Trophic specialisation of metazoan meiofauna at the Håkon Mosby Mud Volcano: fatty acid biomarker isotope evidence

We report the results of a detailed investigation on the trophoecology of two dominant meiofaunal species at the Håkon Mosby Mud Volcano (HMMV), a deep-sea cold methane-venting seep. Analyses of fatty acids (FAs) and their stable carbon isotopes were used to determine the importance of chemosynthetic nutritional pathways for the dominant copepod species (morphologically very similar to Tisbe wilsoni) inhabiting the volcano’s centre and the abundant nematode Halomonhystera disjuncta from the surrounding microbial mats. The strong dominance of bacterial biomarkers (16:1ω7c, 18:1ω7c and 16:1ω8c) coupled with their individual light carbon isotopes signatures (δ¹³C ranging from ?52 to ?81‰) and the lack of symbiotic relationships with prokaryotes (as revealed by molecular analyses and fluorescent in situ hybridisation) indicated that chemosynthetically derived carbon constitutes the main diet of both species. However, the copepod showed a stronger reliance on the utilisation of methanotrophic bacteria and contained polyunsaturated FAs of bacterial origin (20:5ω3 and 22:6ω3 with isotope signatures δ¹³C < ?80‰). Instead, the FA profiles of H. disjuncta suggested that sulphide-oxidising bacteria constituted the main diet of this nematode. Therefore, HMMV can be regarded as a persistent deep-sea cold seep, allowing a chemosynthesis-based trophic specialisation by the dominant meiofaunal species inhabiting its sediments. The present investigation, through the determination of the fatty acid profiles, provides the first evidence for trophic specialisation of meiofauna associated with sub-habitats within a cold seep.     

‘Here,I'm not at ease’: anthropological perspectives on community resilience

A number of recent studies on disaster reconstruction have focused on the concept of community resilience and its importance in the recovery of communities from collective trauma. This article reviews the contributions the anthropological literature and the ethnographic case studies of two post‐Hurricane Mitch housing reconstruction sites make to the theorising of community and resilience in post‐disaster reconstruction. Specifically, the article demonstrates that communities are not static or neatly bounded entities that remain constant before, during and after a disaster; rather, communities take on shape and qualities depending on the relationships in which they engage with government agencies and aid organisations before and after disasters. Consequently, the article argues that definitions of community resilience and disaster mitigation programmes must take the emergent and relational nature of communities into account in order to address the long‐term causes and impacts of disasters.     

Spatio-temporal analysis of alpine ecotones: A spatial explicit model targeting altitudinal vegetation shifts

There is general agreement in literature that Alpine vegetation belt ecotones have shown a trend of upward migration in the last few decades. Despite the potential of such shifts as indicators of global change effects in mountain ecosystems, there are relatively few works focused on their assessment in a systematic and spatially explicit way. In this work our aim is to quantify the altitudinal shifts and analyse the spatial pattern dynamics of mountain ecotones. We developed a novel procedure to delineate the current and former state of three characteristic mountain ecotones, which we formalised as forest, tree and tundra lines. Our approach is based on the recognition of altitudinal extreme outposts identified with ecotone locations at a slope scale. The integration of multi-temporal datasets allows the identification and quantification of altitudinal advances and retreats in the outpost locations for a given period. We tested the method in a section of the Italian Alps for the period 1957-2003. Results show a general trend of an increase in altitude for the three ecotones, despite the occurrence of occasional decreases. We estimate decadal altitude increments of 25 m for forest line, 13 m for treeline and 11 m for tundra line. We also identified changes in ecotone spatial morphology between the two dates, with significant implications in connectivity and colonisation dynamics.     

Food supplementation affects egg albumen content and body size asymmetry among yellow-legged gull siblings

Parental decisions can determine offspring experience of environmental conditions. Such ‘maternal’ effects act both before and after hatching via, e.g., egg quality or the social milieu predisposed by parents. Resource availability may constrain the expression of adaptive maternal effects, and the specific pattern of allocation of these effects among offspring depending on their sex or birth order can result in different fitness payoffs to parents. Declining egg mass with laying order observed in several bird species may constitute an adaptive strategy of parental favouritism towards early hatching offspring with larger reproductive value but may also result from nutritional constraints on laying effort. A previous study has shown that the small size of the third, last laid (c-)egg in yellow-legged gull (Larus michahellis) clutches depends on food availability and that food-supplemented mothers increase the size of their female but not male c-eggs. Here, we show that increased mass of c-eggs laid by females supplemented with food after clutch initiation depends on increased albumen mass, which, in turn, enhances the size of daughters at hatching. Because asynchronous hatching results in a competitive disadvantage of c-chicks, present results suggest that mothers relieved from nutritional constraints enhance the size of daughters to compensate for their larger susceptibility to hatching last. The study also confirms the role of egg albumen content in determining hatchling size, previously experimentally detected only in one species in the wild. The effect of increased egg mass on offspring size persisted at least until day 8 after hatching, when, however, it did not vary with sex, suggesting intense negative selection on small female c-chicks in control broods. Hence, maternal effects mediated by egg albumen content had persistent effects on offspring size.     

Dynamic respiration index as a descriptor of the biological stability of organic wastes

Analytical methods applicable to different organic wastes are needed to establish the extent to which readily biodegradable organic matter has decomposed (i.e., biological stability). The objective of this study was to test a new respirometric method for biological stability determination of organic wastes. Dynamic respiration index (DRI) measurements were performed on 16 organic wastes of different origin, composition, and biological stability degree to validate the test method and result expression, and to propose biological stability limits. In addition, theoretical DRI trends were obtained by using a mathematical model. Each test lasted 96 h in a 148-L-capacity respirometer apparatus, and DRI was monitored every hour. The biological stability was expressed as both single and cumulative DRI values. Results obtained indicated that DRI described biological stability in relation to waste typology and age well, revealing lower-stability waste characterized by a well-pronounced DRI profile (a marked peak was evident) that became practically flat for samples with higher biological stability. Fitting indices showed good model prediction compared with the experimental data, indicating that the method was able to reproduce the aerobic process, providing a reliable indication of the biological stability. The DRI can therefore be proposed as a useful method to measure the biological stability of organic wastes, and DRI values, calculated as a mean of 24 h of the highest microbial activity, of 1000 and 500 mg O(2) kg(-1) volatile solids (VS) h(-1) are proposed to indicate medium (e.g., fresh compost) and high (e.g., mature compost) biological stabilities, respectively.     

The Determination of Heavy Metals in the Ligurian Sea. III. Distribution of Copper, Iron, and Nickel in the 0-200 Metre Layer in Open Sea

Dissolved Cu, Fe and Ni were determined in sea water samples from 9 stations in the Ligurian Sea located along the two traverses Imperia-Capo Corso and Nice-Calvi and at depths between 0 and 200 m. The samples were preconcentrated from small volumes of sea water by complexation with ammonium pyrrolidine-dithiocarbammate (APDC), extraction with CCl₄ and determination by AAS with electrothermal atomisation. The geographical distribution shows that in the central part of the inner traverse there is a maximum of Cu and Fe concentration; the vertical distribution shows no significant depletion of the dissolved elements in the epithalassa.

The results allow for a first approach to the more general problem of the distribution of the trace elements in the Ligurian Sea.     

Economy-wide impacts of climate change: a joint analysis for sea level rise and tourism

While climate change impacts on human life have well defined and different origins, the interactions among the diverse impacts are not yet fully understood. Their final effects, however, especially those involving social-economic responses, are likely to play an important role. This paper is one of the first attempts to disentangle and highlight the role of these interactions. It focuses on the economic assessment of two specific climate change impacts: sea-level rise and changes in tourism flows. By using a Computable General Equilibrium (CGE) model the two impacts categories are first analysed separately and then jointly. Considered separately, in 2050, the forecasted 25 cm. of sea level rise imply a GDP loss ranging from (−) 0.1% in South East Asia to almost no loss in Canada, while redistribution of tourism flows – which in terms of arrivals favours Western Europe, Japan, Korea and Canada and penalises all the other world regions – triggers GDP losses ranging from (−) 0.5% in Small Island States to (−) 0.0004% in Canada. GDP gainers are Australia, New Zealand, Western Europe, Middle East and South Asia. The impact of sea level rise and tourism were simulated jointly and the results compared with those of the two disjoint simulations. From a qualitative point of view, the joint effects are similar to the outcomes of the disjoint exercises; from a quantitative perspective, however, impact interaction does play a significant role. In six cases out of 16 there is a detectable (higher than 2% and peaking to 70%) difference between the sum of the outcomes in the disjoint simulation and the outcomes of the joint simulations. Moreover, the relative contribution of each single impact category has been disentangled from the final result. In the case under scrutiny, demand shocks induced by changes in tourism flows outweigh the supply-side shock induced by the loss of coastal land.

Effectiveness of aerobic pretreatment of municipal solid waste for accelerating biogas generation during simulated landfilling

Effect of aerobic pretreatment of MSW on landfill gas generation was investigated. Volatile solid (VS) loss of MSW is an effective and comparable indicator. Chinese MSW requires at least a reduction of VS about 27% (w/w) prior to disposal. Aerobic pretreatment of MSW reduced lag phase more than 90% before methanogenesis. Aerobic pretreatment degree influences quantity of gas generation. This study evaluates the effectiveness of aerobic pretreatment of municipal solid waste (MSW) on reducing lag phase and accelerating biogas generation. Aerobic pretreatment degree (APD) was determined on the basis of reduction in volatile solids (VS) on a wet weight basis. In this study, intermittent aeration (IA) was applied to three reactors as a main aeration mode; since a single reactor was operated under continuous aeration mode. However, the purpose of the experiment was to reduce VS content of waste, irrespective of the comparison between aeration modes. Fresh MSW was first pretreated aerobically with different aeration rates (10, 40, 60 and 85 L/min/m³) for the period of 30–50 days, resulting in VS-loss equivalent to 20%, 27%, 38% and 53% on w/w basis for the wastes A1, A2, A3 and A4, respectively. The cumulative biogas production, calculated based on the modified Gompertz model were 384, 195, 353, 215, and 114 L/kg VS for the wastes A0, A1, A2, A3 and A4, respectively. Untreated waste (A0) showed a long lag phase; whereas the lag phases of pretreated MSW were reduced by more than 90%. Aerobically pretreated wastes reached stable methanogenic phase within 41 days compared to 418 days for untreated waste. The waste mass decreased by about 8% to 27% compared to untreated MSW, indicative that even more MSW could be placed in the same landfill. The study confirmed the effectiveness of aerobic pretreatment of MSW prior to landfilling on reducing lag phase and accelerating biogas generation.     

Human disturbance and shifts in vertebrate community composition in a biodiversity hotspot

Understanding how human modification of the landscape shapes vertebrate community composition is vital to understanding the current status and future trajectory of wildlife. Using a participatory approach, we deployed the largest camera-trap network in Mesoamerica to date to investigate how anthropogenic disturbance shapes the occupancy and co-occurrence of terrestrial vertebrate species in a tropical biodiversity hotspot: the Osa Peninsula, Costa Rica. We estimated species richness in different categories of land protection with rarefaction analysis and estimated the expected occupancy with a joint species distribution model that included covariates for anthropogenic disturbance, land protection, habitat quality, and habitat availability. Areas with the most stringent land-use protections (e.g., Corcovado National Park, 24 species [95% CI 23–25]) harbored significantly more species than unprotected areas (20 species [19.7–20.3]), mainly due to a reduced presence of large-bodied species of conservation concern in unprotected areas (e.g., jaguar Panthera onca and white-lipped peccary Tayassu pecari). Small-bodied generalist species, such as opossums (Didelphidae) and armadillos (Dasypus novemcinctus), in contrast, were more common at disturbed sites, resulting in a significant difference in vertebrate community composition between sites with low and high disturbance. Co-occurrence of species was also mainly associated with response to disturbance. Similar responses to disturbance create two groups of species, those whose site-level occupancy usually increased as anthropogenic disturbance increased and those whose estimated occupancy decreased. The absence of large-bodied species entails an important loss of ecological function in disturbed areas and can hinder forest development and maintenance. Efforts to protect and restore forested landscapes are likely having a positive effect on the abundance of some threatened species. These efforts, however, must be sustained and expanded to increase connectivity and ensure the long-term viability of the wildlife community.