Published On: Mon, Mar 14th, 2016

R/V Chapman Expeditions & Substation Curaçao

WILLEMSTAD. ROSSEAU - It can be difficult to describe the underwater world from 300-1,000ft, as habitats can be as varied as anything you could see on land. Not every inch of bottom is covered in coral and fishes; there are many areas where you only see vast stretches of sand, silt, and rocky outcrops with seemingly little life.

Smithsonian scientists know that things are not always as they seem. Based on recent studies, biodiversity scientists estimate there are between 10-14 million living species on the planet and only about 1.2 million have been documented! Even in areas that look bare, a small rock pile or sponge can create surface area or habitat for a diverse array of organisms.

Over the past week here on Dominica, Smithsonian DROP scientists encountered numerous dark, vertical, one- to three-feet long, tube-shaped sponges with lots of finger-like projections. ” They did not recognize the sponge and gave it the nickname “The Rasta Sponge.” But they could see from the window of the Curasub that there was something special about them. They were covered with other life.

Dr. Darryl L. Felder, a specialist in decapod crustaceans equates this naturally occurring ecological assemblage to collections made by the ongoing Smithsonian ARMS (Autonomous Reef Monitoring Structures) investigation currently underway on Curacao since 2012.

At the surface, DROP scientists found that the sponge served as a foundation for a diverse community of invertebrates and fishes. Their team, led by DROP Principal Investigator, Dr. Carole Baldwin, estimates there were hundreds of species in a single sponge. They documented small solitary corals, hydroids (predatory polyps), bryozoans, nudibranchs (sea slugs), bristle worms, peanut worms, crabs, shrimps, and gobies living on or inside it. You can see images of some animals in the gallery below; most are under 3cm in length.

Sponge Specimen Gallery CAPTIONS

Spiky Sponge

Hydroid (Aglaopheniidae sp.)
Size: less than 1 mm
Hydroids are predatory polyps that form colonies on substrate like rocks and artificial structures. They are related to jellyfish, anemones, and corals.

 BristleWorm_AGC_6861 copy


Unknown Bristle Wrom (Polychaeta)
Size: 8mm
This worm has tufts of bristles or setae protruding from its sides. These needlelike hairs help protect the worm from predators.


CockatooWorm_AGC_6842 copy

Ampharetidae (Polychaeta)
Size: 3cm
This annelid worm was dubbed the “Cockatoo Worm” by the field team because the elaborate tentacles near the head resemble the head plumage of a Cockatoo bird.


Eunicidae_AGC_6532 copy
Eunicidae Rock Worm

Eunicid worms are enormously diverse, being found in nearly all marine environments. The dark spots on the head are eyespots. 


Hesionid from Spiky Sponge copy
Hesionidae Worm

Size: 1cm
This segmented worm has parapodia on each segment that are used for locomotion.



Sipunculida_AGC_6647 copy

Unknown Peanut Worm
Size: 1cm
Peanut worms have a retractable proboscis


SpaghettiWorm_AGC_6870 copy


Unicorn Worm_Eunicidae_Dominica_8cm.jpg


Undescribed goby fish

Size: 1 cm or smaller

Gobies are the most diverse family of marine fishes, and live in or on stationary organisms such as sponges, corals, and urchins.


Many marine organisms prefer to live on hard substrates. With the bottom dominated by silt, the sponges offer a potential home. Many sponges engage in chemical warfare to keep other organisms off them. But the Rasta Sponge is a big push over. It provides space for many other organisms to live, feed, or hide. Many of the rarely encountered animals found on these sponges are poorly known or new to science.

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