Biogeochemical significance of pelagic ecosystem function: an end-Cretaceous case study

Abstract

One contribution of 17 to a theme issue 'Biodiversity and ecosystem functioning in dynamic landscapes'. Pelagic ecosystem function is integral to global biogeochemical cycling, and plays a major role in modulating atmospheric CO 2 concentrations ( pCO 2 ). Uncertainty as to the effects of human activities on marine ecosystem function hinders projection of future atmospheric pCO 2 . To this end, events in the geological past can provide informative case studies in the response of ecosystem function to environmental and ecological changes. Around the Cretaceous-Palaeogene (K-Pg) boundary, two such events occurred: Deccan large igneous province (LIP) eruptions and massive bolide impact at the Yucatan Peninsula. Both perturbed the environment, but only the impact coincided with marine mass extinction. As such, we use these events to directly contrast the response of marine biogeochemical cycling to environmental perturbation with and without changes in global species richness. We measure this biogeochemical response using records of deep-sea carbonate preservation. We find that Late Cretaceous Deccan volcanism prompted transient deep-sea carbonate dissolution of a larger magnitude and timescale than predicted by geochemical models. Even so, the effect of volcanism on carbonate preservation was slight compared with bolide impact. Empirical records and geochemical models support a pronounced increase in carbonate saturation state for more than 500 000 years following the mass extinction of pelagic carbonate producers at the K-Pg boundary. These examples highlight the importance of pelagic ecosystems in moderating climate and ocean chemistry.

Biodiversity and ecosystem functioning in dynamic landscapes

“…In another case study, two carbon cycle perturbations during the Cretaceous are investigated [70]. Interestingly, the results suggest that the oceanic carbon cycle may be remarkably resilient to variation in abiotic conditions, whereas the effects of mass mortality of marine calcifiers on the oceanic carbon cycle persisted for millions of years [70]. Overall, these studies document the difference between models and empirical data from the fossil record, suggesting biodiversity effects on ecosystem functioning that are minor or major, respectively.…”

“…In a case study using the long-term biological monitoring and paleoecological records in a deep-sea soft-sediment environment, ecosystem functions increase with the number of species across decadal to millennial times scales, whereas ecosystem stability does not vary [69]. In another case study, two carbon cycle perturbations during the Cretaceous are investigated [70]. Interestingly, the results suggest that the oceanic carbon cycle may be remarkably resilient to variation in abiotic conditions, whereas the effects of mass mortality of marine calcifiers on the oceanic carbon cycle persisted for millions of years [70].…”

Latest Cretaceous climatic and environmental change in the South Atlantic region

“…Regarding open ocean plankton, little evidence exists for loss of species or population abundance during Late Cretaceous Deccan volcanism [ Henehan et al , ]. Nevertheless, several late Maastrichtian ecological signals, such as anomalous abundances, migrations and dwarfism amongst planktic foraminifera [ Olsson et al , ; Abramovich et al , ; Keller et al , ] and calcareous nannoplankton species [ Thibault and Gardin , ; Thibault and Husson , , and references therein] and the global bloom of the dinoflagellate Manumiella seelandica [ Habib and Saeedi , ] hint toward biotic response to late Maastrichtian climate changes.…”

X Conferencias y Seminarios del Doctorado en Geología

“…Los dos intervalos con valores de fragmentación elevados tienen equivalencia temporal de entre 66,36 y 66,28 Ma para el primer intervalo y de entre 66,21 y 66,18 Ma para el segundo, usando para ello el valor de tasa de sedimentación constante de 4,5cm/ka y una edad para el límite K/Pg de 66,04 Ma (Renne et al, 2013). Dichos intervalos se han podido correlacionar intervalos equivalentes del Site 525, y ODP 1267 del Atlántico Sur (Kucera et al, 1997;Henehan et al, 2016) y del Pacífico como el ODP site 1209, (Dameron et al, 2017;Henehan et al, 2016) lo que sugiere que es un fenómeno global.…”