Search results for "FS"
showing 10 items of 1992 documents
Adjustment time and offset of a system for spatially variable rate fertilisation
2005
The aim of this research is to measure the adjustment time and offset of a cheap system for spatially variable rate fertilisation, designed, developed and set up by the Mechanics Section of I.T.A.F. Department. In order to test the system, a centrifugal fertiliser spreader, working by gravity, was modified connecting an actuator with the two hopper shutter slides. Two different actuator types were tested, in order to measure the accordingly variable adjustment time and offset. The adjustment offset of the centrifugal spreader increases with increasing machine average forward speed and decreases with increasing fertiliser rate, considering the same rate variation. The main components of the …
The Status of Coastal Benthic Ecosystems in the Mediterranean Sea: Evidence From Ecological Indicators
2020
The Mediterranean Sea is subject to multiple human pressures increasingly threatening its unique biodiversity. Spatially explicit information on the ecological status of marine ecosystems is therefore key to an effective maritime spatial planning and management, and to help the achievement of environmental targets. Here, we summarized scientific data on the ecological status of a selection of marine ecosystems based on a set of ecological indicators in more than 700 sites of the Mediterranean Sea. For Posidonia oceanica seagrass beds, rocky intertidal fringe, and coastal soft bottoms, more than 70% of investigated sites exhibited good to high ecological conditions. In contrast, about two-th…
Mapping the potential for offshore aquaculture of salmonids in the Yellow Sea
2022
AbstractMariculture has been one of the fastest-growing global food production sectors over the past three decades. With the congestion of space and deterioration of the environment in coastal regions, offshore aquaculture has gained increasing attention. Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) are two important aquaculture species and contribute to 6.1% of world aquaculture production of finfish. In the present study, we established species distribution models (SDMs) to identify the potential areas for offshore aquaculture of these two cold-water fish species considering the mesoscale spatio-temporal thermal heterogeneity of the Yellow Sea. The values of the a…
Assessing vermetid reefs as indicators of past sea levels in the Mediterranean
2020
Abstract The endemic Mediterranean reef building vermetid gastropods Dendropoma petraeum complex (Dendropoma spp) and Vermetus triquetrus develop bio-constructions (rims) on rocky shorelines at about Mean Sea Level (MSL) and are therefore commonly used as relative sea-level (RSL) markers. In this study, we use elevations and age data of vermetid reefs to (1) re-assess the vertical uncertainties of these biological RSL indicators, and (2) evaluate the vertical growth rates along a Mediterranean east-west transect, in attempt to explain the differences found in both growth rates and uncertainties. In Israel, Differential Global Positioning System (DGPS) and laser measurements relative to the …
Estimation of dynamic energy budget parameters for the Mediterranean toothcarp (Aphanius fasciatus)
2014
Organisms adopt different sets of physiological, behavioural and morphological trade-offs in order to cope with natural environmental fluctuations. This has consequential rebounds on ecological processes and population dynamics. Such aspects become crucial for sex-dimorphic species, where sex-specific growth variation could mirror different tactics both in energy acquisition and investment between maximum female and male body size with cascading effects on population demography. To date, different approaches have been used in order to understand the causes of individual growth rate changes in ectotherm indeterminate growers, most of which failed. Here, we propose the use of a mechanistic mo…
Feeding behaviour of Ophidiaster ophidianus (Lmk.) (Asteroidea) in Mediterranean rocky reefs
2017
The thermophilic Atlanto-Mediterranean purple starfish, Ophidiaster ophidianus, is a species protected under the EU’s Habitats Directive which is expanding its distribution in the northern Mediterranean areas as a consequence of global worming. The ecology of the species is largely unknown, specially for the diet. To cover this gap, the feeding habits of O. ophidianus have been studied in two different Mediterranean rocky reef areas: the southern Tyrrhenian Sea (Ustica Island, sampled in 2009) and the eastern Adriatic Sea (Molunat, sampled in 2014) by both field observations and ?13C and ?15N stable isotope analysis (SIA). SCUBA divers collected data by turning adult starfish downside-up an…
Crostacei Anfipodi associati ai reef di Sabellaria alveolata (Annelida: Sabellariidae) del Canale di Sicilia (Mar Mediterraneo)
2015
We describe diversity and patterns of spatial distribution of the amphipod fauna associated with reefs of the polychaete Sabellaria alveolata (L.) in the Sicily Strait. Samples were collected in June 2013, at three localities. Amphipod assemblages appeared homogeneous in the study area with variability increasing with decreasing spatial scale of observation. Jassa ocia (Bate) and Gammaropsis ulrici Krapp-Schickel & Myers characterized the studied assemblages.
Analysis and assessment of trace element contamination in offshore sediments of the Augusta Bay (SE Sicily): A multivariate statistical approach base…
2014
Abstract An application of multivariate statistical methods is provided to identify anthropogenic contaminants and lithogenic elements in offshore sediments collected near the heavily industrialized Augusta Bay, Sicily. An exploratory statistical technique, based on canonical correlation analysis (CCA) and mixture density estimation approach, is used for distinguishing between natural and anthropogenic contributions of trace elements in the investigated sediments. Following the intensive industrialization of Augusta area, marine sediments reveal the severe impact of local anthropogenic activities for many elements (e.g. As, Cd, Hg, Pb, and Sb), which are considered very dangerous for the en…
Temporal dynamic of biofilms enhances the settlement of the central-1 Mediterranean reef2 builder Dendropoma cristatum (Biondi, 1859)
2021
Research on marine invertebrate settlement provides baseline knowledge for restoration technique implementation, especially for biogenic engineers with limited dispersion ability. Previously, we determined that the maturity of a biofilm strongly enhances the settlement of the vermetid reef-builder Dendropoma cristatum . In order to elucidate which biofilm features support a higher settlement of this species, we analyse the structure and composition of a marine biofilm over time, through microscopic observations, eukaryotic and prokaryotic fingerprinting analyses and 16S rDNA Illumina sequencing. The vermetid settlement temporal increase matched with the higher biofilm extent on the substrat…