Foraminiferal associations in Port Pegasus.Stewart Island, New Zealand

Abstract

Census data on benthic foraminiferal tests in 56 seafloor sediment samples (high tide to 45 m depth; slightly brackish to normal marine) in Port Pegasus, south‐east Stewart Island, are analysed by cluster analysis. The faunal samples are grouped into six associations: A. Trifarina angulosa/Textularia proxispira/Miliolinella subrotundata—current‐swept passages and adjacent port; B. Notorotalia finlayi/Quinqueloculina delicatula/Nonionella flemingi—muddy fine sand at 22–30 m; C. Notorotalia zelandica/Elphidium novozealandicum—sheltered bays at 2.5–26 m; D. Rosalina bradyi—shallow subtidal amongst rocky reefs; E. Ammonia beccarii/Elphidium advenum depressulum/Haynesina depressula—0.5–6 m, sheltered bays and channels of Cooks Arm; F. Miliammina fusca—brackish, intertidal. In the entrance passages and exposed shelf (5–45 m depth) planktics comprise 15–30% of the total foraminiferal tests. Directly inside the passages in Port Pegasus, planktics comprise 30–65% of the fauna. These are dominated by small species that have been swept inshore by the predominant onshore swells and winds and carried into the port by strong tidal currents before settling out of suspension. The small, calcareous tests of benthic Cassidulina carinata and Trifarina angulosa also have distribution patterns consistent with some current transport into Port Pegasus.

Keywords:

• Foraminifera
• benthic foraminiferal associations
• planktic foraminiferal abundances
• ecological distribution
• post‐mortem transport of tests
• Port Pegasus
• Stewart Island
• New Zealand
• cluster analysis
• association acores