Search results for " Stable Isotope"

Marble and stone revetment and pavements: Context and provenance

2022

Earlier excavations and survey at Vagnari furnished hardly any evidence for the use of marble at the site, and so the vicus was considered to be a low status settlement, with only a few rooms having been elegant enough to decorate them with marble floors or revetment. The fragments recovered were not analysed scientifically to determine the location of the quarries from which the marbles came. Of particular interest, however, were two small fragments of inscriptions on white marble retrieved from the rubble fill dumped in the 4th century AD in the reservoir. These originally may have been attached, when intact, to votive or funerary monuments, suggesting that the occasional commemorative mo…

Nitrogen stable isotopes as tracers of biodeposition from a tuna farm in the Western Mediterranean

2007

Sea-level changes during the last 41,000 years in the outer shelf of the southern Tyrrhenian Sea: Evidence from benthic foraminifera and seismostrati…

2011

Abstract An integrated high resolution study based both on a seismostratigraphic approach and on a sedimentary core (VIB 10), collected in the outer shelf (127 m depth) from the southern Tyrrhenian Sea (Gulf of Termini, Sicily), provides new data about climatic, eustatic and paleoenvironmental changes during the last ∼41,000 years. The results based on the interpretation of a seismic profile, on benthic foraminifera assemblages and on δ18O records, allowed recognition of two drastic sea-level falls during the Last Glacial Maximum (LGM) and the Younger Dryas (YD). The short deglacial event, between LGM and YD, known as Bolling/Allerod, played an important role in the sea-level rise that prod…

Water stable isotope data set in temperate, lowland catchment, two years of monthly observations, River Salaca, Latvia

2020

Highlights • Two years of monthly water stable isotope ratios from temperate lowland catchment. • Hourly water table, temperature and electrical conductivity monitoring. • Distinct isotope ratios for raised bog, groundwater and rivers.

Plasticity in the trophic niche of an invasive ant explains establishment success and long‐term coexistence

2021

Invasive species are one of the main threats to biodiversity worldwide and the processes enabling their establishment and persistence remain poorly understood. In generalist consumers, plasticity in diet and trophic niche may play a crucial role in invasion success. There is growing evidence that invasive ants, in particular, occupy lower trophic levels in their introduced range compared to the native one, but evidences remain fragmented. We conducted stable isotope analysis at five locations distributed on two continents to infer the trophic position of the invasive ant Formica paralugubris in the native and introduced part of the range. This species forms large colonies and can be a vorac…

Lake zooplankton δ13C values are strongly correlated with the δ13C values of distinct phytoplankton taxa

2016

Analyses of carbon stable isotopes are often used to estimate the contributions of allochthonous and autochthonous dietary resources to aquatic consumers. Most pelagic food web studies assume that all phytoplankton taxa have a similar δ13C value. We studied pelagic food web compartments (dissolved inorganic carbon [DIC], phytoplankton, bacteria, seston, cladoceran zooplankton) in 12 small (< 0.1 km2) lakes in southern Finland. These lakes were classified as oligotrophic, mesotrophic, eutrophic, and dystrophic based on their concentrations of total phosphorus and dissolved organic carbon. Additionally, we studied phytoplankton photosynthetic carbon fractionation (εp) in laboratory conditions…

Use of stable isotopes to investigate dispersal of waste from fish farm as a function of hydrodynamics.

2006

Stable isotopes were used to examine differential effects of fish farm waste on the water column and sediments. To achieve this objective, we chose 3 marine fish farms located along the coast of Sicily (Mediterranean Sea) as point-source disturbances, and a control area. The hypothesis that carbon and nitrogen isotope composition of particulate (POM) and sedimentary (SOM) organic matter varied with increasing distance (from cages to 1000 m) was tested at 3 levels of hydrodynam- ics: low (mean velocity of current (MVC) ~12 cm s -1 ), intermediate (MVC ~22 cm s -1 ), and high (MVC ~40 cm s -1 ). Different isotopic signals from allochthonous (fish waste) over natural (phytoplankton, terrigenou…

Role of peat organic matter on isotopic composition of most abundant benthic organisms in intertidal habitats of SW Iceland

2008

The transfer of peat organic matter (OM) from tidal pools of upper littoral to downstream rocky shores and its potential incorporation into marine biota were investigated using the stable isotope approach. Samplings were carried out in September 2004 in two SW Icelandic sites (Osar and Hvassahraun), where we selected (1) areas with shores where grass gently declined towards rocks and, on reaching the sea line, formed small tidal peat pools and (2) areas where grass and rocky shores were not contiguous, rather the grass lower limits were several hundreds of meters back from the shore. In both grass and no grass areas, in the intertidal zone, all benthic organisms and all potential OM sources…

Sources of organic matter for inter-tidal consumers in Ascophyllum-shores (Sw Iceland): a multi stable isotope approach.

2007

Stable isotopes were used to examine the origin of organic matter in Icelandic Ascophyllum-based habitats, the role of different organic matters in filling intertidal food webs and the food preferences of the most abundant suspension feeders, grazers and predators. We selected three intertidal sites on the SW coast of Iceland where we sampled in early September 2004, organic matter sources (POM, SOM and most abundant primary producers, A. nodosum and F. vesciculosus) and the most abundant macrofauna species (barnacles, mussels, gastropods, sponge and crabs). Even though the primary production (Ascophyllum-based) was the same at the three study sites, the isotopic composition of common-among…

Trophic habits of Muscardinus avellanarius (Mammalia Gliridae) as revealed by multiple stable isotope analysis

2007

Multiple stable isotope analysis was used to investigate the diet of the common dormouse Muscardinus avellanarius in a mixed Mediterranean forest. δ13C and δ15N values of dormouse tissues compared to those of the vegetal and animal sources available in the area showed that the isotopic composition of both adult and juvenile M. avellanarius could be explained by a mixture of vegetal and animal organic matter. The isotopic composition of the assimilated nitrogen was mostly explained by the organic matter from flora. Among the vegetal components, flowers of Fagus silvatica, Quercus robur, and the rarer Crataegus oxyacantha, berries of Ilex aquifolium and acorns of Q. robur were found in the ad…