scholarly journals Model Simulation of Diurnal Vertical Migration Patterns of Different-Sized Colonies of Microcystis Employing a Particle Trajectory Approach

2013 ◽  
Vol 30 (4) ◽  
pp. 179-186 ◽  
Author(s):  
Yu Ching Chien ◽  
Shian Chee Wu ◽  
Wan Ching Chen ◽  
Chih Chung Chou
Keyword(s):  
Vertical Migration ◽  
Particle Trajectory ◽  
Model Simulation ◽  
Migration Patterns ◽  
Diurnal Vertical Migration ◽  
Trajectory Approach

Community Structure and Biomass of Euphausiids in the Bay of Fundy

1982 ◽  
Vol 39 (2) ◽  
pp. 326-334 ◽  
Author(s):  
D. W. Kulka ◽  
S. Corey ◽  
T. D. Iles
Keyword(s):  
Life History ◽  
Community Structure ◽  
Vertical Migration ◽  
High Intensity ◽  
Sampling Scheme ◽  
Bay Of Fundy ◽  
Migration Patterns ◽  
Life History Stages ◽  
Diurnal Vertical Migration ◽  
Meganyctiphanes Norvegica

Seven species of euphausiids were found in the Bay of Fundy: Meganyctiphanes norvegica, Thysanoessa inermis, T. longicaudata, T. raschii, T. gregaria, Euphausia krohnii, and Nematoscelis megalops (listed in descending order of abundance). A high-intensity sampling scheme during November and March facilitated detailed distributional studies which revealed that M. norvegica, T. inermis, and T. longicaudata each had a specific stationary center of abundance in the study area, and each species performed a different pattern of diurnal vertical migration. Meganyctiphanes norvegica formed 90% (constituting 70 kt) of the euphausiids. The last four species were occasional immigrants from areas south of the Bay of Fundy. From the relationships between life history stages, vertical migration patterns, distribution, and currents in the Fundy Region, we suggest that these euphausiid species form stocks.Key words: euphausiids, Meganyctiphanes norvegica, Thysanoessa inermis, Thysanoessa longicaudata, biomass, community structure, stock, Bay of Fundy

scholarly journals Diurnal vertical migration of some cladocerans in relation to the physico-chemical factors in a fish pond

1970 ◽  
Vol 20 (2) ◽  
pp. 147-154 ◽  
Author(s):  
AS Bhuiyan ◽  
S Akhter ◽  
MMA Quddus
Keyword(s):  
Key Words ◽  
Vertical Migration ◽  
Fish Pond ◽  
Chemical Parameters ◽  
Surface Layers ◽  
Diurnal Vertical Migration ◽  
Physico Chemical ◽  
Chemical Factors ◽  
Diurnal Movement ◽  
The Relationship

Diurnal vertical migration of four genera of cladocerans, namely Diaphanosoma sp., Daphnia sp., Moina sp. and Bosmina sp., during March to December, 2007 showed that the number of Diaphanosoma sp. was 501 units/1 in the surface layers, 172 units/l in the middle layers and 190 units/l in the bottom layers. The yearly number of Daphnia sp. in surface, middle and bottom layerss was 362 units/l, 46 units/l and 189 units/l respectively. In surface, bottom and middle layers, the number of Moina sp. was 159, 71 and 32 units/l, respectively. Bosmina sp. was 78 units/l in surface, 31 units/l in the middle and 33 units/l in the bottom layers. The number of Diaphanosoma sp., Daphnia sp., Moina sp., Bosmina sp., were 455, 149, 259 and 358 units/l, respectively in the morning, 63, 176, 142, 43 units/l at noon and 107, 55, 28, 59 units/l, respectively in the evening. Throughout the study period the cladocerans were always abundant near the surface during morning and evening. Among the factors responsible for the diurnal movement of cadoceran, light played the most important factor. The relationship between the physico-chemical factors and the cladoceran occurrence in the pond was also explored. Key words: Cladocera; Diurnal migration; Physico-chemical parameters; Fish pond DOI: http://dx.doi.org/10.3329/dujbs.v20i2.8975 DUJBS 2011; 20(2): 147-154

Review of information on diurnal vertical migration in the bignose shark (Carcharhinus altimus)

1996 ◽  
Vol 47 (4) ◽  
pp. 605 ◽  
Author(s):  
RC Anderson ◽  
JD Stevens
Keyword(s):  
Vertical Migration ◽  
Pelagic Zone ◽  
Benthic Species ◽  
Diurnal Vertical Migration

The bignose shark (Carcharhinus altimus) has been described in the literature as a deep-benthic species. Evidence is presented that C. altimus is a diurnal vertical migrator. It occurs near the bottom in about 90-500 m by day. At night, at least some individuals move into shallower water or up into the pelagic zone.

Bigdata-based investigation of heterogeneous migration and population distribution

2021 ◽  
Author(s):  
Zhiwei Fan ◽  
L. Xiong ◽  
Bo Zheng
Keyword(s):  
Census Data ◽  
Population Distribution ◽  
Model Simulation ◽  
Human Mobility ◽  
Economic Systems ◽  
Migration Patterns ◽  
Demographic Trend ◽  
Education Levels ◽  
The Uk ◽  
Migration Probability

Abstract Human mobility is very important in understanding complex social and economic systems. With massive empirical datasets from the China Household Finance Survey and the National Statistics in the UK, we construct a migration probability matrix, and analyze the heterogeneous migration patterns. We then develop a random walk model to dynamically simulate the population distribution. In the stationary state, the resulting population distribution is in good agreement with the real statistical data. For comparison, simulations with an optimized gravity model and other datasets such as the census data in China are also performed. Further, the model simulation is applied to predict the demographic trend with different education levels. Our method could be generally extended to other real communities and internet worlds.

scholarly journals ADCP observations of migration patterns of zooplankton in the Cretan Sea

2018 ◽  
Author(s):  
Emmanuel Potiris ◽  
Constantin Frangoulis ◽  
Alkiviadis Kalampokis ◽  
Manolis Ntoumas ◽  
Manos Pettas ◽  
...  
Keyword(s):  
Vertical Migration ◽  
Eastern Mediterranean ◽  
Vertical Motion ◽  
Lunar Cycle ◽  
Migration Patterns ◽  
Intimate Link ◽  
Seasonal Circulation ◽  
Continuous Presence ◽  
Adcp Observations ◽  
Cretan Sea

Abstract. The lack of knowledge of the mesopelagic layer inhabitants, especially of those performing strong vertical migration, is an acknowledged challenge as its incomplete representation leads to the exclusion of an active carbon and nutrient pathway from the surface to the deeper layers and reversely. The vertical migration of mesopelagic inhabitants (macro-planktonic and micro-nektonic) was observed by acoustical means in the epi- and mesopelagic layer of the open oligotrophic Cretan Sea (Eastern Mediterranean) for almost 2.5 years at the site of an operational fixed-point observatory located at 1500 m depth. The observed organisms were categorized in four groups according to their migration patterns. The variability of the migration patterns was inspected in relation to the physical and biological environmental conditions of the study area. The stratification of the water column does not act as a barrier for the vertical motion of the strongest migrants, moving up to 400 m every day. Instead, changes of light intensity (lunar cycle, daylight duration, cloudiness) and the presence of prey and predators seem to explain the observed daily, monthly and seasonal variability. The continuous presence of these organisms, yet capable of vertical motion and despite the profound seasonal circulation variability at the site of the observatory, implies their presence in the broader study area. The fundamental implications of the above for biogeochemical processing in oligotrophic seas due to the intimate link of the C and nutrient cycles, are discussed.

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