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The Miocene is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words μείων and καινός and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene.
El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. The Southern Oscillation is the accompanying atmospheric component, coupled with the sea temperature change: El Niño is accompanied by high air surface pressure in the tropical western Pacific and La Niña with low air surface pressure there. The two periods last several months each and typically occur every few years with varying intensity per period.
The Paleocene–Eocene thermal maximum (PETM), alternatively "Eocene thermal maximum 1" (ETM1), and formerly known as the "Initial Eocene" or "Late Paleocene thermal maximum", was a time period with a more than 5–8 °C global average temperature rise across the event. This climate event occurred at the time boundary of the Paleocene and Eocene geological epochs. The exact age and duration of the event is uncertain but it is estimated to have occurred around 55.5 million years ago (Ma).
Foraminifera are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell of diverse forms and materials. Tests of chitin are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment, while a smaller number float in the water column at various depths, which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA.
Paleoceanography is the study of the history of the oceans in the geologic past with regard to circulation, chemistry, biology, geology and patterns of sedimentation and biological productivity. Paleoceanographic studies using environment models and different proxies enable the scientific community to assess the role of the oceanic processes in the global climate by the re-construction of past climate at various intervals. Paleoceanographic research is also intimately tied to paleoclimatology.
The term Middle Miocene disruption, alternatively the Middle Miocene extinction or Middle Miocene extinction peak, refers to a wave of extinctions of terrestrial and aquatic life forms that occurred around the middle of the Miocene, roughly 14 million years ago, during the Langhian stage of the Miocene. This era of extinction is believed to have been caused by a relatively steady period of cooling that resulted in the growth of ice sheet volumes globally, and the reestablishment of the ice of the East Antarctic Ice Sheet (EAIS). Cooling that led to the Middle Miocene disruption is primarily attributed to orbitally paced changes in oceanic and atmospheric circulation due to continental drift. These may have been amplified by CO2 being pulled out of the Earth's atmosphere by organic material before becoming caught in different locations like the Monterey Formation. This period was preceded by the Miocene Climatic Optimum, a period of relative warmth from 18 to 14 Ma.
Ocean deoxygenation is the reduction of the oxygen content in different parts of the ocean due to human activities. It occurs firstly in coastal zones where eutrophication has driven some quite rapid declines in oxygen to very low levels. This type of ocean deoxygenation is also called "dead zones". Secondly, there is now an ongoing reduction in oxygen levels in the open ocean: naturally occurring low oxygen areas are now expanding slowly. This expansion is happening as a consequence of human caused climate change. The resulting decrease in oxygen content of the oceans poses a threat to marine life, as well as to people who depend on marine life for nutrition or livelihood. Ocean deoxygenation poses implications for ocean productivity, nutrient cycling, carbon cycling, and marine habitats.
During the Pliocene epoch, the Earth's climate became cooler and drier, as well as more seasonal, marking a transition between the relatively warm Miocene to the cooler Pleistocene.
Maureen E. "Mo" Raymo is an American paleoclimatologist and marine geologist. She is the Co-Founding Dean of the Columbia Climate School, Director of the Lamont–Doherty Earth Observatory of Columbia University, the G. Unger Vetlesen Professor of Earth & Environmental Sciences, and Director of the Lamont–Doherty Core Repository at the Lamont–Doherty Earth Observatory of Columbia University. She is the first female climate scientist and first female scientist to head the institution.
Tessa Michelle Hill is an American marine geochemist and oceanographer. She is a professor at the University of California, Davis, and a resident professor at its Bodega Marine Laboratory. She is a Fellow of the California Academy of Sciences, and in 2016 was named a Leshner Public Engagement Fellow of the American Association for the Advancement of Science. In that year she also received the US Presidential Early Career Award for Scientists and Engineers (PECASE).
Amy C. Clement is an atmospheric and marine scientist studying and modeling global climate change at the University of Miami's Rosenstiel School of Marine and Atmospheric Science.
Cyclonic Niño is a climatological phenomenon that has been observed in climate models where tropical cyclone activity is increased. Increased tropical cyclone activity mixes ocean waters, introducing cooling in the upper layer of the ocean that quickly dissipates and warming in deeper layers that lasts considerably more, resulting in a net warming of the ocean.
Amelia E. Shevenell is an American marine geologist who specializes in high-latitude paleoclimatology and paleoceanography. She is currently a Professor in the College of Marine Science at the University of South Florida. She has made notable contributions to understanding the history of the Antarctic ice sheets and published in high-impact journals and, as a result, was awarded full membership of Sigma Xi. She has a long record of participation in international ocean drilling programs and has served in leadership positions of these organizations. Shevenell served as the elected Geological Oceanography Council Member for The Oceanography Society (2019-2021).
Ocean dynamical thermostat is a physical mechanism through which changes in the mean radiative forcing influence the gradients of sea surface temperatures in the Pacific Ocean and the strength of the Walker circulation. Increased radiative forcing (warming) is more effective in the western Pacific than in the eastern where the upwelling of cold water masses damps the temperature change. This increases the east-west temperature gradient and strengthens the Walker circulation. Decreased radiative forcing (cooling) has the opposite effect.
Margaret (Peggy) Delaney is marine geochemist known for her research on trace elements to examine changes in ocean chemistry over time.
Jean Lynch-Stieglitz is a paleoceanographer known for her research on reconstructing changes in ocean circulation over the last 100,000 years.
Sidney Hemming is an analytical geochemist known for her work documenting Earth's history through analysis of sediments and sedimentary rocks. She is a professor of earth and environmental sciences at Columbia University.
Delia Wanda Oppo is an American scientist who works on paleoceanography where she focuses on past variations in water circulation and the subsequent impact on Earth's climate system. She was elected a fellow of the American Geophysical Union in 2014.
Zanna Chase is an ocean-going professor of chemical oceanography and paleoceanography at the Institute of Marine and Antarctic Science, University of Tasmania, Australia. She has undertaken over 20 voyages on research vessels, and her areas of expertise are Antarctic paleoclimate, marine carbon cycle, radionuclides in the ocean, sediment geochemistry, paleoceanography, and marine biogeochemistry. In 2013 she was awarded an ARC Future Fellowship.
Global paleoclimate indicators are the proxies sensitive to global paleoclimatic environment changes. They are mostly derived from marine sediments. Paleoclimate indicators derived from terrestrial sediments, on the other hand, are commonly influenced by local tectonic movements and paleogeographic variations. Factors governing the earth climate system include plate tectonics, which controls the configuration of continents, the interplay between the atmosphere and the ocean, and the earth's orbital characteristics. Global paleoclimate indicators are established based on the information extracted from the analyses of geologic materials, including biological, geochemical and mineralogical data preserved in marine sediments. Indicators are generally grouped into three categories; paleontological, geochemical and lithological.
References
- 1 2 "Ravelo". Honors Program.
- 1 2 3 "How a daughter of immigrants became a leader in ocean and climate science – Sally Ride Science".
- 1 2 "Department Faculty". oceansci.ucsc.edu. Retrieved 2021-07-20.
- ↑ Ravelo, Ana Christina (1991). Reconstructing the tropical Atlantic seasonal thermocline using planktonic foraminifera (Thesis). OCLC 81392176.
- 1 2 "Q&A with Ana Christina Ravelo, PhD '91" (PDF). Columbia University. Archived (PDF) from the original on 2015-09-06. Retrieved July 20, 2021.
- ↑ Ravelo, A. C.; Fairbanks, R. G. (1992). "Oxygen Isotopic Composition of Multiple Species of Planktonic Foraminifera: Recorders of the Modern Photic Zone Temperature Gradient". Paleoceanography. 7 (6): 815–831. Bibcode:1992PalOc...7..815R. doi:10.1029/92PA02092. ISSN 1944-9186.
- ↑ Ravelo, A. C.; Fairbanks, R. G.; Philander, S. G. H. (1990). "Reconstructing tropical Atlantic hydrography using planktontic foraminifera and an ocean model". Paleoceanography. 5 (3): 409–431. Bibcode:1990PalOc...5..409R. doi:10.1029/PA005i003p00409. ISSN 1944-9186.
- ↑ Ren, Haojia; Sigman, Daniel M.; Martínez-García, Alfredo; Anderson, Robert F.; Chen, Min-Te; Ravelo, Ana Christina; Straub, Marietta; Wong, George T. F.; Haug, Gerald H. (2017). "Impact of glacial/interglacial sea level change on the ocean nitrogen cycle". Proceedings of the National Academy of Sciences of the United States of America. 114 (33): E6759–E6766. Bibcode:2017PNAS..114E6759R. doi: 10.1073/pnas.1701315114 . ISSN 0027-8424. JSTOR 26487067. PMC 5565415 . PMID 28760968.
- ↑ Pagani, Mark; Liu, Zhonghui; LaRiviere, Jonathan; Ravelo, Ana Christina (January 2010). "High Earth-system climate sensitivity determined from Pliocene carbon dioxide concentrations". Nature Geoscience. 3 (1): 27–30. Bibcode:2010NatGe...3...27P. doi:10.1038/ngeo724. ISSN 1752-0908.
- ↑ Wara, M. W.; Ravelo, Ana Christina; Delaney, Margaret L. (29 July 2005). "Permanent El Nino-Like Conditions During the Pliocene Warm Period". Science. 309 (5735): 758–761. doi: 10.1126/science.1112596 . JSTOR 3842403. PMID 15976271. S2CID 37042990.
- ↑ Marshall, Michael (May 25, 2011). "Pacific shouldn't amplify climate change". New Scientist. Retrieved July 20, 2021.
- ↑ Knudson, Karla P.; Ravelo, Ana Christina; Aiello, Ivano W.; Knudson, Christina P.; Drake, Michelle K.; Sakamoto, Tatsuhiko (2021). "Causes and timing of recurring subarctic Pacific hypoxia". Science Advances. 7 (23): eabg2906. doi: 10.1126/sciadv.abg2906 . ISSN 2375-2548. PMID 34078607.
- ↑ Rosane, Olivia (2021-06-03). "Dead Zones Have Recurred in the North Pacific for the Last 1.2 Million Years". EcoWatch. Archived from the original on 2021-06-03. Retrieved 2021-07-20.
- ↑ Dockrill, Peter. "'Dead Zones' Have Been Haunting The Ocean For Longer Than Anyone Ever Knew". ScienceAlert. Retrieved 2021-07-20.
- ↑ Stephens, Tim (October 12, 2020). "Ocean scientist Christina Ravelo honored as a Fellow of the California Academy of Sciences". UC Santa Cruz News. Archived from the original on 2020-10-13. Retrieved 2021-07-20.
- ↑ "California Academy of Sciences welcomes new Fellows, bestows annual awards". California Academy of Sciences. Retrieved 2021-07-20.
