scholarly journals Holocene buried organic sediments in Estonia

2006 ◽  
Vol 55 (4) ◽  
pp. 296
Author(s):  
A Miidel ◽  
E Niinemets ◽  
L Saarse ◽  
J Vassiljev
Keyword(s):  
Organic Sediments

Stabilizing pyritic material

1989 ◽  
Vol 4 ◽  
pp. 244-248 ◽  
Author(s):  
Donald L. Wolberg
Keyword(s):  
Significant Contribution ◽  
Organic Materials ◽  
Sedimentary Rocks ◽  
Iron Sulfides ◽  
Decomposition Products ◽  
Iron Minerals ◽  
Pyrite Formation ◽  
Organic Sediments ◽  
Freshwater Environments

The minerals pyrite and marcasite (broadly termed pyritic minerals) are iron sulfides that are common if not ubiquitous in sedimentary rocks, especially in association with organic materials (Berner, 1970). In most marine sedimentary associations, pyrite and marcasite are associated with organic sediments rich in dissolved sulfate and iron minerals. Because of the rapid consumption of sulfate in freshwater environments, however, pyrite formation is more restricted in nonmarine sediments (Berner, 1983). The origin of the sulfur in nonmarine environments must lie within pre-existing rocks or volcanic detritus; a relatively small, but significant contribution may derive from plant and animal decomposition products.

Organic Sediments in River Beds

Ground Water ◽  
1963 ◽  
Vol 1 (3) ◽  
pp. 12-12
Author(s):  
William V. Karr
Keyword(s):  
Organic Sediments

scholarly journals Intestinal parasite analysis in organic sediments collected from a 16th-century Belgian archeological site

2005 ◽  
Vol 21 (1) ◽  
pp. 329-332 ◽  
Author(s):  
Alexandre Fernandes ◽  
Luiz Fernando Ferreira ◽  
Marcelo Luiz Carvalho Gonçalves ◽  
Françoise Bouchet ◽  
Carlos Henrique Klein ◽  
...  
Keyword(s):  
Intestinal Parasite ◽  
Parasite Burden ◽  
Northern Coast ◽  
Free Living ◽  
High Infection ◽  
Free Living Nematode ◽  
Organic Sediments ◽  
The Village ◽  
Archeological Site ◽  
Organic Remains

Parasite eggs found in organic remains collected from medieval structures in Raversijde (medieval name: Walraversijde), a village on the northern coast of Belgium, are discussed. The eggs were identified as Ascaris lumbricoides and Trichuris trichiura, both human parasites. Species identification allowed elucidating the origin of the organic sediments and the structures, in this case latrines used by humans. Capillaria sp. and free-living nematode larvae were also found in the latrine. Although neither parasite burden nor prevalence rates could be measured, the abundance of human intestinal parasite eggs indicated a high infection rate in the village residents, reflecting very poor sanitation.

scholarly journals Identification of a population of Ranunculus achenes extracted from Middle Pleistocene sediments exposed at Belhus Park, Essex, UK

2013 ◽  
Vol 53 (2) ◽  
pp. 181-189
Author(s):  
Michael H. Field
Keyword(s):  
Morphological Characteristics ◽  
Middle Pleistocene ◽  
Fluvial Sediments ◽  
Flowing Water ◽  
Dry Grassland ◽  
River Catchment ◽  
Plant Macrofossil ◽  
Organic Sediments

ABSTRACT A plant macrofossil assemblage extracted from Middle Pleistocene fluvial organic sediments collected from Belhus Park, Aveley, Essex, UK contained a number of tuberculate (verrucose) achenes attributed to the genus Ranunculus, one of which had two short spines preserved on its surface. The identification of these achenes is discussed here. This is worthy of note because Ranunculus tuberculate or spinose fossil achenes can be difficult to determine to species as they can have similar features, some Ranunculus species produce achenes in several morphological forms, and during fossilization delicate structures maybe destroyed (e.g. spines). After careful morphological consideration it is concluded that the fossil achenes from Belhus Park are Ranunculus parviflorus L., indicating that dry grassland or disturbed ground existed in the river catchment. The plant macrofossil assemblages that included the Ranunculus parviflorus achenes were dominated by waterside, damp ground, and aquatic taxa. It is probable that flowing water transported the achenes from further afield before their incorporation into the fluvial sediments. The identification of these fossils illustrates the importance of considering the morphological characteristics of the achene only and not to make a determination on the nature of the predominant palaeoenvironmental signal from an assemblage.

scholarly journals Disturbances Of The Holocene Lake-Bog Sediment Succession As Revealed By Pollen Record From Wietrzychowice (Southeastern Kujawy, Central Poland)

2015 ◽  
Vol 32 (2) ◽  
pp. 91-97
Author(s):  
Eva Břízová ◽  
Małgorzata Roman
Keyword(s):  
Middle Ages ◽  
Pollen Analysis ◽  
Pollen Record ◽  
Sediment Characteristics ◽  
Pollen Data ◽  
The Holocene ◽  
The Third ◽  
Late Middle Ages ◽  
Organic Sediments ◽  
Funnel Beaker Culture

Abstract Results of geological and pollen investigations of the lake-bog sediments from the section Wietrzychowice W5, located nearby the Neolithic Funnel Beaker Culture (FBC) megaliths, are presented. The pollen data reveal that sedimentation at Wietrzychowice has begun at the beginning of the Holocene (Preboreal). Pollen analysis was used to determine stratigraphy with regard to sediment characteristics. The pollen spectrum was divided into 8 LPAZes (1-7Xa, 7Xb) which were also, where possible, stratigraphically classified. Radiocarbon dating of 6 730 ± 90 BP (5 730–5 480 BC, MKL-702) at depth of 1.20 m confirmed the pollen analysis age estimation. Five settlement episodes were found in organic sediments in the upper part of the W5 core. The first was presumably during the Preboreal, the second in the early Atlantic, the third in the late Atlantic (probably Neolithic FBC), the fourth in the early Middle Ages and the last one in the late Middle Ages. The pollen analysis was useful to point irregularities in sediment succession. Such a situation made palaeoenvironmental interpretation difficult, but further research is still needed to enable an accurate reconstruction.

scholarly journals Thresholds of mangrove survival under rapid sea level rise

Science ◽  
2020 ◽  
Vol 368 (6495) ◽  
pp. 1118-1121 ◽  
Author(s):  
N. Saintilan ◽  
N. S. Khan ◽  
E. Ashe ◽  
J. J. Kelleway ◽  
K. Rogers ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Carbon Sink ◽  
Vertical Accretion ◽  
Mangrove Forests ◽  
Relative Sea Level ◽  
Relative Sea Level Rise ◽  
Emissions Scenarios ◽  
Organic Sediments ◽  
Timing Of Initiation

The response of mangroves to high rates of relative sea level rise (RSLR) is poorly understood. We explore the limits of mangrove vertical accretion to sustained periods of RSLR in the final stages of deglaciation. The timing of initiation and rate of mangrove vertical accretion were compared with independently modeled rates of RSLR for 78 locations. Mangrove forests expanded between 9800 and 7500 years ago, vertically accreting thick sequences of organic sediments at a rate principally driven by the rate of RSLR, representing an important carbon sink. We found it very likely (>90% probability) that mangroves were unable to initiate sustained accretion when RSLR rates exceeded 6.1 millimeters per year. This threshold is likely to be surpassed on tropical coastlines within 30 years under high-emissions scenarios.

Influence of Sediment on Anthracene Uptake, Depuration, and Biotransformation by the Amphipod Hyalella azteca

1983 ◽  
Vol 40 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Peter F. Landrum ◽  
Donald Scavia
Keyword(s):  
Rate Constant ◽  
Body Burden ◽  
Water Concentration ◽  
Hyalella Azteca ◽  
Benthic Organisms ◽  
Organic Sediment ◽  
Wet Weight ◽  
The Mean ◽  
Organic Sediments ◽  
State Body

Uptake, depuration, and biotransformation rates of anthracene were determined for Hyalella azteca (Amphipoda, Crustacea) in both the presence and the absence of sediment. The mean rate constant ± SE for uptake from water was the same for cases with or without sediment, 255 ± 76 mL∙(g animal wet weight)−1∙h−1. The rate constant for uptake of sediment-associated anthracene was 19 ± 5 g dry sediment∙(g animal wet weight)−1∙h−1 for an organic sediment. Depuration increased by a factor of three in the presence of sediment. Sediment-associated anthracene, compound sorbed to sediment and in pore water, was estimated to contribute 77% of the steady-state body burden. These animals, and presumably other benthic organisms exposed to toxicants in organic sediments, are at higher risk than animals not associated with sediments. Further, bioconcentration factors based on the ratio of body burden to water concentration are overestimates for H. azteca and other benthic organisms that obtain a large proportion of their body burden from sediment.Key words: anthracene, Hyalella azteca, sediment, PAH

Sign in / Sign up

Export Citation Format

Share Document