Scientists work around fangs and jellyfish to restore lost seagrass

Restoring a seagrass meadow in far north Queensland can be a bit like trying to garden on a lawn full of deadly snakes and spiders – you wouldn’t set foot there.

It’s the equivalent of those dangers faced by scientists at James Cook University as they test new techniques to restore a seagrass meadow in Mourilyan Harbor south of Cairns, home to crocodiles. and deadly jellyfish.

“We knew we were going to have to be able to deploy this from a boat because we can’t get into it in the water,” Associate Professor Michael Rasheed said.

Scientists from James Cook University, the Aboriginal Rangers of Manduburra and volunteers work together to restore seagrass beds.(Provided: JCU Cairns Campus)

This excluded options offered by previous successful restoration trials, such as diving to plant seagrass sprouts or seeds.

“That’s why we put things on frames that we can lower from the boat and drive them into the sediment without having to get into the water,” Dr Rasheed said.

“What you need is something to anchor the grafts in place. There are a lot of flowing currents, tidal currents and wind currents.”

Last year, scientists first tried to deploy 12 metal frames, with seagrass sprouts attached, in the harbor.

Three of the planters successfully survived the year and the growth spread.

However, metal frames create more work as they have to be removed from the environment later.

Mesh with seagrass above.
A biodegradable trellis is used to anchor the seagrass fragments.(Provided: JCU Cairns Campus)

“We are now testing biodegradable mesh that we can leave there,” said Dr. Paul York, marine and estuarine ecologist.

“Once the seagrass has established itself, it will slowly decompose and compost on the site.

“In addition to that, we also attach individual shoots to stones, boulders and nails and scatter them around the meadow.”

Dr Rasheed wants the importance of seagrass beds to be as well known as the Great Barrier Reef and the humid tropics of World Heritage.

People in a laboratory fill buckets with sea herbs.
Scientists and volunteers cut fragments of seagrass for planting.(Provided: JCU Cairns Campus)

La Nina weather events that cause loss of seagrass, excessive rains and increased frequency of cyclones are expected to become more frequent.

JCU scientists predict that their groundbreaking success could see the methods they use adopted internationally as seagrass restoration becomes more necessary.

Ms Orjuela said that so far she has focused on conservation.

“Last year I dealt with a very interesting topic which was restoration ecology, so it increased my interest in the type of project that we can give a little more to,” she said.

“Maybe we can start looking for restoration projects that we can start, taking a step forward to recover some things that we had before.


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Chris B. Hall