A one-dimensional model for the vertical distribution of pelagic fish eggs in the mixed layer

1983 ◽  
Vol 30 (6) ◽  
pp. 645-661 ◽  
Author(s):  
Svein Sundby
Keyword(s):  
Vertical Distribution ◽  
Mixed Layer ◽  
Pelagic Fish ◽  
Dimensional Model ◽  
Fish Eggs ◽  
One Dimensional ◽  
The Vertical Distribution

Application of a one-dimensional model to vertical distributions of cod eggs on the northeastern Newfoundland Shelf

1995 ◽  
Vol 52 (9) ◽  
pp. 1978-1989 ◽  
Author(s):  
John T. Anderson ◽  
Brad de Young
Keyword(s):  
Vertical Distribution ◽  
Stage Iv ◽  
Dimensional Model ◽  
Temperature Dependent ◽  
One Dimensional ◽  
Poor Condition ◽  
Vertical Distributions ◽  
The Vertical Distribution ◽  
Eggs And Larvae ◽  
Temperature Water

A one-dimensional model is developed to describe the vertical distribution of cod eggs and larvae on the northeastern Newfoundland Shelf. The model is dependent on egg buoyancy, temperature-dependent development, and age-dependent changes in density for eggs in good and poor condition. The model was fit to physical oceanographic data from the inner and outer shelf collected in 1991. Output from the model compared favourably with field observations. Cod eggs (stages I to III) were bimodally distributed above and below 100 m depth. Late stage eggs (stage IV) and larvae (5–6 mm) were only abundant in surface waters (<50 m). There was a progression from deeper to shallower depths as cod eggs developed through to larvae. Cod eggs observed deeper in the water column were thought to be in poor condition and were probably sinking. The model demonstrates that the vertical distribution of cod eggs is sensitive to changes in water temperature, water density (salinity), and egg condition.

On the numerical study of thermohydrodynamics and biochemistry of inland water bodies

2021 ◽  
Author(s):  
Daria Gladskikh ◽  
Evgeny Mortikov ◽  
Victor Stepanenko
Keyword(s):  
Mixed Layer ◽  
Numerical Study ◽  
Three Dimensional ◽  
Water Bodies ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
One Dimensional ◽  
Lake Model ◽  
Upper Mixed Layer ◽  
The One

&lt;p&gt;The study of thermodynamic and biochemical processes of inland water objects using one- and three-dimensional RANS numerical models was carried out both for idealized water bodies and using measurements data. The need to take into account seiche oscillations to correctly reproduce the deepening of the upper mixed layer in one-dimensional (vertical) models is demonstrated. We considered the one-dimensional LAKE model [1] and the three-dimensional model [2, 3, 4] developed at the Research Computing Center of Moscow State University on the basis of a hydrodynamic code combining DNS/LES/RANS approaches for calculating geophysical turbulent flows. The three-dimensional model was supplemented by the equations for calculating biochemical substances by analogy with the one-dimensional biochemistry equations used in the LAKE model. The effect of mixing processes on the distribution of concentration of greenhouse gases, in particular, methane and oxygen, was studied.&lt;/p&gt;&lt;p&gt;The work was supported by grants of the RF President&amp;#8217;s Grant for Young Scientists (MK-1867.2020.5, MD-1850.2020.5) and by the RFBR (19-05-00249, 20-05-00776).&amp;#160;&lt;/p&gt;&lt;p&gt;1. Stepanenko V., Mammarella I., Ojala A., Miettinen H., Lykosov V., Timo V. LAKE 2.0: a model for temperature, methane, carbon dioxide and oxygen dynamics in lakes // Geoscientific Model Development. 2016. V. 9(5). P. 1977&amp;#8211;2006.&lt;br&gt;2. Mortikov E.V., Glazunov A.V., Lykosov V.N. Numerical study of plane Couette flow: turbulence statistics and the structure of pressure-strain correlations // Russian Journal of Numerical Analysis and Mathematical Modelling. 2019. 34(2). P. 119-132.&lt;br&gt;3. Mortikov, E.V. Numerical simulation of the motion of an ice keel in stratified flow // Izv. Atmos. Ocean. Phys. 2016. V. 52. P. 108-115.&lt;br&gt;4. Gladskikh D.S., Stepanenko V.M., Mortikov E.V. On the influence of the horizontal dimensions of inland waters on the thickness of the upper mixed layer // Water Resourses. 2021.V. 45, 9 pages. (in press)&amp;#160;&lt;/p&gt;

scholarly journals ANALYSIS OF THE VERTICAL DISTRIBUTION OF THE ABUNDANCE OF SMALL PELAGIC FISH LARVAE IN THE GULF OF CALIFORNIA USING SUBMARINE VIDEOCAMERAS

2009 ◽  
Vol 24 (2) ◽  
pp. 153
Author(s):  
G. Aceves-Medina ◽  
C. J. Robinson ◽  
R. Palomares-García ◽  
J. Gómez-Gutierrez
Keyword(s):  
Vertical Distribution ◽  
Gulf Of California ◽  
Fish Larvae ◽  
Pelagic Fish ◽  
Small Pelagic Fish ◽  
Sardinops Sagax ◽  
Etrumeus Teres ◽  
Engraulis Mordax ◽  
The Vertical Distribution

Análisis de la distribucion vertical de la abundancia de larvas de peces pelágicos menores en el Golfo de California mediante videocámaras submarinas Se utilizaron dos tipos de videocámaras submarinas para estudiar la distribución y abundancia vertical de larvas de los peces pelágicos menores Engraulis mordax, Etrumeus teres y Sardinops sagax a 1 m de resolución, en una localidad en el norte del Golfo de California con condiciones de calma y alta densidad de sardinas adultas. La mayor abundancia promedio (900 larvas m -1 min -1 ) se encontró inmediatamente arriba de la termoclina (33 m) y la picnoclina (36 m), aparentemente no asociada al máximo de clorofila detectado en superficie, ni a la mayor densidad de peces adultos (10 -20 m). Las observaciones con video permitieron determinar la distribución vertical a una resolución imposible de obtener mediante muestreos con redes; sin embargo, esta es una técnica poco útil en zonas con elevada velocidad de las corrientes.

scholarly journals A model of Fe speciation and biogeochemistry at the Tropical Eastern North Atlantic Time-Series Observatory site

2009 ◽  
Vol 6 (10) ◽  
pp. 2041-2061 ◽  
Author(s):  
Y. Ye ◽  
C. Völker ◽  
D. A. Wolf-Gladrow
Keyword(s):  
Time Series ◽  
Vertical Distribution ◽  
North Atlantic ◽  
Decay Time ◽  
Particle Aggregation ◽  
Dust Particles ◽  
Dimensional Model ◽  
One Dimensional ◽  
Fe Speciation ◽  
Eastern North Atlantic

Abstract. A one-dimensional model of Fe speciation and biogeochemistry, coupled with the General Ocean Turbulence Model (GOTM) and a NPZD-type ecosystem model, is applied for the Tropical Eastern North Atlantic Time-Series Observatory (TENATSO) site. Among diverse processes affecting Fe speciation, this study is focusing on investigating the role of dust particles in removing dissolved iron (DFe) by a more complex description of particle aggregation and sinking, and explaining the abundance of organic Fe-binding ligands by modelling their origin and fate. The vertical distribution of different particle classes in the model shows high sensitivity to changing aggregation rates. Using the aggregation rates from the sensitivity study in this work, modelled particle fluxes are close to observations, with dust particles dominating near the surface and aggregates deeper in the water column. POC export at 1000 m is a little higher than regional sediment trap measurements, suggesting further improvement of modelling particle aggregation, sinking or remineralisation. Modelled strong ligands have a high abundance near the surface and decline rapidly below the deep chlorophyll maximum, showing qualitative similarity to observations. Without production of strong ligands, phytoplankton concentration falls to 0 within the first 2 years in the model integration, caused by strong Fe-limitation. A nudging of total weak ligands towards a constant value is required for reproducing the observed nutrient-like profiles, assuming a decay time of 7 years for weak ligands. This indicates that weak ligands have a longer decay time and therefore cannot be modelled adequately in a one-dimensional model. The modelled DFe profile is strongly influenced by particle concentration and vertical distribution, because the most important removal of DFe in deeper waters is colloid formation and aggregation. Redissolution of particulate iron is required to reproduce an observed DFe profile at TENATSO site. Assuming colloidal iron is mainly composed of inorganic colloids, the modelled colloidal to soluble iron ratio is lower that observations, indicating the importance of organic colloids.

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.

scholarly journals Diel variation in the vertical distribution and schooling behaviour of sardine (Sardina pilchardus) off Portugal

2007 ◽  
Vol 64 (5) ◽  
pp. 963-972 ◽  
Author(s):  
Juan Zwolinski ◽  
Alexandre Morais ◽  
Vitor Marques ◽  
Yorgos Stratoudakis ◽  
Paul G. Fernandes
Keyword(s):  
Vertical Distribution ◽  
Small Schools ◽  
Pelagic Fish ◽  
Diel Variation ◽  
Sardina Pilchardus ◽  
Cross Sectional ◽  
Fish Schools ◽  
School Expansion ◽  
Schooling Behaviour ◽  
The Vertical Distribution

Abstract Zwolinski, J., Morais, A., Marques, V., Stratoudakis, Y., and Fernandes, P. G. 2007. Diel variation in the vertical distribution and schooling behaviour of sardine (Sardina pilchardus) off Portugal. – ICES Journal of Marine Science, 64: 963–972. Diel patterns in the schooling behaviour and vertical distribution of pelagic fish schools were studied by examining their echotraces from repeated acoustic survey transects at three inshore sites off the Portuguese coast. At two sites, sardine was the dominant pelagic species, and echotrace characteristics of fish schools were similar to those reported in the literature. At the third site, where there was a multispecies pelagic assemblage that included sardine, there was more variability in several of the school descriptors. At all sites, fish schools expanded after sunset, enlarging their cross-sectional area along the horizontal plane and reducing their mean internal acoustic density, while maintaining their overall mean abundance. Downward migration was rapid (within 1 h) after sunset and simultaneous with school expansion. School-like aggregations with total backscattering similar to daytime schools were present throughout the night, although the proportion of small schools and scattered fish appeared to increase at that time. At dawn, sardine rose back up the water column and rapidly reformed into the typical daytime schools. This pattern of diel vertical migration is opposite to that described for most clupeoids worldwide. The implications of this behaviour on abundance estimation by acoustic monitoring surveys for small pelagic fish are discussed.

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