Spatial Distribution of Plankton in Enclosures of Three Sizes

1984 ◽  
Vol 41 (7) ◽  
pp. 1048-1054 ◽  
Author(s):  
G. L. Stephenson ◽  
P. Hamilton ◽  
N. K. Kaushik ◽  
J. B. Robinson ◽  
K. R. Solomon
Keyword(s):  
Spatial Distribution ◽  
Horizontal Distribution ◽  
Individual Species ◽  
Population Estimates ◽  
Edge Zone ◽  
Southern Ontario ◽  
Zooplankton Population ◽  
Mesotrophic Lake ◽  
Definition Of ◽  
Sampling Times

The horizontal distribution of plankton was studied in large (1000 m3, 16 m diameter, 5 m deep), medium (5 × 5 × 5 m deep) and small (2 × 2 × 5 m deep) enclosures in a 10.3-ha mesotrophic lake in southern Ontario. Zooplankton population estimates from samples collected along distance gradients in the small and medium enclosures varied slightly but no consistent patterned distribution was present. However, the large enclosures possessed a distinctive edge zone that extended about 1.0 m from the walls. On two of the three sampling times there were significantly more macrozooplankton and/or fewer microzooplankton in the edge zone. However, on no occasion were there fewer macroplankton or more microzooplankton in the edge zone. Although macrozooplankton, as a group, may be significantly more numerous in the edge zone (P ≤ 0.05), individual species within this group exhibited both positive and negative responses. There was no defined edge zone in any enclosure with respect to phytoplankton density or biomass. Definition of the spatial distribution of organisms is essential to maximize precision of population estimates when using enclosure systems for ecotoxicological studies.

scholarly journals DIVERSIDADE E DISTRIBUIÇÃO ESPACIAL DE BROMELIÁCEAS EPIFÍTICAS DO ALTÍSSIMO RIO TIBAGI – PARANÁ – BRASIL

FLORESTA ◽  
2010 ◽  
Vol 40 (1) ◽  
Author(s):  
Annete Bonnet ◽  
Gustavo Ribas Curcio ◽  
Franklin Galvão ◽  
Carina Kozera
Keyword(s):  
Spatial Distribution ◽  
River Estuary ◽  
Horizontal Distribution ◽  
Variable Number ◽  
Climatic Factor ◽  
Atmospheric Humidity ◽  
Floristic Survey ◽  
Microclimatic Conditions ◽  
Definition Of ◽  
Epiphytic Bromeliads

O presente estudo teve como objetivo caracterizar a diversidade e a distribuição espacial das bromeliáceas epifíticas na região do altíssimo rio Tibagi, considerando os fatores geomorfológicos, pedológicos, climáticos e vegetacionais. A avaliação fitossociológica das bromeliáceas foi realizada mediante instalação de parcelas em número variável nas três áreas de estudo. O levantamento florístico foi complementado por observações nas áreas adjacentes às parcelas, respeitando a compartimentação geomorfológica, pedológica e vegetacional. Foram registradas onze espécies de bromeliáceas no total, tendo sido sete delas observadas na área da cabeceira do rio Tibagi, oito no cânion e nove na floresta da foz do rio Bugio. A riqueza foi relacionada, principalmente, com as condições macro e microclimáticas. A umidade fornecida pelas nuvens e chuvas formadas na cuesta do segundo planalto, assim como, em microescala, a umidade atmosférica gerada pelas cachoeiras existentes no cânion e originada da evaporação da água dos Organossolos, é o fator climático fundamental na definição dos padrões encontrados. Considerando a distribuição horizontal das espécies, a diminuição de bromeliáceas da porção mais próxima ao canal para a mais distante está atrelada ao gradiente microclimático, formado pela redução em umidade relativa associada à diminuição em luminosidade. Palavras-chave: Bromeliáceas; distribuição espacial; umidade; rio Tibagi.   Abstract Diversity and spatial distribution of epiphytic bromeliads of the high Tibagi river, Paraná, Brazil. The present study aims to characterize the diversity and the spatial distribution of epiphytic bromeliads on the region of the high Tibagi river, considering geomorphologic, pedologic, climatic and vegetacional factors. The phytossociological evaluation was achieved with installation of variable number of plots in the three study areas. The floristic survey was complemented by observations in adjacent areas, respecting the geomorphologic, pedologic and vegetacional compartimentation. Eleven bromeliad species were found in total, being seven species in headwater of Tibagi river area, eight in canyon area and nine in the forest of the Bugio river estuary. The richness was related, mainly, with the macro and microclimatic conditions. The humidity supplied by clouds and rains formed in the cuesta of the second platean, as will as, in microscale, the atmospheric humidity generated by canyons waterfalls and originated of the Organossolos water, is the fundamental climatic factor in the definition of the found standards. Considering the species horizontal distribution, the bromeliads reduction of the closer portion to the stream to the most distant ones is related to the microclimatic gradient, formed by the decreasing of relative humidity associated with luminosity.Keywords: Bromeliads; spatial distribution; humidity; Tibagi river.

scholarly journals Advanced 3D Cell Culture Techniques in Micro-Bioreactors, Part II: Systems and Applications

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 21
Author(s):  
Brigitte Altmann ◽  
Christoph Grün ◽  
Cordula Nies ◽  
Eric Gottwald
Keyword(s):  
Cell Culture ◽  
Spatial Distribution ◽  
3D Cell Culture ◽  
Research Area ◽  
Cell Culture Techniques ◽  
Culture Techniques ◽  
Cell Functions ◽  
Matrix Interactions ◽  
Definition Of ◽  
Extracellular Matrix Interactions

In this second part of our systematic review on the research area of 3D cell culture in micro-bioreactors we give a detailed description of the published work with regard to the existing micro-bioreactor types and their applications, and highlight important results gathered with the respective systems. As an interesting detail, we found that micro-bioreactors have already been used in SARS-CoV research prior to the SARS-CoV2 pandemic. As our literature research revealed a variety of 3D cell culture configurations in the examined bioreactor systems, we defined in review part one “complexity levels” by means of the corresponding 3D cell culture techniques applied in the systems. The definition of the complexity is thereby based on the knowledge that the spatial distribution of cell-extracellular matrix interactions and the spatial distribution of homologous and heterologous cell–cell contacts play an important role in modulating cell functions. Because at least one of these parameters can be assigned to the 3D cell culture techniques discussed in the present review, we structured the studies according to the complexity levels applied in the MBR systems.

scholarly journals Defining and Characterising Clusters in Palaeolithic Sites: a Review of Methods and Constraints

2021 ◽  
Author(s):  
Laura Sánchez-Romero ◽  
Alfonso Benito-Calvo ◽  
Joseba Rios-Garaizar
Keyword(s):  
Distribution Patterns ◽  
Horizontal Distribution ◽  
Spatial Studies ◽  
Innovative Methods ◽  
General Terms ◽  
Fabric Analysis ◽  
Gis Tools ◽  
Definition Of ◽  
Intentional Activities ◽  
Statistical Criteria

AbstractSpatial analysis studies in Palaeolithic archaeology arise as indispensable research tools for understanding archaeopalaeontological sites. In general terms, spatial studies have been specialised in the description of the distribution of materials and in the definition of accumulation areas, with the aim of distinguishing intentional activities or studying postdepositional processes. In recent decades, the development of GIS tools has enabled huge strides forward in the field of spatial archaeology research, such as spatial inferential statistics. These tools are particularly useful in the identification and location of clustering from statistical criteria, facilitating the subsequent analysis of accumulations through other archaeological, taphonomic and spatial techniques, such as fabric analysis or directional distribution. The cluster analysis, and its contextualisation considering all the archaeological and stratigraphical variables, allows the inference of some of the processes and factors that could have taken part in the accumulation of materials, as well as assessing how this affected the composition and preservation of the archaeological assemblage. The present article reviews the more traditional and innovative methods for studying horizontal distribution patterns and the objective definition of clusters, highlighting the parameters, uses and limitations of these techniques. We present an application of these methods to different Palaeolithic sites, going through different scenarios, such as location (open-air vs. cave), context, scale (large vs. small area), excavation methodology and spatial record methods.

Entomopathogenic nematode (Heterorhabditidae and Steinernematidae) spatial distribution in turfgrass

Parasitology ◽  
1996 ◽  
Vol 113 (5) ◽  
pp. 473-482 ◽  
Author(s):  
J. F. Campbell ◽  
E. Lewis ◽  
F. Yoder ◽  
R. Gaugler
Keyword(s):  
Spatial Distribution ◽  
Vertical Distribution ◽  
Entomopathogenic Nematodes ◽  
Entomopathogenic Nematode ◽  
Soil Surface ◽  
Nematode Species ◽  
Horizontal Distribution ◽  
Steinernema Carpocapsae ◽  
Foraging Strategies ◽  
Temporal And Spatial Distribution

SUMMARYUnderstanding the temporal and spatial distribution of entomopathogenic nematodes is essential for determining the role of these insect parasites in soil communities and ultimately for their use in suppression of pest insect populations. We measured the vertical and horizontal distribution of endemic populations of entomopathogenic nematodes (Steinernema carpocapsae and Heterorhabditis bacteriophord) in turfgrass. Vertical distribution was determined by taking soil cores every 3 h from 05.00 to 23.00 h, over 4 days, and dividing the cores into 8, 1 cm deep sections. Steinernema carpocapsae was recovered primarily near the soil surface: 50% of positive sections were recovered in the thatch or first 1 cm of soil. S. carpocapsae recovery was lower during the middle of the day and none were recovered in the upper section. H. bacteriophora was recovered uniformly throughout the top 8 cm of soil and its vertical distribution did not change over the course of the day. Horizontal distribution was measured as the number of nematodes recovered from cores taken from 12 randomly selected 0·3 × 0·8 m sections from within four 15·3 × 15·3 m plots. Samples were collected biweekly over a 9-month period. H. bacteriophora had a patchier distribution than S. carpocapsae and both nematode species had more patchy distributions then their potential hosts. Our results support the hypothesis that these two species of nematode utilize different foraging strategies; S. carpocapsae primarily a surface adapted ambusher and H. bacteriophora as a cruise forager.

scholarly journals The spatial distribution of shallow-water (<150 m) black corals (Cnidaria: Antipatharia) in the Hawaiian Archipelago

2015 ◽  
Vol 8 ◽  
Author(s):  
Daniel Wagner
Keyword(s):  
Spatial Distribution ◽  
Coral Species ◽  
Individual Species ◽  
Hawaiian Archipelago ◽  
Black Coral ◽  
Ecological Features ◽  
Black Corals ◽  
Single Category ◽  
The Mean ◽  
Hard Substrates

The Hawaiian Archipelago contains some of the best surveyed black coral populations on the globe; however, most previous surveys have grouped all black coral species into a single category. As a result, the unique ecological features of individual species have not been identified. This study mapped the spatial distribution of eight antipatharian species (Antipathes griggi,Antipathes grandis,Cirrhipathescf.anguina,Stichopathes echinulata,Stichopathes?sp.,Aphanipathes verticillata,Acanthopathes undulataandMyriopathescf.ulex) found in shallow-waters (&lt;150 m) along the Hawaiian Archipelago, and compared data on substrate type, depth and temperature among species. All black coral species were exclusively recorded on hard substrates and were generally widely distributed along the Hawaiian Islands. Additionally, antipatharian species were found at overlapping depths and temperatures, although there were significant differences in the mean depths and temperatures between most species. In cases where species did not have significant differences in mean depths, the overlapping species had different colony and polyp morphologies, which may serve to minimize competition by allowing species to grow most efficiently under particular current regimes. This study represents one of the first to map the spatial distribution of sympatric antipatharian species, and indicates that individual species exploit unique environments in terms of depth and temperature or have unique morphologies to avoid overlap.

scholarly journals Vegetation richness, height, coverage and spatial distribution mediate grasshopper abundance in the upper reaches of Heihe River, China

2017 ◽  
Author(s):  
Lili Li ◽  
Chengzhang Zhao ◽  
Tingjun Zhang ◽  
dawei wang ◽  
yuxing li ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Distribution Pattern ◽  
Species Interactions ◽  
Horizontal Distribution ◽  
Heihe River ◽  
Vegetation Community ◽  
Altitude Gradient ◽  
Geostatistical Methods ◽  
Relationship Of ◽  
The Relationship

Species interactions are often context-dependent and complex, such as the grasshopper community and phytoecommunity. The adoption of grasshopper abundance and vegetation community was determined by topographical heterogeneity. However, it remains vague about how vegetation community, such as coverage abundance and height, influence the spatial distribution pattern of grasshopper abundance at the altitude gradient. Using Geostatistical methods in natural grassland of the upper reaches of Heihe River to quantitatively study the relationship of spatial correlation. A 3 years investigation was shown that 3149 grasshoppers were collected, belonging to 3 families, 10 genera, and 13 species. The semivariable function of grasshopper abundance and vegetation community followed a nonlinear model. Meanwhile, horizontal distribution of two communities was a clear flaky and plaque distribution pattern, especially at the altitude gradient. The abundance of grasshoppers is opposite to the height and coverage of vegetation and the overall followability of coverage, while the local following is consistent. Such as grasshopper abundance, the above 2750m sample with the opposite trend, the following areas are consistent. Finally, grasshoppers have the different choice on different vegetation characteristics in different directions, formed of specific trend characteristics; and the spatial distribution trend is different even with the same community indicators, formed of embedded striped patches structure.

scholarly journals Analysis spatial distribution trees in forest stands

2006 ◽  
pp. 165-176 ◽  
Author(s):  
Branko Stajic ◽  
Milivoj Vuckovic
Keyword(s):  
Spatial Distribution ◽  
Growth Factors ◽  
Stand Structure ◽  
Horizontal Distribution ◽  
Pure Stand ◽  
Statistical Distributions ◽  
Dispersion Index ◽  
Study Results ◽  
Growth Space ◽  
Growth Development

The analyses of the horizontal distribution of trees have not been used in the research of stand structure in Serbia?s forestry to date. Taking into account the high economic and ecological applicability of such information, this paper deals with the numerical description of the form of spatial distribution of trees. The applied methods are the so-called methods of statistical distributions and dispersion index. The study results in the all-aged mixed stand of fir and beech and in the mature pure stand of fir on the mountain Goc show that all trees together, but also the trees per species, are predominantly randomly distributed in space, with the tendencies towards a weaker or stronger aggregation or uniformity. Based on the identified spatial distribution of trees, it can be concluded that in the greater part of the study stands the environment is homogeneous and the basic conditions of tree growth are uniform. This points to the fact that real assessment of growth development and the competition of fir and beech, due to the identified absence of a marked competition for the basic growth factors, emphasizes, primarily, the quantification of the competition for growth space. .

Spatial patterns

2018 ◽  
Author(s):  
Philip James
Keyword(s):  
Spatial Distribution ◽  
Urban Environment ◽  
Distribution Patterns ◽  
Intermediate Disturbance Hypothesis ◽  
Urban Environments ◽  
Individual Species ◽  
Urban Forms ◽  
Intermediate Disturbance ◽  
Urban Rural ◽  
Disturbance Hypothesis

In this chapter, the discussion focuses on the spatial variation of species within urban environment. Studies on urban–rural gradients are discussed. These are studies along gradients of disturbance and environmental stress. The extreme heterogeneity of urban environments, where contrasting urban forms are juxtaposed, is recognized as an issue in drawing generalities. Despite this, some limited generalities in the patterns of species richness and density can be detected. The intermediate disturbance hypothesis is discussed and its limitations identified. Examples are presented from a number of taxa where different spatial distribution patterns are observed. There is also a brief consideration of r- and K-selected species and of urban avoiders and adaptors and how their distributions are affected by urban environments. While it is possible to make general statements regarding the distribution of biodiversity across an urban environment, considerable variations exist in terms of individual species.

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