Flushing rate and salinity may control the blooms of the toxic dinoflagellate Alexandrium tamarense in a river/estuary in Osaka Bay, Japan

2013 ◽  
Vol 69 (6) ◽  
pp. 727-736 ◽  
Author(s):  
Keigo Yamamoto ◽  
Hirotaka Tsujimura ◽  
Masaki Nakajima ◽  
Paul J. Harrison
Keyword(s):  
River Estuary ◽  
Alexandrium Tamarense ◽  
Toxic Dinoflagellate ◽  
Osaka Bay ◽  
Flushing Rate

ANALYSIS OF MARINE PHYTOPLANKTON IN THE YODO RIVER ESTUARY BY THE NUMERICAL ECOSYSTEM MODEL

2017 ◽  
Author(s):  
Mitsuru Hayashi ◽  
Mitsuru Hayashi ◽  
Tomomi Miyawaki ◽  
Tomomi Miyawaki ◽  
Koga Ryutaro ◽  
...  
Keyword(s):  
Temporal Variation ◽  
River Estuary ◽  
Ecosystem Model ◽  
Flood Tide ◽  
Marine Phytoplankton ◽  
Alexandrium Tamarense ◽  
In Situ Observation ◽  
Shellfish Poisoning ◽  
Downstream Side ◽  
Osaka Bay

In order to understand the temporal variation of the physics and fluid structure of Yodo River estuary in detail, we had made in-situ observation. And the temporal variation of Alexandrium tamarense which cause the shellfish poisoning of natural freshwater clam was analyzed by the numerical ecosystem model which is considered the salinity effects. Stratification develops in the downstream side. Chl.a concentration is high in the seawater region. A. tamarense is detected in the downstream side. The numerical ecosystem model including the salinity effect for A. tamarense was formulated. A. tamarense grow only in the bottom layer in daytime, and the daily mean of it is 7 % of it transported from Osaka Bay. A. tamarense is transported to the upstream in flood tide. 81 % of it transported from Osaka Bay goes to the upstream zone. Much A. tamarense transported to the upstream zone in nighttime due to the vertical migration. Therefore when it is the flood tide in nighttime, more of A. tamarense might be transported to the upstream zone.

ANALYSIS OF MARINE PHYTOPLANKTON IN THE YODO RIVER ESTUARY BY THE NUMERICAL ECOSYSTEM MODEL

2017 ◽  
Author(s):  
Mitsuru Hayashi ◽  
Mitsuru Hayashi ◽  
Tomomi Miyawaki ◽  
Tomomi Miyawaki ◽  
Koga Ryutaro ◽  
...  
Keyword(s):  
Temporal Variation ◽  
River Estuary ◽  
Ecosystem Model ◽  
Flood Tide ◽  
Marine Phytoplankton ◽  
Alexandrium Tamarense ◽  
In Situ Observation ◽  
Shellfish Poisoning ◽  
Downstream Side ◽  
Osaka Bay

In order to understand the temporal variation of the physics and fluid structure of Yodo River estuary in detail, we had made in-situ observation. And the temporal variation of Alexandrium tamarense which cause the shellfish poisoning of natural freshwater clam was analyzed by the numerical ecosystem model which is considered the salinity effects. Stratification develops in the downstream side. Chl.a concentration is high in the seawater region. A. tamarense is detected in the downstream side. The numerical ecosystem model including the salinity effect for A. tamarense was formulated. A. tamarense grow only in the bottom layer in daytime, and the daily mean of it is 7 % of it transported from Osaka Bay. A. tamarense is transported to the upstream in flood tide. 81 % of it transported from Osaka Bay goes to the upstream zone. Much A. tamarense transported to the upstream zone in nighttime due to the vertical migration. Therefore when it is the flood tide in nighttime, more of A. tamarense might be transported to the upstream zone.

scholarly journals Using flushing rate to investigate spring-neap and spatial variations of gravitational circulation and tidal exchanges in an estuary

2010 ◽  
Vol 14 (8) ◽  
pp. 1465-1476 ◽  
Author(s):  
D. C. Shaha ◽  
Y.-K. Cho ◽  
G.-H. Seo ◽  
C.-S. Kim ◽  
K. T. Jung
Keyword(s):  
Neap Tide ◽  
Spring Tide ◽  
Vertical Mixing ◽  
River Estuary ◽  
Spatial Variations ◽  
Tidal Amplitude ◽  
Gravitational Circulation ◽  
Flushing Rate ◽  
Rapid Exchange ◽  
Dispersive Flux

Abstract. Spring-neap and spatial variations of gravitational circulation and tidal exchanges in the Sumjin River Estuary (SRE) were investigated using the flushing rate. The flushing rate was calculated between multiple estuarine segments and the adjacent bay to examine the spatial variation of two exchanges. The strength of gravitational circulation and tidal exchanges modulated significantly between spring and neap tides, where stratification alternated between well-mixed and highly-stratified conditions over the spring-neap cycle. Tide-driven dispersive flux of salt dominated over gravitational circulation exchange near the mouth during spring tide due to the larger tidal amplitude that caused well-mixed conditions and rapid exchange. In contrast, the central and inner regimes were found to be partially stratified during spring tide due to the reduction in tidal amplitude where both gravitational circulation and tidal exchanges were important in transporting salt. The combined contributions of two fluxes were also found during neap tide along the SRE due to the significant reduction in vertical mixing that accompanied strong stratification. Gravitational circulation exchange almost entirely dominated in transporting salt at the upstream end during spring and neap tides.

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