scholarly journals A Study of the Distributions of Two Endangered Sea Skaters Halobates matsumurai Esaki and Asclepios shiranui (Esaki) (Hemiptera: Gerridae: Halobatinae) with Special Reference to Their Strategies to Cope with Tidal Currents

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Terumi Ikawa ◽  
Yuichi Nozoe ◽  
Natsuko Yamashita ◽  
Namiko Nishimura ◽  
Satoshi Ohnoki ◽  
...  
Keyword(s):  
Special Reference ◽  
Intertidal Zone ◽  
Tidal Currents ◽  
Open Ocean ◽  
Survival Strategies ◽  
Close Relative ◽  
Coastal Species ◽  
Coastal Sea ◽  
Oceanic Species

There exist surprisingly few marine insects, most of which are confined to the intertidal zone. Halobates is the only genus to have some oceanic species along with some coastal species. Among the coastal sea skaters, that is, genus Halobates and its close relative, genus Asclepios, there are variations in their affinity for the shore. We have studied the distributions of two endangered Japanese sea skaters, Halobates matsumurai and Asclepios shiranui in Kujukushima, where they cooccur in coves. To compare their survival strategies at sea, we especially noted differences in their distributions along the shore during high and low tides. The results show that A. shiranui tended to remain along the shore during low tide. This species appeared to cling to the shore against the ebb current and to stay in the protected coves. By contrast, H. matsumurai tended to leave the shore during low tide. Notably, some adults were found skating outside the coves. The strategy of H. matsumurai appeared to be leaving with the ebb current even beyond the coves, thereby using more resources and enlarging its habitat. Some such coastal Halobates might have acquired the ability to live on the open ocean clearly independent of the shoreline.

The dynamics of microbial and herbivorous food webs in a coastal sea with special reference to intermittent nutrient supply from bottom intrusion

2004 ◽  
Vol 38 (4) ◽  
pp. 485-493 ◽  
Author(s):  
Shin-ichi Nakano ◽  
Yuji Tomaru ◽  
Toshiya Katano ◽  
Atsushi Kaneda ◽  
Wataru Makino ◽  
...  
Keyword(s):  
Special Reference ◽  
Food Webs ◽  
Nutrient Supply ◽  
Coastal Sea

scholarly journals Relating Hydrodynamic Forcing and Topographic Response for Tide-Dominated Sandy Beaches

2020 ◽  
Vol 8 (3) ◽  
pp. 151 ◽  
Author(s):  
Evelien Brand ◽  
Anne-Lise Montreuil ◽  
Rik Houthuys ◽  
Margaret Chen
Keyword(s):  
Intertidal Zone ◽  
Spring Tide ◽  
Field Measurements ◽  
Sandy Beaches ◽  
Tidal Currents ◽  
Sediment Supply ◽  
Wave Steepness ◽  
Natural Sediment ◽  
Order Of Magnitude ◽  
Study Sites

To relate hydrodynamic forcing and topographic response for a tide-dominated sandy beach, extensive field measurements were carried out in the intertidal zone. Hydrodynamics and beach topography were monitored during a total of 12 weeks at two different study sites: one with a featureless intertidal zone and one with intertidal bars. The results of both study sites indicate that the intertidal beach grows when wave steepness is small, whereas it erodes when wave steepness is large. Spring-neap variations in tidal current direction heavily distort this trend: strong spring tidal currents transport sediment away from the beach, resulting in enhanced erosion. Tide-induced beach volume changes are on the same order of magnitude as wave-induced changes. Besides waves and tides, the effect of variations in the amount of sediment supply is substantial, with enhanced accretion when the sediment supply is large. The effect of variations in sediment supply on the intertidal beach topography is subordinate to the effect of waves and tide, though. From this study, it is concluded that larger waves are primarily erosive, but they can also enhance the natural sediment supply. Furthermore, it is found that tidal currents can be equally important as waves in shaping the beach topography, especially during spring tide on macrotidal beaches.

Bioluminescence of the oceanic apogonid fishesHowella brodieiandFlorenciella lugubris

1992 ◽  
Vol 72 (1) ◽  
pp. 139-148 ◽  
Author(s):  
Peter J. Herring
Keyword(s):  
Shallow Water ◽  
Systematic Position ◽  
Luminescent Material ◽  
Posterior Intestine ◽  
Pyloric Caeca ◽  
Coastal Species ◽  
As Species ◽  
The Family ◽  
Oceanic Species ◽  
Neritic Species

The pyloric caeca and posterior intestine ofHowella brodieiare bioluminescent, and are associated with internal reflective tissues. The bioluminescence is not bacterial in origin. Unlike that of several shallow water apogonids, it does not depend uponVargulaluciferin.Florenciella lugubrishas bioluminescent oesophageal diverticula and is able to eject a pulse of luminescent material from beneath the operculum.The luminescence of the two species is compared with that of other perciform fishes.IntroductionThe perciform family Apogonidae (cardinal fishes) contains several bioluminescent coastal species in the Indopacific generaSiphamia, Rhabdamia, Archamia, andApogon. Their oceanic relatives are less well known and their systematic position is still a matter of some conjecture.Howellahas been assigned to the Apogonidae but has also been included in the Moronidae (Tortonese, 1986), and, more recently, in the Percichthyidae (Post & Quéro, 1991). Some authors have followed Mead & De Falla (1965) in assigning the oceanic apogonid-like fishes to the family Cheilodipteridae(e.g.Fedoryako, 1976), in recognition of the fact that they ‘are so different from their coastal relatives that comparison is pointless’ (Mead & De Falla, 1965).Bioluminescence has not been described in detail in any of the oceanic species. Mayer (1974) reported that one of the pyloric caeca inEpigonus macropswas separated from the others and associated with reflective structures. This strongly suggested that it was bioluminescent, based on comparisons with known luminescent shallow water perciforms, such as species ofPempherisandParapriacanthus.Mead & De Falla (1965) described a ventral reflective strip inRosenblattia robustawhich, by analogy with similar appearances in luminous neritic species, they considered a possible indication of bioluminescence.

scholarly journals I. On tidal currents in the ocean

1888 ◽  
Vol 43 (258-265) ◽  
pp. 340-347
Keyword(s):  
Gulf Stream ◽  
Tidal Currents ◽  
Open Ocean ◽  
General Direction ◽  
Oceanic Currents

It is frequently asserted and commonly believed that tidal currents do not exist in the open ocean or in waters remote from land. Oceanic currents, that is, streams which set more or less constantly in one general direction, are well-known and, from their importance to navigation, have been the objects of much study. Chief among these may be mentioned the Gulf Stream and the Equatorial Currents in both oceans.

Observed coastal sea level changes in Southeast Asia from retracked altimetry over 2002-present

2020 ◽  
Author(s):  
Yvan Gouzènes ◽  
Fabien Léger ◽  
Anny Cazenave ◽  
Florence Birol ◽  
Marcello Passaro ◽  
...  
Keyword(s):  
Time Series ◽  
Southeast Asia ◽  
Sea Level ◽  
Processing System ◽  
Leading Edge ◽  
Open Ocean ◽  
Small Scale ◽  
Coastal Zones ◽  
Sea Level Changes ◽  
Coastal Sea

<p>We present results of contemporary coastal sea level changes along the coasts of different<br>regions of Southeast Asia derived from a dedicated reprocessing of satellite altimetry data.<br>This work is performed in the context of the ESA ‘Climate Change Initiative’ sea level project<br>dedicated to provide altimetry-based sea level time series in the world coastal zones. Here is<br>focus on Southeast Asian Seas. High-frequency (20 Hz) sea level data from the Jason-1,<br>Jason-2 and Jason-3 missions are considered. The data are first retracked using the ALES<br>adaptive leading edge subwaveform retracker and further combined with the X-TRACK<br>processing system developed to optimize the accuracy of the sea level time series in coastal<br>oceans. Rates of sea level change are estimated over the period 2002-present along the Jasontracks,<br>from the open ocean to the coast. Different coastal sea level trend behaviors are<br>observed over the study period: constant trends from open ocean to the coast, sometimes<br>decreasing trends, or increasing trends within the last few km to the coast. We compare the<br>computed coastal trends in Southeast Asia with results we previously obtained in other<br>regions (Mediterranean Sea, Western Africa, Northeastern Europe). We further discuss the<br>various small-scale processes able to explain departure of the coastal sea level rate from the<br>offshore (open ocean) rate.</p>

The dynamics of microbial and herbivorous food webs in a coastal sea with special reference to intermittent nutrient supply from bottom intrusion

2005 ◽  
Vol 38 (4) ◽  
pp. 485-493 ◽  
Author(s):  
Shin-ichi Nakano ◽  
Yuji Tomaru ◽  
Toshiya Katano ◽  
Atsushi Kaneda ◽  
Wataru Makino ◽  
...  
Keyword(s):  
Special Reference ◽  
Food Webs ◽  
Nutrient Supply ◽  
Coastal Sea

scholarly journals Leaky Slope Waves and Sea Level: Unusual Consequences of the Beta Effect along Western Boundaries with Bottom Topography and Dissipation

2020 ◽  
Vol 50 (1) ◽  
pp. 217-237 ◽  
Author(s):  
Anthony Wise ◽  
Chris W. Hughes ◽  
Jeff A. Polton ◽  
John M. Huthnance
Keyword(s):  
Sea Level ◽  
High Latitude ◽  
Bottom Topography ◽  
Open Ocean ◽  
Meridional Overturning Circulation ◽  
Western Boundary ◽  
Ocean Variability ◽  
Coastal Sea ◽  
Shelf Waves ◽  
And Sea Level

ABSTRACTCoastal trapped waves (CTWs) carry the ocean’s response to changes in forcing along boundaries and are important mechanisms in the context of coastal sea level and the meridional overturning circulation. Motivated by the western boundary response to high-latitude and open-ocean variability, we use a linear, barotropic model to investigate how the latitude dependence of the Coriolis parameter (β effect), bottom topography, and bottom friction modify the evolution of western boundary CTWs and sea level. For annual and longer period waves, the boundary response is characterized by modified shelf waves and a new class of leaky slope waves that propagate alongshore, typically at an order slower than shelf waves, and radiate short Rossby waves into the interior. Energy is not only transmitted equatorward along the slope, but also eastward into the interior, leading to the dissipation of energy locally and offshore. The β effect and friction result in shelf and slope waves that decay alongshore in the direction of the equator, decreasing the extent to which high-latitude variability affects lower latitudes and increasing the penetration of open-ocean variability onto the shelf—narrower continental shelves and larger friction coefficients increase this penetration. The theory is compared with observations of sea level along the North American east coast and qualitatively reproduces the southward displacement and amplitude attenuation of coastal sea level relative to the open ocean. The implications are that the β effect, topography, and friction are important in determining where along the coast sea level variability hot spots occur.

Sign in / Sign up

Export Citation Format

Share Document