AMPHIPODS (AMPHIPODA, GAMMARIDEA) AT THE GOREVOY UTES OIL AND METHANE SEEP, LAKE BAIKAL

摘要

We examined amphipods collected from aboard the deepwater manned submersibles "Mir-1" and "Mir-2" at oil and methane seeps near Cape Gorevoy Utes (Central Baikal). Most of the 23 taxa registered inhabit the entire Lake Baikal within a wide depth range. Two species of the genus Echiuropus are probably new. Leptostenus leptocerus (Dybowsky, 1874), that, until now, was regarded as a rare species, is likely to be an indicator for methane and oil discharge areas. Additional data on the morphology of this species were obtained; cuticular sensory (lateral line organs) and nonsensory microstructures were examined by scanning electron microscopy. The density of nectobenthic amphipods was 5-6 times higher on bitumen mounds than that at neighbouring sites with flat bottom. Maximum density of benthic amphipods was recorded on bacterial mats. No amphipods were observed at the bottom with large oil patches. High density of amphipods at the oil-methane seep is attributed to highly structured habitats and food abundance.