On World Wetlands Day, plastic is a growing issue in our Tamar Islands

The day is celebrated every year on February 2 to mark the signing of the Convention on Wetlands in 1971, in the Iranian city of Ramsar.

Often described as the kidneys of the river because of the filtering process they provide, wetlands are also an important nursery for birds and fish.

Tamar NRM project officer Megan Grant said in our Tamar Island Wetlands, plastic was an increasing problem.

"A few years ago the University of Tasmania did a study about the pacific gulls that roost along the boardwalk here," Dr Grant said.

"They produce what's called a bolus, which is a pellet that they regurgitate; it contains things from their diet that's indigestible."

The pellets should contain things like fish bones and shells, but what they found was much worse.

"We increasingly found plastics, metal and glass and all sorts of things," Dr Grant said.

"In that study, we looked at about 450 boluses and found plastics in about 90 per cent of them."

Tamar NRM project co-coordinator Kirsten Seaver said plastics didn't break down, but broke up into smaller pieces.

"This is the message that we're trying to drive with practically all work we do, is that plastic will eventually get to the point where it's a nano-plastic," Ms Seaver said.

"We're ingesting it and we're breathing it, and so all the animals."

She said it was important to understand what wetlands provided as an ecosystem.

"They're actually great carbon sinks, everyone thinks they have to plant trees and yet wetlands provide a massive carbon sink," she said.

"We have to look again at the values that wetlands provide.

"They also filter out a lot of stuff before they get into the river system or the estuary."

The Tamar Island Wetlands Centre will be celebrating the wetlands for the rest of February each weekend, with a range of free activities to mark the occasion including Tai Chi, educative workshops and more.