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Paleoclimate records of the El Niño Southern Oscillation
Different modes of ENSO-like events have been registered in paleoclimatic archives, showing different triggering methods, feedbacks and environmental responses to the geological, atmospheric and oceanographic characteristics of the time. These paleorecords can be used to qualitatively to provide a basis for preventive and conservation practices (Willis, et al., 2007).
| Series/ Epoch | Age Length of archive / Location / Type of archive or proxy | Description and References |
|---|---|---|
| Mid Holocene | 4150 ya
Vanuatu Coral Core |
Coral bleaching in Vanuatu coral records, indication of shoaling of thermocline, is analyzed for Sr/Ca and U/Ca content, from which Temperature is regressed. The Temperature variability shows that during the mid-Holocene, changes in the position of the anticyclonic gyre produced average to cold (La Nina) conditions, which were probably interrupted by strong warm events (El Niño), which might have produced the bleaching, associated to decadal variability. (Correge, 2000; Vara, 2013) |
| Holocene | 12000ya
Pallcacocha Lake, Ecuador Sediment core |
Core shows warm events with periodicities of 2–8 years, which become more frequent over the Holocene until about 1,200 years ago, and then decline, on top of which there are periods of low and high ENSO-related events, possibly due to changes in insolation. (Rodbell, 1999; Moy, 2002) |
| LGM | 45000ya
Australia Peat core |
Moisture variability in the Australian core shows dry periods related to frequent warm events (El Niño), correlated to DO events. Although no strong correlation was found with the Atlantic, it is suggested that the insolation influence probably affected both oceans, although the Pacific seems to have the most influence on teleconnection in annual, millennial and semi-precessional timescales. (Turney, 2004) |
| Pleistocene | 240 Kya
Indian and Pacific Coccolithophore in 9 deep sea cores |
9 deep cores in the equatorial Indian and Pacific show variations in primary productivity, related to glacial-interglacial variability and precessional periods (23 ky) related to changes in the thermocline. There is also indication that the equatorial areas can be early responders to insolation forcing. (Beaufort, 2001) |
| Pliocene | 2.8 Mya
Spain Lacustrine laminated sediments core |
The basin core shows light and dark layers, related to summer/autumn transition where more/less productivity is expected. The core shows thicker or thinner layers, with periodicities of 12, 6-7 and 2-3 years, related to ENSO, NAO and QBO, and possibly also insolation variability (sunspots). (Munoz, 2002) |
| Pliocene | 5.3 Mya
Equatorial Pacific Foraminifera in deep sea cores |
Deep sea cores at ODP site 847 and 806 show that the Pliocene warm period presented permanent El Niño-like conditions, possibly related to changes in the mean state of extratropical regions. (Wara, 2005) |
| Miocene | 5.92-5.32 Mya
Italy Evaporite varve thickness |
The varve close to the Mediterranean shows 2-7 year variability, closely related to ENSO periodicity. Model simulations show that there is more correlation with ENSO than NAO, and that there is a strong teleconnection with the Mediterranean due to lower gradients of temperature. (Galeotti, 2010) |
Improving an existing article
Identify what's missing from the current form of the article. Think back to the skills you learned while critiquing an article. Make notes for improvement in your sandbox. -- Add a paragraph on the ENSO variability in the paleorecords shows ... -- Add a section on this topic. Use a table to summarize several papers. Links to Pliocene Climate and others
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Dinoflagellates occur in most aquatic environments and during their life cycle, some species produce highly resistant organic-walled cysts for a dormancy period when environmental conditions are not appropriate for growth. Their living depth is relatively shallow (dependent upon light penetration), and closely coupled to diatoms on which they feed. Their distribution patterns in surface waters are closely related to physical characteristics of the water bodies, and nearshore assemblages can also be distinguished from oceanic assemblages. The distribution of dinocysts in sediments has been relatively well documented and has contributed to understanding the average sea-surface conditions that determine the distribution pattern and abundances of the taxa ([1]). Several studies, including [2] and [3] have compiled box and gravity cores in the North Pacific analyzing them for palynological content to determine the distribution of dinocysts and their relationships with sea surface temperature, salinity, productivity and upwelling. Similarly, [4] and [5] use a box core at 576.5 m of water depth from 1992 in the central Santa Barbara Basin to determine oceanographic and climatic changes during the past 40 kyr in the area.