Recherches sur les Alaria (Phaeophyceae) de l'est canadien. I. Nombres chromosomiques et identité des Alaria de l'estuaire du St-Laurent

1974 ◽  
Vol 52 (4) ◽  
pp. 691-694 ◽  
Author(s):  
M.-J. Feller-Demalsy ◽  
P. Demalsy
Keyword(s):  
Chromosome Number ◽  
Single Species ◽  
Chromosome Counts ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
Haploid Chromosome Number ◽  
Biosystematic Study ◽  
Alaria Esculenta ◽  
St Lawrence Estuary

Chromosome counts in gametophytes and sporophylls of Alaria collected in the St. Lawrence Estuary show that all the specimens of this genus in eastern Canada may not belong to the single species A. esculenta Greville. Indeed, the haploid chromosome number (n) found in these algae is equal to half of the number attributed in the literature to Alaria esculenta from the British coasts. Three hypotheses for the interpretation of these observations are considered. The solution of the problem of the identity of Alaria can only be hoped for from their global, morphological, and biosystematic study.

Marine tube-dwelling diatoms of eastern Canada: descriptions, checklist, and illustrated key

1984 ◽  
Vol 62 (4) ◽  
pp. 778-794 ◽  
Author(s):  
Christopher S. Lobban
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Common Species ◽  
Bay Of Fundy ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
The Common ◽  
Living Material ◽  
St Lawrence Estuary ◽  
A New Species

From a study of living materials and specimens in several regional herbaria, a list has been drawn up of all the common and several of the rarer tube-dwelling diatoms of eastern Canada. Descriptions, illustrations of living material and acid-cleaned valves, and a key to the species are provided. Most specimens were from the Atlantic Provinces and the St. Lawrence estuary, but a few were from the Northwest Territories. By far the most common species is Berkeleya rutilans. Other species occurring commonly in the Quoddy Region of the Bay of Fundy, and sporadically in space and time elsewhere, arc Navicula delognei (two forms), Nav. pseudocomoides, Nav. smithii, Haslea crucigera, and a new species, Nav.rusticensis. Navicula ramosissima and Nav. mollis in eastern Canada are usually found as scattered cohabitants in tubes of other species. Nitzschia tubicola and Nz. fontifuga also occur sporadically as cohabitants.

Role of the bedrock topography in the Quaternary filling of a giant estuarine basin: the Lower St. Lawrence Estuary, Eastern Canada

2010 ◽  
Author(s):  
Mathieu J. Duchesne ◽  
Nicolas Pinet ◽  
Karine Bédard ◽  
Guillaume St-Onge ◽  
Patrick Lajeunesse ◽  
...  
Keyword(s):  
Eastern Canada ◽  
Lawrence Estuary ◽  
Bedrock Topography ◽  
St Lawrence Estuary

scholarly journals Unprecedented reorganization of holocentric chromosomes provides insights into the enigma of lepidopteran chromosome evolution

2019 ◽  
Vol 5 (6) ◽  
pp. eaau3648 ◽  
Author(s):  
Jason Hill ◽  
Pasi Rastas ◽  
Emily A. Hornett ◽  
Ramprasad Neethiraj ◽  
Nathan Clark ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Chromosome Evolution ◽  
Chromosome Structure ◽  
Holocentric Chromosomes ◽  
Chromosome Counts ◽  
Pieris Napi ◽  
Haploid Chromosome Number ◽  
Genome Wide ◽  
The Face ◽  
Chromosome Level

Chromosome evolution presents an enigma in the mega-diverse Lepidoptera. Most species exhibit constrained chromosome evolution with nearly identical haploid chromosome counts and chromosome-level gene collinearity among species more than 140 million years divergent. However, a few species possess radically inflated chromosomal counts due to extensive fission and fusion events. To address this enigma of constraint in the face of an exceptional ability to change, we investigated an unprecedented reorganization of the standard lepidopteran chromosome structure in the green-veined white butterfly (Pieris napi). We find that gene content in P. napi has been extensively rearranged in large collinear blocks, which until now have been masked by a haploid chromosome number close to the lepidopteran average. We observe that ancient chromosome ends have been maintained and collinear blocks are enriched for functionally related genes suggesting both a mechanism and a possible role for selection in determining the boundaries of these genome-wide rearrangements.

scholarly journals Do Barrow's Goldeneyes, Bucephala islandica, Breed South of the St. Lawrence Estuary in the Gaspé Peninsula, Eastern Canada?

2010 ◽  
Vol 124 (2) ◽  
pp. 179
Author(s):  
Jean-François Ouellet ◽  
Pierre Fradette ◽  
Isabel Blouin
Keyword(s):  
North America ◽  
Breeding Season ◽  
Breeding Habitat ◽  
Eastern North America ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
North Shore ◽  
The North ◽  
Bucephala Islandica ◽  
St Lawrence Estuary

We report the first observations of Barrow's Goldeneyes south of the St. Lawrence estuary in typical breeding habitat during the breeding season. Until recently, the confirmed breeding locations for the species in Eastern North America were all located on the north shore of the Estuary and Gulf of St. Lawrence.

Identification and dating of a key Late Pleistocene stratigraphic unit in the St. Lawrence Estuary and Gulf (Eastern Canada)

2008 ◽  
Vol 27 (25-26) ◽  
pp. 2390-2400 ◽  
Author(s):  
Guillaume St-Onge ◽  
Patrick Lajeunesse ◽  
Mathieu J. Duchesne ◽  
Hubert Gagné
Keyword(s):  
Late Pleistocene ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
Stratigraphic Unit ◽  
St Lawrence Estuary

Diet and feeding behaviour of the sea cucumber Cucumaria frondosa in the St. Lawrence estuary, eastern Canada

1998 ◽  
Vol 76 (6) ◽  
pp. 1194-1198 ◽  
Author(s):  
Jean-Francois Hamel ◽  
Annie Mercier
Keyword(s):  
Feeding Behaviour ◽  
Field Experiments ◽  
Skeletonema Costatum ◽  
Physical Parameters ◽  
Tidal Variation ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
Laboratory Conditions ◽  
St Lawrence Estuary ◽  
Cucumaria Frondosa

Combined laboratory and field experiments showed that sea cucumbers (Cucumaria frondosa) from the St. Lawrence estuary in eastern Canada have well-defined feeding cycles with marked seasonal and tidal variations. Typical feeding behaviour involved extension of the tentacles, which were then successively introduced into the oral cavity. Field observations and analysis of intestinal contents and indices demonstrated that C. frondosa fed mainly during spring and summer. Their diet comprised an abundance of phytoplanktonic cells (Coscinodiscus centralis, Chaetoceros debilis, Skeletonema costatum, and Thalassiosira gravida), with occasional ingestion of small crustaceans and a variety of eggs and larvae. Food types found in the digestive tract were closely related to the periodic abundance of plankton species in the water. Fewer individuals were observed feeding during fall and winter; they mostly ingested nonliving particles and the intestinal indices were low. In field populations, feeding rates were highest during ebb and rising tides, whereas under laboratory conditions without tidal variation, individuals showed no distinct feeding periods. However, individuals maintained under laboratory conditions and periodically provided with phytoplanktonic cells demonstrated a strong ability to detect the food in the water and react accordingly by extending their tentacles and beginning to feed. The results of the study suggest that food availability, rather than physical parameters such as temperature or current, best explains the cyclic feeding behaviour of C.\x11frondosa at seasonal and tidal scales.

Recent transfer of coastal sediments to the Laurentian Channel, Lower St. Lawrence Estuary (Eastern Canada), through submarine canyon and fan systems

2009 ◽  
Vol 29 (3) ◽  
pp. 191-200 ◽  
Author(s):  
Hubert Gagné ◽  
Patrick Lajeunesse ◽  
Guillaume St-Onge ◽  
Andrée Bolduc
Keyword(s):  
Submarine Canyon ◽  
Coastal Sediments ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
St Lawrence Estuary
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