Recyclers of the coastal zone

Argo deployment reaches new milestones

Dr Drew Lohrer setting up benthic chambers on Waitemata Harbour sandflats. (Photo: Luca Chiaroni, NIWA)

Worldwide, there is growing recognition of the services nature provides that effectively sustain life and business on our planet. NIWA research is highlighting the vital services provided by estuarine ecosystems and the threats they face.

Estuaries act as filters and recyclers: processing nutrients, contaminants, and sediments that are washed off the land. By cycling nutrients, seafloor ecosystems can supply up to half the nutrients for primary production in coastal waters, supporting fisheries, shellfish production, and shorebirds.

We are researching the role key seafloor species play in processing these inputs, and what happens when they become overloaded. Species like horse mussels, heart urchins, and cockles help release nutrients from the seafloor and create habitats for other species. Seagrass and large shellfish also provide nurseries for juvenile fish. “Because of feedback mechanisms, small changes in the abundance of such key species can rapidly alter an estuary’s ability to process nutrients and contaminants,” says Dr Simon Thrush, who leads NIWA’s coastal ecosystems research.

This research, funded by the Foundation for Research, Science & Technology, will help coastal managers devise policies and strategies that avoid damage to estuaries and maintain the important ecological services they provide.

“Understanding how seafloor ecosystems function and respond to disturbance will also help assess likely effects of climate change,” says Dr Thrush. “Our coasts and estuaries are on the frontline in terms of climate change impacts, and research on their likely response is urgently needed.”

Research subject: Oceans