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.

Hydrographic Effects on the Vertical Distribution of Haddock (Melanogrammus aeglefinus) Eggs and Larvae on the Southwestern Scotian Shelf

1989 ◽  
Vol 46 (S1) ◽  
pp. s82-s92 ◽  
Author(s):  
Kenneth T. Frank ◽  
Fred H. Page ◽  
Jeff K. McRuer
Keyword(s):  
Vertical Distribution ◽  
Depth Distribution ◽  
Stage Iv ◽  
Melanogrammus Aeglefinus ◽  
Juvenile Period ◽  
Embryonic Period ◽  
Near Shore ◽  
The Vertical Distribution ◽  
Eggs And Larvae ◽  
Haddock Melanogrammus Aeglefinus

Relationships between the density (sigma-t) structure of the water column and the depth distribution of haddock (Melanogrammus aeglefinus) eggs and larvae in May of 1985 and 1986 were investigated. During the early embryonic period the egg concentration decreased exponentially with depth; this contrasted sharply with stage IV eggs which showed a subsurface maximum, the location of which was determined by their specific gravity. Depth of the centre-of-mass (Zcrn) of stage IV eggs ranged from 13 to 47 m over the survey area whereas the sigma-t associated with the Zcm depth varied only slightly (CV = 0.4%) about a mean of 25.58. In stratified offshore waters, haddock eggs were aggregated at middepth but exhibited a progressively more uniform vertical distribution towards the weakly stratified nearshore. Where low-density water (sigma-t < 25.5) occurred near-shore eggs were concentrated at the deepest sampling stratum, suggesting that peak egg concentrations were below this level or possibly on the bottom. The depth distribution of haddock larvae was identical to that of late-stage eggs and was therefore established by buoyancy changes occurring during the embryonic period. Day and night Zcm was similar, averaging 28 and 31 m, respectively, and stability of the depth distribution of larvae appears to persist well into the juvenile period.

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.

Vertical Distributions in Number of Soil Microorganism with Caragana in the Hobq of Inner Mongolia

2014 ◽  
Vol 955-959 ◽  
pp. 3581-3585
Author(s):  
Xiao Tong Wu ◽  
Ya Ting Dai ◽  
Yu Qin Shao ◽  
Jia Yin Lu ◽  
Miao Miao Hou
Keyword(s):  
Organic Matter ◽  
Vertical Distribution ◽  
Inner Mongolia ◽  
Soil Microorganisms ◽  
Soil Microorganism ◽  
Aerobic Bacteria ◽  
Vertical Distributions ◽  
The Vertical Distribution

The study investigated the vertical distribution of soil microorganism on Caragana rhizosphere at Hobq of ORDOS. The result showed that microbial vertical distribution was obvious. The order of vertical distribution in number of aerobic bacteria were 0-10cm>20-30cm>10-20cm>30-40cm, and there were significant differences between microorganisms in 0-10cm, 10-20cm and 30-40cm underground; the number of aerobic bacteria in 0-10cm underground was higher than 10-20cm, 20-30cm and 30-40cm by 1.48,1.41 and 1.86. The order of vertical distribution in number of fungi were 0-10cm>10-20cm>20-30cm>30-40cm, and there were significant differences between 0-10 cm and 20-30cm、30-40cm, and between 10-20 cm and 20-30cm、30-40cm. the number of fungi in 0-10cm underground was higher than 10-20cm, 20-30cm and 30-40cm by 1.01, 3.60 and 5.37. The order of vertical distribution in number of Actinomycetes was 0-10cm>10-20cm>20-30cm>30-40cm, and the differences between 0-10 cm and 10-20cm, 20-30cm, 30-40cm were significant; the number of Actinomycetes in 0-10cm underground was higher than 10-20cm, 20-30cm and 30-40cm by 1.54,1.66 and 2.60. The distribution and quantity of soil microorganisms might be influenced by organic matter contents.

scholarly journals Size-Fractionated Filtration Combined with Molecular Methods Reveals the Size and Diversity of Picophytoplankton

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1280
Author(s):  
Xinze Shuwang ◽  
Jun Sun ◽  
Yuqiu Wei ◽  
Congcong Guo
Keyword(s):  
Flow Cytometry ◽  
Particle Size ◽  
Vertical Distribution ◽  
High Throughput ◽  
High Throughput Sequencing ◽  
Hypervariable Region ◽  
Pcr Amplification ◽  
Euphotic Zone ◽  
Vertical Distributions ◽  
The Vertical Distribution

In this study, flow cytometry (FCM) and size-fractionated filtration, together with high-throughput molecular sequencing methods (SM), were used to investigate picophytoplankton. A particle separation filter and a higher-throughput sequencing method were used to evaluate the composition of a euphotic zone of picophytoplankton—especially picoeukaryotic phytoplankton—in the Western Pacific, and the results of flow cytometry, which is a classic way to detect picophytoplankton, were used as a standard to evaluate the reliability of the results of the SMs. Within a water column of 200 m, six water depths (5, 25, 50, 113 (DCM), 150, and 200 m) were established. In order to further study the particle size spectra of the picophytoplankton, size-fractionated filtration was used to separate water samples from each water depth into three particle size ranges: 0.2–0.6, 0.6–1.2, and 1.2–2 μm. A total of 36 (6 × 3 × 2) samples were obtained through PCR amplification of the 18S rRNA V4 hypervariable region and 16S rRNA, which were biased toward phytoplankton plastids, and then high-throughput sequencing was performed. The estimation of the picophytoplankton diameter relied on forward scattering (FSC) through FCM. The estimation of the vertical distribution and diameter of the picophytoplankton using the SM was consistent with the results with FCM; thus, we believe that the estimation of picophytoplankton composition with the SM has value as a reference, although the size-fractionated filtration seemed to cause some deviations. In addition to Prochlorococcus and Synechococcus, the SM was used to evaluate the composition of picoeukaryotic phytoplankton, which mainly included Prymnesiophycea (Haptophyta) (38.15%), Cryptophyceae (Cryptophyta) (22.36%), Dictyochophyceae (Chrysophyta) (12.22%), and Mamiellophyceae (Chlorophyta) (3.31%). In addition, the SM also detected Dinophyceae (Dinoflagellata) (11.69%) sequences and a small number of Bacillariophyceae (Diatom) (1.64%) sequences, which are generally considered to have large particle sizes. The results of the SM also showed that the picoeukaryotic phytoplankton were not evenly distributed in the euphotic layer, and the vertical distributions of the different picoeukaryotic phytoplankton were different. An analysis of correlations with environmental factors showed that temperature was the main environmental factor controlling the vertical distribution of picophytoplankton.

Predicting the Vertical Distribution of Fish Populations: Analysis of Cisco, Coregonus artedii, and Yellow Perch, Perca flavescens

1985 ◽  
Vol 42 (6) ◽  
pp. 1178-1188 ◽  
Author(s):  
Lars G. Rudstam ◽  
John J. Magnuson
Keyword(s):  
Vertical Distribution ◽  
Yellow Perch ◽  
Factor Model ◽  
Perca Flavescens ◽  
Fish Population ◽  
Lake Mendota ◽  
Vertical Distributions ◽  
Preferred Temperatures ◽  
Coregonus Artedii ◽  
The Vertical Distribution

We develop a model based on fish behavior in temperature and oxygen gradients that yields quantitative predictions of the vertical distribution of a fish population throughout the water column. The model was tested against observed vertical distributions of cisco, Coregonus artedii, and yellow perch, Perca flavescens, in 1981 and 1982 from five Wisconsin lakes. In some cases, the model seemed adequate for cisco, but in most cases, they occupied a temperature lower than their final preferendum. Occupation of lower temperature is consistent with a response to less than ad libitum food rations expected in these oligotrophy to mesotrophic lakes. In Lake Mendota, which is eutrophic with an anaerobic hypolimnion, cisco occupied temperatures higher than predicted by the model. For perch distributions, avoidance of high light intensities appears important. We did not observe effects of interspecific segregation between cisco and perch in their vertical distributions beyond that expected from differences in their preferred temperatures. Deviations of actual distributions from predictions of our relatively simplistic two-factor model can be used to help identify and evaluate other important physical and biotic factors influencing vertical distributions.

scholarly journals Application of Number-Size (N-S) Fractal Model to Quantify of the Vertical Distributions of Cu and Mo in Nowchun Porphyry Deposit (Kerman, Se Iran) / Zastosowanie modelu fraktalnego n-s (liczba-rozmiar) do ilościowego określenia pionowego rozkładu Cu i Mo w złożu porfirowym (Kerman, Iran)

2013 ◽  
Vol 58 (1) ◽  
pp. 89-105 ◽  
Author(s):  
Lili Daneshvar Saein ◽  
Iraj Rasa ◽  
Nematolah Rashidnejad Omran ◽  
Parviz Moarefvand ◽  
Peyman Afzal ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Mineral Exploration ◽  
Fractal Model ◽  
Skewed Distribution ◽  
Threshold Values ◽  
Multimodal Distribution ◽  
Porphyry Deposit ◽  
Vertical Distributions ◽  
The Vertical Distribution

Determination of the vertical distribution of geochemical elemental concentrations is of fundamental importance in mineral exploration. In this paper, eight mineralized boreholes from the Nowchun Cu-Mo porphyry deposit, SE Iran, were used to identify of the vertical distribution directional properties of Cu and Mo values using number-size (N-S) fractal model. The vertical distributions of Cu and Mo in the mineralized boreholes show a positively skewed distribution in the former and a multimodal distribution in the latter types. Elemental threshold values for the mineralized boreholes were computed by fractal model and compared with the statistical methods based on the data obtained from chemical analysis of samples. Elemental distributions are not normal in these boreholes and their median equal to Cu and Mo thresholds. The results of N-S fractal analysis reveal that Cu and Mo values in mineralized boreholes are multifractals in nature. There are at least three geochemical populations for Cu and Mo in the boreholes and Cu and Mo thresholds have ranges between 0.07%-0.3% and 50-200 ppm, respectively. The results obtained by N-S fractal model were compared with geological observations in the boreholes. Major Cu and Mo enrichment correlated by monzonitic rocks and high amounts of observed Cu and Mo ores (Chalcopyrite and molybdenite) in the boreholes.

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