Detoxification mechanisms in shrimp: comparative approach between hydrothermal vent fields and estuarine environments     

Gonzalez-Rey M  Serafim A  Company R  Gomes T  Bebianno MJ 《Marine environmental research》2008,66(1):35-37

Hydrothermal vents are extreme deep-sea habitats that, due to their singular features, still intrigue scientific communities. Swift growth rates and profuse biomass of biological communities can be observed, despite of their inherently unstable physical-chemical and toxic conditions, indicating that organisms inhabiting this environment must be well adapted to these inhospitable conditions. The caridean shrimp, Chorocaris chacei, Mirocaris fortunata and Rimicaris exoculata, together with bathymodiolid mussels, dominate the vent fauna along the Mid-Atlantic Ridge (MAR). Crustacean species are widely used as biological indicators of environmental alterations, since they play a key ecological role as planktivorous grazers, epibenthic scavengers or as prey species. The biological consequences of the hydrothermal metal-rich environment in shrimp species are still largely unknown. Therefore, the aim of this study was the determination of the metal levels (Ag, Cd, Cu, Fe, Mn and Zn), metallothioneins (MT) and lipid peroxidation (LPO) in shrimp species collected in Rainbow, Lucky Strike and Menez-Gwen vent sites, in order to evaluate their different adaptation strategies toward metals when compared with two common coastal shrimp species (Palaemon elegans and Palaemonetes varians) from a fairly unpolluted estuarine system in south Portugal (Ria Formosa). Results show significant differences in metal concentrations, MT levels and lipid peroxidation between vent and coastal shrimp and also between shrimp species from the same site. This indicates that biochemical responses in both vent and coastal shrimp are affected not only by the environmental characteristics but also by inter-specific differences. Nevertheless, these responses apparently grant a successful adaptation for the survival in a metal-extreme environment.  相似文献   

Is being in work good for wellbeing? Work Integration Social Enterprises in regional Australia     

Katharine McKinnon  Melissa Kennedy  Jo Barraket  Tracy DeCotta 《The Australian geographer》2020,51(3):361-375

ABSTRACT

Work Integration Social Enterprises (WISE) offer supported work environments for people experiencing disadvantage, including people with disability. This paper reflects on a research project that is mapping the ways in which social enterprises in regional Australian cities produce wellbeing for their employees. Through supported employment programs, these organisations are transforming individual lives, helping to build a sense of self-worth and purpose, and increase individuals’ social skills and capacities. Many of the perceived benefits are associated with a belief in the innate good of paid work. Based upon interviews with employees in the social enterprises, it is apparent that the hopes attached to providing ‘meaningful work’ are considerable. At the same time social enterprises are taking on social responsibilities that were once provided by the state, while also selling their services as employers of disabled and disadvantaged members of society and maintaining commercial viability of the enterprise. Using feminist political economy alongside discussion of the distributive economy, this paper explores how contemporary policy conditions, productivist biases and normative discourses about the value of wage work inflect the forms of wellbeing that can be experienced by WISE workers.  相似文献   

The Local Ensemble Transform Kalman Filter (LETKF) with a Global NWP Model on the Cubed Sphere     

Seoleun Shin  Ji-Sun Kang  Youngsoon Jo 《Pure and Applied Geophysics》2016,173(7):2555-2570

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Automatic Semivariogram Modeling by Convolutional Neural Network     

Jo  Honggeun  Pyrcz  Michael J. 《Mathematical Geosciences》2022,54(1):177-205

Mathematical Geosciences - Modeling the semivariogram to characterize spatial continuity requires expert geostatistical knowledge and domain expertise about the spatial phenomenon of interest....  相似文献   

Distribution and feeding patterns of juvenile parrotfish on algal‐dominated coral reefs          下载免费PDF全文

João L.L. Feitosa  Beatrice P. Ferreira 《Marine Ecology》2015,36(3):462-474

By the consumption of algae, parrotfishes open space for young coral settlement and growth, thus playing a central role on the maintenance of coral reefs. However, juvenile parrotfish ecology is often overlooked due to the difficulty discerning species during this phase. Herein, we present the first attempt to investigate changes in habitat use and diet that happen to juveniles of the Redeye parrotfish Sparisoma axillare, focusing on four zones within an algal‐dominated reef: the macroalgal beds, back reef, reef flat, and fore reef. Smaller S. axillare juveniles (<5 cm) preferred to inhabit the macroalgal beds and the reef flat, whereas juveniles larger than 5 cm were more abundant in the back and fore reefs due to distinct post‐settlement habitat conditions. Aggressive interactions with the territorial damselfish Stegastes fuscus were the primary driving factor of juvenile distribution and feeding rates. Attack rates increased with juvenile size and the lowest bite rates were observed in zones with higher densities of territorial damselfish. In previous studies, the persistence of parrotfish recruits in habitats dominated by damselfish was reduced, but newly settled parrotfish occurred more densely within the damselfish domain by behaving as a cryptic reef fish. As these juveniles grew, their bite rates increased, a change associated with a shift from cryptic to roving behavior. Feeding preferences were determined by substrate cover, where juveniles fed on available food sources in each habitat. Juveniles relied on jointed calcareous algae in habitats dominated by these algae, a pattern not observed for thick leathery algae. Filamentous algae were the preferred food for smaller fish; for individuals greater than 10 cm, a higher ingestion of sand was observed. Most studies evaluating the functional role of parrotfish do not consider species feeding preferences. However, the potential for a species to turn an impacted reef back to a coral‐dominated phase is influenced by their food selection, which is dependent on the algal species composition.  相似文献   

Mass segregation in young clusters: observational biases     

Joana Ascenso  João Alves  Maria Teresa V. T. Lago 《Astrophysics and Space Science》2009,324(2-4):113-119

We investigate the validity of the mass-segregation indicators most commonly used in the analysis of young stellar clusters. We construct and analyze synthetic massive clusters with a standard, fully sampled stellar initial mass function and a King density distribution function. We find that the commonly used indicators are highly sensitive to the effects of incompleteness in observational data, and that completeness determinations do not provide satisfactory corrections, leading to results that may be severely biased toward mass segregation.  相似文献   

The Value of Information in Spatial Decision Making   总被引：1，自引：1，他引：0  

Debarun Bhattacharjya  Jo Eidsvik  Tapan Mukerji 《Mathematical Geosciences》2010,42(2):141-163

Experiments performed over spatially correlated domains, if poorly chosen, may not be worth their cost of acquisition. In this paper, we integrate the decision-analytic notion of value of information with spatial statistical models. We formulate methods to evaluate monetary values associated with experiments performed in the spatial decision making context, including the prior value, the value of perfect information, and the value of the experiment, providing imperfect information. The prior for the spatial distinction of interest is assumed to be a categorical Markov random field whereas the likelihood distribution can take any form depending on the experiment under consideration. We demonstrate how to efficiently compute the value of an experiment for Markov random fields of moderate size, with the aid of two examples. The first is a motivating example with presence-absence data, while the second application is inspired by seismic exploration in the petroleum industry. We discuss insights from the two examples, relating the value of an experiment with its accuracy, the cost and revenue from downstream decisions, and the design of the experiment.  相似文献   

Is there a win–win scenario for marine nature conservation? A case study of Lyme Bay,England     

Siân E. Rees  Martin J. Attrill  Melanie C. Austen  Steven C. Mangi  Jo P. Richards  Lynda D. Rodwell 《Ocean & Coastal Management》2010,53(3):135-145

A statutory two hundred and six square kilometre ‘closed area’ in Lyme Bay, South West England entered into force on the 11 July 2008 to protect the reef substrate and the associated biodiversity from the impacts of trawling and dredging with heavy demersal fishing gear. This case study provides an example of how the ecosystem approach has been incorporated into decision making for marine nature conservation and shows that despite sound ecological knowledge of a marine area, the current reliance on traditional neo-classical economic valuations for marine spatial planning can obscure other issues pertinent to the ecosystem approach. With the Government seeking win–win scenarios for stakeholders in the designation of Marine Conservation Zones under the Marine and Coastal Access Act, experience of marine spatial planning in Lyme Bay has revealed that a win–win must be a long-term goal based on a thorough evaluation of the environmental, social and economic values of marine biodiversity.  相似文献   

δ15N and δ13C in the Mondego estuary food web: Seasonal variation in producers and consumers     

Alexandra Baeta  Rute Pinto  Ivan Valiela  Pierre Richard  Nathalie Niquil  João C. Marques 《Marine environmental research》2009,67(3):109-116

Assessments of temporal variation in stable carbon and nitrogen ratios were used to examine seasonal trends of the water column and benthic food webs in the Mondego estuary (Portugal). There was a marked seasonality in weather and water column conditions, including nutrient supply and chlorophyll concentrations. In spite of the pronounced environmental changes, we found little evidence of seasonal variation in δ¹³C and δ¹⁵N of producers and consumers in the Mondego estuary, with a few notable exceptions. Nitrogen isotope ratios in macrophytes (Zostera noltii, Ulva sp., Enteromorpha sp., and Gracilaria sp.), and in two grazers (Idotea chelipes and Lekanesphaera levii) increased during late summer, with the highest δ¹⁵N values being measured in July, during a period of elevated temperatures and drought, which may have favored high rates of denitrification and heavier δ¹⁵N values. The results suggest that stable-isotope values from macrophytes and selected grazers are useful as tracers of seasonal changes in nitrogen inputs into estuaries, and that those of consumers reflect other factors beyond seasonal variations in N and C sources.  相似文献   

Global Paleomagnetic Database Supplement number one: Update to 1992   总被引：3，自引：0，他引：3  

Michael W. McElhinny  Jo Lock 《Surveys in Geophysics》1993,14(3):303-329

This is the first Supplement to the Manual, first published inSurveys in Geophysics in 1991 and issued also as a separate volume, for the operation of the Global Paleomagnetic Database (GPMDB) using ORACL E. Minor changes have been made to the database structure as foreshadowed in the Manual and major extensions have been made to the MENU involving a new set of command files. These and other changes are detailed and should be read in conjunction with the original Manual. This latest Version 2.2 of the the GPMDB now contains over 7000 results with over 2600 references and covers all published data world-wide up to the end of 1992. Diskettes containing the new data set and accompanying program files may be obtained, as before, from World Data Center A in Boulder, Colorado. Both the updated data set and program files completely replace the original Version 1.4 released in August 1991.  相似文献