Benthonic Algae- — SCAGEL 
523 
then fall to a lower temperature again, beneath 
this warmer upper layer, down to between 6° 
and 7°C. in the deeper regions. 
Thus the environment presented to the inter- 
tidal and immediate subtidal zones (see Fig. 25 
for terminology) appears to be a relatively 
stable one as far as the temperature of the sea- 
water is concerned. 
Meteorological Conditions 
The intertidal region, however, during periods 
of exposure, is subjected to a varying degree to 
meteorological conditions, particularly fluctua- 
tions in temperature and precipitation, which 
must be considered in assessing the environment 
of organisms in this region. A comparison of 
the meteorological data (air temperatures, pre- 
cipitation, mean relative humidities, and mean 
cloud cover) available for the coast of British 
Columbia, particularly from Bull Harbour 
(Hope L) , Hardy Bay, and Alert Bay, gives 
some picture of the meteorological conditions 
at the northeast end of Vancouver L (Figs. 
26-37). 
Along the coast, air from the maritime Pacific 
Ocean is usually present and results in mild 
winters and cool summers. Holding a high mois- 
ture content, this air does not become extremely 
hot or cold. However, occasional outbreaks of 
continental air (polar) from the interior of the 
1353 
Fig. 38. Monthly summary of tidal features at Hope Island for 1953 (see Figure 39 for significance of lines). 
