Our Changing World - Waituna Lagoon and 'Flipping Lakes'

Many lakes and rivers around New Zealand are suffering from the effects of too much sediment and too many nutrients. In Southland, attention is focused on declining water quality in Waituna Lagoon, with fears that this unique coastal lagoon may be about to 'flip'. To find out what 'lake flipping' is, Alison Ballance visits the lagoon and meets some of the experts.