Seagrass ? humans don't like to walk on it, but turtles treat it like a delicious aquatic salad bar. Seagrass is vital to the welfare of many of Bermuda's marine animals, which is why a recent decline in seagrass beds around the Island is alarming scientists.

A group of marine biologists from Bermuda and abroad started a monitoring programme this summer to nail down the rate of decline, and the source of the problem.

The project was spearheaded by Government Conservation Officer Dr. Sarah Manuel, Dr. James Fourqurean, associate professor at Florida International University, Dr. Judson Kenworthy from the Centre for Coastal Fisheries and Habitat Research in North Carolina, and Dr. Kathryn Coates, researcher for the Bermuda Government.

There are four types of seagrass that grow in Bermuda, Turtle Grass (Thalassia testudinum), Manatee Grass (Syringodium filiforme), Shoalgrass (Halodule wrightii) and Paddlegrass (Halophila deciprens).

"At the moment we are mapping the Bermuda platform," said Dr. Manuel. "We have 200 sites around the platform. We are going out and putting survey tape down which is 50 metres. We go down and put down ten quadrates along each of the 50 metres. We look at what is in there."

Researchers take note of algae, seagrass, corals and sponges in the different quadrates. They will go back and re-survey these sites every four months.

"As far back as 2004 the Biodiversity Project noticed that the offshore seagrasses were in decline," said Dr. Manuel. "We knew we had a problem when we did the survey in 2004, and then looked at aerial photographs taken in 1997 and found the offshore beds had disappeared totally in some places and in other places they were definitely receding."

Dr. Coates obtained an environmental grant from the Bermuda Government to put together a meeting which included Dr. Fourqurean and others to workshop and discuss what needed to be looked at it.

At the forum, scientists realised that the seagrass problem in Bermuda was different from seagrass declines in other places.

"In most places in the world, when seagrasses have declined, it is because of the increase in nutrients in the water due to pollution," Dr. Fourqurean said. "That has happened in the salt ponds in New England. When you increase nutrient availability in the water the seaweeds take over from the seagrasses, and the seagrasses are killed or shaded out.

"When we came to Bermuda in 2004 it was obvious that that wasn't what was happening. The seagrasses adjacent to the high density populations in Bermuda are relatively stable except for these patches where boat moorings do damage due to the scouring of the boat chain. There have been some small changes inshore, but not the drastic declines that are occurring offshore."

Finding what is causing the decline in the grass beds offshore is the scientists current focus ? but at the moment it remains a mystery.

Seagrass blades produce oxygen like any other green plant. They are a favourite source of food for turtles, fish and sea urchins. Conchs will eat algae that grows on the seagrass blades.

"They are an important habitat," said Dr. Manuel. "Spiny lobsters and many juvenile fish will actually start their lives in the seagrass beds and then move off to the reef and that includes groupers, yellow tail and snappers, among others. The seagrass meadows also help to hold the sand sediment in place, and that is good for the coral reefs, because corals can't cope with high amounts of sediment in the water."

According to Dr. Kenworthy, when seagrass beds are lost it can cause great upheaval on the seafloor.

Dr. Fourqurean does not think that hurricanes were the cause of the shrinking offshore seagrass beds.

"Seagrasses in the Caribbean evolved with hurricanes and they are still there," he said. "After a hurricane I am always more struck by the resilience of the seagrass beds than anything else. There are places that are scoured but it tends to be relatively small."

Seagrass beds tend to be more damaged by hurricanes if they have already been damaged by man. It takes about a minute for a boat propeller to cut a channel through the seagrass in too shallow water, and about 15 years for the seagrass bed to recover the channel. In the meantime the channel creates a weak spot for wave action to wear away.

According to Dr. Fourqurean, seaweeds and seagrass are two separate entities.

"Seaweeds are algae, and algae is evolutionarily ancient," said Dr. Fourqurean. "Seagrasses are flowering plants and evolved 100 million years ago so they are relatively young. The monocots started off on land, and probably went into fresh water and then into the marine environment."

Dr. Fourqurean said that the most common type of seagrass in Bermuda, turtle grass or thalassia, grows as deep as ten metres locally. In Florida it grows much deeper because the water can be clearer and there is more sun year round.

Although Dr. Fourqurean currently lives in Florida, he actually lived in Bermuda for two years as a child.

"I had the great fortune of going to school in Bermuda," he said. "I went to Warwick Academy for two years. I spent a lot of time wandering the seashore along the North Shore, scaling Abbot's Cliff down to Cockroach Island. My father worked on the Navy base at the time. I spent two years in the wonderful playground of Bermuda. It ignited my interest in marine biology and I managed to turn that interest into a career."

When the team discovers the source of the seagrass decline, the next step will be looking at ways to reverse the trend.

"The success of restoration of seagrass meadows varies," said Dr. Kenworthy. "There are few really good success stories. The thing to think about in advance of restoration is attacking the problem that might be causing the decline. There are ideas about what might be going on but we won't be able to do anything until this monitoring programme gets some data that will better allow us to look at trends and patterns out there. If you tried to go out there and plant seagrass it would be like putting a salad bar out there. Turtles, parrots fish and other marine animals that move off the reef at night would eat it."

The monitoring project is funded by the Bermuda Government, but the project is looking for more financial backing. At the moment they have a freezer to store seagrass blade samples, but no money to actually analyse the samples. Once funding is found, the seagrass samples will be sent to Dr. Fourqurean's laboratory in Florida for further research.

For more information on the project contact Dr. Manuel at the Aquarium at 293-2727.