If you value clean water and kaimoana, you should care a whole lot more about our soft-sediment communities, i.e. shelllfish and crabs living in sand and mud.
These creatures are big players in protecting sensitive habitats - they mix it up, add oxygen to it, and when they're not in the right balance things like algal bloom can thrive.
Conrad Pilditch from the University of Waikato is working to understand how the major stressors in coastal environments - nutrient and sediment inputs from land - are affecting the biodiversity in estuarine and coastal habitats.
He talks with Kathryn Ryan.