Assessment of contaminant impacts in a semi-enclosed estuary (Amvrakikos Gulf, NW Greece): Bioenergetics and biochemical biomarkers in mussels

A combination of bioenergetics and biochemical biomarkers in mussels was applied to assess possible pollution impacts in a protected semi-enclosed estuary (Amvrakikos Gulf, NW Greece) that receives pesticide discharges through riverine transport. Scope for growth, a physiological condition index representing the energy budget of the organism, was applied to detect general stress effects on the health status of mussels. The low energy budgets of mussels revealed stress conditions and provided early warning signals of possible consequences at higher levels of biological organization. Biochemical markers of exposure confirmed a risk of pesticide contamination. Decreased acetylcholinesterase activities indicated exposure to organophosphate and carbamate pesticides. Responses of the antioxidant enzyme glutathione peroxidase suggested the presence of contaminants capable of reactive oxygen species production that could be related to organochlorine pesticide contamination in the area. On the other hand, metallothionein levels implied low metal contamination.     

Greener growing: assessing the influence of gardening practices on the ecological viability of community gardens in South East Queensland,Australia

While claims about the environmental benefits of community gardens abound, few researchers have systematically assessed the ecological integrity of gardening practices. This study investigated gardening practices in 50 community gardens in Brisbane and Gold Coast cities, Australia. The study aimed to better understand how gardening practices might affect the ecological viability of community gardens. Factors investigated included: garden bio-physical characteristics, operators’ motivations, gardeners’ socio-demographic backgrounds, garden facilities and types of plants grown. Two broad types of gardens were identified: permaculture (21 gardens) and non-permaculture (29 gardens). Permaculture gardens used lower-impact gardening practices. Findings have policy implications for environmental planning and management.     

Management by Assertion: Beavers and Songbirds at Lake Skinner (Riverside County,California)

Management of ecological reserve lands should rely on the best available science to achieve the goal of biodiversity conservation. “Adaptive Resource Management” is the current template to ensure that management decisions are reasoned and that decisions increase understanding of the system being managed. In systems with little human disturbance, certain management decisions are clear; steps to protect native species usually include the removal of invasive species. In highly modified systems, however, appropriate management steps to conserve biodiversity are not as readily evident. Managers must, more than ever, rely upon the development and testing of hypotheses to make rational management decisions. We present a case study of modern reserve management wherein beavers (Castor canadensis) were suspected of destroying habitat for endangered songbirds (least Bell’s vireo, Vireo bellii pusillus, and southwestern willow flycatcher, Empidonax traillii extimus) and for promoting the invasion of an exotic plant (tamarisk, Tamarix spp.) at an artificial reservoir in southern California. This case study documents the consequences of failing to follow the process of Adaptive Resource Management. Managers made decisions that were unsupported by the scientific literature, and actions taken were likely counterproductive. The opportunity to increase knowledge of the ecosystem was lost. Uninformed management decisions, essentially “management by assertion,” undermine the long-term prospects for biodiversity conservation.     

Safety in shipping: the human element

INTRODUCTION: There are numerous diverse papers that have addressed issues within maritime safety; to date there has been no comprehensive review of this literature to aggregate the causal factors within accidents in shipping and surmise current knowledge. METHODS: This paper reviewed the literature on safety in three key areas: common themes of accidents, the influence of human error, and interventions to make shipping safer. The review included 20 studies of seafaring across the following areas: fatigue, stress, health, situation awareness, teamwork, decision-making, communication, automation, and safety culture. RESULTS: The review identifies the relative contributions of individual and organizational factors in shipping accidents, and also presents the methodological issues with previous research. CONCLUSIONS: The paper concludes that monitoring and modifying the human factors issues presented in this paper could contribute to maritime safety performance. IMPACT ON INDUSTRY: This review illustrates which human factors issues are prevalent in incidents therefore this gives shipping practitioners a focus for interventions.     

Temporal dynamics of antagonism and mutualism in a geographically variable plant-insect interaction

Variation among sites and years in the local ecological outcome of interspecific interactions can generate a geographic mosaic of coevolution, as indicated by recent mathematical models. We evaluated whether local temporal dynamics of ecological outcome in the interaction between the moth Greya politella (Prodoxidae) and its host plant Lithophragma parviflorum (Saxifragaceae) are likely to mitigate or magnify geographic differences in ecological outcome found in earlier studies. The moths are highly host-specific pollinating floral parasites, and the mutualism can be swamped in some populations by the presence of effective co-pollinators. Hence, differing community contexts can shift the outcome of the interaction from mutualism to commensalism or antagonism. During each of four years, we evaluated the effect of Greya oviposition on seed development through a paired design that controlled for plant genotype and microenvironment. At Turnbull National Wildlife Refuge in Washington State, the interaction was significantly mutualistic in all four years. Mutualism in this population was indicated by a higher probability of development of capsules visited by ovipositing Greya than capsules not visited by Greya on the same plant. At Rapid River, Idaho, the interaction was commensalistic in three years and antagonistic in one year. Antagonism in this population was indicated by selective withering of capsules containing Greya eggs. Overall, the results suggest stable geographic differences in the range of ecological outcomes in this plant-insect interaction under different community contexts.     

Impact of dredged urban river sediment on a Saronikos Gulf dumping site (Eastern Mediterranean): sediment toxicity,contaminant levels,and biomarkers in caged mussels

Impacts of chemical contaminants associated with dumping of dredged urban river sediments at a coastal disposal area in Saronikos Gulf (Eastern Mediterranean) were investigated through a combined approach of sediment toxicity testing and active biomonitoring with caged mussels. Chemical analyses of aliphatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs), Cu, and Zn in combination with the solid phase Microtox® test were performed on sediments. Concentrations of PAHs, AHs, Cu, and Zn as well as multiple biomarkers of contaminant exposure and/or effects were measured in caged mussels. Sediments in the disposal and neighboring area showed elevated PAHs and AHs concentrations and were characterized as toxic by the solid-phase Microtox® test during and after dumping operations. Biomarker results in the caged mussels indicated sublethal effects mainly during dumping operations, concomitantly with high concentrations of PAHs and AHs in the caged mussel tissues. Cu and Zn concentrations in sediments and caged mussels were generally not elevated except for sediments at the site in the disposal area that received the major amount of dredges. High PAHs and AHs levels as well as sublethal effects in the caged mussels were not persistent after termination of operations. The combined bioassay–biomarker approach proved useful for detecting toxicological impacts of dredged river sediment disposal in sediments and the water column. Nevertheless, further research is needed to evaluate whether sediment toxicity will have long-term effects on benthic communities of the disposal area.