scholarly journals WAVE DECAYING DUE TO BREAKING

1966 ◽  
Vol 1 (10) ◽  
pp. 15 ◽  
Author(s):  
Makoto Nakamura ◽  
Hidehiko Shiraishi ◽  
Yasuo Sasaki
Keyword(s):  
Shallow Water ◽  
Deep Sea ◽  
River Mouth ◽  
Beach Erosion ◽  
Breaking Point ◽  
Wave Transformation ◽  
Effective Measure ◽  
Planning And Design ◽  
Sea Bottom ◽  
Sea Area

In the planning and design of coastal engineering works for the control of beach characteristics, a proper and effective measure against wave must be the most important problem to be solved. When the wave generated on the open sea approaches the shallow sea area, it will be transformed under the influence of sea bottom. For the construction works of coastal structures on a shoreline or in shallow water, the estimation of the rate of wave transformation is needed. In this concern, many reports were already published by the researchers,i. e, R.L.Wiegel, M.A.Mason,H.W. Iversen and T.Kishi. Moreover, the so-called Breaker Index which shows the breaking conditions has been obtained by the Beach Erosion Bord (U.S.A.), based on the data of field observations. Furthermore, these characteristics were investigated theoretically and experimentally by H.W. Iversen, Hamada, Sato and Kishi. Though these results show the wave transformation from the deep sea to a breaking point, there are few reports dealing with the wave transformation in the process of breaking and after a breaker zone. In the execution of coastal works projected in Ministry of Agriculture and Forestry such as shore reclamation works, coastal defence works and river mouth improvement, the wave inshore from a breaker zone often should be taken into consideration. In the past design of coastal structure, the wave acting on structures in the shallow water is calculated from the deep sea wave usually by using very rough estimation that wave height is reduced by about 30 per cent after a single breaking and wave period by about 10 per cent. Consequently, in order to analyze the wave decaying due to breaking, this paper treated with the wave transformation in the vicinity of a breaking point.

scholarly journals BEHAVIOR OF FISH REEF BLOCKS FALLING THROUGH WATER

2012 ◽  
Vol 1 (33) ◽  
pp. 38
Author(s):  
Jun Mitsui ◽  
Shin-ichi Ogata ◽  
Sanae Shibata ◽  
Akira Matsumoto ◽  
Masato Yamamoto
Keyword(s):  
Deep Sea ◽  
Hydrodynamic Force ◽  
Estimation Method ◽  
Free Fall ◽  
Sufficient Accuracy ◽  
Placement Method ◽  
Sea Bottom ◽  
Concrete Blocks ◽  
Short Time ◽  
Sea Area

An accurate and economical placement method for fish reef blocks utilizing free fall in the deep sea area is presented in this paper. Falling behavior of concrete blocks in water was investigated by hydraulic model experiments and 3-D numerical computations. As a result, a new fish reef block which falls through water with highly stable behavior was developed. The distribution range of the developed block on the sea bottom was predicted by a stochastic model and it was proved to be sufficiently narrow. In addition, a quick estimation method for the placement position was developed to determine the release point of the block in actual construction. By using hydrodynamic force coefficients to evaluate the forces acting on the block, the method can estimate the falling behavior of the block in a flow field with sufficient accuracy and in a short time.

Gametogenesis and the reproductive cycle in the deep-sea anemone Paracalliactis stephensoni (Cnidaria: Actiniaria)

1990 ◽  
Vol 70 (1) ◽  
pp. 163-172 ◽  
Author(s):  
Michel Praet-Van
Keyword(s):  
Organic Matter ◽  
Shallow Water ◽  
Deep Sea ◽  
Phytoplankton Bloom ◽  
Sea Anemone ◽  
Bay Of Biscay ◽  
Sea Anemones ◽  
Spring Phytoplankton Bloom ◽  
Sea Floor ◽  
Ultrastructural Investigation

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.

scholarly journals Dispersal and Differentiation of Deep-Sea Mussels of the GenusBathymodiolus(Mytilidae, Bathymodiolinae)

2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Akiko Kyuno ◽  
Mifue Shintaku ◽  
Yuko Fujita ◽  
Hiroto Matsumoto ◽  
Motoo Utsumi ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Shallow Water ◽  
Deep Sea ◽  
Dispersal Ability ◽  
Evolutionary Transition ◽  
Significant Genetic Differentiation ◽  
Evolutionary Processes ◽  
High Dispersal ◽  
High Gene

We sequenced the mitochondrial ND4 gene to elucidate the evolutionary processes ofBathymodiolusmussels and mytilid relatives. Mussels of the subfamily Bathymodiolinae from vents and seeps belonged to 3 groups and mytilid relatives from sunken wood and whale carcasses assumed the outgroup positions to bathymodioline mussels. Shallow water mytilid mussels were positioned more distantly relative to the vent/seep mussels, indicating an evolutionary transition from shallow to deep sea via sunken wood and whale carcasses.Bathymodiolus platifronsis distributed in the seeps and vents, which are approximately 1500 km away. There was no significant genetic differentiation between the populations. There existed high gene flow betweenB. septemdierumandB. breviorand low but not negligible gene flow betweenB. marisindicusandB. septemdierumorB. brevior, although their habitats are 5000–10 000 km away. These indicate a high adaptability to the abyssal environments and a high dispersal ability ofBathymodiolusmussels.

V.—Manganese in the Sea

1876 ◽  
Vol 1 (2) ◽  
pp. 50-53 ◽  
Author(s):  
A. H. Church
Keyword(s):  
Chemical Analysis ◽  
Deep Sea ◽  
The Other ◽  
Manganese Nodules ◽  
Red Clay ◽  
Chemical Examination ◽  
Sea Bottom ◽  
Ample Supply

To the geologist, the mineralogist and the chemist, two of the observations made during the voyage of the Challenger are of especial interest. One of these observations is the occurrence over vast areas of the deep sea bottom of a peculiar red clay, containing silica, peroxide of iron, and alumina. The other discovery to which I refer has been described by Sir Wyville Thomson as the occurrence throughout this red clay of nodules of “nearly pure peroxide of manganese.” To these nodules, as well us to the red clay, an organic origin has been assigned. But the immediate source of so much manganese is hard to find, for this element is by no means an abundant constituent of animal or vegetable organisms. The difficulty is, however, somewhat lessened when the manganese nodules are submitted to a more minute chemical examination. From two correspondents I have received an ample supply of these curious concretions, accompanied by a suggestion that they should be submitted to chemical analysis.

scholarly journals The lantern shark's light switch: turning shallow water crypsis into midwater camouflage

2010 ◽  
Vol 6 (5) ◽  
pp. 685-687 ◽  
Author(s):  
Julien M. Claes ◽  
Jérôme Mallefet
Keyword(s):  
Shallow Water ◽  
Deep Sea ◽  
Light Emission ◽  
Colour Change ◽  
Hormonal Control ◽  
Nervous Control ◽  
Luminous Bacteria ◽  
Physiological Colour Change ◽  
Physiological Suppression

Bioluminescence is a common feature in the permanent darkness of the deep-sea. In fishes, light is emitted by organs containing either photogenic cells (intrinsic photophores), which are under direct nervous control, or symbiotic luminous bacteria (symbiotic photophores), whose light is controlled by secondary means such as mechanical occlusion or physiological suppression. The intrinsic photophores of the lantern shark Etmopterus spinax were recently shown as an exception to this rule since they appear to be under hormonal control. Here, we show that hormones operate what amounts to a unique light switch, by acting on a chromatophore iris, which regulates light emission by pigment translocation. This result strongly suggests that this shark's luminescence control originates from the mechanism for physiological colour change found in shallow water sharks that also involves hormonally controlled chromatophores: the lantern shark would have turned the initial shallow water crypsis mechanism into a midwater luminous camouflage, more efficient in the deep-sea environment.

Acoustic Wave Analysis In Deep Sea And Shallow Water Using Bellhop Tool

2021 ◽  
Author(s):  
Durr E Shehwar ◽  
Sana Gul ◽  
Muhammad Usama Zafar ◽  
Urooj Shaukat ◽  
Ali Hassan Syed ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Shallow Water ◽  
Deep Sea ◽  
Wave Analysis

Deep‐sea squat lobster biogeography (Munidopsidae: Leiogalathea ) unveils Tethyan vicariance and evolutionary patterns shared by shallow‐water relatives

2020 ◽  
Vol 49 (3) ◽  
pp. 340-356
Author(s):  
Paula C. Rodríguez‐Flores ◽  
David Buckley ◽  
Enrique Macpherson ◽  
Laure Corbari ◽  
Annie Machordom
Keyword(s):  
Shallow Water ◽  
Deep Sea ◽  
Evolutionary Patterns ◽  
Squat Lobster
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