Open AccessLinkages between rapid climate variability and deep‐sea benthic foraminifera in the deep Subantarctic South Atlantic during the last 95 kyr
Author(s) -
Diz Paula,
Barker Stephen
Publication year - 2015
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1002/2015pa002784
Subject(s) - phytodetritus , oceanography , stadial , geology , foraminifera , benthic zone , glacial period , younger dryas , paleoclimatology , climate change , abrupt climate change , north atlantic deep water , climatology , holocene , thermohaline circulation , paleontology , global warming , effects of global warming
We present a high‐resolution record of benthic foraminifera fauna from a sediment core retrieved from the South Cape Basin (Subantarctic South Atlantic) spanning the last glacial cycle (95 kyr). Information provided by benthic foraminiferal assemblages together with paleoclimate proxies from the same core allow us to interpret changes in the style of primary production (episodic versus sustained) in relation to abrupt climate oscillations. Our results indicate that fluctuations in the abundance of the phytodetritus‐related species, Epistominella exigua , are concomitant with millennial‐scale high‐latitude climate perturbations. Episodic phytoplankton blooms increased during a negative mode of the bipolar seesaw, irrespective of the magnitude of the perturbation (i.e., Heinrich stadial versus non‐Heinrich stadial events). We provide a hypothesis linking the frequency and intensity of these events to atmospheric perturbations, interhemispheric climate variability, and millennial‐scale changes in atmospheric CO 2 . A notable exception to the overall pattern is the generally high abundance of E. exigua across the globally synchronous onset of glacial marine oxygen isotope stage (MIS) 4, a period generally characterized by increased dustiness and low‐quality organic carbon as inferred by the percentage of the nonphytodetritus species. This highlights the special characteristics governing the onset of MIS 4 in the Subantarctic.