Hydrothermal Vents are oceanic hot springs in volcanically active areas; they are mostly deep and along the midocean ridges (but sometimes are shallow, e.g., near Iceland or volcanic islands in the Mediterranean). At these vents, hot (up to 400C) mineral-laden water provides abundant energy, mostly as H2S (rotten-egg-smelling hydrogen sulfide). Eubacteria and archaea use H2S for energy, again being the basis of the food chain. Similar clams, mussels and tubeworms with symbionts are found here. The microbes use a process called chemosynthesis (see ONR site for more information). Limpets, snails and other worms graze on microbial mats and filaments. Fish, octopods and crabs are probably carnivores and scavengers.
FAR ABOVE: chimney being collected with Alvin claw JUST ABOVE: the chimney on the ship, broken open to reveal lining of IRON PYRITE (Fool's Gold) crystals		Chimneys/Towers at Faulty Towers
Smokers				Snails on tower	Snails	Ridgeia close-up	Ridgeia "bush"

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•MAIN ENDEAVOUR SEGMENT of the Ridge; 2.2 km deep; HULK and DANTE edifices

Black Smoker		White and black smoker chimneys with tubeworms			Scenes of lava formations near the Main Endeavor vents
White smoker	Alvin sampling the black smoker water	Ridgeia tubeworm colonies (and orange bacterial mat, left)			Close up of limpets and snails inside worm colony	Crab and rattail (grenadier) fish near the vents		Paralvinella worms

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•MIDDLE VALLEY region just off the Juan de Fuca Ridge; 2.4 km deep

White smoker chimneys			Sulfide SEEP with unnamed species of Vesicomyid clams (see close-up of clam in ANIMALS section below)		Unidentified octopod near Middle Valley site		Unidentified sea cucumber near Middle Valley site

•ANIMALS brought back to the ship from the Juan de Fuca ridge, on ALVIN:

Paralvinella worms (in a vent chimney, left)		Ridgeia tubeworms (lying on Paralvinellid worms, left)			Scale worms (covered with bacterial filaments, right)
Maldonid worm	Galatheid crab from Middle Valley seep	Pycnogonid	Limpet Lepidodrilus	Limpet	Unnamed species of Vesicomyid clam from Middle Valley seeps		Anemone near Middle Valley seeps

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B. Mediterranean Sea; Mid-Atlantic Ridge; East Pacific Rise

A shallow hydrothermal vent off Vulcano, an Italian island in the Mediterranean. Note the sulfur deposits. For the deeper vents on the mid-ocean ridges, see: ONR site for animations, pictures, detailed information.	Bathymodiolus mussel from the Mid-Atlantic Ridge (provided by Cindy Van Dover). These have bacterial symbionts in their gills.	Rimicaris shrimp from the Mid-Atlantic Ridge (provided by Cindy Van Dover). These unique animals swim in and out of hot vents, have no eyestalks, but have unique eyepatches on their backs. Dr. Van Dover hypothesizes that these sense faint light (either infrared or from chemiluminescent reactions) from the vents.	The most "famous" animals of the hydrothermal vents are the giant Riftia tubeworms (vestimentiferans; Siboginid family of polychaetes). They are up to 2 m (6 feet) long! They have no guts, and live off their symbionts (see SEEP TUBEWORM for more on this process). For better pictures and a video, see U. Delaware Tubeworm site and Peter Batson's photos below.

C. PETER BATSON'S PHOTOS

BELOW are copyrighted photos courtesy of PETER BATSON, author of Deep New Zealand - Blue Water, Black Abyss. Please contact him for permission at his website, ExploreTheAbyss. See MIDWATER page for more of his photos.
Alvinella, a polychaete tubeworm that may be able to live in water of 50C or higher.	Tevnia, a small vestimentiferan tubeworm often found with Riftia.	A plume of Riftia (see description of these tubeworms under my photo, above right)	A Riftia body out of its tube	Brittle stars, limpets at a vent	Thermarces fish at a vent	Munidopsis galatheid crab	Bythograea crab at a vent

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HOME PAGE: CONTENTS, ZONES

1. Bacteria, UNKNOWNS, WORMS

2. BATHYAL and ABYSSAL FISHES

3. ECHINODERMS

4. CNIDARIA, Porifera

5. MOLLUSCS, CRUSTACEA, PYCNOGONIDA

6. MIDWATER (MESOPELAGIC)

7. SURFACE (EPIPELAGIC)