scholarly journals Influence of Barotropic Tidal Currents on Transport and Accumulation of Floating Microplastics in the Global Open Ocean

2020 ◽  
Vol 125 (2) ◽  
Author(s):  
Miriam F. Sterl ◽  
Philippe Delandmeter ◽  
Erik Sebille
Keyword(s):  
Tidal Currents ◽  
Open Ocean

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.

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.

Drivers of diversity gradients of a highly mobile marine assemblage in a mesoscale seascape

2020 ◽  
Vol 638 ◽  
pp. 149-164
Author(s):  
GM Svendsen ◽  
M Ocampo Reinaldo ◽  
MA Romero ◽  
G Williams ◽  
A Magurran ◽  
...  
Keyword(s):  
Environmental Gradients ◽  
Regression Tree ◽  
Demersal Fish ◽  
Open Ocean ◽  
Shared Resources ◽  
Thermal Front ◽  
Boosted Regression Tree ◽  
Diversity Gradients ◽  
Α Diversity ◽  
Bottom Depth

With the unprecedented rate of biodiversity change in the world today, understanding how diversity gradients are maintained at mesoscales is a key challenge. Drawing on information provided by 3 comprehensive fishery surveys (conducted in different years but in the same season and with the same sampling design), we used boosted regression tree (BRT) models in order to relate spatial patterns of α-diversity in a demersal fish assemblage to environmental variables in the San Matias Gulf (Patagonia, Argentina). We found that, over a 4 yr period, persistent diversity gradients of species richness and probability of an interspecific encounter (PIE) were shaped by 3 main environmental gradients: bottom depth, connectivity with the open ocean, and proximity to a thermal front. The 2 main patterns we observed were: a monotonic increase in PIE with proximity to fronts, which had a stronger effect at greater depths; and an increase in PIE when closer to the open ocean (a ‘bay effect’ pattern). The originality of this work resides on the identification of high-resolution gradients in local, demersal assemblages driven by static and dynamic environmental gradients in a mesoscale seascape. The maintenance of environmental gradients, specifically those associated with shared resources and connectivity with an open system, may be key to understanding community stability.

MAPPING TIDAL CURRENTS AND RESIDUAL CURRENTS BY USE OF COASTAL ACOUSTIC TOMOGRAPHY

2017 ◽  
Author(s):  
Xiao-Hua Zhu ◽  
Xiao-Hua Zhu ◽  
Ze-Nan Zhu ◽  
Ze-Nan Zhu ◽  
Xinyu Guo ◽  
...  
Keyword(s):  
Shallow Water ◽  
Shallow Water Equations ◽  
Mean Amplitude ◽  
Momentum Equation ◽  
Tidal Currents ◽  
Acoustic Tomography ◽  
Mean Values ◽  
Residual Currents ◽  
Water Depths ◽  
Deep Area

A coastal acoustic tomography (CAT) experiment for mapping the tidal currents in the Zhitouyang Bay was successfully carried out with seven acoustic stations during July 12 to 13, 2009. The horizontal distributions of tidal current in the tomography domain are calculated by the inverse analysis in which the travel time differences for sound traveling reciprocally are used as data. Spatial mean amplitude ratios M2 : M4 : M6 are 1.00 : 0.15 : 0.11. The shallow-water equations are used to analyze the generation mechanisms of M4 and M6. In the deep area, velocity amplitudes of M4 measured by CAT agree well with those of M4 predicted by the advection terms in the shallow water equations, indicating that M4 in the deep area where water depths are larger than 60 m is predominantly generated by the advection terms. M6 measured by CAT and M6 predicted by the nonlinear quadratic bottom friction terms agree well in the area where water depths are less than 20 m, indicating that friction mechanisms are predominant for generating M6 in the shallow area. Dynamic analysis of the residual currents using the tidally averaged momentum equation shows that spatial mean values of the horizontal pressure gradient due to residual sea level and of the advection of residual currents together contribute about 75% of the spatial mean values of the advection by the tidal currents, indicating that residual currents in this bay are induced mainly by the nonlinear effects of tidal currents.

Marginal Sea-Open Ocean Exchange

2002 ◽  
Author(s):  
Michael A. Spall
Keyword(s):  
Open Ocean ◽  
Marginal Sea
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