Darwin's mangroves: research investigating impact of unprecedented sea level rise
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The first time Madeline Goddard stepped into the dark fudge underneath Darwin's mangroves she turned into "a human bog".
"I actually got so deeply stuck that it took two people to pull me out," Ms Goddard said.
"And I lost both of my shoes."
In the past six months the honours research student has bought a pair of mud-wading boots and developed ways of moving through the precarious mangrove forests.
She has also seen the Top End's celebrated coastal wetlands grapple with some of the highest rates of climate change related sea level rises in the world.
Darwin Harbour's 20,000 hectare mangrove estate houses 37 types of the terrestrial plant, as well as many species of crabs, fish, snakes, birds and other wildlife.
Scientists believe the intricate mangrove forest ecosystem, up-ended roots embedded in layers of thick mud, can respond to changing sea levels through a process called "building land".
This process involves the gradual build-up of leaf litter, dead animals and other organic matter, so that the mangrove trees can stay above water.
The resulting sludge is incredibly carbon-rich, jet-fuel black, and pungent about a metre below the sediment's light brown surface.
"I find the smell quite neutral unless you step in really deep," Ms Goddard said.
"Then you get into the sulphur anoxic black mud and it smells like eggs."
Ms Goddard spends a few days each month in the mangroves with long mud-measuring sticks as part of a pioneering worldwide study looking at vulnerable coastal regions.
Her ongoing research aims to find out whether Darwin's mangroves are surviving the region's 8.8 millimetre annual sea level rises.
She said it is "currently unclear" whether the Top End's mangroves are continuing to "build land" and stay afloat in the face of such unprecedented environmental change.
If they are not responding well, the results could be devastating.
"The mangroves [are] not just an area that sits between Darwin and the water," she said.
"There's a huge number of fish that rely on them for their nurseries and they also provide some protection from coastal erosion."
The mangrove's muddy root systems are also important due to their ability to soak up noxious CO2 from the Earth's atmosphere and store it indefinitely as carbon.
Ms Goddard's research additionally hopes to quantify the Top End mangroves' carbon sinking ability, so that more is known about their environmental benefits.
"I think it's really important that we protect our mangroves," Ms Goddard said.
"In the last 60 years, we've lost 50 per cent of the world's mangroves.
"Overseas, they're [now] looking to protect the mangroves [because] they are so amazing at sinking this carbon. There is nothing like that in Australia.
"It's a pretty amazing environment. When you hold still, and watch and listen, you notice that the [mangrove] floor is alive.
"There's all these roots sticking up [and] you'll see crabs in a whole variety of colours.
"And lots of mud skippers hoping around [that] are cute and curious."
But Ms Goddard does not think she will ever become "100 per cent" at home in the mangroves.
"It always feels pretty foreign. It's very muddy and difficult to move through, but I feel I've gotten a bit better at moving through it than on my first day.
"Since then, I've had no shoe incidents [and] learned a few tricks to move through this environment.
"You've got to keep moving. When you stop, you sink, so you've got to lift your knees really fast and keep your motion forwards.
"That's all I can say. Good luck."
Topics: environmental-impact, climate-change, research, environmental-management, darwin-0800
