Search results for "sapropel"

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…

A high-resolution record of the last deglaciation in the Sicily Channel based on foraminifera and calcareous nannofossil quantitative distribution

2003

Abstract Relative abundance fluctuations in planktic foraminiferal and calcareous nannofossil assemblages are reported on the basis of a high-resolution study of ODP Leg 160 Hole 963D, drilled in the Sicily Strait, near Capo Rossello (southern Sicily). With its 8 m of undisturbed sediments, the core covers the interval from 1.5 to 23 kyr, allowing a 50–100-yr sampling resolution. All the short warm and cold events and sub-events recorded in this time interval in the GRIP Greenland ice core and at several Mediterranean sites were recognized. On this basis, a total number of nine ecozones based on planktic foraminifera and seven ecozones based on calcareous nannofossils were identified. A sho…

Dynamics at the Strait of Sicily and Mediterranean Sapropels

2012

Ģeogrāfija. Ģeoloģija. Vides zinātne: referātu tēzes

2008

Orbital variations in planktonic foraminifera assemblages from the Ionian Sea during the Middle Pleistocene Transition

2013

Abstract The Middle Pleistocene Transition (1.2–0.7 Ma) is the most recent re-organization of the global climate system which includes variations in the frequency and amplitude of glacial/interglacial cycles, increased ice sheet volume, sea surface temperature cooling and a significant drop in the CO 2 atmospheric levels. Here we present high-resolution planktonic foraminifera data (mean sampling resolution of about 780 years) from core LC10 recovered in the Ionian Sea (eastern Mediterranean), between 1.2 and 0.9 Ma. Selected taxa, among them G. ruber , T. quinqueloba and G. bulloides , show significant periodicities that can be associated to orbital cycles, mainly precession and obliquity.…

Conflicting coccolithophore and geochemical evidence for productivity levels in the Eastern Mediterranean sapropel S1

2011

Abstract The cyclic development of anoxic conditions in the eastern Mediterranean deep sea waters is one of the most fascinating research topics in paleoceanographic studies. In combination with bottom water stagnation, enhanced primary production is a common explanation for the deposition of organic-rich layers (sapropels). This is supported by extensive evidence from both geochemical and micropaleontological studies. The correspondence of recent sapropel layers with peaks of the lower photic zone coccolithophore species Florisphaera profunda has been interpreted as a proxy for the development of a deep chlorophyll maximum (DCM), due to the pycnocline/nutricline shallowing into the lower p…

The Postglacial Isotopic Record of Intermediate Water Connects Mediterranean Sapropels and Organic‐Rich Layers

2020

Carbon‐rich layers exist at both sides of the Mediterranean Sea sedimentary record and are called sapropels and organic rich layers (ORLs), respectively, in the eastern and western basins. They have different levels of organic carbon accumulation and seafloor oxygen deprivation. The most recent sapropel and ORL depositions have a different timing, approximately 10.8–6.1 and 14.5–9.0 ka, respectively. Here we investigate oxygen isotopic records of three foraminifera species that occupy different habitats within the Sicily Channel water column since ~12.0 ka, thus in the sill between the eastern and western Mediterranean basins. These data are ice volume corrected, to get information on water…

Paesaggio culturale dei sistemi tradizionali: l'olivo in Italia

2005

We used a new sedimentary record to reconstruct the Holocene vegetation and fire history of Gorgo Basso, a coastal lake in south-western Sicily (Italy). Pollen and charcoal data suggest a fire-prone open grassland near the site until ca 10,000 cal yr BP (8050 cal BC), when Pistacia shrubland expanded and fire activity declined, probably in response to increased moisture availability. Evergreen Olea europaea woods expanded ca 8400 to decline abruptly at 8200 cal yr BP, when climatic conditions became drier at other sites in the Mediterranean region. Around 7000 cal yr BP evergreen broadleaved forests (Quercus ilex, Quercus suber and O. europaeo) expanded at the cost of open communities. The …

Sapropeļa izmantošana personīgās higiēnas līdzekļos: sapropeļa cieto ziepju īpašības un izmantošanas dzīves cikla novērtējums

2015

Bakalaura darba “Sapropeļa izmantošana personīgas higiēnas līdzekļos: sapropeļa cieto ziepju īpašības un izmantošanas dzīves cikla novērtējums” ietvaros tika noteikti triju tirgū pieejamo un četru paštaisīto ezeru nogulumu cieto ziepju kvalitātes rādītāji un īpašības, paštaisītām ziepēm tika modelēts izmantošanas dzīves cikls. Paštaisītās sapropeļa ziepes tika pagatavotas, izmantojot sapropeli kā pildījumu. Darba teorētiskajā daļā tika veikta zinātniskās literatūras analīze par cieto ziepju pagatavošanas metodēm, piedevu īpašībām un to sastāvu, produkta izmantošanas dzīves ciklu, kā arī par sapropeļa izmantošanu kosmetoloģijā un balneoloģijā. Bakalaura darba ietvaros pēc autores izstrādātās…

Bioogles un sapropeļa izmantošanas iespējas augsnes substrāta izveidē

2017

Bakalaura darba “Bioogles un sapropeļa izmantošanas iespējas augsnes substrāta izveidē” teorētiskajā daļā, tika veikta zinātniskās literatūras analīze par augsnes aktuālajām problēmām un iespējamajiem risinājumiem. Tika apkopota zinātniskā informācija par bioogli un sapropeli, kā arī to īpašībām. Darba gaitā tika izgatavotas augsnes substrāta granulas no bioogles un Piksteres ezera sapropeļa. Izejmateriāliem noteikts ķīmiskais sastāvs, pelnu saturs, ūdens izvilkuma pH un elektrovadītspēja. Izveidotajām granulām noteikti ķīmiskie un fiziskie parametri (ķīmiskais sastāvs, mehāniskā izturība, blīvums u.c.) Bioogles suspensijā audzējot sīpolus, tika noteikta bioogles ietekme uz augu attīstību. …