A research ship off South America has reported the discovery of new hot water geysers on the bottom of the Pacific Ocean and new "unidentified, fascinating" sea creatures, apparently never seen before.

The fields of geysers and array of sea creatures found by the research ship Melville are apparently the largest of the "ocean vent communities" yet discovered. The first was found in 1977, off the Galapogos Islands, and the second some time later off Mexico. Last week's radio message from the Melville told of the third and fourth sightings.

Together the finds are probably the greatest discovery of new animal communities in the history of biology, according to Frederick Grassle, a marine biologist at the Woods Hole Oceanographic Institution in Massachusetts. Grassle was on the Galapogos expedition.

Until the discoveries in 1977, the sea floor was known only as a near-freezing, pitch-black terrain, nearly barren of life. Animals there must live without light and endure pressure 250 to 300 times that on land.

But hot water gushing up through small "smokestacks" in the sea floor has been found to produce conditions under which small communities of creatures can live.

These communities range from 30 to 500 feet in diameter and center on the hot geysers, their source of life.

The Melville's radio reports to the National Science Foundation, which is sponsoring the research, began Thursday night and continues through the weekend.

Dr. Neil Anderson, director of the program for NSF, said the researchers found -- at a depth of 9,000 feet in an area parallel to Peru and due south of the Galapogos Islands -- the same kinds of creatures first discovered at other vents -- including sixfoot, blood-red "tube worms," footwide red clams with white shells, and new varieties of crabs, limpets and jellyfish-like plants called dandelions.

According to the radio messages, other creatures were found -- including a type of starfish -- that had not been seen at the other vent sites.

The messages also referred to "unidentified fascinating objects for the biologists to pursue," Andersen said.

The Melville also took the first samples of rock from the vents, and samples of the geyser water, which ranges from about 75 to 750 degrees Fahrenheit. The surrounding water is about 35 degrees.

The patches of life found by the Melville in one area, around a very hot geyser, extended to an area of 250 feet by 500 feet.

To see the vent areas, the researchers used three video color cameras mounted on a sled, which was dropped to the ocean bottom and towed around the site. Samples were gathered by dredging, drawing cores and using electrically opened bottles to draw geyser water.

The unusual biology of the creatures at the vent sites apparently allows them to use the chemicals in the geyser as energy sources, instead of using light and photosynthesis, as life forms on the earth's surface do.

The geyser water in minerals and contains large amounts of hydrogen sulfide and carbon dioxide. A type of bacteria, which breaks down the hydrogen sulfide to gain energy, is apparently the key to the vent communities' life cycle.

All the vent sites discovered so far are in the crest of the East Pacific Ridge, an underwater mountain range. It is at a point where two great plates of the earth's crust are joined, but are slowly pulling apart, allowing the venting of hot water and sometimes molten rock.