On the vertical distribution of pelagic tunicates in relation to the water masses in the western part of the Bay of Bengal

Hydrobiologia ◽  
1974 ◽  
Vol 44 (2-3) ◽  
pp. 209-214 ◽  
Author(s):  
P. V. Bhavanarayana
Keyword(s):  
Vertical Distribution ◽  
Bay Of Bengal ◽  
Water Masses ◽  
The Vertical Distribution

scholarly journals Vertical distribution of chlorophyll in dynamically distinct regions of the southern Bay of Bengal

2018 ◽  
Author(s):  
Venugopal Thushara ◽  
Puthenveettil Narayana Menon Vinayachandran ◽  
Adrian J. Matthews ◽  
Benjamin G. M. Webber ◽  
Bastien Y. Queste
Keyword(s):  
Sri Lanka ◽  
Vertical Distribution ◽  
Mixed Layer ◽  
Bay Of Bengal ◽  
Dominant Role ◽  
Chlorophyll Concentration ◽  
Ecosystem Model ◽  
Boreal Summer ◽  
South West Monsoon ◽  
The Vertical Distribution

Abstract. The Bay of Bengal (BoB) generally exhibits surface oligotrophy, due to nutrient limitation induced by strong salinity stratification. Nevertheless, there are hot spots of biological activity in the BoB where the monsoonal forcings are strong enough to break the stratification; one such region being the southern BoB, east of Sri Lanka. A recent field program conducted during the summer monsoon of 2016, as a part of the Bay of Bengal Boundary Layer Experiment (BoBBLE), provides a unique high-resolution dataset of the vertical distribution of chlorophyll in the southern BoB using ocean gliders along with shipboard CTD measurements. Observations were carried out for a duration of 12–20 days during a suppressed phase of the Boreal Summer Intraseasonal Oscillation (BSISO), along a longitudinal transect at 8° N, extending from 85.3–89° E, covering the dynamically active regions of the Sri Lanka Dome (SLD) and the South- west Monsoon Current (SMC). Mixing and upwelling induced by the monsoonal wind forcing enhanced chlorophyll concentrations (0.3–0.7 mg m−3) in the surface layers. Observations reveal the presence of prominent deep chlorophyll maxima (DCM; 0.3–1.2 mg m−3) at intermediate depths (20–50 m), generally below the mixed layer and above the thermocline, signifying the contribution of subsurface productivity on the biological carbon cycling in the BoB. The shape of chlorophyll profiles varied in different dynamical regimes indicating that the mechanisms determining the vertical distribution of chlorophyll are intricate; upwelling favoured sharp and intense DCM, whereas mixing resulted in diffuse and weaker DCM. Within the SLD, open ocean Ekman pumping and the doming of thermocline favoured a substantial increase in chlorophyll concentration. Farther east, the thermocline was deeper and moderate surface blooms were triggered by intermittent mixing events. Stabilising surface freshening events and barrier layer formation were often observed to inhibit the surface blooms. The pathway of SMC intrusion was marked by a distinct band of chlorophyll, indicating the advective effect of biologically rich Arabian Sea waters. The region of monsoon current exhibits the strongest DCM as well as the highest column-integrated chlorophyll. Observations suggest that the persistence of DCM in the southern BoB is promoted by surface oligotrophy, which reduces the self-shading effect of phytoplankton and shallow mixed layers, which prevent the vertical redistribution of subsurface phytoplankton. Results from a coupled physical-ecosystem model substantiate the dominant role of mixed layer processes associated with the monsoon in controlling the nutrient distribution and biological productivity in the southern BoB. The present study provides new insights into the vertical distribution of chlorophyll in the BoB, which is not captured in satellite mea- surements, emphasizing the need for extensive in situ sampling and ecosystem model-based efforts for a better understanding of the monsoonal bio-physical interactions and the potential climatic feedbacks.

Vertical Distribution of Atlantic Halibut (Hippoglossus hippoglossus) Eggs

1984 ◽  
Vol 41 (5) ◽  
pp. 798-804 ◽  
Author(s):  
Tore Haug ◽  
Elin Kjørsvik ◽  
Per Solemdal
Keyword(s):  
Vertical Distribution ◽  
Water Masses ◽  
Atlantic Halibut ◽  
Intermediate Water ◽  
Specific Density ◽  
Neutral Buoyancy ◽  
Hippoglossus Hippoglossus ◽  
Seawater Salinity ◽  
Water Layers ◽  
The Vertical Distribution

It is suggested that the vertical distribution of Atlantic halibut (Hippoglossus hippoglossus) eggs is determined by their specific density and that it is closely correlated to seawater salinity. In two deep North Norwegian fjords, only one halibut egg was found near the bottom (approximately 5200 m3 seawater filtered), while 278 eggs were found floating pelagically in intermediate water layers (approximately 190 000 m3 seawater filtered). Eggs were most abundant in water masses where temperature and salinity ranged between 4.5 and 7.0 °C and 33.8 and 35 0‰. Neutral buoyancy salinity measurements of living eggs corresponded approximately with the observed capture salinities. Mean capture salinity was 34.2 ± 0.3‰ (Malangen) and 34.5 ± 0.4‰ (Sørøysund). Egg diameters ranged from 3.06 to 3.49 mm.

scholarly journals Vertical distribution of chlorophyll in dynamically distinct regions of the southern Bay of Bengal

2019 ◽  
Vol 16 (7) ◽  
pp. 1447-1468 ◽  
Author(s):  
Venugopal Thushara ◽  
Puthenveettil Narayana Menon Vinayachandran ◽  
Adrian J. Matthews ◽  
Benjamin G. M. Webber ◽  
Bastien Y. Queste
Keyword(s):  
Sri Lanka ◽  
Vertical Distribution ◽  
Bay Of Bengal ◽  
Dominant Role ◽  
Active Regions ◽  
Ecosystem Model ◽  
Ocean Dynamics ◽  
Nutrient Distribution ◽  
Enhanced Surface ◽  
The Vertical Distribution

Abstract. The Bay of Bengal (BoB) generally exhibits surface oligotrophy due to nutrient limitation induced by strong salinity stratification. Nevertheless, there are hotspots of high chlorophyll in the BoB where the monsoonal forcings are strong enough to break the stratification; one such region is the southern BoB, east of Sri Lanka. A recent field programme conducted during the summer monsoon of 2016, as a part of the Bay of Bengal Boundary Layer Experiment (BoBBLE), provides a unique high-resolution dataset of the vertical distribution of chlorophyll in the southern BoB using ocean gliders along with shipboard conductivity–temperature–depth (CTD) measurements. Observations were carried out for a duration of 12–20 days, covering the dynamically active regions of the Sri Lanka Dome (SLD) and the Southwest Monsoon Current (SMC). Mixing and upwelling induced by the monsoonal wind forcing enhanced surface chlorophyll concentrations (0.3–0.7 mg m−3). Prominent deep chlorophyll maxima (DCM; 0.3–1.2 mg m−3) existed at intermediate depths (20–50 m), signifying the contribution of subsurface productivity to the biological carbon cycling in the BoB. The shape of chlorophyll profiles varied in different dynamical regimes; upwelling was associated with sharp and intense DCM, whereas mixing resulted in a diffuse and weaker DCM. Within the SLD, open-ocean Ekman suction favoured a substantial increase in chlorophyll. Farther east, where the thermocline was deeper, enhanced surface chlorophyll was associated with intermittent mixing events. Remote forcing by the westward propagating Rossby waves influenced the upper-ocean dynamics and chlorophyll distribution in the southern BoB. Stabilizing surface freshening events and barrier-layer formation often inhibited the generation of surface chlorophyll. The pathway of the SMC intrusion was marked by a distinct band of chlorophyll, indicating the advective effect of biologically rich Arabian Sea waters. The region of the monsoon current exhibited the strongest DCM as well as the highest column-integrated chlorophyll. Observations suggest that the persistence of DCM in the southern BoB is promoted by surface oligotrophy and shallow mixed layers. Results from a coupled physical–ecosystem model substantiate the dominant role of mixed layer processes associated with the monsoon in controlling the nutrient distribution and biological productivity in the southern BoB. The present study provides new insights into the vertical distribution of chlorophyll in the BoB, emphasizing the need for extensive in situ sampling and ecosystem model-based efforts for a better understanding of the biophysical interactions and the potential climatic feedbacks.

The vertical distribution of tritium in water vapor in the lower troposphere

Tellus ◽  
1970 ◽  
Vol 22 (6) ◽  
pp. 699-706 ◽  
Author(s):  
Wayne E. Bradley ◽  
Glenn E. Stout
Keyword(s):  
Water Vapor ◽  
Vertical Distribution ◽  
Lower Troposphere ◽  
The Vertical Distribution
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