scholarly journals Reconstruction of east–west deep water exchange in the low latitude Atlantic Ocean over the past 25,000 years

2017 ◽  
Vol 458 ◽  
pp. 327-336 ◽  
Author(s):  
Jacob N.W. Howe ◽  
Alexander M. Piotrowski ◽  
Rong Hu ◽  
Aloys Bory
1993 ◽  
Vol 71 (5) ◽  
pp. 997-1002 ◽  
Author(s):  
Dale R. Calder

Bougainvillia aberrans n.sp. is described from Bermuda in the western North Atlantic Ocean. Specimens were collected at a depth of 150 fathoms (274 m) from the polypropylene buoy line of a crab trap. The hydroid colony of B. aberrans is erect, with a polysiphonic hydrocaulus, a smooth to somewhat wrinkled perisarc, hydranths having a maximum of about 16 tentacles, and medusa buds arising only from hydranth pedicels. Medusae liberated in the laboratory from these hydroids differ from all other known species of the genus in having a long, spindle-shaped manubrium, lacking oral tentacles, having marginal tentacles reduced to mere stubs, and being very short-lived (surviving for a few hours at most). Gonads develop in medusa buds while they are still attached to the hydroids, and gametes are shed either prior to liberation of the medusae or shortly thereafter. The eggs are surrounded by an envelope bearing nematocysts (heterotrichous microbasic euryteles). The cnidome of both hydroid and medusa stages consists of desmonemes and heterotrichous microbasic euryteles. The diagnosis of the genus Bougainvillia is modified to accommodate this new deep-water species.


2010 ◽  
Vol 68 (2) ◽  
pp. 319-332 ◽  
Author(s):  
F. J. Murillo ◽  
P. Durán Muñoz ◽  
A. Altuna ◽  
A. Serrano

Abstract Murillo, F. J., Durán Muñoz, P., Altuna, A., and Serrano, A. 2011. Distribution of deep-water corals of the Flemish Cap, Flemish Pass, and the Grand Banks of Newfoundland (Northwest Atlantic Ocean): interaction with fishing activities. – ICES Journal of Marine Science, 68: 319–332. The distribution of deep-water corals of the Flemish Cap, Flemish Pass, and the Grand Banks of Newfoundland is described based on bycatch from Spanish/EU bottom trawl groundfish surveys between 40 and 1500 m depth. In all, 37 taxa of deep-water corals were identified in the study area: 21 alcyonaceans (including the gorgonians), 11 pennatulaceans, 2 solitary scleractinians, and 3 antipatharians. The greatest diversity of coral species was on the Flemish Cap. Corals were most abundant along the continental slope, between 600 and 1300 m depth. Soft corals (alcyonaceans), sea fans (gorgonians), and black corals (antipatharians) were most common on bedrock or gravel, whereas sea pens (pennatulaceans) and cup corals (solitary scleractinians) were found primarily on mud. The biomass of deep-water corals in the bycatches was highest in previously lightly trawled or untrawled areas, and generally low in the regularly fished grounds. The information derived from bottom-trawl bycatch records is not sufficient to map vulnerable marine ecosystems (VMEs) accurately, but pending more detailed habitat mapping, it provides a valuable indication of the presence/absence of VMEs that can be used to propose the candidate areas for bottom fishery closures or other conservation measures.


2012 ◽  
Vol 81 (3) ◽  
pp. 1133-1137 ◽  
Author(s):  
R. P. Vieira ◽  
B. Christiansen ◽  
S. Christiansen ◽  
J. M. S. Gonçalves

1961 ◽  
Vol 14 (4) ◽  
pp. 540 ◽  
Author(s):  
RF Mullaly

The brightness distribution of 21-cm radiation over the Sun's surface has been studied for the past four years with the Christiansen crossed-grating interferometer (Christiansen et al. 1961) at Fleurs near Sydney. The observations described here were made using one arm of this cross as a simple grating interferometer, providing a transit instrument with a fan beam of about 2' of arc resolution to half-power points in the east-west direction and very low resolution north-south. The Sun was scanned repeatedly from east to west at time intervals of approximately 4 min.


The geographical field in which most of the Discovery Committee’s work has been carried out during the past 25 years is the Southern Ocean. This zone of continuous deep water, very rich in marine fife, supports one major industry—the whaling industry—but is otherwise little developed as yet, and seldom visited. It is not easy to find a short descriptive label for the work itself, but nearly all of it comes under the headings of deep-sea oceanography, whales and whaling, or Antarctic geography, and much of it is concerned with the interrelations of these subjects. Since the beginning in 1924 the Discovery Committee has worked under the Colonial Office, but in 1949 the Committee’s functions, together with the scientific staff, the ships, and other assets, were taken over by the Admiralty, and now form part of the new National Institute of Oceanography. The Discovery Committee, in its original form, has been dissolved, but it is encouraging to know that the continuation of its work is assured.


2018 ◽  
Vol 61 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Carlos Sangil ◽  
Laura Martín-García ◽  
Julio Afonso-Carrillo ◽  
Jacinto Barquín ◽  
Marta Sansón

AbstractExtensive offshore meadows ofHalimeda incrassataare documented for the first time in sandy bottoms of La Palma, Canary Islands.Halimeda incrassataforms dense sublittoral assemblages between 20 and 55 m, but isolated populations occur down to 65 m depth. This species currently spreads over an area of 9.14 ha. Population coverage varies with depth, with the highest values at 35–40 m and an average cover of 62.34%. The calcified segments ofH. incrassataact as a stable substratum in these soft bottoms for the growth of other macroalgae, such as the rhodophytesLophocladia trichocladosandCottoniella filamentosa. Specimens reach lengths of up to 10 cm, shorter than individuals from the Caribbean. Although it is difficult to ascertain whether this species is a recent introduction, there is evidence of a correlation between the increase in population coverage and recent ocean warming, constituting another example of the tropicalization of the marine flora of this region.


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