NATIONAL NOTEBOOK: Rancho Palos Verdes; Harcourt Sinks Marineland
LEAD: WHEN Harcourt Brace Jovanovich bought California's oldest aquatic park last December, admirers of Marineland hoped that its past glories might soon be restored. At the time of the purchase, the Florida-based conglomerate said it had no plans to close the 33-year-old oceanarium, even though it was run-down and barely breaking even.