Search results for "lcsh:Science"
showing 10 items of 2187 documents
Costs and Benefits of Experimentally Induced Changes in the Allocation of Growth versus Immune Function under Differential Exposure to Ectoparasites
2010
Background Ecological immunology has focused on the costs of investment in immunocompetence. However, understanding optimal resource allocation to immune defence requires also identification of its benefits, which are likely to occur only when parasites are abundant. Methodology We manipulated the abundance of parasitic hen fleas in blue tit (Cyanistes caeruleus) nests, and supplemented their hosts, the nestlings, with methionine (a sulphur amino acid enhancing cell-mediated immunity) during day 3–6. We found a significant interaction between these two experimental factors on the development of immune defences and growth rates. Only in parasitized nests did methionine supplementation boost …
A spatially explicit risk assessment approach: Cetaceans and marine traffic in the Pelagos Sanctuary (Mediterranean Sea).
2017
15 páginas, 5 figuras, 2 tablas.-- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Effect of Multiple Parasitic Infections on the Tolerance to Pollutant Contamination
2012
8 pages; International audience; The horizontally-transmitted acanthocephalan parasite Polymorphus minutus and the vertically-transmitted microsporidian parasite Dictyocoela roeselum have both been shown to influence on the antitoxic responses of mono-infected Gammarus roeseli exposed to cadmium. The present study investigates the effect of this co-infection on the antitoxic defence responses of naturally infected females exposed to cadmium stress. Our results revealed that, depending on the cadmium dose, bi-infection induced only slight, significant increased cell damage in G. roeseli as compared to non-infection. In addition, the antitoxic defence pattern of cadmium-exposed bi-infected ho…
Predation on Multiple Trophic Levels Shapes the Evolution of Pathogen Virulence
2009
The pathogen virulence is traditionally thought to co-evolve as a result of reciprocal selection with its host organism. In natural communities, pathogens and hosts are typically embedded within a web of interactions with other species, which could affect indirectly the pathogen virulence and host immunity through trade-offs. Here we show that selection by predation can affect both pathogen virulence and host immune defence. Exposing opportunistic bacterial pathogen Serratia marcescens to predation by protozoan Tetrahymena thermophila decreased its virulence when measured as host moth Parasemia plantaginis survival. This was probably because the bacterial anti-predatory traits were traded o…
Interaction between Medicago truncatula and Pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric CO2.
2012
10 pages; International audience; Soil microorganisms play a key role in both plants nutrition and health. Their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. These interactions involved the liberation of plant organic compounds via rhizodeposition. Modification of atmospheric CO2 concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. Positive effect of elevated CO2 on plants are rather well known but consequences for micoorganisms and their interactions with plants are still poorly understood. A gnotobiotic system has been devel…
Key Economic Characteristics of Italian Trawl Fisheries and Management Challenges
2017
Two key measures of economic performance are calculated and analyzed for three important Italian trawl fisheries (Northern Thyrrenian Sea, South of Sicily, Northern Adriatic Sea): the Net Economic Returns (NER), which informs on the economic performance and is considered a proxy of resource rent in fisheries and the Return on Fixed Tangible Assets (ROFTA), which is used as an approximation of the Return on Investment (ROI) and is a key financial and performance indicator for a fisherman in order to take a decision to operate in a fishery. The trend of these indicators over the last decade highlights a poor economic performance that is associated with an overall poor condition of the state o…
Novel Insights Into Gas Embolism in Sea Turtles: First Description in Three New Species
2020
The recent finding of gas embolism and decompression sickness in loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea challenged the conventional understanding of marine vertebrate diving physiology. Additionally, it brought to light a previously unknown source of mortality associated with fisheries bycatch for this vulnerable species. In this paper, we use ultrasonography to describe gas embolism in a leatherback sea turtle (Dermochelys coriacea), a green sea turtle (Chelonia mydas) and an olive ridley sea turtle (Lepidochelys olivacea) from accidental capture in a gillnet, bottom trawl and pair-bottom trawl respectively. This is the first description of this condition in thes…
Common Bottlenose Dolphin Protection and Sustainable Boating: Species Distribution Modeling for Effective Coastal Planning
2020
Indicators for preserving marine biodiversity include knowledge of how the spatial distribution and critical habitats of species overlap with human activities and impacts. Such indicators are key tools for marine spatial planning, a process that identifies and resolves conflicts between human uses and the conservation of marine environments. The common bottlenose dolphin in the Mediterranean Sea is considered a vulnerable species by the IUCN Red List and a priority species of the EU Habitat Directive. Here, we estimated spatio-temporal patterns of the species occurrence in the area around one Marine Protected Area (MPA) and two Sites of Community Importance (SCI) of the North western Sardin…
Molecular Systematics of the Long-Snouted Deep Water Dogfish (Centrophoridae, Deania) With Implications for Identification, Taxonomy, and Conservation
2021
According to the most recent taxonomical revision, the deep-sea dogfish genus Deania encompasses four species. Three of them, D. calcea, D. profundorum, and D. hystricosa, occur in the North Atlantic. Whilst D. profundorum can be identified by the presence of a subcaudal keel, the other two species are not easily visually distinguished. Uncertainties over identification raises concerns over stock units and whether management plans are adequate. In this study we compared onboard visual identification of Deania specimens, with morphological inspection of skin denticles under stereo microscope and with independent molecular taxonomical assignment using two molecular markers. Particular emphasi…
Spatiotemporal Dispersal and Deposition of Fish Farm Wastes: A Model Study from Central Norway
2017
Abstract A spatially explicit coupled hydrodynamic-mass transport model system was used to simulate dispersal of particulate organic matter from Atlantic salmon (Salmo salar) farming in central Norway. Model setups of 32 m horizontal resolution were run for periods of up to 650 days for 3 sites of different oceanographic characteristics: one fjord location, one medium-exposed location influenced by fjord water and one coastal location. Records on feed used for each cage at each location were converted to feces released based on a published mass balance model. The results from the simulations were compared with scores from corresponding mandatory benthic surveys (MOM-B) of the sediment layer…