- Title Information
- Title
- Reconstructing natural modes of Pacific climate variability by geochemical
analysis of ocean sediment off Baja California, Mexico
- Name:
Personal
- Name Part
- O'Mara, Nicholas
- Role
- Role Term:
Text
- creator
- Name:
Personal
- Name Part
- Herbert, Timothy
- Role
- Role Term:
Text
- advisor
- affiliation
- Brown University. Department of Earth, Environmental and Planetary
Sciences
- Type of Resource
- still image
- Genre (aat)
(usage="primary")
- posters
- Origin Information
- Place
- Place Term:
Text
- Providence
- Publisher
- Brown University
- Date Created
(keyDate="yes", encoding="w3cdtf")
- 2015-08-07
- Physical Description
- Extent
(supplied="yes")
- 1 poster
- digitalOrigin
- reformatted digital
- Language
(usage="primary")
- Language Term
- eng
- Abstract
- The Pacific Ocean plays a key role in controlling natural periodic changes in
regional and global climate. Physical couplings between the oceanic and the atmospheric
systems result in variations in local sea surface temperature (SST), coastal marine
productivity, and global heat distribution. The El Niño Southern Oscillation (ENSO) and the
Pacific Decadal Oscillation (PDO) are two of these forms of physical coupling variability, or
modes, that have significant climatic effects on interannual and decadal timescales,
respectively. In order to understand how these phenomena have changed over Earth's history, we
must supplement and extend the modern record of SST back in time using paleotemperature
proxies. In this study, we analyzed organic compounds called alkenones produced by Emiliania
huxleyi, a type of marine algae. The ratio of alkenones produced that contain two double bonds
to those that contain three double bonds has been shown to correlate linearly with the algal
growth temperature. When these algae die, they sink to the bottom and the alkenones are
preserved in in the sediment. Using sediment cored off the coast of Baja California, Mexico,
an area that has been shown to be strongly influenced by both ENSO and PDO, and we performed
chemical analysis by gas chromatography in order to quantify the alkenone ratio and establish
an SST record for this region. Additionally, we used the total amount of alkenones as a proxy
for regional productivity. Our inferred record is consistent with the historical record for
the region and demonstrates the influence ENSO and PDO have on the coastal SST and
productivity. These results give us confidence in the use of this method to sample deeper,
pushing further back in time beyond the limits of historical data to establish a long-term
paleoclimate record for the region, which could elucidate how ENSO and PDO have varied in the
past under various global climatic conditions, century to century.
- Subject (LCSH)
- Topic
- Paleoclimatology
- Subject (LCSH)
- Topic
- Pacific Ocean
- Subject (LCSH)
- Topic
- Phytoplankton
- Identifier:
DOI
- 10.26300/t47v-gn19