Search results for "benthic"
showing 10 items of 350 documents
Microbial and meiofaunal response to intensive mussel-farm biodeposition in coastal sediments of the Western Mediterranean
2000
We studied the impact of organic loads due to the biodeposition of a mussel farm in a coastal area of the Tyrrhenian Sea (Western Mediterranean). Sediment chemistry, microbial and meiofaunal assemblages were investigated from March 1997 to February 1998 on monthly basis at two stations: the first was located under the mussel farm, while the second was at about 1-km distance and served as control. Benthic response to changes in the biodepositional regime was investigated in terms of biochemical composition of the sedimentary organic matter, phytopigment content, bacterial abundance and composition and meiofaunal community structure. A large accumulation of chloroplastic pigments, proteins an…
Meiofauna as indicator for assessing the impact of fish farming at exposed marine site
2012
This study aimed to detect the impact of organic loads due to biodeposition from a fish farm in an exposed area of the Strait of Sicily, Mediterranean Sea. Sediment chemistry and meiofaunal assemblages were investigated on a seasonal basis at four stations: two from the impacted area and two control stations. The presence of the cages induced a significant accumulation of proteins, lipids and biopolymeric carbon, resulting in a reduction in meiofaunal density at the impacted stations. Changes in community structure were also evident, as meiofauna under the cages were characterized by increased importance of polychaetes and copepods in comparison with a much lower importance of gastrotrichs …
Benthic microbial indicators of fish farm impact in a coastal area of the Tyrrhenian Sea
2004
Abstract We studied the impact of organic loads due to the biodeposition of a fish farm in a non-impacted coastal area of the Tyrrhenian Sea (Western Mediterranean). Sediment chemistry and benthic microbial community were investigated from July 1997 to February 1998 on monthly basis at two stations: one was located under the fish farm, while the second was about 1 km away, and served as a reference site. The presence of the cage induced rapid changes in the benthic conditions: the sediments were rapidly (after 6 weeks) reduced. A significant accumulation of biopolymeric carbon was observed beneath the cage both 2 weeks after the initial cage deployment, on non-impacted sediments, and 5-7 mo…
Surface and deep water conditions in the Sicily channel (central Mediterranean) at the time of sapropel S5 deposition
2011
New centennial-scale data of benthic foraminifera assemblages and of stable isotopes of foraminifera shells from the Sicily Channel, representative of surface and bottom waters, over the interval between about 140 and 110 kyr BP, are presented. During this period anoxia developed on the eastern Mediterranean basin and sapropel S5 deposited. Although anoxic sediments have not been deposited in the Sicily Channel, this area is strategic to study the character of intermediate waters, whose chemical-physical properties strongly precondition the eastern Mediterranean deep water formation. So far, no data from these water masses have been obtained, apart from the isotopic composition of shells of…
Annual variation of parasite communities of deep-sea macrourid fishes from the western Mediterranean Sea and their relationship with fish diet and hi…
2015
16 pages, 8 figures, 8 tables
Notes on the Biology and Ecology of Opeatogenys gracilis (Canestrini 1864) (Pisces: Gobiesocidae) from Coastal Environments in Sicily (Mediterranean)
2001
A particularly large number of specimens of the Mediterranean coastal fish Opeatogenys gracilis (Canestrini 1864) (Pisces: Gobiesocidae) were collected from Posidonia oceanica mats of the “Stagnone di Marsala” sound (western Sicily) and in the Gulf of Carini (northern Sicily). A study was made of biometric and meristic characters and, for the first time for this species, diet composition. The biometric and meristic data did not distinguish between specimens from the two study sites. In accordance with its benthic habit, O. gracilis feeds on small phytal prey living on Posidonia oceanica leaves. The preferential food items throughout the year were Copepoda Harpacticoida.
Middle Miocene foraminifera from Canals (Valencia, western Mediterranean). Biostratigraphic and palaeoenvironmental aspects
2020
The age and the palaeoenvironmental conditions of the tap marls outcroppings near the locality of Canals in the south of the Valencia Province (E Spain) are discussed. Based on the planktonic foraminifera assemblages, mainly the species Globorotalia praemenardii , these tap marls are dated as Serravallian in age (middle Miocene). The analysis of the foraminiferal assemblages suggests a relatively well-ventilated uppermiddle bathyal environment, with only a moderate oxygen deficiency throughout most of the studied section. The rather cool waters indicated by the planktonic foraminifera (e.g. Globigerina bulloides ) are compatible with the decreasing temperatures trend during the middle Mioce…
Benthic foraminifera and environmental changes in the Quaternary of the western Mediterranean coast: the core of Xeraco, Valencia, Spain
2020
The evolution of the benthic foraminiferal assemblages from a 60 m core drilled in the Quaternary lagoon of Xeraco (Valencia, Spain) is studied. Two moments of warm climate, high sea-level and maximal marine influence in the lagoon have been identified. The first one at the base of the core, punctuated by highly frequent changes during the Upper Pleistocene, and the other one in the upper end of the series during the Holocene. The presence of a middle core section with low diversity and a nearly total absence of marine foraminifers is interpreted as a regressive interval of cold climate conditions linked to a glacial stage.
Contrasting Effects of Environmental Concentrations of Sulfonamides on Microbial Heterotrophic Activities in Freshwater Sediments
2021
The sulfonamide antibiotics sulfamethoxazole (SMX) and sulfamethazine (SMZ) are regularly detected in surface sediments of contaminated hydrosystems, with maximum concentrations that can reach tens of μg kg–1 in stream and river sediments. Little is known about the resulting effects on the exposed benthic organisms. Here we investigated the functional response of stream sediment microbial communities exposed for 4 weeks to two levels of environmentally relevant concentrations of SMX and SMZ, tested individually. To this end, we developed a laboratory channel experiment where natural stream sediments were immersed in water contaminated with nominal environmental concentrations of 500 and 5,0…
Bacterioplankton Community Composition Along Environmental Gradients in Lakes From Byers Peninsula (Maritime Antarctica) as Determined by Next-Genera…
2019
This study comprises the first attempt to describe the planktonic bacterial communities of lakes from Byers Peninsula, one of the most significant limnological districts in the Maritime Antarctica, leveraging next-generation sequencing (NGS) technologies. For the survey, we selected 7 lakes covering the environmental gradient from inland to coastal lakes, some of them sampled both in surface and deep waters. Analysis provided just over 85,000 high quality sequences that were clustered into 864 unique Zero-radius Operational Taxonomic Units (ZOTUs) (i.e., 100% sequence similarity). Yet, several taxonomic uncertainties remained in the analysis likely suggesting the occurrence of local bacteri…