STUDIES OF MARINE PLANKTONIC DIATOMS: I. CYCLOTELLA NANA HUSTEDT, AND DETONULA CONFERVACEA (CLEVE) GRAN.

1962 ◽  
Vol 8 (2) ◽  
pp. 229-239 ◽  
Author(s):  
Robert R. L. Guillard ◽  
John H. Ryther
Keyword(s):  
Continental Shelf ◽  
Narragansett Bay ◽  
Vitamin B ◽  
Centric Diatom ◽  
Sargasso Sea ◽  
Planktonic Diatoms ◽  
Physiological Differences ◽  
Electron Microscopes ◽  
Morphological Differences

Bacteria-free clones of the small centric diatom Cyclotella nana Hustedt were isolated, three from estuarine localities, one from Continental Shelf waters, and one from the Sargasso Sea. Detonula confervacea was isolated from Narragansett Bay. Morphology of all clones was studied with the light and electron microscopes. Morphological differences between clones of C. nana do not at present warrant separating any as distinct species.Clones of C. nana require only vitamin B12; D. confervacea has no vitamin requirement.Growth of the estuarine clones of C. nana was unaffected by salinity down to 0.5‰ and increased with temperature to 25 °C. The Shelf clone grew more rapidly at salinities above 8‰ and at temperatures between 10° and 20 °C. The Sargasso Sea clone did not survive below 15 °C or 17.5‰, while D. confervacea did not survive at temperatures above 15° or at salinities below 8‰. The physiological differences between clones correspond roughly to the conditions obtaining in nature where each was collected.

scholarly journals Direct observations of American eels migrating across the continental shelf to the Sargasso Sea

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Mélanie Béguer-Pon ◽  
Martin Castonguay ◽  
Shiliang Shan ◽  
José Benchetrit ◽  
Julian J. Dodson
Keyword(s):  
Continental Shelf ◽  
Sargasso Sea ◽  
Direct Observations ◽  
American Eels

Ultrastructure of the zoospore of Blastocladia ramosa (Blastocladiales)

1983 ◽  
Vol 61 (12) ◽  
pp. 3502-3513 ◽  
Author(s):  
Wilma L. Lingle ◽  
William E. Barstow
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Enzymatic Digestion ◽  
Storage Material ◽  
Fermentative Metabolism ◽  
Lipid Globule ◽  
Striated Rootlet ◽  
Physiological Differences ◽  
Morphological Differences

Species of Blastocladia, unlike other members of the order Blastocladiales, have an obligately fermentative metabolism. The ultrastructure of the zoospores of Blastocladia ramosa is described and compared with that of zoospores of aerobic members of the Blastocladiales. Zoospores of Blastocladia ramosa are structurally similar to other blastocladialean zoospores in that they have (i) a nuclear cap composed of aggregated ribosomes delimited by an envelope of endoplasmic reticulum; (ii) a posteriorly located nucleus; (iii) nine sets of microtubules that surround the nucleus and nuclear cap; and (iv) a striated rootlet associated with the kinetosome. Zoospores of Blastocladia ramosa differ by having mitochondria with unusual fine structure and by lacking microbodies and microbody – lipid globule complexes. As shown by enzymatic digestion and staining, glycogen appears to be the primary storage material in the zoospore. Structures which resemble water expulsion vacuoles are present. The morphological differences between zoospores of Blastocladia ramosa and other zoospores of the Blastocladiales appear to be related to physiological differences.

Leptychaster kerguelenensis (Echinodermata: Asteroidea) from Southwest Atlantic: Redescription and geographic distribution

Zootaxa ◽  
2011 ◽  
Vol 2971 (1) ◽  
pp. 59
Author(s):  
MARIELA V. ROMANELLI ◽  
ALEJANDRO TABLADO
Keyword(s):  
Continental Shelf ◽  
Geographic Distribution ◽  
Junior Synonym ◽  
Southwest Atlantic ◽  
Kerguelen Islands ◽  
Morphological Differences

The only two specimens of Leptychaster spp. reported from Southwest Atlantic, were determined as L. kerguelenensis mendosus by Fisher (1940). Twelve specimens of Leptychaster kerguelenensis from Argentine continental shelf collected by the R/V Shinkai Maru, and two specimens from Kerguelen Islands collected by B.A.N.Z.A.R.E., were used to redescribe the species. All the material is deposited at the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". All Atlantic specimens agree with the description of Leptychaster kerguelenensis and no morphological differences were found with specimens from Kerguelen Islands. From the present study, no subspecies are recognized within L. kerguelenensis and L. mendosus is a junior synonym of the former.

Altivasum Hedley, 1914 (Gastropoda: Turbinellidae) from South Western Australia

The Festivus ◽  
2018 ◽  
Vol 50 (4) ◽  
pp. 245-255
Author(s):  
Aart Dekkers ◽  
Stephen Maxwell
Keyword(s):  
Continental Shelf ◽  
Western Australia ◽  
Distinct Species ◽  
Current Understanding ◽  
The South ◽  
Geographic Separation ◽  
Western Side ◽  
Morphological Differences ◽  
Great Australian Bight ◽  
Western Australian

This paper seeks to correct the erroneous taxonomy associated with the current understanding of the Altivasum flindersi (Verco, 1914) complex based on type revision, morphological differences and geographic separation. Structurally, there are three distinct species that can be differentiated, Altivasum flindersi (Verco, 1914), A. typicum Hedley, 1916 and A. profundum sp. nov. Geographically, these species are not all sympatric, with A. typicum restricted to shallower waters, at depths around 20-180 m off the south Western Australian coast, whereas A. profundum is located at the edge of the South Western Australian continental shelf, and A. flindersi is found off the coast of the Great Australian Bight at similar depths to A. typicum. There is an overlap in distribution between A. typicum Hedley, 1916 and A. flindersi (Verco, 1914) on the western side of the Great Australian Bight where they are often associated with similar habitats.

Larval fishes of a Middle Atlantic Bight estuary: assemblage structure and temporal stability

1999 ◽  
Vol 56 (2) ◽  
pp. 222-230 ◽  
Author(s):  
David A Witting ◽  
Kenneth W Able ◽  
Michael P Fahay
Keyword(s):  
Continental Shelf ◽  
Dominant Species ◽  
Fish Assemblages ◽  
Larval Fish ◽  
Temporal Stability ◽  
Temperature Cycle ◽  
Sargasso Sea ◽  
Larval Fishes ◽  
Middle Atlantic ◽  
Lower Temperature

We collected weekly, quantitative ichthyoplankton samples over 6 years (1989-1994, 1309 samples) to identify temporal scales of variability in the abundance and occurrence of larval fish assemblages near Little Egg Inlet in southern New Jersey, U.S.A. We collected species that spawn in the estuary (30%), both the estuary and continental shelf (35%), continental shelf (25%), and the Sargasso Sea (10%). The following analyses suggest an annually repeated seasonal progression of species assemblages: (i) the rank abundance of the 20 dominant species did not change significantly from year to year, (ii) variation in the density of the dominant species was primarily explained by intraannual rather than interannual variation, and (iii) multivariate analysis of the assemblage matrix identified five seasonal assemblages that occurred during all six years. We found that the timing and duration of each of these seasonal groups were correlated with two characteristics of the annual temperature cycle, magnitude (higher or lower temperature) and trajectory (increasing vs decreasing temperature). We suggest that the repeated occurrence of larval fish assemblages in temperate estuaries along the U.S. coast may, in part, be driven by local environmental processes.

Do Leptocephali of the European Eel Swim to Reach Continental Waters? Status of the Question

1998 ◽  
Vol 78 (1) ◽  
pp. 285-306 ◽  
Author(s):  
J.D. McCleave ◽  
P.J. Brickley ◽  
K.M. O'Brien ◽  
D.A. Kistner ◽  
M.W. Wong ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Anguilla Anguilla ◽  
Late Winter ◽  
European Eel ◽  
Sargasso Sea ◽  
North East ◽  
Nutritional Mode ◽  
Mid Atlantic Ridge ◽  
One Year ◽  
European Coast

We examined recent arguments that leptocephali of the European eel,Anguilla anguilla, swim in an oriented manner, rather than drift, to reach the continental shelf of Europe and the Mediterranean Sea. There is a cline of increasing body length of leptocephali from south to north and from west to east from the Mid-Atlantic Ridge (30°W) to the continental shelf, which could represent migration from south-west to north-east, transport eastward at all latitudes, or increased growth rate with latitude. Evidence that this cline is a trend in age of arriving glass eels along the European coast, and that the duration of migration is less than one year, is weak. Ages reported in the literature for specimens from Morocco to The Netherlands were based on the unvalidated assumption that rings in otoliths were deposited daily. The assumption is unwarranted because of low metabolic rate and uncertainty of nutritional mode of leptocephali. If the assumption were accepted, calculated hatching dates of eels arriving at the European coast imply year-round spawning. Lengths of leptocephali in the Sargasso Sea at various times imply that eels spawn only in late winter and spring. Leptocephali contain tiny amounts of muscle, especially aerobic muscle for sustained swimming. They probably have insufficient capability to swim across the Atlantic in the less than 1–2 y reported by others.

Subtropical pupping ground for a cold-water shark

2010 ◽  
Vol 67 (5) ◽  
pp. 769-773 ◽  
Author(s):  
Steven E. Campana ◽  
Warren Joyce ◽  
Mark Fowler
Keyword(s):  
Life History ◽  
Continental Shelf ◽  
Gulf Stream ◽  
Cold Water ◽  
Mature Female ◽  
Life History Stage ◽  
Sargasso Sea ◽  
Eastern Canada ◽  
Northern And Southern Hemispheres ◽  
Conservation And Management

Porbeagle sharks ( Lamna nasus ) are large pelagic sharks apparently restricted to the cold temperate waters of the northern and southern hemispheres. Despite considerable knowledge of their biology, their pupping (birthing) grounds have never been identified. Pop-up archival transmission tags applied to 21 sharks off eastern Canada indicated that males and immature sharks of both sexes remained primarily on the continental shelf for periods of up to 348 days after tagging. However, mature female porbeagles migrated up to 2356 km through the winter, at depths down to 1360 m beneath the Gulf Stream, to a subtropical pupping ground in the Sargasso Sea. In addition to this pupping ground being well south of their documented range, the placement of such a key life history stage in international, largely unregulated waters poses problems for the conservation and management of a species that is largely fished in Canadian waters.

scholarly journals A pelagic marine diatom requiring cobalamin

1955 ◽  
Vol 34 (2) ◽  
pp. 229-231 ◽  
Author(s):  
M. R. Droop
Keyword(s):  
Skeletonema Costatum ◽  
Ph Control ◽  
Marine Diatom ◽  
Vitamin B ◽  
Centric Diatom ◽  
Vital Factor

A bacteria-free culture of the important centric diatom Skeletonema costatum has recently been established at Millport, and some exploratory nutritional experiments have been carried out with it. S. costatum is a photo-autotroph whose autotrophy is, apparently, limited to cobalamin (vitamin B12).Details concerning isolation and maintenance of S. costatum differ from those already published (Droop, 1954a, 1955) only in the matter of pH control, a vital factor in the successful culture of this species whose range of tolerance is narrow (pH 7–5–8–5).

scholarly journals New record of planktonic diatoms from the Sundarban Mangrove Forests, Bangladesh

1970 ◽  
Vol 40 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Abdul Aziz
Keyword(s):  
Key Words ◽  
New Record ◽  
Centric Diatom ◽  
Mangrove Forests ◽  
Planktonic Diatoms ◽  
Sundarban Mangrove ◽  
Unidentified Species

Botanical expedition to the Sundarban Mangrove Forests in the Bangladesh part revealed the presence of 14 diatom taxa not recorded so far from Bangladesh territory. The taxa are Amphiprora alata Kütz., Chaetoceros pendulus Karsten, Chaetoceros socialis Lauder, Cyclotella comta (Ehr.) Kütz. Thalassionema nitzschioides (Grun.) Meresch, Thalassiosira rotula Meunier, Thalassiosira weisflogii Grun., Lioloma delicatula (Cupp) Hasle, Navicula brekkaensis Petersen fa, Nitzschia inconspicua Grun. fa, Nitzschia romana Grun., Surirella fastuosa var. recedens (Schm.) Cl. Besides these, unidentified species of Chaetoceros sp. and an unidentified centric diatom have been recorded. These newly recorded taxa are described and illustrated. Key words: Phytoplankton; Diatoms; Mangrove; Estuarine algae; Centrales; Pennales DOI: http://dx.doi.org/10.3329/bjb.v40i2.9772   Bangladesh J. Bot. 40(2): 163-169, 2011 (December)  

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