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Research on cold-seep sediments from Monterey Bay in the Pacific Ocean are presented, ranging in depths between 900 m to 1,000 m. Results indicate that bacteria and peroxisomes may assist foraminifera in inhabiting cold seep environments. Spiroplectammina biformis was the only species limited to the seep in these samples, but it has been observed in non-seep sites of other regions.

Author(s): Joan M. Bernhard (corresponding author) [1]; Kurt R. Buck [2]; Mark A. Farmer [3]; Samuel S. Bowser [4] It is generally agreed that the origin and initial diversification of [...]

The composition, biomass and spatial distribution of major plankton groups in the ice-edge zone of the Weddell and Scotia Seas were investigated. The purpose was to evaluate the effect of enhanced winter production in the ice-edge zone on nano- and microheterotrophs. To estimate the importance of nano- and microheterotrophs in the food web, their respiration requirements were estimated using allometric relationships. The role of advective processes and release of material from ice in structuring winter plankton assemblages wasalso evaluated by analysis of the distribution of selected species.

A hybrid population of mussels from the mid-Atlantic ridge (MAR) is exploited to test the strictly cytoplasmic maternal cotransmission (SCMC) hypothesis. The northern and southern mussel species differ diagnostically in their mitochondrial DNA sequences, and they integrate along an intermediate segment of the MAR axis.

Sulfide oxidizing bacterial mats are common in regions of the continental shelves characterized by high primary production and the resultant oxygen minimum zone. These mats are made up of several species of Beggiatoa and/or Thioploca, which oxidize sulfide that is generated in the sediment. Thioploca spp. inhabit a large polysaccharide sheath that encompasses bundles of 1-20 filaments (trichomes), each ranging from 3 to 60 μm in diameter. This sheath has been shown to be a critical component of the autecology of Thioploca. Analysis of Thioploca from cold seeps in Monterey Bay using light and transmission electron microscopy identified new and diverse microbial assemblages associated with interstitial spaces between trichomes, inside the sheath. Small diameter, non-vacuolate, filamentous prokaryotes were numerous. Amoebae, euglenozoa, ciliates and other protists of unknown affiliation were observed in sheaths. Most of the protists possessed food vacuoles and some protists showed ultrastructural evidence of endosymbionts. These observations suggest that Thioploca sheaths may serve as oases on the sea floor, providing nutritional and detoxification services to previously unrecognized microbial partners. [ABSTRACT FROM AUTHOR]

We report the finding of two species of Mantoniella from the Weddell Sea and Prydz Bay. Antarctica. As well as M. squamata, a cosmopolitan species, we describe M. Antarctica sp. Nov., the second species in this genus. M. Antarctica is covered with two distinctive types of discoid scales. The flagella bear only the smaller of the scale types whereas the cell body has both types, the larger overlying the smaller. [ABSTRACT FROM AUTHOR]

A significant amount of the primary production in the Southern Ocean and other ice-covered oceans takes place in localized ice edge plankton blooms. The dynamics of these blooms appear to be closely related to seasonal melting of sea ice. Algal cells released from the ice are a possible source of ice edge planktonic assemblages, but evidence for this "seeding" has been equivocal. We compared algal assemblages in ice and water in the Weddell Sea during the austral spring of 1983 at a receding ice edge with a well-developed ice edge bloom. The high degree of similarity between ice and water column assemblages, the spatial and temporal patterns in the distribution and abundances of species, and preliminary evidence for the viability and growth of ice-associated species provide evidence for seeding from sea ice of some species in Antarctica. [ABSTRACT FROM AUTHOR]