A World Adrift: Life in the Sargassum Slideshow

Smithsonian Marine Science Network Postdoctoral Fellow, Seabird McKeon, returns from the Smithsonian field site in Belize. Together with Dan Barshis of Stanford University, Seabird reports on the seemingly invisible inhabitants of drifting sargassum seaweeds. As with many parts of the ocean, a ball of sargassum is more than meets the eye. Check out his blog post to learn about the world adrift.

Tags: 
Coasts, Camouflage, Feeding, Smithsonian scientists, Seaweed
A juvenile swimming crab sits on a bed of sargassum seaweed. Brown grass shrimp on a floating piece of seaweed.

Shrimp hides in the sargassum

The shrimp Latreutes fucorum is perfectly colored to hide on the leaf-like blades of the sargassum. That could be why they are popular members of the seaweed community. Dive in to see more creatures hidden in this drifting habitat.

Credit: 

Seabird McKeon

Floating Sargassum Seaweed

Sargassum fluitans, a.k.a. “Gulfweed,” forms dense clumps up to the size of a beach ball that slowly rotate as they drift. The fronds are quite dense, but if you look carefully, sometimes you can see hints of the rich community that hides in the floating sargassum.

 

 

 

 

 

Credit: 

Seabird McKeon

Tiny crab in the sargassum

The sargassum is coated with encrusting organisms, such as bryozoans and hydroids, that use it as a perch to filter feed in the oceanic waters, as well as crustaceans such as the swimming crab Portunus sayi.

Credit: Seabird McKeon
A juvenile swimming crab sits on a bed of sargassum seaweed.

Adult Swimming Crab

When they get larger, Portunus sayi are formidable predators, quick to consume any smaller animal that comes within reach.

Credit: Seabird McKeon

Juvenile plane-head filefish

Relatively slow moving, juvenile plane-head filefish Monacanthus hispidus (Monacanthidae) travel along with the algae. They pick off and eat small animals as they move around in the rotating sargassum ball. Adult filefish only grow to be about 11 inches long.

Credit: Seabird McKeon

Seaslug Camouflages in Seaweed

Winner of the ‘best camoflauge’ contest, the nudibranch Scyllaea pelagica is usually betrayed only by its motion. Along it’s back, the sea slug has growths called papillae that help its masterful disguise. The papillae resemble the sargassum's own hydroids that these sea slugs love to graze.

Credit: Seabird McKeon
Brown grass shrimp on a floating piece of seaweed.

Brown Grass Shrimp

Another common species of sargassum shrimp, Leander tenuicornis (Palaemonidae) can be spotted by its long transparent claws or "chelae". Very similar shrimp are found in near shore habitats all around the world. Using genetic tests we may determine if they are the same species, or two different species that look the same.

Credit: Seabird McKeon

Sargassum Frogfish

The sargassum frogfish Histrio histrio is a small but voracious predator - it can ingest animals up to it’s own size! The fins of the frogfish are perfect for creeping around in the algae and stalking unsuspecting prey.

Credit: Seabird McKeon

Frogfish Histrio histrio

The Sargassum frogfish Histrio histrio is a small but voracious predator - it can ingest animals up to it’s own size! The fins of the frogfish are perfect for creeping around in the algae and stalking unsuspecting prey.

Credit: Seabird McKeon