scholarly journals Laminae type and possible mechanisms for the formation of laminated sediments in the Shaban Deep, northern Red Sea

2005 ◽  
Vol 2 (4) ◽  
pp. 331-362
Author(s):  
I. A. Seeberg-Elverfeldt ◽  
C. B. Lange ◽  
J. Pätzold ◽  
G. Kuhn
Keyword(s):  
Water Column ◽  
Red Sea ◽  
Water Depth ◽  
Laminated Sediments ◽  
Gravity Core ◽  
Fecal Pellets ◽  
Laminated Structure ◽  
Pyrite Formation ◽  
Backscattered Electron ◽  
Northern Red Sea

Abstract. Laminated sediments in the Shaban Deep, a brine-filled basin in the northern Red Sea, were analyzed with backscattered electron imagery. Here we present possible mechanisms involved in the formation of laminae of various types and homogenous intervals arising from the detailed investigation of multicore GeoB 7805-1 (26 13.9' N and 35 22.6' E; water depth 1447 m) and gravity core GeoB 5836-2 (26 12.61' N, 35 21.56' E; water depth 1475 m). Sediment makeup includes six types: a) a laminated structure with alternating light (mainly coccoliths) and dark (diatom frustules) layers, where the diatom component is indicative of the intra-annual variability between stratification and mixing events; b) a pocket-like structure attributed to the sinking of particles within fecal pellets and aggregates; c) a matrix of tightly packed diatoms that relates to extended stratification/mixing periods of the water column; d) homogenous intervals that result from turbidity deposition; e) silt accumulations which origin may lie in agglutinated foraminifers; and f) pyrite layers with pyrite formation initiated at the seawater-brine interface.

scholarly journals Laminae type and possible mechanisms for the formation of laminated sediments in the Shaban Deep, northern Red Sea

Ocean Science ◽  
2005 ◽  
Vol 1 (2) ◽  
pp. 113-126 ◽  
Author(s):  
I. A. Seeberg-Elverfeldt ◽  
C. B. Lange ◽  
J. Pätzold ◽  
G. Kuhn
Keyword(s):  
Water Column ◽  
Red Sea ◽  
Water Depth ◽  
Laminated Sediments ◽  
Gravity Core ◽  
Fecal Pellets ◽  
Laminated Structure ◽  
Pyrite Formation ◽  
Backscattered Electron ◽  
Northern Red Sea

Abstract. Laminated sediments in the Shaban Deep, a brine-filled basin in the northern Red Sea, were analyzed with backscattered electron imagery. Here we present possible mechanisms involved in the formation of laminae of various types and homogenous intervals arising from the detailed investigation of multicore GeoB 7805-1 (26°13.9' N and 35°22.6' E; water depth 1447 m) and gravity core GeoB 5836-2 (26°12.61' N, 35°21.56' E; water depth 1475 m). Sediment makeup includes six types: a) a laminated structure with alternating light (mainly coccoliths) and dark (diatom frustules) layers, where the diatom component is indicative of the intra-annual variability between stratification and mixing events; b) a pocket-like structure attributed to the sinking of particles within fecal pellets and aggregates; c) a matrix of tightly packed diatoms that relates to extended stratification/mixing periods of the water column; d) homogenous intervals that result from turbidity deposition; e) silt accumulations which origin may lie in agglutinated foraminifers; and f) pyrite layers with pyrite formation initiated at the seawater-brine interface.

A Pronounced Dry Event Recorded Around 4.2 ka in Brine Sediments from the Northern Red Sea

2006 ◽  
Vol 66 (3) ◽  
pp. 432-441 ◽  
Author(s):  
Helge W. Arz ◽  
Frank Lamy ◽  
Jürgen Pätzold
Keyword(s):  
Red Sea ◽  
Environmental Changes ◽  
Laminated Sediments ◽  
Drought Event ◽  
Stable Oxygen Isotopes ◽  
Deep Basin ◽  
Salinity Anomaly ◽  
Surface Dwelling ◽  
Stable Oxygen ◽  
Northern Red Sea

AbstractPartly laminated sediments were sampled from the brine-filled, anoxic Shaban Deep basin in the northern Red Sea. At about 4200 cal yr BP more than two millennia of anoxic sedimentation is replaced by a sub-oxic facies strongly suggesting the episodic absence of the brine. At the same time stable oxygen isotopes from surface dwelling foraminifera show a sharp increase (within less than 100 yr) pointing to a strong positive salinity anomaly at the sea surface. This major evaporation event significantly enhanced the renewal of deep water and the subsequent ventilation of the small Shaban Deep basin. The timing and strength of the reconstructed environmental changes around 4200 cal yr BP suggest that this event is the regional expression of a major drought event, which is widely observed in the neighboring regions, and which strongly affected Middle East agricultural civilizations.

The significance of diatoms in the formation of laminated sediments of the Shaban Deep, Northern Red Sea

2004 ◽  
Vol 209 (1-4) ◽  
pp. 279-301 ◽  
Author(s):  
Ismene A. Seeberg-Elverfeldt ◽  
Carina B. Lange ◽  
Helge W. Arz ◽  
Jürgen Pätzold ◽  
Jennifer Pike
Keyword(s):  
Red Sea ◽  
Laminated Sediments ◽  
Northern Red Sea

Comparison of the performance of oscillating water column devices based on arrangements of water columns

2020 ◽  
Vol 14 (3) ◽  
pp. 7082-7093
Author(s):  
Jahirwan Ut Jasron ◽  
Sudjito Soeparmani ◽  
Lilis Yuliati ◽  
Djarot B. Darmadi
Keyword(s):  
Wave Propagation ◽  
Water Column ◽  
Water Depth ◽  
Graphical Form ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Power Absorption ◽  
Water Columns ◽  
Single Column ◽  
Parallel Arrangement

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

scholarly journals Tidal variability of nutrients in a coastal coral reef system influenced by groundwater

2018 ◽  
Vol 15 (4) ◽  
pp. 997-1009 ◽  
Author(s):  
Guizhi Wang ◽  
Shuling Wang ◽  
Zhangyong Wang ◽  
Wenping Jing ◽  
Yi Xu ◽  
...  
Keyword(s):  
Coral Reef ◽  
Water Column ◽  
Water Depth ◽  
Neap Tide ◽  
Groundwater Discharge ◽  
Spring Tide ◽  
Biological Processes ◽  
Reef System ◽  
Nitrite Nitrate ◽  
Coral Reef System

Abstract. To investigate variation in nitrite, nitrate, phosphate, and silicate in a spring–neap tide in a coral reef system influenced by groundwater discharge, we carried out a time-series observation of these nutrients and 228Ra, a tracer of groundwater discharge, in the Luhuitou fringing reef at Sanya Bay in the South China Sea. The maximum 228Ra, 45.3 dpm 100 L−1, appeared at low tide and the minimum, 14.0 dpm 100 L−1, appeared during a flood tide in the spring tide. The activity of 228Ra was significantly correlated with water depth and salinity in the spring–neap tide, reflecting the tidal-pumping feature of groundwater discharge. Concentrations of all nutrients exhibited strong diurnal variation, with a maximum in the amplitude of the diel change for nitrite, nitrate, phosphate, and silicate in the spring tide of 0.46, 1.54, 0.12, and 2.68 µM, respectively. Nitrate and phosphate were negatively correlated with water depth during the spring tide but showed no correlation during the neap tide. Nitrite was positively correlated with water depth in the spring and neap tide due to mixing of nitrite-depleted groundwater and nitrite-rich offshore seawater. They were also significantly correlated with salinity (R2  ≥  0.9 and P < 0.05) at the ebb flow of the spring tide, negative for nitrate and phosphate and positive for nitrite, indicating the mixing of nitrite-depleted, nitrate- and phosphate-rich less saline groundwater and nitrite-rich, nitrate- and phosphate-depleted saline offshore seawater. We quantified variation in oxidized nitrogen (NOx) and phosphate contributed by biological processes based on deviations from mixing lines of these nutrients. During both the spring and neap tide biologically contributed NOx and phosphate were significantly correlated with regression slopes of 4.60 (R2  =  0.16) in the spring tide and 13.4 (R2  =  0.75) in the neap tide, similar to the composition of these nutrients in the water column, 5.43 (R2  =  0.27) and 14.2 (R2  =  0.76), respectively. This similarity indicates that the composition of nutrients in the water column of the reef system was closely related with biological processes during both tidal periods, but the biological influence appeared to be less dominant, as inferred from the less significant correlations (R2  =  0.16) during the spring tide when groundwater discharge was more prominent. Thus, the variability of nutrients in the coral reef system was regulated mainly by biological uptake and release in a spring–neap tide and impacted by mixing of tidally driven groundwater and offshore seawater during spring tide.

Iron and sulphur speciation and cycling in the sediments of marine systems located in the arid environment: Case of the northern Red Sea

2021 ◽  
pp. jgs2021-027
Author(s):  
Valeria Boyko ◽  
Jürgen Pätzold ◽  
Alexey Kamyshny
Keyword(s):  
Red Sea ◽  
Water Depth ◽  
Iron Content ◽  
Gulf Of Aqaba ◽  
Earth System ◽  
Content Type ◽  
Reactive Iron ◽  
The Earth ◽  
Sulphur Cycle ◽  
Supplementary Material

High fluxes of iron minerals associated with aeolian dry deposition may result in anomalously high reactive iron content and fast reoxidation of hydrogen sulphide in the sediments that prevents pyrite formation and results in “cryptic” sulphur cycle. In this work, we studied cycling of iron and sulphur in the deep-water (> 800 m water depth) sediments of the Red Sea and its northern extension, Gulf of Aqaba. We found that reactive iron content in the surface sediments of the Gulf of Aqaba and the Red Sea is high, while the content of sulphur-bound iron is very low and decreases with water depth. The presence of pyrite traces and zero-valent sulfur as well as isotopic compositions of sulphate and pyrite, which are consistent with sulphate reduction under substrate-limiting conditions, suggest that cryptic sulfur cycling is likely to be a result of fast reoxidation of hydrogen sulfide rather than microbial sulfate reduction suppression. In the sediments of Shaban Deep, which are overlain with hyper-saline hydrothermal brine, low reactive iron and high organic carbon contents result in a non-cryptic sulphur cycle characterized by preservation of pyrite in the sediments.Thematic collection: This article is part of the Sulfur in the Earth system collection available at: https://www.lyellcollection.org/cc/sulfur-in-the-earth-systemSupplementary material:https://doi.org/10.6084/m9.figshare.c.5508155

scholarly journals Wave power extraction from a bottom-mounted oscillating water column converter with a V-shaped channel

2014 ◽  
Vol 470 (2167) ◽  
pp. 20140074 ◽  
Author(s):  
Zhengzhi Deng ◽  
Zhenhua Huang ◽  
Adrian W. K. Law
Keyword(s):  
Water Column ◽  
Water Depth ◽  
Wave Energy ◽  
High Efficiency ◽  
Expansion Method ◽  
Opening Angle ◽  
Energy Extraction ◽  
Oscillating Water Column ◽  
Wave Direction ◽  
Power Extraction

An analytical theory is developed for an oscillating water column (OWC) with a V-shaped channel to improve the pneumatic efficiency of wave energy extraction. An eigenfunction expansion method is used in a cylindrical coordinate system to investigate wave interaction with the OWC converter system. Auxiliary functions are introduced to capture the singular behaviours in the velocity field near the salient corners and cusped edges. Effects of the OWC dimensions, the opening angle and length of the V-shaped channel, as well as the incident wave direction, on the pneumatic efficiency of wave energy extraction are examined. Compared with a system without the V-shaped channel, our results show that the V-shaped channel can significantly increase the conversion efficiency and widen the range of wave frequency over which the OWC system can operate at a high efficiency. For typical coastal water depths, the OWC converter system can perform efficiently when the diameter of the OWC chamber is in the range of 1 5 – 1 2 times the water depth, the opening angle of the V-shaped channel is in the range of [ π /2, 3 π /4] and the length of the V-shaped channel is in the range of 1–1.5 times the water depth.

Sign in / Sign up

Export Citation Format

Share Document