Benthonic Algae — SCAGEL 
527 
upper portions of the intertidal zone are shown 
in Figure 43. The number of times (and per 
cent) these levels are exposed (Fig. 44) and 
submerged (Fig. 45) are also presented in an 
attempt to indicate possible critical levels. The 
tide levels are referred to in feet above or below 
the datum (zero point) which, for the coast of 
British Columbia, is the level of lowest normal 
tides. 
Chemical Characteristics 
During the summer months, when plant pro- 
duction is at its peak in Queen Charlotte Strait, 
the surface zone may be supersaturated with 
oxygen; values in excess of 15 mg/1 are fre- 
quently encountered. The maximum values gen- 
erally prevailing near the surface and to a depth 
of 20 m. are between 7 and 10 mg/1. During 
the summer months the values are somewhat 
higher than in the winter. The maximum con- 
centration of oxygen occurs at a depth between 
2 and 5 m. (Figs. 46, 47), rather than right 
at the surface during the summer, and is related 
to the region of maximum phytoplankton activ- 
ity. The water throughout most of the Strait 
has a higher oxygen content near the surface 
(Figs. 46, 47) than in Queen Charlotte Sound 
or in the adjacent connecting mainland chan- 
nels. Although marked fluctuations occur locally 
in the upper 10 m., the general picture is more 
stable (Figs. 13-17) at greater depth. 
Phosphate concentrations (PO4-P) are not 
available for the winter months, but for the 
summer, during which minimum amounts are 
probably reached, the values present (Fig. 48) 
were between 0.5 and 2.0 mg.-at. per liter in 
the upper 20 m. The minima were generally 
in the upper 10 m. and most of the minima 
for the Strait and Queen Charlotte Sound were 
between 1.0 and 1.5 mg.-at. per liter. 
BIOLOGICAL CHARACTERISTICS 
Biological observations, extending over the 
length of the coast, indicate that there is a high 
degree of uniformity in the populations of many 
benthonic plants and animals extending from 
the Strait of Juan de Fuca to Dixon Entrance. 
This would be anticipated under such relatively 
uniform conditions of temperature. In attempt- 
ing to correlate the distribution of some of these 
organisms with salinity characteristics, as well 
as other oceanographic factors, there are several 
areas on the coast which could be used for pur- 
poses of this study. Although some supporting 
observations have been made in the Strait of 
Juan de Fuca and Dixon Entrance, this paper 
is restricted largely to a consideration of the? 
vicinity of Queen Charlotte Strait near the north 
end of Vancouver I. 
Horizontal Distribution of Organisms in 
Queen Charlotte Strait 
Biological observations have been made 
throughout the area although a more intensive 
study and collection has been undertaken at 
Hope I., Deer I., and in the vicinity of the 
Keogh River, the Klucksiwi River, and Malcolm 
I. These areas present a transition from Hope 
I., where the highest salinities are encountered, 
to the north and east sides of the Strait, where 
lowest salinities are found, with Deer I. and 
Malcolm I. being intermediate between these 
extremes. The distributions in the Strait of the 
more conspicuous organisms (Table 1) observed 
during this study are illustrated in Figure 49- 
Although both the marine algae and the in- 
vertebrate animals have been observed, the em- 
phasis in this study is on the more conspicuous 
marine algae. 
Some organisms in the area are more cos- 
NUMBER OF DAYS CONTINUOUS EXPOSURE (1953) 
JANUARY fEBRUARY 
AUGUST SEPTEMBER , OCTOBER NOVEMBER DECEMBER 
pniTTT FTTTTTTTTTTn nr 1 
FIG. 43. Diagram showing number of days various levels in the intertidal zone were subjected to contin- 
uous exposure. 
