scholarly journals Distribution and annual occurrence of Chaetognatha off Cananeia and Santos coast (São Paulo, Brazil)

1968 ◽  
Vol 17 (1) ◽  
pp. 33-55 ◽  
Author(s):  
M. S. de Almeida Prado
Keyword(s):  
Coastal Water ◽  
Annual Variation ◽  
Abundant Species ◽  
Breeding Period ◽  
Shelf Water ◽  
Vertical Movements ◽  
Tropical Water ◽  
The Vertical Distribution ◽  
Water Species ◽  
Different Levels

Plankton samples were fortnightly taken at three fixed stations off Cananéia (1958, 1959, 1960) and off Santos (1960, 1961) by vertical hauling. They contained the following species: Sagitta enflata, S. friderici, S. hispida, S. minima, S. serratodentata, Krohnitta pacifica and Pterosagitta draco. S. frideriei is a typical coastal water species. S. enflata is a typical shelf water species. S. hispida and K. pacifica were present more frequently in shelf water but they were sometimes very abundant in coastal water. S. serratodentata, S. minima and P. draco occurred sparingly in tropical water, however, very few samples were taken in this water mass. Three different maturity stages were established (juvenile, intermediate and adult) in order to study the annual variation of the Chaetognatha. A special breeding period throughout the year was not observed as great swarms of juveniles and intermediates were found in spite of the very small number of adults. Two series of samples taken off Santos at a fixed station (Pt. III) during a period of 24 hours in three different levels were also counted to study the vertical distribution of the Chaetognatha in this area. The three most abundant species were: S. enflata, S. hispida and K. pacifica. S. enflata was more frequent at mid-water. S. hispida and K. pacifica seemed to prefer the surface layer. The thermocline did not affect their vertical migration except for S. hispida. There is indication that S. serratodentata performs vertical movements. S. minima seems to live below 25 m depth. K. subtilis occurred exceptionally in this vertical series of samples.

scholarly journals Studies on chaetognaths off Ubatuba region, Brazil: I. distribution and abundance

1994 ◽  
Vol 42 (1-2) ◽  
pp. 73-84 ◽  
Author(s):  
Tsui Hua Liang ◽  
Luz Amelia Vega-Pérez
Keyword(s):  
Population Structure ◽  
Coastal Water ◽  
Dominant Species ◽  
Sao Paulo ◽  
Shelf Water ◽  
Multidisciplinary Research ◽  
Hydrological Conditions ◽  
Paulo State ◽  
Tropical Water ◽  
São Paulo State

The distribution of chaetognath species off Ubatuba region, São Paulo State, Brazil, was studied during a program of multidisciplinary research. Ten species belonging to the genera Sagitta, Krohnita and Pterosagitta were identified. S. enflata was the dominant species followed by S.friderici and S. hispida. The species S. enflata, S. hispida, S. tenuis, S. bipunctata and JC pacifica were found in the Shelf water whereas S. serratodentata, S. minima, S. hexaptera and P. draco in the Tropical water. Only S. friderici was found associated to Coastal water. Hydrological conditions affected population structure, size of individuals and abundance.

Effect of extremely severe winters on under-ice phytoplankton development in a mesotrophic lake (Eastern Poland)

2014 ◽  
Vol 43 (2) ◽  
Author(s):  
Władysława Wojciechowska ◽  
Tomasz Lenard
Keyword(s):  
Water Column ◽  
Dominant Species ◽  
Biomass Concentration ◽  
Thermal Conditions ◽  
Ice Cover ◽  
Abundant Species ◽  
Blue Green Algae ◽  
Cyanobacteria And Algae ◽  
Taxonomic Groups ◽  
The Vertical Distribution

AbstractThe research was carried out in a mesotrophic and dimictic lake during winters with ice cover. In the last forty years, the development of phytoplankton was analyzed in five extreme winter seasons. The studies of phytoplankton characteristics in the water column took into account values of biomass, concentration of chlorophyll-a and species composition, including dominant species. Differences in the vertical distribution of flagellate and non-flagellate species belonging to cyanobacteria and algae were analyzed in the gradient of light and thermal conditions. The phytoplankton biomass was low and vertically differentiated, with the lowest values at the deeper part of the water column. Flagellate species from the group of Cryptophyceae, Chrysophyceae and Dinophyceae were most abundant. Species biodiversity was low but every winter the dominant species represented different taxonomic groups. In some periods, larger non-motile phytoplankton species from green or blue-green algae dominated. The research proved that the development of phytoplankton under the ice cover was limited mainly by light and, to a lesser extent, by temperature.

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.

Tanaidacea (Crustacea: Peracarida) from Japan. IV. Shallow-water species from Akajima with notes on the recolonization potential of tanaids

Zootaxa ◽  
2008 ◽  
Vol 1678 (1) ◽  
pp. 1 ◽  
Author(s):  
KIM LARSEN ◽  
MICHITAKA SHIMOMURA
Keyword(s):  
Phylogenetic Analysis ◽  
Shallow Water ◽  
New Genus ◽  
Abundant Species ◽  
Two New Species ◽  
Sandy Habitat ◽  
Nansei Islands ◽  
Shallow Water Species ◽  
Water Species ◽  
Preliminary Phylogenetic Analysis

Two new species of tanaids were collected from colonization traps deployed in a shallow water, sandy habitat off Akajima, Nansei Islands. One new parapseudidaen, Parapseudes arenamans, and one new nototanaidaen genus and species, Paranesotanais longicephalus, are described herein. A preliminary phylogenetic analysis of the closest genera confirms the validity of the new genus and suggests a close affinity between the Leptocheliidae and Nototanaidae. Paranesotanais longicephalus was by far the most abundant species in the habitat. Parapseudes arenamans is faster in colonization of vacant substrate (opportunistic species), while being an inferior competitor to Paranesotanais longicephalus later in succession. A key to Nesotanais and Paranesotanais is provided.

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.

scholarly journals Tracing latitudinal gradient, river discharge and water masses along the subtropical South American coast using benthic Foraminifera assemblages

2012 ◽  
Vol 72 (3 suppl) ◽  
pp. 723-759 ◽  
Author(s):  
PPB Eichler ◽  
AR Rodrigues ◽  
BB Eichler ◽  
ES Braga ◽  
EJD Campos
Keyword(s):  
Benthic Foraminifera ◽  
River Discharge ◽  
Latitudinal Gradient ◽  
South American ◽  
Shelf Water ◽  
Silicate Concentration ◽  
Tropical Water ◽  
Freshwater Influence ◽  
Antarctic Shelf ◽  
High Silicate

More than 30% of Buccella peruviana (D'Orbigny), Globocassidulina crassa porrecta (Earland & Heron-Allen), Cibicides mackannai (Galloway & Wissler) and C. refulgens (Montfort) indicate the presence of cold Sub Antarctic Shelf Water in winter, from 33.5 to 38.3º S, deeper than 100 m, in the southern part of the study area. In summer, the abundance of this association decreases to less than 15% around 37.5-38.9º S where two species (Globocassidulina subglobosa (Brady), Uvigerina peregrina (Cushman) take over. G. subglobosa, U. peregrina, and Hanzawaia boueana (D'Orbigny) are found at 27-33º S in both seasons in less than 55 m deep in the northern part, and are linked with warm Subtropical Shelf Water and Tropical Water. Freshwater influence was signalized by high silicate concentration and by the presence of Pseudononion atlanticum (Cushman), Bolivina striatula (Cushman), Buliminella elegantissima (D'Orbigny), Bulimina elongata (D'Orbigny), Elphidium excavatum (Terquem), E. poeyanum (D'Orbigny), Ammobaculites exiguus (Cushman & Brönnimann), Arenoparrella mexicana (Kornfeld), Gaudryina exillis (Cushman & Brönnimann), Textularia earlandi (Parker) and thecamoebians in four sectors of the shelf. The presence of Bulimina marginata (D'Orbigny) between 34.1-32.8º S in the winter and 34.2-32.7º S in the summer indicates that the influence of the Subtropical Shelf Front on the sediment does not change seasonally, otherwise, the presence of Angulogerina angulosa (Williamson) in the winter, only in Mar del Plata (38.9º S), show that Malvinas currents are not influencing the sediment in the summer.

scholarly journals Vertical movements of “escaped” farmed Atlantic salmon (Salmo salar L.)—a simulation study in a western Norwegian fjord

2009 ◽  
Vol 66 (2) ◽  
pp. 278-288 ◽  
Author(s):  
Ove T. Skilbrei ◽  
Jens Christian Holst ◽  
Lars Asplin ◽  
Marianne Holm
Keyword(s):  
Atlantic Salmon ◽  
Vertical Distribution ◽  
Salmo Salar ◽  
Simulation Study ◽  
Vertical Movements ◽  
Atlantic Salmon Salmo Salar ◽  
Wide Range ◽  
Norwegian Fjord ◽  
Farmed Atlantic Salmon ◽  
The Vertical Distribution

Abstract Skilbrei, O. T., Holst, J. C., Asplin, L., and Holm, M. 2009. Vertical movements of “escaped” farmed Atlantic salmon (Salmo salar L.)—a simulation study in a western Norwegian fjord. – ICES Journal of Marine Science, 66: 278–288. To study the vertical distribution of fish that had been allowed to escape, farmed Atlantic salmon were tagged with acoustic tags equipped with depth sensors, and then released on five different dates in the course of a year from two fish farms in the Hardanger Fjord in western Norway. Release stimulated the fish to dive to deeper than 15 m during the first hours or days post-release, often down to 50–80 m. However, during the following 4 weeks, most of the escapees spent most of their time above the pycnocline at depths of 0–4 m. The fish were more widely distributed in the water column after release during winter, but still spent most of the time in the cold surface layers. There was a wide range in the vertical distribution of individual fish, and the proportion of detections below 14-m depth ranged from 0 to 90%. There was a significant diurnal cycle in all seasons except midsummer, when the fish were less abundant in the upper layer during daylight, especially on brighter days. The results suggest that salmon diving activity following escape may complicate the recapture of escaped fish at the farm site but that the subsequent tendency of most fish to stay near the surface, virtually irrespective of the time of year, may facilitate recapture.

scholarly journals Diel dynamic of phytoplankton functional groups in a tropical water supply, Extremoz Lake, northeastern Brazil

2014 ◽  
Vol 26 (4) ◽  
pp. 356-366 ◽  
Author(s):  
Thársia da Silva Pinto ◽  
Vanessa Becker
Keyword(s):  
Vertical Distribution ◽  
Functional Groups ◽  
Northeastern Brazil ◽  
Severe Drought ◽  
Dry Period ◽  
Drought Period ◽  
Tropical Water ◽  
Phytoplankton Functional Groups ◽  
The Vertical Distribution ◽  
Dry And Rainy Seasons

AIM: This study analyzed - the diel and vertical dynamics of phytoplankton functional groups in a natural tropical lake (Extremoz Lake, northeast Brazil), to investigate and understand the driver factors of the community during a severe drought period. METHODS: Sampling of the abiotic variables and phytoplankton was performed at intervals of 6 hours over 24 hours in vertical profiles, in dry and rainy seasons (according to the historical average). The phytoplankton species were grouped according to the functional groups' approach sensu Reynolds et al. (2002). RESULTS: October/12 was considered as a dry period (18.4 mm), while March/13, due to the historical average, as a rainy season, due to the low rainfall during the study period (15.7 mm), it was called severe drought. The lake showed thermal and chemical destratification in both periods. Phytoplankton biomass was higher in the dry season and their vertical distribution was stratified in both periods. In both samplings there were less algal biomass during the night. Phytoplankton functional groups of mixed and shallow systems (S1, L0 and K) were descriptors throughout the study period with higher biomass always registered in the group S1, represented by Planktolyngbya limnetica (Cyanobacteria). CONCLUSION: The lack of seasonality observed in this study, due to prolonged drought, may have influenced the pattern of homogeneous behavior in both samplings. This pattern strongly influenced the vertical distribution of phytoplankton in the two periods, with a constancy of dominance of functional descriptors groups.

Phytoplankton species successions and their hydrological environment at a coastal station off Sydney

1986 ◽  
Vol 37 (3) ◽  
pp. 361 ◽  
Author(s):  
GM Hallegraeff ◽  
DD Reid
Keyword(s):  
Coastal Waters ◽  
Early Summer ◽  
Phytoplankton Species ◽  
Species Occurrence ◽  
Short Term ◽  
Coastal Station ◽  
Tropical Water ◽  
Diatom Blooms ◽  
Autumn And Winter ◽  
Water Species

Phytoplankton species occurrence was studied during 1978-1981 at a coastal station off Sydney and succession patterns were sought using polythetic agglomerative classification analysis. Three major phytoplankton categories were distinguished: (1) a large group of species (including most nanoplankton), which were present throughout the year; (2) a group of diatom species, which bloomed following episodic nutrient enrichments in spring, early summer, autumn and winter; (3) a group of warm-water species (e.g. Trichodesmium), which were associated with admixture of tropical water masses. Gross features of the phytoplankton cycle in these waters are related to the erratic flow pattern of the East Australian Current. However, clear short-term (4-14 weeks) species successions were evident within the spring and summer diatom blooms. These began with small diatoms (Asterionella, Leptocylindrus, Skeletonema, Thalassiosira) followed first by large diatoms (Detonula, Rhizosolenia, Stephanopyxis) and then by large dinoflagellates (Ceratium, Protoperidinium). This sequence is identical to that observed in coastal waters of other parts of the world. A phytoplankton checklist (280 species) for Sydney coastal waters is included as an appendix.

scholarly journals Response of sub-ice platelet layer thickening rate to variations in Ice Shelf Water supercooling in McMurdo Sound, Antarctica

2018 ◽  
Author(s):  
Chen Cheng ◽  
Adrian Jenkins ◽  
Paul R. Holland ◽  
Zhaomin Wang ◽  
Chengyan Liu ◽  
...  
Keyword(s):  
Nonlinear Effects ◽  
Crystallographic Structure ◽  
Shelf Water ◽  
Ice Shelf ◽  
Mcmurdo Sound ◽  
Frazil Ice ◽  
Ice Concentration ◽  
Vertical Distributions ◽  
Ice Shelf Water ◽  
The Vertical Distribution

Abstract. Persistent outflow of supercooled Ice Shelf Water (ISW) from beneath McMurdo Ice Shelf creates a sub-ice platelet layer (SIPL) having a unique crystallographic structure under the sea ice in McMurdo Sound (MMS), Antarctica. A new frazil-ice-laden ISW plume model that encapsulates the combined nonlinear effects of the vertical distributions of supercooling and frazil ice concentration (FIC) on frazil ice growth is applied to MMS, and is shown to reproduce the observed ISW supercooling and SIPL distributions. Using this model, the dependence of SIPL thickening rate on ISW supercooling in MMS is investigated. Results are found to be sensitive to the choice of frazil ice suspension index, which determines the vertical distribution of FIC. For each suspension index, SIPL thickening rate can be expressed as an exponential function of ISW supercooling. The complex dependence on FIC highlights the need to improve frazil ice observations within the ice-ocean boundary layer.

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