scholarly journals Rock magnetic and geochemical analyses of surface sediment characteristics in deep ocean environments: A case study across the Ryukyu Trench

2008 ◽  
Vol 60 (3) ◽  
pp. 179-189 ◽  
Author(s):  
Noriko Kawamura ◽  
Kiichiro Kawamura ◽  
Naoto Ishikawa
Keyword(s):  
Surface Sediment ◽  
Deep Ocean ◽  
Sediment Characteristics ◽  
Ryukyu Trench ◽  
Geochemical Analyses

scholarly journals The role of continental shelves in nitrogen and carbon cycling: Northwestern North Atlantic case study

Ocean Science ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 539-548 ◽  
Author(s):  
K. Fennel
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Deep Ocean ◽  
Open Ocean ◽  
Biogeochemical Models ◽  
Inorganic Matter ◽  
Continental Shelves ◽  
Shelf Region

Abstract. Continental shelves play a key role in the cycling of nitrogen and carbon. Here the physical transport and biogeochemical transformation processes affecting the fluxes into and out of continental shelf systems are reviewed, and their role in the global cycling of both elements is discussed. Uncertainties in the magnitude of organic and inorganic matter exchange between shelves and the open ocean is a major source of uncertainty in observation-based estimates of nitrogen and carbon fluxes. The shelf-open ocean exchange is hard to quantify based on observations alone, but can be inferred from biogeochemical models. Model-based nitrogen and carbon budgets are presented for the Northwestern North Atlantic continental shelf. Results indicate that shelves are an important sink for fixed nitrogen and a source of alkalinity, but are not much more efficient in exporting organic carbon to the deep ocean than the adjacent open ocean for the shelf region considered.

Depositional environments, sediment characteristics, palaeoecological analysis and environmental assessment of an internationally protected shallow Mediterranean lagoon, Gialova Lagoon – Navarino Bay, Greece

2014 ◽  
Vol 105 (3) ◽  
pp. 189-206 ◽  
Author(s):  
P. Avramidis ◽  
G. Iliopoulos ◽  
N. Kontopoulos ◽  
D. Panagiotaras ◽  
P. Barouchas ◽  
...  
Keyword(s):  
Natura 2000 ◽  
Enrichment Factors ◽  
Depositional Environments ◽  
Geochemical Characteristics ◽  
Geochemical Data ◽  
Sediment Characteristics ◽  
Protection Area ◽  
Moment Measures ◽  
Geochemical Analyses ◽  
International Conventions

ABSTRACTThis study presents sedimentological, palaeoecological and geochemical data from a shallow Mediterranean coastal lagoon which has been severely influenced by human intervention over the last 70 years. The Gialova Lagoon is protected by international conventions and is listed in the Natura 2000 European Community Network as Special Protection Area (SPA) and Site of Community Importance (SCI). The spatial variability of sediment characteristics such as grain size, total organic carbon (TOC) and moment measures, mean, sorting, kurtosis and skewness were calculated. Moreover, micro- and macrofossil and sediment geochemical analyses were carried out on six gravity core samples. Study of the above parameters indicates that the anthropogenic impact and intervention are reflected in the micro- (ostracods, foraminifera, charophytes) and macrofossil (molluscs) taxa corresponding to different depositional environmental facies, representing a brackish lagoon with the influence of (a) fresh water inflow, (b) shallow marine environment and (c) hypoxic and dystrophic conditions. The geochemical characteristics and the calculation of the degree of sediment contamination using enrichment factors (EF), contamination factors (Cif) and the index of geo-accumulation (Igeo) indicate a recent relative improvement of the lagoon towards the upper layers of the gravity cores, rendering the lagoon as unpolluted to moderately polluted. This combinatorial study of sediment geochemical characteristics, as well as the downcore micro- and macrofossil assemblages, can be considered as a baseline for future monitoring in accordance with European Union directives, and for any future engineering interventions for the lagoon environmental maintenance and conservation; as this is the first time that geochemical and downcore palaeoecological data have been presented from this lagoon.

Origins of lipid biomarkers in Santa Monica Basin surface sediment: a case study using compound-specific Δ 14 C analysis

2001 ◽  
Vol 65 (18) ◽  
pp. 3123-3137 ◽  
Author(s):  
A. Pearson ◽  
A.P. McNichol ◽  
B.C. Benitez-Nelson ◽  
J.M. Hayes ◽  
T.I. Eglinton
Keyword(s):  
Surface Sediment ◽  
Lipid Biomarkers ◽  
Basin Surface ◽  
Santa Monica ◽  
Santa Monica Basin

scholarly journals SAND BORROW AREA DESIGN REFINEMENT TO REDUCE MORPHOLOGICAL IMPACTS: A CASE STUDY OF PANAMA CITY BEACH, FLORIDA, USA.

2012 ◽  
Vol 1 (33) ◽  
pp. 103
Author(s):  
Luana Taiani ◽  
Lindino Benedet ◽  
Lucas Silveira ◽  
Stephen Keehn ◽  
Nicole Sharp ◽  
...  
Keyword(s):  
Incident Wave ◽  
Side Effect ◽  
Substantial Reduction ◽  
Depth Of Cut ◽  
Sediment Characteristics ◽  
Volume Changes ◽  
Panama City ◽  
Cut Depth ◽  
Beach Volume

The coastline of Panama City Beach, Florida (FL) has been stricken by several hurricanes during the last decades, especially after 1995. In 1998, beach nourishment projects started being implemented to address the impacts of the hurricanes on the coast. Sources of sand for that purpose are commonly from borrow areas located just offshore of the nourishment site. Impacts of these nearshore dredge pits on adjacent coasts will depend on incident wave conditions, nourishment sediment characteristics and some features of the borrow pit (distance from the shore, depth of cut, cross-shore extent, alongshore extent and orientation - Bender & Dean, 2003; Benedet & List, 2008). The practical goal of the current study was to mitigate for the negative potential effects by discovering the less impactful design of dredge pit geometries on the Borrow Area S1 in Bay County-FL. Five different cut widths and excavation depths within the permitted limits were herein evaluated. Evaluation of morphological impacts on adjacent beaches was carried with the processed-based morphodynamic model Delft3D, calibrated and simulated for a period of 13 years. Results were evaluated in terms of beach volume changes compared against a baseline simulation (no action).Switching from Alternative 1 (6,260,000 m³) to Alternative 2 (5,380,000 m³) does not result in a substantial reduction of the borrow area’s projected impact. The cut depth is still deep, and the surface area is unchanged. Alternative 3 (3,555,000 m³) is able to provide more substantial reductions in the borrow area’s impact. By reducing the acreage of the borrow area and switching to a uniform cut depth, the projected impact of the borrow area decreases 39% for 1.56 km along the downdrift beach. Under Alternatives 4 (3,060,000 m³) and 5 (2,755,000 m³), the impacts of the borrow area are projected to be less than 3.75 m³/m/yr. While both alternatives are viable, Alternative 5 minimizes potential impacts, and has a uniform cut depth and a volume that still satisfies the project’s requirements. Given these considerations, Alternative 5 is the preferred alternative. Additionally, all the alternatives increase the net-accretion along 6.5 km of Shell Island between 0.25 to 1 m³/lm/yr., a valuable side effect in a region with high net erosion. By conducting various simulations an optimal borrow area design has been identified that reduces its effects on the adjacent beaches.

scholarly journals PENELITIAN TIMAH PLASER MELALUI ANALISIS SAYATAN OLES DAN GEOKIMIA : STUDI KASUS PERAIRAN TELUK PINANG, PROVINSI RIAU

2016 ◽  
Vol 8 (2) ◽  
pp. 67
Author(s):  
Yudi Darlan ◽  
Udaya Kamiludin
Keyword(s):  
Heavy Metals ◽  
Key Words ◽  
Surface Sediment ◽  
Surface Sediments ◽  
High Density ◽  
The World ◽  
Metal Element ◽  
Tin Deposits ◽  
Geochemical Analyses ◽  
Tin Metal

Kebutuhan pasar dunia akan timah meningkat, sehingga pencarian sumberdaya timah banyak dilakukan, termasuk kawasan perairan Riau, Bangka dan Belitung. Bijih timah dalam mineral kasiterit mempunyai Berat Jenis tinggi, sehingga endapan timah alluvium akan tersebar di sekitar sumber asal timah. Analisis geokimia merupakan salah satu metoda yang digunakan untuk menjawab apakah timah dan logam lainnya dalam bentuk unsur berpotensi sebagai sumber daya. Kandungan unsur logam timah yang terdapat pada sedimen permukaan di sekitar aliran dan muara sungai kurang dari 10ppm lebih kecil dibandingkan dengan kandungan unsur logam timah yang ada pada sedimen permukaan dasar laut (20ppm – 80ppm). Kata kunci: timah plaser, analisis sayatan oles dan geokimia, sedimen permukaan, Teluk Pinang, Provinsi Riau The demand of world trades for tin is high, hence explorations for resources of tin in the world, for example Riau, Bangka, and Blitung of Indonesia waters have been carried out. Tin ores of cassiterite has high density, therefore alluvial tin deposits will distributes near their resources. Geochemical analyses is one of the methods which is applied to explain that are tin and heavy metals deposits are prospect at the study area. This is as a main aim of research at Teluk Pinang waters and adjacent areas. The content of tin metal element contained in surface sediments in the river streams and rmouth less than 10ppm is smaller than the content of tin metal element exist on the seafloor surface sediment (20ppm - 80ppm). Key words: placer tin, smear slides and geochemistry analyses, surfacial sediment, The Pinang Bay, Riau Province

Sign in / Sign up

Export Citation Format

Share Document