scholarly journals Near-bottom zooplankton in the continental shelf and upper slope of Heraklion Bay (Crete, Greece, Eastern Mediterranean): observations on vertical distribution patterns

2009 ◽  
Vol 31 (7) ◽  
pp. 753-762 ◽  
Author(s):  
P. Koulouri ◽  
C. Dounas ◽  
F. Radin ◽  
A. Eleftheriou
Keyword(s):  
Vertical Distribution ◽  
Continental Shelf ◽  
Eastern Mediterranean ◽  
Distribution Patterns ◽  
Upper Slope

scholarly journals FORAMINIFERA CHECK LIST AND THE MAIN SPECIES DISTRIBUTION IN THE AVEIRO LAGOON AND ADJACENT CONTINENTAL SHELF (PORTUGAL)

2019 ◽  
Vol 4 (1) ◽  
pp. 1-52 ◽  
Author(s):  
Maria Virgínia Alves Martins ◽  
Johann Hohenegger ◽  
Fabrizio Frontalini ◽  
Cristina Sequeira ◽  
Paulo Miranda ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Distribution Patterns ◽  
Check List ◽  
Outer Continental Shelf ◽  
Depth Functions ◽  
Main Species ◽  
Components Analysis ◽  
Foraminíferos Bentónicos ◽  
Aveiro Lagoon ◽  
Upper Slope

This work is based on a compilation of benthic foraminiferal data collected in the Aveiro Lagoon and in the adjacent continental shelf and upper slope (center of Portugal). It intends to provide an overall analysis from transitional to the outer continental shelf of the occurrence and distribution of species in living and to present updated taxonomic data and illustrations of most of the species found in the in the Aveiro Lagoon and in the adjacent continental shelf including in total assemblages. Cluster analysis (CA) and Principal Components Analysis (PCA) interpreted as depth functions allow us to identify the main species in different ecoenvironments and sectors of the study area. The most unusual living assemblage was documented in the lagoon inlet under very strong tidal currents activity, composed mostly by the following species (both in living and total assemblages): Rotaliammina concava, Lepidodeuterammina ochracea, Quinqueloculina seminula, Gavelinopsis praegeri, Paratrochammina haynesi, Remaneica helgolandica and Remaneicella gonzalezi. The distribution patterns of some Trochamminidae and Remaneicidae species whose ecology and distribution pattern are poorly known, have proved to be a marker of more or less hydrodynamic and stable/unstable environments in coastal and transitional marine environments. OCORRÊNCIA DE FORAMINÍFEROS E DISTRIBUIÇÃO DAS PRINCIPAIS ESPÉCIES NA LAGOA DE AVEIRO E NA PLATAFORMA CONTINENTAL ADJACENTE (PORTUGAL)ResumoEste trabalho baseia-se numa compilação de dados foraminíferos bentónicos recolhidos na Laguna de Aveiro e na plataforma continental adjacente (centro de Portugal). Pretende efetuar uma análise geral da distribuição de espécies nas associações vivas e totais (vivas e mortas) na área de estudo, em função da profundidade. Pretende ainda apresentar dados taxonómicos e ilustrações da maioria das espécies encontradas na Laguna de Aveiro e na plataforma continental adjacente. A análise de agrupamento (CA) e a análise de componentes principais (PCA), em função da profundidade, permitem identificar as principais espécies em diferentes ecossistemas e setores da área de estudo. A associação viva mais invulgar foi encontrada na embocadura da Laguna de Aveiro, um ambiente sujeito a forte corrente de maré. Essa associação era composta principalmente pelas seguintes espécies (na associação viva e total): Rotaliammina concava, Lepidodeuterammina ochracea, Quinqueloculina seminula, Gavelinopsis praegeri, Paratrochammina haynesi, Remaneica helgolandica and Remaneicella gonzalezi. Os padrões de distribuição de algumas espécies de Trochamminidae e Remaneicidae, cuja ecologia e padrão de distribuição são pouco conhecidos, mostraram ser um marcador de ambientes mais ou menos hidrodinâmicos e de estabilidade/instabilidade do substrato em ambientes marinhos costeiros e de transição. Palavras-chave: Ecologia. Taxonomia. Imagens digitais. Análise Estatística. Ambientes Transicionais e Costeiros Marinhos.

scholarly journals Distribution patterns of Recent pteropods in surface sediments of the western continental shelf of India

2005 ◽  
Vol 24 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Arun Deo Singh ◽  
Neelakantan Ravindran Nisha ◽  
Thadickal Viswanathan Joydas
Keyword(s):  
Continental Shelf ◽  
Surface Sediments ◽  
Salinity Gradient ◽  
Distribution Patterns ◽  
Qualitative And Quantitative ◽  
Profound Influence ◽  
Minimum Zone ◽  
Quantitative Analyses ◽  
Oxygen Minimum ◽  
Upper Slope

Abstract. This paper is the first contribution to the knowledge of pteropods in surficial sediments of the entire western continental shelf of India. Both qualitative and quantitative analyses of pteropod assemblages were carried out on 50 coarse fractions (>125 μm) of topmost portions of grab samples recovered along 12 transects covering the inner shelf to the upper slope (30–200 m water depths). The distribution of eight significant species was mapped. The resultant maps were correlated with the bathymetric, hydrographic and aragonite preservation conditions in the investigated area. This study reveals a bathymetric control over the distribution of Limacina inflata, Creseis acicula and Creseis chierchiae across the shelf. Furthermore, a marked difference in vertical salinity gradient from south to north along the shelf appears to have a profound influence on the abundance of these species. The pteropod shells in sediments of the northern offshore region with anoxic bottom conditions are generally well preserved, unlike the southern region, where oxygen concentration of the bottom water is relatively high enough to cause dissolution or even elimination of many shells of the most susceptible pteropods like C. acicula and C. chierchiae. The variation in the intensity of the oxygen minimum zone along the western continental shelf of India has significant influence upon the distribution pattern of Clio convexa.

scholarly journals Disentangling relationships among eastern Mediterranean Cymbalaria including description of a novel species from the southern Peloponnese (Greece)

2021 ◽  
Vol 307 (2) ◽  
Author(s):  
Pau Carnicero ◽  
Núria Garcia-Jacas ◽  
Llorenç Sáez ◽  
Theophanis Constantinidis ◽  
Mercè Galbany-Casals
Keyword(s):  
Eastern Mediterranean ◽  
Phylogenetic Analyses ◽  
Taxonomic Revision ◽  
Distribution Patterns ◽  
Morphological Characters ◽  
Molecular Data ◽  
Morphological Data ◽  
Long Distance ◽  
Aegean Islands ◽  
Molecular Phylogenetic

AbstractThe eastern Mediterranean basin hosts a remarkably high plant diversity. Historical connections between currently isolated areas across the Aegean region and long-distance dispersal events have been invoked to explain current distribution patterns of species. According to most recent treatments, at least two Cymbalaria species occur in this area, Cymbalaria microcalyx and C. longipes. The former comprises several intraspecific taxa, treated at different ranks by different authors based on morphological data, evidencing the need of a taxonomic revision. Additionally, some populations of C. microcalyx show exclusive morphological characters that do not match any described taxon. Here, we aim to shed light on the systematics of eastern Mediterranean Cymbalaria and to propose a classification informed by various sources of evidence. We performed molecular phylogenetic analyses using ITS, 3’ETS, ndhF and rpl32-trnL sequences and estimated the ploidy level of some taxa performing relative genome size measures. Molecular data combined with morphology support the division of traditionally delimited C. microcalyx into C. acutiloba, C. microcalyx and C. minor, corresponding to well-delimited nrDNA lineages. Furthermore, we propose to combine C. microcalyx subsp. paradoxa at the species level. A group of specimens previously thought to belong to Cymbalaria microcalyx constitute a well-defined phylogenetic and morphological entity and are described here as a new species, Cymbalaria spetae. Cymbalaria longipes is non-monophyletic, but characterized by being glabrous and diploid, unlike other eastern species. The nrDNA data suggest at least two dispersals from the mainland to the Aegean Islands, potentially facilitated by marine regressions.

Diel vertical distribution of early marine phase juvenile pink salmon (Oncorhynchus gorbuscha) and behaviour when exposed to salmon louse (Lepeophtheirus salmonis)

2011 ◽  
Vol 89 (9) ◽  
pp. 796-807 ◽  
Author(s):  
S. Tang ◽  
A.G. Lewis ◽  
M. Sackville ◽  
L. Nendick ◽  
C. DiBacco ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Pink Salmon ◽  
Distribution Patterns ◽  
Oncorhynchus Gorbuscha ◽  
Lepeophtheirus Salmonis ◽  
Night Time ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Salmon Louse ◽  
Seawater Acclimation

We observed diel vertical migration patterns in juvenile pink salmon ( Oncorhynchus gorbuscha (Walbaum, 1792)) and tested the hypothesis that fish behaviour is altered by exposure to sea lice copepodids. Experiments involved replicated field deployments of a large (9 m) plankton column, which provided a vertical distribution enclosure under natural light and salinity conditions. Diel vertical distributions of juvenile pink salmon were observed during the first 3 weeks of seawater acclimation in both the presence and the absence of the ectoparasitic salmon louse ( Lepeophtheirus salmonis (Krøyer, 1838)). Immediately upon entering seawater, juvenile pink salmon preferred the top 1 m of the water column, but they moved significantly deeper down the vertical water column as seawater acclimation time increased. A significant diel migration pattern was observed, which involved a preference for the surface at night-time, compared with daytime. When fish in the column were exposed to L. salmonis copepodids for 3 h, 43%–62% of fish became infected, fish expanded their vertical distribution range, and significant changes in vertical distribution patterns were observed.

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