Showing papers by "Andrew J. Gooday published in 1995"

Micro‐ and Nanoforaminifera from Abyssal Northeast Atlantic Sediments: A Preliminary Report

Abstract: Rose Bengal stained benthic foraminifera which pass through a 63 μm mesh (microforaminifera and nanoforaminifera) have been extracted by handsorting the fine sieve residues (> 45 μm, 31 μm, 28 μm, 20 μm, 15 μm) of abyssal sediment samples. The samples were collected using a multiple corer in four areas of the northeast Atlantic between 31° N and 59° N. The abundance of these minute foraminifera varied from 2 specimens per 1 cm2 (Madeira Abyssal Plain) to > 110 per 1 cm2 (BIOTRANS area). They include a variety of taxa, the most common being certain rotaliid species, hormosinaceans and other multilocular agglutinated forms, the unilocular agglutinated genus Lagenammina, soft-bodied agglutinated sphaeres and flasks (saccamminids and psammosphaerids) and allogromiids. Some specimens are < 63 μm in maximum dimension but others belonging to elongate taxa are longer. Two samples taken 10 cm apart on the Porcupine Abyssal Plain suggest that minute foraminifera may be patchily distributed on a small scale. One sample, which was overlain by substantial amounts of phytodetritus, contained > 100 stained specimens (> 30 per 1 cm2) while the other, in which much less phytodetritus was present, yielded only 10 specimens (2.9 per 1 cm2). This observation suggests that some micro- and nanoforaminifera may flourish in the presence of decaying organic matter, perhaps consuming the associated bacteria. The presence of phytodetritus may also explain why two of our samples from the Madeira Abyssal Plain (MAP) contained an order of magnitude more stained tiny foraminifera than two other MAP samples in which phytodetritus was absent.

The taxonomy and ecology of Crithionina delacai sp. nov., and abundant large agglutinated foraminifer from Explorers Cove, Antarctica

Abstract: We describe Crithionina delacai, a new large (up to 6.5 mm) agglutinated foraminifer that differs from related species (notably C. granum) in the composition and arrangement of particles within the test. The new species is abundant at a 28-m-deep site in Explorers Cove, McMurdo Sound, Antarctica. This unusually shallow-water occurrence for a species of Crithionina probably reflects the tranquil, cold (-1.8 degrees C), thermally stable, and relatively oligotrophic conditions that prevail at our study site. Crithionina delacai lives infaunally in the top 1 cm of sediment and apparently feeds on diatoms. Its abundance at depths accessible to SCUBA divers provides a unique opportunity to conduct detailed biological studies of this predominantly deep-sea genus.