Search results for " Stable Isotope"

Stable C and N isotope concentration in several tissues of the loggerhead sea turtle Caretta caretta from the western Mediterranean and dietary impli…

2007

CONCENTRACIÓN DE ISÓTOPOS ESTABLES DE C Y N EN VARIOS TEJIDOS DE LA TORTUGA BOBA CARETTA CARETTA DEL MEDITERRÁNEO OCCIDENTAL E IMPLICACIONES SOBRE LA DIETA. – La concentración isotópica de escudos del caparazón, piel, músculo y sangre de tortuga boba (Caretta caretta) fueron analizados para investigar el patrón de variación entre tejidos y para evaluar la posición de esta especie en las redes tróficas de la cuenca Argelina. La piel presentaba valores más altos de δ13C que el músculo o los escudos del caparazón y éstos presentaban valores más altos que la sangre. En cambio, el músculo presentaba valores más altos de δ15N que la piel, ésta valores más altos que la sangre y ésta valores más al…

Decomposition of Microbial Necromass Is Divergent at the Individual Taxonomic Level in Soil

2021

The turnover of microbial biomass plays an important part in providing a significant source of carbon (C) to soil organic C. However, whether the decomposition of microbial necromass (non-living microbial biomass) in the soil varies at the individual taxa level remains largely unknown. To fill up these gaps, we compared the necromass decomposition of bacterial and archaeal taxa by separating live microbial biomass with 18O-stable isotope probing from dead microbial biomass in soil. Our results showed that most of the microbial necromass at the operational taxonomic unit level (88.51%), which mainly belong to Acidobacteria, Actinobacteria, Gemmatimonadetes, and Proteobacteria, decomposed sig…

Paleoclimatic and Paleoceanographic reconstruction of the Pleistocene-Holocene through the study of planktonic foraminifera of two sedimentary cores …

2017

Planktonic foraminifera as proxies of the Holocene climatic variability (Tyrrhenian, Mediterranean Sea)

2017

Introduction. The focus of this study is the paleoclimatic reconstruction of the southern Tyrrhenian between ~9.2 and 2.9 ka, through the study of planktonic foraminiferal assemblages and stable isotopes, and comparing data with other coeval intervals. Several authors have studied the climatic sensitivity of Holocene planktonic foraminifera in different parts of the Mediterranean. Planktonic foraminifera produce good records of Holocene climatic variability, especially as regards the suborbital events such as Bond events (Bond et al., 1997) and other cooling/warming oscillations. Therefore, the obtained eco-biostratigraphy has allowed us to analyze how climatic forcing influenced sea surfac…

The late Messinian "Lago-Mare" event and the Zanclean Reflooding in the Mediterranean Sea: New insights from the Cuevas del Almanzora section (Vera B…

2020

Abstract The return to normal marine conditions in the Mediterranean Sea after the end of the Messinian Salinity Crisis (MSC), that led to the deposition of thick evaporitic succession followed by settlement of brackish to freshwater conditions of the “Lago-Mare”, is still subject to extensive debate between two opposite scenarios. One scenario implies an abrupt reflooding through the Gibraltar gateway of the Mediterranean Sea previously disconnected from the world ocean and partly desiccated. The second scenario postulates that the Mediterranean Sea kept a high-water level throughout the Messinian Salinity Crisis and was connected continuously to the Atlantic Ocean and to the Paratethys. T…

Assessing anthropogenic pressures on coastal marine ecosystems using stable CNS isotopes: State of the art, knowledge gaps, and community-scale persp…

2015

Abstract In recent decades, the analysis of carbon, nitrogen and sulfur stable isotopes (SIA) has emerged as a powerful, viable methodology for examining food web structure and dynamics, as well as addressing a number of applied issues. Here, we provide a state-of-the-art review of the use of SIA for assessing anthropogenic pressures on natural ecosystems, in order to establish current knowledge gaps and identify promising applications for evaluating the ecological status of marine coastal waters. Specifically, the potential of SIA to provide food web-scale indicators for estimating cumulative anthropogenic pressures is addressed. The review indicates that the methodology has been used for …

An individual-based dataset of carbon and nitrogen isotopic data of Callinectes sapidus in invaded Mediterranean waters

2022

The characterisation of functional traits of non-indigenous and invasive species is crucial to assess their impact within invaded habitats. Successful biological invasions are often facilitated by the generalist diet of the invaders which can modify their trophic position and adapt to new ecosystems determining changes in their structure and functioning. Invasive crustaceans are an illustrative example of such mechanisms since their trophic habits can determine important ecological impacts on aquatic food webs. The Atlantic blue crab Callinectes sapidus is currently established and considered invasive in the Mediterranean Sea where it has been recorded for the first time between 1947 and 19…

Isotopic Niche and Trophic Position of the Invasive Portunid Portunus segnis Forskål, (1775) in Elounda Bay (Crete Island, Eastern Mediterranean)

2022

There is a growing recognition that an advanced understanding of the trophic characteristics of an invasive consumer can provide important information on its ecological impact. In recent years, the blue swimming crab Portunus segnis, one of the earliest Lessepsian invaders, has considerably expanded its distribution range in the Mediterranean Sea, yet, its trophic habits in invaded areas remain scarcely investigated. In this study, we used carbon and nitrogen stable isotopes analysis (SIA) to determine the trophic position and isotopic niche of the crab compared with other representatives of the flora and fauna occurring in Elounda Bay (Crete). P. segnis showed a trophic position of 3.9, hi…

Trophic structure of vermetid reef community: High trophic diversity at small spatial scales

2013

Stable isotopes were used to investigate contributions of autochthonous (i.e. benthic: epilithon and macroalgae) and allochthonous (i.e. pelagic: phytoplankton) organic matter sources to the diet of suspension-feeders, grazers and predators associated to small reef-pools (cuvettes) created by the reef-building species Dendropoma petraeum in the north-western coast of Sicily (Italy). Contributions of potential food sources were calculated using Bayesian mixing-models and integrated to a multivariate approach to highlight the diversity of C and N pathways within Dendropoma cuvettes. Both pelagic and benthic organic matter sources were exploited by benthic consumers, although clear differences…

Stable isotope analysis of trophic niche in two co-occurring native and invasive terrapins, Emys orbicularis and Trachemys scripta elegans

2016

A trophic niche overlap in native and alien turtle species can lead to competitive interactions whereby allochthonous turtles may outcompete autochthonous individuals and eventually affect viability of natural populations. The European pond turtle (Emys orbicularis) is an autochthonous species threatened by habitat encroachment and competition with the red-eared slider (Trachemys scripta elegans). The latter is an invasive species introduced in Europe from midwestern United States as a pet and now widespread in the natural habitats of E. orbicularis. The extent of trophic competition between E. orbicularis and T. s. elegans in northern Italy was assessed by nitrogen and carbon stable isotop…