Admin users can decide how often the workspace sends email notifications from the workspace. Users have the ability to override the default settings for their own profile.
How to do it (admin)
Go to workspace settings > Notification settings.
Set "What's new summary email frequency" to "never"
Deselect personal notifications
With these settings there will be no automated emails to workspace participants.
Note: notifications will still be shown in the notification centre when logged in to a workspace.
How to do it (participant)
Open your personal menu at the top right corner of your screen
Open your profile
Navigate to notification settings
Disable the option "Send email notifications on workspace updates"
Note: As with the previous case, notifications will still be shown in the notification centre when logged in to a workspace.