For 10 points, name these variations in the sea level.
Arthur Doodson designed a machine for predicting the magnitude of these events. They occur in a cycle that includes "stand" periods followed by "slack water" periods. An unusually high concentration of dinoflagellates (DYE-no-FLADGE-ell-ates) can cause the "red" type. Weak versions of these events are known as "neap" ones and occur in the first and third quarters of the lunar cycle. For 10 points, name these variations in the sea level.
Arthur Doodson designed a machine for predicting the magnitude of these events.
tides