This week on WGCU TV

. Jean-Michel Cousteau: Ocean Adventures - Sea Ghosts - Wednesday, April 8, 8 p.m.

Beluga whales are intelligent mammals that use one of the most complex sonar systems. Cousteau travels with his team to the high Arctic to determine why some Beluga groups are thriving and others are disappearing.

. American Masters Glass: A Portrait of Philip in Twelve Parts - Wednesday, April 8, 9 p.m.

An eventful but typical year in the career and personal life of the distinguished composer Philip Glass.

. Mystery! Miss Marple: A Murder is Announced - Parts 1 and 2 - Thursday, April 9, 9 p.m.

A "pretend" murder at the home of Letitia Blacklock goes awry when Letitia is nearly killed and her assailant commits suicide.

. Connect! Living Green - Friday, April 10, 8:30 p.m.

Sharing sustainability tips for family living; discovering practical ways to both enjoy and conserve water in your yard; and retrofitting your home to optimize energy efficiency. Hosted by Jim McLaughlin.

. As Time Goes By - Nothing To Fear But Fear Itself - Saturday, April 11, 9 p.m.

Judith wants a country wedding. Alistair is stricken with panic, and Stephen receives a great honor.

. Nature - Andes: The Dragon's Back - Sunday, April 12, 8 p.m.

When this great spine-like mountain range rose from the sea, it created a new continent that joined North and South America, allowing flora and fauna from each to mix and diversify. Today, the Andes continue to evolve as a rich tapestry of environments.

. American Experience - We Shall Remain: After the Mayflower - Part 1 of 3 - Monday, April 13, 9 p.m.

Decades of English immigration and lethal epidemics brought the Wampanoag and their native allies to the brink of disaster in the 1600s.

. NOVA - Doctors' Diaries - Part 2 - Tuesday, April 14, 8 p.m.

The last installment in the groundbreaking NOVA series that began in 1987 and followed seven students starting out at Harvard Medical School.

. Frontline/World - Tuesday, April 14, 9 p.m.

Children of the Taliban The increasing power and influence of a new branch of the Taliban in Pakistan is investigated; then it's on to South Korea, the edge of the digital frontier.

. Great Performances at the Met - Lucia di Lammermoor - Wednesday, April 15, 9 p.m.

Anna Netrebko plays the fragile heroine of Donizetti's opera, presented as a Victorian ghost story.