scholarly journals Euphausiids (Euphausiacea) off Malpelo Island, Colombian Eastern Tropical Pacific

2019 ◽  
Vol 67 (1) ◽  
Author(s):  
Marisol Rivera Gómez ◽  
Alan Giraldo
Keyword(s):  
Vertical Distribution ◽  
Abundant Species ◽  
Superficial Layer ◽  
Taxonomic Composition ◽  
Distribution Models ◽  
Linear Distribution ◽  
Opposite Pattern ◽  
Pelagic Environment ◽  
Distribution Index ◽  
Malpelo Island

Euphausiids migrate vertically in the water column as part of their diel cycle. These migrations make them a key element in the biological pump of the pelagic environment. We took stratified zooplankton samples (0-50, 50-100, and 100-150 m) during the Pacífico-ERFEN campaign in September 2012 to evaluate the vertical distribution of euphausiids around Malpelo Island (3.8 - 4.2 N, 81.4 - 81.8 W). A total of 10 species belonging to four genera were identified. Euphausia diomedeae was the most abundant species in the 0-50 and 100-150 m layers, whereas E. distinguenda was the most abundant species in the 50-100 m layer. Based on quasi-Poisson generalized linear distribution models we found that abundance in the 50-100 m layer was significantly higher than in the 100-150 m layer (t = 3.05, p < 0.05). There were no significant differences associated with sampling hour (diurnal/nocturnal) (t = 0.07, p = 0.94). We calculated a vertical distribution index (VDI) based on abundance, which showed that euphausiid species were concentrated in the 50-100 m layer during day and night. Calyptopis larvae dominated in abundance at all depth layers, followed by furcilia larvae, juveniles and adults. The abundance of the latter increased gradually from the most superficial layer to the deepest layer, whereas juveniles showed the opposite pattern. This is the first study to describe the taxonomic composition, and vertical and spatial distribution of euphausiids associated with Malpelo Island, Colombian Pacific.

scholarly journals CARACTERÍSTICAS OCEANOGRÁFICAS EN LA ISLA MALPELO Y SU RELACIÓN CON LA CUENCA OCEÁNICA DEL PACÍFICO COLOMBIANO

2016 ◽  
Vol 40 ◽  
Author(s):  
Efraín Rodríguez Rubio ◽  
Alan Giraldo
Keyword(s):  
Water Mass ◽  
Terrestrial Ecosystems ◽  
In Situ Data ◽  
Pelagic Environment ◽  
Shallow Subtidal ◽  
Oceanographic Data ◽  
Malpelo Island ◽  
Physical And Chemical ◽  
Colombian Pacific

Malpelo Island forms the insular ecoregion of the Colombian Pacific, and is composed by a mosaic of terrestrial ecosystems, and unique coastal and shallow subtidal systems. Considering its insular nature, the oceanographic features of this locality are expected to be related with the physical and chemical dynamics of the Eastern Tropical Pacific (ETP) and be modulated by the regional dynamic of the Colombian Pacific Oceanic Basin (COPC in Spanish). In this work, in situ data was used to describe the thermohaline conditions in the water column in Malpelo Island and identify key water mass during the two contrasting hydro-meteorological periods of the COPC. Furthermore, we analyzed the thermal and haline variability in the COPC and defined the surface geostrophic flow from in situ oceanographic data during the same time in order to evaluate its effect on the oceanographic conditions in the pelagic environment off Malpelo Island.

Synchronous blooms of the coccolithophore Emiliania huxleyi and three dinoflagellates in the Dardanelles (Turkish Straits System)

2008 ◽  
Vol 88 (3) ◽  
pp. 433-441 ◽  
Author(s):  
Muhammet Turkoglu
Keyword(s):  
Thermal Stratification ◽  
Algal Bloom ◽  
Environmental Parameters ◽  
Abundant Species ◽  
Superficial Layer ◽  
Emiliania Huxleyi ◽  
Sea Of Marmara ◽  
Prorocentrum Micans ◽  
Ceratium Furca ◽  
The Vertical Distribution

This study focuses on the synchronous blooms of the coccolithophore Emiliania huxleyi and three dinoflagellates Prorocentrum micans, Ceratium furca var. furca and Ceratium fusus var. seta observed between 7 June and 11 July 2003 in the Dardanelles. An analysis of the vertical distribution of the E. huxleyi population size with respect to various environmental parameters was discussed. Additionally, inorganic nutrients and phytoplankton interactions were investigated in relation to the bloom conditions and hydrography of the Dardanelles. The algal bloom started in nearby Izmit Bay (eastern end of the Sea of Marmara) in early June, then quickly spread through the Sea of Marmara and continued until mid-July. Thermal stratification was observed between different water masses at the time of sampling. During the bloom period, cell density of E. huxleyi ranged from 3.58 × 107 to 2.55 × 108 cells l−1 in the superficial layer. Prorocentrum micans was the second most-abundant species and the cell numbers ranged from 1.0 × 106 cells l−1 to 3.3 × 106 cells l−1. Other abundant species in this area included C. furca var. furca and C. fusus var. seta.

scholarly journals Composition and diversity of anurans in the largest conservation unit in Pampa biome, Brazil

2016 ◽  
Vol 16 (2) ◽  
Author(s):  
Ana Maria Rigon Bolzan ◽  
Suélen Alves Saccol ◽  
Tiago Gomes dos Santos
Keyword(s):  
South America ◽  
Geographic Distance ◽  
Abundant Species ◽  
Taxonomic Composition ◽  
Reproductive Modes ◽  
Pampa Biome ◽  
Conservation Actions ◽  
Scientific Collections ◽  
Bodies Of Water ◽  
Initial Knowledge

Grassy biomes occupy about 20% of the earth's surface, and are characteristic of northern Australia, Africa and South America, being biodiversity in these environments poorly understood. The Área de Proteção Ambiental (APA) do Ibirapuitã includes areas with the best-preserved grassland areas in the Pampa biome in Rio Grande do Sul state, Brazil. This study aimed to determine anuran species richness, abundance, constancy of occurrence, and reproductive modes, and to compare the taxonomic composition in the APA with other localities within the grassland areas of the southernmost of South America. We collected frogs from September to November 2012 and in November 2013 by sampling of reproductive sites. We also examined specimens deposited in herpetological collections. In total, 32 frog species were identified from the combination of larval and adult sampling and analysis of specimens deposited in scientific collections. The registered anurofauna is typical of grassland areas, with at least 10% restricted to the subtropical region of South America and at least two species considered endangered in state and global scales. The most abundant species was Pseudopaludicola falcipes and Hypsiboas pulchellus was the species most frequently found among sites. Five reproductive modes were recorded, and the most common mode consists of development of exotrophic tadpole and deposition in to lentic bodies of water (57.5%). Cluster analysis of 16 communities representing grassland locations presented five groups with more than 50% similarity, whose structure was influenced by geographic distance but can be partially interpreted by regional peculiarities (e.g. height and phytophysiognomies). Our results consist of initial knowledge base on the anurofauna of APA do Ibirapuitã, supporting recommendations for future conservation actions to APA and also for the grassland biomes, which are increasingly threatened by human activities.

Studies on West African Forest Mosquitos

1949 ◽  
Vol 40 (3) ◽  
pp. 387-402 ◽  
Author(s):  
P. F. Mattingly
Keyword(s):  
Vertical Distribution ◽  
Field Studies ◽  
Abundant Species ◽  
Maximum Activity ◽  
General Level ◽  
Breeding Cycle ◽  
Level Of Activity ◽  
Relationship Of ◽  
The Vertical Distribution ◽  
Similar Kind

The present paper is the second of two dealing with field studies carried out near Lagos, Nigeria. The first paper covered four of the most abundant species encountered and the second is concerned with the remaining forty-eight. These are listed and the data relating to the thirty-eight least abundant, with the exception of two which were taken as males only, are given in tabular form. The other ten are dealt with at greater length. Males of twenty-six species were taken and in the case of three of these species they were so abundant as to create the impression that a swarming activity was involved. In the case of the ten more abundant species seasonal distribution curves are given based on average monthly catches and an attempt is made to relate these to variations in rainfall. The biting curves which are next discussed show a greater variety of types than those described in the first paper. In general, they are characterised by a fairly sharp peak associated with morning or evening twilight, but some have a more or less pronounced peak at both ends of the cycle and so correspond to the “eo-crepuscular” type of Haddow (1945). Anopheles paludis, like Taeniorhynchus africanus (described in the first paper) has an ill-defined period of maximum activity during the middle of the night. The necessity of sub-dividing the figures in order to obtain a picture of the vertical distribution of the various species led in one or two cases to anomalous results, but in general a clear and fairly convincing picture was obtained. None of the species dealt with in the present paper was sufficiently abundant to afford reliable data on hourly variations in vertical distribution. In the general discussion, which embodies such inferences as it has seemed permissible to draw from the data, attention is drawn to the fact that the so-called “biting cycle” does not, in all likelihood, depend exclusively on variations in the urge to bite, but is more probably an expression of cyclical changes taking place in the general level of activity of the mosquito. The possible relationship of such changes to changes of a similar kind in the physical environment is discussed, and it is pointed out that intrinsic rhythms in the mosquito, perhaps related to the breeding cycle, may also be involved. Some data are presented which, while partly explained by the presence of a sibling species, may also indicate an interrelationship between the breeding cycle and vertical distribution.

Effects of seasonality on drosophilids (Insecta, Diptera) in the northern part of the Atlantic Forest, Brazil

2017 ◽  
Vol 107 (5) ◽  
pp. 634-644 ◽  
Author(s):  
R.D. Coutinho-Silva ◽  
M.A. Montes ◽  
G.F. Oliveira ◽  
F.G. de Carvalho-Neto ◽  
C. Rohde ◽  
...  
Keyword(s):  
Exotic Species ◽  
Atlantic Forest ◽  
Seasonal Pattern ◽  
Abundant Species ◽  
Neotropical Region ◽  
Dry Season ◽  
Opposite Pattern ◽  
Tropical Regions ◽  
Rainy Period ◽  
Northern Atlantic

AbstractSeasonality is an important aspect associated with population dynamic and structure of tropical insect assemblages. This study evaluated the effects of seasonality on abundance, richness, diversity and composition of an insect group, drosophilids, including species native to the Neotropical region and exotic ones. Three preserved fragments of the northern Atlantic Forest were surveyed, where temperatures are above 20 °C throughout the year and rainfall regimes define two seasons (dry and rainy). As opposed to other studies about arthropods in tropical regions, we observed that abundance of drosophilids was significantly higher in the dry season, possibly due to biological aspects and the colonization strategy adopted by the exotic species in these environments. Contrarily to abundance, we did not observe a seasonal pattern for richness. As for other parts of the Atlantic Forest, the most representative Neotropical species (Drosophila willistoni, D. sturtevanti, D. paulistorum and D. prosaltans) were significantly more abundant in the rainy season. Among the most abundant exotic species, D. malerkotliana, Zaprionus indianus and Scaptodrosophila latifasciaeformis were more importantly represented the dry season, while D. simulans was more abundant in the rainy period. The seasonality patterns exhibited by the most abundant species were compared to findings published in other studies. Our results indicate that exotic species were significantly more abundant in the dry season, while native ones exhibited an opposite pattern.

scholarly journals Salp grazing:effects on phytoplankton abundance, vertical distribution and taxonomic composition in a coastal habitat

1995 ◽  
Vol 126 ◽  
pp. 267-283 ◽  
Author(s):  
JR Zeldis ◽  
CS Davis ◽  
MR James ◽  
SL Ballara ◽  
WE Booth ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Taxonomic Composition ◽  
Phytoplankton Abundance ◽  
Coastal Habitat

scholarly journals A quantitative review of abundance-based species distribution models

2021 ◽  
Author(s):  
Conor Waldock ◽  
Rick D. Stuart-Smith ◽  
Camille Albouy ◽  
William W. L. Cheung ◽  
Graham J. Edgar ◽  
...  
Keyword(s):  
Species Distribution ◽  
Species Distribution Models ◽  
Species Abundance ◽  
Abundant Species ◽  
Spatial Modelling ◽  
Ecosystem Functions ◽  
Distribution Models ◽  
Abundance Patterns ◽  
Reef Fish Species ◽  
Model Training

The contributions of species to ecosystem functions or services depend not only on their presence in a given community, but also on their local abundance. Progress in predictive spatial modelling has largely focused on species occurrence, rather than abundance. As such, limited guidance exists on the most reliable methods to explain and predict spatial variation in abundance. We analysed the performance of 68 abundance-based species distribution models fitted to 800,000 standardised abundance records for more than 800 terrestrial bird and reef fish species. We found high heterogeneity in performance of abundance-based models. While many models performed poorly, a subset of models consistently reconstructed range-wide abundance patterns. The best predictions were obtained using random forests for frequently encountered and abundant species, and for predictions within the same environmental domain as model calibration. Extending predictions of species abundance outside of the environmental conditions used in model training generated poor predictions. Thus, interpolation of abundances between observations can help improve understanding of spatial abundance patterns, but extrapolated predictions of abundance, e.g. under climate change, have a much greater uncertainty. Our synthesis provides a roadmap for modelling abundance patterns, a key property of species' distributions that underpins theoretical and applied questions in ecology and conservation.

scholarly journals DIVERSIDAD, ABUNDANCIA Y AMENAZAS DE LOS OCTOCORALES DE LA ISLA MALPELO, PACÍFICO ORIENTAL TROPICAL, COLOMBIA

2016 ◽  
Vol 40 ◽  
Author(s):  
Juan A. Sánchez ◽  
Carlos E. Gómez ◽  
Dairo Escobar ◽  
Luisa F. Dueñas
Keyword(s):  
Invasive Species ◽  
Transition Zone ◽  
High Mortality ◽  
Abundant Species ◽  
Disease Prevalence ◽  
Fungal Diseases ◽  
Frequency Of Occurrence ◽  
Deep Zone ◽  
Carijoa Riisei ◽  
Malpelo Island

During three expeditions to the island (2009 and 2010), the diversity, abundance and status of octocorals were explored. Seven species of octocorals were recorded: Leptogorgia alba, Pacifigorgia cf. lacerata, Pacifigorgia sp.1 y Pacifigorgia sp.2, Muricea cf. fruticosa, Muricea sp., and the invasive species Carijoa riisei. Octocorals form dense aggregations in rocky walls and cliffs, with higher abundances between 10 and 20 m, reaching up to 20 colonies m-2. The most abundant species was Pacifigorgia cf. lacerata with a dominance of more than 60 % and a frequency of occurrence of 100 % for all visited sites. According to depth, three well-defined zones were determined for most sites. A deep zone between 25 and 40 m with an exclusive dominance of L. alba, a shallow assemblage between 7 and 20 m dominated by Pacifigorgia spp., and a transition zone between 18 and 25 m with a mixture of L. alba and P. cf. lacerata. Surprisingly, during November 2009, diseases of possible fungal origin visibly affected populations of Leptogorgia and Pacifigorgia. Subsequently, during February 2010 the same populations of octocorals were monitored and up to 66 % of the colonies were already dead in some locations. Leptogorgia had a significant reduction at El Arrecife site, while Pacifigorgia cf. lacerata had high mortality at La Nevera and El Freezer sites, and a recovery in El Arrecife. There was a notable improvement in disease prevalence by July 2010 with less than 10 % of diseased colonies. The invasive species C. riisei was observed in La Catedral and El Monstruo bank. Thus, this information increases considerably the knowledge of octocorals on Malpelo Island and is the first warning of possible threats against local octocoral populations, such as fungal diseases and the invasive octocoral C. riisei.

Chaetognaths in the South Adriatic: vertical distribution and feeding

2003 ◽  
Vol 83 (6) ◽  
pp. 1301-1306 ◽  
Author(s):  
Mirna Batistić ◽  
Josip Mikuš ◽  
Jakica Njire
Keyword(s):  
Vertical Distribution ◽  
Abundant Species ◽  
Reproductive Period ◽  
The South ◽  
Main Food ◽  
Open Sea ◽  
First Time ◽  
Prey Items

Feeding and vertical distribution of pelagic chaetognaths were studied at coastal and open-sea stations in the northern part of the South Adriatic Pit during five cruises from April 1993 to February 1995. Chaetognaths were more numerous in the upper 100 m, decreased conspicuously with depth, and were captured only rarely between 600 and 1000 m. Copepods were the main food for the most abundant species in all layers. Cannibalism was evident in all species. Feeding on fertilized chaetognath eggs by Pseudosagitta lyra and Mesosagitta decipiens is reported for the first time. The food containing ratio (FCR) and number of prey items per chaetognath (NPC) of Flaccisagitta enflata were highest during the reproductive period. Higher FCRs and NPCs for M. decipiens and P. lyra were noted below 100 m, where the contribution of older specimens increased with depth and the abundance of copepods decreased.

Abundance and diurnal vertical distribution of fish larvae in early spring and summer in a fjord at South Georgia

1992 ◽  
Vol 4 (4) ◽  
pp. 405-412 ◽  
Author(s):  
A. W. North ◽  
A. W. A. Murray
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Fish Larvae ◽  
Abundant Species ◽  
Early Spring ◽  
Distinct Pattern ◽  
South Georgia ◽  
Gobionotothen Gibberifrons ◽  
Lepidonotothen Larseni ◽  
Distribution Of Fish

The diurnal vertical distribution and abundance of fish larvae was studied by net samples in the 265 m deep fjord of Cumberland East Bay, South Georgia. In early spring the six most abundant species of fish larvae in the upper 200 m of the water column were Champsocephalus gunnari, Lepidonotothen nudifrons, Pseudochaenichthys georgianus, Chaenocephalus aceratus, Parachaenichthys' georgianus and Electrona antarctica. In summer, the larvae of C. gunnari, Gobionotothen gibberifrons, Lepidonotothen larseni and Trematomus hansoni were most abundant, and the majority were found in the upper 140 m of the water column, with greatest densities in the top 2m. During both seasons most species showed some evidence of diurnal vertical migration. A distinct pattern was found for C. gunnari in summer; they were at 0–20 m during the day and 60–100 m at midnight. Net avoidance by the larvae of most species was greater before sunset in early spring, and during all periods of daylight in summer, than at other times of day.

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