Marine ecologist, Dr Drew Harvell has articulated the urgent need to protect marine ecosystems, particularly seagrass meadows, in a bid to strengthen climate resilience and secure valuable resources known as “blue foods”.

In a seminar at the University of the South Pacific (USP) marine campus Monday, Dr Harvell highlighted the multifaceted benefits that seagrass meadows offer to coastal communities and the wider marine environment.

“The big project is to conserve marine ecosystems, especially those that confer benefits like blue foods or climate resilience and an ecosystem like seagrass meadows,” she said.

Emphasising the protective role of seagrass meadows during storms, Dr Harvell explained, “having a seagrass meadow means that if there are big storms, there tends to be much less erosion and there’s protection for shore-based houses and people.”

She said, “A lot of the baby fish are nurtured in the seagrass meadows, and the oysters, clams, and crabs also live in the seagrass meadows and so there’s a high value.”

Dr Harvell also emphasised the seagrass meadows’ capacity to mitigate pathogenic bacteria commonly found in sewage.

“Seagrass meadows also reduce pathogenic bacteria such as might be found in sewage, which is a problem worldwide, and is an increasing problem with coastal flooding associated with climate change.”

She shared her research showed that mussels near seagrass showed 65 percent fewer pathogenic bacteria than those without after monitoring 20 Seattle coastal sites.

“So, it’s one more value for this ecosystem that previously hadn’t really been accounted for and we’re working on adding and accounting it.”

Dr Harvell discusses about pathogenic bacteria. Photo: Sanjeshni Kumar/Pasifika Environews

However, she said that seagrass meadows are declining “quite rapidly” globally but has the potential to exist well in a slightly warmer world.

“Seagrass actually doesn’t mind more carbon dioxide. Remember, it’s a plant, it’s actually absorbing carbon dioxide. So, it is a habitat that should be able to persist well through climate change if we give it the attention it needs.”

For Pacific nations that are heavily reliant on seagrass ecosystems, Dr Harvell stressed the need for continual monitoring to grasp how these vital habitats evolve over time.

“If they’re picking up big declines, then develop conservation programmes that can protect those meadows.

“Seagrass meadows are absolutely vital in Pacific islands. They are incredibly valuable food source for fishes and also as nursery area for bigger fishes. So, they’re the nursery grounds.

“They do the same thing for many Pacific Islands, in terms of providing coastal resilience against storm damage and erosion, keeping the water clean, providing health benefits for humans, and probably for some of the biota that live in the ocean.”
She also emphasised the interconnectivity of tropical ecosystems, including mangroves, seagrasses, and coral reefs.

“Some of the fish, for example, that live on coral reefs grow up in a nursery area and the seagrass. Similarly, some of the fish that may be live as adults in seagrass grow up on mangroves. So, these are very important habitats that work together to provide food from the sea, and they also work together to reduce coastal erosion, sedimentation and pollution.”

Photo: Dr Drew Harvell/Facebook

She urged communities to reconsider their development choices when considering the installation of ports or docks against the preservation of seagrass meadows.

“When a town has to decide should I have a port or a dock in that place or should I keep my seagrass meadow? They might view that equation differently now.”

Dr Harvell outlined practical steps for communities to engage in seagrass preservation.

“The really important first step is just monitoring, and everybody can help with that. It’s actually pretty fun to do. Just go out and measure the extent of the seagrass bed and compare how it’s changing through time.

“Secondly, it’s possible to monitor the health of the seagrass, and then finally, in the case where there may be some declining beds, to really pull together to support healthy practices for the seagrass meadows, saying no, we don’t want dock there, we’d rather have a seagrass meadow, it’s more valuable over the next 10 years, that seagrass meadow is going to vastly repay us more than a dock would.”

She highlighted innovative approaches involving the introduction of more robust strains of seagrasses and identifying resilient locations for their growth.

“We’re just starting to think about ways to move in new strains of sea grasses that might be more healthy and also start to map resilient locations. Find what are the best places for seagrass and be sure we protect them,” she said.

The economic benefits of seagrass conservation were also addressed, with Dr Harvell noting that these benefits may be significantly undervalued, particularly when considering the cost of treating waterborne illnesses.

“The economic benefits are very high. I think they’re currently undervaluing the real benefits. We need to go back and do more with that,” she said.