitrate concentration stratification in the study area. The highest concentrations (> 20 mg N L(-1)) occurred in shallow regions of the aquifer and were linked to local agricultural practices in northwestern Washington. Nitrate concentrations in excess of 10 mg N L(-1) deeper in the aquifer (> 10 m) were related to agricultural sources in Canada. The identification of two possible sources of ground water nitrate in northwestern Washington adds to the difficulty in assessing and implementing local nutrient management plans for protecting drinking water in the region.

Sexual conflict and polyspermy under sperm-limited conditions: in situ evidence from field simulations with the free-spawning marine echinoid Evechinus chloroticus.

For free-spawning organisms that release gametes into the sea, sperm limitation (too few sperm to fertilize all eggs) is a major factor limiting reproductive success. Given such circumstances, the presence of several mechanisms to prevent polyspermy (too many sperm) may seem paradoxical; however, a growing body of data suggests that natural fertilization levels, though variable, can routinely be high. Under such conditions, polyspermy is much more likely. The tension between sperm limitation and polyspermy represents sexual conflict because males, in competing to fertilize as many eggs as possible, can impose lethal costs on eggs if multiple sperm gain entry. Here we present data for a marine invertebrate indicating high levels of polyspermy under sperm-limited conditions. When the sea urchin Evechinus chloroticus was induced to spawn in situ, mean rates of polyspermy were [Formula: see text], and polyspermy was recorded at rates as high as 62.7%. Polyspermy was nearly always present, even when fertilization rates were <50%, confirming predictions that it should be present under sperm-limited conditions. Both sperm limitation and polyspermy imposed substantial reproductive costs, and we conclude that both sexual conflict related to polyspermy and sperm limitation have been simultaneous strong selective forces shaping the evolution of reproductive traits in the sea.

N2,N2,7-trimethylguanine, a new trimethylated guanine natural product from the New Zealand ascidian, Lissoclinum notti.

From the New Zealand ascidian, Lissoclinum notti a new natural product, N2,N2,7-trimethylguanine (1) has been isolated. The structure of 1 was elucidated by analysis of spectroscopic data.

Use of biodegradable dissolved organic carbon to assess treatment process performance in relation to solids retention time.

A biodegradable dissolved organic carbon (BDOC) method has been developed and used to analyze secondary- and advanced-treated wastewater effluents and to investigate correlations between residual organic content and the solids retention time (SRT). Conventional biochemical oxygen demand (BOD) bottles and a 28-day incubation period were used. Secondary wastewater effluents from Hawaii were found to contain between 9.0 and 14.0 mg/L of dissolved organic carbon (DOC), of which 23 to 35% was biodegradable in the 28-day BDOC test (from a survey of nine treatment plants). Bench-scale, continuous-flow activated-sludge biological reactors treating synthetic wastewater were operated at SRTs between 2 and 15 days, and effluent BDOCs were determined. A good BDOC prediction equation was developed that incorporates the initial DOC, the DOC remaining after 5 days, and the SRT of the system from which the sample originated. This equation can be used to determine the BDOC value using data that can be obtained during a conventional 5-day BOD test. The determined equation was found to be appropriate for some of the full-scale wastewater effluent survey data.

Computer testing of memory across the adult life span.

This study was designed to investigate whether differential experience with and reactions to computers among adults of different ages impact on adult age differences in computer memory testing. Participants were 141 community-dwelling adults, aged 18 to 87. Computer experience, computer anxiety, computer attitudes, and computer self-efficacy were measured in addition to several demographic items. Participants also completed a working-memory test on a desk top computer. Age was positively correlated with computer anxiety, but was not correlated with computer attitudes. In addition, older adults had less computer experience and lower computer self-efficacy. Computer experience, anxiety, and self-efficacy significantly mediated the relationship between age and computer-tested working memory performance. The results lend support to a model of cognitive aging that emphasizes the role of ability-extraneous factors in accounting for some of the observed age-related differences in computer-tested memory.

Comparative evaluation of chlamydiazyme, PACE 2, and AMP-CT assays for detection of Chlamydia trachomatis in endocervical specimens.

We conducted a comparative evaluation of the Chlamydiazyme (Abbott Laboratories), PACE 2 (Gen-Probe), and AMP-CT (Gen-Probe) assays for the detection of Chlamydia trachomatis in endocervical samples. Specimens from 787 females were included in the study. The sensitivities of the PACE 2 and Chlamydiazyme assays in comparison to the results of the AMP-CT assay were 79.3 and 63.4%, respectively. The specificities of the Chlamydiazyme and PACE 2 assays were 100%. All of the positive specimens detected in this study were positive by the AMP-CT assay. On the basis of the final results of the comparison, the prevalence of C. trachomatis in the population was 10.4%. Retesting of specimens whose results were in the intermediate zone by the PACE 2 assay by a probe competition assay identified some additional true-positive specimens. Amplification assay testing of such specimens did not significantly increase the yield. The majority of specimens which tested positive by the AMP-CT assay only were not in the intermediate zone by the PACE 2 assay. We were unable to identify demographic or clinical factors which could predict those individuals who tested positive by amplified tests but not by nonamplified tests. The Gen-Probe PACE 2 assay proved to be superior to the Chlamydiazyme assay for the screening and diagnosis of C. trachomatis infections in female endocervical specimens.

A comparison of the factor structure of processing speed for younger and older adults: testing the assumption of measurement equivalence across age groups.

The purpose of this study was to investigate measurement equivalence of processing speed measures for different age groups. A structural equation modeling approach was used to investigate a measurement model and the factorial invariance between younger and older adults on speed measures. The analyses concurrently examined whether speed-related abilities dedifferentiate with increasing age. One hundred and forty-four younger and 105 older adults completed 9 measures designed to assess motor speed, alphanumeric speed, and geometric speed. Results indicated that although the number of factors and the factor loadings were invariant across age groups, the interfactor correlations, the variance-covariance matrices, and the unique variances differed across groups. Furthermore, a second-order speed factor seemed to explain much of the variance in the 3 first-order factors, although this higher order factor accounted for slightly more variance among the older group than among the younger group. The results suggest that there is sufficient evidence of measurement equivalence on the current speed measures across the 2 adult age groups and, in addition, provide evidence of dedifferentiation.

Conflicting Morphological and Reproductive Species Boundaries in the Coral Genus Platygyra.

In mass-spawning corals, potential exists for gametes of a number of species to mix in the water column. The existence of morphologically distinct sympatric coral populations despite such an event implies the presence of isolating mechanisms to prevent hybridization and maintain species boundaries. Over 380 fertilization trials were conducted to determine the extent of reproductive isolation among the seven morphologically defined species (morphospecies) of the scleractinian coral genus Platygyra, on the Great Barrier Reef. Results from these experiments demonstrate that fertilization between-morphospecies can occur at rates equivalent to within-morphospecies fertilizations, indicating that no gametic-level barriers to fertilization exist among these morphological species. Observations of spawning times both in the field and in the laboratory have shown that all seven morphospecies spawn on the same night and that there is considerable overlap in the hour of spawning among them. These data indicate that few, if any, temporal barriers to fertilization exist among morphospecies of Platygyra on the Great Barrier Reef. In addition, larvae resulting from between-morphospecies crosses are capable of settlement and subsequent growth equivalent to that of within-morphospecies larvae. Our results reveal a discontinuity between reproductive and morphological species boundaries within the scleractinian genus Platygyra and challenge species definitions within the Scleractinia. It is not yet clear what mechanisms might maintain morphological boundaries in Platygyra in the face of the clear potential for gamete mixing. The disjunct distributions of certain morphospecies along latitudinal and habitat boundaries, and the small levels of variation in reproduction may be two such mechanisms.

Potential public health risks related to mercury/amalgam discharge from dental offices.

Mercury is a toxic and bioaccumulative metal. It exists in elemental, inorganic and organic forms. The use of mercury by the dental profession represents approximately 6 percent of the total annual domestic consumption and is estimated to contribute significantly to the discharge of mercury (14 percent in one study) to waste-water streams. Publicly owned treatment works (POTW) must obtain and comply with a National Pollutant Discharge Elimination System waste-water discharge permit. When minimal mercury discharge limits into surface waters are exceeded, an upstream search for contributors of mercury to the waste stream may result. Given the present sociopolitical environment, mercury discharge from dental offices will increasingly receive scrutiny. Strategies to minimize discharge of mercury/amalgam waste include engineering controls such as changes in the discharge process, changes in the composition of commercial products, and changes in control equipment. Governmental strategies include an outright ban, the setting of discharge standards, and educational efforts. Study of these strategies with evaluation of effectiveness is needed.

Synchronous multispecific spawning on coral reefs: potential for hybridization and roles of gamete recognition.

Problems of gamete recognition in corals and other mass-spawning invertebrates are potentially great. In 'mass spawnings', closely-related species or genera commonly spawn at the same time, or within 1 or 2 h of each other, increasing the potential for hybridization. Among mass-spawning corals, most of the species involved are hermaphrodites that package the gametes in buoyant bundles that float to the sea surface before breaking up. Local hydrodynamic features frequently act to aggregate gametes from many different species into slicks where both eggs and sperm can be viable for extended periods. Other mass-spawning invertebrate taxa, such as molluscs, polychaetes and various echinoderms, do not have buoyant gametes but also spawn with a high level of synchrony. Gametes of organisms participating in these spawning events must be able to successfully recognize conspecifics. If they cannot do this, either through sperm chemotaxis or by mechanisms at the level of sperm binding and penetration, there may be high levels of gamete wastage through hybridization. Alternatively, viable hybrids may be formed, a factor that could have contributed to the evolutionary history of mass-spawning taxa, as well as to the taxonomic difficulties that have plagued the taxonomy of groups such as reef-building corals. Within some mass-spawning taxa, pre-zygotic barriers to fertilization suggest relatively recent molecular evolution at gamete recognition loci.

Analysis of adult age differences on the Raven's Advanced Progressive Matrices Test.

The purpose of this project was to examine the nature of performance, and specifically, age-related performance, on the Raven's Advanced Progressive Matrices (APM) Test (Raven, Court, & Raven, 1983). In the 1st of 2 studies, 2 tests presumed to measure each of 4 hypothesized components of the APM and 3 tests presumed to measure processing speed were presented to 165 young adults. On the basis of correlational and confirmatory analyses, 1 of the components was not included in Study 2. The 2nd study was designed to examine the influence of the 3 remaining components, processing speed, and working memory on the individual and age-related differences on the APM. Participants included 183 adults between the ages of 21 and 83. The results suggest that although all 3 components are important to performance on the APM, rule application tasks seem to hold the most promise in accounting for age-related variance on the APM.

A Portable, Discrete-Sampling Submersible Plankton Pump and Its Use in Sampling Starfish Eggs.

The apparatus was designed to enable divers to obtain discrete replicate samples from known volumes of water. Relatively large volumes of water can be filtered without the need to maintain contact with or return to the surface. These attributes confer a high degree of flexibility in subsurface sampling situations. Although we used the equipment to sample the eggs of invertebrates, it could equally easily be used to sample other small, patchily distributed plankton.

Temperature and the Larval Ecology of the Crown-of-Thorns Starfish, Acanthaster planci.

The recently reported dramatic population increases (outbreaks) of the coral-eating crown-of-thorns starfish, Acanthaster planci, which have damaged many reefs in the Indo-Pacific, are ending (1), but questions remain about the factors that affect Acanthaster distribution and densities. For example, the narrow temperature tolerance (26° or 27° to 30° or 31°C) reported for Acanthaster's larval development (2) is problematic because Acanthaster occurs where temperatures do not rise into this range (3, 4). We have further examined some temperature relationships in Acanthaster's early development. Cleavage proceeded normally over a range of about 10°C but specific limiting temperatures depended upon the geographic source of the parents or their recent history of temperature exposure. Hatched, swimming gastrulae continued normal development to bipinnaria throughout a temperature range of 13°C. These results indicate that the narrow developmental temperature tolerances reported earlier for Acanthaster do not apply to all early developmental stages, and they add to the list of larval adaptations that can facilitate dispersal of Acanthaster larvae and propagation of outbreaks.

Sperm Diffusion Models and In Situ Confirmation of Long-Distance Fertilization in the Free-Spawning Asteroid Acanthaster planci.

This study was undertaken to compare fertilization rates of the sea star Acanthaster planci that were predicted using sperm diffusion models with those that were determined under natural conditions in the field. During experimentally induced spawnings, measured fertilization rates for broadcast eggs were high. More than 70% of the eggs were fertilized at distances as great as 8 m downstream from a single spawning male starfish, and more than 20% were fertilized at separations of more than 60 m. Fertilization was still measurable, at 5.8%, 100 m downstream. Lateral diffusion of sperm away from the axis of flow produced fertilization rates of 13.8% at 8 m normal to the flow and 32 m downstream. The large volumes of sperm released by male A. planci are the primary cause of high rates of fertilization for eggs derived from widely spaced individuals. Models of sperm diffusion using high sperm release rates such as those found in this starfish accurately confirmed the fertilization rates measured in situ for two populations of A. planci with widely differing rates of sperm release. We observed some changes in starfish density and degree of aggregation in the study population for spawning periods during two spawning seasons, though these were not striking. High levels of aggregation may not be necessary for fertilization success in this starfish, due to the potential for long-distance fertilization and the probability that, for any spawning starfish, the total number of zygotes formed will be greater at some distance from the point of spawning. Although fertilization rates in areas distant from the sperm source were relatively low, the total area for potential gamete encounters is much greater and may make a large contribution to net fertilization. We predict that other behaviors, such as migration to shallow water, commonly associated with spawning in A. planci and other marine invertebrates will have measurable impacts on fertilization success. The potential for high levels of fertilization in A. planci was realized during natural spawnings. Fertilization rates as high as 99% were recorded when levels of spawning synchrony were high.

Increasing nurses' use of feedback to promote infection-control practices in a head-injury treatment center.

This study established regular implementation of a simple feedback procedure by supervisory nurses with their assistants at a head-injury treatment center. Five nurses were trained to distribute brief written comments to their assistants about infection-control practices, including using gloves to avoid contact with body fluids. Following low rates of written feedback, nurses met with the trainer weekly to set goals for using the system, to review feedback rates, and to examine contingent letters of appreciation. Written feedback increased from 0.09 to 0.58 per day. When outcome data on glove use were subsequently added to the feedback provided to nurses, nurses' feedback on glove use increased and overall glove use by assistants increased by 36.7% for 66.7% of assistants who responded to feedback. Assistants rated feedback as highly accurate and indicated some interest in receiving future feedback. However, nurses and assistants expressed a preference for oral over written feedback.