Concentrations of Nutrients and Chlorophyll on a Cross-Channel Transect in Juan de Fuca Strait, British Columbia

1978 ◽  
Vol 35 (3) ◽  
pp. 305-314 ◽  
Author(s):  
A. G. Lewis

Nutrient and chlorophyll values were measured hourly at one of four stations on a cross-channel transect, over a 25-h period during each of 5 mo. Nitrate values increased with depth, chlorophyll decreased, and phosphate remained essentially unchanged during most months. Chlorophyll and phosphate values did not show consistent cross-channel trends, while nitrate levels were frequently higher on the southern side of the Strait. The cross-channel nitrate pattern can be at least partially explained in terms of geostrophic flow; greater amounts of nitrate-rich oceanic water enter at depth on the southern side of the Strait, while nitrate poor inshore water exists near the surface on the northern side. Key words: nutrients, chlorophyll, Juan de Fuca Strait

1979 ◽  
Vol 36 (10) ◽  
pp. 1223-1227
Author(s):  
D. D. Lemon ◽  
P. H. LeBlond ◽  
T. R. Osborn

Seiche motions observed in San Juan Harbour with a bottom-mounted pressure gauge have been Fourier-analyzed and interpreted in terms of a theoretical model of oscillations in a rectangular basin with an exponential depth profile. Two of the observed periods (at 14.6 and 38.5 min) are identified with resonances of the basin; two other significant low frequency peaks (at 21 and 55 min) do not coincide with resonant periods of the basin and must be due to strong external forcing. Higher frequency fluctuations (20–160 s) are attributed to swell and to its subharmonic interactions with edge waves. Key words: water waves, seiches, mathematical model, Juan de Fuca Strait, British Columbia


1979 ◽  
Vol 16 (9) ◽  
pp. 1645-1657 ◽  
Author(s):  
Neville F. Alley ◽  
Steven C. Chatwin

The major Pleistocene deposits and landforms on southwestern Vancouver Island are the result of the Late Wisconsin (Fraser) Glaciation. Cordilleran glaciers formed in the Vancouver Island Mountains and in the Coast Mountains had advanced down Strait of Georgia to southeastern Vancouver Island after 19 000 years BP. The ice split into the Puget and Juan de Fuca lobes, the latter damming small lakes along the southwestern coastal slope of the island. During the maximum of the glaciation (Vashon Stade), southern Vancouver Island lay completely under the cover of an ice-sheet which flowed in a south-southwesterly direction across Juan de Fuca Strait, eventually terminating on the edge of the continental shelf. Deglaciation was by downwasting during which ice thinned into major valleys and the strait. Most upland areas were free of ice down to an elevation of 400 m by before 13 000 years BP. A possible glacier standstill and (or) resurgence occurred along Juan de Fuca Strait and in some interior upland valleys before deglaciation was complete. Glacial lakes occupied major valleys during later stages of deglaciation.


1971 ◽  
Vol 28 (10) ◽  
pp. 1681-1681
Author(s):  
W. E. Barraclough ◽  
R. M. Wilson

The whitebait smelt Allosmerus elongatus (Ayres) is recorded from British Columbia for the first time on the basis of three specimens from Juan de Fuca Strait caught November 2, 1969.


1988 ◽  
Vol 25 (11) ◽  
pp. 1800-1810 ◽  
Author(s):  
R. H. Linden ◽  
P. J. Schurer

High-resolution and airgun seismic-reflection mapping of the approaches to Esquimalt Harbour, Juan de Fuca Strait, reveal that offshore, sea-floor sediments consist of a widespread glaciomarine unit recognizable to the entrance of the strait. The upper part of the unit has been dated at approximately 10 000 radiocarbon years BP. An early postglacial sea-level low of at least −50 m appears to have formed a widespread unconformity. Nearshore sediments above the unconformity consist of sands, muddy fine sands, and minor gravel that were deposited in a prograding marine environment. Sediments have been accumulating off Esquimalt Harbour at a rate of approximately 1.9 cm per 100 years.


1987 ◽  
Vol 65 (9) ◽  
pp. 2202-2209 ◽  
Author(s):  
John R. Holsinger ◽  
D. Patrick Shaw

Stygobromus quatsinensis, a new species of subterranean, freshwater amphipod crustacean, is described from caves on Vancouver Island, British Columbia, Canada. This is the 3rd stygobiont amphipod recorded from Canada and the 11th member of the genus Stygobromus to be found in localities north of the southern limits of Pleistocene glaciation. Stygobromus quatsinensis is a member of the hubbsi group, an assemblage of closely similar stygobiont species previously recorded from the central and western United States south of British Columbia. Two alternative hypotheses are proposed to explain the presence of S. quatsinensis on a glaciated island separated from the mainland by marine straits. One theory suggests that it evolved from putative ancestors that were present on the island before development of the Juan de Fuca Strait in the Eocene. The other suggests that it gained access to the island from the mainland through interstitial routes in coarse sediments of the Quadra Sand which infilled parts of the Georgia Strait in the late Pleistocene. Both theories assume that this species has survived glaciation in subglacial groundwater refugia.


1993 ◽  
Vol 71 (3) ◽  
pp. 519-521 ◽  
Author(s):  
B. J. van der Kamp

Records of uredinia and telia production on the alternate hosts of Cronartium coleosporioides in British Columbia and inoculation of Castilleja miniata with aeciospores collected from various locations showed that rust isolates from dry areas of the interior of British Columbia do not produce uredinia and may have lost the ability to do so. Collections from somewhat wetter areas produced uredinia or mixtures of uredinia and telia immediately following aeciospore inoculations, and field collections from such areas in June commonly had mixtures of uredinia and telia. Loss of the uredinial stage may be a response to climates that are often unsuitable for the spread or survival of the rust on the alternate host. Key words: stalactiform rust, uredinia, telia, rust life cycle.


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