scholarly journals A comparison of plant production estimates using14C and phosphate data

1957 ◽  
Vol 36 (2) ◽  
pp. 233-241 ◽  
Author(s):  
John H. Steele
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Organic Production ◽  
Plant Production ◽  
Carbon Uptake ◽  
Vertical Distributions ◽  
Filtering Rates ◽  
The Vertical Distribution

Organic production in the sea can be measured by studying the changes in phosphate throughout the water column. Results obtained by this method are compared with estimates of carbon uptake using 14C made on the Fladen Ground during 1955 and 1956. There is good general agreement between the two methods but some differences in the vertical distribution.The results are also used to calculate filtering rates of phytoplankton and sinking rates of zooplankton, and to compare observed and predicted vertical distributions of chlorophyll.

Diel vertical distribution of fish larvae during the winter-mixing period in the Northwestern Mediterranean

2004 ◽  
Vol 61 (8) ◽  
pp. 1243-1252 ◽  
Author(s):  
A. Sabatés
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Fish Species ◽  
Fish Larvae ◽  
Distribution Patterns ◽  
Diel Variation ◽  
Surface Layers ◽  
Light Levels ◽  
Vertical Distributions ◽  
The Vertical Distribution

Abstract The vertical distributions of the larvae of shelf and oceanic fish species that spawn during the winter-mixing period in the Mediterranean are described from 22 vertically stratified plankton tows. Diel differences in the vertical distribution patterns in relation to physical data and potential prey abundance throughout the water column were examined. Even in absence of stratification, the larvae of the various fish species showed different patterns of vertical distribution and diel changes. The larvae of shelf-dwelling species were found in the surface layers, mainly above 50-m depth, and with some exceptions, with very little diel variation in depth distribution. Therefore, the vertical distribution of the larvae of these species coincided with the maximum concentrations of their potential food, nauplii and copepodite stages of copepods. The larvae of mesopelagic fishes showed deeper distributions in the water column and most of these species were located closer to the surface during the day than at night. Given the homogeneity of the physical characteristics throughout the water column, except for light, this behaviour may be determined not only by the higher concentration of prey in the surface layers but also by adequate light levels for feeding.

scholarly journals Optimal estimation of catch by the continuous underway fish egg sampler based on a model of the vertical distribution of American plaice (Hippoglossoides platessoides) eggs

2006 ◽  
Vol 64 (1) ◽  
pp. 18-30 ◽  
Author(s):  
P. Pepin ◽  
K. A. Curtis ◽  
P. V. R. Snelgrove ◽  
B. de Young ◽  
J. A. Helbig
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Vertical Profile ◽  
Negative Binomial ◽  
Optimal Estimation ◽  
Eddy Diffusivity ◽  
Model Parameters ◽  
Error Structure ◽  
The Vertical Distribution ◽  
Hippoglossoides Platessoides

Abstract Pepin, P., Curtis, K.A., Snelgrove, P.V.R., de Young, B., and Helbig, J.A. 2007. Optimal estimation of catch by the continous underway fish egg sampler based on a model of the vertical distribution of American plaice (Hippoglossoides platessoides) eggs – ICES Journal of Marine Science, 64, 18–30. We investigate how the vertical stratification of the water column (specifically density) affects predictions of the catch of American plaice eggs (Hipploglossoides platessoides) from a fixed-depth sampler [the continuous underway fish egg sampler (CUFES)] relative to the integrated abundance in the water column measured in bongo tows. A steady-state model of the vertical distribution of fish eggs coupled with a simple model of the vertical profile of eddy diffusivity (i.e. mixing) is applied. Key model parameters are estimated through optimization of a one-to-one relationship between predicted and observed catches fit, using a generalized linear model with a Poisson, negative binomial, or gamma error structure. The incorporation of data on the vertical structure of the water column significantly improved the ability to forecast CUFES catches when using Poisson or negative binomial error structure, but not using a gamma distribution. Optimal maximum likelihood parameter estimates for eddy diffusivity and egg buoyancy fell within the range of expected values. The degree of uncertainty in the parameterization of eddy diffusivity suggests, however, that greater understanding of the forces that determine the vertical profile of mixing is critical to achieving strong predictive capabilities. The inverse problem of predicting integrated abundance from CUFES catches did not benefit from the environmental-driven model because of the high uncertainty in the catches from the CUFES.

scholarly journals Vertical distribution of pre-settled sandeel (Ammodytes marinus) in the North Sea in relation to size and environmental variables

2003 ◽  
Vol 60 (6) ◽  
pp. 1342-1351 ◽  
Author(s):  
Henrik Jensen ◽  
Peter J Wright ◽  
Peter Munk
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
North Sea ◽  
Distribution Patterns ◽  
Food Concentration ◽  
The North ◽  
Vertical Distributions ◽  
The North Sea ◽  
Drift Trajectory ◽  
Vertical Positioning

Abstract Vertical distribution patterns of larval and juvenile sandeels were investigated at four locations in the North Sea. Sandeels between 6 and 65 mm were found to depths of 80 m, with vertical distributions dependent on both length and environmental factors. At one location with a stratified water column, the highest densities were found during the day in midwater where food concentration was also highest. In areas without marked vertical hydrographic gradients, larvae were relatively more abundant in surface waters during the day. At all locations, larvae of all sizes were generally more homogeneously distributed in the water column during night than during day. The extent of vertical migration, as measured by the standard deviation of the mean depth, increased generally with length. Gear avoidance was evident for larvae ≥20 mm. Catch efficiency generally depended on both length class and surface light intensity. A simulated drift pattern of larvae, based on ADCP current measurements from two locations, predicts that the horizontal drift trajectory would only be affected slightly by the vertical positioning of the larvae in the water column during the time of sampling. The implication of vertical migrations for dispersal of larvae away from the spawning grounds is discussed.

Vertical distribution of pelagial zooplankton in a middle-sized dimictic valley reservoir

Biologia ◽  
2006 ◽  
Vol 61 (2) ◽  
Author(s):  
Martina Hudcovicová ◽  
Marian Vranovsky
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Seasonal Changes ◽  
Thermal Gradient ◽  
Summer Temperature ◽  
Zooplankton Abundance ◽  
Invertebrate Predation ◽  
Chaoborus Flavicans ◽  
Daphnia Cucullata ◽  
The Vertical Distribution

AbstractOur observations indicate the vertical distribution of zooplankton and its seasonal changes in Dubník II reservoir (Slovakia) are determined mainly by the thermal regime of the reservoir, by transparency, and by fish and invertebrate predation. During periods of circulation, zooplankton vertical distribution in the whole water column was more homogeneous, whilst during summer temperature stratification zooplankton concentrated in the epilimnion — rotifers in higher layers than crustaceans. During summer stagnation a steep thermal gradient occurred at the boundary of the epi-and hypolimnion and low temperature and low dissolved oxygen in hypolimnion offered a refuge for Chaoborus flavicans larvae against fish, enabling coexistence of vertebrate and invertebrate predation. This evidence supports our previous findings concerning dominance of rotifers in zooplankton and representation of crustaceans by small-bodied species in the study reservoir. Steep thermal gradient and the presence of Chaoborus larvae caused very low zooplankton abundance in the lower part of the water column and a reduction of cladocerans refuges against fish to layers of thermocline or closely under thermocline where Daphnia cucullata and Daphnia parvula were found. Our previous assumptions about the high density of zooplanktivorous fish in Dubník II reservoir are supported by the fact that these small cladocerans are represented by smaller individuals in the upper layers and bigger individuals in deeper layers.

Vertical Distribution of Northern Shrimp (Pandalus borealis) Larvae in the Gulf of St Lawrence; Implications for Trophic Interactions and Transport

1994 ◽  
Vol 51 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Patrick Ouellet ◽  
Denis Lefaivre
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Suspended Particle ◽  
Stage I ◽  
Vertical Position ◽  
Pandalus Borealis ◽  
Northern Shrimp ◽  
Residual Transport ◽  
Larval Emergence ◽  
The Vertical Distribution

In the northwestern Gulf of St. Lawrence in spring 1987 and 1988, stage I and II northern shrimp (Pandalus borealis) larvae were concentrated in the upper (<30 m) layers above the permanent pycnocline and coincident with subsurface chlorophyll a and suspended particle concentration maxima; this was above other macrozooplankton taxa in the daytime. Shrimp larvae maintained their vertical position relative to the maximum density gradient in the water column in daytime but moved towards the surface at night. Estimation of larval residual transport (~66 km) during the first developmental stage (12 d) corresponded to the horizontal scale of patches of stage I shrimp larvae in the northwest sector of the Gulf. The result is consistent with the suggestion of localized and short-duration larval emergence in the sector. The direction of mass transport and current speed were similar throughout the upper layers of the water column; consequently, the direction and magnitude of larval shrimp transport were not dependent on their vertical position. We suggest that the vertical distribution maintained by shrimp larvae is a mechanism to ensure maximum food availability and to optimize development time in the stratified water of the northwestern Gulf of St. Lawrence.

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 Sinking microplastics in the water column: simulations in the Mediterranean Sea

Ocean Science ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. 431-453
Author(s):  
Rebeca de la Fuente ◽  
Gábor Drótos ◽  
Emilio Hernández-García ◽  
Cristóbal López ◽  
Erik van Sebille
Keyword(s):  
Vertical Distribution ◽  
Mediterranean Sea ◽  
Water Column ◽  
Large Scale ◽  
Circulation Model ◽  
Small Scale ◽  
The Mediterranean ◽  
Scale Turbulence ◽  
Non Gaussian ◽  
The Vertical Distribution

Abstract. We study the vertical dispersion and distribution of negatively buoyant rigid microplastics within a realistic circulation model of the Mediterranean sea. We first propose an equation describing their idealized dynamics. In that framework, we evaluate the importance of some relevant physical effects (inertia, Coriolis force, small-scale turbulence and variable seawater density), and we bound the relative error of simplifying the dynamics to a constant sinking velocity added to a large-scale velocity field. We then calculate the amount and vertical distribution of microplastic particles on the water column of the open ocean if their release from the sea surface is continuous at rates compatible with observations in the Mediterranean. The vertical distribution is found to be almost uniform with depth for the majority of our parameter range. Transient distributions from flash releases reveal a non-Gaussian character of the dispersion and various diffusion laws, both normal and anomalous. The origin of these behaviors is explored in terms of horizontal and vertical flow organization.

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.

SPIDERS (ARANEAE) IN CORN FIELDS IN QUEBEC

1988 ◽  
Vol 120 (2) ◽  
pp. 97-100 ◽  
Author(s):  
Louis Provencher ◽  
Daniel Coderre ◽  
Charles D. Dondale
Keyword(s):  
Species Composition ◽  
Vertical Distribution ◽  
Dominant Species ◽  
Spider Species ◽  
Vertical Distributions ◽  
Corn Fields ◽  
Corn Plants ◽  
Web Building ◽  
The Vertical Distribution

AbstractThe purpose of this study was to determine spider species composition and their temporal and vertical distributions in corn in southern Quebec. We sampled 30 corn plants weekly for 12 weeks from 9 July to 23 September in 1985. We found nine families, 14 genera, and 12 identifiable species. Web-building spiders were more abundant than hunting spiders. The dominant species was Tetragnatha laboriosa Hentz (Tetragnathidae). Web-builders were generally found under the ear of the plant, whereas the vertical distribution of hunting spiders was more even.

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