Our underwater forests are key to fighting climate change, but the kelp needs our help
As you line up to start the 8.4km Round the Bays race, it might be hard to think of anything except the run ahead of you. How much you’ve trained, how ready you are, how close to your goal you might get, how many children you need to wrangle alongside you as you walk, jog or sprint along Tāmaki Makaurau’s coastline.
But somewhere between Spark Arena and St Heliers Bay, spare a thought for the forests that grow in the Hauraki Gulf, beneath the crashing surf. Think about the kelp.
Dr Caitlin Blain thinks about the kelp almost all the time. From the University of Auckland’s Marine Laboratory in Leigh, Blain researches where kelp fits into coastal carbon cycles and how it might play a part in slowing down or stopping climate change.
Kelp is a seaweed. All going well in its ocean habitat, it grows in gorgeous plumes of forest that sway captivatingly with the currents, housing thousands of species between its soft brown branches.
But kelp is in trouble. Whether it’s our warming climate heating the ocean, or extreme weather events sending tonnes of silt into the sea – or a whole host of other stressors – kelp needs our help to survive.
And we need kelp too, Blain says. Her research has shown that kelp forests sequester carbon dioxide from the atmosphere as well as any of our on-land forest. Her next questions are about just how well they perform.
“We're obviously trying as a community and across the world to reduce our carbon dioxide emissions,” Blain says.
“One of the most simple ways to help mitigate the emissions that we've already put out there is by enhancing our natural environment and enhancing those ecosystems that can naturally remove carbon dioxide.
“We see a lot of tree-planting that goes on around different areas and that's to help sort of increase our carbon drawdown, and it’s the same in the water. We want to quantify how much that kelp can really draw down.”
Blain and her team have a laundry list of questions to answer about kelp, including figuring out what has, historically and today, been causing kelp to decline, and what we need to do to restore it.
And unlike our on-land forests, restoration isn’t as simple as planting more trees.
One key problem the kelp of the Hauraki Gulf faces is sediment clouding the water and blocking its sunlight; that essential ingredient that keeps everyone happy and keeps our plants photosynthesising.
We need kelp to photosynthesise and convert carbon dioxide from the atmosphere into oxygen, so the ocean darkening above it should worry us, Blain says.
“When there's rain or different sorts of weather events and storm activity, the land erodes slowly, that’s a natural sort of occurrence.
“But as we've manipulated the land through developing cities, developing farmland, taking away the trees, the resilience of the coast gets diminished and it becomes a lot easier for it to erode because it doesn't have that kind of structural integrity any more.”
When you combine that with the extreme weather events associated with climate change – think the Auckland Anniversary Weekend flooding and Cyclone Gabrielle of summer 2023 – it’s a sure-fire way to get extra erosion dumped into coastal marine areas, blocking the light from the life beneath it.
Then there is overfishing, smashing up shallow reefs or snapping up the fish that eat sea urchins, which, if left to their own devices with no predator in sight, will decimate the kelp in the Hauraki Gulf, Blain says.
But we don’t need to be too despondent, because there is power to reverse or slow down kelp degradation, Blain says, whether you’re on the coast or not.
“Everything we do affects the environment and nothing works in isolation. The land we live on is connected to the sea, so any little things that we can do might seem arbitrary to people, but they can make a big difference when we add them up. Whether it's taking care of your rubbish or your recycling, helping plant trees or getting involved in community initiatives that are set out to kind of enhance the environment.
“I think people just need to get involved in ways that they can and that work with their life. It can feel overwhelming when you feel like you're trying to do it all by yourself.”
One way to join a team effort is to Run4TheGulf - joining Live Ocean’s Round The Bays team. All proceeds from team entry fees go towards their partner research like Blain’s.
The land we live on is connected to the sea, so any little things that we can do might seem arbitrary to people, but they can make a big difference when we add them up.
Dr Caitlin Balain