Benthic foraminifera and phytodetritus species in sediments from DSDP Leg 85, and ODP Legs 113 and 143

• Main Authors: Thomas, Ellen, Gooday, Andrew J
• Format: Dataset
• Language: English
• Published: PANGAEA 1996
• Subjects: 113-689; 113-690; 143-865; 85-573; 85-574; 85-575; COMPCORE; Composite Core; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Joides Resolution; Leg113; Leg143; Leg85; North Pacific/FLANK; North Pacific/TROUGH; North Pacific Ocean; Ocean Drilling Program; ODP; South Atlantic Ocean; Pacific; Antarc*; Antarctica
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.712704; https://doi.org/10.1594/PANGAEA.712704

From late middle Eocene through earliest Oligocene, high-latitude regions cooled, and by the end of the period, continental ice sheets existed in Antarctica. Diversity of planktonic microorganisms declined, and modern groups of terrestrial vertebrates originated. Coeval faunal changes in deep-sea benthic foraminifers have been related to cooling of deep waters and increased oxygenation. Cooling, however, occurred globally, whereas species richness declined at high latitudes and not in the tropics. The late Eocene and younger lower-diversity, high-latitude faunas typically contain common Epistominella exigua and Alabaminella weddellensis, opportunistic phytodetritus-exploiting species that indicate a seasonally fluctuating input of organic matter to the sea floor. We speculate that the species-richness gradient and increase in abundance of phytodetritus-exploiting species resulted largely from the onset of a more unpredictable and seasonally fluctuating food supply, especially at high latitudes.