Concept:
For a gas bubble, assuming temperature remains constant, Boyle's law is applied:
\[
P_1V_1=P_2V_2
\]
Step 1: Depth of lake is:
\[
90\text{ m}
\]
Step 2: Atmospheric pressure is equivalent to:
\[
10\text{ m of water}
\]
Step 3: Pressure at the bottom of the lake:
\[
P_1=90+10=100\text{ m of water}
\]
Step 4: Pressure at the surface:
\[
P_2=10\text{ m of water}
\]
Step 5: By Boyle's law:
\[
P_1V_1=P_2V_2
\]
\[
100V_1=10V_2
\]
\[
V_2=10V_1
\]
Step 6: Therefore, the volume becomes \(10\) times.
\[
\boxed{10\text{ times}}
\]