scholarly journals Microphytoplankton structure from the neritic and oceanic regions of Pernambuco State - Brazil

2009 ◽  
Vol 69 (4) ◽  
pp. 1037-1046 ◽  
Author(s):  
ML. Koening ◽  
BE. Wanderley ◽  
SJ. Macedo
Keyword(s):  
Principal Component ◽  
Mesh Size ◽  
Species Number ◽  
Phytoplankton Diversity ◽  
Trichodesmium Erythraeum ◽  
Species Association ◽  
Tropical Water ◽  
Key Species ◽  
Distribution And Ecology ◽  
Planktonic Species

This research was carried out to assess phytoplankton diversity, distribution and ecology on the Pernambuco Continental Shelf and Oceanic region (lat. 7º 33' 00" S to 8º 41' 50" S and long. 34º 04' 47" W to 35º 01' 20" W). Samples were collected during the Joint Oceanographics Projects (JOPS II-Leg 5) by double oblique hauls with a baby bongo net 64 µm mesh size at depth between 14 and 150 m in inshore and offshore waters respectively, in seven transects, totaling 34 stations. The temperature and salinity characterised the tropical water masses. The dissolved oxygen was oversaturated in all stations. The nutrient-low concentrations showed an oligothrophic pattern in the whole area. 173 specific and infraspecific taxa were identified: Dinophyta (103 taxa), Bacillariophyta (61 taxa), Cyanobacteria (7 taxa), Chlorophyta and Chrysophyta (1 taxon). The family Ceratiaceae presented the highest species number (47 taxa). The cyanobacteria Trichodesmium erythraeum Ehrenberg, Oscillatoria spp. and the diatom Leptocylindrus danicus Cleve had higher frequence of occurrence and abundance. Species diversity varied from 0.71 to 3.46 bits.cell-1 and this low index was due to Trichodesmium erythraeum bloom and evenness from 0.14 to 0.65, showing an unstable pattern. The oceanic planktonic species were responsible for the higher richness with 78 taxa, corresponding to 58.39% of the total microphytoplankton. The species association presented two groups. The first one divided in two subgroups: one associated to the neritic/oceanic and oceanic planktonic species and the other to the oligotrophic indicator species. The second group was composed of some key species which were the most abundant and frequent in the area. The first three Principal Component Analyses (PCAs) explained 50.91% of the data variance showing that the area is structured by two groups: one offshore composed by oligotrophic indicators, and another nearshore influenced by continental fluxes.

scholarly journals Composition of Trichiuridae and Gempylidae larvae (Teleostei) and their association with water masses in the Southwest Atlantic Ocean

2009 ◽  
Vol 38 (4) ◽  
Author(s):  
Paulo Júnior ◽  
Christiane de Souza ◽  
Graciela Weiss
Keyword(s):  
Temperature Gradient ◽  
Atlantic Ocean ◽  
Continental Shelf ◽  
Mesh Size ◽  
Water Masses ◽  
Southwest Atlantic ◽  
Patos Lagoon ◽  
La Plata ◽  
Tropical Water ◽  
The Relationship

Composition of Trichiuridae and Gempylidae larvae (Teleostei) and their association with water masses in the Southwest Atlantic OceanIn this paper the relationship between temporal changes in the occurrence of water masses and Trichiuridae and Gempylidae larvae composition and distribution in the Southwest Atlantic ocean were analysed between 25° and 40° S. Ichthyoplankton was collected during the three expeditions of the Subtropical Convergence Project: Winter and Spring 1977, Autumn 1978 and Summer 1981, realized in the Southwest Atlantic waters. Oblique tows were conducted using a Hensen net with 250 μm mesh size. Steep salinity and temperature gradient were found, where the river outflows from La Plata river (Argentina) and Patos Lagoon (Brazil) met the Tropical Water over the continental shelf between 32 and 36° S. We examined 524 Hensen-net samples that contained about 283 larvae from five species of Trichiuridae and Gempylidae. The most abundant and frequent specie were

Analysis of Zooplankton Population Fluctuations in the Strait of Georgia, British Columbia

1977 ◽  
Vol 34 (8) ◽  
pp. 1196-1206 ◽  
Author(s):  
Grant A. Gardner
Keyword(s):  
Canonical Correlation ◽  
Temporal Trends ◽  
Biological Significance ◽  
Principal Component ◽  
Biological Data ◽  
Species Selection ◽  
Hydrographic Data ◽  
Strait Of Georgia ◽  
Key Species ◽  
Principal Component Analyses

Canonical correlation, cluster, multiple regression, factor, and principal component analyses were used to examine zooplankton and hydrographic data over the period of unusual fluctuations in the overwintering population sizes of Calanus plumchrus, C. marshallae, and C. pacificus in the Strait of Georgia. Additional hydrographic data were examined for relationships between physical and biological data 3 and 6 mo out of phase. Analysis indicates a recent subtle temperature and salinity shift of uncertain biological significance. Canonical correlation and principal component analyses suggest that 15% of the variance in the zooplankton is related to a temporal trend paralleling that seen in the physical characteristics of the environment.Based on the factor analysis, C. plumchrus, Pseudocalanus minutas, Acartia longiremus, Sagitta elegans, Euphausia pacifica, Limacina spp, and Oithona spinirostris are suggested as "key" species for future zooplankton monitoring programs. Statistically supported species selection can reduce the time and expense of sorting zooplankton samples without an equivalent reduction of information yield. Key words: zooplankton, populations, Calanus, statistical analysis, temporal trends

scholarly journals COMPOSIÇÃO E DISTRIBUIÇÃO DO FITOPLÂNCTON EM ÁREAS COSTEIRAS E OCEÂNICAS DA REOIAO SUESTE DO BRASIL

1986 ◽  
Vol 1 (3) ◽  
Author(s):  
Frederico Pereira Brandini ◽  
Cristine Louise Braum Moraes
Keyword(s):  
Great Influence ◽  
Nutrient Concentrations ◽  
Brazilian Coast ◽  
Trichodesmium Erythraeum ◽  
Tropical Water ◽  
Brazil Current ◽  
Total Phytoplankton ◽  
Phosphate Nitrate ◽  
Anabaena Sp ◽  
Oligotrophic Condition

Total phytoplankton samples and hydrographical parameters were collected from the surface of 16 stations located in the southeastern sector of the brazilian coast during the autumn cruise of the R/V “ Almirante Saldanha” . The limits of temperature (22 — 25°C) and salinity (35,0 — 37,1 x 10‘s) observed indicated the great influence of the Tropical Water over the sampling area where the oligotrophic condition is certainly due to the low nutrient concentrations of this watermass. Phosphate, nitrate and silicate ranged from 0.0 to 0.63, 1.41 to 5.69 and from 4.10 to 25,25 ftg-at.r1, respectively.The most frequent diatoms were Coscinodiscus spp, Coscinosira sp, Pleurosigma sp, Pseudoeunotia doliolus, Thalassionema nitzschioides, Thalassiothrix frauenfeldii and T. mediterrânea, among 49 species observed. Prorocentrum and Protoperidinium spp dominated the dinoflagellate population although the genus Ceratium was represented by a greater number of species. Cyanophycean cells were abundant in coastal (Anabaena sp) and oceanic (Trichodesmium erythraeum) samples.The phytoplankton community was numerically dominated by nanoplanktonic organisms like phytoflagellates (including monads) and the coccolithophorid Coccolithus huxleyi. The phytoplankton association observed in the present study is typical of oligotrophic warm waters of the Brazil Current. Amostras de fitoplâncton total e parâmetros hidrográficos foram obtidos na superfície de 16 estações localizadas no setor sudeste da costa brasileira durante o outono de 1983. Os limites de temperatura (22 — 25°C) e salinidade (35,0 — 37,1 x10 “) observados indicaram a influência da Água Tropical na área estudada onde as condições oligotróficas são devidas à baixa concentração de nutrientes nessa massa d’água. Fosfato, nitrato e silicato variaram entre 0,0 e 0,63, 1,41 e 5,69, e 4,10 e 25,25 /ig-at.r1, respectivamente.As diatomáceas mais freqüentes foram Coscinodiscus spp, Coscinosira sp, Fleurosigma sp, Pseudoeunotia doliolus, Thalassionema nitszchioides, Thalassiothrix frauenfeldii e T. mediterrânea, dentre as 49 espécies observadas. Prorocentrum e Protoperidinrum spp dominaram a população de dinoflagelados apesar do gênero Ceratium ter apresentado o maior número deespécies. As cianofíceas Anabaena sp e Oscillatoria (=Trichodesmium) erythraeum foram abundantes nas amostras costeiras e oceânicas.A comuindade fitoplanctônica foi numericamente dominada por organismos do nanoplâncton, tais como fitoflagelados (incluindo-se mônadas) e o cocolitoforídeo Coccolithus huxleyi. A associação fitoplanctônica observada no presente trabalho é típica das águas quentes e oligotróficas da Corrente do Brasil.

scholarly journals DIAGNOSTIC AND DESCRIPTION OF ASIAN PANGASIID CATFISH GENUS Helicophagus FROM SOUTHEAST ASIA

2019 ◽  
Vol 25 (2) ◽  
pp. 123
Author(s):  
Rudhy Gustiano ◽  
Muhammad Hunaina Fariduddin Ath-thar ◽  
Vitas Atmadi Prakoso ◽  
Deni Radona ◽  
Irin Iriana Kusmini
Keyword(s):  
Principal Component Analysis ◽  
Southeast Asia ◽  
Principal Component ◽  
Component Analysis ◽  
Type Specimens ◽  
Body Conformation ◽  
Eye Diameter ◽  
Distribution And Ecology

Pangasiid catfishes is an economic important catfish family for fishery. Nowadays, three species, Pangasius hypophtahlmus, P. boucorti, and P. djambal, are used in aquaculture. Among the genera in Pangasiidae, Helicophagus was less studied. Although this genus was less preferred than other popular species in Pangasiidae, it still has high commercial price. The present study was conducted to clarify the differences of the exist species in the genus Helicophagus based on biometric analyses. Twenty six specimens, collected from represent rivers in Southeast Asia, used for the material examined. Several type specimens deposited in museums were also added in the analyses. Thirty five characters were designed for measurement on the unique body conformation. Principal component analysis (PCA) was applied to distinguish different species and found strong characters for key identification and description. The results presented the data and information on the diagnosis, description, distribution, and ecology of each species. Key identification of each species are given. The three species (Helicophagus typus, H. waandersii, and H. leptorhynchus) enabled to show their differences based on eye diameter and vomerine toothplate length.

Crustacean zooplankton communities, mixotrophic cililates, and optical properties in North Patagonian lakes, investigated by remote sensing

Crustaceana ◽  
2020 ◽  
Vol 93 (9-10) ◽  
pp. 1065-1078
Author(s):  
Patricio De los Ríos-Escalante ◽  
Stefan Woelfl ◽  
Patricio Acevedo ◽  
Manuel Castro
Keyword(s):  
Remote Sensing ◽  
Principal Component ◽  
Null Models ◽  
Crustacean Zooplankton ◽  
Species Number ◽  
Patagonian Lakes ◽  
Opposite Situation ◽  
Remote Sensing Techniques ◽  
Zooplankton Communities ◽  
Mixotrophic Ciliates

Abstract North Patagonian lakes are characterized by their oligotrophic or oligo-mesotrophic status. These conditions bring with them, respectively, the presence of abundant mixotrophic ciliates and a low species number of crustacean zooplankton under oligotrophic status, and low numbers of mixotrophic ciliates and a high species number of zooplankton under oligo-mesotrophic status. The aims of the present study are, (1) to use remote sensing techniques for determining abundances of mixotrophic ciliates and crustacean zooplankton, and (2) to characterize these mixotrophic and zooplankton communities by using null models. The sensing was accomplished from a satellite, i.e., by measuring the reflectance of the sunlight on a waterbody, which result will vary according to the contents of the water column. The results of Principal Component Analysis (PCA) revealed that sites with low reflectance of all bands have a high abundance of Stentor accompanied by low zooplankton absolute abundance, whereas a markedly opposite situation was observed under high reflectance, where Stentor has low abundance in conjunction with high zooplankton absolute abundances. The null models revealed that the communities in the studied sites do not have structured species associations, and that there is an overlap of niches. These results obtained agree with similar observations for Argentinean Patagonian lakes.

scholarly journals Multivariate approach to determine the ecological preferences of phytoplankton in Uppanar estuary, southeast coast of India

2021 ◽  
Vol 7 (10) ◽  
pp. 23-33
Author(s):  
P. Damotharan and R. Punniyamoorthy M. Saravanakumar, P. Murugesan,
Keyword(s):  
River Mouth ◽  
Environmental Parameters ◽  
Species Number ◽  
Phytoplankton Species ◽  
Phytoplankton Diversity ◽  
Blue Green Algae ◽  
Phytoplankton Distribution ◽  
Physico Chemical ◽  
Environmental Matching ◽  
Water Ph

In the present study, the phytoplankton diversity and distribution was studied in relation seasonal variation of environmental parameters in the Uppanar estuary. Samples were seasonally collected (i.e., pre-monsoon: July-2018 and summer: June-2019) from six stations. A total of 62 phytoplankton species belonging to three classes, 20 orders, 26 families and 36 genera were and among the three phytoplankton taxa, diatoms topped the list with 41 species followed by Dinoflagellates (17 species) and blue green algae (4 species). The maximum number of phytoplankton species (36) and diversity value (H’) 3.976 was recorded in the stations near river mouth (UE-6) during summer and minimum species number (21) and maximum species richness (d) 6.923 was recorded in stations close to industrialr zone (UE-1) during monsoon. The maximum species evenness (J') 0.928 was recorded at stations near river mouth (UE-6). BIO-ENV (Biota-Environmental matching) and CCA results confirmed that the environmental parameters such as Dissolved oxygen, Turbidity, Salinity, Water pH, Chlorophyll, Silicate, TN and TP as best match (ρω = 0.968) in determining phytoplankton distributions. The results of present study helps to develop an understanding on the phytoplankton distribution based on physico-chemical parameters, which will form a reliable tool in bio-monitoring studies.

scholarly journals Variation of phytoplankton community structure in Quang Ngai coastal waters during 2015–2019

2021 ◽  
Vol 20 (4A) ◽  
pp. 21-33
Author(s):  
Huynh Thi Ngoc Duyen ◽  
Tran Thi Minh Hue ◽  
Tran Thi Le Van ◽  
Phan Tan Luom ◽  
Nguyen Ngoc Lam ◽  
...  
Keyword(s):  
Community Structure ◽  
Environmental Impacts ◽  
Coastal Waters ◽  
Phytoplankton Community ◽  
Environmental Changes ◽  
Diversity Indices ◽  
Species Number ◽  
Phytoplankton Community Structure ◽  
Phytoplankton Diversity ◽  
Phytoplankton Communities

Phytoplankton in coastal waters are important for the evaluation of either biodiversity or environmental impacts because of this highly vulnerable ecosystem. Seasonal and annual changes in the phytoplankton community structure in Quang Ngai waters during the period 2015 to 2019 were analyzed to assess the phytoplankton diversity and reveal possible causes of these changes. A total of 366 phytoplankton taxa belonging to 10 classes were identified throughout this present study. The highest species number was found in 2019 with 295 taxa, followed by those in 2015 (247), 2017 (185), and 2018 (99). The waters of Ly Son transect showed the highest diversity and most stable phytoplankton communities in both dry and rainy seasons, whereas the stations of Quang Ngai coast revealed high variability of the communities. All diversity indices including Margalef, Pielou, Shannon, Simpson did not reflect well differences in average values but a certain degree of variances, indicating possible environmental impacts. During the study time, there were blooms of certain diatom species including Skeletonema spp. in 2015 and Pseudo-nitzschia spp. in 2019. Analysis of a diatoms index, Centric/Pennate ratio, indicated that the waters were in eutrophic status with a decreasing trend from the coast area to Ly Son island in 2015 and 2019. This research built up fundamental data on phytoplankton communities for Quang Ngai province. The Centric/Pennate diatom index and diversity would be used as indicators for environmental changes and their values provided warning of eutrophication in this coastal waters including the water surrounding Ly Son island.

PRELIMINARY RESULTS ON SPECIES COMPOSITION OF AQUATIC INSECTS IN DAI DINH TOWN, TAM DAO DISTRICT, VINH PHUC PROVINCE

2020 ◽  
Vol 65 (10) ◽  
pp. 173-179
Author(s):  
Hieu Nguyen Van
Keyword(s):  
Quantitative Analysis ◽  
Species Composition ◽  
Preliminary Data ◽  
Aquatic Insects ◽  
Rainy Season ◽  
Field Survey ◽  
Aquatic Insect ◽  
Mesh Size ◽  
Functional Feeding Groups ◽  
Species Number

In this study, specimens were collected at 5 different sites. The aquatic insects were collected both quantitatively by Surber net (size 50 cm × 50 cm, mesh size 0.2 mm) and qualitatively by hand net and pond net. A field survey was conducted in December 2019 (dry season) and in June 2020 (rainy season). The study aims to show the preliminary data on faunas and communities of aquatic insects in Dai Dinh town, Tam Dao district, Vinh Phuc province. As a result, a total of 91 aquatic insect species belonging to 76 genera, 44 families, and 9 orders were recognized. Among these, the order Ephemeroptera had the highest species number with 32 species; followed by order Trichoptera with 18 species; order Odonata with 16 species; order Coleoptera with 8 species; order Hemiptera and Diptera with 6 species, each; order Plecoptera with 3 species. Order Lepidoptera and Megaloptera had the lowest of species number, represented by 1 species for each order. Besides, the quantitative analysis results and the functional feeding groups were provided in this study.

scholarly journals The Extent of Infrastructure Causing Fragmentation in the Hydrocarbon Basin in the Arid and Semi-Arid Zones of Patagonia (Argentina)

2019 ◽  
Vol 11 (21) ◽  
pp. 5956
Author(s):  
Buzzi ◽  
Rueter ◽  
Ghermandi ◽  
Lasaponara
Keyword(s):  
Principal Component ◽  
Mesh Size ◽  
Oil Production ◽  
Landscape Fragmentation ◽  
Arid Zones ◽  
Effective Mesh Size ◽  
The Mean ◽  
Patch Density ◽  
Landscape Units ◽  
Semi Arid

Fragmentation is a disruption in the connectivity of landscapes. The aims of this paper are (i) to quantitatively assess the fragmentation rates in three landscape units located in a hydrocarbon basin, and (ii) to model their behavior between 2001 and 2013 using landscape metrics at different scales of resolution. The following metrics were selected using principal component analysis (PCA): The Clumpiness Index (CLUMPY), patch density (PD), perimeter-area fractal dimension (PAFRAC) and effective mesh size (MESH). Results from our investigations pointed out that hydrocarbon activity increased the fragmentation at the sites. In particular, the CLUMPY index increased in all three landscape units, the average of PD decreased from 60 to 14 patches per 100 hectares, whereas the mean of MESH was quite constant, however, due to oil production, it decreased mainly in the coastal valleys. Finally, the PAFRAC also decreased at sites with oil production, being more evident in the plateau and coastal canyons. As a whole, outputs from our analyses clearly pointed out that the monitoring of landscape fragmentation trends in arid and semi-arid zones can be successfully achieved using metrics derived from satellite spectral information.

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