Category Archives: In the (Sea) Grass

Randall snorkels in a seagrass bed in Saint Joseph Bay Peninsula State Park. Photo by Dr. Peter Macreadie. Peter is a researcher from the University of Technology, Sydney, who is visiting Randall and David.

What Have Seagrasses Done For Me Lately?

Episode 6: Blue Carbon Where the Stingray Meets the Horse Conch

At the beginning of September, Randall and David had a visit from Dr. Peter Macreadie of the University of Technology, Sydney.  In this video, Randall takes Dr. Macreadie for a snorkel in St. Joseph Bay.
Dr. Randall Hughes FSU Coastal & Marine Lab

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We now focus our attention to seagrasses, which as it turns out, often don’t get a lot of attention, at least in comparison to other marine habitats like coral reefs or even salt marshes.

Randall snorkels in a seagrass bed in Saint Joseph Bay Peninsula State Park. Photo by Dr. Peter Macreadie. Peter is a researcher from the University of Technology, Sydney, who is visiting Randall and David.

In part, this lack of attention is due to the fact that seagrasses typically live completely underwater, except at very low tide, and so they are not as noticeable as marshes are. In addition, seagrasses often occur in shallow estuaries not known for their great visibility (and thus not as ideal a location as coral reefs for snorkelers or scuba divers). And, although I disagree, some people just don’t find them very pretty.

Last week as I was starting to think about this post, there was a small uptick in the number of media articles related to seagrasses, at least in Australia. The increased interest was in response to a proposal by the Environment Minister, Tony Burke, to require greater seagrass protection from mining and development projects (read more in this article from the Brisbane Times). As justification for the increased financial burden on companies, Mr. Burke cited the many benefits that seagrasses provide. And just what are those?

Scallop in St. Joseph BaySeagrasses (like salt marshes and oyster reefs) provide habitat for many, many fishes and invertebrates. Studies have found that the number of animals living in seagrasses beds can be an order of magnitude higher than the number living in adjacent coastal habitats. Many of these animals rely on the seagrass beds as a “nursery” that protects them from predators until they grow larger. And lots are recreationally and commercially important species that we like to eat. (Scallops, anyone?)

Seagrasses are also incredibly productive plants, sometimes growing more than 1cm per day, and rivaling our most productive crop species like corn. Because a significant portion of this plant material (particularly the roots and rhizomes below ground) stays in place once the plants die, seagrasses can also serve as important ‘carbon sinks’, or buried reservoirs of carbon. In fact, a recent study estimates that the carbon stored in the sediments of seagrass beds is on par with that stored in the sediments of forests on land!

Although lots of the productivity of seagrass beds makes its way underground, some of it does get eaten. Major consumers of seagrasses include urchins and fishes, as well as the more charismatic dugongs, manatees, and sea turtles.

Spider Crab in St. Joe BaySeagrasses (like salt marshes) also play an important role in reducing nutrients that run off from land into the water. Unfortunately, these nutrients can also lead to the loss of seagrasses, by promoting increased growth of algal “epiphytes” that grow on the blades of the seagrasses themselves. When there are not enough small fishes and invertebrates around to eat these algae, they can overgrow and outcompete the seagrass, leading to its decline. And when the seagrasses become less abundant, the animals that rely on them are also often in danger.

The Big Bend and Panhandle of Florida are home to expansive seagrass beds that also often go unnoticed. But they contribute to the productivity, diversity, and beauty of this area in many ways, as anyone who has been scalloping recently has surely realized!

Here is a quick guide to the animals featured in the video above:
0:40 Horse conch and sea urchin joined suddenly by a stingray
1:41 Juvenile pinfish
1:18 Two shots of a bay scallop
1:33 Sea urchin
1:49 Pen shell clam covered in sea stars (2 shots)
1:56 Horse conch

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

Seagrass beds “down under”

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- habitat 150As I mentioned in my last post, I’ve spent the last 6 weeks or so on a research trip to Australia. Most of my time was spent at the University of Technology in Sydney, but for the last 2 weeks, I traveled to Port Phillip Bay (the bay that Melbourne is on) to meet with some colleagues about their seagrass resilience project. One of our days was spent snorkeling around their field sites. The video above was taken by Dr. Peter Macreadie, and it provides a great sense of just how pretty these seagrass sites are. (I make a cameo snorkeling nearby in the blue shorts.) It was chilly (~ 70 degrees in and out of the water), but it was fun to take a look around!

Lake MacQuarie, near Sydney. In Randall's last post, she describes the research they did on foundation species like oysters, algae, and clams.

 

In the Grass, On the Reef, A World Away

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biogeographic 150IGOR chip- habitat 150David and I are in Sydney, Australia, on visiting research appointments with the University of Technology Sydney. We arrived the first of the year, and after recovering from jet lag and getting our bearings, we embarked this week on setting up a couple of new experiments.  We have great local “guides” – Dr. Peter Macreadie (UTS), Dr. Paul York (UTS), Dr. Paul Gribben (UTS), and Dr. Melanie Bishop (Macquarie University) – to introduce us to the field systems and collaborate with us on these projects.

lake_macquarie

Our seagrass and razor clam experiment is set up at Point Wolstoncroft in Lake Macquarie (north of Sydney).

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Horse Conchs Rule the Seagrass Bed

In the Grass, On the Reef: Testing the Ecology of Fear

Premieres on WFSU-TV Wednesday, June 29 at 7:30 PM, 6:30 CT.  In high definition where available.

Rob Diaz de Villegas WFSU-TV

IGOR_chip_predators_NCE_100This clip is a short segment on one of the predators featured in this program: the horse conch.  It’s practically an ecosystem onto itself, as you can see in the video’s poster frame above.  Barnacles, crepidula, bryozoans, and other marine creatures that affix themselves to hard surfaces settle on its shell.  In the video you’ll see its bright orange body as it roams the seagrass beds of the Forgotten Coast.  And you’ll see it eat another large predatory snail, the lightning whelk.

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Photo Feature: Bedazzled Predator

Rob Diaz de Villegas WFSU-TV

Horse Conch shell covered in bivalves

IGOR chip- habitat 150It kind of looks like one of those vintage ’80′s jackets adorned with mirrors and sequins- mollusk style.  This horse conch’s got a little bit of everything on it, the result of an interesting reversal of roles in this seagrass bed on Bay Mouth Bar.

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