Developing a risk assessment strategy for the Chesapeake Bay

Increased use of the world's natural resources, including water bodies such as the Chesapeake Bay, has resulted in additional burdens being placed on them. If continued, unrestricted use of such resources continues, degradation will occur to such an extent that some areas will be unsuitable for economic, social, and environmental uses. Regional risk assessment strategies must be developed so that actual or perceived risks can be evaluated and predicted on a regional scale. This article presents an initial strategy for the Chesapeake Bay that may be useful to scientists, managers, and elected officials responsible for other bodies of water as well. This article reviews risk assessment practices and proposes a strategy that utilizes appropriate endpoints to ascertain and predict risk.     

Invasion Pressure to a Ballast-flooded Estuary and an Assessment of Inoculant Survival

The relationships between invasion pressure, post-transport inoculant survival, and regional susceptibility to invasion are poorly understood. In marine ecosystems, the movement and release of ballast water from ocean-going ships provides a model system by which to examine the interplay among these factors. One of the largest estuaries in North America, the Chesapeake Bay, receives tremendous amounts of foreign ballast water annually and thus should be at high invasion risk. To date, however, few introductions in Chesapeake Bay have been attributed to ballast release. To understand better the dynamics of this invasion process, we (1) characterized and quantified the biota arriving to Chesapeake Bay in foreign ballast water, (2) compared temperatures and salinities of ballast water and harbor water in upper Chesapeake Bay, and (3) tested experimentally survival of organisms collected from ballast water in temperatures and salinities characteristic of the region. From 1993 to 1994, we sampled planktonic and benthic organisms from 60 foreign vessels arriving to Chesapeake Bay. Our data show that the estuary is being inoculated by a diverse assemblage of aquatic organisms from around the world. Furthermore, the short transit time (15d) for most vessels ensured that substantial numbers of larval and post-larval organisms were being deballasted alive. Most of the ballast water discharged into the upper Chesapeake Bay, however, was significantly higher in salinity (>20) than that of the receiving harbor. In laboratory tolerance experiments, ballast water organisms perished under such conditions. Thus, a mismatch in physical conditions between donor and receiver regions may explain the dearth of invasions in the upper Bay. It is likely that the lower Chesapeake Bay, which is more saline, remains at higher risk to ballast water invasion. Recognition of such intraregional differences should allow more focused predictions for monitoring and management.     

Long-Term Sickness Absence Due to Mental Disorders Is Associated with Individual Features and Psychosocial Work Conditions

Aims

Sickness absence is a socioeconomic global burden. In Brazil, mental disorders are the third leading cause of social security benefits payments. The aim of the present study was to compare factors associated with long-term sickness absence between workers who claimed social benefits due to mental disorders or by other causes. We investigated individual features and occupational characteristics. In addition, we evaluated psychosocial factors at work assessed by the Demand-Control-Support (DCS) and Effort-Reward Imbalance (ERI) models, and whether they were associated with long-term sickness absence due to mental disorders (LTSA-MD).

Methods

The present case-control study was conducted in São Paulo, Brazil. The sample (n = 385) included workers on sick leave for more than 15 days. Cases were the participants with disabling psychiatric illnesses, and controls were the ones with other disabling diseases. Interviews were conducted to assess individual features (sociodemographic data, health habits/lifestyle, health conditions) and occupational characteristics. The participants'' perception of exposure to dimensions of the DCS and ERI models was also recorded. Multiple logistic regressions were performed to evaluate the association between independent variables and LTSA-MD.

Results

All the regression analyses showed that LTSA-MD was associated with female sex, self-reported white skin color, higher education level, high tobacco consumption, high alcohol intake, two or more comorbidities, exposure to violence at work, high job strain and low social support at work, effort-reward imbalance and high overcommitment to work. LTSA-MD was associated with separate and combined DCS and ERI stress models.

Conclusions

Individual features and work conditions were associated with LTSA-MD. Combined analysis of stress models showed that psychosocial factors at work were significantly associated with LTSA-MD. Resourceful use of this information may contribute to the implementation of preventive actions and strategies to facilitate return to work targeting the populations most susceptible to mental disorders.     

Endospores of halophilic bacteria of the family Bacillaceae isolated from non-saline Japanese soil may be transported by Kosa event (Asian dust storm)

Background

Natural microbial communities are extremely complex and dynamic systems in terms of their population structure and functions. However, little is known about the in situ functions of the microbial communities.

Results

This study describes the application of proteomic approaches (metaproteomics) to observe expressed protein profiles of natural microbial communities (metaproteomes). The technique was validated using a constructed community and subsequently used to analyze Chesapeake Bay microbial community (0.2 to 3.0 μm) metaproteomes. Chesapeake Bay metaproteomes contained proteins from pI 4–8 with apparent molecular masses between 10–80 kDa. Replicated middle Bay metaproteomes shared ~92% of all detected spots, but only shared 30% and 70% of common protein spots with upper and lower Bay metaproteomes. MALDI-TOF analysis of highly expressed proteins produced no significant matches to known proteins. Three Chesapeake Bay proteins were tentatively identified by LC-MS/MS sequencing coupled with MS-BLAST searching. The proteins identified were of marine microbial origin and correlated with abundant Chesapeake Bay microbial lineages, Bacteroides and α-proteobacteria.

Conclusion

Our results represent the first metaproteomic study of aquatic microbial assemblages and demonstrate the potential of metaproteomic approaches to link metagenomic data, taxonomic diversity, functional diversity and biological processes in natural environments.     

Local and regional disturbances associated with the invasion of Chesapeake Bay marshes by the common reed <Emphasis Type="Italic">Phragmites australis</Emphasis>

The invasion of wetlands by Phragmites australis is a conservation concern across North America. We used the invasion of Chesapeake Bay wetlands by P. australis as a model system to examine the effects of regional and local stressors on plant invasions. We summarized digital maps of the distributions of P. australis and of potential stressors (especially human land use and shoreline armoring) at two spatial scales: for 72 subestuaries of the bay and their local watersheds and for thousands of 500 m shoreline segments. We developed statistical models that use the stressor variables to predict P. australis prevalence (% of shoreline occupied) in subestuaries and its presence or absence in 500 m segments of shoreline. The prevalence of agriculture was the strongest and most consistent predictor of P. australis presence and abundance in Chesapeake Bay, because P. australis can exploit the resulting elevated nutrient levels to enhance its establishment, growth, and seed production. Phragmites australis was also positively associated with riprapped shoreline, probably because it creates disturbances that provide colonization opportunities. The P. australis invasion was less severe in areas with greater forested land cover and natural shorelines. Surprisingly, invasion was low in highly developed watersheds and highest along shorelines with intermediate levels of residential land use, possibly indicating that highly disturbed systems are uninhabitable even to invasive species. Management strategies that reduce nutrient pollution, preserve natural shorelines, and limit nearshore disturbance of soils and vegetation may enhance the resilience of shorelines to invasion.     

Examining the social landscapes of alternative reproductive strategies

Social environments are inherently dynamic, often changing depending on the frequency and outcomes of conspecific interactions – they can be simultaneously the targets and agents of selection. Understanding how organisms settle in heterogeneous social environments and the effects this has on reproductive success is vital to our understanding of the selective forces at work in wild populations. From an intensive behavioural and ecological study of territoriality in the polymorphic white‐throated sparrow (Zonotrichia albicollis), we demonstrate that males of the two morphs inhabit social niches that correspond to their respective alternative reproductive strategies. By integrating molecular ecology and Geographic Information Systems, we generated continuous, socio‐spatial models of local conspecific density and cuckoldry risk. Our results suggest that the morphs segregate their territories based on socio‐spatial variables, creating a heterogeneous social landscape that matches each behavioural phenotype with a favourable social environment. Specifically, the monogamous tan males tended to settle in low‐density areas that were also low for cuckoldry risk, while the opposite was true for the promiscuous white males. This pattern of socio‐spatial heterogeneity, combined with the social niche partitioning we observed, might act as a social niche polymorphism, and play an important role in maintenance of the alternative reproductive strategies of the white‐throated sparrow. Socio‐spatial factors, similar to those observed in the white‐throated sparrow, may play important roles in the evolution of mating systems in other species, even those with more continuous or cryptic variation.     

Evidence for varying social strategies across the day in chacma baboons

Strong social bonds can make an important contribution to individual fitness, but we still have only a limited understanding of the temporal period relevant to the adjustment of social relationships. While there is growing recognition of the importance of strong bonds that persist for years, social relationships can also vary over weeks and months, suggesting that social strategies may be optimized over shorter timescales. Using biological market theory as a framework, we explore whether temporal variation in the benefits of social relationships might be sufficient to generate daily adjustments of social strategies in wild baboons. Data on grooming, one measure of social relationships, were collected from 60 chacma baboons (Papio ursinus) across two troops over a six month period. Our analyses suggest that social strategies can show diurnal variation, with subordinates preferentially grooming more dominant individuals earlier in the day compared with later in the day. These findings indicate that group-living animals may optimize certain elements of their social strategies over relatively short time periods.     

Taste the Traditions: Crabs, Crab Cakes, and the Chesapeake Bay Blue Crab Fishery

For centuries, people in the Chesapeake Bay watershed have harvested and consumed blue crabs (Callinectes sapidus). Historically, the production of the crabs was intimately connected to the work and knowledge of commercial watermen. In recent years, declining crab populations have resulted in an increased local use of pasteurized crab meat imported from Asia and South America. Also emerging is an ecological discourse that emphasizes pollution reduction to save crabs to eat. In this article, I analyze these production and consumption changes for Chesapeake Bay blue crabs within a broad-ranging framework of cultural models and environmental anthropology. Explicit textual information increasingly suggests that the cultural model of Chesapeake blue crabs as food is one of crab cakes made (with imported crab meat) in the "local tradition" and, to a lesser degree so far, is an emerging discourse presenting blue crabs as a culinary poster child for antipollution campaigns.     

Dip listening and the cocktail party problem in grey treefrogs: Signal recognition in temporally fluctuating noise

Dip listening refers to our ability to catch brief "acoustic glimpses" of speech and other sounds when fluctuating background noise levels momentarily decrease. Exploiting dips in natural fluctuations of noise contributes to our ability to overcome the "cocktail party problem" of understanding speech in multi-talker social environments. We presently know little about how nonhuman animals solve analogous communication problems. Here, we asked whether female grey treefrogs (Hyla chrysoscelis) might benefit from dip listening in selecting a mate in the noisy social setting of a breeding chorus. Consistent with a dip listening hypothesis, subjects recognized conspecific calls at lower thresholds when the dips in a chorus-like noise masker were long enough to allow glimpses of nine or more consecutive pulses. No benefits of dip listening were observed when dips were shorter and included five or fewer pulses. Recognition thresholds were higher when the noise fluctuated at a rate similar to the pulse rate of the call. In a second experiment, advertisement calls comprising six to nine pulses were necessary to elicit responses under quiet conditions. Together, these results suggest that in frogs, the benefits of dip listening are constrained by neural mechanisms underlying temporal pattern recognition. These constraints have important implications for the evolution of male signalling strategies in noisy social environments.     

Evaluating the Risk of Establishing a Self-Sustaining Population of Non-Native Oysters Through Large-Scale Aquaculture in Chesapeake Bay

A multistep invasive species methodology was used to evaluate the probability that the deployment of sterile non-native oysters (Crassostrea ariakensis, called Asian oyster) in field-based aquaculture could give rise to a reproductive population in Chesapeake Bay. Several pathways that could potentially lead to the unintentional release of reproductive C. ariakensis from aquaculture were identified. For the four quantifiable pathways, a probability was estimated for each step based on knowledge of ecological rates. A conservative estimate for the number of reproductive C. ariakensis that could arise over one spawning season at a hypothetical aquaculture site was estimated. A statistical expansion of this probability estimated that it is highly likely that the cultivation of putatively sterile C. ariakensis would initiate a reproductive population in Chesapeake Bay over a 10-year time span. The potential benefits of restoration actions involving non-native species in estuarine ecosystems must be weighed against potential ecological risks. A probabilistic approach can provide a useful method for summarizing the risk of an unintended introduction that may occur despite a reasonable and presumably “safe” approach for realizing benefits of a non-native species in aquaculture. The results presented here have important implications for future proposals involving the commercial use of non-native species in natural ecosystems.     

Anaerobic Ammonium Oxidation (Anammox) in Chesapeake Bay Sediments

Anaerobic ammonium oxidation (anammox) has recently been recognized as a pathway for the removal of fixed N from aquatic ecosystems. However, the quantitative significance of anammox in estuarine sediments is variable, and measurements have been limited to a few estuaries. We measured anammox and conventional denitrification activities in sediments along salinity gradients in the Chesapeake Bay and two of its sub-estuaries, the Choptank River and Patuxent River. Homogenized sediments were incubated with ^14/15N amendments of , , and to determine relative activities of anammox and denitrification. The percent of N₂ production due to anammox (ra%) ranged from 0 to 22% in the Chesapeake system, with the highest ra% in the freshwater portion of the main stem of upper Chesapeake Bay, where water column concentrations are consistently high. Intermediate levels of relative anammox (10%) were detected at locations corresponding to tidal freshwater and mesohaline locations in the Choptank River, whereas anammox was not detected in the tidal freshwater location in the Patuxent River. Anammox activity was also not detected in the seaward end of Chesapeake Bay, where water column concentrations are consistently low. The ra% did not correlate with accumulation rate in anoxic sediment incubations, but ra% was related to water column concentrations and salinity. Anammox bacterial communities were also examined by amplifying DNA extracted from the upper Chesapeake Bay sediment with polymerase chain reaction (PCR) primers that are specific for 16S rRNA genes of anammox organisms. A total of 35 anammox-like sequences were detected, and phylogenetic analysis grouped the sequences in two distinct clusters belonging to the Candidatus “Scalindua” genus.     

Powhatan's Werowocomoco: Constructing Place, Polity, and Personhood in the Chesapeake, C.E. 1200--C.E. 1609

Colonial encounters within the Powhatan village of Werowocomoco in Tidewater Virginia have captured the public's imagination through romantic literature and popular films. Shifting the focus of inquiry away from English colonial narratives and toward a history of landscape provides an alternative understanding of Werowocomoco as a Native place. Archaeological investigation has identified evidence of earthworks and related social practices that altered Werowocomoco's built environment and subjective experiences of its spaces in ways that colonial chroniclers failed to appreciate. A landscape history combining built environments, cognitive maps, and spatial practices across the historic—precontact divide indicates that the settlement became a ritualized location for the production of political status and social personhood well before English colonization in the Chesapeake. Spatial practices rooted in Algonquian cosmology and centered on Werowocomoco shaped the origins of the Powhatan chiefdom and early colonial history through which Powhatans sought to incorporate Jamestown colonists into their world. A biography of Werowocomoco as a Native place illustrates how a deep historical anthropology may challenge notions of a "prehistoric" past comprised of homogenized societies lacking history.     

A review of phytoplankton composition within Chesapeake Bay and its tidal estuaries

Based on a continuous 20-year data base of monthly samplingin Chesapeake Bay and tidal regions of its major tributaries,1454 phytoplankton taxa have been identified in these waters.They represent a diverse assemblage of species with a dominantdiatom flora throughout the year, in addition to large seasonalrepresentation by chlorophytes, cyanobacteria, cryptophytesand dinoflagellates. Included among this flora were 34 potentialharmful or toxin producing species. The phytoplankton compositionsassociated with the seasonal successional patterns are discussed,in addition to characterizing the dominant floral relationships,with comparison to early composition records within the Bay.Several of the present day most common taxa were similar tothose reported in sediment cores from the Bay dating to periodsprior to European settlement. Comparison with collections made8 decades ago (1916–1922) within Chesapeake Bay indicatedseveral of the same dominant flora remain dominant today; however,their cell concentrations are now significantly greater alongwith an increased diversity of species compared with these earlierstudies.     

Learning, climate and the evolution of cultural capacity

Patterns of environmental variation influence the utility, and thus evolution, of different learning strategies. I use stochastic, individual-based evolutionary models to assess the relative advantages of 15 different learning strategies (genetic determination, individual learning, vertical social learning, horizontal/oblique social learning, and contingent combinations of these) when competing in variable environments described by 1/f noise. When environmental variation has little effect on fitness, then genetic determinism persists. When environmental variation is large and equal over all time-scales ("white noise") then individual learning is adaptive. Social learning is advantageous in "red noise" environments when variation over long time-scales is large. Climatic variability increases with time-scale, so that short-lived organisms should be able to rely largely on genetic determination. Thermal climates usually are insufficiently red for social learning to be advantageous for species whose fitness is very determined by temperature. In contrast, population trajectories of many species, especially large mammals and aquatic carnivores, are sufficiently red to promote social learning in their predators. The ocean environment is generally redder than that on land. Thus, while individual learning should be adaptive for many longer-lived organisms, social learning will often be found in those dependent on the populations of other species, especially if they are marine. This provides a potential explanation for the evolution of a prevalence of social learning, and culture, in humans and cetaceans.     

The 24-hour society between myth and reality

The 24-hour society appears to be an ineluctable process towards a social organisation where time constraints are no more "restricting" the human life. But, what kind of 24-hour society do we need? At what costs? Are they acceptable/sustainable? Shift work, night work, irregular and flexible working hours, together with new technologies, are the milestone of this epochal passage, of which shift workers are builders and victims at the same time. The borders between working and social times are no more fixed and rigidly determined: not only the link between work place and working hours is broken, but also the value of working time changes according to the different economic/productive/social effects it can make. What are the advantages and disadvantages for the individual, the companies, and the society? What is the cost/benefit ratio in terms of physical health; psychological well-being, family and social life? The research on irregular working hours and health shows us what can be the negative consequences of non-human-centered working times organisations. Coping properly with this process means avoiding a passive acceptance of it with consequent maladjustments at both individual and social level, but adopting effective preventive and compensative strategies aimed at building a more sustainable society, at acceptable costs and with the highest possible benefits.     

Relationships between bed age,bed size,and genetic structure in Chesapeake Bay (Virginia,USA) eelgrass (<Emphasis Type="Italic">Zostera marina</Emphasis> L.)

Genetic structure and diversity can reveal the demographic and selective forces to which populations have been exposed, elucidate genetic connections among populations, and inform conservation strategies. Beds of the clonal marine angiosperm Zostera marinaL. (eelgrass) in Chesapeake Bay (Virginia, USA) display significant morphological and genetic variation; abundance has fluctuated widely in recent decades, and eelgrass conservation is a major concern, raising questions about how genetic diversity is distributed and structured within this metapopulation. This study examined the influence of bed age (<65years versus<6years) and size (>100ha versus<10ha) on morphological and genetic (allozyme) structure and diversity within Chesapeake Bay eelgrass beds. Although both morphology and genetic diversity varied significantly among individual beds (F _ST=0.198), neither varied consistently with bed age or size. The Chesapeake eelgrass beds studied were significantly inbred (mean F _IS=0.680 over all beds), with inbreeding in old, small beds significantly lower than in other bed types. Genetic and geographic distances within and among beds were uncorrelated, providing no clear evidence of isolation by distance at the scale of 10's of km. These results suggest that local environmental conditions have a greater influence on plant morphology than do bed age or size. They support the hypotheses that eelgrass beds are established by multiple founder genotypes but experience little gene flow thereafter, and that beds are maintained with little loss of genetic diversity for up to 65 years. Since phenotypic and genotypic variation is partitioned among beds of multiple ages and sizes, eelgrass conservation efforts should maximize preservation of diversity by minimizing losses of all beds.     

Kinship,parental manipulation and evolutionary origins of eusociality

One of the hallmarks of eusociality is that workers forego their own reproduction to assist their mother in raising siblings. This seemingly altruistic behaviour may benefit workers if gains in indirect fitness from rearing siblings outweigh the loss of direct fitness. If worker presence is advantageous to mothers, however, eusociality may evolve without net benefits to workers. Indirect fitness benefits are often cited as evidence for the importance of inclusive fitness in eusociality, but have rarely been measured in natural populations. We compared inclusive fitness of alternative social strategies in the tropical sweat bee, Megalopta genalis, for which eusociality is optional. Our results show that workers have significantly lower inclusive fitness than females that found their own nests. In mathematical simulations based on M. genalis field data, eusociality cannot evolve with reduced intra-nest relatedness. The simulated distribution of alternative social strategies matched observed distributions of M. genalis social strategies when helping behaviour was simulated as the result of maternal manipulation, but not as worker altruism. Thus, eusociality in M. genalis is best explained through kin selection, but the underlying mechanism is likely maternal manipulation.     

Reducing CO<Subscript>2</Subscript> Emissions from Domestic Travel: Exploring the Social and Health Impacts

The importance and meaning of social and recreational travel for a diverse group of Auckland residents is explored in this article. Study participants identified a range of social and health benefits, including maintaining social connections with family and friends, opportunities to participate in physical activity, and reducing stress. However, many of these trips are by car. New Zealand has one of the highest rates of private car ownership internationally, low-density urban development, and a poor public transport infrastructure. Social and recreational trips make up a sizeable proportion of domestic travel and are contributing to New Zealand’s increasing rate of CO₂ emissions. There is an obvious need to address the negative ecological impacts of human activity. Our findings suggest that alongside strategies to reduce CO₂ emissions, it also is important to introduce measures to maintain the benefits from social and recreational travel. Suggestions are made for further areas of research.     

Spatial and temporal variability of juvenile spotted seatrout Cynoscion nebulosus growth in Chesapeake Bay

Juvenile spotted seatrout Cynoscion nebulosus growth in Chesapeake Bay was compared to growth from southerly estuaries to examine the potential for countergradient growth variation, and finer scale growth variation within Chesapeake Bay was investigated further. Because spawning and growing seasons in Chesapeake Bay are much shorter than in southern populations, and the bay population is genetically distinct, it was expected that C. nebulosus in Chesapeake Bay may exhibit faster juvenile growth than their southern counterparts. Within the bay, spatial and temporal growth patterns were examined using a repeated measures linear mixed-effects model on individual retrospective growth histories. Juvenile C. nebulosus were collected from seagrass beds throughout Chesapeake Bay in 1997–1999 and 2002; sagittae were removed for daily growth analysis. The calculated growth rate of 1·44 mm standard length day⁻¹ for Chesapeake Bay fish is two to three times that reported for Florida C. nebulosus . Within the bay from 1997 to 1999 (average rainfall years), growth patterns were similar with the fastest growing fish collected from seagrass beds in the central bay, followed by the eastern shore fish with intermediate growth and western shore fish that exhibited slowest growth. These results were reversed (western shore fish growth > eastern shore > central bay) in 2002 (a drought year) even though temperatures across all years were similar throughout the bay, indicating that growth may be influenced by freshwater inflows.     

Structural and Psycho-Social Limits to Climate Change Adaptation in the Great Barrier Reef Region

Adaptation, as a strategy to respond to climate change, has limits: there are conditions under which adaptation strategies fail to alleviate impacts from climate change. Research has primarily focused on identifying absolute bio-physical limits. This paper contributes empirical insight to an emerging literature on the social limits to adaptation. Such limits arise from the ways in which societies perceive, experience and respond to climate change. Using qualitative data from multi-stakeholder workshops and key-informant interviews with representatives of the fisheries and tourism sectors of the Great Barrier Reef region, we identify psycho-social and structural limits associated with key adaptation strategies, and examine how these are perceived as more or less absolute across levels of organisation. We find that actors experience social limits to adaptation when: i) the effort of pursuing a strategy exceeds the benefits of desired adaptation outcomes; ii) the particular strategy does not address the actual source of vulnerability, and; iii) the benefits derived from adaptation are undermined by external factors. We also find that social limits are not necessarily more absolute at higher levels of organisation: respondents perceived considerable opportunities to address some psycho-social limits at the national-international interface, while they considered some social limits at the local and regional levels to be effectively absolute.