Two purple Beroe ctenophores (or comb jellies) swimming around each other at Southern Hydrate Ridge. One has its mouth open, showing how they can engulf other ctenophores to feed. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

The feeding tentacles of a reddish siphonophore seen at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A purple Beroe ctenophore (or comb jelly) facing downwards at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A red Beroe ctenophore (or comb jelly) facing the camera with its mouth open at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A Voragonema pedunculata jellyfish at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

Approaching a Voragonema pedunculata jellyfish at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A red Poralia rufescens jellyfish getting swept around by the currents at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A purple Beroe ctenophore (or comb jelly) near the seafloor at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A purple sea anemone next to some carbonate rocks at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A Tanner crab crawling on the seafloor at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A white Pedicellasterid sea star on the seafloor at Southern Hydrate Ridge, next to a number of ophiuroids (brittle stars). Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A purple Beroe ctenophore (or comb jelly) at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A translucent Bolinopsis ctenophore (or comb jelly) at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A purple Beroe ctenophore (or comb jelly) at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A red Beroe ctenophore (or comb jelly) at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

Octopus squid (Octopoteuthis deletron) seen in the midwater during ascent at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

A close-up shot of a Voragonema pedunculata jelly at Southern Hydrate Ridge. Credit: UW/NSF-OOI/WHOI; J2-1744, V25.

Close-up shot of an opalescent nudibranch (Hermissenda crassicornis) on the Slope Base Shallow Profiler platform. Credit: UW/NSF-OOI/WHOI; J2-1699, V25.

School of yellowfin tuna seen during descent at OR Offshore site. Credit: UW/NSF-OOI/WHOI; J2-1698, V25.

A pink squat lobster peeks at the ROV from the shelter of large feather stars (unstalked crinoids) and other organisms growing on the Axial Base profiler platform. Credit: UW/NSF-OOI/WHOI; J2-1791, V26.

Feathery bryozoans, crinoids, nudibranchs, and other organisms encrusting the Axial Base profiler platform and camera. Credit: UW/NSF-OOI/WHOI; J2-1791, V26.

White clusters of nudibranch eggs hidden among bryozoans encrusting the Axial Base profiler platform. Credit: UW/NSF-OOI/WHOI; J2-1791, V26.

A cluster of flower-like benthic ctenophores (likely Tjalfiella species) growing on the loop of polypropylene line on top of the HPIES instrument at Axial Base (2700 m). Credit: UW/NSF-OOI/WHOI; J2-1790, V26.

A small purple anemone sits in the sediment at the Axial Base site. Credit: UW/NSF-OOI/WHOI; J2-1790; V26.

A basalt hill covered in skinny chemosynthetic tube worms and white bacterial mats at Axial Caldera International District Vent Field. Credit: UW/NSF-OOI/WHOI; J2-1788; V26.

The top of a bush of skinny chemosynthetic tube worms, filamentous bacteria, and encrusting limpets at Axial Caldera International District Vent Field. Credit: UW/NSF-OOI/WHOI; J2-1788; V26.

Bushes of skinny chemosynthetic tube worms at Axial Caldera International District Vent Field. Credit: UW/NSF-OOI/WHOI; J2-1788; V26.