Biogeochemical Traits of a High Latitude South Pacific Ocean Calcareous Nannoplankton Community During the Oligocene.

Marine phytoplankton community composition influences the production and export of biomass and inorganic minerals (such as calcite), contributing to core marine ecosystem processes that drive biogeochemical cycles and support marine life. Here we use morphological and assemblage data sets within a size-trait model to investigate the mix of cellular biogeochemical traits (size, biomass, calcite) present in high latitude calcareous nannoplankton communities through the Oligocene (ca. 34-26 Ma) to better understand the biogeochemical consequences of past climate variability on this major calcifying phytoplankton group.

Algal plankton turn to hunting to survive and recover from end-Cretaceous impact darkness.

The end-Cretaceous bolide impact triggered the devastation of marine ecosystems. However, the specific kill mechanism(s) are still debated, and how primary production subsequently recovered remains elusive. We used marine plankton microfossils and eco-evolutionary modeling to determine strategies for survival and recovery, finding that widespread phagotrophy (prey ingestion) was fundamental to plankton surviving the impact and also for the subsequent reestablishment of primary production.

On impact and volcanism across the Cretaceous-Paleogene boundary.

The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction. We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic outgassing.

Diversity decoupled from ecosystem function and resilience during mass extinction recovery.

The Chicxulub bolide impact 66 million years ago drove the near-instantaneous collapse of ocean ecosystems. The devastating loss of diversity at the base of ocean food webs probably triggered cascading extinctions across all trophic levels and caused severe disruption of the biogeochemical functions of the ocean, and especially disrupted the cycling of carbon between the surface and deep sea. The absence of sufficiently detailed biotic data that span the post-extinction interval has limited our understanding of how ecosystem resilience and biochemical function was restored; estimates of ecosystem 'recovery' vary from less than 100 years to 10 million years.

Orbitally Forced Hyperstratification of the Oligocene South Atlantic Ocean.

Pelagic sediments from the subtropical South Atlantic Ocean contain geographically extensive Oligocene ooze and chalk layers that consist almost entirely of the calcareous nannofossil Braarudosphaera. Poor recovery and the lack of precise dating of these horizons in previous studies has limited the understanding of the number of acmes, their timing and durations, and therefore their likely cause. Here we present a high-resolution, astronomically tuned stratigraphy of Braarudosphaera oozes (29.

Warm plankton soup and red herrings: calcareous nannoplankton cellular communities and the Palaeocene-Eocene Thermal Maximum.

Past global warming events such as the Palaeocene-Eocene Thermal Maximum (PETM-56 Ma) are attributed to the release of vast amounts of carbon into the ocean, atmosphere and biosphere with recovery ascribed to a combination of silicate weathering and organic carbon burial. The phytoplanktonic nannoplankton are major contributors of organic and inorganic carbon but their role in this recovery process remains poorly understood and complicated by their contribution to marine calcification. Biocalcification is implicated not only in long-term carbon burial but also both short-term positive and negative climatic feedbacks associated with seawater buffering and responses to ocean acidification.

Coccolithophore calcification response to past ocean acidification and climate change.

Anthropogenic carbon dioxide emissions are forcing rapid ocean chemistry changes and causing ocean acidification (OA), which is of particular significance for calcifying organisms, including planktonic coccolithophores. Detailed analysis of coccolithophore skeletons enables comparison of calcite production in modern and fossil cells in order to investigate biomineralization response of ancient coccolithophores to climate change. Here we show that the two dominant coccolithophore taxa across the Paleocene-Eocene Thermal Maximum (PETM) OA global warming event (~56 million years ago) exhibited morphological response to environmental change and both showed reduced calcification rates.

Comment on "Calcareous nannoplankton response to surface-water acidification around Oceanic Anoxic Event 1a".

Erba et al. (Reports, 23 July 2010, p. 428) attributed calcareous nannofossil morphology and assemblage changes across Cretaceous Oceanic Anoxic Event 1a to the effects of surface ocean acidification.

Stratigraphy of the Anthropocene.

The Anthropocene, an informal term used to signal the impact of collective human activity on biological, physical and chemical processes on the Earth system, is assessed using stratigraphic criteria. It is complex in time, space and process, and may be considered in terms of the scale, relative timing, duration and novelty of its various phenomena. The lithostratigraphic signal includes both direct components, such as urban constructions and man-made deposits, and indirect ones, such as sediment flux changes.

The Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary.

The Cretaceous-Paleogene boundary approximately 65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India.

Nannoplankton extinction and origination across the Paleocene-Eocene Thermal Maximum.

The Paleocene-Eocene Thermal Maximum (PETM, approximately 55 million years ago) was an interval of global warming and ocean acidification attributed to rapid release and oxidation of buried carbon. We show that the onset of the PETM coincided with a prominent increase in the origination and extinction of calcareous phytoplankton. Yet major perturbation of the surface-water saturation state across the PETM was not detrimental to the survival of most calcareous nannoplankton taxa and did not impart a calcification or ecological bias to the pattern of evolutionary turnover.