Changes in Southern Ocean bottom water environments associated with the Middle Eocene Climatic Optimum (MECO)

Episodes of intensified biological productivity in the subtropical Atlantic Ocean during the termination of the Middle Eocene Climatic Optimum (MECO)

“…Crucially, the relatively muted benthic foraminiferal assemblage response and cooccurrence of both oligotrophic and eutrophic species (Table ) imply that, taxonomically at least, benthic foraminifera were relatively insensitive to the environmental changes during the early stages of the MECO at ODP Site 1051. This is in stark contrast to the pronounced benthic foraminiferal response associated with the rapid onset of the PETM [e.g., Thomas , ; Thomas and Shackleton , ] and with a MECO section from the Southern Ocean [ Moebius et al ., ] and may imply that the rate of environmental change during the MECO was gradual enough in the subtropical Atlantic Ocean to enable benthic foraminifera to adapt.…”

“…Alternatively, the crossing of an ecological tolerance threshold may have precipitated the ecological changes associated with HPI‐1. In contrast, a site on the Kerguelen Plateau was subject to a significant faunal turnover during the more gradual warming phase of the MECO [ Moebius et al ., ], arguing against the possibility of gradual adaptation of taxa in the Southern Ocean.…”

X Conferencias y Seminarios del Doctorado en Geología

“…Records from a number of sites and sections, studied in different ocean basins and at different latitudes support this hypothesis (Boscolo-Galazzo et al 2013Moebius et al 2014Moebius et al , 2015Rivero-Cuesta et al 2018). Despite its comparable magnitude, the longer duration of MECO warming phase (ca.…”

“…These evidences have been interpreted as an increase in biological productivity during and after MECO peak, which led to eutrophic conditions and suggest correlation with the also two organic intervals (related with high productivity) at Alano. (Moebius et al, 2014) is located in the Indian sector of the Southern Ocean (Kerguelen Plateau) and was deposited at 1700 m below sea floor during the middle Eocene. A change in benthic foraminiferal dominance, from epifaunal to infaunal morphotypes, is recorded during warming and peak conditions.…”

Robustness of fossil fish teeth for seawater neodymium isotope reconstructions under variable redox conditions in an ancient shallow marine setting

“…Cerium oxidation takes place in shallow water through bacterial mediation [e.g., Moffett , ] and is typically followed by rapid scavenging/adsorption onto particles (e.g., by FeMn oxyhydroxides), resulting in pronounced negative Ce anomalies in seawater REE patterns (lower Ce concentrations in comparison to neighboring elements Pr and Nd) [e.g., Alibo and Nozaki , ; Bau , ; Tachikawa et al ., ]. Negative Ce anomalies have been reported for fish tooth REE patterns from pelagic sites [e.g., Elderfield and Pagett , ; Martin et al ., ; Moebius et al ., ; Scher et al ., ; Wright et al ., ]. Conversely, positive Ce anomalies in fish teeth have been linked to anoxic seawater conditions [e.g., Elderfield and Pagett , ; Wright et al ., ].…”