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| Kender, Sev; Mcclymont, Erin L.; Elmore, Aurora C.; Emanuele, Dario; Leng, Melanie J.; Elderfield, Henry. |
| Understanding the interaction between climate and biotic evolution is crucial for deciphering the sensitivity of life. An enigmatic mass extinction occurred in the deep oceans during the Mid Pleistocene, with a loss of over 100 species (20%) of sea floor calcareous foraminifera. An evolutionarily conservative group, benthic foraminifera often comprise 450% of eukaryote biomass on the deep-ocean floor. Here we test extinction hypotheses (temperature, corrosiveness and productivity) in the Tasman Sea, using geochemistry and micropalaeontology, and find evidence from several globally distributed sites that the extinction was caused by a change in phytoplankton food source. Coccolithophore evolution may have enhanced the seasonal 'bloom' nature of primary... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00496/60723/65259.pdf |
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| Nilsson-kerr, Katrina; Anand, Pallavi; Holden, Philip B.; Clemens, Steven C.; Leng, Melanie J.. |
| Most of Earth’s rain falls in the tropics, often in highly seasonal monsoon rains, which are thought to be coupled to the inter-hemispheric migrations of the Inter-Tropical Convergence Zone in response to the seasonal cycle of insolation. Yet characterization of tropical rainfall behaviour in the geologic past is poor. Here we combine new and existing hydroclimate records from six large-scale tropical regions with fully independent model-based rainfall reconstructions across the last interval of sustained warmth and ensuing climate cooling between 130 to 70 thousand years ago (Marine Isotope Stage 5). Our data-model approach reveals large-scale heterogeneous rainfall patterns in response to changes in climate. We note pervasive dipole-like tropical... |
| Tipo: Text |
Palavras-chave: Palaeoceanography; Palaeoclimate. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00685/79705/82497.pdf |
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| Sutton, Jill N.; Andre, Luc; Cardinal, Damien; Conley, Daniel J.; De Souza, Gregory F.; Dean, Jonathan; Dodd, Justin; Ehlert, Claudia; Ellwood, Michael J.; Frings, Patrick J.; Grasse, Patricia; Hendry, Katharine; Leng, Melanie J.; Michalopoulos, Panagiotis; Panizzo, Virginia N.; Swann, George E. A.. |
| Silicon (Si) is the second most abundant element in the Earth's crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial... |
| Tipo: Text |
Palavras-chave: C - N - O - Si isotopes; Biogenic silica; Element/Si ratios; Biogeochemical cycles; Silicon. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00431/54217/55547.pdf |
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