Systems supplying sediment to canyon heads (SSSCHs) in the Tyrrhenian Sea: The past and the present as a key to understanding deep-sea stratigraphy

2020 ◽  
Vol 119 ◽  
pp. 104470
Author(s):  
Fabiano Gamberi
Keyword(s):  
Deep Sea ◽  
Tyrrhenian Sea ◽  
The Past

Quaternary Hypsithermals

1972 ◽  
Vol 2 (3) ◽  
pp. 270-273 ◽  
Author(s):  
Cesare Emiliani
Keyword(s):  
High Temperature ◽  
Deep Sea ◽  
Isotopic Analysis ◽  
The Past ◽  
Absolute Dating ◽  
Oxygen Isotopic ◽  
Environmental Balance ◽  
Past Half ◽  
Oxygen Isotopic Analysis

Oxygen isotopic analysis and absolute dating of deep-sea cores show that temperatures as high as those of today occurred for only about 10% of the time during the past half million years. The shortness of the high temperature intervals (“hypsithermals”) suggests a precarious environmental balance, a condition which makes man's interference with the environment during the present hypsithermal extremely critical. This precarious balance must be stabilized if a new glaciation or total deglaciation is to be avoided.

A Ballast System for Automated Deep-Sea Ascents

2016 ◽  
Author(s):  
Matthias Golz ◽  
Florin Boeck ◽  
Sebastian Ritz ◽  
Gerd Holbach
Keyword(s):  
Environmental Impact ◽  
Environmental Contamination ◽  
Pressure Vessel ◽  
Deep Sea ◽  
Underwater Vehicles ◽  
Compressed Air ◽  
Hydraulic Pump ◽  
Unmanned Underwater Vehicles ◽  
The Past ◽  
Set Up

The efforts to discover the world’s oceans — even in extremely deep-sea environments — have grown more and more in the past years. In this context, unmanned underwater vehicles play a central role. Underwater systems that are not tethered need to provide an apparatus to ensure a safe return to the surface. Therefore, positive buoyancy is required and can be achieved by either losing weight or expanding volume. A conservative method is the dropping of ballast weight. However, nowadays this method is not appropriate due to the environmental impact. This paper presents a ballast system for an automated ascent of a deep-sea seabed station in up to 6000 m depth. The ballast system uses a DC motor driven modified hydraulic pump and a compressed air auxiliary system inside a pressure vessel. With regard to the environmental contamination in case of a leakage, only water is used as ballast fluid. The modification of an ordinary oil-hydraulic radial piston pump and the set-up of the ballast system is introduced. Results from sea trials in the Atlantic Ocean are presented to verify the functionality of the ballast system.

Seasonal deposition of phytodetritus to the deep-sea floor

1986 ◽  
Vol 88 ◽  
pp. 265-279 ◽  
Author(s):  
A. L. Rice ◽  
D. S. M. Billett ◽  
J. Fry ◽  
A. W. G. John ◽  
R. S. Lampitt ◽  
...  
Keyword(s):  
Deep Sea ◽  
Benthic Communities ◽  
Time Lapse ◽  
Sediment Traps ◽  
Temporal Variations ◽  
Sea Floor ◽  
Porcupine Seabight ◽  
The Past ◽  
Sea Bed ◽  
Seasonal Deposition

SynopsisEvidence has accumulated over the past twenty years to suggest that the deep-sea environment is not as constant as was at one time thought, but exhibits temporal variations related to the seasonally in the overlying surface waters. Recent results from deep-moored sediment traps suggest that this coupling is mediated through the sedimentation of organic material, while observations in the Porcupine Seabight indicate that in this region, at least, there is a major and rapid seasonal deposition of aggregated phytodetritus to the sea-floor at slope and abyssal depths.This paper summarises the results of the Porcupine Seabight studies over the past five years or so, using time-lapse sea-bed photography and microscopic, microbiological and chemical analyses of samples of phytodetritus and of the underlying sediment. The data are to some extent equivocal, but they suggest that the seasonal deposition is a regular and dramatic phenomenon and that the material undergoes relatively little degradation during its passage through the water column. The mechanisms leading to the aggregation of the phytodetritus have not been identified, and it is not yet known whether the phenomenon is geographically widespread nor whether it is of significance to the deep-living mid-water and benthic communities.

The work of the Discovery Committee

1950 ◽  
Vol 202 (1068) ◽  
pp. 1-16 ◽  
Keyword(s):  
Southern Ocean ◽  
Deep Water ◽  
Deep Sea ◽  
Original Form ◽  
The Past ◽  
Scientific Staff ◽  
Form Part ◽  
Whaling Industry ◽  
Major Industry ◽  
Colonial Office

The geographical field in which most of the Discovery Committee’s work has been carried out during the past 25 years is the Southern Ocean. This zone of continuous deep water, very rich in marine fife, supports one major industry—the whaling industry—but is otherwise little developed as yet, and seldom visited. It is not easy to find a short descriptive label for the work itself, but nearly all of it comes under the headings of deep-sea oceanography, whales and whaling, or Antarctic geography, and much of it is concerned with the interrelations of these subjects. Since the beginning in 1924 the Discovery Committee has worked under the Colonial Office, but in 1949 the Committee’s functions, together with the scientific staff, the ships, and other assets, were taken over by the Admiralty, and now form part of the new National Institute of Oceanography. The Discovery Committee, in its original form, has been dissolved, but it is encouraging to know that the continuation of its work is assured.

A Legacy of Zeal and Perseverance

2021 ◽  
pp. 223-259
Author(s):  
Clive Gamble
Keyword(s):  
Climate Change ◽  
Deep Sea ◽  
Modern Synthesis ◽  
Human Origins ◽  
The Past ◽  
Better Than

What happened to the surviving time revolutionaries and their legacy? Knighthoods, high office, a peerage, and bespoke mansions all followed. France preserved Boucher de Perthes’s legacy better than England that of its time revolutionaries, whom it forgot. War, however, destroyed Abbeville in 1940 and with it Boucher de Perthes’s collections and public statue. Lubbock was the last to die in 1913, having seen the Piltdown forgery. Then follows an excursion into the development of the modern synthesis of human origins with scientific dates, a detailed deep-sea record of climate change and the ages of the sites they found on the Somme and at Hoxne. Changing views of our remote ancestors are shown in artists’ imaginings and through bestselling authors. The reticence of Prestwich and Evans to speculate was forgotten as deep history was fleshed out to resonate with the present. The chapter ends by placing the time revolution at the start of an interest in universal and deep history. The time revolutionaries changed our relationship with time and set in motion a dialogue with the past that continues to challenge and enthral.

Climate and Holocene culture change: some practical problems

1990 ◽  
Vol 330 (1615) ◽  
pp. 657-663 ◽  
Keyword(s):  
Deep Sea ◽  
Archaeological Survey ◽  
Climatic Parameters ◽  
Human Settlement ◽  
Temperature Variations ◽  
Survey Techniques ◽  
The Past ◽  
Oxygen Isotope Ratios ◽  
Agricultural Revolution ◽  
Specific Species

In recent years, not least through tree-ring studies for the Holocene and studies of oxygen isotope ratios in Foramenifera in deep-sea cores for the Pleistocene, both linked with radioactive chronometry, useful and well-dated information has become available for global temperature variations. Yet we seem at present little closer to understanding the climatic influences upon human settlement, or upon such major episodes in human existence as the agricultural revolution or the emergence of pastoral economies. In making reference to the developments in archaeological survey techniques over the past 20 years, and the increasing collaboration with geomorphologists and settlement geographers, I seek to highlight the gap in the chain of argument between data for global climatic parameters and impact on human communities. Where are the phytologists, the ecologists, the crop plant geographers? Where is the necessary focus upon the crucial themes of changing microclimates and changing agricultural productivity for specific species? An attempt is made to define more closely this deficiency.

scholarly journals AMS Radiocarbon Dates on Foraminifera from Deep Sea Sediments

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 424-428 ◽  
Author(s):  
Michael Andree ◽  
Hans Oeschger ◽  
W S Broecker ◽  
Nancy Beavan ◽  
Alan Mix ◽  
...  
Keyword(s):  
Deep Sea ◽  
East Pacific Rise ◽  
Ventilation Rate ◽  
Age Difference ◽  
Radiocarbon Dates ◽  
The Past ◽  
East Pacific ◽  
Multiple Analysis ◽  
Planktonic Species ◽  
The Tropical Pacific

14C ages were determined on samples of foraminifera separated from cores from three areas of the tropical Pacific (East Pacific Rise, Oontong Java Plateau, and South China Sea). Analyses were made on four planktonic species and on mixed benthics. The purpose of the multiple analysis on planktonic species is to assess the importance of artifacts resulting from the bioturbation-abundance change couple, from the bioturbation-partial dissolution couple and from redeposition by bottom currents. The goal is to use the benthic-planktonic age difference as a means of establishing changes in deep sea ventilation rate over the past 25,000 years. Results of a part of this work are presented in this paper.

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