Search results for "Sedimentary"

Initial Fish-Farm Impact on Meiofaunal Assemblages in Coastal Sediments of the Western Mediterranean

1999

We studied the initial impact of organic loads due to the biodeposition of a new fish farm in a non-impacted coastal area of the Tyrrhenian Sea (Western Mediterranean). Sediment chemistry and meiofaunal assemblages were investigated from July 1997 to February 1998 on a monthly basis at two stations: the first was located under the fish farm, while the second was at about 1 km distance, and served as control. Variations in the biochemical composition of the sedimentary organic matter and meiofaunal community structure were also related to changes in reared fish biomass. The presence of the cage-induced rapid changes in the benthic compartment: the sediments reached rapidly (i.e., after only …

Sedimentary and particulate organic matter: mixed sources for cockleCerastoderma glaucumin a shallow pond, Western Mediterranean

2007

Seasonal changes in feeding habits and diet of the cockle Cerastoderma glaucum (Mollusca, Bivalvia) were analysed using carbon (δ 13 C) and nitrogen (δ 15 N) stable isotopes. I aimed to investigate the role of benthic and pelagic sources in the diet of this dominant infaunal bivalve on a western Mediterranean sandy bottomed pond. Adult C. glaucum and all potential organic sources (particulate and sedimentary organic matter, seagrass, macroalgae, het- erotrophic detritus) were collected and analysed for δ 13 Ca ndδ 15 N. In total 5 dominant organic sources were found, ranging between -21.0 and -8.0%� for δ 13 C and from 3.0 to about 7.0%� for δ 15 N. C. glaucum assimilated fraction ranged be…

Aquaculture impact on benthic microbes and organic matter cycling in coastal Mediterranean sediments: a synthesis

2003

Microbial assemblages and organic matter composition as well as their response to the disturbance induced by mussel and fish-farm biodeposition were compared in several areas of the Mediterranean: La Spezia (Ligurian Sea), Gaeta (Tyrrhenian Sea), Cattolica (Adriatic Sea) and Cyprus (Levantine Sea), on both unvegetated and Posidonia bed sediments. In all systems investigated, organic matter (as biopolymeric carbon) accumulated in aquaculture impacted sediments. Among the main biochemical classes, lipids appeared to be a good tracer of aquaculture impact, especially in fish-farm sediments. Exoenzymatic activities displayed higher values in sediment beneath the cages, indicating faster organic…

Seasonal and spatial changes in the sediment organic matter of a semi-enclosed marine system (W-Mediterranean Sea)

1999

The composition of sediment organic matter and the related role of microphytobenthic biomass have been investigated during one-year in a semi-enclosed marine system (Marsala lagoon, Mediterranean Sea). Monthly samples from June 1993 to May 1994 were analysed for carbohydrate, protein, lipid, photosynthetic pigment and total organic matter. The three main biochemical classes of organic compounds (i.e. carbohydrates, proteins and lipids) showed higher concentrations than reported in the literature. However, photosynthetic pigment was quite low, compared to other enclosed marine basins or Mediterranean coastal lagoons. As a result, the contribution of primary organic carbon to the sedimentary …

Sources and transfer of organic matter in food webs of a Mediterranean coastal environment: Evidence for spatial variability

2006

Abstract The spatial variability in the food web structure of a Mediterranean semi-enclosed coastal environment (Stagnone di Marsala, Italy) was investigated using stable carbon and nitrogen isotopes. Organic matter sources and consumers were sampled in two locations with different environmental features (e.g. hydrodynamic regime, open-sea influence, vegetal coverage). Overall more 13 C-enriched and 15 N-depleted values were found in the central location than in the southern for organic matter sources and consumers. Pelagic consumers (zooplankton and juveniles of transient fish) showed slight spatial differences and in both locations seemed to depend on phytoplankton as the ultimate energy …

Effects of fish farming waste to sedimentary and particulate organic matter in a southern Mediterranean area (Gulf of Castellammare, Sicily): a multi…

2004

Abstract Carbon and nitrogen stable isotope analysis was used to investigate the dispersion area of waste material coming from fish farming activities in the western Mediterranean. Tests were conducted to see if uneaten feed and faecal material isotopic signals, originating from fish farms, could be detected in particulate organic matter (POM) and sedimentary organic matter (SOM). The detectable dispersion distance (from under cages as far as 1000 m) of cage-derived organic material was also examined. To do this, carbon (δ13C) and nitrogen (δ15N) composition in POM and SOM collected around the cages, in some control areas and in the waste material, was measured. Mean POM δ13C was −22.9±0.2‰…

Stable carbon and nitrogen ratios (δ13Corg and δ15Ntot) of core sediments from the Gulf of Palermo (NW Sicily): implications for the carbon source

2010

The Messinian Salinity Crisis deposits in the Balearic Promontory: An undeformed analog of the MSC Sicilian basins??

2021

International audience; The Messinian Salinity Crisis (MSC) is a controversial geological event that influenced the Mediterranean Basin in the late Miocene leaving behind a widespread Salt Giant. Today, more than 90% of the Messinian evaporitic deposits are located offshore, buried below the Plio-Quaternary sediments and have thus been studied mainly by marine seismic reflection imaging. Onshore-offshore records’ comparisons and correlations should be considered a key approach to progress in our understanding of the MSC.This approach has however not been widely explored so far. Indeed, because of the erosion on the Messinian continental shelves and slopes during the MSC, only few places in …

The Messinian salinity crisis in the Mediterranean basin: A reassessment of the data and an integrated scenario

2006

Abstract After a long period of controversial debate about the interpretation of the Messinian salinity crisis (MSC), a near consensus existed since the ODP Leg 42A for a model keeping the major lines of the deep basin-shallow water model initially proposed by Hsu et al. (1973) . The knowledge of the crisis was improved since the 1995s by the availability of a very accurate astronomically calibrated timescale. The debate about its interpretation was then reactivated by several new scenarios that questioned most the major aspects of the previous classical models. The updated re-examination of the most salient features along with consideration of the hydrological requirements for evaporite de…

Syn-sedimentary tectonics during early Pliocene time in the northern Madonie Mountains (Sicily

2008

Tettonica sinsedimentaria del Pliocene inferiore nei Monti delle Madonie settentrionali (Sicilia). L'analisi stratigrafico-strutturale condotta in un piccolo bacino infra-pliocenico nelle Madonie settentrionali (Lascari-Capo Plaja) permette di descrivere un evento tettonico sin-sedimentario. La sinclinale EW in cui si sviluppa il bacino sintettonico appartiene ad un sistema di pieghe nord vergenti che deformano un piano di sovrascorrimento più antico (Langhiano-Serravalliano). La geometria di crescita che caratterizza il pattern stratale dei depositi pliocenici e la discordanza angolare alla base suggeriscono che la nucleazione di queste strutture compressionali si possa essere realizzata a…